Population Structure, Growth, Mortality and Fecundity of Palaemon adspersus (Rathke 1837; Decapoda: Palaemonidae) in the Parila Lagoon (Croatia, SE Adriatic Sea) with Notes on the Population Management

Abstract

Baltic prawn, Palaemon adspersus population from the Parila lagoon (SE Adriatic Sea, Croatia) was studied between 2010-2011. Specimens were collected monthly in order to determine population structure, growth, mortality and reproduction of this important decapods species. The von Bertalanffy growth function parameters were found L∞=58.98 mm, K=0.975 year−1 and to=-0.0046 years for males and L∞=72.45 mm, K=1.058 year−1 and to=-0.0005 years for females. Growth performance (Φ') for females was higher (3.229) than that of males (3.121). Maximum calculated age was 3.07 and 2.83 years for males and females, respectively, while total mortality was estimated as 3.72 per year for males and 3.79 per year for females. The females carried on average 2157 eyed eggs per 1g of total body weight, but exhibited a high variability of fecundity. The results show overexploitation of the resource and therefore management rules based on the precautionary approach are proposed. These rules are based on the limitation of the fishing effort and the establishment of 'no-take' periods during the year as well as the proposal of two biological reference points based on a minimum landing size related to the size at- maturity and the fishing mortality at Maximum Sustainable Yield.