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Seamounts in the southeastern Pacific Ocean and biodiversity on Juan Fernandez seamounts, Chile/Montes submarinos en el oceano Pacifico suroriental y biodiversidad en el cordon de Juan Fernandez, Chile.

INTRODUCTION

The marine environment is currently under serious depletion as a result of overfishing, contamination, and the direct and indirect impacts of climate changes. The anthropogenic and climate impacts observed in many places have caused dramatic changes in ecosystems. This is the case of seamounts, vulnerable marine ecosystems in which a decrease of biostructure-forming species and a collapse of oceanic fisheries have been observed. The vulnerability of these ecosystems is related to the possibility that a population, community, or habitat will experience a substantial alteration, which may be irreversible or of slow restoration (FAO, 2007). The international information on seamount biodiversity and ecology is limited, especially for those at depths exceeding 300 m (Tracey et al., 2004). Therefore, although thousands of seamounts are estimated to exist around the world, only around 200 have been biologically sampled, in most cases, during commercial fishing activities (Probert et al., 1997; Galvez et al., 2006).

In Chile, there is lack of information for an undetermined number of seamounts in the Economic Exclusive Zone (EEZ). Research on seamount biodiversity along the Chilean coast has been carried out since 1950, mainly by the Russian government on the Nazca and Salas and Gomez ridges, beyond the EEZs of Chile and Peru (Parin et al., 1997). The information on the Juan Fernandez Archipelago (33[degrees]S-78[degrees]W) is limited to the H.M.S. Challenger scientific expedition (1873-1876), the Pacific Swedish expedition (19161917), and the B/I Anton Bruun expedition (1966) (Rozbaczylo & Castilla, 1987), as well as the oceanographic cruises MARCHILE VIII and IX of 1972 and 1973, respectively (Cerda, 1977), the CIMAR 5 and 6 Oceanic Islands cruises in 1999 and 2000 (Rojas et al., 2004), and the scientific survey of B/I Koyo Maru in 2004 (Zuleta & Hamano, 2004). Furthermore, information has been systematically collected on fauna associated with bottom dredges over Chilean seamounts (Galvez et al., 2006).

The objective of this work, considering the international demand for information on vulnerable marine ecosystems such as seamounts (Resolution 59/25 of the ONU General Assembly), is to determine the geographical distribution of seamounts in the Chilean EEZ, including a biodiversity and fishing impact study on some seamounts of the Juan Fernandez Archipelago.

MATERIALS AND METHODS

The geographical seamount identification and distribution was determined through the analysis of images generated using 2' x 2' resolution satellite altimetry data (Smith & Sandwell, 1997) and 1' x 1' resolution sounding data (GEBCO, 2003), according to the Kitchingman & Lai methodology (2004). Furthermore, in situ assessments were carried out on two seamounts of the Juan Fernandez Archipelago--Juan Fernandez 1 (JF1) and Juan Fernandez 2 (JF2)--through two exploratory campaigns at 247 and 292 m depth, the respective depths of their tops. The first was executed aboard the PAM Portugal II in July-August 2007, and the second was carried out aboard two artisanal boats in November-December 2007: Boat No. 58 Cumberland and L/M Alborada. All the relatively flat area accessible for fishing and sampling systems (over 700 m deep) was systematically gridded (0.5 x 0.5 tenths of degrees), and a grid was randomly selected for sampling.

Three different depth strata were analyzed: pelagic, demersal, and benthic. Different fishing systems were also used: vertical longlines (1,264 hooks), handlines (12 hooks), fishing pots (108 traps), surface longlines (440 hooks), zooplankton nets (10 haul), dredging (5 haul), submarine camera observations (4 observation periods), and oceanographic surveys of the water column (CTD and Niskin Bottles). The surface oceanographic characteristics were analyzed using satellite information (NOAA, TOPEX, SeaWins, SeaWifs).

Additionally, a bibliographical analysis was done to determine the different species previously collected during surveys, cruises, and commercial fishing activities carried out on these seamounts. Finally, an evaluation of the fishing effects index (FEI) (O'Driscoll & Clark, 2005) was done in the same area of study. This index involves data on the fishing effort executed on each seamount, the direction of the trawling, and the seamount area. On one hand, this index measures the fishing density on a seamount as a proportion of its area; on the other hand, it reflects a scale factor that is proportional to the directions the seamount was trawled. A high FEI value may be explained through a heavy effort relative to the seamount size and the fact it was trawled in all directions. The information used for this analysis corresponds to data from fishing binnacles of the industrial trawling fleet operating over orange roughy (Hoplostethus atlanticus) and alfonsino (Beryx splendens) between 2000 and 2006. The same data was used to analyze the spatial structure dynamics of the resources in 2001 and 2003 through geostatistical techniques.

RESULTS

A total of 118 seamounts were identified in seven areas of the Chilean EEZ (Fig. 1): 35 around Easter Island (25[degrees]-30[degrees]S, 105[degrees]-112[degrees]W) (Fig. 2), 21 near San Felix Island (24[degrees]-29[degrees]S, 76[degrees]-84[degrees]W) (Fig. 3), 21 off northern Chile (18[degrees]-30[degrees]S, 71[degrees]-75[degrees]W) (Fig. 4), 15 around the Juan Fernandez Archipelago (30[degrees]-35[degrees]S, 76[degrees]-82[degrees]W) (Fig. 5), eight in the central area of the country (30[degrees]-40[degrees]S, 71[degrees]-76[degrees]W) (Fig. 6), nine in the southern area (40[degrees]-50[degrees]S, 73[degrees]-79[degrees]W) (Fig. 7), and 10 off far-southern Chile (50[degrees]-58[degrees]S, 70[degrees]-77[degrees]W) (Fig. 8). This identification included the geographical location, surface area, and depth of these seamount tops and the designation of codified names (see Yanez et al. 2008 for details).

[FIGURE 1 OMITTED]

Seamounts JF1 and JF2 have volcanic substrate, which is mainly constituted by bare rock and sand. These seamounts are influenced by several water masses: Subtropical Water (STW), Subantarctic Water (SAAW), Equatorial Subsurface Water (ESSW), and Antarctic Intermediate Water (AAIW), but are predominantly influenced by SAAW and STW (Fig. 9). The vertical distribution of dissolved oxygen showed a two-layer structure. The well-oxygenated surface structure of approximately 100 m with concentrations greater than 5 mL [L.sup.-1] (90-100% saturation) is the result of oxygen-atmosphere exchange and primary production in the area. Beneath this layer and at approximately 200 to 300 m depth, the dissolved oxygen was quickly reduced to concentrations of less than 1 mL [L.sup.-1] (5-20% saturation); the latter drop was caused by the presence of ESSW coming from off Peru (Fig. 10). A slight current system was observed in July-August (winter) with sea surface temperature (SST) anomalies that were negative at JF1 and positive at JF2. The SST showed a typical cold condition of 10[degrees] to 17[degrees]C, surface salinity of approximately 34.3, and chlorophyll concentrations between 0.09 and 1 mg [m.sup.-3]. In November-December (spring), however, a greater amount of mesoscale structures such as shifts and currents were observed. The STW showed a cold condition that is typical of the season, with SST of 13 to 18[degrees]C; surface salinity close to 34.1, and a chlorophyll-[alpha] concentration around 4 mg [m.sup.-3].

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The phytoplankton collected on the surveyed seamounts involved seven classes of organisms that were classified into 31 genera, 23 species, and other non-identified species. Fifty percent of the organisms were classified as "other flagellates", another 40% corresponded to the Dinophyceae class, and the remaining 7% included the Bacillariophyceae (3.3%), Ciliata (2.1%), Cianophyceae (1.4%), Dictyochophyceae (0.15%), Chlorophyceae (0.04%), and Acantharia (0.01%) (Table 1). Meanwhile, a total of 52,309 organisms were identified as zooplankton; these were distributed among 16 taxonomic groups belonging to the phyla Cnidaria, Ctenophora, Chaetognatha, Annelida, Nemertina, Arthropoda, Tunicata, and Vertebrata. An 87.8% of the organisms were chitinous (euphausiids, mysids, amphipods, ostracods, copepods, cirripedia, decapod crustacean larvae), 11.6% were gelatinous and semi-gelatinous (jellyfish, siphonophores, ctenophores, chaetognaths, salps, appendicularians, polychaetes, nemertins) and the remaining 0.6% corresponded to ichthyoplankton (Hygophum brunni, Sardinops sagax) (Table 2).

The fishing methods allowed catches of two pelagic species, blue shark (Prionace glauca) and snoek (Thyrsites atun); two demersal species, croaker (Helicolenus lengerichi) and depth conger (Pseudoxenomystax nielseni); and two crustacean species, golden crab (Chaceon chilensis) and Juan Fernandez king crab (Paromola rathbuni). A total of 409 invertebrates were collected using a dredge. These represented important groups of species such as Echinoidea (Echinacea), Polychaeta, Porifera, Actinaria, and Asteroidea (Table 3). Due to the complexity of the identification, only two taxa have been identified to this date: 1) Asteroidea new species of Smilasterias and 2) Gorgonia species Callogorgia kinoshitae (Kukenthal, 1913). Only preliminary results are available for other species.

The bibliographical review established that, during the 2001 to 2006 fishing activities, a total of 82 species were collected from the JF1 and JF2 seamounts; these belonged to four phyla (Chordata, Arthropoda, Mollusca, Echinodermata) and the families Macrouridae (9), Moridae (6), and Dalatiidae (4) stood out. The presence of black coral species (Parantipahes fernandenzii, Trisopathes spp., Leiopathes spp.) in lobster traps used around the Juan Fernandez Archipelago deserve mention (Arana et al., 2006).

Submarine images of the JF1 and JF2 marine substrate showed characteristics ascribed to the impact of bottom dredges, coinciding with the information from the trawling fleet, whose activity was primarily executed on the flat surface area of the seamounts (Galvez et al., 2006). When analyzed, this information revealed that the fishing activity was mainly concentrated on the JF2 seamount, reaching 4,667 km of trawling; in comparison, trawling on the JF1 and JF4 seamounts reached values of 1,526 km and 906 km, respectively. In spite of these results, the FEI showed higher values for seamounts JF4 and JF2 (10.5 [km.sup.-1] and 11.7 [km.sup.-1], respectively) than for JF1. Although heavy fishing activity was executed on the latter, its FEI was 2.51 [km.sup.-1] due to its larger area, which is estimated to be 608 [km.sup.2] (Table 4).

In general terms, the fishing effort, measured as the total trawling distance, increased considerably in 2002, 2003, and 2005, with values that exceeded the 500 km of trawling. Later, a considerable decrease was observed by the end of the analyzed period (2001-2006), followed by the same values observed at the beginning of the fishing activity. The high level of observed fishing effort seems to have modified the spatial structure of the resource aggregates exploited at the JF2 seamount. In 2001, the aggregates at this seamount showed a symmetrical spatial distribution up to 4 km; however, that value that did not exceed 1 km in 2003 (Fig. 11). The spatial variability was affected by a decrease in the relative abundance of the resources exploited on this seamount (orange roughy and alfonsino) (Fig. 12).

[FIGURE 11 OMITTED]

[FIGURE 12 OMITTED]

DISCUSSION

A total of 118 seamounts were identified in the continental and insular EEZ of Chile. A method similar to that used by Kitchingman & Lai (2004) was put into practice, considering statistical (standard deviation, filters, hillshading) and visual (judgment, 3D cartography) analyses for the identification of potential seamounts. The number of identified seamounts is influenced by the depth standard deviation as well as filter size and type (kernel 5 * 5 nearest-neighbor) and visual analysis criteria. Furthermore, the identification sensitivity is directly affected by the spatial resolution of the bathymetric data.

The information on the diversity of the phytoplankton organisms collected in the area, along with the data analyzed by Pizarro et al. (2006), allow the preliminary inference that the nano- and microplankton structure detected with the analysis of the water samples collected in late winter 2007 indicate the presence of a clearly oligotrophic environment. Small organisms predominate such environments and the systems are mainly supported by regenerated production and the probable entry of allochthonous nutrients from adjacent islands or elements advected from the seamounts or the coastal areas of Chile through large upwelling plumes that are generally observed on satellite images. Regarding the diversity of zooplankton organisms, most species and/or genera identified around the seamounts corresponded to organisms that are characteristic of the oceanic waters of the Humboldt Current System, which are found in low densities off the coast. The taxonomic composition of the zooplankton in this area is characterized by the presence of copepods (84.4% zooplankton), which coincides with results for oceanic waters in similar ecosystems of other oceans (Schnack-Schiel & Mizdalski, 2002). The quantity of zooplankton was quite scarce, in agreement with the low densities reported around the Juan Fernandez Archipelago (Palma, 1985) and the oceanic waters along the Chilean coast (Palma & Silva, 2006), and with other studies that have shown low densities on seamounts with abrupt topographies. This contradicts the results of Schwartz (2005) for seamounts from the Eastern Central Pacific. In fact, the biomass values were quite low compared to those detected in Chile's coastal waters.

The diversity of pelagic, demersal, and benthic organisms from this area was restricted to four fish species and two crustacean species. This was basically due to the fishing systems used in the surveys, which prioritized direct, non-intrusive sampling methods such as submarine images and gears like traps and longlines. One fish was the blue shark (Prionace glauca), a species considered to be epipelagic and of circumpolar distribution (Compagno, 1984). This shark is abundant in the southeastern Pacific and is captured by multiple fleets using surface longlines. The sawfish (Thyrsites atun), on the other hand, is considered to be a benthopelagic fish with a well-known distribution on continental shelves or around islands (Nakamura & Parin, 1993). Among demersal fish, the croaker (Helicolenus lengerichi) has been cited as one of the five species of the Scorpaenidae family present around the Juan Fernandez Archipelago (Pequeno & Saez, 2000), whereas the conger Bassanago albescens has been caught with a low incidence (Lillo et al., 1999) as part of the by-catch of orange roughy fishing activities on Juan Fernandez seamounts.

The golden crab (Chaceon chilensis) and the Juan Fernandez king crab (Paromola rathbuni) have been cited as two of the five decapod crustacean species captured during surveys and experimental trap fishing activities around Robinson Crusoe and Santa Clara islands (Retamal & Arana, 2000). The presence of the Juan Fernandez king crab was originally reported for the Juan Fernandez Archipelago (Retamal, 1981) and the Desventuradas Islands (Baez & Ruiz, 1985) and is considered to be endemic to this area of the southeastern Pacific. This decapod is distributed between 100 and 300 m depth, with a greater abundance at 200 m around Robinson Crusoe and Santa Clara islands (Retamal & Arana, 2000). Furthermore, the golden crab has been reported off Zapallar and Quintero, along the central coast of continental Chile (Baez & Andrade, 1977; Andrade & Baez, 1980; Andrade, 1987), the Juan Fernandez Archipelago and San Felix and San Ambrosio islands (Retamal, 1981; Chirino-Galvez & Manning, 1989), and along the undersea Nazca Ridge mainly at 90[degrees]W (Parin et al., 1997). The golden crab is generally distributed between 200 m and 2,000 m of depth (Dawson & Webber, 1991). It was found at depths of 400 and 800 m along the undersea Nazca Ridge (Parin et al., 1997) and was caught at 100 and 1,000 m around Robinson Crusoe and Santa Clara islands, with a greater abundance at 300 m and between 500 and 600 m (Arana, 2000).

The submarine images of the plains of seamounts JF1 and JF2 (up to 600 m approximately) suggest the presence of a marine substrate with similar characteristics to those reported in the literature for places that have been strongly impacted by trawling gears (FAO, 2007; Clark & Koslow, 2007).

Johnston & Santillo (2004) have suggested that sustainable seamount fisheries require good knowledge of the biology and ecology of the species to be exploited. Regarding the orange roughy fisheries on seamounts within the Chilean EEZ, there has been a trend towards increased global quotas in spite of the ignorance regarding the stock abundance at the Juan Fernandez Archipelago (Young et al., 2000; Galvez et al., 2006). Despite this increase, the quota has never been totally extracted and the landing proportion has been observed to decrease.

The FEI provides a measure of relative intensity of the trawling fishing activities on a seamount, thereby allowing the categorization of the seamounts according to trawling density and direction. Due to the fact that the trawling was reported to last close to a minute and the trawling velocity is generally constant, then the trawling length estimation offers an adequate indicator of the scanned area. The distribution of the trawling direction on the studied seamounts was not random, suggesting that the fishermen have some degree of knowledge and, thus, prefer certain areas (trawling routes), whereas other adjacent areas do not seem to be affected by fishing activities. O'Driscoll & Clark (2005) have suggested that the FEI cannot directly assess the fishing impact on a seamount. Therefore, it should be necessarily related to other ecological indexes in order to obtain an ecological impact index of the trawling fishing over the substrate and associated fauna that could vary according to the substrate and fishing intensity.

Furthermore, strong spatial variability of the relative densities of the fishing resources associated with seamount JF2 in 2001 and 2003 was observed. This spatial variability was associated with a decrease in the relative abundance of the two main fishing resources exploited on this seamount (orange roughy and alfonsino) and a strong spatial contraction of said resources, which was represented by a significant change in the variogram range. The effect of the commercial exploitation on seamount JF2 caused an 85% reduction in the range of values between 2001 and 2003. Pankhurst (1998) indicated that orange roughy aggregates in the same period and place on the seamounts of New Zealand, which makes it quite predictable. These dense aggregations cause an elevated backscattered acoustic amplitude that is easily identified. Thus, the resource is highly vulnerable to commercial fishing. Besides, it has also been suggested that, during productive periods, orange roughy aggregations tend to remain still during certain periods or even for many days (Bull et al., 2001).

One of the objectives of the current international approach for marine biodiversity conservation is the identification and protection of the discrete areas that are defined from the representativeness of the existing ecosystems and/or their role as an essential habitat for the conservation of vulnerable or threatened species. Therefore, the demand for the identification and prioritization of possible protected marine areas in the Chilean seamounts requires some knowledge of the structure and singularity of its communities and the role such areas play in the life cycle of the species identified as special conservation subjects. In this sense, the extent of the knowledge necessary for the adequate conservation of biodiversity on seamounts in the Chilean EEZ is huge and this study is just one step towards an increase in the available information. Obviously, most attention is directed towards those areas currently under fishing exploitation, where it is crucial to take conservation measures for the development of sustainable activities.

DOI: 10.3856/vol37-issue3-fulltext-20

ACKNOWLEDGEMENTS

The authors would like to thank the crews of PAM Portugal II, the L/M Alborada, and the boat Cumberland for their great disposition and assistance with the works carried out on board. Furthermore, we wish to thank the Fondo de Investigacion Pesquera de Chile for their support of FIP project No. 2006-57.

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Received: 11 May 2009; Accepted: 1 October 2009

Eleuterio Yanez (1), Claudio Silva (1), Rodrigo Vega (2), Fernando Espindola (3), Lorena Alvarez (1), Nelson Silva (1), Sergio Palma (1), Sergio Salinas (1), Eduardo Menschel (2), Verena Haussermann (4), Daniela Soto (1) & Nadin Ramirez (1)

(1) Pontificia Universidad Catolica de Valparaiso, P.O. Box 1020, Valparaiso, Chile

(2) Universidad Austral de Chile, P.O. Box 567, Valdivia, Chile

(3) Instituto de Fomento Pesquero, P.O. Box 8-V, Valparaiso, Chile

(4) Fundacion Huinay, P.O. Box 462, Puerto Montt, Chile
Table 1. Composition and abundance of nano-microplankton (cel
[L.sup.-1]) on the seamounts Juan Fernandez 1 and Juan Fernandez 2.
Only the mean of each taxonomic group is indicated.

Tabla 1. Composicion y abundancia de nano-microplancton (cel
[L.sup.-1]) en los montes submarinos Juan Fernandez 1 y Juan
Fernandez 2. Se indica el promedio de cada grupo.

                            Station         1             2

                            Depth (m)    0      50     0      50
Species
Acantharia                               0      20     0      0
Nasselaria                               0      20     0      0
Bacillariophyceae                        60    140    1040   180
Bacteriastrum sp.                        0      0      0      0
Chaetoceros atlanticus                   0      0      0      0
Chaetoceros peruvianus                   0      0      0      0
Chaetoceros spp.                         0      0      0      0
Cylindrotheca closterium                 0      0      40     0
Dactyliosolen sp.                        20     0      0      0
Nitszchia longissima                     0      0      40     0
Nitszchia spp.                           0      0      0      0
Pennadas indeterminates                  20     80     80     40
Pleurosigma spp.                         0      0      0      0
Pseudonitzschia spp.                     0      60    840    140
Rhizosolenia alata                       0      0      0      0
Rhizosolenia bergonii                    0      0      40     0
Rhizosolenia spp.                        20     0      0      0
Thalassiothrix sp.                       0      0      0      0
Cianophyceae                             0      0     480    1820
Ciliata                                 140    160    600    160
Acanthostomella                          0      0      0      0
  norvegica ?
Ascampbeliella sp.                       0      0      0      0
Ciliates (> 15 [micro]m)                 40     60    200    140
Ciliates (< 15 [micro]m)                 0      0      0      0
Dictiocysta elegans                      0      20     40     20
Dictiocysta mitra                        0      0      0      0
Dictiocysta sp.                          40     0      80     0
Eutintinnus fraknoi                      0      20     0      0
Eutintinnus lusus-undae                  20     20    200     0

Laboea spp.                              0      0      0      0
Parundela caudata                        0      20     0      0
Protorhabdonella curta                   0      0      0      0
Rhabdonella chilensis                    20     0      40     0
Rhabdonella sp.                          20     0      0      0
Salpinguella sp.                         0      20     0      0
Steentrupiella pozzi                     0      0      40     0
Undella sp.                              0      0      0      0
Undella claparedei                       0      0      0      0
Xystonella treforti                      0      0      0      0
Dictyochophyceae                         20     0      40     20
Dictyocha fibula                         20     0      0      0
Dictyocha sp.                            0      0      40     20
Dictyocha speculum                       0      0      0      0
Dinophyceae                             2039   5038   8677   8937
Ceratium extensum                        0      0      0      0
Ceratium furca                           40     40     0      40
Ceratium fusus                           40     40     80     20
Ceratium tripos                          0      0      0      0
Athecate dinoflagellates                100    280    200    380
  (> 15 [micro]m)
Athecate dinoflagellates                1839   4598   8277   8277
  (< 15 [micro]m)
Thecate dinoflagellates                  0      0      0      20
Dinophysis sp.                           0      0      0      0
Dissodinium sp.                          0      0      40     0
Gonyaulax polygramma                     0      20     0      0
Ornithocercus sp.                        0      0      0      0
Oxytosum sp.1                            20     60     40    100
Oxytosum sp.2                            0      0      40     60
Podolampas sp.                           0      0      0      40
Prorocentrum sp.                         0      0      0      0
Protoperidinium conicum                  0      0      0      0
Protoperidinium sp.                      0      0      0      0
Scripsiella sp.                          0      0      0      0
Flagellata                              2759   2759   2759   4139
Flagellates/Ciliates                     0      0      0      0
  (< 10 [micro]m)
Flagellates                             2759   2759   2759   4139
  (< 10 [micro]m)

                            Station          3            4

                            Depth (m)    0      50      0     50
Species
Acantharia                               0      0       0      -
Nasselaria                               0      0       0     s/i
Bacillariophyceae                       880    960     320     -
Bacteriastrum sp.                        80     0       0     s/i
Chaetoceros atlanticus                   0      0       0     s/i
Chaetoceros peruvianus                   0      0       0     s/i
Chaetoceros spp.                         0      0       0     s/i
Cylindrotheca closterium                 0      0       0     s/i
Dactyliosolen sp.                        0      80      0     s/i
Nitszchia longissima                     40     0       0     s/i
Nitszchia spp.                           0      0       0     s/i
Pennadas indeterminates                 180     80     80     s/i
Pleurosigma spp.                         0      0       0     s/i
Pseudonitzschia spp.                    500    760     200    s/i
Rhizosolenia alata                       20     0       0     s/i
Rhizosolenia bergonii                    40     0       0     s/i
Rhizosolenia spp.                        0      40      0     s/i
Thalassiothrix sp.                       20     0      40     s/i
Cianophyceae                             0      0      780    s/i
Ciliata                                 540    200     320     -
Acanthostomella
  norvegica ?                            0      0       0     s/i
Ascampbeliella sp.                       0      0      20     s/i
Ciliates (> 15 [micro]m)                320     0      160    s/i
Ciliates (< 15 [micro]m)                 0      0       0     s/i
Dictiocysta elegans                      0      0       0     s/i
Dictiocysta mitra                        0      0      40     s/i
Dictiocysta sp.                          20     0       0     s/i
Eutintinnus fraknoi                      40     0       0     s/i
Eutintinnus lusus-undae                  80    160     40     s/i
Laboea spp.                              40     0      20     s/i
Parundela caudata                        0      0       0     s/i
Protorhabdonella curta                   0      0       0     s/i
Rhabdonella chilensis                    0      0      40     s/i
Rhabdonella sp.                          0      0       0     s/i
Salpinguella sp.                         40     40      0     s/i
Steentrupiella pozzi                     0      0       0     s/i
Undella sp.                              0      0       0     s/i
Undella claparedei                       0      0       0     s/i
Xystonella treforti                      0      0       0     s/i
Dictyochophyceae                         40     0       0
Dictyocha fibula                         40     0       0     s/i
Dictyocha sp.                            0      0       0     s/i
Dictyocha speculum                       0      0       0     s/i
Dinophyceae                             7897   3959   10417    -
Ceratium extensum                        0      0       0     s/i
Ceratium furca                           40     40      0     s/i
Ceratium fusus                           80     80     120    s/i
Ceratium tripos                          0      0       0     s/i
Athecate dinoflagellates                320     40     460    s/i
  (> 15 [micro]m)
Athecate dinoflagellates                7357   3679   9657    s/i
  (< 15 [micro]m)
Thecate dinoflagellates                  0      0       0     s/i
Dinophysis sp.                           0      0       0     s/i
Dissodinium sp.                          0      0       0     s/i
Gonyaulax polygramma                     0      0       0     s/i
Ornithocercus sp.                        0      0       0     s/i
Oxytosum sp.1                            80     0      20     s/i
Oxytosum sp.2                            20    120     160    s/i
Podolampas sp.                           0      0       0     s/i
Prorocentrum sp.                         0      0       0     s/i
Protoperidinium conicum                  0      0       0     s/i
Protoperidinium sp.                      0      0       0     s/i
Scripsiella sp.                          0      0       0     s/i
Flagellata                              5058   4598   13795    -
Flagellates/Ciliates
  (< 10 [micro]m)                        0      0       0     s/i
Flagellates                             5058   4598   13795   s/i
  (< 10 [micro]m)

                            Station           5               6

                            Depth (m)     0       50      0      50
Species
Acantharia                                0       0       0       0
Nasselaria                                0       0       0       0
Bacillariophyceae                        620     540      20     160
Bacteriastrum sp.                         0       0       0       0
Chaetoceros atlanticus                   120      0       0       0
Chaetoceros peruvianus                    0       0       0       0
Chaetoceros spp.                         40       0       0       0
Cylindrotheca closterium                 20       20      0       0
Dactyliosolen sp.                        20       0       0       0
Nitszchia longissima                      0       0       0       0
Nitszchia spp.                            0       0       0       0
Pennadas indeterminates                  40      320      20     40
Pleurosigma spp.                          0       0       0       0
Pseudonitzschia spp.                     140      0       0      40
Rhizosolenia alata                        0       0       0       0
Rhizosolenia bergonii                    20       0       0       0
Rhizosolenia spp.                        220     200      0      80
Thalassiothrix sp.                        0       0       0       0
Cianophyceae                              0       0       0       0
Ciliata                                 1837     3299    560     80
Acanthostomella                           0       0       0       0
  norvegica ?
Ascampbeliella sp.                        0       0       0       0
Ciliates (> 15 [micro]m)                 740     440     500     80
Ciliates (< 15 [micro]m)                 920     2759     0       0
Dictiocysta elegans                       0       0       0       0
Dictiocysta mitra                        40       40      0       0
Dictiocysta sp.                           0       0       0       0
Eutintinnus fraknoi                       0       0       0       0
Eutintinnus lusus-undae                  20       40      0       0
Laboea spp.                               0       0       20      0
Parundela caudata                        40       0       20      0
Protorhabdonella curta                    0       0       0       0
Rhabdonella chilensis                     0       0       0       0
Rhabdonella sp.                           0       0       0       0
Salpinguella sp.                          0       0       0       0
Steentrupiella pozzi                     20       20      20      0
Undella sp.                               0       0       0       0
Undella claparedei                       20       0       0       0
Xystonella treforti                       0       0       0       0
Dictyochophyceae                         20       20      60      0
Dictyocha fibula                          0       20      0       0
Dictyocha sp.                             0       0       40      0
Dictyocha speculum                       20       0       20      0
Dinophyceae                             11456   16336    6438   5958
Ceratium extensum                         0       20      20      0
Ceratium furca                           20       40      20     20
Ceratium fusus                           40      160      0      80
Ceratium tripos                          20       0       0       0
Athecate dinoflagellates                 240     380     580     300
  (> 15 [micro]m)
Athecate dinoflagellates                11036   11956    5518   5518
  (< 15 [micro]m)
Thecate dinoflagellates                  20       0       0       0
Dinophysis sp.                           20       0       0       0
Dissodinium sp.                           0       0       0       0
Gonyaulax polygramma                     20       0       0       0
Ornithocercus sp.                         0       0       0       0
Oxytosum sp.1                            20       40     160     20
Oxytosum sp.2                             0       40     140     20
Podolampas sp.                            0       0       0       0
Prorocentrum sp.                          0       0       0       0
Protoperidinium conicum                  20       0       0       0
Protoperidinium sp.                       0       0       0       0
Scripsiella sp.                           0       0       0       0
Flagellata                              22072   203249   4598   22992
Flagellates/Ciliates                      0     46904     0       0
  (< 10 [micro]m)
Flagellates                             22072   156346   4598   22992
  (< 10 [micro]m)

                            Station          7               8

                            Depth (m)     0      50       0      50
Species
Acantharia                                0       0       0      80
Nasselaria                                0       0       0      80
Bacillariophyceae                         0      240    2720    1760
Bacteriastrum sp.                         0       0      320      0
Chaetoceros atlanticus                    0       0       0       0
Chaetoceros peruvianus                    0       0      40       0
Chaetoceros spp.                          0       0      160     40
Cylindrotheca closterium                  0       0      320     160
Dactyliosolen sp.                         0      20      280     200
Nitszchia longissima                      0       0       0       0
Nitszchia spp.                            0       0       0       0
Pennadas indeterminates                   0      20      320     160
Pleurosigma spp.                          0       0       0       0
Pseudonitzschia spp.                      0      160    1040    1200
Rhizosolenia alata                        0       0       0       0
Rhizosolenia bergonii                     0       0       0       0
Rhizosolenia spp.                         0      40      240      0
Thalassiothrix sp.                        0       0       0       0
Cianophyceae                              0       0       0       0
Ciliata                                  300     420     240     960
Acanthostomella                           0       0       0       0
  norvegica ?
Ascampbeliella sp.                        0       0       0       0
Ciliates (> 15 [micro]m)                 280     340     120     600
Ciliates (< 15 [micro]m)                  0       0       0       0
Dictiocysta elegans                       0       0       0       0
Dictiocysta mitra                         0      60       0       0
Dictiocysta sp.                           0       0       0      40
Eutintinnus fraknoi                       0       0       0       0
Eutintinnus lusus-undae                   0      20       0      40
Laboea spp.                               0       0       0       0
Parundela caudata                        20       0      120     80
Protorhabdonella curta                    0       0       0      40
Rhabdonella chilensis                     0       0       0       0
Rhabdonella sp.                           0       0       0      40
Salpinguella sp.                          0       0       0      80
Steentrupiella pozzi                      0       0       0       0
Undella sp.                               0       0       0      40
Undella claparedei                        0       0       0       0
Xystonella treforti                       0       0       0       0
Dictyochophyceae                         20       0      80      80
Dictyocha fibula                          0       0       0       0
Dictyocha sp.                            20       0      80       0
Dictyocha speculum                        0       0       0      80
Dinophyceae                             14495   10756   13616   15215
Ceratium extensum                        40       0       0       0
Ceratium furca                           120     20       0       0
Ceratium fusus                           160     60       0      40
Ceratium tripos                           0       0      40       0
Athecate dinoflagellates                 340     380    1840     560
  (> 15 [micro]m)
Athecate dinoflagellates                13795   10116   11496   14255
  (< 15 [micro]m)
Thecate dinoflagellates                   0       0       0       0
Dinophysis sp.                            0      40       0       0
Dissodinium sp.                           0       0       0       0
Gonyaulax polygramma                      0       0       0       0
Ornithocercus sp.                         0       0      40       0
Oxytosum sp.1                            20      120     120     120
Oxytosum sp.2                            20      20      80       0
Podolampas sp.                            0       0       0       0
Prorocentrum sp.                          0       0       0      40
Protoperidinium conicum                   0       0       0       0
Protoperidinium sp.                       0       0       0      40
Scripsiella sp.                           0       0       0      160
Flagellata                              12876   32189   1839    6898
Flagellates/Ciliates                      0       0       0       0
  (< 10 [micro]m)
Flagellates                             12876   32189   1839    6898
  (< 10 [micro]m)

                            Station     Mean

                            Depth (m)
Species
Acantharia                                7
Nasselaria
Bacillariophyceae                        643
Bacteriastrum sp.
Chaetoceros atlanticus
Chaetoceros peruvianus
Chaetoceros spp.
Cylindrotheca closterium
Dactyliosolen sp.
Nitszchia longissima
Nitszchia spp.
Pennadas indeterminates
Pleurosigma spp.
Pseudonitzschia spp.
Rhizosolenia alata
Rhizosolenia bergonii
Rhizosolenia spp.
Thalassiothrix sp.
Cianophyceae                             205
Ciliata                                  654
Acanthostomella
  norvegica ?
Ascampbeliella sp.
Ciliates (> 15 [micro]m)
Ciliates (< 15 [micro]m)
Dictiocysta elegans
Dictiocysta mitra
Dictiocysta sp.
Eutintinnus fraknoi
Eutintinnus lusus-undae
Laboea spp.
Parundela caudata
Protorhabdonella curta
Rhabdonella chilensis
Rhabdonella sp.
Salpinguella sp.
Steentrupiella pozzi
Undella sp.
Undella claparedei
Xystonella treforti
Dictyochophyceae                         27
Dictyocha fibula
Dictyocha sp.
Dictyocha speculum
Dinophyceae                             9416
Ceratium extensum
Ceratium furca
Ceratium fusus
Ceratium tripos
Athecate dinoflagellates
  (> 15 [micro]m)
Athecate dinoflagellates
  (< 15 [micro]m)
Thecate dinoflagellates
Dinophysis sp.
Dissodinium sp.
Gonyaulax polygramma
Ornithocercus sp.
Oxytosum sp.1
Oxytosum sp.2
Podolampas sp.
Prorocentrum sp.
Protoperidinium conicum
Protoperidinium sp.
Scripsiella sp.
Flagellata                              22839
Flagellates/Ciliates
  (< 10 [micro]m)
Flagellates
  (< 10 [micro]m)

Table 2. Composition and abundance of zooplankton
(ind 1000 [m.sup.-3]) on
the seamounts Juan Fernandez 1 and Juan Fernandez 2. Only the
percentage of each taxonomic group is indicated.

Tabla 2. Composicion y abundancia de zooplancton (ind 1000 [m.sup.-3])
en los montes submarinos Juan Fernandez 1 y Juan Fernandez 2. Se
indica solamente el porcentaje de cada grupo taxonomico.

                                          Station

                         1         2         3         4         5

                                         Stratum (m)

Species               (0-250)   (0-250)   (0-300)   (0-300)   (0-350)

Euphausiacea             2         4        118       35         7
Euphausia gibba          0         0        12         0         0
Euphausia gibboides      0         0        20        11         0
Euphausia mucronata      2         0        47        13         7
Euphausia sp.            0         0        12         0         0
Nematoscelis sp.         0         4        27        11         0
Mysidacea                0         0         0        11        11
Amphipoda               12        49        71        19        22
Vibilia armata          12        41        67        13        11
Acanthoscina             0         4         4         3         7
  acanthodes
Platyscelus sp.          0         4         0         3         4
Ostracoda                0         3        32        52        54
Copepoda                337       864      4338      2490      8917
Acartia sp.              4        33        39        21        254
Haloptilus               0         0         0         0        60
  longicornis
Haloptilus spiniceps     0         0         0         0        30
Haloptilus sp.           4         0         0         0         0
Calanus sp.              0         0         0         0         0
Canthocalanus pauper    24        17        125       118        0
Nannocalanus sp.        20        33         0         0         0
Candacia curta           0         0         8         0         0
Candacia sp.             4        17         0        75        15
Corycaeus sp.            8        17        55         0        30
Eucalanus inermis        0         0         0         0        30
Eucalanus sp.            4        50        16         0         0
Rhincalanus sp.          0         0        424       172       119
Euchaeta sp.             4         0        133       172       45
Heterorhabdus sp.       28        116       55        11        851
Lucicutia sp.            4        17        24        43        30
Pleuromamma sp.         44        17       2031        0       2657
Pleuromamma              4        66         0        976        0
  borealis
Oncaea conifera          8         0        149       86         0
Oncaea sp.               4        17         0         0        149
Oithona sp.              8        17        71        21        149
Pontellina sp.           0         0         0         0         0
Clausocalanus sp.       161       364       643       236      3000
Sapphirina sp.           4        50         0        32        15
Acrocalanus sp.          0         0         0        32         0
Paracalanus sp.          0        33         0        86         0
Euaetideus sp.           0         0         0         0        75
Euchirella sp.           0         0        149       161       478
Gaudius sp.              0         0        165       139       239
Scaphocalanus sp.        0         0        251       97        687
Scolecithrix sp.         0         0         0        12         4
Cirripedia               4         0         0         0         0
Decapoda (larvae)        0         0         0         3         4
Emerita analoga          0         0         0         3         4
Medusae                  0         0         0         3         8
Cunina peregrina         0         0         0         3         0
Obelia spp.              0         0         0         0         4
Rophalonema velatum      0         0         0         0         4
Siphonophorae            6         4        59        59        34
Abylopsis tetragona      0         0        16         5         4
Eudoxoides spiralis      2         0         0         0         0
Dimophyes arctica        0         0         8         3         0
Lensia conoidea          0         0         0         3         7
Lensia hotspur           0         0         0         0         4
Lensia leloupi           0         0         0         0         4
Lensia sp.               0         0         0         0         4
Praya sp.                0         0         0        32         0
Sphaeronectes            2         0        35        16        11
  gracilis
Sulculeolaria chuni      2         0         0         0         0
Sulculeolaria            0         4         0         0         0
  quadrivalvis
Ctenophora               0         8         8         0         0
Beroe cucumis            0         4         0         0         0
Pleurobrachia bachei     0         4         8         0         0
Chaetognatha            88        141       393       249       198
Eukrohnia hamata         8        21        71        32        93
Sagitta decipiens        0         0         0        48         0
Sagitta enflata         30        62        129       113        0
Sagitta hexaptera        8         0        12         0        19
Sagitta minima           0         0        118        5        19
Sagitta tasmanica        0         0         4         8        30
Juvenil individuals     42        58        59        43        37
Salpida                 38        62        537       21        70
Ihlea magalhanica       28        17        110       21        63
Pegea confoederata      10        45        427        0         7
Appendicularia           8         8         4         8        45
Polychaeta               8         0        55        56        56
Nemertina                0         0         0         0         0
Pisces (eggs             0        74         4        42         7
  and larvae)
Hygophum bruuni          0         0         4         8         0
Sardinops sagax          0        74         0        21         7
Myctophidae              0         0         0        13         0
Total                   986      2423      11147     5969      18700
                                 Station

                         6         7         8      Total

                               Stratum (m)

Species               (0-268)   (0-250)   (0-250)

Euphausiacea             9        158        9       342
Euphausia gibba          0         0         0       12
Euphausia gibboides      0        14         0       45
Euphausia mucronata      0        77         9       155
Euphausia sp.            0        24         0       36
Nematoscelis sp.         9        43         0       94
Mysidacea                0         5         0       27
Amphipoda               28        62        77       340
Vibilia armata          23        62        77       306
Acanthoscina             0         0         0       18
  acanthodes
Platyscelus sp.          5         0         0       16
Ostracoda               19         9        12       181
Copepoda               1429      2766      1165     22306
Acartia sp.             28        38         0       417
Haloptilus              37         0         0       97
  longicornis
Haloptilus spiniceps    18         0         0       48
Haloptilus sp.           0         0        17       21
Calanus sp.             65        19        51       135
Canthocalanus pauper     0         0         0       284
Nannocalanus sp.         0         0         0       53
Candacia curta           0         0        26       34
Candacia sp.            18         0         0       129
Corycaeus sp.            0        10         0       120
Eucalanus inermis       28         0         0       58
Eucalanus sp.            9        77        17       173
Rhincalanus sp.          0         0         0       715
Euchaeta sp.             0        29         9       392
Heterorhabdus sp.       65        220       197     1543
Lucicutia sp.           111       134       77       440
Pleuromamma sp.         562      1148       308     6767
Pleuromamma              0         0         0      1046
  borealis
Oncaea conifera          9        19        26       297
Oncaea sp.               0         0         0       170
Oithona sp.             28        115       17       426
Pontellina sp.           0        19         0       19
Clausocalanus sp.       378       766       248     5796
Sapphirina sp.          18        19        120      258
Acrocalanus sp.          0         0         0       32
Paracalanus sp.          0         0         0       119
Euaetideus sp.           0         0         0       75
Euchirella sp.          55        96        43       982
Gaudius sp.              0        57         9       609
Scaphocalanus sp.        0         0         0      1035
Scolecithrix sp.         0         0         0       16
Cirripedia               0         0         0        4
Decapoda (larvae)        0         0         0        7
Emerita analoga          0         0         0        7
Medusae                  5         0         0       16
Cunina peregrina         0         0         0        3
Obelia spp.              0         0         0        4
Rophalonema velatum      5         0         0        9
Siphonophorae           23        101       13       299
Abylopsis tetragona      9         5         0       39
Eudoxoides spiralis      0         0         0        2
Dimophyes arctica        0         0         0       11
Lensia conoidea          0         0         0       10
Lensia hotspur           0         0         0        4
Lensia leloupi           0         5         0        9
Lensia sp.               0         5         4       13
Praya sp.                0         0         0       32
Sphaeronectes           14        86         9       173
  gracilis
Sulculeolaria chuni      0         0         0        2
Sulculeolaria            0         0         0        4
  quadrivalvis
Ctenophora               9         5         9       39
Beroe cucumis            0         0         0        4
Pleurobrachia bachei     9         5         9       35
Chaetognatha            216       153       119     1557
Eukrohnia hamata        37        19        17       298
Sagitta decipiens        0         0         0       48
Sagitta enflata         101       67        77       579
Sagitta hexaptera        0         0         0       39
Sagitta minima           0         5         0       147
Sagitta tasmanica        0         0         4       46
Juvenil individuals     78        62        21       400
Salpida                 18        53        17       816
Ihlea magalhanica        9        53         0       301
Pegea confoederata       9         0        17       515
Appendicularia           9         5         4       91
Polychaeta              23        48         9       255
Nemertina                0         5         0        5
Pisces (eggs             0        24         0       151
  and larvae)
Hygophum bruuni          0        19         0       31
Sardinops sagax          0         0         0       102
Myctophidae              0         5         0       18
Total                  3525      6716      2843     52309

                      Percentage

Species                  (%)

Euphausiacea             1.29
Euphausia gibba
Euphausia gibboides
Euphausia mucronata
Euphausia sp.
Nematoscelis sp.
Mysidacea                0.10
Amphipoda                1.29
Vibilia armata
Acanthoscina
  acanthodes
Platyscelus sp.
Ostracoda                0.68
Copepoda                84.38
Acartia sp.
Haloptilus
  longicornis
Haloptilus spiniceps
Haloptilus sp.
Calanus sp.
Canthocalanus pauper
Nannocalanus sp.
Candacia curta
Candacia sp.
Corycaeus sp.
Eucalanus inermis
Eucalanus sp.
Rhincalanus sp.
Euchaeta sp.
Heterorhabdus sp.
Lucicutia sp.
Pleuromamma sp.
Pleuromamma
  borealis
Oncaea conifera
Oncaea sp.
Oithona sp.
Pontellina sp.
Clausocalanus sp.
Sapphirina sp.
Acrocalanus sp.
Paracalanus sp.
Euaetideus sp.
Euchirella sp.
Gaudius sp.
Scaphocalanus sp.
Scolecithrix sp.
Cirripedia               0.20
Decapoda (larvae)        0.03
Emerita analoga
Medusae                  0.06
Cunina peregrina
Obelia spp.
Rophalonema velatum
Siphonophorae            1.13
Abylopsis tetragona
Eudoxoides spiralis
Dimophyes arctica
Lensia conoidea
Lensia hotspur
Lensia leloupi
Lensia sp.
Praya sp.
Sphaeronectes
  gracilis
Sulculeolaria chuni
Sulculeolaria
  quadrivalvis
Ctenophora               0.15
Beroe cucumis
Pleurobrachia bachei
Chaetognatha             5.89
Eukrohnia hamata
Sagitta decipiens
Sagitta enflata
Sagitta hexaptera
Sagitta minima
Sagitta tasmanica
Juvenil individuals
Salpida                  3.09
Ihlea magalhanica
Pegea confoederata
Appendicularia           0.34
Polychaeta               0.96
Nemertina                0.02
Pisces (eggs             0.57
  and larvae)
Hygophum bruuni
Sardinops sagax
Myctophidae
Total                   100.0

Table 3. Invertebrate species collected with dredging.

Tabla 3. Especies de invertebrados recolectados con rastra.

Phylum/Class/Order   Number of            Phylum/Class/Order
                      samples

Asteroidea              25           Ophiuroidea/Phynophiurida
Decapoda (spp.)          5             Polychaeta/Terebellidae
Gastropoda (spp.)        6       Porifera + Ophiuroidea + Polychaeta
Echinoidea              38             Actiniaria + Polychaeta
Porifera (spp.)         34                   Ophiuroidea
Gorgonia (spp.)          5         Porifera + Bryozoan + Polychaeta
Zoanthidea (spp.)       16             Lophophorates/Bryozoan
Holothuroidea            6           Bivalvia/Paleoheterodonta
Echinoidea/             142              Crustacea/Caridea
  Echinacea (spp.)
Actiniaria              27              Anthozoa/Actiniaria
Polychaeta (spp.)       55             Bivalvia (shell) (spp.)
Echinoidea +             6              Porifera + Polychaeta
  Ophiuroidea
Gorgonia/               10
  Ophioroida

Phylum/Class/Order   Number of
                      samples

Asteroidea               3
Decapoda (spp.)         12
Gastropoda (spp.)        1
Echinoidea               1
Porifera (spp.)          1
Gorgonia (spp.)          1
Zoanthidea (spp.)        1
Holothuroidea            1
Echinoidea/              1
  Echinacea (spp.)
Actiniaria               3
Polychaeta (spp.)        6
Echinoidea +             3
  Ophiuroidea
Gorgonia/
  Ophioroida

Table 4. Name, mean latitude and longitude, and the estimated
area, effort, and relative fishing effect index (FEI) of six
seamounts where extractive activity was conducted between 2000
and 2006.

Tabla 4. Nombre del monte, latitud y longitud media, area estimada,
esfuerzo estimado e indice relativo de pesca (FEI) de seis montes
donde se efectuo actividad extractiva durante 2000-2006.

Seamount       Latitude          Longitude           Area
                 (S)                (W)          ([km.sup.2])

JF1        33[degrees]39.0'   78[degrees]26.4'       608
JF2        33[degrees]33.6'   77[degrees]41.4'       443
JF3        33[degrees]23.4'   77[degrees]25.2'        62
JF4        33[degrees]26.4'   76[degrees]52.8'        91
JF5        33[degrees]43.8'   79[degrees]37.2'        17
JF6        34[degrees]04.8'   80[degrees]15.6'       s/i

Seamount   Effort        FEI
            (km)    ([km.sup.-1])

JF1        1.526        2.51
JF2        4.667        10.54
JF3         395         6.42
JF4         906         11.70
JF5          50         1.52
JF6         s/i          s/i
COPYRIGHT 2009 Pontificia Universidad Catolica de Valparaiso, Escuela de Ciencias del Mar
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Author:Yanez, Eleuterio; Silva, Claudio; Vega, Rodrigo; Espindola, Fernando; Alvarez, Lorena; Silva, Nelson
Publication:Latin American Journal of Aquatic Research
Date:Nov 1, 2009
Words:8064
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