Printer Friendly

Dietary composition of four stocks of pacific harbor seal (phoca vitulina richardii) in the northern california current large marine ecosystem as synthesized from historical data, 1931-2013.

Harbor Seals are generalist marine predators known to consume many species of commercial and conservation interest including salmonids, rockfish species, forage fish, crustaceans, and flatfish (TRC and COMES 2012). Examining ecological niche and dietary composition of marine predators is an essential component of ecosystem-based management of marine resources. Individual, localized studies assessing dietary composition of pinnipeds are one of the most often used methods to understand the ecological role of marine mammals. Such studies of Pacific Harbor Seal (Phoca vitulina richardii) foraging behaviors and dietary composition within the California Current Large Marine Ecosystem (CCLME) have been conducted for several decades. The CCLME extends from the northernmost boundary of the California Current System (CCS) at 50[degrees] N at the Salish Sea south to the Baja Peninsula (approximately 27[degrees] N). The CCLME is divided into 3 functional sections: (1) the northern region, from the Salish Sea to Cape Mendocino, California; (2) the central region, from Cape Mendocino South to Point Conception, California; and (3) the southern region, which extends south to Baja California (Checkley and Barth 2009).

The northern CCLME's coastal marine geography is defined by numerous bays and river inlets, as well as rocky volcanic reefs, rocky intertidal areas, and sandy shore-bottom zones. The northern CCLME is comprised of 4 genetically- and ecologically-distinct stocks of Pacific Harbor Seals: (1) the Oregon-Washington Coastal; (2) the Hood Canal; (3) the Southern Puget Sound; and (4) the Washington Northern Inland Waters stocks (Lamont and others 1996; Dishman 2011; Carretta and others 2015). The dividing northern extent of the Washington Inland Waters stock is the Salish Sea (Burg and others 1999). The Washington State region includes both estuarine and coastal habitat, as well as the 2642 [km.sup.2] Puget Sound. The Puget Sound, including the ecologically rich San Juan Islands, creates a unique inland marine ecosystem for Harbor Seals and their prey. It is home to 3 of the 4 genetically-distinct stocks Harbor Seal in the northern CCLME, including the Hood Canal stock, Southern Puget Sound stock, and Washington Northern Inland Waters (Puget Sound) stock (Carretta and others 2015). Harbor Seals are the most abundant species of pinniped in the Puget Sound with estimates of >15,000 individuals (Lance and Jeffries 2006, 2009a). Harbor Seals residing in the San Juan Islands number over 4000 and reside at more than 150 haul-out locations (Lance and Jeffries 2009a). The Oregon Coast region of the northern CCLME has more than 22 bays, many of which are locations of Harbor Seal haul-out and breeding sites (Brown and others 2005). The Columbia River, the largest river in the Pacific Northwest, hosts numerous Harbor Seal haul-out sites, including Desdemona Sands, Baker Bay, South Jetty, Grays Bay, Green Island, Miller Sands, Welch Island, and Wallace Island (Beach and others 1985).

Since 1931, a number of potentially comparative, quantitative frequency-of-occurrence (% FO) prey studies for Pacific Harbor Seals have been conducted for the northern CCLME. However, this information has not been compiled on a larger comparative scale to assess breadth of diet of the Harbor Seal populations in this overall region. The northern CCLME would particularly benefit from a synthesis of information, as marine mammal-fisheries interactions, development of marine reserves, and other management issues are becoming increasingly prevalent. For example, management of local salmon and other commercially-important fish, and sturgeon populations are of concern as they relate to local pinniped predation and management (Beach and others 1985).

Due to dietary generalism, the diets of the Harbor Seal populations in the northern CCLME are likely much more diverse and cross-regional than has been presented in individual papers that have focused on Harbor Seal diets in this region. To exam this hypothesis, I conducted a review of pertinent literature regarding Harbor Seal foraging ecology in the northern CCLME. My review reveals the broad variability of Pacific Harbor Seal diet composition within the northern CCLME, between regions, stocks and season.

METHODS

I conducted a literature review for all available sources published prior to and through May 2016 on a variety of academic search platforms, including Google Scholar ([C] Google, Inc.), Academic Search Premier ([C] Thomson Reuters), Google search engines, academic archives, and agency publications and reports. I utilized keywords relating to Harbor Seal diet in the Northern CCLME, including the terms 'Harbor Seal', 'Pacific Harbor Seal', 'Phoca vitulina richardii', 'foraging', 'fecal analysis', 'dietary', 'ecology', 'predation', 'diet', 'dive or diving', dietdietary composition', 'Washington', 'Oregon' 'Columbia River', 'Salish Sea', 'Northern California Current Large Marine Ecosystem (CCLME)', 'Puget Sound', and 'Pacific Northwest'. Papers, theses, and reports containing quantitative frequency of occurrence (% FO) data with known sample sizes specifically referring to the 4 stocks of Pacific Harbor Seals (Oregon-Washington Coastal, Hood Canal, Southern Puget Sound, and Washington Northern Inland Waters) in the northern CCLME, including the Salish Sea, Oregon, Washington, and the Columbia River were collected. Methodologies included otolith and multi-part hardparts analysis of prey in scat, and examination of stomach contents. Authors of unpublished or unavailable data were contacted for permission to include data. Non-peer reviewed sources were included if they contained data that were not represented through peer-reviewed sources. Because of the variety of different methods reviewed, data were not weighted or corrected for possible bias, but rather additively reported by % FO.

Results were compiled in Microsoft Excel ([C] Microsoft Corporation). All available data pertinent to the review were recorded: current common name, scientific name (genus and species), order, family, marine zonation (Froese and Pauly 2012), location collected, season, year, sample size, and % FO. All prey species were standardized to their currently accepted scientific classification and spelling. When papers classified prey items to their nearest taxonomic groupings (including class, order, family, genus, species, subphylum or group within a subphylum such as 'shrimp'), this grouping was retained as it was presented in the literature.

In order to obtain and compare total overall FO in all samples in = 13,088), the total number of occurrences in each study (S) was calculated:

S = (n * FO)/100

where n = the number of samples per study, and FO = the frequency of occurrence reported in the study. The total frequency of occurrence ([SIGMA]FO) per prey type for all studies combined was calculated as:

[SIGMA]FO = [SIGMA]S/N * 100

where [SIGMA]S = the total occurrences per species, and N = the total number of samples in all studies combined. If data occurred in more than 1 paper, it was only included once overall.

In some cases where prey were so prevalent that they led to a % FO >100% (for example demersal fishes in Oregon equaled 150% of FO, meaning that scats on average contained 1.5 various demersal fish species), a percent composition (C) value was calculated which represented the total percentage of all identifiable scat remains that consisted of a single group or species. Percent composition was calculated as:

C= [??]/N * 100

where [??] represents the total number of occurrences (identifiable remains) within that region, or overall. Percent composition is a proportion additive up to 100%. Most results in this paper are presented as % FO.

Prey data were divided between established stocks of Pacific Harbor Seals in the northern CCLME, and compared overall. Data were also compiled per location (Oregon, Washington, Columbia River), and by season. Seasonal values were grouped by winter-spring and summer-fall due to availability of data. Prevalence of salmon predation across regions was also reported.

RESULTS

The results of the review yielded 48 papers, reports, or theses that were directly relevant to Harbor Seal foraging for their descriptions of spatial behavior, quantitative and qualitative dietary analysis, or examination of potential fisheries interactions within the northern CCLME. Of the papers examined, 16 contained detailed, quantitative information on dietary composition primarily through FO in fecal hard-parts analysis (Table 1). Percent frequency of occurrence, or % FO, is the relative proportions of scat samples from all samples gathered that contain an identifiable type or species of prey. Two of the papers found, Brown (1980) and Lance and Jeffries (2007), contained data that were duplicated in other publications already being utilized and were not included in the quantitative analysis. The remaining sources (Table 2) included studies describing Harbor Seal behavior by visual observation or alternative measures of prey, captive dietary studies, spatial telemetry data, technical reports assessing and summarizing Harbor Seal predation on salmonids and other commercially-important fish species, a modeled feeding experiment, and genetic or alternative methods for identifying Harbor Seal dietary composition.

Overall

The summed utilizable sample size from all papers equaled 13,088, consisting of 12,993 scats and 95 stomachs with identifiable remains in inland and marine locations (Scheffer and Sperry 1931; Roffe and Mate 1984) (Fig. 1). All prey species reported in the reviewed literature and used in this analysis are listed in the appendix. Of the prey orders representing over 20% FO, gadiform fishes were the primary-occurring prey species (FO = 51.85%), followed by Clupeiformes (51.52%) and perciform fishes (23.72%). Families of fish present in more than 20% of scats included Clupeidae (44.05%), Merlucciidae (35.20%), and Salmonidae (20.47%). The species identified above 10% FO included North Pacific Hake (Merluccius productus), Pacific Herring (Clupea pallasii), and Shiner Perch (Cymatogaster aggregata) (Table 3). Prey species were primarily categorized as Demersal (52.56%), followed by Pelagic-Neretic (46.14%) and Pelagic-Oceanic (35.34%), suggesting a high rate of bottom foraging. Salmonids were present in 23.74% of scats overall, 3.73% of these being reported as juvenile fish. Almost all salmon reported were unidentified to the species level.

Oregon-Washington Coastal Stock

For Harbor Seals of the Oregon-Washington Coastal Stock, a total of 3960 scats or stomachs contained identifiable remains. Seals consumed primarily fish of the orders Pleuronectiformes (FO = 50.32%) and Clupeiformes (48.72%). The taxonomic families present in >20% of samples included Pleuronectidae (60.80%), Clupeidae (36.18%), Osmeridae (25.57%), and Cottidae (21.31%). Prey identified to the species level that occurred in >10% of scats included Pacific Herring, Pacific Staghorn Sculpin (Leptocottus armatus), Pacific Tomcod (Microgadus proximus), North Pacific Hake, Californian Anchovy (Engraulis mordax), Eulachon (T. pacificus), and Shiner Perch (Table 3).

Dietary composition from the Coastal stock consisted heavily of Demersal species (109.56% FO, or 53.15% composition). Pelagic-Neritic prey were also present in more than half of samples (56.73% FO). Coastal Harbor Seal diet consisted primarily of schooling fish species. There was also significant predation on Pacific Staghorn Sculpin, likely due to nearshore exploitation of a highly-available nearshore resource associated with salmonids (McCabe and others 1983). Salmonid species occurred in 9.99% of samples overall, most of which were not identified to species, and 2.88% of which were listed as juveniles.

Southern Puget Sound Stock

The Southern Puget Sound stock of Pacific Harbor Seals was the least-represented stock in the collated studies, with a total sample size of 101 scats collected at Gertrude Island in 1979 (Everitt and others 1981). Sixteen prey species or genera from 9 taxonomic families in 6 orders were identified. Gadiformes was the only prey order represented at >20% (61.38% FO). The family Merlucciidae was present in 56.16% of scats, and the species occurring in >10% of samples included North Pacific Hake (56.12%) and the Plainfin Midshipman (Porichthys notatus) (13.88%). Notably, no salmon remains were found in this region, which could be due to low sample size or geographic location.

Hood Canal Stock

The Hood Canal stock of Harbor Seals predominantly consumed gadiform fishes (64.59%), clupeiform fishes (50.89%), and salmoniform fishes (30.54% adult or unspecified, 3.74% juvenile) out of a total sample size of 7235 scats or stomachs. There were a total of 68 species or genera identified from 36 families and 22 orders, as well as 3 groups not specified to order classification (Cephalopoda, Gastropoda, Crustacea). Families of prey present in >20% of scats included Merlucciidae (53.56%), Clupeidae (46.52%), and Salmonidae (30.54%). Prey identified to the species level that composed >10% of the diet were North Pacific Hake (53.56% FO) and Pacific Herring (34.29%). Prey could be categorized as Pelagic-Oceanic (53.75%), Pelagic-Neritic (38.67%), and Demersal (20.77%). The Hood Canal Stock had the highest frequency of occurrence (34.27%) of salmonids in scat of all groups studied, with 2.86% being identified as juvenile fish. Lance and Jeffries (2009a) and Lance and others (2012) used multi-part analyses, and Scheffer and Sperry (1931) used stomach content analysis, which were potentially more successful at revealing salmon in the diet than did otolith-specific studies.

Northern Inland Waters Stock

The Northern Inland Waters Stock of Harbor Seals was represented by 1792 scat samples; 64.06% of these contained clupeiform fishes, 47.04% contained perciform fishes, 44.68% contained gadiform fishes, and 21.23% contained scorpaeniform fishes. There were 62 prey species or genera present from 43 families and 27 orders. The only families representing >20% FO were Clupeidae (53.71%) and Gadidae (38.39%). Prey identified to species at >10% FO were Pacific Herring, Pacific Sand Lance (Ammodytes hexapte rus), Shiner Perch, Alaska Pollock (Theragra chalcogramma), Californian Anchovy, and Three-spined Stickleback (Gasterosteus aculeatus) (Table 3). Prey occurring in >20% of scats were 56.66% Demersal, 55.7% Pelagic-Neritic, and 54.91% Benthopelagic.

Prey Composition by Season

A majority of samples (n = 10,026) were collected in summer and fall, most likely to coincide with seasonal salmonid abundance (Fig. 2). The remainder of samples were collected in winter and spring in = 2164), or throughout the year or not defined (n = 898). In summer-fall, of 32 orders of prey identified, Gadiformes predominated (54.26% FO), followed by Clupeiformes (51.3%), Salmoniformes (24.96%), and Perciformes (22.09%) (Table 4). Prey species were primarily Demersal (48.19% FO), Pelagic-Neritic (43.63%), or Pelagic-Oceanic (41.71%). In winterspring, of 28 orders identified, Clupeiformes was most prevalent in the diet (56.62% FO), followed by Gadiformes (48.74%), Perciformes (29.67%), Pleuronectiformes (24%), and Scorpaeniformes (22.42%). As in summer-fall, winter-spring prey occurring in >20% of scats were predominantly Demersal (63.57%), followed by Pelagic Neritic (55.97%), Benthopelagic (28.97%), and PelagicOceanic (20.34%). In winter-spring, salmonids were present in 13.4% of samples, and in summer-fall this percent more than doubled (28.49%).

Notable Results by State

Harbor Seal habitat in Oregon consists exclusively of coastal bays and riverine systems, and is considered part of the Oregon-Washington Coastal stock. The diet of Oregon seals consisted heavily of pleuronectid fish, which occurred in 92.84% of scats or stomachs analyzed with identifiable remains. Demersal fish consisted of 151.80% FO or 58.77% by composition, highlighting bottom foraging and consumption of pleuronectids. Prey by FO were identified as 37.89% Pelagic-Neritic. Out of 1211 samples, seals in Oregon consumed prey from 21 taxonomic orders, 35 families (29 of which were teleost fish), and 67 prey identified to the species or genus level. Seals in Oregon consumed 6 families of non-teleost prey, including Myxinidae, Octopodidae, Rajidae, Loliginidae, Cancridae, and Crangonidae. Salmonid fish occurred in 13.3% of scats collected. In one instance, at a collection site in the upper Alsea River (Wright and others 2007), salmonids were present in 50% of samples collected (n = 6).

Washington State's overall sample size (n = 10,070) was composed primarily of samples collected in non-coastal locations (86%), representing the Hood Canal, Northern Inland Waters, and Southern Puget Sound stocks (Fig. 3). The most predominant prey by % FO were gadiform fishes (58.18%). Consumption of salmonids was relatively high (27.8%), with 24.07% identified as adults or unspecified, and 3.73% as juveniles. Of 36 orders identified, only 18 were teleost fishes. Non-teleost prey consumed included cephalopods, crustaceans, rajiform fish, hagfish or lamprey, squaliform or elasmobranch fish (such as Pacific Spiny Dogfish, Squalus suckleyi), gastropods, polychaetes, bivalves, and instances of the consumption of mammals or birds (Luxa and Acevedo-Gutierrez 2013). It is likely that some of these were secondarily consumed, but were included in the analysis as they overall may have contributed to daily caloric intake. Consumption of an aquatic bird (Harlequin Duck, Histrionicus histrionicus) was also visually observed by Tallman and others (2004) in the San Juan Islands. In total, 107 unique prey were identified to the species or genus level. Prey in Washington were most commonly Pelagic-Neritic (39.75% FO), Pelagic-Oceanic (38.89%), or Demersal (32.62%).

Samples with identifiable remains collected in Columbia River locations numbered 1821, and prey largely consisted of clupeiform fishes (57.24% FO). Overall, 25 taxonomic families of prey from 16 orders composed the diet. Nine of the 16 orders of prey represented teleost fish, but crustaceans, lamprey, hagfish, and cephalopods were also consumed. Clupeid fishes occurred at 44.97% by FO, followed by 24.95% pleuronectids, 24.57% osmerids, and 22.57% cottids. Salmon were found to occur in a total of 11.4% of scats, with 5.17% of these identified as adults or unspecified, and 6.22% as juveniles. Lamprey species occurred in 17.13% of collected samples.

DISCUSSION

This literature review examined Pacific Harbor Seal diet across the northern CCLME by stock and geographic boundary, and contained information synthesized from a literature search of peer-reviewed literature, reports, and theses containing dietary information by frequency of occurrence in Harbor Seal scats and stomach. Overall, more than 13,088 scat or stomach samples contained 37 orders, 62 families, and 121 identified genera or species of prey. These prey items primarily consisted of teleost fishes, but also included a number of invertebrates as well as mammals and birds, demonstrating the broad dietary niche of the Pacific Harbor Seal in the areas examined. Coastal stocks of Pacific Harbor Seals largely consumed pleuronectid or clupeiform fishes, while the diet of the inland stocks of seals also consisted largely of perciform, gadiform, salmoniform, and scorpaeniform fishes. Much of the diet of Harbor Seals is largely dependent on what is seasonally abundant or available (Tollit and others 1997a; Middlemas and others 2006); however, this pattern may not always be apparent without consideration of multiple factors (Thomas and others 2011).

Hard-parts-based quantitative dietary analysis, as conducted within a majority of the studies presented, is not without inherent bias (Helm 1984; Cottrell and others 1996; Tollit and others 1997b; Bowen 2000; Browne and others 2002; Laake and others 2002; Arim and Naya 2003; Deagle and Tollit 2007; Phillips and Harvey 2009). However, because of the wide historical availability of this type of data for pinnipeds, it can remain an informative method for describing prey composition and species of interest across regions. Estimation of sample representation of the overall seal population over time is difficult due to logistics of sampling (Helm 1984) and spatio-temporal changes in predator-prey dynamics. According to Trites and Joy (2005), a suggested minimum sample size of 94 Harbor Seal scat samples is required to distinguish moderate effects between areas or time periods in dietary studies. All but 2 studies in this review (Scheffer and Sperry 1931; Roffe and Mate 1984) satisfied this criterion; however, the former represented a unique study site, and the latter represented the earliest available study in this review's regions of interest.

The rate of consumption of salmonids by pinnipeds and other marine mammal predators is of long-term management interest (Adams and others 2016). Most studies contained in this review were designed to estimate the prevalence of Harbor Seal consumption of salmonids. Therefore, there may be an inherent seasonal or regional bias for salmonids or prey associated with salmonids during specific times of year (McCabe and others 1983). Estimating salmonid composition of diet is especially difficult, in part because seals often do not consume the head of large adult salmonids, precluding otolith analysis (Everitt and others 1981). Additionally, without the benefit of genetic methods, it can be difficult or impossible to identify salmonid prey to the species level (Lance and others 2012). Overall, of 23.74% FO of salmon present in scat or stomach samples, 20% were categorized specifically as adults. Juveniles could potentially be under-reported, as the bones of smaller fish may be completely digested or difficult to identify in scat analysis. Of potential significance is the consumption of prey species that are also predators of juvenile salmon, namely lamprey species. In the Columbia River studies, 11.4% of scats contained salmonid remains, while 17.13% of scats contained remains of lamprey, suggesting a more complex ecological interaction than can be determined by single prey-focused consumption studies. Location is another important aspect to consider, as demonstrated by Wright and others (2007). Fifty percent (n = 6) of scats collected at the upriver haul-out site slightly more than 2 km up the Alsea River contained salmonid remains, while only 8% (n = 111) of scats collected at the mouth of the Alsea River (the 'lower' haul-out site) contained salmonid remains. Additional studies with larger sample sizes could further illuminate these findings.

This review was predominated by studies conducted on the Hood Canal, Oregon-Washington Coastal, and Northern Inland Waters stocks, with poorer representation of the Southern Puget Sound stock. More than 75% of representative samples were collected in Washington in the summer-fall season. This highlights the need for further dietary composition studies in Oregon and the Southern Puget Sound. Future randomly-sampled, year-round studies would most likely help to reduce sampling bias in understanding Harbor Seal diet overall.

This comparative review has highlighted the broad spatial and seasonal diversity of Pacific Harbor Seal prey consumption across the northern CCLME over a time span of more than 80 y, including variable regional and seasonal consumption of salmonid species. Most papers used in this review utilized multi-part hard-part analysis of scat samples, and 2 papers reported the stomach contents of seals. Beyond hard-parts analysis, emerging methods have made dietary analysis of pinnipeds more comprehensive, including stable-isotope analysis (Newsome and others 2010), fatty-acid analysis (Bromaghin and others 2013), and genetic methods (Lamont and others 1996; Kvitrud and others 2005). The behavior and diet of marine mammals can be useful indicators of ecosystem function of the coastal marine environment, and collection of strong baseline data sets is essential for better understanding of this dynamic system.

ACKNOWLEDGMENTS

I would like to thank the Oregon State University Hatfield Marine Science Center for support of this project, M Horning of Oregon State University for his mentorship and support through the completion of my Master's degree and continuing support for my PhD program, and my Master's degree committee members D Reese and K Benoit-Bird. I would also like to thank P Gearin (NOAA, Marine Mammal Laboratory) for allowing me to include additional data, as well as my reviewers for their valuable contributions to the improvement of this manuscript.

LITERATURE CITED

ADAMS J, KAPLAN IC, CHASCO B, MARSHALL KN, ACEVEDO-GUTIERREZ A, WARD EJ. 2016. A century of Chinook Salmon consumption by marine mammal predators in the Northeast Pacific Ocean. Ecological Informatics 34:44-51.

ARIM M, NAYA DE. 2003. Pinniped diets inferred from scats: Analysis of biases in prey occurrence. Canadian Journal of Zoology 81:67-73.

BALBAG BS. 2016. A molecular method to quantify sex-specific consumption of Chinook Salmon (Oncorhynchus tshawytscha) by Pacific Harbor Seals (Phoca vitulina ricliardii) using scat [thesis]. Bellingham, WA: Western Washington University. 50 p.

BAYER RD. 1985. Six years of Harbor Seal censusing at Yaquina estuary, Oregon. The Murrelet 66:44-49.

BEACH RJ, GEIGER AC, JEFFRIES SJ, TREACY SD, TROUTMAN BL. 1985. Marine mammals and their interactions with fisheries of the Columbia River and adjacent waters, 1980-1982. Third annual report. Olympia, WA: Washington Department of Wildlife, Wildlife Management Division. NWAFC Processed Report 85-04 316 p.

BEREJIKIAN B, MOORE M, JEFFRIES SJ. 2016. Predator-prey interactions between Harbor Seals and migrating Steelhead Trout smolts revealed by acoustic telemetry. Marine Ecology Progress Series 543:21-35.

BOWEN W. 2000. Reconstruction of pinniped diets: Accounting for complete digestion of otoliths and cephalopod beaks. Canadian Journal of Fisheries and Aquatic Sciences 57:898-905.

BROMAGHIN JF, LANCE MM, ELLIOTT EW, JEFFRIES SJ, ACEVEDO-GUTIERREZ A, KENNISH JM. 2013. New insights into the diets of Harbor Seals (Phoca vitulina) in the Salish Sea revealed by analysis of fatty acid signatures. Fishery Bulletin 111:13-26.

BROWN RF. 1980. Abundance, movements and feeding habits of the Harbor Seal, Phoca vitulim, at Netarts Bay, Oregon [thesis]. Corvallis, OR: Oregon State University. 69 p.

BROWN RF, MATE BR. 1983. Abundance, movements, and feeding habits of Harbor Seals, Phoca vitulina, at Netarts and Tillamook Bays, Oregon. Fishery Bulletin 81:291-301.

BROWN RF, WRIGHT BE, RIEMER SD, LAAKE J. 2005. Trends in abundance and current status of Harbor Seals in Oregon: 1977-2003. Marine Mammal Science 21:657-670.

BROWN RF, JEFFRIES SJ, WRIGHT BE. 2013. Conductivity-temperature-depth profiling of the Columbia River mouth using Pacific Harbor Seals as sampling platforms. Corvallis, OR: Oregon Department of Fish and Wildlife; Lakewood, WA: Washington Department of Fish and Wildlife. DTIC Document. 8 p.

BROWNE P, LAAKE J, DELONG R. 2002. Improving pinniped diet analysis through identification of multiple skeletal structures in fecal samples. Fishery Bulletin 100:423-433.

BURG TM, TRITES AW, SMITH MJ. 1999. Mitochondrial and microsatellite DNA analyses of Harbour Seal population structure in the northeast Pacific Ocean. Canadian Journal of Zoology 77:930-943.

*CALAMBOKIDIS J, BOWMAN K, CARTER S, CUBBAGE J, DAWSON P, FLEISCHNER T, SCHUETT-HAMES J, SKIDMORE J, TAYLOR B, HERMAN S. 1978. Chlorinated hydrocarbon concentrations and the ecology and behavior of Harbor Seals in Washington State waters. Olymbia, WA. Cascadia Research Collective Final Report to the National Science Foundation. 121 p. Available from Cascadia Research Collective, 218 Vi W 4th Ave, Olympia, WA 98501.

CARRETTA JV, FORNEY KA, LOWRY MS, BARLOW J, BAKER J, JOHNSTON D, HANSON B, BROWNELL RL JR, ROBBINS J, MATTILA DK. 2015. US Pacific marine mammal stock assessments: 2014. La Jolla, CA: NOAA Fisheries Southwest Fisheries Center. NOAA-TM-NMFSSWFSC-561. 419 p.

CHECKLEY DM JR, BARTH JA. 2009. Patterns and processes in the California Current System. Progress in Oceanography 83:49-64.

COTTRELL PE, MILLER EH, TRITES AW. 1996. Assessing the use of hard parts in faeces to identify Harbour Seal prey: Results of captive-feeding trials. Canadian Journal of Zoology 74:875-880.

COURBIS S. 2009. Summaries of literature (1960-present): Determinations of prey species (as well as some population and fisheries interaction data) for three pinnnipeds (Pacific Harbor Seal, Phoca vitulina, Steiler (or Northern) Sea Lion, Eumetopias jubatus, and California Sea Lion, Zalophus californianus) on the west coast of North America. Corvallis, OR: Oregon State University Marine Mammal Program. General Technical Report. 373 p.

DEAGLE BE, TOLLIT DJ. 2007. Quantitative analysis of prey DNA in pinniped faeces: Potential to estimate diet composition? Conservation Genetics 8:743747.

DISHMAN DL. 2011. Genetic substructure of Pacific Harbor Seal (Phoca vitulina richardsi) populations along the coasts of Oregon and Washington [thesis]. Portland, OR: Portland State University. 103 p.

EVERITT RD, GEARIN PJ, SKIDMORE JS, DELONG RL. 1981. Prey items of Harbor Seals and California Sea Lions in Puget Sound, Washington. The Murrelet 62:8386.

FROESE R, PAULY D. 2012. FishBase. www.fishbase.org. Accessed 12 July 2016.

* GEARIN FJ, LEHMAN LL, HUGHES KM, COOKE L, DELONG RL, GOSHO ME. 1998. Investigations of pinniped interactions with Lake Ozette Sockeye Salmon in 1998. Preliminary Report. Seattle, WA: National Marine Mammal Laboratory. 57 p. Available from National Marine Mammal Laboratory/AFSC, 7600 Sand Point Way N.E. F/AKC3, Seattle, WA 98115-6349.

GRAYBILL M. 1981. Haul out patterns and diet of Harbor Seals, Phoca vitulina, in Coos County, Oregon [thesis]. Eugene, OR: University of Oregon. 55 p.

GRIGG EK, KLIMLEY AP, ALLEN SG, GREEN DE, ELLIOTTFISK DL, MARKOWITZ H. 2009. Spatial and seasonal relationships between Pacific Harbor Seals (Phoca vitulina richardii) and their prey, at multiple scales. Fishery Bulletin 107:359-372.

HARDEE SE. 2008. Movements and home ranges of Harbor Seals (Phoca vitulina) in the inland waters of the Pacific Northwest [thesis]. Beilingham, WA: Western Washington University. 148 p.

HARVEY J. 1989. Assessment of errors associated with Harbour Seal (Phoca vitulina) faecal sampling. Journal of Zoology 219:101-111.

* HARVEY J, WEISE M. 1997. Impacts of California Sea Lions and Pacific Harbor Seals on salmonids in Monterey Bay, California. Technical Report 97-03. Moss Landing, CA: Moss Landing Marine Labs. Available from Moss Landing Marine Labs, 8272 Moss Landing Rd, Moss Landing, CA 95039.

HELM RC. 1984. Rate of digestion in three species of pinnipeds. Canadian Journal of Zoology 62:1751-1756.

HOWARD S, LANCE MM, JEFFRIES SJ, ACEVEDO-GUTIERREZ A. 2013. Fish consumption by Harbor Seals (Phoca vitulina) in the San Juan Islands, Washington. Fishery Bulletin 111:27.

KVITRUD M, RIEMER S, BROWN R, BELLINGER M, BANKS M. 2005. Pacific Harbor Seals (Phoca vitulina) and salmon: Genetics presents hard numbers for elucidating predator-prey dynamics. Marine Biology 147:1459-1466.

LAAKE JL, BROWNE P, DELONG RL, HUBER HR. 2002. Pinniped diet composition: A comparison of estimation models. Fishery Bulletin 100:434-447.

LAMONT MM, VIDA J, HARVEY JT, JEFFRIES S, BROWN R, HUBER HH, DELONG R, THOMAS WK. 1996. Genetic substructure of the Pacific Harbor Seal (Phoca vitulina richardsi) off Washington, Oregon, and California. Marine Mammal Science 12:402-413.

LANCE MM, JEFFRIES SJ. 2006. Estimating importance of rockfish, Lingcod and other bottomfish in the diet of Harbor Seals in the San Juan Islands. Contract Report to SeaDoc Society Research Agreement no. K004431-22. Olympia, WA: Washington Department of Fish and Wildlife. 20 p.

LANCE MM, JEFFRIES SJ. 2007. Temporal and spatial variability of Harbor Seal diet in the San Juan Island archipelago. Contract Report to SeaDoc Society Research Agreement no. K004431-25. Olympia, WA: Washington Department of Fish and Wildlife. 21 p.

LANCE MM, JEFFRIES SJ. 2009a. Harbor Seal diet in Hood Canal, south Puget Sound and the San Juan Island archipelago. Contract Report to Pacific States Marine Fisheries Commission Job code 497. NOAA Award no. NA05NMF4391151. Olympia, WA: Washington Department of Fish and Wildlife. 30 p.

* LANCE MM, JEFFRIES SJ. 2009b. Short summary of results: Species identification of salmonid bones found in Pacific Harbor Seal fecal samples using micro satellite genetic analysis. Technical Report. Olympia, WA: Washington Department of Fish and Wildlife. Available from Washington Department of Fish and Wildlife, 111 Washington St. SE, Olympia, WA 98501.

LANCE MM, CHANG W-Y, JEFFRIES SJ, PEARSON SF, ACEVEDO-GUTIERREZ A. 2012. Harbor Seal diet in northern Puget Sound: Implications for the recovery of depressed fish stocks. Marine Ecology Progress Series 464:257-271.

LONDON JM. 2006. Harbor Seals in Hood Canal: Predators and prey [dissertation], Seattle, WA: University of Washington. 90 p.

* LONDON JM, LANCE MM, JEFFRIES SJ. 2003. Investigations of Harbor Seal predation on salmonids in Hood Canal, Washington. WDFW Progress Report to PSMFC. Olympia, WA: Washington Department of Fish and Wildlife. Available from Washington Department of Fish and Wildlife, 111 Washington St. SE, Olympia, WA 98501.

LUXA K, ACEVEDO-GUTIERREZ A. 2013. Food habits of Harbor Seals (Phoca vitulina) in two estuaries in the central Salish Sea. Aquatic Mammals 39:10-22.

MCCABE GT, MUIR WD, EMMETT RL, DURKIN JT. 1983. Interrelationships between juvenile salmonids and nonsalmonid fish in the Columbia River Estuary. Fishery Bulletin 81:815-826.

MIDDLEMAS SJ, BARTON TR, ARMSTRONG JD, THOMPSON PM. 2006. Functional and aggregative responses of Harbour Seals to changes in salmonid abundance. Proceedings of the Royal Society B: Biological Sciences 273:193-198.

NEWSOME SD, CLEMENTZ MT, KOCH PL. 2010. Using stable isotope biogeochemistry to study marine mammal ecology. Marine Mammal Science 26:509-572.

* [NMML] NATIONAL MARINE MAMMAL LABORATORY. 1996. Working paper: Biomass consumption estimates of California Sea Lions and Harbor Seals in Puget Sound. Seattle, WA: National Marine Mammal Laboratory. 13 p. Available from Alaska Fisheries Science Center, NMFS, NOAA, 7600 Sand Point Way NE, Seattle, WA 98115.

ORR AJ, BANKS AS, MELLMAN S, HUBER HR, DELONG RL, BROWN RF. 2004. Examination of the foraging habits of Pacific Harbor Seal (Phoca vitulina richardsi) to describe their use of the Umpqua River, Oregon, and their predation on salmonids. Fishery Bulletin 102:108-117.

PETERSON SH, LANCE MM, JEFFRIES S], ACEVEDO-GUTIERREZ A. 2012. Long distance movements and disjunct spatial use of Harbor Seals (Phoca vitulina) in the inland waters of the Pacific Northwest. Plos One 7(6):e39046.

PHILLIPS EM, HARVEY JT. 2009. A captive feeding study with the Pacific Harbor Seal (Phoca vitulina richardii): Implications for scat analysis. Marine Mammal Science 25:373-391.

PURCELL M, MACKEY G, LAHOOD E, HUBER H, PARK L. 2004. Molecular methods for the genetic identification of salmonid prey from Pacific Harbor Seal (Phoca vitulina richardsi) scat. Fishery Bulletin 102:213-220.

* RHYDDERCH JG, LUNDRIGAN TA, MORAN F, HUBER HR, PARK LR. 2004. Progress report on pinniped and salmonid interactions in the Columbia River: Genetic discrimination of Chinook Salmon stocks. NMML Progress Report. Seattle, WA: National Marine Mammal Laboratory. Available from National Marine Mammal Laboratory, AFSC/NOAA, 7600 Sand Point Way N.E. F/AKC3, Seattle, WA 98115-6349.

RIEMER SD, BROWN RE 1997. Prey of pinnipeds at selected sites in Oregon identified by scat (fecal) analysis, 1983-1996. Wildlife Diversity Program Technical Report no. 95-6-01. Salem, OR: Oregon Department of Fish and Wildlife. 16 p.

ROFFE TJ, MATE BR. 1984. Abundances and feeding habits of pinnipeds in the Rogue River, Oregon. The Journal of Wildlife Management 48:1262-1274.

SCHEFFER TH, SPERRY CC. 1931. Food habits of the Pacific Harbor Seal, Phoca richardii. Journal of Mammalogy 12:214-226.

SCORDINO J. 2010. West coast pinniped program investigations on California Sea Lion and Pacific Harbor Seal impacts on salmonids and other fishery resources. Report to the Pacific States Marine Fisheries Commission. Portland, OR: NOAA/NMFS/Pacific States Marine Fisheries Commission. 102 p.

TALLMAN J, SULLIVAN C, LEWIS J. 2004. Harbor Seal (Phoca vitulina) predation on a male Harlequin Duck (Histrionicus histrionicus). Northwestern Naturalist 85:31-32.

THOMAS AC, LANCE MM, JEFFRIES SJ, MINER BG, ACEVEDO-GUTIERREZ A. 2011. Harbor Seal foraging response to a seasonal resource pulse, spawning Pacific Herring. Marine Ecology-Progress Series 441:225-239.

TOLLIT DJ, GREENSTREET SPR, THOMPSON PM. 1997a. Prey selection by Harbour Seals, Phoca vitulina, in relation to variations in prey abundance. Canadian Journal of Zoology 75:1508-1518.

TOLLIT D, STEWARD M, THOMPSON P, PIERCE G, SANTOS M, HUGHES S. 1997b. Species and size differences in the digestion of otoliths and beaks: Implications for estimates of pinniped diet composition. Canadian Journal of Fisheries and Aquatic Sciences 54:105-119.

TRC AND COMES. 2012. Oregon commercial fishing industry economic contributions in 2011 and outlook for 2012. Briefing report prepared for Oregon Department of Fisheries and Wildlife. Corvallis OR: Oregon State University, Coastal Oregon Marine Experiment Station. 22 p.

TRITES AW, JOY R. 2005. Dietary analysis from fecal samples: How many scats are enough? Journal of Mammalogy 86:704-712.

[USDC] US DEPARTMENT OF COMMERCE. 1999. Report to Congress: Impacts of California Sea Lions and Pacific Harbor Seals on salmonids and west coast ecosystems. Washington, DC: Department of Commerce, National Oceanic and Atmospheric Administration. 18 p.

WILSON K, LANCE M, JEFFRIES S, ACEVEDO-GUTIERREZ A. 2014. Fine-scale variability in Harbor Seal foraging behavior. PloS one 9:e92838.

WRIGHT BE, RIEMER SD, BROWN RF, OUGZIN AM, BUCKLIN KA. 2007. Assessment of Sarbor Seal predation on adult salmonids in a Pacific Northwest estuary. Ecological Applications 17:338-351.

ZAMON JE. 2001. Seal predation on salmon and forage fish schools as a function of tidal currents in the San Juan Islands, Washington, USA. Fisheries Oceanography 10:353-366.

Submitted 14 January 2016, accepted 24 August 2016. Corresponding Editor: Robert Hoffman.
APPENDIX. Prey species of Pacific Harbor Seals reported in the
reviewed literature. C = Oregon-Washington Coastal; HC = Hood Canal;
SP = Southern Puget Sound; NI = Washington Northern Inland Waters.

Scientific Name                    Common Name

Allosmerus elongatus               Whitebait Smelt
Alosa sapidissima                  American Shad
Ammodytes hexapterus               Pacific Sand Lance
Amphistichus rhodoterus            Redtail Surfperch
Anarrhichthys ocellatus            Wolf-eel
Anoplopoma fimbria                 Sablefish
Argentinid spp                     Herring Smelt
Artedius spp                       Sculpin
Atheresthes stomias                Arrow-tooth Rounder
Berryteuthis magister              Magister Armhook Squid
Berryteuthis spp                   Armhook Squid
Brachyistius frenatus              Kelp Perch
Cancer spp                         Cancer Crab
Chilara taylori                    Spotted Cusk-eel
Chitonotus pugetensis              Roughback Sculpin
Citharichthys sordidus             Pacific Sanddab
Citharichthys spp                  Sanddab
Citharichthys stigmaeus            Speckled Sanddab
Clevelatidia ios                   Arrow Goby
Clupea pallasii                    Pacific Herring
Crangon spp                        Crangon Shrimp
Cryptacanthodes giganteus          Giant Wrymouth
Cymatogaster aggregata             Shiner Perch
Diaphus theta                      California Headlightfish
Doryteuthis opalescens             Opalescent Inshore Squid
Embiotoca lateralis                Striped Seaperch
Engraulis mordax                   Californian Anchovy
Enophrys bison                     Buffalo Sculpin
Enophrys spp                       Enophrys Sculpin
Entosphenus tridentatus            Pacific Lamprey
Eopsetta jordani                   Petrale Sole
Eptatretus stoutii                 Pacific Hagfish
Gadus macrocephalus                Pacific Cod
Gasterosteus aculeatus             Three-spined Stickleback
Genyonemus lineatns                White Croaker
Glebocarcinus oregonensis          Pygmy Rock Crab
Glyptocephalus zachirus            Rex Sole
Gonatus onyx                       Clawed Armhook Squid
Gonatus spp                        Gonatus Squid
Hemigrapsus oregonensis            Oregon Shore Crab
Hemilepidotus spinosus             Brown Irish Lord
Hemilepidotus spp                  Irish Lord
Hexagrammos decagrammus            Kelp Greenling
Hippoglossoides elassodon          Flathead Sole
Hydrolagus colliei                 Spotted Ratfish
Hyperprosopon ellipticum           Silver Surfperch
Hypomesus pretiosus                Surf Smelt
Icelinus tenuis                    Spotfin Sculpin
Icelus spp                         Scaled Sculpin
Isopsetta isolepis                 Butter Sole
Lampetra ayresii                   River Lamprey
Lampetra spp                       Lamprey
Lepidogobius lepidus               Bay Goby
Lepidopsetta bilineata             Rock Sole
Leptocottus armatus                Pacific Staghorn Sculpin
Liinanda aspera                    Yellowfin Sole
Loligo spp                         Loligo Squid
Lumpenus lampretaeformis           Snakeblenny
Lumpenus sagitta                   Snake Prickleback
Lycodes pacificus                  Blackbelly Eelpout
Lyopsetta exilis                   Slender Sole
Merluccius productus               North Pacific Hake
Metacarcinus gracilis              Graceful Rock Crab
Metacarcinus magister              Dungeness Crab
Microgadus proximus                Pacific Tomcod
Microstomus pacificus              Dover Sole
Mylocheilus caurinus               Peamouth Chub
Myoxocephalus spp                  Myoxocephalus Sculpin
Nautichthys oculofasciatus         Sailfin Sculpin
Neotrypaea californiensis          Bay Ghost Shrimp
Octopus rubescens                  Pacific Red Octopus
Octopus spp                        Octopus
Oncorhynchus gorbuscha             Pink Salmon
Oncorhynchus keta                  Chum Salmon
Oncorhynchus kisutch               Coho Salmon
Oncorhynchus kisutch (juv)         Coho Salmon (juv)
Oncorhynchus mykiss                Steelhead Salmon
Oncorhynchus nerka                 Sockeye Salmon
Oncorhynchus nerka (juv)           Sockeye Salmon (juv)
Oncorhynchus spp                   Salmon spp
Oncorhynchus spp (juv)             Oncorhychus Salmon (juv)
Oncorhynchus tshawytscha           Chinook Salmon
Oncorhynchus tshaivytscha (juv)    Chinook Salmon (juv)
Ophiodon elongatus                 Lingcod
Pagurus spp                        Hermit Crab
Pandalus danae                     Dock Shrimp
Parophrys vetulus                  English Sole
Peprilus simillimus                Pacific Pompano
Petrolisthes cinctipes             Flat Porcelain Crab
Petrolisthes eriomerus             Flattop Crab
Phanerodon furcatus                White Seaperch
Pholis orna ta                     Saddleback Gunnel
Pinnixa schmitti                   Schmitt Pea Crab
Platichthys stellatus              Starry Hounder
Plectobranchus evides              Bluebarred Prickleback
Pleuronichthys coenosus            C-O Sole
Porichthys notatus                 Plainfin Midshipman
Poroclinus rothrocki               Whitebarred Prickleback
Psettichthys melanostictus         Pacific Sand Sole
Ptychocheilus oregonensis          Northern Pikeminnow
Radulinus asprellus                Slim Sculpin
Rhacochilus vacca                  Pile Perch
Rhinogobiops nicholsii             Blackeye Goby
Ronquilus jordani                  Northern Ronquil
Sardinops sagax                    Pacific Sardine
Scomber japonicus                  Pacific Mackerel
Scorpaenichthys marmoratus         Cabezon
Scorpaenidae spp                   Scorpionfish
Spirinchus starksi                 Night Smelt
Spirinchus thaleichthys            Longfin Smelt
Squalus suckleyi                   Pacific Spiny Dogfish
Stenobrachius leucopsarus          Northern Lampfish
Syngnathus leptorhynchus           Bay Pipefish
Thaleichthys pacificus             Eulachon
Theragra chalcogramma              Alaska Pollock
Trachurus symmetricus              Pacific Jack Mackerel
Trichodon trichodon                Pacific Sandfish
Trichotropis spp                   Cap Snail
Upogebia pugettensis               Blue Mud Shrimp
Yoldia myalis                      Comb Yoldia Clam

Scientific Name                    Order

Allosmerus elongatus               Osmeriformes
Alosa sapidissima                  Clupeiformes
Ammodytes hexapterus               Perciformes
Amphistichus rhodoterus            Perciformes
Anarrhichthys ocellatus            Perciformes
Anoplopoma fimbria                 Scorpaeniformes
Argentinid spp                     Argen tiniformes
Artedius spp                       Scorpaeniformes
Atheresthes stomias                Pleuronectiformes
Berryteuthis magister              Teuthida
Berryteuthis spp                   Teuthida
Brachyistius frenatus              Perciformes
Cancer spp                         Decapoda
Chilara taylori                    Ophidiiformes
Chitonotus pugetensis              Scorpaeniformes
Citharichthys sordidus             Pleuronectiformes
Citharichthys spp                  Pleuronectiformes
Citharichthys stigmaeus            Pleuronectiformes
Clevelatidia ios                   Perciformes
Clupea pallasii                    Clupeiformes
Crangon spp                        Decapoda
Cryptacanthodes giganteus          Perciformes
Cymatogaster aggregata             Perciformes
Diaphus theta                      Myctophiformes
Doryteuthis opalescens             Myopsida
Embiotoca lateralis                Perciformes
Engraulis mordax                   Clupeiformes
Enophrys bison                     Scorpaeniformes
Enophrys spp                       Scorpaeniformes
Entosphenus tridentatus            Petromyzontiformes
Eopsetta jordani                   Pleuronectiformes
Eptatretus stoutii                 Myxiniformes
Gadus macrocephalus                Gadiformes
Gasterosteus aculeatus             Gasterosteiformes
Genyonemus lineatns                Perciformes
Glebocarcinus oregonensis          Decapoda
Glyptocephalus zachirus            Pleuronectiformes
Gonatus onyx                       Teuthida
Gonatus spp                        Teuthida
Hemigrapsus oregonensis            Decapoda
Hemilepidotus spinosus             Scorpaeniformes
Hemilepidotus spp                  Scorpaeniformes
Hexagrammos decagrammus            Scorpaeniformes
Hippoglossoides elassodon          Pleuronectiformes
Hydrolagus colliei                 Chimaeriformes
Hyperprosopon ellipticum           Perciformes
Hypomesus pretiosus                Osmeriformes
Icelinus tenuis                    Scorpaeniformes
Icelus spp                         Scorpaeniformes
Isopsetta isolepis                 Pleuronectiformes
Lampetra ayresii                   Petromyzontiformes
Lampetra spp                       Petromyzontiformes
Lepidogobius lepidus               Perciformes
Lepidopsetta bilineata             Pleuronectiformes
Leptocottus armatus                Scorpaeniformes
Liinanda aspera                    Pleuronectiformes
Loligo spp                         Teuthida
Lumpenus lampretaeformis           Perciformes
Lumpenus sagitta                   Perciformes
Lycodes pacificus                  Perciformes
Lyopsetta exilis                   Pleuronectiformes
Merluccius productus               Gadiformes
Metacarcinus gracilis              Decapoda
Metacarcinus magister              Decapoda
Microgadus proximus                Gadiformes
Microstomus pacificus              Pleuronectiformes
Mylocheilus caurinus               Cypriniformes
Myoxocephalus spp                  Scorpaeniformes
Nautichthys oculofasciatus         Scorpaeniformes
Neotrypaea californiensis          Decapoda
Octopus rubescens                  Octopoda
Octopus spp                        Octopoda
Oncorhynchus gorbuscha             Salmoniformes
Oncorhynchus keta                  Salmoniformes
Oncorhynchus kisutch               Salmoniformes
Oncorhynchus kisutch (juv)         Salmoniformes (juv)
Oncorhynchus mykiss                Salmoniformes
Oncorhynchus nerka                 Salmoniformes
Oncorhynchus nerka (juv)           Salmoniformes (juv)
Oncorhynchus spp                   Salmoniformes
Oncorhynchus spp (juv)             Salmoniformes (juv)
Oncorhynchus tshawytscha           Salmoniformes
Oncorhynchus tshaivytscha (juv)    Salmoniformes (juv)
Ophiodon elongatus                 Scorpaeniformes
Pagurus spp                        Decapoda
Pandalus danae                     Decapoda
Parophrys vetulus                  Pleuronectiformes
Peprilus simillimus                Perciformes
Petrolisthes cinctipes             Decapoda
Petrolisthes eriomerus             Decapoda
Phanerodon furcatus                Perciformes
Pholis orna ta                     Perciformes
Pinnixa schmitti                   Decapoda
Platichthys stellatus              Pleuronectiformes
Plectobranchus evides              Perciformes
Pleuronichthys coenosus            Pleuronectiformes
Porichthys notatus                 Batrachoidiformes
Poroclinus rothrocki               Perciformes
Psettichthys melanostictus         Pleuronectiformes
Ptychocheilus oregonensis          Cypriniformes
Radulinus asprellus                Scorpaeniformes
Rhacochilus vacca                  Perciformes
Rhinogobiops nicholsii             Perciformes
Ronquilus jordani                  Perciformes
Sardinops sagax                    Clupeiformes
Scomber japonicus                  Perciformes
Scorpaenichthys marmoratus         Scorpaeniformes
Scorpaenidae spp                   Scorpaeniformes
Spirinchus starksi                 Osmeriformes
Spirinchus thaleichthys            Osmeriformes
Squalus suckleyi                   Squaliformes
Stenobrachius leucopsarus          Myctophiformes
Syngnathus leptorhynchus           Syngnathiformes
Thaleichthys pacificus             Osmeriformes
Theragra chalcogramma              Gadiformes
Trachurus symmetricus              Perciformes
Trichodon trichodon                Perciformes
Trichotropis spp                   Class: Gastropoda
Upogebia pugettensis               Decapoda
Yoldia myalis                      Nuculoida

Scientific Name                    Family              Stock

Allosmerus elongatus               Osmeridae           C
Alosa sapidissima                  Clupeidae           C,HC,NI
Ammodytes hexapterus               Ammodytidae         C,HC,NI
Amphistichus rhodoterus            Embiotocidae        C
Anarrhichthys ocellatus            Anarhichadidae      HC,NI
Anoplopoma fimbria                 Anoplopomatidae     C,NI
Argentinid spp                     Argentinidae        HC,NI
Artedius spp                       Cottidae            C
Atheresthes stomias                Pleuronectidae      C,NI
Berryteuthis magister              Gonatidae           HC,NI
Berryteuthis spp                   Gonatidae           HC
Brachyistius frenatus              Embiotocidae        C
Cancer spp                         Cancridae           C
Chilara taylori                    Ophidiidae          c
Chitonotus pugetensis              Cottidae            C,HC
Citharichthys sordidus             Paralichthyidae     C,NI
Citharichthys spp                  Paralichthyidae     C
Citharichthys stigmaeus            Paralichthyidae     C,SP,NI
Clevelatidia ios                   Gobiidae            C
Clupea pallasii                    Clupeidae           C,SP,HC,NI
Crangon spp                        Crangonidae         C,HC
Cryptacanthodes giganteus          Cryptacanthodidae   HC
Cymatogaster aggregata             Embiotocidae        C,SP,HC,NI
Diaphus theta                      Myctophidae         HC,NI
Doryteuthis opalescens             Loliginidae         C,HC,NI
Embiotoca lateralis                Embiotocidae        C
Engraulis mordax                   Engraulidae         C,HC,NI
Enophrys bison                     Cottidae            C,HC
Enophrys spp                       Cottidae            SP,NI
Entosphenus tridentatus            Petromyzontidae     C,HC,NI
Eopsetta jordani                   Pleuronectidae      C,NI
Eptatretus stoutii                 Myxinidae           C
Gadus macrocephalus                Gadidae             C,HC,NI
Gasterosteus aculeatus             Gasterosteidae      C,HC,NI
Genyonemus lineatns                Sciaenidae          C,NI
Glebocarcinus oregonensis          Cancridae           HC
Glyptocephalus zachirus            Pleuronectidae      C,SP,HC,NI
Gonatus onyx                       Gonatidae           HC
Gonatus spp                        Gonatidae           HC,NI
Hemigrapsus oregonensis            Varunidae           HC
Hemilepidotus spinosus             Cottidae            C
Hemilepidotus spp                  Cottidae            C,HC,NI
Hexagrammos decagrammus            Hexagrammidae       C,NI
Hippoglossoides elassodon          Pleuronectidae      C,NI
Hydrolagus colliei                 Chimaeridae         HC
Hyperprosopon ellipticum           Embiotocidae        C
Hypomesus pretiosus                Osmeridae           C,HC,NI
Icelinus tenuis                    Cottidae            C
Icelus spp                         Cottidae            C,HC
Isopsetta isolepis                 Pleuronectidae      C,NI
Lampetra ayresii                   Petromyzontidae     C,NI
Lampetra spp                       Petromyzontidae     C
Lepidogobius lepidus               Gobiidae            c
Lepidopsetta bilineata             Pleuronectidae      C,NI
Leptocottus armatus                Cottidae            C, SP, HC, NI
Liinanda aspera                    Pleuronectidae      C
Loligo spp                         Loliginidae         C,HC
Lumpenus lampretaeformis           Stichaeidae         HC
Lumpenus sagitta                   Stichaeidae         C,NI
Lycodes pacificus                  Zoarcidae           NI
Lyopsetta exilis                   Pleuronectidae      C,SP,HC,NI
Merluccius productus               Merlucciidae        C,SP,HC,NI
Metacarcinus gracilis              Cancridae           HC
Metacarcinus magister              Cancridae           HC
Microgadus proximus                Gadidae             C,SP,HC,NI
Microstomus pacificus              Pleuronectidae      C,SP,HC,NI
Mylocheilus caurinus               Cyprinidae          C
Myoxocephalus spp                  Cottidae            NI
Nautichthys oculofasciatus         Hemitripteridae     NI
Neotrypaea californiensis          Callainassidae      C,HC
Octopus rubescens                  Octopodidae         C,HC,NI
Octopus spp                        Octopodidae         C,HC
Oncorhynchus gorbuscha             Salmonidae          NI
Oncorhynchus keta                  Salmonidae          HC,NI
Oncorhynchus kisutch               Salmonidae          C,HC
Oncorhynchus kisutch (juv)         Salmonidae (juv)    HC
Oncorhynchus mykiss                Salmonidae          C,NI
Oncorhynchus nerka                 Salmonidae          C,HC,NI
Oncorhynchus nerka (juv)           Salmonidae (juv)    HC
Oncorhynchus spp                   Salmonidae          C,HC
Oncorhynchus spp (juv)             Salmonidae (juv)    C
Oncorhynchus tshawytscha           Salmonidae          C,HC,NI
Oncorhynchus tshaivytscha (juv)    Salmonidae (juv)    HC, NI
Ophiodon elongatus                 Hexagrammidae       C,HC,NI
Pagurus spp                        Paguridae           HC
Pandalus danae                     Pandalidae          HC
Parophrys vetulus                  Pleuronectidae      C,SP,HC,NI
Peprilus simillimus                Stromateidae        C
Petrolisthes cinctipes             Porcellanidae       HC
Petrolisthes eriomerus             Porcellanidae       HC
Phanerodon furcatus                Embiotocidae        C,SP
Pholis orna ta                     Pholidae            C
Pinnixa schmitti                   Pinnotheridae       HC
Platichthys stellatus              Pleuronectidae      C,HC,NI
Plectobranchus evides              Stichaeidae         C
Pleuronichthys coenosus            Pleuronectidae      NI
Porichthys notatus                 Batrachoididae      C,SP,HC,NI
Poroclinus rothrocki               Stichaeidae         C
Psettichthys melanostictus         Pleuronectidae      C,HC,NI
Ptychocheilus oregonensis          Cyprinidae          NI
Radulinus asprellus                Cottidae            C
Rhacochilus vacca                  Embiotocidae        C,SP,HC,NI
Rhinogobiops nicholsii             Gobiidae            C
Ronquilus jordani                  Bathymasteridae     C,HC
Sardinops sagax                    Clupeidae           C,HC,NI
Scomber japonicus                  Scombridae          C,HC,NI
Scorpaenichthys marmoratus         Cottidae            C
Scorpaenidae spp                   Scorpaenidae        C,NI
Spirinchus starksi                 Osmeridae           C
Spirinchus thaleichthys            Osmeridae           c
Squalus suckleyi                   Squalidae           C,HC,NI
Stenobrachius leucopsarus          Myctophidae         HC,NI
Syngnathus leptorhynchus           Syngnathidae        NI
Thaleichthys pacificus             Osmeridae           C,HC,NI
Theragra chalcogramma              Gadidae             SP,HC,NI
Trachurus symmetricus              Carangidae          C
Trichodon trichodon                Trichodontidae      C,NI
Trichotropis spp                   Capulidae           HC
Upogebia pugettensis               Upogebiidae         HC
Yoldia myalis                      Yoldiidae           HC

Scientific Name                    Region

Allosmerus elongatus               OR,WA,CR
Alosa sapidissima                  OR,WA,CR
Ammodytes hexapterus               OR,WA,CR
Amphistichus rhodoterus            WA,CR
Anarrhichthys ocellatus            WA
Anoplopoma fimbria                 OR,WA,CR
Argentinid spp                     WA
Artedius spp                       OR
Atheresthes stomias                OR,WA
Berryteuthis magister              WA
Berryteuthis spp                   WA
Brachyistius frenatus              WA
Cancer spp                         OR,WA,CR
Chilara taylori                    OR
Chitonotus pugetensis              OR,WA
Citharichthys sordidus             OR,WA,CR
Citharichthys spp                  OR,WA
Citharichthys stigmaeus            OR,WA,CR
Clevelatidia ios                   OR
Clupea pallasii                    OR,WA,CR
Crangon spp                        OR,WA,CR
Cryptacanthodes giganteus          WA
Cymatogaster aggregata             OR,WA,CR
Diaphus theta                      WA
Doryteuthis opalescens             WA
Embiotoca lateralis                OR
Engraulis mordax                   OR,WA,CR
Enophrys bison                     WA
Enophrys spp                       WA
Entosphenus tridentatus            OR,WA,CR
Eopsetta jordani                   OR,WA,CR
Eptatretus stoutii                 OR,WA,CR
Gadus macrocephalus                OR,WA
Gasterosteus aculeatus             OR,WA
Genyonemus lineatns                WA
Glebocarcinus oregonensis          WA
Glyptocephalus zachirus            OR,WA,CR
Gonatus onyx                       WA
Gonatus spp                        WA
Hemigrapsus oregonensis            WA
Hemilepidotus spinosus             WA
Hemilepidotus spp                  OR,WA,CR
Hexagrammos decagrammus            OR,WA
Hippoglossoides elassodon          OR,WA
Hydrolagus colliei                 WA
Hyperprosopon ellipticum           OR
Hypomesus pretiosus                OR,WA,CR
Icelinus tenuis                    WA
Icelus spp                         CR
Isopsetta isolepis                 OR,WA,CR
Lampetra ayresii                   OR,WA,CR
Lampetra spp                       OR,WA,CR
Lepidogobius lepidus               OR,WA
Lepidopsetta bilineata             OR,WA
Leptocottus armatus                OR,WA,CR
Liinanda aspera                    WA
Loligo spp                         OR,WA,CR
Lumpenus lampretaeformis           WA
Lumpenus sagitta                   WA,CR
Lycodes pacificus                  WA
Lyopsetta exilis                   OR,WA
Merluccius productus               OR,WA,CR
Metacarcinus gracilis              WA
Metacarcinus magister              WA
Microgadus proximus                OR,WA,CR
Microstomus pacificus              OR,WA,CR
Mylocheilus caurinus               OR,CR
Myoxocephalus spp                  WA
Nautichthys oculofasciatus         WA
Neotrypaea californiensis          OR,WA,CR
Octopus rubescens                  OR,WA,CR
Octopus spp                        OR,WA
Oncorhynchus gorbuscha             WA
Oncorhynchus keta                  WA
Oncorhynchus kisutch               OR,WA
Oncorhynchus kisutch (juv)         WA
Oncorhynchus mykiss                OR,WA,CR
Oncorhynchus nerka                 WA,CR
Oncorhynchus nerka (juv)           WA
Oncorhynchus spp                   OR,WA
Oncorhynchus spp (juv)             OR
Oncorhynchus tshawytscha           OR,WA
Oncorhynchus tshaivytscha (juv)    WA
Ophiodon elongatus                 OR,WA
Pagurus spp                        WA
Pandalus danae                     WA
Parophrys vetulus                  OR,WA,CR
Peprilus simillimus                WA
Petrolisthes cinctipes             WA
Petrolisthes eriomerus             WA
Phanerodon furcatus                OR,WA
Pholis orna ta                     OR
Pinnixa schmitti                   WA
Platichthys stellatus              OR,WA,CR
Plectobranchus evides              WA
Pleuronichthys coenosus            WA
Porichthys notatus                 WA
Poroclinus rothrocki               OR,WA,CR
Psettichthys melanostictus         OR,WA,CR
Ptychocheilus oregonensis          WA
Radulinus asprellus                OR,CR
Rhacochilus vacca                  OR,WA
Rhinogobiops nicholsii             OR
Ronquilus jordani                  WA
Sardinops sagax                    OR,WA
Scomber japonicus                  OR,WA
Scorpaenichthys marmoratus         OR
Scorpaenidae spp                   WA
Spirinchus starksi                 OR
Spirinchus thaleichthys            OR,WA,CR
Squalus suckleyi                   WA
Stenobrachius leucopsarus          WA
Syngnathus leptorhynchus           WA
Thaleichthys pacificus             OR,WA,CR
Theragra chalcogramma              WA
Trachurus symmetricus              OR,WA
Trichodon trichodon                OR,WA,CR
Trichotropis spp                   WA
Upogebia pugettensis               WA
Yoldia myalis                      WA

TABLE 1. Summary of reviewed papers and methods of identifying
Pacific Harbor Seal prey, listed alphabetically. Stock: WOC =
Washington-Oregon Coastal; SPS = Southern Puget Sound; HC = Hood
Canal; NIW = Northern Inland Waters. Study location: CR = Columbia
River. Evaluation seasons; W = winter; Spr = spring; S = summer; F =
fall; AS = all seasons.

Author(s), year            Study location

Beach and others 1985      Tillamook Bay OR, Grays Harbor
                           WA, Willapa Bay WA,
                           Desdemona Sands CR

Brown and Mate 1983        Netarts Bay, OR

Browne and others 2002     Desdemona Sands, CR

Everitt and others 1981    Protection and Gertrude Islands, WA

Gearin and others 1998     Ozette River, WA

Graybill 1981              Coos Bay, OR

Lance and Jeffries 2009a   Puget Sound, Eastern Bays, San
                           Juan Islands, WA

Lance and others 2012      San Juan Islands, WA

Luxa and Acevedo-          Salish Sea
Guitierrez 2013

Orr and others 2004        Umpqua River, OR

Roffe and Mate 1984        Rogue River, OR

Scheffer and Sperry 1931   Puget Sound, WA

Thomas and others 2011     Protection Island, WA

Wright and others 2007     Alsea River, OR

Author(s), year            Stock(s)   Season      Sampling Year(s)

Beach and others 1985      WOC        AS             1980-1982

Brown and Mate 1983        WOC        S, F           1977-1979

Browne and others 2002     WOC        Spr, S, F      1995-1997

Everitt and others 1981    SPS, NIW   AS             1978-1979

Gearin and others 1998     WOC        Spr, S            1998

Graybill 1981              WOC        AS             1978-1981

Lance and Jeffries 2009a   HC, NIW    AS             1997-2006

Lance and others 2012      HC         AS             2005-2008

Luxa and Acevedo-          NIW        Spr, S, F         2006
Guitierrez 2013

Orr and others 2004        WOC        Spr, F         1997-1998

Roffe and Mate 1984        NIW        AS             1976-1978

Scheffer and Sperry 1931   HC         AS             1927-1930

Thomas and others 2011     NIW        Spr, S            2009

Wright and others 2007     WOC        F                 2002

Author(s), year            Evaluation method

Beach and others 1985      Scat otoliths, teeth, beaks

Brown and Mate 1983        Visual survey, scat
                           otoliths and teeth

Browne and others 2002     Scat bones, teeth,
                           otoliths, beaks

Everitt and others 1981    Scat otoliths

Gearin and others 1998     Scat vertebrae, gill
                           rakers, optic capsules,
                           teeth and mouthparts

Graybill 1981              Scat otoliths, beaks

Lance and Jeffries 2009a   Scat bones, otoliths,
                           beaks

Lance and others 2012      Scat bones, otoliths,
                           beaks, cartilage
Luxa and Acevedo-          Scat otoliths, bones,
Guitierrez 2013            beaks, cartilage

Orr and others 2004        Scat otoliths, beaks,
                           cartilage, bones,
                           statolith

Roffe and Mate 1984        Stomach bones, beaks,
                           otoliths

Scheffer and Sperry 1931   Stomach content analysis

Thomas and others 2011     Scat bone, otolith, beaks

Wright and others 2007     Scat otoliths, beaks, gill
                           rakers, vertebrae,
                           visual survey, genetic
                           analysis

Author(s), year            Samples with remains
                            ([SIGMA] = 10,868)

Beach and others 1985              1086

Brown and Mate 1983                 95

Browne and others 2002             1385

Everitt and others 1981             230

Gearin and others 1998              330

Graybill 1981                       296

Lance and Jeffries 2009a           6796

Lance and others 2012              1683

Luxa and Acevedo-                   198
Guitierrez 2013

Orr and others 2004                 651

Roffe and Mate 1984             14 stomachs

Scheffer and Sperry 1931        81 stomachs

Thomas and others 2011              126

Wright and others 2007              117

TABLE 2. Summary of additional reviewed papers examining Pacific
Harbor Seal behavior or dietary composition in the Northern CCLME
using non-FO methods, listed alphabetically by method.

Category                Author(s), Year         Method (s)

Visual survey or non-   Bayer 1985              Visual survey, radio
FO dietary assessment                           telemetry, captive
                                                assessment of hard
                                                parts scatology

                        Calambokidis and        FO dietary
                        others 1978             consumption with no
                                                total sample size

                        London 2006             Visual survey,
                                                molecular scatology

                        London and others       Visual observation of
                        2003                    predation, molecular
                                                and hard parts
                                                scatology

                        Riemer and Brown 1997   Hard parts scatology

                        Tallman and others      Visual observation of
                        2004                    predation

                        Zamon 2001              Visual observation of
                                                predation

Captive dietary         Cottrell and others     Captive feeding
studies and modeled     1996                    assessment of hard
feeding experiments                             parts scatology
                                                methods

                        Harvey 1989             Captive feeding
                                                assessment of hard
                                                parts scatology
                                                methods

                        Phillips and Harvey     Captive feeding
                        2009                    assessment of hard
                                                parts scatology
                                                methods

                        Trites and Joy 2005     Modeling and
                                                controlled feeding
                                                experiment

Spatial telemetry or    Berejikian and others   Acoustic telemetry
modeling                2016                    assessment of seal-
                                                salmon interactions

                        Brown and others 2013   Marine mammals as
                                                autonomous
                                                environmental
                                                samplers

                        Grigg and others 2009   Satellite telemetry/
                                                scales of predator/
                                                prey interaction

                        Hardee 2008             Satellite telemetry

                        Peterson and others     Satellite telemetry
                        2012

                        Wilson and others       Fine-scale analysis
                        2014                    of foraging behavior

Technical reports and   Carretta and others     Marine mammal stock
summaries               2015                    assessments

                        Courbis 2009            Summary of
                                                literature; pinniped-
                                                fisheries
                                                interactions

                        Harvey and Weise 1997   Technical assessment

                        Scordino 2010           Technical summary

                        USDC 1999               Technical report to
                                                congress

Emerging/alternative    Balbag 2016             Molecular scatology
methods of dietary
assessment              Bromaghin and others    Quantitative fatty
                        2013                    acid signature
                                                analysis

                        Browne and others       Multiple skeletal
                        2002                    structure
                                                identification

                        Howard and others       in scat Bioenergetics
                        2013                    model

                        Laake and others 2002   Comparison of
                                                estimation models

                        Lance and Jeffries      Microsatellite
                        2009b                   analysis of prey in
                                                scat

                        NMML 1996               Biomass consumption
                                                estimation modeling

                        Purcell and others      Molecular scatology
                        2004

                        Rhydderch and others    Genetic
                        2004                    discrimination of
                                                salmonid stocks
                                                subject to pinniped
                                                predation

TABLE 3. Top prey species occurring in: (1) >10% of samples overall;
(2) >10% of samples for the Oregon-Washington Coastal stock; and (3)
>10% of scats of the Northern Inland Waters stock. PC = prey
composition.

Common name                  Scientific name            Total FO (%)

(1) SAMPLE OVERALL                                      (n = 13,088)
North Pacific Hake           Merluccius productus           35.20
Pacific Herring              Clupea pallasii                32.01
Shiner Perch                 Cymatogaster aggregate/        11.06

(2) SAMPLE OR-WA                                         (n = 3960)
Pacific Herring              Clupea pallasii                23.32
Pacific Staghorn Sculpin     Leptocottus armatus            19.70
Pacific Tomcod               Microgadus proximus            17.34
North Pacific Hake           Merluccius productus           14.20
Californian Anchovy          Engraulis mordax               12.55
Eulachon                     Thaleichthys pacificus         10.44
Shiner Perch                 Cymatogaster aggregata         10.36

(3) NORTHERN INLAND WATERS                               (n = 1792)
Pacific Herring              Clupea pallasii                43.76
Pacific Sand Lance           Ammodytes hexapterus           15.75
Shiner Perch                 Cymatogaster aggregata         13.79
Alaska Pollock               Theragra chalcogramma          13.70
Californian Anchovy          Engraulis mordax               10.35
Three-spined Stickleback     Gasterosteus aculeatus         10.06

Common name                  Total PC (%)

(1) SAMPLE OVERALL
North Pacific Hake              16.28
Pacific Herring                 14.80
Shiner Perch                     5.12

(2) SAMPLE OR-WA
Pacific Herring                  9.72
Pacific Staghorn Sculpin         8.21
Pacific Tomcod                   7.23
North Pacific Hake               5.92
Californian Anchovy              5.23
Eulachon                         4.36
Shiner Perch                     4.32

(3) NORTHERN INLAND WATERS
Pacific Herring                 16.83
Pacific Sand Lance               6.05
Shiner Perch                     5.30
Alaska Pollock                   5.27
Californian Anchovy              3.98
Three-spined Stickleback         3.87

TABLE 4. Top prey by frequency of occurrence >20% for 3 seasonal
groups.

Summer-fall     FO (%)   Winter-spring       FO (%)
(n = 10,026)             (n = 2164)

Gadiformes      54.26    Clupeiformes        56.62
Clupeiformes    51.30    Gadiformes          48.74
Salmoniformes   24.96    Perciformes         29.67
Perciformes     22.09    Pleuronectiformes   24.00
                         Scorpaeniformes     22.42

Summer-fall     All seasons         FO (%)
(n = 10,026)    (n = 898)

Gadiformes      Clupeiformes        52.10
Clupeiformes    Gadiformes          32.47
Salmoniformes   Pleuronectiformes   30.40
Perciformes     Perciformes         27.24
                Scorpaeniformes     24.80


SHEANNA STEINGASS

Department of Fisheries and Wildlife and Marine Mammal Institute, Oregon State University, 2030 SE Marine Science Drive, Newport, OR, USA; sheanna.steingass@oregonstate.edu

* Unpublished.

Caption: FIGURE 1. Locations represented by studies of Harbor Seal prey consumption by FO in the northern CCLME, by author and approximate location of sample collection. Duplicate markers have been removed for clarity.

Caption: FIGURE 3. Locations represented by studies of Harbor Seal prey consumption by FO in the Puget Sound, by author. Duplicate markers have been removed for clarity.
Caption: FIGURE 2. Total sample size representation by
season (winter-spring, summer-fall, or all seasons; n
= 13,088).

ALL SEASONS      7%
WINTER-SPRING   15%
SUMMER-FALL     77%

Note: Table made from pie chart.
COPYRIGHT 2017 Society for Northwestern Vertebrate Biology
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 2017 Gale, Cengage Learning. All rights reserved.

Article Details
Printer friendly Cite/link Email Feedback
Author:Steingass, Sheanna
Publication:Northwestern Naturalist: A Journal of Vertebrate Biology
Article Type:Report
Geographic Code:1USA
Date:Mar 22, 2017
Words:9041
Previous Article:Yellow-rumped warblers use two song categories: each male tends to use a unique song in each category in Southern Oregon.
Next Article:Histology reveals testicular oocytes and trematode cysts in the threatened Oregon spotted frog (Rana pretiosa).
Topics:

Terms of use | Privacy policy | Copyright © 2019 Farlex, Inc. | Feedback | For webmasters