Benthic Boundary Layer Macrofauna of Browns Bank, Northwest Atlantic, as Potential Prey of Juvenile Benthic Fish

1992 ◽  
Vol 49 (1) ◽  
pp. 91-98 ◽  
Author(s):  
D. J. Wildish ◽  
A. J. Wilson ◽  
B. Frost
Keyword(s):  
Boundary Layer ◽  
Fish Larvae ◽  
Quantitative Description ◽  
Melanogrammus Aeglefinus ◽  
Benthic Boundary Layer ◽  
Northwest Atlantic ◽  
Sediment Flow ◽  
Sediment Interface ◽  
Haddock Melanogrammus Aeglefinus

A first quantitative description is provided of the drifting or swimming macrofauna present within the benthic boundary layer (BBL) over the hard sediments of Browns Bank in the northwest Atlantic. Major categories of identified animals include drift epi- or infauna, zooplankters, fish larvae and eggs, and suprabenthic animals. Suprabenthic amphipods were good indicators of the type of sediment/flow environment that they were associated with. Although zooplanktonic copepods were by far the most abundant and suprabenthos the most diverse group of the BBL macrofauna, they appear to be ignored as a source of food by juvenile haddock (Melanogrammus aeglefinus), which are known to feed on prey classified herein either as in situ, or drifted, epi- or infauna. Unfortunately, the BBL sled used in our study could not sample animals at < 33 cm from the sediment–water interface. Our results imply that juvenile haddock feed either directly on animals living in, or at the sediment interface, or on drifting animals present within the BBL at heights < 33 cm above the bottom

Recruitment to Northwest Atlantic Cod (Gadus morhua) and Haddock (Melanogrammus aeglefinus) Stocks: Influence of Stock Size and Climate

1987 ◽  
Vol 44 (1) ◽  
pp. 26-39 ◽  
Author(s):  
J. Anthony Koslow ◽  
Keith R. Thompson ◽  
William Silvert
Keyword(s):  
Large Scale ◽  
Gadus Morhua ◽  
Reproductive Output ◽  
Atlantic Cod ◽  
Low Frequency ◽  
Melanogrammus Aeglefinus ◽  
Northwest Atlantic ◽  
Biological Variables ◽  
Low Frequency Variability ◽  
Haddock Melanogrammus Aeglefinus

Year-class success of both Atlantic cod (Gadus morhua) and haddock (Melanogrammus aeglefinus) stocks in the northwest Atlantic exhibits large-scale coherence and low-frequency variability with apparent periodicities of 10–20 yr. Several physical and biological variables in the region exhibit similar large-scale coherence and apparent periodicity. Multiple regression analysis indicates that year-class success in northwest Atlantic cod stocks tends to be associated with large-scale meteorological patterns and offshore winds. Recruitment to most haddock stocks from the Scotian Shelf to Georges Bank is negatively associated with abundance of 0-group mackerel, which may be due to predation over winter and/or to a combination of environmental features including sea-surface temperature, large-scale atmospheric pressure systems, and freshwater outflows. Statistical analyses often did not define a unique set of variables that best predicted fishery recruitment due to widespread intercorrelations among environmental processes and the likelihood that not all relevant processes entered directly into the analyses. There is little evidence that stock reproductive output during the study period was significantly related to year-class success.

Phanerozoic development of tiering in soft substrata suspension-feeding communities

Paleobiology ◽  
1986 ◽  
Vol 12 (4) ◽  
pp. 400-420 ◽  
Author(s):  
David J. Bottjer ◽  
William I. Ausich
Keyword(s):  
Boundary Layer ◽  
Benthic Boundary Layer ◽  
Suspension Feeding ◽  
Velocity Gradients ◽  
Phylogenetic Constraints ◽  
Recent Brachiopods ◽  
Shallow Subtidal ◽  
The Vertical Distribution ◽  
Sediment Interface

Tiering is the vertical distribution of organisms within the benthic boundary layer. Primary tierers are suspension-feeding organisms with a body or burrow that intersects the seafloor. Secondary tierers are suspension-feeders that maintain positions above or below the sediment-water interface as either epizoans on primary tierers and plants or by living in the burrows of primary tierers. Different primary tierers from soft substrata, nonreef, shallow subtidal shelf and epicontinental sea settings have had different tiering histories, resulting largely from contrasting constructional and phylogenetic constraints. Primary colonial tierers generally occupied lower epifaunal tiers during the Paleozoic and Mesozoic, but since the Cretaceous they have been dominant in the highest tier (+ 20 to +50 cm). Primary echinoderm tierers have been almost exclusively epifaunal, and from the Paleozoic through the Jurassic they were present throughout the epifaunal tiered structure. Although primary bivalve tierers have been both epifaunal and infaunal, they have occupied only lower epifaunal tiers, whereas they have adapted to all levels of the infaunal tiering structure, particularly from the late Paleozoic through the Recent. Brachiopods have lived primarily in tiers directly above or below the water-sediment interface and have not contributed significantly to tiering complexity.Of the numerous physical and biotic processes and constraints that affect shallow marine benthos, a few have contributed more significantly to changes in tiering patterns. Trends for increasing body size could have accounted for most of the development of tiering complexity up to +50 cm and down to –12 cm. Development of tiering above +50 cm could have been due to processes which would have yielded greater feeding capability, such as competitive interactions for a place from which to feed or adaptations to velocity gradients in the hydrodynamic boundary layer. The most significant process for development of infauanl tiering below –12 cm appears to have been as an adaptive response for predator avoidance.Unlike infaunal tiering, which never declined after it developed, epifaunal tiering has undergone a general reduction twice. Reduction in epifaunal tiering at the end of the Paleozoic appears to have been the result of the mass extinction at this time, whereas long-term biotic processes seem to have been more important for the tiering decline at the end of the Mesozoic. Tiering structure through the Phanerozoic was thus produced through interactions of a number of physical and biotic factors, tempered by constructional and phylogenetic constraints of each primary tierer group.

Analysis of Haddock (Melanogrammus aeglefinus) sounds recorded in the Northwest Atlantic

2018 ◽  
Vol 143 (3) ◽  
pp. 1899-1899
Author(s):  
Xavier Mouy ◽  
Rodney A. Rountree ◽  
Katie A. Burchard ◽  
Francis Juanes ◽  
Stan E. Dosso
Keyword(s):  
Melanogrammus Aeglefinus ◽  
Northwest Atlantic ◽  
Haddock Melanogrammus Aeglefinus

Microsatellite evaluation of haddock (Melanogrammus aeglefinus) stocks in the northwest Atlantic Ocean

2001 ◽  
Vol 58 (5) ◽  
pp. 982-990 ◽  
Author(s):  
Christopher Lage ◽  
Maureen Purcell ◽  
Michael Fogarty ◽  
Irv Kornfield
Keyword(s):  
Melanogrammus Aeglefinus ◽  
Georges Bank ◽  
Effective Number ◽  
Scotian Shelf ◽  
Genetic Structuring ◽  
Northwest Atlantic ◽  
Spawning Aggregations ◽  
The Impact ◽  
Significant Genetic Divergence ◽  
Haddock Melanogrammus Aeglefinus

The goal of this study was to gain insight about the impact of intensive fishing on a single haddock (Melanogrammus aeglefinus) stock, and examine the genetic structuring of spatially discrete spawning aggregations in the northwest Atlantic. We analyzed genetic change at four microsatellite loci for Georges Bank haddock over a 40-year time span in which significant changes in demographics and abundances have occurred in the population. Allelic diversities have changed little, indicating that, although the commercial fishery has collapsed, stock sizes have remained large enough to insulate against major reductions in genetic variation due to drift. Results indicate significant genetic divergence among decadally separated samples. Potential causes for these differences include admixture from other spawning regions, fluctuations in the effective number of spawners contributing to a single spawning event, drift, or a combination of these. Examination of discrete spawning aggregations from Georges Bank, Browns Bank, the Scotian Shelf, and Nantucket Shoals indicated significant differences among stocks. Genetic distance based measures supported the clustering of Scotian Shelf, Browns Bank, and Georges Bank haddock to the exclusion of Nantucket Shoals haddock. Haddock spawning on Nantucket Shoals may be genetically discrete from other haddock populations in the northwest Atlantic.

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