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Life-history changes in exploited reef fishes on the east coast of South Africa

journal contribution
posted on 2023-05-16, 20:19 authored by Colin BuxtonColin Buxton
The impact of exploitation on various life-history characteristics of two sex changing, reef-dwelling sparid species was examined by comparing populations protected in a large marine reserve with those adjacent to the reserve. Like other sparids, Chrysoblephus laticeps and C. cristiceps grow slowly and are long lived, reaching ages of 17 and 21 years, respectively. No significant differences in the growth rate of C. laticeps were measured, but growth in C. cristiceps was significantly slower in the exploited population. Observed data showed that sex ratios outside the marine reserve were skewed towards the females, a result of size selective exploitation. Size at sex change was also significantly smaller for C. cristiceps in the exploited area, but not so for C. laticeps. This difference between the species was explained as a function of the size at recruitment into the fishery and the degree of protection afforded both large females and male fish. Considering the possibility that reproduction could be impaired as a result of changes in population structure, the tactic of protection through marine reserves is supported as a hedge against recruitment failure.

History

Publication title

Environmental Biology of Fishes

Volume

36

Pagination

47 - 63

ISSN

0378-1909

Department/School

Institute for Marine and Antarctic Studies

Publisher

Springer

Place of publication

Netherlands

Rights statement

The original publication is available at www.springerlink.com

Repository Status

  • Restricted

Socio-economic Objectives

Expanding knowledge in the environmental sciences

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