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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 sites. [ABSTRACT FROM AUTHOR]

Species of the tubenose poacher genus Pallasina are assessed following examination of over 450 specimens from throughout the Pacific Rim, from the coast of California to the Chukchi Sea and Sea of Japan. The results presented here, including both morphological and mitochondrial DNA datasets, indicate that three species of Pallasina occur in the North Pacific and surrounding seas. Pallasina aix is found in the eastern North Pacific from California to southeast Alaska and in the Salish Sea. It has the shortest barbel of the three species and a unique haplotype in the mitochondrial COI region. Pallasina barbata is the most widespread species, ranging from the Gulf of Alaska to the Chukchi Sea and west to northern Japan. It is distinguished by having a moderate barbel length and can be separated from the other two species using a variety of meristic characters. Pallasina eryngia is found only in the central and northern Japanese Archipelago, and it is a relatively deep-water species. It is distinguished by having a long barbel, as well as relatively high counts of vertebrae and dermal plates. This study presents redescriptions of all three species and a key to their identification. [ABSTRACT FROM AUTHOR]

A new species, Careproctus ambustus, is described from 64 specimens based on evidence from morphological and molecular data. Specimens of Careproctus ambustus, new species, have been historically misidentified as the common Blacktail Snailfish, C. melanurus. The new species is distinguished from C. melanurus by its higher numbers of vertebrae (62–66 vs. 56–62 in C. melanurus), dorsal-fin rays (57–63 vs. 53–58), and anal-fin rays (51–55 vs. 46–51), and longer pelvic disc (14.1–21.2 vs. 12.6–20.7 % HL). In addition, the new species differs from C. melanurus by seven base pairs within a 492-base-pair region of the cytochrome oxidase c subunit 1 region, a 1.4% sequence divergence. Careproctus ambustus, new species, is found at depths of 58–1,172 m and ranges from Japan, through Alaska, to the west coast of Vancouver Island, British Columbia, where its distribution overlaps with C. melanurus, which ranges from southern Alaska and British Columbia to Baja California. [ABSTRACT FROM AUTHOR]

The population structure and demographic history of a pelagic lumpsucker, Aptocyclus ventricosus, were investigated on the basis of sequence variation in the mitochondrial cytochrome b gene (1038 bp). The haplotype network clearly recovered two haplotype groups, consisting of western and eastern North Pacific individuals, except for some specimens collected from offshore of Tohoku, northern Japan. The geographic distribution of haplotypes suggests that the ocean currents in the North Pacific have shaped the population structure of the species after historical vicariant events between the Kuril Islands and Kamchatka Peninsula. In addition, the demographic histories of the two haplotype groups were quite different, suggesting that the western North Pacific group experienced a population expansion starting around 10,000 years ago, while the population size of the eastern North Pacific group has remained more stable. [ABSTRACT FROM AUTHOR]

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]

The zoarcoid family Bathymasteridae contains seven species in three genera (Bathymaster, Rathbunella, Ronquilus) found in the North Pacific Ocean. Although several synapomorphies have been identified for the family, molecular analyses recover the family as a paraphyletic grade. The goals of this study are to provide a description of the skeleton of R. jordani as a baseline contribution for future systematic comparisons among all bathymasterid taxa and zoarcoids. We used our osteological study to discuss ontogenetically variable characters that appear to carry phylogenetic signal within Zoarcoidei. Finally, we discuss the systematic relationships of Bathymasteridae, including its monophyly and their systematic relationships. The vertebrae of Bathymasteridae develop in two distinct patterns. In Ronquilus and Bathymaster, the vertebrae initially form in the mid‐caudal region and development proceeds both anteriorly and posteriorly until the entire vertebral column is complete. In contrast, in Rathbunella the vertebrae initially form immediately posterior to the skull and development proceeds posteriorly; this is interpreted to be plesiomorphic. Other characters that were clarified (e.g., presence of well‐developed teeth on the gill rakers of Ronquilus) or described (e.g., variation in fusion caudal skeleton elements across Zoarcoidei) now must be evaluated in a taxonomically comprehensive systematic analysis of Zoarcoidei. [ABSTRACT FROM AUTHOR]

Recent deep-water surveys of the continental slope in the Bering Sea and the eastern North Pacific, conducted by the US National Marine Fisheries Service, Alaska Fisheries Science Center, and Fisheries and Oceans Canada, have broadened our understanding of the ichthyofauna in the region. Herein, we report significant new records of 2 species of skates based on morphological and molecular data. For Bathyraja spinosissima, the White Skate, we describe 2 specimens: a neonate male that constitutes a northern range extension for the species to Alaska in the Bering Sea; and an adult male representing a new record for the species in British Columbia. For B. microtrachys, the Fine-spined Skate, we describe 5 males taken in a single haul that represent the 1st record of the species in British Columbia. These specimens had been previously misidentified as B. violacea, the Okhotsk Skate, a species known only from the western Aleutian Islands and the western North Pacific. [ABSTRACT FROM AUTHOR]

The climate regime in the eastern Bering Sea has recently been dominated by a pattern of multi-year stanzas, in which several successive years of minimal sea-ice formation and warm summer temperatures (e.g., 2002-2005, 2014-2017) alternate with several years of relatively extensive sea-ice formation and cold summer temperatures (e.g., 2006-2013). This emerging climate pattern may be forcing long-term changes in the spatial distributions of the Bering Sea's marine fauna. The National Marine Fisheries Service's Alaska Fisheries Science Center recently conducted two bottom trawl surveys covering the entire Bering Sea shelf from the Alaska Peninsula to the Bering Strait. The first, in the summer of 2010, was conducted during a cold year when the majority of the continental shelf was covered by a pool of cold (< 2 °C) water. The second, in the summer of 2017, was during a warmer year with water temperatures above the long-term survey mean. These two surveys recorded significantly different spatial distributions for populations of several commercially important fish species, including walleye pollock (Gadus chalcogrammus), Pacific cod (Gadus macrocephalus), and several flatfish species, as well as jellyfishes. Population shifts included latitudinal displacement as well as variable recruitment success. The large-scale distributional shifts reported here for high-biomass species raise questions about long-term ecosystem impacts, and highlight the need for continued monitoring. They also raise questions about our management strategies for these and other species in Alaska's large marine ecosystems. [ABSTRACT FROM AUTHOR]

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 the interactions between fisheries and skate nursery areas in the eastern Bering Sea. Trained observers identified and assessed 2887 egg cases in a wide range of fisheries across all gear types, with the majority of egg cases being encountered on vessels targeting deepwater species, such as the arrowtooth flounder (Atheresthes stomias), Greenland halibut (Reinhardtius hippoglossoides), Pacific cod (Gadus macrocephalus), and sablefish (Anoplopoma fimbria). A large proportion of the egg cases identified were reported on boats using bottom trawling gear, but an even greater proportion were reported on longliners. Egg cases identified represent 10 skate taxa. Over half (67%) of them were identified as Alaska skate (Bathyraja parmifera), and 19% were identified as either Aleutian skate (B. aleutica) or Bering skate (B. interrupta). More than 42% of all the egg cases assessed were viable (contained a living skate); over 50% of egg cases of Alaska skate and of egg cases encountered on longliners were viable. The highest concentrations of egg cases generally were reported near known skate nursery areas, particularly in the Bering, Pribilof, and Pervenets Canyons. [ABSTRACT FROM AUTHOR]

Snailfishes of the genus Careproctus deposit egg masses inside the gill cavity of lithodid crabs. Previous attempts to identify the species depositing the eggs have been inconclusive because of the difficulties in identifying snailfish eggs and larvae. For this study, samples were collected from egg masses found in crabs in the commercial fishery and during benthic trawl survey work. Egg masses were found in Lithodes aequispinus (Golden King Crab) and, for the first time, in L. couesi (Scarlet King Crab). Mitochondrial DNA from the cytochrome c oxidase subunit I (COI) region was amplified from embryos and sequenced. Comparison of COI sequences from eggs to COI sequences from positively identified adult voucher specimens yielded identifications of 75 egg masses to species. A total of 38 egg masses were identified as Careproctus melanurus; 29 as C. colletti; seven as C. furcellus; and one as C. simus. Each egg mass contained eggs from only one species, and there was no indication of multiple maternal parentage. These results are the first positive identification of the snailfish species responsible for depositing egg masses in lithodid crabs. Identification of species involved may be useful in understanding the nature of this unique relationship between snailfishes and crabs. [ABSTRACT FROM AUTHOR]

Eastern North Pacific species of the fathead sculpin genus Malacocottus Bean are assessed following examination of over 300 specimens collected from throughout the known range of the genus, from the west coast of North America around the Pacific Rim to Japan, including the marginal waters of the Salish Sea, Bering Sea, Sea of Okhotsk, and Sea of Japan. The results of this study demonstrate that two species of Malacocottus occur in the eastern North Pacific. Malacocottus zonurus is found in the North Pacific from Washington State around the Pacific Rim to Japan, and in all marginal seas. Malacocottus kincaidi Gilbert and Thompson is apparently endemic to the Salish Sea, known only from Puget Sound and the Strait of Georgia. These two species differ in preopercular spine morphology and gill-raker counts. Malacocottus aleuticus Smith, based on a single juvenile specimen, is a synonym of M. zonurus. This study includes redescriptions of M. zonurus and M. kincaidi, comparisons of both species with M. gibber, and a key to the three known species of the genus. [ABSTRACT FROM AUTHOR]

ABSTRACT--Increased fisheries survey effort over the last decade by the US National Marine Fisheries Service (NMFS), Alaska Fisheries Science Center (AFSC), through its Resource Assessment and Conservation Engineering (RACE) and Fisheries Monitoring and Analysis (FMA) Divisions, has allowed biologists to collect voucher specimens and document the geographic distribution of marine fishes in Alaskan waters, including commercially important species as well as those more rarely encountered. A vouchering system allows for confirmation of field identifications, and access to specimens is ensured by their deposition at the University of Washington Burke Museum Fish Collection (UWFC). Herein we report the 1st Alaskan records for 10 species, the 1st Bering Sea records for 10 species, the 2nd or 3rd Alaskan records for 13 species, significant range extensions in the Bering Sea for 17 species, 9 species in the Aleutian Islands, 11 species in the Gulf of Alaska, and 8 species for which new records fill the gap in distribution across the North Pacific region. We also document specimens for 4 Alaska species previously cited in the literature without vouchers. A total of 83 species are discussed and photos are provided for 17 of the rarely encountered and poorly documented species. [ABSTRACT FROM AUTHOR]

The family Caristiidae, commonly known as manefishes or veilfins, includes seven species of mesopelagic, oceanic fishes found throughout the major ocean basins of the world. We present a partial revision of the family, including all of the "small mouth" species, which are distinguished from other species of the family by having an upper jaw that extends approximately to midorbit and is almost completely covered by the thin bones of the suborbital series, a broad suborbital space, and by the lack of palatine teeth. This group, previously thought to include only the genus Paracaristius, is described in full, including the establishment of a new genus and three new species. The new genus Neocaristius includes only Neocaristius heemstrai, a distinctive species that is distinguished from all other species In this group by dentition, lateral-line morphology, dorsal-fin origin, and orbit size, as well as other meristic and morphometric characters. Neocaristius heemstrai is a circumaustral species, known from the South Atlantic, South Pacific, and southern Indian Ocean. The genus Paracaristius includes four species, P. maderensls and three species newly described herein. Species of Paracaristius are distinguished from each other on the basis of meristics, dentition, presence or absence of papillae on the hyoid arch, and placement of the dorsal fin. Two species of Paracaristius, P. nemorosus, new species, and P. aquilus, new species, are apparently resticted to the eastern tropical Atlantic, while the other two, P. nudarcus, new species, and P. maderensls are more widespread. [ABSTRACT FROM AUTHOR]

Sequence variability in the cytochrome c oxidase I (COI) gene from 226 samples of the species previously considered Bathyraja parmifera (Rajidae) revealed three distinct haplotypes, one of which represents an undescribed species, the leopard skate. Further genetic examination of four closely related North Pacific and Bering Sea skate species, Bathyraja parmifera, B. simoterus, B. smirnovi, and the leopard skate in comparison with 19 related species indicates that together these four species comprise the subgenus Arctoraja. Phylogenetic analysis suggests that Arctoraja is monophyletic, but that the genus Bathyraja may be paraphyletic due to the phylogenetic position of Rhinoraja. [ABSTRACT FROM AUTHOR]

Six of the eight currently recognized species of the zoarcid genus Bothrocara are known from the eastern Bering Sea. Two of these species, B. brunneum and B. zestum, are widespread and commonly encountered on the upper continental slope, although B. zestum was not widely recognized as a distinct species in the region until 2004. During the summers of 2004 and 2008, large-scale bottom trawl surveys were conducted along the upper continental slope of the eastern Bering Sea from Bering Canyon to the U.S.-Russian border. Over the course of these surveys, distribution, relative abundance, length frequency, length-weight, and stomach contents information was collected for B. brunneum and B. zestum. Data collected on the surveys indicate that these two species have broadly overlapping geographic and bathymetric distributions in the region, but that their population numbers are substantially different. Length-weight regressions show that although these two species reach approximately the same maximum length, B. brunneum is substantially heavier than B. zestum at all lengths over about 40 cm. Stomach contents analysis indicates that the diet of B. brunneum consists primarily of various species of shrimps and mysids, while B. zestum is primarily piscivorous, consuming primarily bathylagids and other zoarcids. Therefore, despite their general morphological similarity, these two species function very differently in the eastern Bering Sea benthic ecosystem. [ABSTRACT FROM AUTHOR]

Lycodes diapterus, the type species of Furcimanus, has been divided into as many as three subspecies (L. diapterus diapterus, L. d. beringi, and L. d. nakamurae). Although L. d. nakamurae has been broadly recognized as a distinct species by recent authors, the status of L. d. beringi is unresolved, and several authors have noted the need for a comprehensive morphological study of L. diapterus. Based on an examination of nearly 500 specimens collected from Kamchatka to California, we herein recognize Lycodes beringi as a valid species distinguished from L. diapterus by meristics and squamation. Lycodes beringi is distributed from southeastern Kamchatka through the Bering Sea, Commander and Aleutian Islands, Gulf of Alaska, and south along the North American west coast to Puget Sound, while L. diapterus ranges from the Pacific coast of Vancouver Island south along the U.S. west coast to southern California. In this report we document the morphological variation present in L. diapterus and L. beringi and designate a lectotype for L. beringi, We also provide diagnoses, descriptions, and distribution information for both forms, and compare them with closely related congeners, providing comments on the subgenus Furcimanus. [ABSTRACT FROM AUTHOR]

Six years of bottom-trawl survey data, including over 6000 trawls covering over 200 km² of bottom area throughout Alaska's subarctic marine waters, were analyzed for patterns in species richness, diversity, density, and distribution of skates. The Bering Sea continental shelf and slope, Aleutian Islands, and Gulf of Alaska regions were stratified by geographic subregion and depth. Species richness and relative density of skates increased with depth to the shelf break in all regions. The Bering Sea shelf was dominated by the Alaska skate (Bathyraja parmifera), but species richness and diversity were low. On the Bering Sea slope, richness and diversity were higher in the shallow stratum, and relative density appeared higher in subregions dominated by canyons. In the Aleutian Islands and Gulf of Alaska, species richness and relative density were generally highest in the deepest depth strata. The data and distribution maps presented here are based on species-level data collected throughout the marine waters of Alaska, and this article represents the most comprehensive summary of the skate fauna of the region published to date. [ABSTRACT FROM AUTHOR]

Stlegicottus xenogrammus Bolin, 1936, was described from a single small, deteriorated specimen from the southern Bering Sea. No subsequent specimens have been identified. Comparison with the holotype of Rastrinus scutiger confirms that the two specimens represent the same species, and previously reported differences between the two are likely the result of the small size and deteriorated condition of the holotype of S. xenogrammus. Because Stlegicottus xenogrammus cannot be distinguished from Rastrinus scutiger by any reliable character, the two names are treated as synonyms, with R. scutiger having priority, and Stlegicottus becomes a junior synonym of Rastrinus. [ABSTRACT FROM AUTHOR]

A new species of eelpout, Lycodes akuugan, is described from the Aleutian Islands on the basis of 11 specimens collected during bottom-trawl surveys from 1994 through 2004. This species has a distinctive color pattern, characterized by a dark brown dorsum separated from a light gray ventrum by a distinct border running along the lateral surface of the head and most of the body, as well as several distinct narrow bars on the dorsal fin and a light blotch on the posterodorsal portion of the caudal fin. It is also characterized by having an elongate body, a ventrally placed lateral line, rounded pectoral fins, and relatively high meristics, as well as the presence of an interorbital cephalic sensory, pore and the absence of scales on the nape. Among sympatric congeners, L. akuugun is most similar to L. diapterus, L. brevipes, and L. concolor. It differs from all three species in color pattern and in the presence of an interorbital cephalic sensory pore. It can be distinguished from other congeners on the basis of coloration, lateral-line morphology, and meristics. [ABSTRACT FROM AUTHOR]

A new species of the skate genus Bathyraja, Bathyraja mariposa, is described from the Aleutian Islands and its geographic and bathymetric range documented. Bathyraja mariposa is similar to Bathyraja violacea and Rhinoraja taranetzi in its moderate maximum size and absence of thorns on the disc. However, it can be clearly distinguished from B. violacea by its distinctive color pattern, uniform covering of fine denticles, and clasper morphology. It can be distinguished from R. taranetzi and other similar western North Pacific species by the lack of a pseudosiphon on the clasper as well as by differences in various morphometric and meristic characters. [ABSTRACT FROM AUTHOR]

Abstract Aim Based on seven consecutive seasons of biotic survey and inventory of the terrestrial and freshwater plants and animals of the 30 major islands of the Kuril Archipelago, a description of the biodiversity and an analysis of the biogeography of this previously little known part of the world are provided. Location The Kuril Archipelago, a natural laboratory for investigations into the origin, subsequent evolution, and long-term maintenance of insular populations, forms the eastern boundary of the Okhotsk Sea, extending 1200 km between Hokkaido, Japan, and the Kamchatka Peninsula of Russia. A chain of more than 56 islands, the system is only slightly smaller than the Hawaiian Islands, covering an area of 15,600 km[sup 2] and providing 2409 km of coastline. Methods Collections of whole specimens of plants and animals, as well as tissue samples for future molecular studies, were made by teams of scientists from Russia, Japan, and the USA, averaging 34 people for each of the seven annual summer expeditions (1994–2000). Floral and faunal similarities between islands were evaluated by using Sorensen's coefficient of similarity. The similarity matrix resulting from pair-wise calculations was then subjected to UPGMA cluster analysis. Results Despite the relatively small geographical area of all islands combined, the Kuril Island biota is characterized by unusually high taxonomic diversity, yet endemism is very low. An example of a non-relict biota, it originated from two primary sources: a southern source, the Asian mainland by way of Sakhalin and Hokkaido, and a northern source by way of Kamchatka. The contribution of the southern source biota to the species diversity of the Kurils was considerably greater than the northern one. Main conclusion The Bussol Strait, lying between Urup and Simushir in the central Kurils, is the most significant biogeographical boundary within the Archipelago. Of lesser importance are two transitional zones, the De Vries Strait or ‘Miyabe Line’, which passes between Iturup and Urup in the southern Kurils, and the fourth Kuril Strait, between Onekotan and Paramushir in the northern Kurils. [ABSTRACT FROM AUTHOR]