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1. The influence of age and cohort on the distribution of walleye pollock (Gadus chalcogrammus) in the eastern Bering Sea

Author

Stevenson, Duane E., Kotwicki, Stan, Thorson, James T., Correa, Giancarlo M., and Buckley, Troy

Subjects
Walleye (Fish) -- Distribution -- Behavior -- Physiological aspects, Company distribution practices, Earth sciences
Abstract

The spatial distributions of marine fish populations are influenced by environmental conditions, intrinsic properties of the populations, and prior distribution. The influence of these factors may not be consistent across age classes. For this study, age composition estimates for walleye pollock (Gadus chalcogrammus) collected on bottom-trawl surveys in the Bering Sea were used to estimate range correlation indices, population centers of gravity, and effective area occupied. Age- specific density maps suggested a circular ontogenic migration during the summer feeding season, with the youngest and oldest groups most broadly distributed. Range correlation analysis among age groups and year classes provided clear evidence of a population cohort effect in the spatial distribution of the population. Variance decomposition analysis indicated that the variance in the spatial distribution of age groups during summer was influenced by the initial distribution of that cohort as recruits. Model-based analyses showed that extrinsic temperature variables affected the youngest and oldest age classes the most, but provided no indication of age-related effects for intrinsic population factors. This study showed that both cohort and age-specific factors are important drivers of spatial distribution. Key words: demographics, age composition, distribution, walleye pollock, modeling, VAST La repartition spatiale de populations de poissons marins est influencee par les conditions ambiantes, des proprietes intrinseques des populations et la repartition prealable. L'influence de ces facteurs pourrait ne pas etre uniforme d'une classe d'age a l'autre. Nous avons utilise des estimations de la composition par age pour des goberges de l'Alaska (Gadus chalcogrammus) prelevees dans le cadre d'evaluations au chalut de fond dans la mer de Behring pour estimer des indices de correlation des aires de repartition, les centres de gravite de la population et la superficie occupee effective. Des cartes de densite selon l'age indiqueraient une migration ontogenetique circulaire durant la saison d'alimentation estivale, les groupes les plus jeunes et les plus vieux presentant les repartitions les plus vastes. L'analyse de correlation des aires de repartition de differents groupes d'age et classes d'annee fournit des preuves claires d'un effet populationnel de la cohorte dans la repartition spatiale de la population. L'analyse de decomposition de la variance indique que la variance de la repartition spatiale des groupes d'age durant l'ete est influencee par la repartition initiale de la cohorte au moment du recrutement. Des analyses reposant sur des modeles montrent que des variables extrinseques associees a la temperature exercent la plus grande influence sur les classes d'age les plus jeunes et les plus vieilles, mais elles ne revelent aucun effet relie a l'age de facteurs intrinseques a la population. L'etude demontre que des facteurs associes tant a la cohorte qu'a l'age exercent une importante influence sur la repartition spatiale. [Traduit par la Redaction] Mots-cles : demographie, composition par age, repartition, goberge de l'Alaska, modelisation, VAST, Introduction The spatial distributions of fish populations are influenced by many factors. Environmental variables that define habitat suitability are clearly important. For example, physiological tolerances and resource availability directly affect [...]

Published
2022
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15. Biodiversity and Biogeography of the Islands of the Kuril Archipelago

Author

Pietsch, Theodore W., Bogatov, Victor V., Amaoka, Kunio, Zhuravlev, Yuri N., Barkalov, Vyacheslav Y., Gage, Sarah, Takahashi, Hideki, Lelej, Arkady S., Storozhenko, Sergey Y., Minakawa, Norobu, Bennett, Daniel J., Anderson, Trevor R., Ôhara, Masahiro, Prozorova, Larisa A., Kuwahara, Yasuhiro, Kholin, Sergey K., Yabe, Mamoru, Stevenson, Duane E., and MacDonald, Erin L.

Published
2003

17. Interactions between fisheries and early life stages of skates in nursery areas of the eastern Bering Sea

Author

Stevenson, Duane E., Hoff, Gerald R., Orr, James W., Spies, Ingrid, and Rooper, Christopher N.

Subjects
Fisheries -- Environmental aspects, Skates (Fishes) -- Environmental aspects, Fishes, Eggs (Food), Longlining (Fisheries), Zoology and wildlife conservation
Abstract

Abstract--From late 2014 through 2017, fishery observers in the North Pacific Observer Program, National Marine Fisheries Service, were trained in the identification and sampling of skate egg cases to investigate [...]

Published
2019
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28. Interspecific differences in the flow regimes and drag of North Pacific skate egg cases

Author

Hall, Kayla C., Elcock, Jaida N., Hoff, Gerald R., Stevenson, Duane E., Summers, Adam P., Donatelli, Cassandra M., Hall, Kayla C., Elcock, Jaida N., Hoff, Gerald R., Stevenson, Duane E., Summers, Adam P., and Donatelli, Cassandra M.

Abstract

Author Posting. © The Author(s), 2022. This is the author's version of the work. It is posted here by permission of Oxford University Press for personal use, not for redistribution. The definitive version was published in Integrative & Comparative Biology 62(3), (2022): 805-816, https://doi.org/10.1093/icb/icac108., Skates are a diverse group of dorso-ventrally compressed cartilaginous fish found primarily in high-latitude seas. These slow-growing oviparous fish deposit their fertilized eggs into cases, which then rest on the seafloor. Developing skates remain in their cases for 1–4 years after they are deposited, meaning the abiotic characteristics of the deposition sites, such as current and substrate type, must interact with the capsule in a way to promote long residency. Egg cases are morphologically variable and can be identified to species. Both the gross morphology and the microstructures of the egg case interact with substrate to determine how well a case stays in place on a current-swept seafloor. Our study investigated the egg case hydrodynamics of eight North Pacific skate species to understand how their morphology affects their ability to stay in place. We used a flume to measure maximum current velocity, or “break-away velocity,” each egg case could withstand before being swept off the substrate and a tilt table to measure the coefficient of static friction between each case and the substrate. We also used the programing software R to calculate theoretical drag on the egg cases of each species. For all flume trials, we found the morphology of egg cases and their orientation to flow to be significantly correlated with break-away velocity. In certain species, the morphology of the egg case was correlated with flow rate required to dislodge a case from the substrate in addition to the drag experienced in both the theoretical and flume experiments. These results effectively measure how well the egg cases of different species remain stationary in a similar habitat. Parsing out attachment biases and discrepancies in flow regimes of egg cases allows us to identify where we are likely to find other elusive species nursery sites. These results will aid predictive models for locating new nursery habitats and protective policies for avoiding the destruction of these nursery s, This work was supported by the NSF-REU and FHL Blinks-Beacon for funding JNE. And the Stephen and Ruth Wainwright Endowed Fellowship, BEACON and Hoag Awards, Robert T. Paine Experimental and Field Ecology Award, FHL Award, FHL Marine Science Fund, FHL Student Fund (Kohn), Patricia L. Dudley Endowment for funding KCH., 2023-07-04

Published
2022

32. Observer-reported skate bycatch in the commercial groundfish fisheries of Alaska

Author

Stevenson, Duane E. and Lewis, Kristy A.

Subjects
Skates (Fishes) -- Methods, Rajiformes -- Methods, Longlining (Fisheries) -- Methods, Fishery management -- Methods, Bycatch -- Control -- Methods
Abstract

Abstract--We analyzed skate catch data collected by observers in the North Pacific Groundfish Observer Program (NPGOP) from 1998 through 2008 to document recent changes in the identification of skates by [...]

Published
2010

34. Emerging patterns of species richness, diversity, population density, and distribution in the skates (Rajidae) of Alaska

Author

Stevenson, Duane E., Orr, James W., Hoff, Gerald R., and McEachran, John D.

Subjects
Skates (Fishes) -- Comparative analysis -- Distribution -- Research, Fish populations -- Comparative analysis -- Distribution -- Research, Rajiformes -- Comparative analysis -- Distribution -- Research, Population density -- Research -- Comparative analysis, Zoology and wildlife conservation, Company distribution practices, Distribution, Research, Comparative analysis
Abstract

Abstract--Six years of bottom-trawl survey data, including over 6000 trawls covering over 200 [km.sup.2] of bottom area throughout Alaska's subarctic marine waters, were analyzed for patterns in species richness, diversity, [...]

Published
2008

38. Molecular phylogenetics of snailfishes (Cottoidei: Liparidae) based on MtDNA and RADseq genomic analyses, with comments on selected morphological characters

Author

Orr, James Wilder, Spies, Ingrid, Stevenson, Duane E., Longo, Gary C., Kai, Yoshiaki, Ghods, Sam, and Hollowed, Myles

Subjects
Biodiversity, Taxonomy
Abstract

Orr, James Wilder, Spies, Ingrid, Stevenson, Duane E., Longo, Gary C., Kai, Yoshiaki, Ghods, Sam, Hollowed, Myles (2019): Molecular phylogenetics of snailfishes (Cottoidei: Liparidae) based on MtDNA and RADseq genomic analyses, with comments on selected morphological characters. Zootaxa 4642 (1): 1-79, DOI: https://doi.org/10.11646/zootaxa.4642.1.1

Published
2019

42. Eumicrotremus gyrinops Garman 1892

Author

Stevenson, Duane E., Mecklenburg, Catherine W., and Kai, Yoshiaki

Subjects
Scorpaeniformes, Actinopterygii, Cyclopteridae, Eumicrotremus, Animalia, Eumicrotremus gyrinops, Biodiversity, Chordata, Taxonomy
Abstract

Eumicrotremus gyrinops (Garman 1892) Alaskan Lumpsucker Figs. 3, 5; Table 1 Cyclopteroides gyrinops Garman 1892:37. [Type locality: St. Paul Island, Alaska. Holotype: MCZ 16026.] Lethotremus muticus Gilbert 1896:449. [Type locality: Albatross station 2844, near Unimak Pass, 54 fathoms. Lectotype: USNM 53806; Paralectotypes: CAS-SU 774, CAS-SU 3093, USNM 48614, USNM 59376.] Eumicrotremus phrynoides Gilbert & Burke 1912:69. [Type locality: Albatross station 4779, Petrel Bank, Bering Sea, 54���56 fathoms. Holotype: USNM 74378.] Cyclopteropsis phrynoides: Soldatov & Lindberg 1930:325. [New combination]. Cyclopterocottus phrynoides: Popov 1930:74. [New combination]. Eumicrotremus gyrinops: Lindberg & Legeza, 1955:423. [New combination]. Eumicrotremus muticus: Oku et al., 2017:55. [New combination]. Holotype. MCZ 16026, 38.5 mm, St. Paul Island, Alaska, 56.9��N, 170.4��W. Diagnosis. A species of Eumicrotremus distinguished from all other ENP species of Eumicrotremus by the following combination of characters: tubercles, when present, irregularly arranged in interorbital space (vs. four distinct interorbital rows in E. orbis); enlarged pair of tubercles absent at origin of second dorsal and anal fin (vs. present in E. andriashevi); thick dermal papillae absent (present in E. barbatus). Eumicrotremus gyrinops is distinguished from members of the WNP E. asperrimus species complex (including E. asperrimus, Cyclopteropsis bergi, and C. lindbergi) by higher modal counts of dorsal-fin spines (usually VII vs. usually VI) and lower modal counts of pectoral-fin rays (24���28 vs. 25���30). Counts and proportions. First dorsal-fin spines VI���VIII; second dorsal-fin rays 10���12 (10.6); anal-fin rays 9��� 12 (10.1); pectoral-fin rays 24���28 (26.1); vertebrae 10���12 + 15���19 = 26���30 (27.9). Following proportions as percent SL: head length 28.9���45.1 (36.9); body depth 28.7���57.7 (45.6); first dorsal-fin base 16.1���29.9 (23.5); second dorsal-fin base 15.4���26.2 (21.5); anal-fin base 13.7���25.4 (18.0); pectoral-fin base 24.8���35.8 (29.3); interdorsal distance 2.1���7���19.7 (7.9); predorsal length 29.1���47.2 (38.9); snout to vent 57.3���76.6 (64.6); vent to anal-fin origin 9.7���23.6 (16.3); caudal peduncle length 8.5���14.7 (11.6); caudal peduncle depth 8.0���13.0 (9.9); pectoral-fin length 15.6���26.8 (21.3); snout to disc 17.5���35.1 (24.4); disc length (outer) 20.2���30.3 (23.7); disc length (inner) 9.9���16.2 (12.1); disc width (outer) 18.5���29.3 (24.1); disc width (inner) 9.7���17.0 (13.3); disc to vent (outer) 8.5���31.1 (21.1); disc to vent (inner) 11.6���35.6 (25.6); caudal-fin length 22.5���31.9 (26.7). Following proportions as percent HL: orbit length 31.5���50.8 (40.4); snout length 7.4���25 (15.9); postorbital head length 32.7��� 54.1 (41.2); interorbital width 40.9���78.5 (55.4); mouth width 50.4���93.9 (73.2); anterior internasal width 20.4���36.1 (28.9). Description. Head and body short, firm, and globose; snout short; cheeks tumid. Interorbital space broad, slightly concave. Eye large, placed high on head, entering dorsal profile. Nostrils with tubes, the anterior short and wide, posterior relatively narrow, approximately same length as anterior. Mouth wide, slightly oblique, posterior margin of maxilla terminating anterior to margin of orbit. Teeth in jaws blunt, conical, arranged in three to five distinct diagonal rows on both premaxilla and dentary, approximately 25���35 teeth in each jaw. Upper and lower pharyngeal teeth present, similar in size and shape to jaw teeth. Cephalic sensory system consisting of supraorbital, interorbital, postorbital, suborbital, and operculomandibular canals. Supraorbital canal opening through two pores, one anterior to nostrils and one medial to internarial space. Interorbital canal opening through single median pore. Postorbital canal opening anteriorly through a supraorbital pore and posteriorly through a postbranchial pore. Suborbital canal with two pores, anteriormost pore ventral to orbit, posterior pore posteroventral to orbit. Operculomandibular canal with single opercular pore on cheek and four mandibular pores closely spaced along lower jaw. All sensory pores opening through short thick tubes. Development and distribution of bony tubercles on head and body highly variable. In holotype (38.5 mm SL), tubercles small, low, rounded, embedded in skin, each with several prominent spines; tubercles few and sparsely spaced, forming an indistinct row on either side of spinous dorsal fin, several additional tubercles dispersed along anterior portion of body; head naked. Tubercles generally smaller and fewer in smaller specimens and in males; larger males (45���55 mm SL) with tubercles completely covered by skin, producing wart-like protrusions on body; males and smaller females often without tubercles on head or body; all specimens examined over 58 mm SL (n = 13) completely covered with large tubercles, and all female. First dorsal fin high, usually not covered with thick skin or tubercles in smaller specimens (including holotype); becoming increasingly embedded in skin and covered with spiny tubercles in larger specimens, particularly in females; fin membranes moderately to heavily pigmented. Second dorsal and anal fins directly opposite each other, nearly equal in length and height, usually without bony tubercles or fleshy papillae; fin membranes translucent, without pigment. Caudal fin truncate; fin membranes translucent, without pigment; rays in some specimens with several faint dark blotches suggesting bands running perpendicular to body axis. Pectoral fins translucent, their bases densely covered with small melanophores; larger specimens usually with several rounded tubercles covering pectoral base. Pelvic disc large, ovate, slightly constricted anteriorly; its length usually slightly greater than its width. Anus approximately midway between posterior margin of pelvic disc and origin of anal fin. Coloration. Holotype with small melanophores relatively evenly spaced over entire head and body, without conspicuous bands, stripes, or blotches. Additional material in life yellowish-brown to medium brown, generally darker on head and dorsum, often with dark brown to black blotches and vermiculations, particularly on dorsal surface of head and body; becoming lighter posteriorly and generally white or nearly white on ventral surface. Some degree of faint banding usually present on pectoral and all median fins. Distribution. Specimens examined are from the eastern Bering Sea, Aleutian Islands, and western and central Gulf of Alaska (Fig. 6). Remarks. The holotype of E. gyrinops (MCZ 16026) is in poor condition. It has apparently been desiccated and rehydrated at least once. Thus, the tubes associated with the mandibular pores, and to a lesser extent the other pores as well, appear longer and more prominent than in most other specimens. In addition, its fins are badly damaged, and its internal organs have been removed through a very large incision on the left side of the body. Material examined. Eumicrotremus asperrimus (18 specimens): Sea of Japan: FAKU 131263 (GenBank AB 917623, 917693), 102 mm female, Kyoto, 36��N, 134.75��E, 320 m; FAKU 131983 (GenBank AB917614, 917684), 40 mm male, 35.881��N, 132.474��E, 240 m; FAKU 132544 (GenBank AB917600, 917670), 59 mm male, 37.758��N, 136.294��E, 342 m; FAKU 132564 (GenBank AB917601, 917671), 58 mm male, 38.026��N, 136.916��E, 330 m; FAKU 132598 (GenBank AB917621, 917691), 34 mm male, Ishikawa, 37.7��N, 136.308��E, 260 m; FAKU 133204 (GenBank AB 917615, 917685), 61 mm male, Kyoto, 38.03��N, 135.413��E, 300 m. Sea of Okhotsk: FAKU 133231 (GenBank AB917616, 917686), 98 mm female, 45.062��N, 143.068��E; FAKU 133235 (GenBank AB917620, 917690), 52 mm, 44.99��N, 144.115��E, 220 m; FAKU 133279 (GenBank AB917604, 917674), 56 mm female, 44.382��N, 144.341��E, 350 m; FAKU 133280 (GenBank AB917605, 917675), 54 mm female, 44.382��N, 144.341��E, 350 m; FAKU 133281 (GenBank AB917606, 917676), 59 mm female, 44.382��N, 144.342��E; FAKU 133282 (GenBank AB917607, 917677), 60 mm male, 44.382��N, 144.342��E; FAKU 133283 (GenBank AB917608, 917678), 60 mm female, 44.382��N, 144.342��E; FAKU 133284 (GenBank AB917609, 917679), 49 mm male, 44.382��N, 144.341��E, 350 m; FAKU 133285 (GenBank AB917610, 917680), 91 mm female, 44.382��N, 144.342��E; FAKU 133286 (GenBank AB917611, 917681), 56 mm female, 44.382��N, 144.341��E, 350 m; FAKU 134958 (GenBank AB917639, 917709), 59 mm female, 44.78��N, 143.928��E, 170 m; FAKU 134985 (GenBank AB917643, 917713), 56 mm male, 45.46��N, 142.967��E, 117 m. Eumicrotremus awae: FAKU 134183, 18 mm, Japan, Sagami Bay; FAKU 134725, 18 mm, Japan, Sagami Bay; FAKU 135824, 24 mm, Japan, Sagami Bay; UW 42938, 16 mm, Japan, Sagami Bay, 35.15��N, 139.17��E. Eumicrotremus bergi (2 specimens): FAKU 132552 (GenBank AB917597, 917667), 59 mm male, Sea of Japan, 38.031��N, 136.778��E, 419 m; FAKU 132557 (GenBank AB917596, 917666), 62 mm male, Sea of Japan, 37.959��N, 137.31��E, 320 m. Eumicrotremus gyrinops (235 specimens): Type material: MCZ 16026, holotype of Cyclopteroides gyrinops, 38.5 mm, St. Paul Island, Alaska; USNM 74378, holotype of Eumicrotremus phrynoides, Albatross station 4779, Petrel Bank, Bering Sea, 54���56 fm; USNM 53806, lectotype of Lethotremus muticus, Albatross station 2844, near Unimak Pass, 54 fm; CAS-SU 774, paralectotype of Lethotremus muticus, Albatross station 2844, near Unimak Pass, 54 fm; CAS-SU 3093, USNM 48614, USNM 59376, paralectotypes of Lethotremus muticus, Albatross station 3223, Unimak Pass, 39 fm. Bering Sea (31 specimens): UW 28373, 85 mm female, 57��0'N, 171��25.02'W, 59 fm; UW 28384, 69 mm female, 60��59.1'N, 177��19.02'W, 130 m; UW 28390, 65 mm female, 60��28.14'N, 177��W, 143 m; UW 119071, 16(29���47 mm males, 27���40 mm females), 56��53'N, 169��39'W, 75 m; UW 119538 (GenBank AB917661, 917731), 92 mm female, 57��59.23'N, 170��20.09'W, 74 m; UW 150056, 82 mm female, 59��19.98'N, 172��28.26'W, 87 m; UW 150057, 51 mm male, 56��50.08'N, 170��26.76'W, 98 m; UW 150071 (GenBank AB917626, 917696), 75 mm female, 54��50.25'N, 169��57.12'W, 71 m; UW 150072, 88 mm female, 60��20.28'N, 174��3.36'W, 90 m; UW 151282, 3(41 mm male, 33���77 mm females), 56��49.57'N, 170��28.07'W, 101 m; UW 151285, 80 mm female, 58��20.58'N, 170��22.32'W, 74 m; UW 151415, 46 mm male, 56��40.32'N, 170��4.44'W, 95 m; UW 152368, 36 mm male, 60��8.88'N, 172��57.12'W, 59 m; UW 155892, 81 mm female, 56��35.22'N, 170��38.22'W, 108 m. Aleutian Islands (160 specimens): UW 22199, 69 mm, 53��43.98'N, 164��49.98'W, 209 m; UW 28389, 42 mm, 54��24'N, 165��24'W; UW 46659, 32 mm, 51��54.6'N, 176��52.2'W, 211 m; UW 46660, 45 mm, 52��51.53'N, 172��27.52'E, 146 m; UW 46662, 45 mm, 53��1.68'N, 173��12.36'E, 133 m; UW 46664, 5(43���51 mm females), 52��11.04'N, 179��39.84'W, 115 m; UW 46665, 5(44���49 mm females), 51��58.98'N, 179��23.52'E, 139 m; UW 49401, 2(40 mm male, 45 mm female), 52��7.8'N, 179��54.6'W, 112 m; UW 49409, 41 mm male, 52��4.92'N, 179��21.54'E, 306 m; UW 49412, 45 mm male, 52��25.86'N, 179��56.52'E, 163 m; UW 49418, 49 mm male, 52��31.27'N, 174��26.96'E, 182 m; UW 49423, 50 mm female, 52��2.82'N, 179��25.26'E, 143 m; UW 49436 (GenBank AB917625, 917629, 917695, 917699), 2(36���38 mm, males), 52��08.14'N, 179��53.41'W, 121 m; UW 49467, 34 mm male, 52��29.96'N, 170��40.65'W, 208 m; UW 49470, 4(37���52 mm females, 36 mm male), 52��10.86'N, 179��37.02'E, 124 m; UW 49471, 4(41���44 mm males), 52��22.62'N, 179��38.82'E, 245 m; UW 49474, 18(34���38 mm males, 30���40 mm females), 51��39.23'N, 176��22.56'W, 143 m; UW 49504, 61 mm female, 52��2.34'N, 179��24.96'E, 145 m; UW 49577, 5(40���42 mm females), 52��59.42'N, 172��21.95'E, 146 m; UW 49580, 49 mm female, 52��28.15'N, 173��11.34'E, 116 m; UW 49587, 45 mm female, 52��35.6'N, 172��55.38'E, 154 m; UW 111260, 39 mm male, 52��27.91'N, 174��12.6'E, 110 m; UW 111265, 35 mm female, 52��23.82'N, 173��58.72'E, 112 m; UW 111267, 2(34��� 41 mm females), 51��39.23'N, 176��22.2'W, 145 m; UW 111280, 52 mm female, 52��52.7'N, 175��12.5'W, 151 m; UW 111288, 62 mm female, 52��25.27'N, 170��16.74'W, 211 m; UW 111300, 47 mm female, 52��21.71'N, 171��16.14'W, 134 m; UW 111309, 40 mm male, 52��21.96'N, 179��54.84'W, 168 m; UW 111310, 35 mm female, 52��29.56'N, 174��22.08'W, 177 m; UW 111311, 7(32���42 mm males, 38���51 mm females), 52��57.72'N, 170��23.82'W, 221 m; UW 111314, 2(49���50 mm females), 52��18.38'N, 175��48.91'E, 235 m; UW 111335, 35 mm male, 52��30.19'N, 174��15.22'W, 102 m; UW 111451, 2(36���44 mm males), 52��29.46'N, 170��8.82'W, 183 m; UW 112040, 35 mm male, 52��22.97'N, 174��8.62'E, 148 m; UW 112041, 41 mm female, 52��26.26'N, 174��17.57'E, 220 m; UW 112272 (GenBank AB917663, 917664, 917733, 917734), 2(32 mm male, 45 mm female), 52��31.20'N, 170��39.25'W, 124 m; UW 117593, 43 mm female, 52��39.45'N, 173��50.48'E, 79 m; UW 151458, 3(35���38 mm males, 33 mm female), 51��2.50'N, 172��15.1'W, 162 m; UW 151803 (GenBank AB917644, 917714), 36 mm male, 51��53.15'N, 173��55.29'W, 136 m; UW 151804 (GenBank AB917645, 917715), 45 mm female, 52��02.56'N, 179��48.44'W, 250 m; UW 151810 (GenBank AB917646, 917716), 43 mm female, 52��49.40'N, 173��41.17'W, 109 m; UW 151811 (GenBank AB917647, 917717), 44 mm female, 52��24.33'N, 170��16.57'W, 213 m; UW 151814 (GenBank AB917648, 917718), 46 mm male, 52��49.42'N, 170��27.32'W, 99 m; UW 152131 (GenBank LC209624, 209640), 49 mm female, 52��35.48'N, 172��55.48'E, 145 m; UW 152132 (GenBank LC209625, 209641), 40 mm male, 52��28.32'N, 173��11.4'E; UW 152138, 2(31 mm male, 33 mm female), 54��22.2'N, 165��32.94'W, 83 m; UW 152355, 3(39���60 mm male, 41 mm female), 52��55.94'N, 170��24.61'W, 222 m; UW 152358 (GenBank LC209626, 209642), 35 mm female, 51��45.04'N, 177��51.7'E, 157 m; UW 152359 (GenBank LC209627, 209643), 3(38 mm male, 37���41 mm females), 51��54.64'N, 173��47.03'W, 118 m; UW 152360 (GenBank LC209628, 209644), 33 mm male, 51��39.08'N, 178��20.06'E, 206 m; UW 152361, 4(36���42 mm males, 33 mm female), 52��29.62'N, 170��23.63'W, 216 m; UW 152362 (GenBank LC209629, 209645), 32 mm male, 52��2.16'N, 179��24.84'E, 150 m; UW 152363 (GenBank LC209630, 209646), 29 mm female, 51��36.96'N, 178��11.28'W, 134 m; UW 152364, 38 mm female, 52��17.28'N, 170��47.58'W, 226 m; UW 152365 (GenBank LC209631, 209647), 35 mm male, 52��49.68'N, 173��41.28'E, 115 m; UW 152366 (GenBank LC209632, 209648), 36 mm male, 51��52.92'N, 173��55.38'W; UW 152367 (GenBank LC209633, 209634, 209649, 209650), 2(37���41 mm males), 52��52.02'N, 171��18.06'W, 204 m; UW 152369 (GenBank LC209635, 209651), 33 mm female, 51��47.28'N, 177��43.56'E, 155 m; UW 152370 (GenBank LC209636, 209652), 3(40���41 mm females), 51��37.98'N, 177��9.96'W, 172 m; UW 152371 (GenBank LC209637, 209653), 2(35���37 mm males), 52��26.88'N, 174��18.66'E, 228 m; UW 152428, 53 mm female, 52��52.28'N, 171��19.06'W, 202 m; UW 152431 (LC209833, 209845), 40 mm female, 52��22.92'N, 174��8.46'E, 155 m; UW 152432, 43 mm female, 52��26.88'N, 174��18.66'E, 228 m; UW 152433 (GenBank LC209638, 209639, 209654, 209655), 2(35���42 mm males), 52��58.62'N, 170��3.72'W, 122 m; UW 152434 (LC209834, 209846), 41 mm male, 52��28.33'N, 173��11.37'E; UW 152438, 2(27���43 mm males), 52��28.59'N, 170��8.7'W, 183 m; UW 152444, 39 mm male, 54��20.65'N, 165��32.94'W, 104 m; UW 152460, 2(38 mm male, 31 mm female), 52��23.18'N, 174��W, 85 m; UW 152466, 2(36 mm male, 46 mm female), 52��48.65'N, 171��31.38'W, 201 m; UW 152469 (LC209835���209843, 209847���209855), 9(37���48 mm females), 52��48.95'N, 173��44.35'E, 111 m; UW 152490 (LC209844, 209856), 42 mm female, 52��24.22'N, 174��15.53'E, 255 m; UW 154964, 9(41 mm male, 36���57 mm females), 52��10.84'N, 179��36.97'E, 127 m; UW 156510, 4(32���38 mm females), 51��47.46'N, 177��40.74'E, 171 m; UW 156512, 37 mm female, 52��28.5'N, 170��44.94'W, 260 m; UW 156511, 2(41���42 mm females), 52��35.28'N, 172��55.72'E, 127 m. Gulf of Alaska (42 specimens): UW 28386, 2(52���54 mm), 56��N, 157��W, 50 fm; UW 47916, 38 mm female, 58��7.47'N, 151��30.6'W, 157 m; UW 47923, 9(34���39 mm females, 37 mm male), 58��56.46'N, 150��19.02'W, 146 m; UW 47935, 2(39 mm female, 39 mm male), 56��43'N, 152��36.72'W, 97 m; UW 47948, 3(32 mm female, 37���40 mm males), 54��53.85'N, 158��42.48'W, 98 m; UW 116417, 40 mm female, 58��46.32'N, 150��23.58'W, 151 m; UW 117047, 4(34���38 mm males, 36���38 mm females), 54��44.1'N, 158��37.26'W, 104 m; UW 117609 (GenBank AB917634, 917704), 3(41���43 mm females, 38 mm male), 58��15.17'N, 151��24.51'W, 157 m; UW 119222 (GenBank AB917627, 917628, 917697, 917698), 2(32���38 mm females), 57��36.33'N, 150��20.16'W, 130 m; UW 119548, 39 mm male, 55��16.88'N, 157��6.48'W, 94 m; UW 119596, 40 mm male, 57��53.28'N, 150��16.47'W, 158 m; UW 119690, 4(38���41 mm females), 58��53.03'N, 150��52.08'W, 164 m; UW 119706, 60 mm female, 58��54.29'N, 150��36.3'W, 119 m; UW 119779 (GenBank AB917631, 917701), 35 mm male, 58��38.59'N, 150��08.45'W, 121 m; UW 119782 (GenBank AB917632, 917702), 39 mm male, 58��30.48'N, 150��17.52'W, 90 m; UW 151260 (GenBank AB917657, 917658, 917659, 917727, 917728, 917729), 5(31���37 mm males, 35 mm female), 58��54'N, 151��24.96'W, 153 m; UW 154590, 39 mm male, 55��29.21'N, 157��2.82'W, 90 m. Eumicrotremus lindbergi (4 specimens): FAKU 132535 (GenBank AB917599, 917669), 55 mm male, Sea of Japan, 36.845��N, 136.317��E, 261 m; FAKU 132563 (GenBank AB917598, 917668), 59 mm male, Sea of Japan, 38.026��N, 136.916��E, 330 m; FAKU 134222 (GenBank AB917624, 917694), 53 mm male, Sea of Japan, Shimane, west of Oki I.; FAKU 134862 (GenBank AB917638, 917708), 54 mm male, Sea of Japan, Shimane, 35.6��N, 131.033��E, 180 m. Eumicrotremus orbis: UW 119821 (GenBank AB917655, 917725), 2(17 mm male, 31 mm female), Salish Sea, San Juan Island, Jackson Beach, 48��31.2'N, 123��W, 2 m., Published as part of Stevenson, Duane E., Mecklenburg, Catherine W. & Kai, Yoshiaki, 2017, Taxonomic clarification of the Eumicrotremus asperrimus species complex (Teleostei: Cyclopteridae) in the eastern North Pacific, pp. 419-435 in Zootaxa 4294 (4) on pages 430-434, DOI: 10.11646/zootaxa.4294.4.2, http://zenodo.org/record/832797, {"references":["Garman, S. (1892) The Discoboli: Cyclopteridae, Liparopsidae, and Liparididae. Memoirs of the Museum of Comparative Zoology, 14 (2), 1 - 96.","Gilbert, C. H. (1896) The ichthyological collections of the steamer Albatross during the years 1890 and 1891. U. S. Commission of Fish and Fisheries, Report of the Commissioner, 19, 393 - 476.","Gilbert, C. H. & Burke, C. V. (1912) Fishes from Bering Sea and Kamchatka. Bulletin of the Bureau of Fisheries, 30, 31 - 96.","Soldatov, V. K. & Lindberg, G. U. (1930) A review of the fishes of the seas of the Far East. Izvestia Tikhookeanskogo Nauchno- Issledovatelskogo Instituta Rybnogo Khozyaystva y Okeanografii, 5, 1 - 576.","Popov, A. M. (1930) A short review of the fishes of the family Cyclopteridae. Annals and Magazine of Natural History, 6, 69 - 76.","Lindberg, G. U. & Legeza, M. I. (1955) Review of the genera and species of the subfamily Cyclopterinae (Pisces). Trudy Zoologicheskogo Instituta Akademii Nauk SSSR, 18, 389 - 458. [in Russian. English translation by Israel Program for Scientific Translations, 1964]","Oku, K., Imamura, H. & Yabe, M. (2017) Phylogenetic relationships and a new classification of the family Cyclopteridae (Perciformes: Cottoidei). Zootaxa, 4221, 1 - 59."]}

Published
2017
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43. Genetic evidence of a northward range expansion in the eastern Bering Sea stock of Pacific cod.

Author

Spies, Ingrid, Gruenthal, Kristen M., Drinan, Daniel P., Hollowed, Anne B., Stevenson, Duane E., Tarpey, Carolyn M., and Hauser, Lorenz

Subjects
SINGLE nucleotide polymorphisms, GEOGRAPHICAL distribution of fishes, CLIMATE change, SEAS
Abstract

Poleward species range shifts have been predicted to result from climate change, and many observations have confirmed such movement. Poleward shifts may represent a homogeneous shift in distribution, seasonal northward movement of specific populations, or colonization processes at the poleward edge of the distribution. The ecosystem of the Bering Sea has been changing along with the climate, moving from an arctic to a subarctic system. Several fish species have been observed farther north than previously reported and in increasing abundances. We examined one of these fish species, Pacific cod, in the northern Bering Sea (NBS) to assess whether they migrated from another stock in the eastern Bering Sea (EBS), Gulf of Alaska, or Aleutian Islands, or whether they represent a separate population. Genetic analyses using 3,599 single nucleotide polymorphism markers indicated that nonspawning cod collected in August 2017 in the NBS were similar to spawning stocks of cod in the EBS. This result suggests escalating northward movement of the large EBS stock during summer months. Whether the cod observed in the NBS migrate south during winter to spawn or remain in the NBS as a sink population is unknown. [ABSTRACT FROM AUTHOR]

Published
2020
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49. Estimating confidence in trawl efficiency and catch quantification for the eastern Bering Sea Shelf survey

Author

Stevenson, Duane E., 1970, Weinberg, Kenneth L., and Lauth, Robert Russell

Subjects
Trawls and trawling--Catch effort--Estimates--Bering Sea--Evaluation
Abstract

The Alaska Fisheries Science Center’s Resource Assessment and Conservation Engineering (RACE) Division has been conducting annual multispecies bottom trawl surveys of the eastern Bering Sea continental shelf using the same standardized gear and trawling procedures since 1982. The data and results from these surveys are available to the general public. However, because the use of these data and results by researchers outside RACE is not monitored, users should be aware of the limitations of this information and design their analyses accordingly. In particular, there are multiple sources of variability in the sampling efficiency of the trawl gear used for the survey, both species- and size-specific, that may affect inferences about the nature of the overall catches and relative animal densities. Furthermore, the quality and specificity of catch quantification (weighing and counting) at sea of many taxa can vary depending on the overall size of the catch and the species composition of the sample, particularly for non-commercial taxa of small size. This document is an assessment of the relative reliability of survey catch weights, numbers, and catch per unit effort estimates derived from the eastern Bering Sea shelf bottom trawl survey and is intended to serve as a guideline for researchers interested in using the survey data and results. Included within is a confidence matrix of sampling efficiency and catch quantification for all fishes and invertebrates identified during the shelf survey.

Published
2016
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50. Species identification in the North Pacific Observer Program : training, protocols and data monitoring

Author

Stevenson, Duane E., 1970, Moon, M. (Michael), Ricket, M. (Melanie), and Vechter, M. (Michael)

Subjects
Fishes--Identification--Study and teaching--North Pacific Ocean
Abstract

The Alaska Fisheries Science Center’s Fisheries Monitoring and Analysis Division is responsible for development, implementation, and continuing operation of the North Pacific Observer Program. Observers in this Program are expected to accurately and consistently identify all commercially important fish and crab species as well as numerous other species, including forage fishes, elasmobranchs, and some species of sculpins. Because consistently accurate species identifications are such a critical facet of observer data collection, the Observer Program has implemented a series of policies and procedures to ensure that the species composition data collected by observers are as accurate and complete as possible. This document provides an overview of those procedures and policies. It is organized in three sections that correspond with the three phases of an observer's deployment sequence. The first section covers hiring and pre-deployment training, including hiring prerequisites, training procedures, certification exams, and field identification materials. The second section covers the actual deployment period, including species and species groups identified, confirmation procedures, in season advising, and the special cases of species groupings used for longline data. The third and final section covers post-deployment debriefing and quality control measures, such as error checks, staff review of species identification forms, photographs, and collected specimens, and the evaluation of observer performance.

Published
2016
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