The organisms living around energized submarine power cables, pipe, and natural sea floor in the inshore waters of Southern California.
It is likely that for the foreseeable future, offshore renewable energy technologies will focus on the generation of electricity from renewable resources (e.g., wind and wave). Specifically in U.S. waters, there has been substantial interest in wind energy off the East Coast of the United States (Petruny-Parker et al. 2015; BOEM 2014), both wind and wave energy off the Pacific Coast (Boehlert et al. 2013), and harnessing tidal energy in Puget Sound (Thomson et al. 2012). These technologies harness energy from an array of individual devices and, through power cables, send electricity to shore via cables. These cables will transmit either alternating current or direct current, and, if the cable uses alternating current, this current will generate both electric and magnetic fields around these cables.
Research has shown that cartilaginous and some bony fishes, as well as at least some invertebrates, are sensitive to electromagnetic fields (EMF) and that these fields can alter the behavior of these organisms (Kalmijn 1982; Formicki et al. 2004; Tanski et al. 2005; and summarized in Normandeu et al. 2011). However, worldwide, only a few studies have been conducted to document the effects of EMF on marine organisms in situ (DONG Energy and Vattenfall 2006; Ohman et al. 2007; Westerberg and Lagenfelt 2008) or in a semi-artificially enclosed mesocosm (Gill et al. 2012). These studies have yielded either equivocal, or at best subtle, evidence of marine organisms responding to artificially induced EMF in a natural or semi-natural environment.
Submarine transmission cables that power offshore oil platforms in the Pacific Region provide an opportunity to examine potential responses of marine organisms to offshore renewable energy development (Fig. 1). We note that these power cables are industry standard, the type that will be used for connecting devices (35 KV) within renewable energy installations.
Specific objectives of this study were to determine:
1) If differences exist among fish, invertebrate, and plant communities associated with an energized cable habitat and those communities around a nearby pipe and soft seafloor lacking an energized cable.
2) If electro-sensitive species that are regionally important, such as sharks and rays, respond (via either attraction or repulsion) to the EMFs of an in situ power transmission cable.
3) The potential effectiveness of the commonly proposed mitigation of cable burial.
Materials and Methods
Our surveys were conducted by scuba off the coast of Las Flores Canyon, southern California (34[degrees]27.6'N, 120[degrees]02.7' W). In this area there are 1) three 20.32 cm (8") diameter submarine power cables (variously energized and unenergized) providing power to three offshore oil platforms and 2) a 30.48 cm (12") diameter pipe running from the platforms to shore (Fig. 1). The furthest distance between the outermost cable and the pipe is about 40m.
Prior to beginning the study, we found that sections of cable were both exposed and buried by natural disturbances and that EMF levels were lower on the sandy substrate directly over the buried cable than on the exposed cable. Thus to study the effect of the maximum EMF possible, we determined the survey would be conducted along unburied sections of the cable. Divers observed cables and pipeline for exposed continuous 30-m long sections, a standard transect length that we and other research groups have used for fish surveys in the region. We were able to find sufficient lengths of exposed energized cables (known as cables A and B) where fixed 30-m long transects could be set at two bottom depths. An unenergized cable (known as cable CI) was mostly buried, and we did not find any exposed 30-m lengths. Thus, for these surveys, we used the nearby exposed pipe as a surrogate for an unenergized cable. Divers surveyed fishes, invertebrates, and macrophytes along three habitats: an energized submarine power cable, a pipe, and a sandy, natural control area to the west of both cables and pipe (Fig. 2).
The experimental design was comprised of six fixed 30 m-long transects (treatments) of which one was installed in each of three habitats (along a cable, the pipe, and over sandy bottom) and in each of two depths (shallow. 10-11 m; and slightly deeper waters, 13-14 m depth). The end of the shallow transects and beginnings of the deep ones were separated by about 120 m. The beginning and ending of each transect in each habitat was marked by sand anchors as was each 5 m segment along each transect. Transects were 2 m wide, centered on the pipe or cable or an imaginary line between sand anchors that delineated the sandy control transect. Surveys of fishes, macroinvertebrates, and macrophytes were conducted every 2-4 weeks along the six transects during daylight hours by two divers.
At the beginning of the study we measured the EMF emitted by the power cables in our study area and found that two cables, A and B, were energized. We began our cable surveys on energized cable B. However, on 15 May 2013, we detected that cable B had become unenergized and we switched our surveys to energized cable A for the duration of the study. Importantly, both cables A and B had been energized for at least several years before cable B was switched off (D. Gilbert, pers. comm. to M. L.). The magnitude of EMF was measured at the beginning of each survey. A diver recorded readings from a detector placed directly against the cable, pipe, and sand. We used the Kruskal-Wallis one-way ANOVA on ranks to test for a difference in EMF field strength among habitats (Cable B, Cable A, Pipe, and natural habitat). The Wilcoxon test was used for nonparametric comparisons to identify where the EMF differed. The first diver surveyed all fishes encountered within 2 m above the substrate. Fish were identified to species, counted, and sized by eye to the nearest centimeter. A second diver followed and recorded the number of macrophytes in the 2 m swath centered over the cable and pipe or on the sand. The quantification of macrophytes was used to determine if these structure-forming organisms differentially modified the habitats. The second diver also recorded macroinvertebrates (i.e., cnidarians. mollusca, crustaceans, and echinoderms) encountered within the same 2-m-wide sampling area. Only individual invertebrates of at least 10 cm in any dimension were recorded.
We used the Kolmogorov Smirnov Two-Sample test to evaluate whether the size frequency distribution of all fishes differed between the cable, pipe, and natural habitats. Mean lengths among habitats were compared using Welch's test. The fish length observations from both cables A and B were combined for this analysis. We employed the permutational analysis of variance routine in PERMANOVA + for PRIMER (Anderson et al. 2008) to test the response (counts per transect) of the fish, invertebrate, and macrophyte communities, separately, to one or more of the factors: habitat (cable, pipe, natural), depth (shallow, deep), and time (survey). The dataset was divided into two periods; the first when cable B was surveyed and the second when cable A was surveyed. This was a reasonable approach given that the two cable environments were seen to be quite different in terms of the structure-forming macrophyte community that could possibly affect fish and mobile macroinvertebrate abundance. By analyzing data separately from each cable, we were able to determine whether, if a species was more abundant at either a cable or pipe, this pattern occurred at both energized cables (implying that EMF may have been responsible) or only at one of the cables (implying that some other environmental factor was responsible). The experimental design was a balanced, repeated measures 3-way analysis with fixed factors for each period of surveys. During each survey date, we sampled six different treatments (i.e., transects) without replication. The terms of the model were habitat, depth, time, habitat x depth, habitat x time, and depth x time. If the effect of habitat on the abundance of a species was significant (p<0.05), then posthoc PERMANOVA permutational t-tests were run for independent pairwise comparisons of abundance between cable, pipe, and natural habitat. P-values in the PERMANOVA routines were calculated using 9999 permutations that generated the test statistic distribution under a true null hypothesis based on the resemblance between the samples. The observations of fish and invertebrate counts per transect were log (x+1) transformed and the macrophyte dataset of counts per transect was square-root transformed before calculating the Bray-Curtis similarity coefficients that quantified the resemblance between multivariate transect samples. We used the PERMDISP routine in PRIMER to determine that either log(X+l) or square root transformations of the abundance data (count per transect) reduced the heterogeneity of dispersion of multivariate samples among the different experimental treatments. Similarly, we used the permutational analysis of variance routine to test the response (number per transect) of abundant individual species of fishes, invertebrates, and macrophytes to the same factors. The individual species data were transformed using either log(x+l) or square-root of x. The test statistic for individual species is based on a Euclidean distance matrix between samples (Anderson et al. 2008).
We used multidimensional scaling (M DS) ordination in PRIMER v6 (Clarke and Gorley, 2006) to visualize assemblage groupings of transect samples by habitat and depth. As a complement to the PERMANOVA analysis, we used a two-way crossed analysis of similarity (ANOSIM) in PRIMER to evaluate the degree of overlap in species composition across habitat and depth.
ANOSIM operates on the resemblance matrix to test the null hypothesis that there are no assemblage differences between pipe, cable, and natural habitats (factor A), allowing that there may be shallower/deeper differences (factor B), The ANOSIM sample test statistic, R, ranges from 0 (no difference between groups) to 1 (all dissimilarities between the groups are larger than any dissimilarities among samples with either group). A statistically significant (p<0.05) but negligibly small R-value close to 0 indicates that species composition differ between habitats, but strongly overlap.
From 1 February 2012 to 26 February 2014, fishes and macrophyte surveys were conducted from the beginning to end of the study. Invertebrate surveys were conducted beginning on 22 June 2012 and continued until the end of the study. Surveys were conducted on a total of 38 days (Table 1). We note that the natural habitat was sand and eelgrass. Over the course of the study, average EMF levels at the two cables (A and B) were statistically similar (Cable A = 73.0[micro]T, Cable B = 91.4[micro]T) and were statistically higher at the two cables compared to the pipe (average = 0.5[micro]T) or sand (0[micro]T) (Fig. 3, Table 2). We note that previous studies have demonstrated that EMF levels reach background levels about one meter from this cable (Love et al. 2015, 2016).
We found that the fish community varied among the cables, pipe, and natural habitat; however, there was significant interaction between the effects of habitat and depth on assemblage structure (Table 3). Furthermore, the 3-dimensional MDS plots of the assemblages from transect samples demonstrates there is substantial overlap of the habitat groupings during the periods when Cable A (global R=0.043, p=0.007; Fig. 4) and Cable B were surveyed (global R=0.253, p=0.0001; Fig. 5). Depth-related differences appeared to be somewhat more pronounced when Cable A is compared to the pipe and natural habitat rather than in similar comparisons with Cable B (Fig. 4 and Fig 5, respectively).
We conducted a total of 38 days of fish surveys during three years. Over all habitats, 4465 individuals representing at least 44 species (summed from Tables 4, 5) were observed. Dominant species included adults of benthic-oriented, schooling taxa (i.e., Oxyjulis californica, Brachyistiusfremitus, Phanerodon furcatus, and Cymatogaster aggregate/), young-of-the-year (YOY) Sebastes that had newly settled out of the plankton (particularly Sebastes chrysomelas, S. carnatus, and S. atrovirens), and relatively solitary substrate-oriented species (i.e., Citharichthys spp.). Oxyjulis californica, Citharichthys spp., Phanerodon furcatus, YOY Sebastes, and B. fremitus were the most abundant taxa. Cables: At least 35 species and 1,661 individuals were observed over the energized cables. Oxyjulis californica, Citharichthys spp., B. frenata, P. furcatus, and YOY Sebastes were most abundant (Tables 4, 5). Pipe: The number of taxa (37) and individuals (1,712) were similar to those observed on the cables. Oxyjulis californica, YOY Sebastes, Sebastes miniatus YOY, Damalichthys vacca, Embiotoca jacksoni, and Citharichthys spp. were the most abundant taxa on the pipe (Tables 4, 5). Natural Habitat: Fewest species (25) and individuals (1,092) were observed over the natural habitat. Cymatogaster aggregata, Citharichthys spp., O. californica, YOY Sebastes jordani, P. furcatus, and Aulorhynchus flavidus were the most commonly observed species (Tables 4, 5).
Fish communities among all habitats were composed primarily of small-sized fishes with most being less than 20 cm long. The mean lengths of fishes (cables = 11.8 cm, pipe =11.4 cm. natural habitat = 9.7 cm) varied significantly among the three habitats (Welch's Test, F = 43.7, df = 2, p < 0.0001) as did the size distributions (Kolmogorov Smirnov Two-Sample Test: cables versus pipe, N = 3,484 K.S 0.053, p = <0.0001; cables versus natural habitat, N = 2,832 K.S 0.147, p = <0.0001; pipe versus natural habitat, N = 2,890 KS 0.117, p = <0.0001).
While the overall fish communities were similar among the three habitats, there were some fish species that were statistically more abundant over parts of either the cables or pipe (Table 3, Fig. 6). As examples, O. californica, Citharichthys spp., and E. jacksoni were all more abundant over Cable B than over the pipe (Table 3, Fig. 6). Similarly, B. fremitus, Sebastes paucispinis YOY, and Heterostichus rostratus were more abundant over Cable A compared to the pipe. However, with the exception of Citharichthys spp., none of these species were consistently more abundant at either the cablcs or the pipe or over both depths. Rather, in virtually all of these instances these differences were cither 1) limited to one of the two cables or 2) were not consistent between depths (Fig. 6). As an example, while O. californica was statistically more abundant at Cable B than at the pipe, it was less abundant at Cable A compared to the pipe. Similarly, Hypsunts caryi were more abundant on the inshore parts of the pipe compared to Cable A, but not on the offshore parts.
As with the fish community, the invertebrate assemblages varied among the cables, pipe, and natural habitat with significant interaction between the effects of habitat and depth on assemblage structure (Table 6). The three-dimensional MDS plots of the assemblages from shallow and deep transect samples demonstrates substantial overlap of the habitat groupings during the periods when both cable B (global R=0.085, p=0.002; Fig. 7) and cable A were surveyed (global R=0.227, p=0.000l; Fig. 8). We conducted a total of 30 days of invertebrate surveys during three years. A total of 802 individuals were observed, comprising at least 19 species (Tables 7, 8). Patiria miniata, several species of Pisaster sea stars, Aplysia californica, Astropecten armatus, and Kelletia kelletii were observed most often. By group, sea stars were the most abundant, comprising 56.8% of all invertebrates observed. Cables-. We recorded 157 individuals of at least 15 species at the cable sites. P. miniata, Pisaster sea stars, and A. californica were most abundant (Tables 7, 8). Pipe: A total of 422 individual invertebrates, more than any other site, were observed at the pipe. However, 100 of these individuals were comprised of a one-time recorded aggregation of Strongylocentrotuspurpuratus. Like the cables, we recorded 15 species along the pipe (Tables 7, 8). Natural Habitat'. Patiria miniata and K. kelletii predominated in the natural habitat, where we recorded 223 individuals, of 13 species (Tables 7, 8). Again, consistent with what we observed for fish species, in comparing cables with the pipe, only one invertebrate species was consistently more abundant in either habitat: Pisaster spp. were more abundant over the pipe (Table 8, Fig. 9). Several other species, such as P. miniata, Parastichopus spp., A. californica, and Parastichopus spp. were not consistently more abundant on either cables or pipe.
In contrast to the fish and invertebrate communities, the macrophyte assemblages were strikingly distinct from one another by habitat and depth. The interaction between these two effects on assemblage structure was significant (Table 9). The 3-dimensional MDS plots of the assemblages from shallow and deep transect samples demonstrates no overlap of the habitat groupings during the periods when Cable B (global R=0.998 p=0.0001; Fig. 10) and Cable A were surveyed (global R=0.993, p=0.0001; Fig. 11).
We conducted a total of 38 days of surveys during three years. A total of 76358 individual macrophytes (many likely observed repeatedly on sequential survey days) were tallied, comprising at least five species (Table 10). Overall, Zostera marina was most abundant (and found only on the natural habitat), followed by Pteiygophora californica, Cystoseira spp., Macrocystispyrifera, and Laminaria spp. Cables: Overall, Pteiygophora californica dominated the cable community, although Cystoseira spp. and Laminaria spp. were not uncommon (Table 10). However, note that P. californica was very abundant on Cable B (particularly shallower), but much less so on Cable A (Table 10). Zostera marina grew on the sand near the cable. Macrocystis pyrifera grew very sparsely on the shallower Cable B habitat, was more common on the shallower part of Cable A, and was essentially absent from the deeper cables (Fig. 12). Pipe: Cystoseira spp. was the most common macrophyte on the pipe (Table 10). Cystoseira spp. was about twice as abundant shallower than deeper while Laminaria spp. was almost absent from the shallower site and nearly as abundant as Cystoseira spp. deeper (Fig. 12). Relatively few P. californica were observed on the pipe and both M. pyrifera and Z marina were almost absent. Natural Habitat: Zostera marina was the only macrophyte growing on the sandy sea floor of the natural habitat (Table 10). It was dense at both the shallower and deeper sites (Fig. 12). As noted above, the macrophyte communities in the three habitats differed among each other and along the inshore and offshore transects. This was reflected in the distribution of all macrophyte species when comparing cable and pipe habitats (Table 10). Unlike with virtually all of the fish species and all of the invertebrate species, the differences in abundances were consistent between both cables and the pipe and at both depths (Fig. 12).
Discussion and Conclusions
We began this study with the understanding that if a species is attracted to an EMF we would expect to find that species in disproportionately larger numbers or densities around the energized cables compared to the pipe or natural habitat. Similarly, if a taxa is repelled by that EMF we would expect that species to be present less often or in lower densities at the cables. However, the presence or absence of an EMF is not the only habitat parameter influencing how an organism chooses its habitat. We acknowledge that in this study the cables and pipe differed not only in the production of an EMF but to some extent in the morphology of these habitats. In particular, the pipe was a slightly more complex structure. First, the pipe's diameter (30.48 cm) was somewhat greater than that of the two cables (20.32 cm), and while the cable was sometimes partially buried, the pipe was not. Thus for both reasons the pipe tended to present a somewhat higher profile. In addition, perhaps the greatest structural difference between the cables and pipe was the very high density, particularly on the shallower pipe, of Cystoceira sp., a brown alga that was essentially absent from the shallower cable. This alga forms a dense cover near the bottom and small fishes, particularly YOY Sebastes, will preferentially inhabit this complex substratum.
Algae also grew on the cable, particularly Macrocystis pyrifera on the shallower area of Cable A, and Laminaria sp. on the deeper portion of both cables. However, M. pyrifera does not form luxuriant bottom structures and the Laminaria stands, while present, did not present as dense a cover as the Cystoceira on the pipe. The sandy natural habitat was the least complex of all three; its two-dimensional aspect was only broken up by stands of Z. marina. At the start of the study Z. marina was only sporadically found and became more abundant over time.
Structural variability aside, the results of our study demonstrated that the fish and invertebrate assemblages of the three habitats were similar. Although a few species statistically varied in abundance between the cables and pipe, in no instance was a fish or invertebrate species extremely abundant at one of these two habitats and extremely rare or absent from the other. And although fishes were statistically larger at the pipe than at the cable or natural habitat, we argue that this difference (of less than one-half centimeter between pipe and cable and two centimeters between pipe and natural habitat) is not biologically meaningful.
Results of this study found no evidence that any species of fish or invertebrate was either preferentially attracted to, or repelled by, the EMF emitted by the cables. Any observed differences in the fish or invertebrate densities between cables, pipe, and natural habitat taxa are most likely due to the differences in the physical characteristics of these habitats. For example, the higher densities of YOY Sebastes and E. jacksoni at the pipe are most likely due to greater densities of understory algae, specifically Cvstoseira spp. In addition, the lower-relief cables, which were closer to the sandy sea floor, were a better habitat for soft-bottom dwelling sanddabs. Contrary to the fish and invertebrate assemblages, the plant communities on cables, pipe, and natural habitat were clearly different from one another. However, if cable EMF were responsible for these differences, we would expect to see similarities in plant communities between energized cables A and B and this was not the case. Rather, it appears that plant communities were driven by site depth (particularly among the algae) and habitat type (i.e., eelgrass).
We note that this study was not designed to directly determine the behavior of fishes and invertebrates when these organisms encounter an energized cable during, for instance, migrations. Rather, we observed the integration over time of myriads of such behaviors by many organisms. Understanding how individuals within a taxon relate to energized cables would have to involve either tracking (Westerberg and Lagenfelt 2008) or caging experiments (Love et al. 2015) or hybrids of the two (Gill et al. 2009).
In southern California, most along-shore migrations (as distinct from less synchronized movements) are conducted by such pelagic species as Prionace glauca and Sardinops sagax. The more substrate-associated shallower species (exemplified by the taxa that dominated our survey) tend to be either resident (i.e., Cephaloscyllium ventriosum, E. jacksoni), make seasonal shallower-deeper movements (H. caryi), or locally disperse as they mature (YOY Sebastes spp., C. aggregata). Given that the EMF emitted from the study cables is undetectable beginning at a distance of about one meter (Love et al. 2015, Love unpubl. data) it would be unlikely that pelagic and midwater species are affected by this field. In fact, the limited range of the EMF implies that only the movements of those species that live close to the bottom would be potentially impacted.
In our study area, some of the bottom-dwelling or bottom-oriented species most likely to respond to energized cables are the elasmobranchs: the sharks, skates, and rays. It is probable that all of these fishes can detect an EMF and this ability appears to be used for a number of behaviors including migration and food detection (Kalmijn 1971, Tricas 1982, Klimley et al. 2005). Moreover, while the actual sensitivity to an EMF is known for only a few elasmobranch species, we note that at least two Atlantic species, Carcharhinus plumbeus and Sphyrna lexvini, are able to detect an EMF in the 25-100pT range (Meyer et al. 2005); this is within the range generated by the current surveys' energized cables.
The shallower habitats of southern California, and specifically this study site, harbor a rich diversity of elasmobranchs (Love 2011). These include both mobile taxa (e.g., Triakis semifasciata and Mustelus spp.) and more sedentary species (Rhinobatosproductus, Platyrhinoidis triseriata, and Squatina californica). Given this diversity, it is interesting to note that over the course of this study we observed only two elasmobranch individuals, C. ventriosum near the pipe and Urobatis halleri near Cable B. It might be argued that the chances of seeing individuals of the more motile species would be small on any given day; although these chances would likely be increased if the animals were attracted to the cables. However, if the more sedentary species were similarly attracted, one might expect to have encountered them. And again, the absence of these animals from the cable is likely not because the EMF generated is below their sensory threshold. Rather, the data strongly imply that of the electro-sensitive species in the study area, at least the elasmobranchs are not attracted to the energized cables.
Our findings are particularly important because, worldwide, the small number of field or semi-field studies that have been conducted on how fishes respond to energized power cables have found either little or no response (Westerberg and Lagenfelt 2008, DONG Energy and Vattenfall A/S 2006, Love et al. 2015, present study) or, arguably, an equivocal one (Gill et al. 2009). One possible explanation is that marine organisms respond to human-made EMF differently from those produced in nature. Recent studies demonstrate that human-made EMF is inherently different from naturally produced EMF, with naturally produced EMF being polarized and consequently more biologically active (Panagopoulos et al. 2015). Thus, it is possible that electro-sensitive organisms are able to differentiate between the two types and therefore respond differently to each of these stimuli.
Regarding the specific objectives of this study:
1) Differences exist among fish and invertebrate communities associated with energized and unenergized cable habitat and those communities in soft seafloor habitats lacking cables.
We did not find any biologically significant differences among fish and invertebrate communities between energized cables, pipe, and natural habitat. In particular, only three species of fish showed statistically significant, but slight, differences in densities between the cables and pipe. Plant communities did differ among habitats and within habitats between depths. These differences were almost certainly structure and depth, rather than EMF, related.
2) Electro-sensitive species that are regionally important, such as sharks and rays, respond (via either attraction or repulsion) to the EMEs of an in situ power transmission cable.
We observed two elasmobranch individuals, C. ventriosum near the pipe and Urobatis halleri near one of the two energized cables, during the course of this study. Thus, it would appear that the EMFs generated by energized cables are either unimportant to these organisms or that at least other environmental factors take precedence.
3) The potential effectiveness of the commonly proposed mitigation of cable burial.
Given the rapidity with which the EMF produced by the energized cables diminishes and the lack of response to that EMF by the shallower fish and invertebrates, cable burial would not appear necessary strictly for biological reasons. In this and similar cases, cable burial, at sufficient depth, would be an adequate tool to prevent EMF emissions from being present at the seafloor.
We thank Donald Macaskill, Jorge Gross, Frank Hurd, Jacob Eurich, Donna Schroeder, and Christopher Teague for their field assistance. This work was funded by the Bureau of Ocean Energy Management (BOEM), BOEM Cooperative Agreement No. Ml 1AC00008.
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Milton S. Love, (1) * Mary M. Nishimoto, (1) Scott Clark, (1) Merit McCrea, (1) and Ann Scarborough Bull (2)
(1) Marine Science Institute, University of California, Santa Barbara, CA 93106
(2) Bureau of Offshore Energy Management, 770 Paseo Camarillo, Camarillo, CA 93010
* Corresponding author: email@example.com
Caption: Fig. 1. Location of the energized and unenergized submarine power cables and pipe in the study area.
Caption: Fig. 2. Schematic illustration of cables, pipe, and natural habitat surveyed by scuba, 1 February 2012-26 February 2014. Cables A and B were energized and were used in this study. The nearshore section of Cable C has been removed. Cable [C.sup.1] was unenergized and was not used in this study as it was mostly buried in the sea floor. Distance between cables, pipe, and natural habitat not drawn to scale.
Caption: Fig. 3. Electromagnetic field levels measured on cables, pipe, and natural habitat surveyed from 1 February 2012-26 February 2014. Vertical bars represent standard errors.
Caption: Fig. 4. A 3-d multiple dimensional scaling model comparing the fish assemblages from shallower and deepertransects in Cable B, pipe, and natural habitat.
Caption: Fig. 5. A 3-d multiple dimensional scaling model comparing the fish assemblages from shallower and deeper transects in Cable A, pipe, and natural habitat.
Caption: Fig. 6. Mean fish species densities found at the shallower and deeper sites at the three habitats. Data is divided into two periods when 1) Cable B was surveyed and 2) when Cable A was surveyed. KGB = young-of-the-year Sebastes atrovirens, S. carnatus, S. chrvsomelas, and 5. caurinus.
Caption: Fig. 7. A 3-d multiple dimensional sealing model comparing the invertebrate assemblages from shallower and deeper transects in Cable B, pipe, and natural habitat.
Caption: Fig. 8. A 3-d multiple dimensional scaling model comparing the invertebrate assemblages from shallower and deeper transects in Cable A, pipe, and natural habitat.
Caption: Fig. 9. Mean invertebrate species densities found at the shallower and deeper sites at the three habitats. Data is divided into two periods when 1) Cable B was surveyed and 2) when Cable A was surveyed.
Caption: Fig. 10. A 2-d multiple dimensional scaling model comparing the macrophyte assemblages from shallower and deeper transects in Cable B, pipe, and natural habitat.
Caption: Fig. 11. A 2-d multiple dimensional scaling model comparing the macrophyte assemblages from shallower and deeper transects in Cable A, pipe, and natural habitat.
Caption: Fig. 12. Mean macrophyte species densities found at the shallower and deeper sites at the three habitats. Data is divided into two periods when 1) Cable B was surveyed and 2) when Cable A was surveyed.
Table 1. All dates of surveys on energized cables, pipe, and natural habitat. Fishes and plants were surveyed on all dates; invertebrates were surveyed from 22 June 2012 to 26 February 2014. Surveys were conducted on energized Cable B from 1 February 2012 to 15 May 2013 and on energized Cable A from 14 June 2013 to 26 February 2014. 2012 1 Feb. 22 Feb. 8 Mar. 27 Mar 12 Apr. 13 July 25 July 10 Aug. 22 Aug 11 Sept. 2013 8 Jan. 5 Feb. 28 Feb. 12 March 3 Apr. 9 July 16 Aug. 30 Aug. 13 Sept. 30 Sept. 31 Dec. 2014 15 Jan. 12 Feb. 26 Feb. 2012 1 Feb. 24 Apr. 9 May 8 June 22 June 13 July 2 Nov. 7 Dec. 2013 8 Jan. 24 Apr. 3 May 15 May 14 June 9 July 18 Oct. 8 Nov. 20 Nov. 6 Dec. 31 Dec. 2014 15 Jan. Table 2. Wilcoxon test values comparing EMF field strengths of two energized cables, pipe, and natural habitat, 2012-2014. NH = natural habitat. Site Site Mean Standard Z p-value Difference Error Cable B Cable A 5.95 4.15 1.43 0.15 NH Cable A -32.46 4.40 -7.38 <.0001 Pipe Cable A -34.46 5.30 -6.50 <.0001 Pipe Cable B -36.39 5.30 -6.87 <.0001 NH Cable B -36.97 4.67 -7.92 <.0001 NH Pipe -43.74 5.34 -8.18 <.0001 Table 3. P-values from the repeated measures PERMANOVA testing the effects of habitat (HA), depth (IN), and sampling date (DA) on fish community structure and density of individual taxa and from PERMANOVA pairwise tests for differences between habitats for the periods when Cables B and A were surveyed. YOY = young-of-the-year. Species selected were those that comprised at least 1% of all fishes observed. Statistically significant results are underlined. Cable B HA IN DA Fish community 0.0001 0.0287 0.0001 Taxon: Oxvjulis californica 0.0347 0.9836 0.0001 Citharichthys spp. 0.0007 0.4798 0.0007 Phanerodon furcatus 0.1716 0.1071 0.0313 Cvmatogaster aggregata 0.1005 0.6411 0.0001 KGB YOY (1) 0.0038 0.0341 0.0006 Brachvistius fremitus 0.3762 0.1600 0.4938 Sebastes miniatus YOY 0.0916 0.0001 0.0001 Embiotoca jacksoni 0.0033 0.0916 0.0162 Aulorhynchus flavidus 0.4649 0.3638 0.4685 Hvpsurus carvi 0.4824 0.0381 0.0037 Damalichthvs vacca 0.0573 0.1179 0.4520 Sebastes caurinus 0.4054 0.3437 0.3529 Sebastes paitcispinis YOY 0.1283 0.4334 0.0667 Sebastes 0.3805 0.2238 0.0121 serranoidestSebastes flavidus YOY Heterostiehus rostratus 0.0318 0.2473 0.0162 Cable B HAxIN HAxDA INxDA Fish community 0.0127 0.5245 0.1356 Taxon: Oxvjulis californica 0.0144 0.8534 0.7389 Citharichthys spp. 0.0325 0.8485 0.0311 Phanerodon furcatus 0.1453 0.7047 0.9496 Cvmatogaster aggregata 0.8181 0.0014 0.9112 KGB YOY (1) 0.2227 0.1552 0.0718 Brachvistius fremitus 0.4066 0.5033 0.5837 Sebastes miniatus YOY 0.0121 0.1177 0.0001 Embiotoca jacksoni 0.8015 0.0412 0.3053 Aulorhynchus flavidus 0.1924 0.4316 0.4712 Hvpsurus carvi 0.1316 0.7651 0.1409 Damalichthvs vacca 0.0224 0.4984 0.4779 Sebastes caurinus 0.4371 0.511 1 0.4941 Sebastes paitcispinis YOY 0.6773 0.9587 0.1426 Sebastes 0.9045 0.8630 0.0053 serranoidestSebastes flavidus YOY Heterostiehus rostratus 0.0148 0.6152 0.9351 Cable B Cable, Cable, Pipe, pipe natural natural Fish community 0.0016 0.0051 0.0002 Taxon: Oxvjulis californica 0.0470 0.0546 0.9695 Citharichthys spp. 0.0001 0.1 107 0.0494 Phanerodon furcatus Cvmatogaster aggregata KGB YOY (1) 0.5834 0.0008 0.0092 Brachvistius fremitus Sebastes miniatus YOY Embiotoca jacksoni 0.0473 0.0661 0.0077 Aulorhynchus flavidus Hvpsurus carvi Damalichthvs vacca Sebastes caurinus Sebastes paitcispinis YOY Sebastes serranoidestSebastes flavidus YOY Heterostiehus rostratus 0.5088 0.0085 0.0092 Cable B HA IN DA Fish community 0.0001 0.0001 0.0001 Taxon: Oxvjulis californica 0.0027 0.0161 0.0001 Citharichthys spp. 0.0022 0.0001 0.1479 Phanerodon furcatus 0.0199 0.1778 0.0126 Shiner perch 0.0406 0.5422 0.0291 KGB YOY (1) 0.0001 0.0067 0.0001 Brachyistius frenatus 0.0166 0.0096 0.2912 Sebastes miniatus YOY 0.3610 0.0793 0.0660 Embiotoca jacksoni 0.0001 0.0001 0.0062 Aulorhynchus flavidus 0.4554 0.7378 0.3142 Hypsurus caiyi 0.0004 0.0006 0.0314 Damalichthys vacca 0.0691 0.0012 0.4786 Sebastes caurinus 0.0004 0.2144 0.0008 Sebastes paucispinis YOY 0.0438 0.8801 0.8572 Sebastes 0.4668 0.9484 0.1391 serranoides!Sebastes flavidus YOY Heterostichus rostratus 0.0050 0.0306 0.1265 Cable B HAxIN HAxDA INxDA Fish community 0.0002 0.0085 0.0001 Taxon: Oxvjulis californica 0.0356 0.5450 0.0002 Citharichthys spp. 0.1831 0.5405 0.3673 Phanerodon furcatus 0.2533 0.1704 0.0041 Shiner perch 0.6874 0.0094 0.4952 KGB YOY (1) 0.0466 0.0028 0.1993 Brachyistius frenatus 0.0111 0.5226 0.2729 Sebastes miniatus YOY 0.0805 0.1797 0.0528 Embiotoca jacksoni 0.0002 0.4926 0.0375 Aulorhynchus flavidus 0.8891 0.9822 0.8205 Hypsurus caiyi 0.0093 0.8955 0.2189 Damalichthys vacca 0.3506 0.4163 0.2530 Sebastes caurinus 0.3915 0.0298 0.3777 Sebastes paucispinis YOY 0.7147 0.7701 0.5658 Sebastes 0.3712 0.9601 0.7776 serranoides!Sebastes flavidus YOY Heterostichus rostratus 0.0145 0.1581 0.0474 Cable B Cable, Cable, Pipe, pipe natural natural Fish community 0.0004 0.0003 0.0001 Taxon: Oxvjulis californica 0.0210 0.0949 0.0105 Citharichthys spp. 0.0068 0.8271 0.0025 Phanerodon furcatus 0.0516 0.0108 0.2880 Shiner perch 0.3513 0.0165 0.1574 KGB YOY (1) 0.0001 0.0002 0.0001 Brachyistius frenatus 0.0409 0.0344 0.3601 Sebastes miniatus YOY Embiotoca jacksoni 0.1134 0.0003 0.0001 Aulorhynchus flavidus Hypsurus caiyi 0.0376 0.0429 0.0001 Damalichthys vacca Sebastes caurinus 0.1484 0.0003 0.0020 Sebastes paucispinis YOY 0.0480 0.1252 0.3454 Sebastes serranoides!Sebastes flavidus YOY Heterostichus rostratus 0.031 1 0.0070 0.2236 (1) Sebastes atrovirens, S. caurinus, S. carnatus, S. chrysomelas Table 4. Total count across all habitats and mean (SE) number of fishes per transect in each habitat during period when Cable B was surveyed, 1 February 2012-15 May 2013. Two transects, shallow and deep, were surveyed in each habitat on 23 sampling dates. Number of transect surveys in each habitat, n = 46. YOY = young-of-the-year. All Cable B habitats Scientific name Count Mean (SE) Oxyjulis californica 460 5.35 (1.75) Citharichthys spp. 496 5.48 (1.19) Phanerodon furcatus 111 0.78 (0.48) Cymatogaster aggregata 278 1.13 (0.69) Sebastes atrovirens, S. caurinus, 180 1.72 (0.58) S. carnatus, or 5. chrysomelas YOY Brachyistius fremitus 75 0.39 (0.15) Sebastes miniatus YOY 228 1.13 (0.57) Sebastes jordani YOY 190 0.43 (0.43) Embiotocajacksoni 78 0.39 (0.13) Aulorhynchus flavidus 158 0.72 (0.67) Hypsurus carvi 26 0.15 (0.07) Damalichthys vacca 119 0.02 (0.02) Sebastes caurinus 52 0.74 (0.41) Sebastes paucispinis 81 0.28 (0.20) Sebastes serranoides or S. 40 0.13 (0.08) flavidus YOY Heterostichus rostratus 23 0.30 (0.15) Sebastes semicinctus 29 0.22 (0.18) Synodus lucioceps 1 0.00 (0.00) Oxylebius pictus 12 0.09 (0.04) Sebastes mystinus 1 0.00 (0.00) Sebastes auriculatus 17 0.00 (0.00) Scorpaenichthys mannoratus 7 0.07 (0.04) Hexagrammos decagrammus 2 0.00 (0.00) Pleuronichthys coenosus 6 0.04 (0.03) Gibbonsia spp. 2 0.02 (0.02) Sebastes dalli 5 0.04 (0.03) Paralabrax clathratus 1 0.02 (0.02) Unidentified Cottidae 3 0.00 (0.00) Leiocottus hirundo 4 0.00 (0.00) Neoclinus blanchardi 1 0.02 (0.02) Ophiodon elongatus 5 0.04 (0.03) Paralichthys californicus 1 0.00 (0.00) Sebastes atrovirens 3 0.02 (0.02) Unidentified fishes 3 0.07 (0.05) Gibbonsia spp. 2 0.00 (0.00) Sebastes carnatus 1 0.02 (0.02) Paralabrax nebulifer 1 0.02 (0.02) Pleuronichthys decurrens 1 0.00 (0.00) Porichthvs spp. 1 0.00 (0.00) Rathbunella spp. 1 0.00 (0.00) Sebastes rastrelliger 1 0.00 (0.00) Urobatis halleri 1 0.02 (0.02) All fishes 2707 19.93 (3.91) Pipe Scientific name Mean (SE) Oxyjulis californica 2.78 (1.63) Citharichthys spp. 1.87 (0.48) Phanerodon furcatus 0.20 (0.09) Cymatogaster aggregata 0.09 (0.06) Sebastes atrovirens, S. caurinus, 2.11 (0.83) S. carnatus, or 5. chrysomelas YOY Brachyistius fremitus 1.22 (1.02) Sebastes miniatus YOY 3.30 (1.85) Sebastes jordani YOY 1.09 (1.09) Embiotocajacksoni 1.20 (0.46) Aulorhynchus flavidus 0.41 (0.18) Hypsurus carvi 0.28 (0.12) Damalichthys vacca 2.54 (1.94) Sebastes caurinus 0.33 (0.14) Sebastes paucispinis 1.46 (0.88) Sebastes serranoides or S. 0.67 (0.57) flavidus YOY Heterostichus rostratus 0.20 (0.11) Sebastes semicinctus 0.41 (0.39) Synodus lucioceps 0.00 (0.00) Oxylebius pictus 0.17 (0.06) Sebastes mystinus 0.02 (0.02) Sebastes auriculatus 0.37 (0.35) Scorpaenichthys mannoratus 0.09 (0.04) Hexagrammos decagrammus 0.04 (0.03) Pleuronichthys coenosus 0.02 (0.02) Gibbonsia spp. 0.02 (0.02) Sebastes dalli 0.07 (0.07) Paralabrax clathratus 0.00 (0.00) Unidentified Cottidae 0.07 (0.04) Leiocottus hirundo 0.07 (0.05) Neoclinus blanchardi 0.00 (0.00) Ophiodon elongatus 0.00 (0.00) Paralichthys californicus 0.00 (0.00) Sebastes atrovirens 0.04 (0.03) Unidentified fishes 0.00 (0.00) Gibbonsia spp. 0.04 (0.03) Sebastes carnatus 0.00 (0.00) Paralabrax nebulifer 0.00 (0.00) Pleuronichthys decurrens 0.00 (0.00) Porichthvs spp. 0.02 (0.02) Rathbunella spp. 0.02 (0.02) Sebastes rastrelliger 0.02 (0.02) Urobatis halleri 0.00 (0.00) All fishes 22.24 (5.56) Natural Scientific name Mean (SE) Oxyjulis californica 1.87 (0.95) Citharichthys spp. 3.43 (0.69) Phanerodon furcatus 1.43 (0.83) Cymatogaster aggregata 4.83 (4.35) Sebastes atrovirens, S. caurinus, 0.09 (0.04) S. carnatus, or 5. chrysomelas YOY Brachyistius fremitus 0.02 (0.02) Sebastes miniatus YOY 0.52 (0.30) Sebastes jordani YOY 2.61 (2.61) Embiotocajacksoni 0.11 (0.09) Aulorhynchus flavidus 2.30 (1.82) Hypsurus carvi 0.13 (0.07) Damalichthys vacca 0.02 (0.02) Sebastes caurinus 0.07 (0.04) Sebastes paucispinis 0.02 (0.02) Sebastes serranoides or S. 0.07 (0.04) flavidus YOY Heterostichus rostratus 0.00 (0.00) Sebastes semicinctus 0.00 (0.00) Synodus lucioceps 0.02 (0.02) Oxylebius pictus 0.00 (0.00) Sebastes mystinus 0.00 (0.00) Sebastes auriculatus 0.00 (0.00) Scorpaenichthys mannoratus 0.00 (0.00) Hexagrammos decagrammus 0.00 (0.00) Pleuronichthys coenosus 0.07 (0.05) Gibbonsia spp. 0.00 (0.00) Sebastes dalli 0.00 (0.00) Paralabrax clathratus 0.00 (0.00) Unidentified Cottidae 0.00 (0.00) Leiocottus hirundo 0.02 (0.02) Neoclinus blanchardi 0.00 (0.00) Ophiodon elongatus 0.07 (0.05) Paralichthys californicus 0.02 (0.02) Sebastes atrovirens 0.00 (0.00) Unidentified fishes 0.00 (0.00) Gibbonsia spp. 0.00 (0.00) Sebastes carnatus 0.00 (0.00) Paralabrax nebulifer 0.00 (0.00) Pleuronichthys decurrens 0.02 (0.02) Porichthvs spp. 0.00 (0.00) Rathbunella spp. 0.00 (0.00) Sebastes rastrelliger 0.00 (0.00) Urobatis halleri 0.00 (0.00) All fishes 17.76 (5.85) Table 5. Total count across all habitats and mean (SE) number of fishes per transect in each habitat during period when Cable A was surveyed, 14 June 2013-26 February 2014. Two transects, shallow and deep, were surveyed in each habitat on 14 sampling dates. Number of transect surveys in each habitat, n = 28. YOY = young-of-the-year. All Cable A habitats Scientific name Count Mean (SE) Oxvjulis californica 414 3.96 (1.14) Citharichthvs spp. 140 2.14 (0.50) Phanerodon furcatus 241 4.29 (1.29) Cymatogaster aggregate! 56 0.00 (0.00) Sebastes atrovirens, S. 151 1.79 (0.54) caurinus, S. earnatus. or S. chrysomelas YOY Brachvistius frenatus 199 6.18 (2.76) Sebastes miniatus YOY 27 0.36 (0.15) Sebastes jordani YOY 0 0.00 (0.00) Embiotoca jacksoni 104 1.68 (0.70) Aulorhynchus flavidus 7 0.07 (0.05) Hypsurus caryi 123 1.29 (0.30) Damalichthys vacca 23 0.29 (0.15) Sebastes caurinus 54 0.71 (0.27) Sebastes paucispinis 18 0.54 (0.24) Sebastes serranoides or 32 0.43 (0.14) Sebastes flavidus YOY Heterostichus rostratus 22 0.54 (0.18) Sebastes semicinctus 15 0.21 (0.15) Svnodus lucioceps 26 0.79 (0.68) Oxylebius pictus 13 0.29 (0.13) Sebastes mystinus 19 0.36 (0.19) Sebastes auriculatus 2 0.04 (0.04) Scorpaenichthys marmoratus 7 0.00 (0.00) Hexagrammos deeagrammus 10 0.07 (0.05) Pleuronichthys coenosus 6 0.14 (0.08) Gibbonsia spp. 8 0.04 (0.04) Sebastes dalli 5 0.14 (0.14) Paralabrax clathratus 6 0.14 (0.14) Coryphopterus nicholsii 6 0.00 (0.00) Unidentified Cottidae 3 0.00 (0.00) Leiocottus hirundo 2 0.04 (0.04) Neoclinus blanchardi 4 0.07 (0.05) Paralichthys californicus 4 0.00 (0.00) Sebastes atrovirens 1 0.04 (0.04) Syngnathus spp. 3 0.04 (0.04) Sebastes earnatus 1 0.00 (0.00) Cephaloscyllium ventriosum 1 0.00 (0.00) Halichoeres semicinctus 1 0.04 (0.04) Heterodontus Jrancisci 1 0.00 (0.00) Myliobatis californica 1 0.00 (0.00) Phanerodon atripes 1 0.00 (0.00) Unidentified Embiotocidae 1 0.00 (0.00) All fishes 1758 26.86 (4.05) Pipe Scientific name Mean (SE) Oxvjulis californica 8.46 (2.13) Citharichthvs spp. 0.71 (0.20) Phanerodon furcatus 2.75 (1.19) Cymatogaster aggregate! 0.29 (0.29) Sebastes atrovirens, S. 3.50 (0.81) caurinus, S. earnatus. or S. chrysomelas YOY Brachvistius frenatus 0.79 (0.64) Sebastes miniatus YOY 0.43 (0.17) Sebastes jordani YOY 0.00 (0.00) Embiotoca jacksoni 2.00 (0.48) Aulorhynchus flavidus 0.04 (0.04) Hypsurus caryi 2.61 (0.60) Damalichthys vacca 0.46 (0.17) Sebastes caurinus 1.21 (0.42) Sebastes paucispinis 0.00 (0.00) Sebastes serranoides or 0.43 (0.26) Sebastes flavidus YOY Heterostichus rostratus 0.18 (0.07) Sebastes semicinctus 0.32 (0.25) Svnodus lucioceps 0.00 (0.00) Oxylebius pictus 0.18 (0.09) Sebastes mystinus 0.32 (0.22) Sebastes auriculatus 0.04 (0.04) Scorpaenichthys marmoratus 0.21 (0.08) Hexagrammos deeagrammus 0.29 (0.16) Pleuronichthys coenosus 0.04 (0.04) Gibbonsia spp. 0.25 (0.08) Sebastes dalli 0.04 (0.04) Paralabrax clathratus 0.07 (0.05) Coryphopterus nicholsii 0.21 (0.12) Unidentified Cottidae 0.11 (0.08) Leiocottus hirundo 0.04 (0.04) Neoclinus blanchardi 0.07 (0.05) Paralichthys californicus 0.07 (0.05) Sebastes atrovirens 0.00 (0.00) Syngnathus spp. 0.04 (0.04) Sebastes earnatus 0.04 (0.04) Cephaloscyllium ventriosum 0.04 (0.04) Halichoeres semicinctus 0.00 (0.00) Heterodontus Jrancisci 0.04 (0.04) Myliobatis californica 0.00 (0.00) Phanerodon atripes 0.00 (0.00) Unidentified Embiotocidae 0.00 (0.00) All fishes 26.68 (3.47) Natural Scientific name Mean (SE) Oxvjulis californica 2.36 (0.56) Citharichthvs spp. 2.14 (0.48) Phanerodon furcatus 1.57 (0.65) Cymatogaster aggregate! 1.71 (1.43) Sebastes atrovirens, S. 0.11 (0.06) caurinus, S. earnatus. or S. chrysomelas YOY Brachvistius frenatus 0.14 (0.11) Sebastes miniatus YOY 0.18 (0.15) Sebastes jordani YOY 0.00 (0.00) Embiotoca jacksoni 0.04 (0.04) Aulorhynchus flavidus 0.14 (0.07) Hypsurus caryi 0.50 (0.23) Damalichthys vacca 0.07 (0.05) Sebastes caurinus 0.00 (0.00) Sebastes paucispinis 0.11 (0.11) Sebastes serranoides or 0.29 (0.25) Sebastes flavidus YOY Heterostichus rostratus 0.07 (0.05) Sebastes semicinctus 0.00 (0.00) Svnodus lucioceps 0.14 (0.14) Oxylebius pictus 0.00 (0.00) Sebastes mystinus 0.00 (0.00) Sebastes auriculatus 0.00 (0.00) Scorpaenichthys marmoratus 0.04 (0.04) Hexagrammos deeagrammus 0.00 (0.00) Pleuronichthys coenosus 0.04 (0.04) Gibbonsia spp. 0.00 (0.00) Sebastes dalli 0.00 (0.00) Paralabrax clathratus 0.00 (0.00) Coryphopterus nicholsii 0.00 (0.00) Unidentified Cottidae 0.00 (0.00) Leiocottus hirundo 0.00 (0.00) Neoclinus blanchardi 0.00 (0.00) Paralichthys californicus 0.07 (0.07) Sebastes atrovirens 0.00 (0.00) Syngnathus spp. 0.04 (0.04) Sebastes earnatus 0.00 (0.00) Cephaloscyllium ventriosum 0.00 (0.00) Halichoeres semicinctus 0.00 (0.00) Heterodontus Jrancisci 0.00 (0.00) Myliobatis californica 0.04 (0.04) Phanerodon atripes 0.04 (0.04) Unidentified Embiotocidae 0.04 (0.04) All fishes 9.89 (2.15) Table 6. P-values from the repeated measures PERMANOVA testing the effects of habitat (HA), depth (IN), and sampling date (DA) on invertebrate community structure and density of individual taxa and from PERMANOVA pairwise tests for differences between habitats for the periods when Cables B and A were surveyed. Species selected were those that comprised at least 1% of all invertebrates observed. Statistically significant effects and differences are underlined. Cable B HA IN DA Invertebrate community 0.0017 0.2021 0.0238 Taxon: Pisaster spp. 0.0011 0.2884 0.0123 Patina miniata 0.1528 0.9272 0.6332 Aplvsia californica 0.0327 0.4780 0.1149 Kelletia kelletii 0.1097 0.1175 0.1485 Parastichopus spp. 0.3903 0.3395 0.3746 Metacarcinus spp./Cancer spp. 0.0303 0.4645 0.7884 Cable B HAxIN HAxDA INxDA Invertebrate community 0.0365 0.4545 0.1237 Taxon: Pisaster spp. 0.2881 0.0532 0.3558 Patina miniata 0.0046 0.2595 0.1744 Aplvsia californica 0.5209 0.2109 0.0716 Kelletia kelletii 0.6568 0.6353 0.0738 Parastichopus spp. 0.4344 0.5065 0.4964 Metacarcinus spp./Cancer spp. 0.0338 0.8292 0.3765 Cable B Cable, Cable, Pipe, pipe natural natural Invertebrate community 0.0354 0.0610 0.0061 Taxon: Pisaster spp. 0.0196 0.1248 0.0038 Patina miniata Aplvsia californica 0.6433 0.0455 0.0020 Kelletia kelletii Parastichopus spp. Metacarcinus spp./Cancer spp. 0.0650 0.0423 0.8462 Cable A HA IN DA Invertebrate community 0.0001 0.0054 0.0001 Taxon: Pisaster spp. 0.0001 0.0031 0.0015 Patiria miniata 0.0001 0.1323 0.0071 Astropecten armatus 0.0190 0.0205 0.0042 Aplvsia californica 0.0007 0.2111 0.0141 Kelletia kelletii 0.2817 0.6565 0.2405 Parastichopus spp. 0.0001 0.0017 0.0246 Metacarcinus spp./Cancer spp. 0.8382 0.3927 0.4557 Cable A HAxIN HAxDA INxDA Invertebrate community 0.0044 0.2620 0.2436 Taxon: Pisaster spp. 0.0091 0.5799 0.1771 Patiria miniata 0.0008 0.1950 0.0064 Astropecten armatus 0.0573 0.1447 0.4878 Aplvsia californica 0.7424 0.0036 0.8056 Kelletia kelletii 0.7408 0.7233 0.0881 Parastichopus spp. 0.0060 0.0233 0.5548 Metacarcinus spp./Cancer spp. 0.8323 0.9260 0.9788 Cable A Cable, Cable, Pipe, pipe natural natural Invertebrate community 0.0005 0.0001 0.0002 Taxon: Pisaster spp. 0.0009 0.1841 0.0003 Patiria miniata 0.0003 0.0002 0.3001 Astropecten armatus 0.3525 0.0098 0.0855 Aplvsia californica 0.0174 0.0969 0.0009 Kelletia kelletii Parastichopus spp. 0.0004 not defined 0.0002 Metacarcinus spp./Cancer spp. Table 7. Total counts across all habitats and mean (SE) number of invertebrates in each habitat during period when Cable B was surveyed. Two transects, shallow and deep, were surveyed in each habitat on 22 June-15 May 2013 sampling dates. Number of transect surveys in each habitat, n=30. Scientific name Total CABLE B CABLE B count Mean SE Patiria miniata 78 0.43 0.14 Pisaster spp. 70 0.73 0.31 Aplysia californica 19 0.33 0.12 Kelletia kelletii 27 0.37 0.19 Parastichopus sp. 1 0.00 0.00 Metacarcinus sp. and Cancer sp. 18 0.47 0.18 Loligo opalescens eggs 20 0.00 0.00 Pugettia spp. 18 0.30 0.13 Loxorhvnchus spp. 12 0.10 0.06 Dendraster excentricus 19 0.10 0.07 Octopus spp. 2 0.03 0.03 Metacarcinus gracilis 5 0.07 0.07 Dermasterias imhricata 3 0.10 0.10 Megathura cremdata 1 0.00 0.00 Pycnopodia helianthoides 1 0.03 0.03 Scientific name Pipe Pipe Natural Natural Mean SE Mean SE Patiria miniata 0.97 0.29 1.20 0.32 Pisaster spp. 1.27 0.25 0.33 0.14 Aplysia californica 0.27 0.11 0.03 0.03 Kelletia kelletii 0.03 0.03 0.50 0.22 Parastichopus sp. 0.03 0.03 0.00 0.00 Metacarcinus sp. and Cancer sp. 0.07 0.05 0.07 0.07 Loligo opalescens eggs 0.67 0.67 0.00 0.00 Pugettia spp. 0.27 0.14 0.03 0.03 Loxorhvnchus spp. 0.13 0.06 0.17 0.08 Dendraster excentricus 0.03 0.03 0.50 0.28 Octopus spp. 0.00 0.00 0.03 0.03 Metacarcinus gracilis 0.07 0.07 0.03 0.03 Dermasterias imhricata 0.00 0.00 0.00 0.00 Megathura cremdata 0.03 0.03 0.00 0.00 Pycnopodia helianthoides 0.00 0.00 0.00 0.00 Table 8. Total counts across all habitats and mean (SE) number of invertebrates in each habitat during period when Cable A was surveyed. Two transects, shallow and deep, were surveyed in each habitat on 14 June 2013-26 February 2014 sampling dates. Number of transect surveys in each habitat, n=28. Scientific name Total CABLE A CABLE A count Mean SE Patiria miniata 155 0.75 0.26 Pisaster spp. 92 0.46 0.17 Strongylocentrotus purpuratus 100 0.00 0.00 Aplvsia californica 44 0.29 0.12 Astropecten armatus 51 0.29 0.10 Kelletia kelletii 21 0.04 0.04 Parastichopus sp. 21 0.04 0.04 Metacarcinus sp. and Cancer sp. 4 0.07 0.05 Pugettia spp. 1 0.00 0.00 Loxorhvnchus spp. 7 0.04 0.04 Octopus spp. 10 0.07 0.07 Dermasterias imhricata 1 0.00 0.00 Pamdirus interruptus 1 0.04 0.04 Scientific name Pipe Pipe Natural Natural Mean SE Mean SE Patiria miniata 2.14 0.38 2.64 0.41 Pisaster spp. 2.61 0.66 0.21 0.08 Strongylocentrotus purpuratus 3.57 3.57 0.00 0.00 Aplvsia californica 1.25 0.44 0.04 0.04 Astropecten armatus 0.43 0.12 1.11 0.37 Kelletia kelletii 0.46 0.33 0.25 0.15 Parastichopus sp. 0.68 0.18 0.04 0.04 Metacarcinus sp. and Cancer sp. 0.04 0.04 0.04 0.04 Pugettia spp. 0.00 0.00 0.04 0.04 Loxorhvnchus spp. 0.11 0.06 0.11 0.08 Octopus spp. 0.29 0.10 0.00 0.00 Dermasterias imhricata 0.00 0.00 0.04 0.04 Pamdirus interruptus 0.00 0.00 0.00 0.00 Table 9. P-values from the repeated measures PERMANOVA testing the effects of habitat (HA), depth (IN), and sampling date (DA) on macrophyte community structure and density of individual taxa and from PERMANOVA pairwise tests for differences between habitats for the periods when Cables B and A were surveyed. Statistically significant effects and differences are underlined. Cable B HA IN DA Macrophyte community 0.0001 0.0001 0.0001 Taxon: Zostera marina 0.0001 0.2553 0.0659 Pterygophora californica 0.0001 0.0001 0.0676 Cvstoseira spp. 0.0001 0.0026 0.0019 Laminaria spp. 0.0001 0.0001 0.1713 Cable B HAxIN HAxDA INxDA Macrophyte community 0.0001 0.0003 0.0002 Taxon: Zostera marina 0.3820 0.1259 0.3389 Pterygophora californica 0.0001 0.1672 0.5020 Cvstoseira spp. 0.0001 0.0001 0.1156 Laminaria spp. 0.0001 0.0574 0.0395 Cable B Cable, Cable, Pipe, pipe natural natural Macrophyte community 0.0001 0.0001 0.0001 Taxon: Zostera marina 0.0001 0.0001 0.0001 Pterygophora californica 0.0001 0.0001 0.0001 Cvstoseira spp. 0.0001 0.0001 0.0001 Laminaria spp. 0.0037 0.0001 0.0001 Cable A HA IN DA Macrophyte community 0.0001 0.0001 0.0477 Taxon: Zostera marina 0.0001 0.0001 0.0215 Pterygophora californica 0.0001 0.0001 0.6193 Cvstoseira spp. 0.0001 0.2970 0.0762 Laminaria spp. 0.0001 0.0001 0.8647 Macrocystis pvrifera 0.0001 0.0001 0.0654 Cable A HAxIN HAxDA INxDA Macrophyte community 0.0001 0.0054 0.2401 Taxon: Zostera marina 0.0001 0.0720 0.4107 Pterygophora californica 0.0001 0.5937 0.1637 Cvstoseira spp. 0.0001 0.6016 0.2163 Laminaria spp. 0.0001 0.9155 0.2615 Macrocystis pvrifera 0.0001 0.5037 0.0599 Cable A Cable, Cable, Pipe, pipe natural natural Macrophyte community 0.0001 0.0001 0.0001 Taxon: Zostera marina 0.0001 0.0001 0.0001 Pterygophora californica 0.0001 0.0001 0.0001 Cvstoseira spp. 0.0001 0.0001 0.0001 Laminaria spp. 0.2039 0.0001 0.0001 Macrocystis pvrifera 0.0001 0.0001 0.0001 Table 10. Total count across all habitats and mean (SE) number of macrophytes per transect in each habitat during period when cable B and cable A were surveyed, 1 February 2012-15 May 2013 and 14 June 2013-26 February 2014, respectively. Two transects, shallow and deep, were surveyed in each habitat on each date. Number of transect surveys in each habitat when Cable B and Cable A were surveyed, n=46 and n=28, respectively. Cable B Total Cable Cable Count Mean SE Zostera marina 19453 16.96 3.41 Pteiygophora californica 16490 344.98 36.11 Cystoseira spp. 5223 15.65 2.50 Macrocystis pyrifera 329 3.54 1.37 Laminaria spp. 2123 18.26 3.05 Cable B Pipe Pipe Natural Natural Mean SE Mean SE Zostera marina 0.00 0.00 405.93 28.21 Pteiygophora californica 13.50 2.55 0.00 0.00 Cystoseira spp. 97.89 6.02 0.00 0.00 Macrocystis pyrifera 3.61 1.37 0.00 0.00 Laminaria spp. 27.89 4.34 0.00 0.00 Cable A Total Cable Cable Count Mean SE Zostera marina 22791 14.36 2.97 Pteiygophora californica 886 20.29 1.11 Cystoseira spp. 2943 17.11 1.97 Macrocystis pyrifera 5228 163.07 33.66 Laminaria spp. 892 12.39 2.61 Cable A Pipe Pipe Natural Natural Mean SE Mean SE Zostera marina 0.07 0.07 799.54 50.88 Pteiygophora californica 11.36 2.33 0.00 0.00 Cystoseira spp. 88.00 8.43 0.00 0.00 Macrocystis pyrifera 23.64 5.14 0.00 0.00 Laminaria spp. 19.46 3.80 0.00 0.00
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|Author:||Love, Milton S.; Nishimoto, Mary M.; Clark, Scott; McCrea, Merit; Bull, Ann Scarborough|
|Publication:||Bulletin (Southern California Academy of Sciences)|
|Date:||Aug 1, 2017|
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