New Zealand Journal of Marine and Freshwater Research abstracts
Reproduction of the sea urchin Evechinus chloroticus (Echinodermata: Echinoidea) in a New Zealand fiord
Miles D. Lamare
Paul E. Brewin
Mike F. Barker
Stephen R. Wing
Department of Marine Science
University of Otago
P.O. Box 56
Dunedin 9015, New Zealand
email: miles.lamare@stonebow.otago.ac.nz
Abstract The reproductive cycle of Evechinus chloroticus (Val.) was examined at three (outer, mid, and inner) sites in Doubtful Sound, Fiordland over a 3-year period. We found that sea urchins from all three populations had an annual gametogenic cycle, the timing of which was temporally and spatially consistent. Inter-individual variation in the gametogenic cycle was noted within each population, however, initiation of gametogenesis was generally synchronous among males and females and among sites, occurring in May/June. Strong asynchrony in gamete maturation was observed in Deep Cove, occurring in males 4-5 months earlier than females. Spawning occurred in December at the inner and mid fiord sites, while occurring in January at the outer fiord site. Reproductive potential (maximum gonad index) and output (weight of gametes released/g of animal/year) varied spatially and temporally, where there was a consistent decreasing trend in reproductive potential and output with increasing distance away from the fiord entrance. Spatial variation in reproductive output may be associated, in part, with the strong ecological gradient found in Doubtful Sound, where there is a reported decrease in macrophyte biomass and cover towards the fiord headwaters. The implications of spatial differences in gonad production with respect to the population biology and fisheries management of E. chloroticus in the fiords are discussed.
Keywords Evechinus chloroticus; reproduction; Fiordland; benthic productivity; sea urchin fishery
M01090 Received 28 November 2001; accepted 9 May 2002; published 14 November
New Zealand Journal of Marine and Freshwater Research, 2002, Vol. 36: 719-732
0028-8330/02/3604-0719 $7.00 © The Royal Society of New Zealand 2002
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