engleski

Population study of the fan shell Pinna nobilis L. in Malo and Veliko Jezero of the Mljet National Park (Adriatic Sea)

Although previous studies have noted the presence of the bivalve Pinna nobilis in Mljet National Park, there is a lack of basic knowledge of this endangered species. The present study was initiated as a part of a long term investigation into the settlement density and growth of Pinna nobilis with the aim of getting a better understanding of this specie's population dynamics, as well as evaluating the efficiency of protection measures of P. nobilis in Mljet National Park. Settlement density, population structure, growth of tagged individuals and epibionts on Pinna nobilis were studied using SCUBA diving in 1998 and 2000 along four transects in Mljet lakes, Adriatic Sea. The average density of Pinna nobilis ranged from 0.24 ind/m2 in Malo Jezero to 0.04 ind/m2 in Veliko Jezero. Individuals measured in 1998 were significantly smaller than those measured in 2000. Growth of tagged individuals was dependant on their initial height. Decrease in density along some of the transects and the absence in 2000 of 24 tagged individuals is indicative of poaching. The results of the present study indicate recovery of Pinna nobilis population in Mljet lakes, but also provide evidence for the illegal removal of this protected species.

Pinna nobilis; bivalve; population study; Mljet National Park

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