J. Moll. Stud. (1987), 53, 213-222
© The Malacological Society of London 1987
research-article |
THE AGE AND SIZE STRUCTURE OF SOME NORTHERN POPULATIONS OF THE TROCHID GASTROPOD MONODONTA LINEATA
NERC Rocky Shore Surveillance Group, University of Newcastle upon Tyne, Dove Marine Laboratory,Cullercoats, North Shields, Tyne & Wear, NE30 4PZ
Northern geographic limits of the distribution of the trochid gastropod Monodonta lineata are reached in the south and west of the British Isles. Populations in S.W. England and Wales were sampled annually between 1978 and 1984, and the success of each year class was assessed (approximately 18 months after larval settlement). During this period, recruitment failure was infrequent and its effects were generally offset by the species' longevity. In 1986 animals from 16 populations in S.W. England and N. France were aged, confirming that at the majority of near-limit sites Monodonta recruits frequently. This is in sharp contrast with other trochids in which near-limit populations often lack several year classes.
(Received 15 December 1986;
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