Aspects of the population dynamics of Liza klunzingeri in the Kuwait Bay

Dadzie S., Manyala J.O., Abou-Seedo F.S.

Date de parution: février 2005
Volume: 29
Number: 1
Pagination: 013-020
Editeur: Société Française d’Ichtyologie

The growth characteristics of Liza klunzingeri (Day, 1888) in Kuwait Bay were evaluated based on data collected from 1982 to 1999. Length-based stock assessment showed an asymptotic length (L∞) of 24.8 cm TL and growth curvature (K) of 0.46 yr-1. The growth of L. klunzingeri follows the seasonally oscillating VBGF typical of temperate species with both an amplitude (C) and winter point (WP) of 0.95. The total mortality coefficient (Z) was estimated to be 4.61 yr-1 for raw data and 4.27 yr-1 after accounting for gear selection. Logistic selection model showed that 25% of fish of 3.5 cm TL, 50% of specimens reaching 4.8 cm TL and 75% of all specimens of 6.1 cm TL encountering the gear are retained. From the raw data, two recruitment peaks in a year seem to be evident, a minor one in May (13.5%) and a major one in September (17.5%). However, after accounting for gear selection, the recruitment strength was confined to September (37.8%). The current exploitation rate of 0.75 is above the optimum (0.239), the maximum (0.373) and the economic (0.305) yield indices. It is estimated that the Maximum Economic Yield (MEY) would be obtained when the average weight of fish caught is 0.6 of the maximum weight or 60% of the asymptotic weight. The traps used in the fishery seem to have adverse effects on recruitment and could be the cause of depression in the stocks. Management implications are discussed in the light of growth, mortality, recruitment and exploitation of Liza klunzingeri in the Kuwait Bay.

Mots-clés: Gear selectivity - Growth - Kuwait Bay - Liza klunzingeri - Mortality - Mugilidae - Recruitments - Yield indices
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