Movements of 0‐group plaice Pleuronectes platessa L. as shown by latex tagging

Abstract

0-group plaice were caught in Red Wharf Bay, Anglesey, North Wales, tasged with coloured liquid latex, and released in the bay or, after transplantation, at a position on a sandbank 3.5 krn offshore. The pattern of movement shown by recaptures of plaice caught and released at the same position in the bay was one of extremely restricted movement of less than 0 5 km over several months, with only a slight interchange of fish between the sides of the bay and the centre. These restricted movements contrasted sharply with relatively long distances travelled by fish displaced to an unusual depth and position offshore and to a position at the other side of the bay 3 km away. In the first case a high proportion returned rapidly to the usual depth preference inshore and in the second a recapture pattcrn significantly different from that of control fish was demonstrated. Both results indicated a return to a preferred or familiar situation.

Size-selective predation of 0-group flatfishes on a Scottish coastal nursery ground

“…However, as Chambers & Leggett (1992) recognised, direct evidence of increased risk of mortality of the smaller members of a cohort is lacking, and has generally been inferred from mortality rates decreasing with size across species, or with development within a single species. Within juvenile flatfishes, density estimates and recapture data have shown that the mortality rate of smaller plaice was greater than that of larger sympatric individuals (Steele & Edwards 1970, Riley 1973. Yamashita et al (1994) showed that smaller individuals of hatcheryreared Japanese flounder Paralichthys olivaceus suffered higher mortality rates after release into the natural environment.…”

Field experiments on depth selection by juvenile plaice Pleuronectes platessa

“…Juvenile plaice also show 'homing' whereby they return to their original position when laterally displaced (Riley 1973, Burrows et al 2004) and on a larger scale, the ability of the adults to return to spawning and feeding grounds is well documented (e.g. Hunter et al 2003, Solmundsson et al 2005.…”

“…This fidelity to a particular depth can be compared with the horizontal site fidelity shown by young winter flounder Pseudopleuronectes americanus (Saucerman & Deegan 1991) and plaice (Riley 1973, Burrows et al 2004, in which individuals do not stray far alongshore. Juvenile plaice also show 'homing' whereby they return to their original position when laterally displaced (Riley 1973, Burrows et al 2004) and on a larger scale, the ability of the adults to return to spawning and feeding grounds is well documented (e.g.…”

The behavior of fishes in their acoustic environment

“…They found that the smaller species tended to be silent whereas the larger ones were vocal, and suggested that while the larger predatory species could afford to be heard, the smaller cryptic or pelagic ones that were often preyed upon could not. The use of acoustic clues in navigation was suggested by Riley (1973), but no reports exist on the response of fishes to acoustic gradients. Speculations will be presented in the next section.…”