engleski

Biological parameters of megrim, Lepidorhombus whiffiagonis (Walbaum, 1792) (Osteichthyes: Scophthalmidae) from the eastern Adriatic Sea

Biological parameters of megrim collected in the eastern central Adriatic by commercial bottom-trawls were analysed. Monthly random samples, ranging from 9.0 to 35.9 cm in total length (TL) were collected from January to December 2006 ; with a total of 1118 specimens (538 males and 580 females) measured. The overall sex ratio was 1:1.07 in favour of females, and was close to the expected 1:1 sex ratio (p > 0.05). Allometric parameters of b values varied during the year ; positive allometric growth was noted from November to May while in other months isometric growth was observed. In the yearly sample, the b values for males (3.16), females (3.21) and sexes combined (3.18) showed that growth of megrim was positively allometric The GSI reached maximum values in January and minimum in June. The condition factor was lowest after spawning (June) and highest at the recovery phase (September). Otolith rings reading defined seven age classes, ranging from 1 to 7 years, including a very high proportion of individuals 2 years old. The von Bertalanffy growth parameters were, males: L¥ = 41.16, K = 0.152, to = - 1.39 years ; females L¥ = 44.76, K = 0.166, to = - 1.07 years ; sex combined: L¥ = 55.05, K = 0.104, to = - 1.61 years. The fishing mortality (F = 0.60) and exploitation rate (E = 0.61), revealed a high fishing pressure on the stock in studied area.

length-weight relationships; gonadosomatic index; condition; mortality; Lepidorhombus whiffiagonis

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