National Marine Fisheries Service

About: National Marine Fisheries Service is a government organization based out in Silver Spring, Maryland, United States. It is known for research contribution in the topics: Population & Fisheries management. The organization has 3949 authors who have published 7053 publications receiving 305073 citations. The organization is also known as: NOAA Fisheries & NOAA National Marine Fisheries Service.

Habitat-specific distribution of Pacific ocean perch (Sebastes alutus) in Pribilof Canyon, Bering Sea

Abstract: Shelf edge canyons are well-known sites of enhanced biomass due to on-shore transport and concentration of zooplankton along their axes, both of which contribute to the high densities of nekton frequently found in these canyons. Using a combination of acoustics, trawling, and in situ observations with a remotely operated vehicle (ROV), the distribution of pelagic and demersal biota within Pribilof Canyon in the Bering Sea was examined in September of 1995 and 1997. Near-bottom acoustic scattering patterns in the 38kHz data showed high concentrations of biomass beginning around the 180m bottom depth contour and continuing to about 220m, which were presumed to be adult fish based on their target strength distributions. The 120kHz data also showed very strong scattering in the water column between 150 and 175m, which was absent from the 38kHz data, and therefore attributed mainly to zooplankton. The dominant taxa collected in bottom trawls and mid-water plankton tows were adult rockfishes (Pacific ocean perch, Sebastes alutus) and euphausiids (Thysanoessa spp.), respectively. In situ videos revealed dense aggregations of these rockfishes inhabiting a ‘‘forest’’ of attached sea whips, Halipteris willemoesi, during night deployments of the ROV, while areas with damaged sea whips had far fewer rockfish, and areas without this biotic habitat structure had no rockfish. During the day, the rockfishes were seen above the ‘‘forest’’, where they were apparently feeding on dense swarms of euphausiids. It appears that these rockfish utilize this predictable and abundant food resource in the canyon during the day and are associated with the sea whip habitat at night during periods of inactivity. More research is needed on these slowgrowing biotic habitats and how fishing activities in the Bering Sea and elsewhere may impact these habitats. # 2001 Elsevier Science Ltd. All rights reserved.

Preliminary evaluation of the use of macrophage aggregates (MA) as fish health monitors.

Abstract: Discrete, round to ovoid macrophage aggregations (MA) containing pigment are commonly found widely distr ibuted in the spleen, l i ve r , and kidney of the higher te leos t i i (Agius 1980). These cel lu lar aggregations have been variously named (Grove 1968), most recently melano-macrophage centers (MMC) by Roberts (1975). The la t ter author, El l ls (1974), and Ferguson (1976) have suggested that MA have analogies to the germinal centers of homeotherms.

A genetic basis for the phenotypic differentiation between siscowet and lean lake trout (Salvelinus namaycush)

Abstract: In Lake Superior there are three principal forms of lake trout (Salvelinus namaycush): lean, siscowet and humper. Wild lean and siscowet differ in the shape and relative size of the head, size of the fins, location and size of the eyes, caudal peduncle shape and lipid content of the musculature. To investigate the basis for these phenotypic differences, lean and siscowet lake trout, derived from gametes of wild populations in Lake Superior, were reared communally under identical environmental conditions for 2.5 years. Fish were analysed for growth, morphometry and lipid content, and differences in liver transcriptomics were investigated using Roche 454 GS-FLX pyrosequencing. The results demonstrate that key phenotypic differences between wild lean and siscowet lake trout such as condition factor, morphometry and lipid levels, persist in these two forms when reared in the laboratory under identical environmental conditions. This strongly suggests that these differences are genetic and not a result of environmental plasticity. Transcriptomic analysis involving the comparison of hepatic gene frequencies (RNA-seq) and expression (quantitative reverse transcription-polymerase chain reaction (qPCR)) between the two lake trout forms, indicated two primary gene groups that were differentially expressed; those involving lipid synthesis, metabolism and transport (acyl-CoA desaturase, acyl-CoA binding protein, peroxisome proliferator-activated receptor gamma, and apolipoproteins), and those involved with immunity (complement component C3, proteasome, FK506 binding protein 5 and C1q proteins). The results demonstrate that RNA-seq can be used to identify differentially expressed genes; however, some discrepancies between RNA-seq analysis and qPCR indicate that methods for deep sequencing may need to be refined and/or different RNA-seq platforms utilized.

Cryptic and pseudo-cryptic diversity in diatoms—with descriptions of pseudo-nitzschia hasleana sp. nov. and p. fryxelliana sp. nov.1

Abstract: A high degree of pseudo-cryptic diversity was reported in the well-studied diatom genus Pseudo-nitzschia. Studies off the coast of Washington State revealed the presence of hitherto undescribed diversity of Pseudo-nitzschia. Forty-one clonal strains, representing six different taxa of the P. pseudodelicatissima complex, were studied morphologically using LM and EM, and genetically using genes from three different cellular compartments: the nucleus (D1-D3 of the LSU of rDNA and internal transcribed spacers [ITSs] of rDNA), the mitochondria (cytochrome c oxidase 1), and the plastids (LSU of RUBISCO). Strains in culture at the same time were used in mating studies to study reproductive isolation of species, and selected strains were examined for the production of the neurotoxin domoic acid (DA). Two new species, P. hasleana sp. nov. and P. fryxelliana sp. nov., are described based on morphological and molecular data. In all phylogenetic analyses, P. hasleana appeared as sister taxa to a clade comprising P. calliantha and P. mannii, whereas the position of P. fryxelliana was more uncertain. In the phylogenies of ITS, P. fryxelliana appeared to be most closely related to P. cf. turgidula. Morphologically, P. hasleana differed from most other species of the complex because of a lower density of fibulae, whereas P. fryxelliana had fewer sectors in the poroids and a higher poroid density than most of the other species. P. hasleana did not produce detectable levels of DA; P. fryxelliana was unfortunately not tested. In P. cuspidata, production of DA in offspring cultures varied from higher than the parent cultures to undetectable.