Age, growth and mortality of European pilchard, Sardina pilchardus in Edremit Bay (northern Aegean Sea, Turkey)

Erdogan Z., Torku-Koç H., Gicili S., Ulunehir G.

Date de parution: juin 2010
Volume: 34
Number: 2
Pagination: 185–193
Résumé

Age, growth and mortality of the European pilchard, Sardina pilchardus (Walbaum, 1792) were determined from 503 specimens collected on the northwestern Aegean coast of Turkey from November 2005 to October 2006. Fork length ranged from 8.7 to 14.3 cm while weight varied between 7.05 and 32.66 g. The von Bertalanffy growth equation was fitted on the basis of mean length-at-age data resulting in parameter values of L∞ = 15.23 cm, K = 0.47, to = -1.21. The b value for males (b = 2.455) was somewhat lower than that for females (b = 2.642), showing negative allometry. The oldest male and female were estimated to be three years old. Total (Z), natural (M) mortality, fishing (F) mortality were 0.94, 0.64, 0.30 per year, respectively. The exploitation ratio E = 0.32 indicated that the population was slightly exploited. The sex ratio was skewed in favour of females (1:1.31). The monthly values of gonadosomatic index (GSI) of females indicated that spawning occurred mainly between September and May with a peak in February.
 

Mots-clés: Age - Clupeidae - Edremit Bay - Gonadosomatic index - Growth - MED - Mortality - Sardina pilchardus
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