New Zealand Journal of Marine and Freshwater Research abstracts
Genetic differentiation in the New Zealand sea urchin Evechinus chloroticus
(Echinodermata: Echinoidea)
P. V. MLADENOV
Department of Marine Science
University of Otago
P. O. Box 56, Dunedin
New Zealand
R. M. ALLIBONE1*
G. P. WALLIS1,2
1Department of Zoology
2Centre for Gene Research
University of Otago
Dunedin, New Zealand
*Present address: Natiuonal Institute of Water and Atmospheric Research Ltd, P.
O. Box 11 115, Hamilton, New Zealand.
Abstract Genetic differentiation in the New Zealand sea
urchin Evechinus chloroticus (Valenciennes) was studied by examining
individuals collected from six widely separated (250-2200 km apart) sites from
around New Zealand for genetic variation at five polymorphic enzyme loci.
Despite the large geographic separations, values of Nei's unbiased genetic
distance, D (0-0.019) and standardised genetic variation among
populations, FST (0.01-0.02) were small. This indicates high levels of
gene flow among populations. However, one population sampled in a fiord in
south-western New Zealand was genetically differentiated from the others,
although the scale of differentiation was not large (D = 0.011-0.019).
These findings indicate: (1) that the long-lived planktotrophic larva of E.
chloroticus provides this species with considerable dispersal ability
throughout its range; and (2) that this is little affected by oceanographic
features peculiar to its range, such as the Subtropical Convergence or the
southward flowing East Cape Current. The slight differentiation of the fiord
population probably results from restricted larval dispersal into and out of
the fiord. In terms of management of the E. chloroticus fishery, the
results provide no evidence for discrete stocks, with the possible exception of
Fiordland. It is prudent to manage the fiord populations conservatively until
they are better studied.
Keywords sea urchin; isozymes; genetic variation; gene flow;
larval dispersal; fishery management
New Zealand Journal of Marine and Freshwater Research, 1997, Vol. 31:
261-269
0028-8330/97/3102-0261 $7.00/0 (c) The Royal Society of New Zealand
1997
PDF file of entire paper: medium quality (706K); (scanned from paper original: notes about this process)
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