Gadiform Fishes Research Articles

Influences of Ocean Currents on the Diets of Demersal Fish Communities in the Western North Pacific Revealed by Their Muscle Carbon and Nitrogen Isotopic Compositions

To study the influence of different ocean currents on the trophic spectra found in a sympatric fish community, we analyzed the radiocarbon contents (Δ14C) and stable carbon (δ13C) and nitrogen (δ15N) isotopic compositions in their bulk muscle tissues and the δ15N of individual amino acids in 26 species of demersal fish collected from off Tohoku (Pacific coast), northeastern Japan. The Δ14C values of the fish varied from –42 to +41‰, consistent with the Δ14C of the dissolved inorganic carbon in the cold Oyashio Current (typically about –50‰) and the warm Kuroshio Current (typically about +50‰). The trophic positions (TPs) of the fish estimated from the δ15N values of amino acids increased from 3.1 to 4.5 with increasing snout length. A negative correlation was observed between Δ14C and TP in gadiform fish and flatfish, suggesting that the Oyashio Current delivers a high TP diet to these fish groups. These results suggest that the trophic ecology of marine fish in the coastal western North Pacific is primarily controlled by the two major surface water currents, but is also significantly influenced by a combination of species-specific feeding and migration strategies.

Confronting Sources of Systematic Error to Resolve Historically Contentious Relationships: A Case Study Using Gadiform Fishes (Teleostei, Paracanthopterygii, Gadiformes).

Reliable estimation of phylogeny is central to avoid inaccuracy in downstream macroevolutionary inferences. However, limitations exist in the implementation of concatenated and summary coalescent approaches, and Bayesian and full coalescent inference methods may not yet be feasible for computation of phylogeny using complicated models and large data sets. Here, we explored methodological (e.g., optimality criteria, character sampling, model selection) and biological (e.g., heterotachy, branch length heterogeneity) sources of systematic error that can result in biased or incorrect parameter estimates when reconstructing phylogeny by using the gadiform fishes as a model clade. Gadiformes include some of the most economically important fishes in the world (e.g., Cods, Hakes, and Rattails). Despite many attempts, a robust higher-level phylogenetic framework was lacking due to limited character and taxonomic sampling, particularly from several species-poor families that have been recalcitrant to phylogenetic placement. We compiled the first phylogenomic data set, including 14,208 loci (n}{}>2.8 M bp) from 58 species representing all recognized gadiform families, to infer a time-calibrated phylogeny for the group. Data were generated with a gene-capture approach targeting coding DNA sequences from single-copy protein-coding genes. Species-tree and concatenated maximum-likelihood (ML) analyses resolved all family-level relationships within Gadiformes. While there were a few differences between topologies produced by the DNA and the amino acid data sets, most of the historically unresolved relationships among gadiform lineages were consistently well resolved with high support in our analyses regardless of the methodological and biological approaches used. However, at deeper levels, we observed inconsistency in branch support estimates between bootstrap and gene and site coefficient factors (gCF, sCF). Despite numerous short internodes, all relationships received unequivocal bootstrap support while gCF and sCF had very little support, reflecting hidden conflict across loci. Most of the gene-tree and species-tree discordance in our study is a result of short divergence times, and consequent lack of informative characters at deep levels, rather than incomplete lineage sorting. We use this phylogeny to establish a new higher-level classification of Gadiformes as a way of clarifying the evolutionary diversification of the order. We recognize 17 families in five suborders: Bregmacerotoidei, Gadoidei, Ranicipitoidei, Merluccioidei, and Macrouroidei (including two subclades). A time-calibrated analysis using 15 fossil taxa suggests that Gadiformes evolved n}{}sim 79.5 Ma in the late Cretaceous, but that most extant lineages diverged after the Cretaceous–Paleogene (K-Pg) mass extinction (66 Ma). Our results reiterate the importance of examining phylogenomic analyses for evidence of systematic error that can emerge as a result of unsuitable modeling of biological factors and/or methodological issues, even when data sets are large and yield high support for phylogenetic relationships. [Branch length heterogeneity; Codfishes; commercial fish species; Cretaceous-Paleogene (K-Pg); heterotachy; systematic error; target enrichment.]

<p class="ZootaxaTitle">Grenadiers (Teleostei: Gadiformes: Macrouridae) of Japan and adjacent waters, a taxonomic monograph

The taxonomy of the gadiform fish family Macrouridae (sensu stricto) in the northwestern Pacific off Japan and adjacent waters is critically reviewed on the basis of 7846 specimens. A total of 76 species belonging to 18 genera is recognized, including four new species of the genera Coelorinchus (2 species), Kuronezumia (1), and Nezumia (1). Coelorinchus lanceolatus sp. nov. superficially resembles Coe. anatirostris Jordan & Gilbert in Jordan & Starks, 1904, but differs most notably from that species in having a distinctly longer snout (107% of the postrostral length vs. 60–88%). Coelorinchus nox sp. nov. is closely similar to Coe. smithi Gilbert & Hubbs, 1920, but readily differs from the latter in that the occipital scales are covered with short, erect, needle-like spinules in widely divergent, comb-like rows (vs. moderately reclined, keel-like to knife-like spinules in saw-toothed rows). Kuronezumia endoi sp. nov. is a distinctive species among the genus, and is clearly diagnosed from other congeners in having the highest number of pelvic-fin rays (15 vs. ≤14). Nezumia rara sp. nov. closely resembles N. tomiyamai (Okamura, 1963), but they can be distinguished from each other by the combination of a number of morphometric characters, including the orbit-preopercle distance, interorbital width, pelvic-fin length, and length of gill slit. New and reconfirmed synonymies include: Coe. abbreviatus Chu & Lo in Chu, Chan & Chen, 1963 and Coe. intermedius Chu & Lo in Chu, Chan & Chen, 1963 with Coe. multispinulosus Katayama, 1942; Coe. productus Gilbert & Hubbs, 1916 with Coe. anatirostris; Coe. asteroides Okamura, 1963 with Coe. hige Matsubara, 1943; Coe. sparsilepis Okamura & Yatou, 1984 with Coe. parallelus (Günther, 1877); Coryphaenoides filamentosus Okamura, 1970 with Cor. cinereus (Gilbert, 1896); Cor. liocephalus (Günther, 1887) with Cor. leptolepis Günther, 1877; Cor. spinulosus (Gilbert & Burke, 1912) with Cor. acrolepis (Bean, 1884); and Ventrifossa fusca Okamura, 1982 with V. misakia (Jordan & Gilbert in Jordan & Starks, 1904). Lectotypes are designated for Coe. parallelus, Cor. asper Günther, 1877, Cor. liocephalus, and Cor. nasutus Günther, 1877. Previous records of N. burragei (Gilbert, 1905) and N. propinqua (Gilbert & Cramer, 1897) from Japan represent misidentifications, and these species are eliminated from the list of Japanese grenadiers. Coryphaenoides armatus (Hector, 1875) and Cor. leptolepis are recorded for the first time from the hadal zone. All species are illustrated, with full descriptions for 14 species. Dichotomous keys to genera and species are also provided. The distribution of each species in the study area is revised based on the specimens examined here, with re-identification of voucher specimens of most previous geographical records.

Revision of the fish family Euclichthyidae (Pisces: Gadiformes) with the description of two new species from the Western Pacific.

Members of the benthopelagic fish family Euclichthyidae, also known as the Eucla cods, occur on the upper continental slopes off Australasia at 220-1040 m depths. Euclichthyids essentially differ from other gadiform fishes in a combination of two almost contiguous dorsal fins with the second much longer based, a deeply notched anal fin with its anterior portion greatly elevated, jugular pelvic fins consisting of 3 partly united filiform upper rays and 3 free filamentous lower rays, an asymmetrical caudal fin with 5 hypurals fused into two plates, and no chin barbel, or vomerine and palatine tooth patches. Additional characters attributed to the group by other published studies include: no horizontal diaphragm within the posterior chamber of the swim bladder, no swim bladder-auditory capsule connection, presence of a luminous organ, and cranial muscle adductor arcus palatini divided by a strong ligament running from the lateral ethmoid and palatine to the medial face of the hyomandibular. Widely considered to be monotypic since its erection in 1984, the group consists of a single genus and three allopatric species, Euclichthys polynemus McCulloch, 1926 (Western and southern Australia, New Zealand), and two new taxa, E. microdorsalis sp. nov. (northeastern Australia) and E. robertsi sp. nov. (eastern Australia and New Caledonia). Eucla cods are morphologically conservative with both new species superficially resembling the type species, E. polynemus. Euclichthys microdorsalis sp. nov. is the most anatomically and morphologically divergent member of the group in having a shorter first dorsal fin, longer snout, relatively small eye compared to its interorbital width, and fewer caudal-fin rays and primary rakers on the outer gill arch than its congeners. Euclichthys robersti sp. nov. differs from E. polynemus in being smaller with a more slender head, and having a smaller eye, longer anal-fin base and tail, smaller scales, fewer primary rakers on the outer gill arch, more elongate oval otoliths, and usually having a X and/or Y bone in the caudal skeleton (both absent in other Euclichthys). Little is known of their biology but available material suggest that early juveniles remain pelagic in the open ocean with adults benthopelagic near the sea floor. Diagnoses and a key are provided for the three species.

Genetic diversity and population structure of burbot Lota lota in Germany: Implications for conservation and management

AbstractThe genetic structure of the gadiform fish species, burbot Lota lota L., was investigated across Germany to derive management options for facilitating the preservation of genetic diversity. Sequence analysis of the mitochondrial control region (n = 244) and microsatellite analysis (n = 861) of specimens from 20 sites revealed genetic structuring between major river basins, and particularly between lake and river habitats. The admixture zone between the Eurasian and West European phylogenetic clades in Lake Constance was confirmed and expanded to include the drainage basins of the rivers Rhine and Schlei/Trave. Haplotype distribution and private haplotypes in single river basins indicated population differentiation and imply that German burbot constituted an important part of the entire species' diversity. The derived genetic structuring has implications for future stocking programmes and the preservation of the adaptive potential of burbot, a guiding species for oligotrophic lakes in Europe.

First report of Eocene gadiform fishes from the Trans-Urals (Sverdlovsk and Tyumen regions, Russia)

AbstractThe recent 2014–2017 controlled excavations carried out in quarries of Sverdlovsk and Tyumen regions, Ural and Western Siberia, are contributing to the knowledge of the middle to late Eocene marine fauna from the Turgay Strait, mainly composed of invertebrates and cartilaginous and bony fishes. Here we present a preliminary report of the bony fishes collected during the campaigns carried out in two Eocene Trans-Urals localities. The sediments of these localities were deposited in a large epicontinental marine basin during the middle to late Eocene, when the Turgay Strait connected the Arctic waters to the North and the Peritethys to the South. Most of the bony fish material examined can be assigned to codfishes (Gadiformes) according to morphological comparison with living and fossil taxa. In particular, nearly complete three-dimensionally preserved lower jaws are confidently assigned to the Merlucciidae, whereas isolated vertebrae and bones are referred to as Gadiformes incertae sedis. This report documents the easternmost occurrence of this group of fishes in the northern hemisphere during the early phases of their radiation, revealing their presence into the Turgay Strait before its closure.

Species of Lepidapedon Stafford, 1904 (Digenea: Lepidapedidae) from deep-sea fishes in the Western Mediterranean: molecular and morphological evidence.

The species diversity of Lepidapedon Stafford, 1904 (Lepidapediae) in the Western Mediterranean was assessed based on samples from five deep-sea gadiform fishes collected between the Balearic Islands and the Catalonian coast of Spain: Lepidion lepidion (Risso) and Mora moro (Risso) (both Moridae); Coelorinchus mediterraneus Iwamoto & Ungaro and Trachyrincus scabrus (Rafinesque) (both Macrouridae); and Phycis blennoides (Brünnich) (Phycidae). Integration of morphological and molecular evidence (28S rRNA gene and the mitochondrial nad1 gene) revealed that the deep-sea fishes in the Western Mediterranean share two species of Lepidapedon. Lepidapedon desclersae Bray & Gibson, 1995 was recovered in all five fish species of three families [Moridae (L. lepidion and M. moro); Macrouridae (C. mediterraneus and T. scabrus); and Phycidae (P. blennoides)] and L. guevarai Lopez-Roman & Maillard, 1973 was recovered in three fish species of three families [Phycidae (P. blennoides); Macrouridae (T. scabrus); and Moridae (L. lepidion)]. Therefore, both species are considered to be euryxenic but restricted to gadiforms. The voucher material for the two species from different fish hosts is described in detail and the host-related variability based on the morphometric data is assessed.

New Data on the Morphology and Phylogenetic Connections of Postlepidapedon Opisthobifurcatum (Trematoda, Lepocreadioidea: Lepidapedidae), a Parasite of Antarctic and Sub-Antarctic Fishes.

SummaryThe trematode Postlepidapedon opisthobifurcatum (Zdzitowiecki, 1990) is a common intestinal parasite of the gadiform fishes of the Southern Ocean. In this work, we supplement the description of the species with the anatomy of the terminal part of the reproductive system and with molecular data. The male terminal genitalia are characterised by the presence of the external seminal vesicle and cirrus-sac. The external seminal vesicle is surrounded by aciniform groups of outer prostatic cells. Groups of outer prostatic cells and proximal parts of their ducts are associated with a thin-walled membrane that is connected to the proximal edge of the сirrus-sac. The cirrus-sac is claviform, with a long proximal part accommodating the tubular, thin-walled internal seminal vesicle and ducts of outer prostatic cells. The female terminal genitalia are represented by a thick-walled metraterm, which is surrounded by aciniform groups of glandular cells. Phylogenetic analysis based on 28S rDNA partial sequences data placed P. opisthobifurcatum into the monophyletic group Lepidapedidae, including the species Myzoxenus insolens (Crowcroft, 1945), Intusatrium robustum Durio et Manter, 1968, and Postlepidapedon uberis Bray, Cribb et Barker, 1997. However, we were unable to detect direct phylogenetic connections between P. opisthobifurcatum and P. uberis.

Zdzitowieckitrema incognitum gen. et sp. nov. (Trematoda, Xiphidiata) from the Antarctic fish Muraenolepis marmorata Günther, 1880 (Gadiformes: Muraenolepidae): ordinary morphology but unclear family affiliation

Zdzitowieckitrema incognitum n. gen., n. sp. infects the intestine of the gadiform fish Muraenolepis marmorata in Antarctic seas. Morphologically, this parasite corresponds to the diagnosis of the subfamily Plagioporinae sensu Cribb, 2005 (Opecoelidae, Opecoeloidea). Phylogenetic analysis based on 28S rDNA partial sequences revealed that Z. incognitum n. gen., n. sp. shares a recent common ancestor with representatives of the genus Biospeedotrema Bray, Waeschenbach, Dyal, Littlewood & Morand, 2014 (previously assigned to Stenakrinae, Opecoelidae, Opecoeloidea), and that these trematodes collectively form a sister group to the Gorgoderoidea clade of flukes. The most significant differences between Z. incognitum n. gen., n. sp. and Biospeedotrema spp. are the extension of vitelline fields and intestinal branches, position of the testes and the genital pore, morphology of the internal seminal vesicle, and the ovarian complex.

Sex steroids differentially regulate fshb, lhb and gnrhr expression in Atlantic cod (Gadus morhua).

Depending on the stage of gonad maturation, as well as other factors, gonadal steroids can exert either a positive or negative feedback at the brain and pituitary level. While this has been demonstrated in many teleost species, little is known about the nature of steroid feedback in Gadiform fish. Using an optimized in vitro model system of the Atlantic cod pituitary, the present study investigated the potential effects of two physiologically relevant doses of estradiol, testosterone (TS) or dihydrotestosterone (DHTS) on cell viability and gene expression of gonadotropin subunits (fshb/lhb) and two suggested reproduction-relevant gonadotropin-releasing hormone receptors (gnrhr1b/gnrhr2a) during three stages of sexual maturity. In general, all steroids stimulated cell viability in terms of metabolic activity and membrane integrity. Furthermore, all steroids affected fshb expression, with the effect depending on both the specific steroid, dose and maturity status. Conversely, only DHTS exposure affected lhb levels, and this occurred only during the spawning season. Using single-cell qPCR, co-transcription of gnrhr1b and gnrhr2a was confirmed to both fshb- and lhb- expressing gonadotropes, with gnrhr2a being the most prominently expressed isoform. While steroid exposure had no effect on gnrhr1b expression, all steroids affected gnrhr2a transcript levels in at least one maturity stage. These and previous results from our group point to Gnrhr2a as the main modulator of gonadotropin regulation in cod and that regulation of its gene expression level might function as a direct mechanism for steroid feedback at the pituitary level.

Molecular adaptation to high pressure in cytochrome P450 1A and aryl hydrocarbon receptor systems of the deep-sea fish Coryphaenoides armatus

Limited knowledge of the molecular evolution of deep-sea fish proteomes so far suggests that a few widespread residue substitutions in cytosolic proteins binding hydrophilic ligands contribute to resistance to the effects of high hydrostatic pressure (HP). Structure-function studies with additional protein systems, including membrane bound proteins, are essential to provide a more general picture of adaptation in these extremophiles. We explored molecular features of HP adaptation in proteins binding hydrophobic ligands, either in lipid bilayers (cytochrome P450 1A - CYP1A) or in the cytosol (the aryl hydrocarbon receptor - AHR), and their partners P450 oxidoreductase (POR) and AHR nuclear translocator (ARNT), respectively. Cloning studies identified the full-length coding sequence of AHR, CYP1A and POR, and a partial sequence of ARNT from Coryphaenoides armatus, an abyssal gadiform fish thriving down to 5000m depth. Inferred protein sequences were aligned with many non-deep-sea homologs to identify unique amino acid substitutions of possible relevance in HP adaptation. Positionally unique substitutions of various physicochemical properties were found in all four proteins, usually at sites of strong-to-absolute residue conservation. Some were in domains deemed important for protein-protein interaction or ligand binding. In addition, some involved removal or addition of beta-branched residues; local modifications of beta-branched residue patterns could be important to HP adaptation. In silico predictions further suggested that some unique substitutions might substantially modulate the flexibility of the polypeptide segment in which they are found. Repetitive motifs unique to the abyssal fish AHR were predicted to be rich in glycosylation sites, suggesting that post-translational changes could be involved in adaptation as well. Recombinant CYP1A and AHR showed functional properties (spectral characteristics, catalytic activity and ligand binding) that demonstrate proper folding at 1atm, indicating that they could be used as deep-sea fish protein models to further evaluate protein function under pressure. This article is part of a Special Issue entitled: Cytochrome P450 biodiversity and biotechnology, edited by Erika Plettner, Gianfranco Gilardi, Luet Wong, Vlada Urlacher, Jared Goldstone".

Heterochromatin organization and chromosome mapping of rRNA genes and telomeric DNA sequences in the burbotLota lota(Linnaeus, 1758) (Teleostei: Gadiformes: Lotidae)

AbstractThe knowledge about the genome of the burbot Lota lota (Linnaeus, 1758), the only freshwater gadiform fish (Gadidae, Gadiformes), is limited to chromosome number (2n = 48, NF = 78). In this work analysis of burbot chromosomes by C-banding, DAPI staining and restriction endonuclease digestion proved both heterogeneity of the heterochromatin and interchromosomal differences in the vulnerability to the endonuclease treatment. Silver nitrate and chromomycine A3 staining and fluorescence in situ hybridization using 28S rDNA probes showed that nucleolus organizer regions appear in one pair of burbot chromosomes. There is also a single locus for 5S rDNA repeats exhibited in burbot; however, major and minor rRNA gene families are not linked. The single and separated location of major and minor rDNA families suggests that the burbot karyotype still retains some characteristics of the putative ancestral karyotype. Although the increased number of the chromosome arms in relation to the ancestral karyotype su...

Distribution, relative abundance and diversity of deep sea species at Sao Pedro and Sao Paulo Archipelago, Brazil

The goal of the present study is to investigate vertical distribution, relative abundance and diversity of deep-sea species caught using baited traps at Sao Pedro and Sao Paulo Archipelago (SPSPA). The surveys were carried out between January 2012 and June 2014 at depths ranging from 170 to 700 m, comprising 53 hauls. Five species of crustaceans, ten of fishes and three of mollusks were caught. The deep-sea geryonid crab Chaceon gordonae was the most abundant species, followed by the Gadiform (Moridae) fish Physiculus sp. The results showed a clear bathymetric stratification, with some species being restricted to shallower layers (170-300 m) and others showing a wider distribution (200-700 m). Several factors can influence the vertical distribution of these species, including oceanographic and biological characteristics. In the future, more studies should be conducted in order to elucidate the interaction between distribution, relative abundance and diversity with various elements that make up the dynamics of this complex ecosystem.

Demersal fish communities of the shelf and slope of South Georgia and Shag Rocks (Southern Ocean)

This research is the first to investigate deepwater demersal fish distribution and community structure around South Georgia and Shag Rocks. Analysis of catch data from a trawl survey conducted in 2003 indicated that depth and location have a marked influence over demersal fish community structure in the region. Three distinct, depth-stratified fish assemblages were observed. The demersal fish assemblage found on the shelf to depths of around 400 m was dominated by nototheniids and was comprised largely of species endemic to the Southern Ocean and Scotia Sea. At the greatest depths sampled (>600 m) the demersal fish community was dominated by gadiform fishes including members of the Macrouridae and Moridae, many of which are not endemic to the Southern Ocean. From 400 to 600 m there was a transitional zone with demersal fish representatives of both the shelf and deeper slope communities. Clear geographic differences in the shelf community were apparent with differences observed in community structure between South Georgia and Shag Rocks to depths of around 400 m. These data provide valuable baseline information to aid environmental management decisions and assess potential impacts of rapid ocean warming around South Georgia.

Before the freeze: otoliths from the Eocene of Seymour Island, Antarctica, reveal dominance of gadiform fishes (Teleostei)

The first record of fossil teleostean otoliths from Antarctica is reported. The fossils were obtained from late Early Eocene shell beds of the La Meseta Formation, Seymour Island that represent the last temperate marine climate phase in Antarctica prior to the onset of cooling and subsequent glaciation during the late Eocene. A total of 17 otolith-based teleost taxa are recognized, with 10 being identifiable to species level containing nine new species and one new genus: Argentina antarctica sp. nov., Diaphus? marambionis sp. nov., Macruronus eastmani sp. nov., Coelorinchus balushkini sp. nov., Coelorinchus nordenskjoeldi sp. nov., Palimphemus seymourensis sp. nov., Hoplobrotula? antipoda sp. nov., Notoberyx cionei gen. et sp. nov. and Cepola anderssoni sp. nov. Macruronus eastmani sp. nov. is also known from the late Eocene of Southern Australia, and Tripterophycis immutatus Schwarzhans, widespread in the southern oceans during the Eocene, has been recorded from New Zealand, southern Australia, and now Antarctica. The otolith assemblage shows a typical composition of temperate fishes dominated by gadiforms, very similar at genus and family levels to associations known from middle Eocene strata of New Zealand and the late Eocene of southern Australia, but also to the temperate Northern Hemisphere associations from the Paleocene of Denmark. The Seymour Island fauna bridges a gap in the record of global temperate marine teleost faunas during the early Eocene climate maximum. The dominant gadiforms are interpreted as the main temperate faunal component, as in the Paleocene of Denmark. Here they are represented by the families Moridae, Merlucciidae (Macruroninae), Macrouridae and Gadidae. Nowadays Gadidae are a chiefly Northern Hemisphere temperate family. Moridae, Macruroninae and Macrouridae live today on the lower shelf to deep-water or mesopelagically with Macruroninae being restricted to the Southern Ocean. The extant endemic Antarctic gadiform family Muraenolepididae is missing, as are the dominant modern Antarctic fishes of the perciform suborder Notothenioidei. Recently, there has been much debate on isolated jaw bones of teleost fishes found in the La Meseta Formation and whether they would represent gadiforms (Merlucciidae in this case) or some early, primitive notothenioid. Otoliths are known to often complement rather than duplicate skeletal finds. With this in mind, we conclude that our otolith data support the presence of gadiforms in the early Eocene of Antarctica while it does not rule out the presence of notothenioids at the same time.http://zoobank.org/urn:lsid:zoobank.org:pub:A30E5364-0003-4467-B902-43A41AD456CC

Stomach Contents of a Cuvier's Beaked Whale (Ziphius cavirostris) Stranded in Monterey Bay, California

From 1942 to 2010 there were 23 reported strandings of Cuvier’s Beaked Whale, Ziphius cavirostris (Odontoceti: Ziphiidae), in the Pacific Northwest (Oregon and Washington), and 25 reported strandings in California between 1982 and 2010 (Moore and Barlow 2013). Although Z. cavirostris appears to be the most cosmopolitan of the beaked whales, occurring in all oceans except in high polar regions (Leatherwood and Reeves 1983; Heyning 1989), global phylogenetic analyses reveal low maternal gene flow among populations confined to isolated ocean basins (Dalebout and others 2005). Extensive surveys throughout the California Current System (CCS) show that Z. cavirostris is distributed offshore over the continental slope, occurring more frequently closer to shore and aggregated in areas of complex bathymetry (for example, Monterey Bay, California and within the Southern California Bight, see Fig. 2 in Moore and Barlow 2013). In the northern CCS, Moore and Barlow (2013) estimated that the Z. cavirostris population likely has decreased by approximately 30% from 10,771 in 1991 to approximately 7550 individuals in 2008, and they suggested that one potential cause could be ecosystem change, thus highlighting the need for additional information on food habits. Heyning (1989) first summarized prey information for Z. cavirostris from around the world, a list that included 10 cephalopod families (16 genera), gadiform and atheriniform fishes, and 2 accounts of crustacean prey. Santos and others (2001) reported prey remains from 3 Z. cavirostris stranded in the eastern Atlantic and provided a review of known prey remains for the species. MacLeod and others (2003) extended the review of Santos and others (2001) to include comparison of Z. cavirostris with 2 additional beaked whales: Mesoplodon spp. and Hyperoodon planifrons. Combining these records with 7 Z. cavirostris stomachs evaluated by Santos and others (2007), the known diet of Z. cavirostris is based on prey remains recovered from only 45 individuals world-wide; diets consisted of 46 cephalopod species (15 families), infrequent crustacean remains, and rare representation among mostly unidentified fishes (MacLeod and others 2003). Compared with records from the Atlantic, food habits of Z. cavirostris off Alaska and in the eastern North Pacific are less well known (n 5 5 individuals, and only 1 from California). Fiscus (1997) identified 6 cephalopod families (11 genera) from a subset of the stomach remains collected and described by Kenyon (1961) from a mature female Z. cavirostris that stranded in March 1959 on Amchitka Island, Aleutian Islands, Alaska. Foster and Hare (1990) identified 3 of the same cephalopod families (4 genera) as reported by Fiscus (1997) from a Z. cavirostris stranded in Kodiak, Alaska. In the Gulf of Mexico, Fertl and others (1997) identified a single beak of Loligo peali from an individual that stranded in Texas. An adult female Z. cavirostris (Moss Landing Marine Laboratory Museum [MLMLM] #499, standard length 600 cm) stranded dead on 15 January 1998 at Marina State Beach, California (UTM: Zone 10S, 607191E, 4062264N, WGS84). During a 2-d field necropsy, to minimize the loss of contents, we tied-off both the esophageal and duodenal ends of the stomach before removing it on 16 January 1998. Prey remains were also collected from the whale’s oral cavity. The stomach contents from 5 pyloric compartments (see Kenyon 1961 for a description of the stomach of an adult female Z. cavirostris) were gently rinsed and sifted through a 500-mm sieve. Cephalopod remains (whole beaks, beak fragments, and eye lenses) and fish remains (bones and eye lenses) were preserved in 50% isopropyl alcohol and fish otoliths were stored dry. Cephalopods were identified to lowest taxon using the GENERAL NOTES

Comparing early life traits of hakes from Chilean Patagonian fjords inferred by otolith microstructure analysis

Comparison of larval growth and back-calculated hatch dates on the basis of microstructure analysis of sagitta otoliths were carried out in wild-caught larvae of three commercially important gadiform fishes from Northern Patagonia, South Pacific, Chilean hake Merluccius gayi, southern hake Merluccius australis, and Patagonian grenadier Macruronus magellanicus. Because of the morphological similarities in their larval stages, we hypothesize that early life traits (ELT) will be different among the hake species in order to avoid/reduce interspecific competition. During October–November 2011, there was differences in the spatial distribution of the surviving larvae from the three species along the inner sea; while larval Chilean hake were concentrated in the warmer and fresher seawaters of the Reloncaví fjord, larval Patagonian grenadier were aggregated southward, in the Ancud Gulf, while larval southern hake were found throughout the area, but in low density. Temporal differences were evident in the back-calculated hatch days among species; larval hakes of genus Merluccius hatched during late October, while larval grenadier hatched between August and September. Estimated larval growth rates differed among hake species; larval M. magellanicus experienced the fastest growth rates (0.334±0.01mmd−1), while larval M. australis experienced growth rates of 0.220±0.01mmd−1, and larval M. gayi showed the slowest growth rates (0.180±0.01mmd−1). Therefore, resource partitioning both in time and space are occurring among early life stages of M. gayi, M. australis and M. magellanicus during austral spring season in Northern Patagonian fjords of Chile.

Trophic habits of the Ommastrephid squid Illex coindetii and Todarodes sagittatus in the northwestern Mediterranean Sea

Squids Illex coindetii and Todarodes sagittatus were collected from commercial trawls in the NW Mediterranean Sea and their stomach contents were analyzed to describe and compare their feeding habits. Fish, crustaceans and squids were found in the stomach contents of both squid species; however T. sagittatus had a wider trophic spectrum composed by fifteen prey items more than I. coindetii. This difference was attributed to the availability of feeding resources in the water column and the larger size and deeper distribution of T. sagittatus. The index of relative importance showed that the crustacean Pasiphaea multidentata was the most important prey for both squids, and that I. coindetii fed secondly on Anchilomera blossevillei, Pasiphaea sivado and the fish Lestidiops sp., while T. sagittatus fed secondly on Phronima sedentaria and the fish Arctozenus risso. The feeding habits of the two squids varied for two prey items at the size interval between 9.1 and 21cm ML. This difference was due to the presence of the amphipod P. sedentaria and the squid Ancistroteuthis lichtensteinii in the stomach contents of T. sagittatus, which are species with deeper distributions. T. sagittatus larger than 21cm ML preyed on other crustaceans and fish, such as big Pandalidae crustaceans and gadiform fish. Finally, the %FO analysis showed that there were fifteen common prey species in the feeding habits of the two squids, but they did not have the same importance for each squid. I. coindetii fed mainly on Lestidiops sp., Chauliodus sloani and P. multidentata and T. sagittatus fed on A. risso and P. sedentaria. These species correspond to mesopelagic fish, decapod crustaceans and amphipods. This suggests that these species are easy to prey at different levels in the water column, which affects the predation and distribution of I. coindetii and T. sagittatus.

Eocene relatives of cod icefishes (Perciformes: Notothenioidei) from Seymour Island, Antarctica

Fragmentary skull bones and vertebra from the Upper Eocene La Meseta Formation on Seymour (Marambio) Island, Antarctic Peninsula have been described as gadiform fishes, informally named “ Mesetaichthys ”. Here we describe jaws as Mesetaichthys jerzmanskae n. g. and n. sp., and refer this taxon to the perciform suborder Notothenioidei. This group is almost unknown as fossils. Similarities to the living, ‘primitive’ nototheniid Dissostichus eleginoides are indicated in the dentition. Gadiform evolution in the Paleocene-Eocene, and the possibility of a correlation between the origin and evolution of notothenioids in connection with the deterioration of the climate in Antarctica during the Late Eocene-Oligocene is discussed.

Global assessment of molecularly identified Anisakis Dujardin, 1845 (Nematoda: Anisakidae) in their teleost intermediate hosts

Here, we present the ITS ribosomal DNA (rDNA) sequence data on 330 larvae of nematodes of the genus Anisakis Dujardin, 1845 collected from 26 different bony fish species from 21 sampling locations and different climatic zones. New host records are provided for Anisakis simplex (Rudolphi, 1809) sensu stricto (s.s.) and A. pegreffli Campana-Rouget et Biocca, 1955 from Anoplopoma fimbria (Pallas) (Santa Barbara, East Pacific), A. typica (Diesing, 1860) from Caesio cuning (Bloch), Lepturacanthus savala (Cuvier) and Katsuwonus pelamis (Linnaeus) (Indonesia, West Pacific), A. simplex s.s. from Cololabis saira (Brevoort) (Hawaii, Central Pacific), A. simplex C of Nascetti et al. (1986) from Sebastolobus alascanus Bean (Santa Barbara, East Pacific) and A. physeteris Baylis, 1923 from Synaphobranchus kaupii Johnson (Namibia, East Atlantic). Comparison with host records from 60 previous molecular studies of Anisakis species reveals the teleost host range so far recorded for the genus. Perciform (57 species) and gadiform (21) fishes were the most frequently infected orders, followed by pleuronectiforms (15) and scorpaeniforms (15). Most commonly infected fish families were Scombridae (12), Gadidae (10), Carangidae (8) and Clupeidae (7), with Merluccius merluccius (Linnaeus) alone harbouring eight Anisakis species. Different intermediate host compositions implicate differing life cycles for the so far molecularly identified Anisakis sibling species.