E. Bachiller, X. Irigoien
ICES Journal of Marine Science, 70, pp. 232-243, (2013)
Allometric relationships, Bay of Biscay, Predator-prey size ratio, Small pelagic fish, Stomach weight, Trophic-niche breadth
The body size of fish is an important factor in determining their
biology and ecology, as predators eat prey smaller than
themselves. Predator mouth size restricts the
availability of possible prey. In this paper we provide the allometric
of eight common, small pelagic fish species in the
Bay of Biscay. In addition, we describe the predator-prey size ratios
different species, and we determine changes in
their ratio-based trophic-niche breadth with increasing body size.
suggest that gape size does not totally determine
the predator-prey size ratio distribution, but predators use the entire
available prey size range, including the smallest.
As they grow they simply incorporate larger prey as their increased gape
size permits. Accordingly, a large degree of
overlap was found in the diet composition in terms of size and
ratios, even between fish of different sizes. Of
the species studied, only horse mackerels seem to be clearly specialized
in relatively large prey.