FACTORS AFFECTING THE ANNUAL ABUNDANCE AND REGIONAL DISTRIBUTION OF ENGLISH INSHORE DEMERSAL FISH POPULATIONS - 1973 TO 1995

Citation
Si. Rogers et Rs. Millner, FACTORS AFFECTING THE ANNUAL ABUNDANCE AND REGIONAL DISTRIBUTION OF ENGLISH INSHORE DEMERSAL FISH POPULATIONS - 1973 TO 1995, ICES journal of marine science, 53(6), 1996, pp. 1094-1112
Citations number
35
Categorie Soggetti
Fisheries,"Marine & Freshwater Biology",Oceanografhy
ISSN journal
10543139
Volume
53
Issue
6
Year of publication
1996
Pages
1094 - 1112
Database
ISI
SICI code
1054-3139(1996)53:6<1094:FATAAA>2.0.ZU;2-9
Abstract
The 2 m beam trawl and 1.5 m push net were used to sample the small ep ibenthic fish assemblage during September on the east and south coasts of England. Fishing stations were distributed along the entire coast within four depth bands to 20 m. A total of 104 species were caught be tween 1973 and 1995, and these included infrequent Lusitanean species such as the big-scale sand-smelt (Atherina boyeri), and the undulate r ay (Raja undulata). and infrequent boreal species such as the Norway h addock (Sebastes viviparus). Fifty-four taxa were selected as represen tative of the small, demersal inshore fish community that would be mos t vulnerable to capture by the two sampling gears, and were used in su bsequent analyses of community structure. The north-east coast assembl age was the least diverse (H'=1.58) and least even (J'=0.47). II also supported the least number of species (55), and the variation in catch of the only dominant genus, Pomatoschistus spp., was partly responsib le for large year-to-year variations in diversity and in the total pop ulation abundance of selected demersal species. On the east and south- east coasts, both diversity (H'=1.78 and 1.93) and evenness (J'=0.50 a nd 0.51) were greater than in the north, as a result of larger numbers of species available to the gears, and several species with relativel y high catch density, such as Pomatoschistus spp., dab (Limanda limand a), solenette (Buglossidium luteum), and dragonet (Callionymidae). As a result, the fish assemblages of these coasts showed lower inter-annu al variation in evenness and diversity. Trends in mean catch density o f some species were correlated with the mean surface water temperature and salinity, especially for species which were near the edge of thei r normal geographic distribution in the southern North Sea. In additio n, mean surface water temperatures were positively correlated with the total number of Lusitanean species on the south coast. These data pro vide evidence that during a period of more than 20 years, hydrographic factors have not only affected species abundance, but, at low density , also their presence or absence in catches. (C) 1996 International Co uncil for the Exploration of the Sea