Biodiversity and species-environment relationships of the demersal fish assemblage at the Great Meteor Seamount (subtropical NE Atlantic), sampled by different trawls.

Fock, H., Uiblein, F., Köster, Friedrich W. and von Westernhagen, H. (2002) Biodiversity and species-environment relationships of the demersal fish assemblage at the Great Meteor Seamount (subtropical NE Atlantic), sampled by different trawls. Marine Biology, 141 . pp. 185-199. DOI 10.1007/s00227-002-0804-y.

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Abstract

Quantitative data collected with different bottom trawls at the Great Meteor Seamount (subtropical NE Atlantic, 30°N; 28.5°W) in 1967, 1970 and 1998 are compared. Bootstrap estimates of total catch per unit effort increased from 6.96 and 10.8 ind. m–1 h–1 in 1967 and 1970, respectively, to 583.98 ind. m–1 h–1 in 1998. Gear effects and an effect of gear over time accounted for 47.1% and 20% of species variability. Further significant factors were time of day and habitat, while season was not significant. A total of 43 species was collected. Including supplementary species information, a grand total of 46 species was found associated with the Great Meteor Seamount. Diversity was higher in 1967 and 1970 (Shannon's diversity: H′=2.5 and 1.6) than in 1998 (H′=0.9). Species–environment relationships are discussed in terms of a sound-scattering layer–interception hypothesis, i.e. utilisation of prey from a diurnally moving sound-scattering layer for the bentho-pelagic community. This is probably augmented by concentration effects in a circular current around the seamount (Taylor-column). Long-term changes are discussed with respect to a decrease in biodiversity due to considerable increases in Macroramphosus scolopax and Capros aper. In 1998, the increase of abundance of Trachurus picturatus and the respective decreases for genuine benthic species were likely to have been caused by a change of gear.

Document Type: Article
Keywords: Fish Assemblage, Total Catch, Benthic Species, Unit Effort, Bottom Trawl
Research affiliation: OceanRep > GEOMAR > FB3 Marine Ecology > FB3-EV Marine Evolutionary Ecology
Refereed: Yes
Open Access Journal?: No
DOI etc.: 10.1007/s00227-002-0804-y
ISSN: 0025-3162
Date Deposited: 18 Feb 2008 17:25
Last Modified: 07 Jun 2018 09:30
URI: http://oceanrep.geomar.de/id/eprint/5452

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