Publication Abstract

Seasonal migrations of plaice (Pleuronectesplatessa) through the Dover Strait

G.P. Arnold and J.D. Metcalfe

Analysisof paired-haul mid-water trawling experiments conducted in the five months November toMarch during the years 1985 and 1988 revealed the seasonal pattern of migration of plaice (Pleuronectesplatessa L.) moving through the Dover Strait between the Southern Bight of the NorthSea and the English Channel. Mid-water catches of maturing fish were highest onsouth-going tides prior to peak spawning (late January), while catches of spentfish, were highest on north-going tides after peak spawning. Detailed analysis ofthe catch data provided evidence that males complete their pre-spawning migration earlier,and their post-spawning migration later, than female fish and consequently spend more timeon the spawning ground. Catches of immature female fish indicated a migration southfollowing that of the mature fish. This "dummy run" may be a method by whichimmature plaice use the presence of high densities of mature and spawning fish to learnthe location of the spawning ground. The analysis also indicated that differences in catchrates between day and night are unlikely to be the result of gear avoidance by day. Theresults confirm that selective tidal-stream transport is a key migratory mechanism forplaice in areas of fast tidal streams on the European continental shelf.

Reference:

G.P. Arnold and J.D. Metcalfe, 1996. Seasonal migrations of plaice (Pleuronectesplatessa) through the Dover Strait. Marine Biology, 127: 151-160.