S. Poulsen et al., An Atlantic herring (Clupea harengus) size selection model for experimental gill nets used in the Sound (ICES Subdivision 23), CAN J FISH, 57(8), 2000, pp. 1551-1561
Citations number
29
Categorie Soggetti
Aquatic Sciences
Journal title
CANADIAN JOURNAL OF FISHERIES AND AQUATIC SCIENCES
Size selection investigations were performed in the Sound with experimental
, multipanel gill nets equipped with a broad range of mesh sizes targeting
Atlantic herring (Clupea harengus). Each of the 20 experimental fishery sur
veys covered the central Sound from Helsingor-Helsingborg (north) to Drogde
n-Klagshamn (south) during the autumn, winter, and spring periods from 1993
to 1998. There was high variability in catch sizes both between and within
surveys. The overall best fits, in terms of minimum total deviance across
all sets, were achieved using a unimodal normal scale model. Almost all sur
veys showed high between-set variation, which was accounted for when estima
ting the mean selectivity curves using a random effects model. The selectiv
ity curves fitted to individual sets were compared with those fitted to the
combined data sets. It was demonstrated that analysing pooled data sets re
sulted in overdispersion and bias in the selection parameters. Irregular ti
me series of the estimates of the selectivity parameters in the investigati
on period indicated negative autocorrelation with a seasonal pattern.