MEPS 189:241-250 (1999)  -  doi:10.3354/meps189241

Variability in Stage I egg production and settlement of plaice Pleuronectes platessa on the west side of the Isle of Man, Irish Sea

Richard D. M. Nash*, Audrey J. Geffen

School of Biological Sciences, University of Liverpool, Port Erin Marine Laboratory, Port Erin, Isle of Man IM9 6JA, United Kingdom

ABSTRACT: The variability in Stage I egg production and subsequent settlement of plaice Pleuronectes platessa L. on the west side of the Isle of Man, Irish Sea, was investigated over the period 1992 to 1998. This small spawning ground contributed approximately 0.6% of the total plaice egg production in the northern Irish Sea for 1995. The timing of peak egg production varied between years from approximately the middle of February to the end of March. The timing of peak egg production was related to the mean autumnal water temperature, with earlier spawning in warmer years. Egg production on the west side of the Isle of Man in 1995 was earlier than in the eastern Irish Sea, probably reflecting the slightly warmer water conditions in the central Irish Sea. The estimated Stage I egg production varied considerably between years, differing by a factor of 2.8 over all years. There was a positive relationship between the annual egg production and the numbers of individuals settling in Port Erin Bay. Interannual variation in abundance was greater at settlement than in either Stage I eggs or the size of the juvenile population in July. Higher inter-annual variability in the pelagic phase is dampened during the nursery ground phase.


KEY WORDS: Irish Sea · Plaice · Egg production · Settlement · Variability


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