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
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