Duane E. Stevenson

Systematic review of the genus Bothrocara Bean 1890 (Teleostei: Zoarcidae)

The systematics of the eelpout genus Bothrocara Bean 1890 is reviewed on the basis of 941 specimens. Eight mostly eurybathic, demersal species are recognized, distributed mainly along the continental slopes of the North and South Pacific oceans, with one species entering the South Atlantic. Distributions are: B. brunneum ranges from the Sea of Okhotsk to the Gulf of Panama at depths of 199–1,829xa0m; B. elongatum ranges from the Gulf of Panama to Chile at depths of 720–1,866xa0m; B. hollandi ranges from the Sea of Japan to the southeastern Bering Sea at depths of 150–1,980xa0m; B. molle ranges from the western Bering Sea to the South Atlantic at depths of 106–2,688xa0m; B. nyx is known only from the eastern Bering Sea at depths of 790–1,508xa0m; B. pusillum ranges from the northern Bering Sea to British Columbia, Canada, at depths of 55–642xa0m; B. tanakae is found along the northern coasts of Honshu and Hokkaido islands, Japan, at depths of 274–892xa0m; B. zestum ranges from the Izu Islands, Japan, and central Honshu, Japan, to the Gulf of Alaska at depths of 199–1,620xa0m (an unidentifiable specimen from off Taiwan may be B. zestum). The species are distinguished from one another mainly on the basis of head pore patterns, gill raker morphology, coloration and various meristic and morphometric values. A determination key to the species is provided.

Molecular systematics of the skate subgenus Arctoraja (Bathyraja: Rajidae) and support for an undescribed species, the leopard skate, with comments on the phylogenetics of Bathyraja

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.

Range Extensions and Significant Distributional Records for Eighty-Two Species of Fishes in Alaskan Marine Waters

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.

Molecular insights into geographic and morphological variation within the Eumicrotremus asperrimus species complex (Cottoidei: Cyclopteridae)

A molecular phylogeny of lumpsukers, Eumicrotremus asperrimus and related species (family Cyclopteridae), is presented on the basis of sequence variations in the cytochrome b and cytochrome c oxidase subunit 1 genes (1,659 base pairs) of mitochondrial DNA using specimens collected from across the North Pacific, including the Sea of Japan, Sea of Okhotsk, Bering Sea, and Gulf of Alaska. Specimens identified as Eumicrotremus phrynoides, Cyclopteropsis bergi, Cyclopteropsis lindbergi, and Lethotremus muticus on the basis of the presence or absence of spiny tubercles and height of the first dorsal fin did not exhibit reciprocal monophyly, but were randomly clustered with E. asperrimus. This collection of forms is therefore referred to as the “E. asperrimus species complex.” DNA sequence data presented here divided the E. asperrimus species complex into two distinct clades, corresponding to the eastern North Pacific (the Bering Sea, Aleutian Islands, and Gulf of Alaska) and the western North Pacific (the Seas of Japan and Okhotsk) regions. Slight morphometric differences between eastern and western clades were also evident, indicating that they represent at least two different species. The genetic level of divergence between the two clades suggests that the speciation event occurred during the early Pleistocene to late Pliocene. Although the presence and morphology of tubercles have been used extensively for species discrimination in Cyclopteridae, our results suggest that this character complex is confounded by intraspecific variation. Examined samples showed some sexual dimorphism in the relative development of the tubercles, although the pattern was different between the eastern and western North Pacific clades. These results underscore the need for a thorough re-examination of the taxonomy of Pacific cyclopterids, using molecular data to supplement potentially misleading tubercle morphology.

Osteology of the prowfish, Zaprora silenus (Cottiformes: Zoarcoidei: Zaproridae).

The prowfish, Zaprora silenus, is the sole member of the family Zaproridae. It is a large, relatively elongate species with a robust head and body, and it feeds primarily on jellyfishes. Although the larvae and juveniles are pelagic, the adults are demersal, and the species is widely distributed from Southern California around the Pacific Rim to Hokkaido, Japan. The stichaeid affinities of this species have long been recognized, and the family is currently placed, along with the Stichaeidae, in the Zoarcoidei. Previous anatomical studies of Zaprora have been based on relatively few specimens from a limited geographic range and have not included cleared and stained (c&s) specimens. Here, we provide a complete description of the osteology of the prowfish, based on a large series of specimens representing a broad ontogenetic range, including a series of c&s specimens. Our results contradict the findings of previous authors in the structure of the pharyngeal teeth, presence of the pelvic girdle, and the placement of the first dorsal pterygiophore. However, we concur with the findings of previous morphological and molecular phylogenetic studies, which indicate that the prowfish is probably most closely related to at least some members of the Stichaeidae. J. Morphol. 274:1143–1163, 2013.

The ronquils: a review of the North Pacific fish family Bathymasteridae (Actinopterygii: Perciformes: Zoarcoidei)

ABSTRACT The fish family Bathymasteridae, commonly known as ronquils, is reviewed based on an examination of nearly 500 adult and larval specimens. An identification key based on adults is provided. Information on adult morphology, including a detailed description of the cephalic lateralis system for all members of the family, is included as well as information on the early life history stages of each genus. The family Bathymasteridae is distinguished within the suborder Zoarcoidei by the presence of ctenoid scales; well-developed pelvic bones and pelvic fins; numerous vomerine, palatine, and dentary teeth; and several internal osteological features. The Bathymasteridae includes seven species classified in the genera Ronquilus, Rathbunella, and Bathymaster, and is broadly distributed in the North Pacific, from Baja California to the Sea of Japan. The monotypic genus Ronquilus is found from southern California to the Gulf of Alaska. Rathbunella contains two species restricted to the coasts of California and Baja California. Bathymaster is the most diverse and broadly distributed genus, containing four species ranging from British Columbia around the Pacific Rim to the northern Sea of Japan.

Reproductive Parasitism between Distant Phyla: Molecular Identification of Snailfish (Liparidae) Egg Masses in the Gill Cavities of King Crabs (Lithodidae)

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.

Distribution and food habits of two similar species of Bothrocara (Perciformes: Zoarcidae) in the eastern Bering Sea

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 40xa0cm. 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.