Integrated Sustainable Fisheries Management for Pearl Mullet of Lake Van, Turkey

Abstract

The pearl mullet is the sole endemic fish species that can survive in the salty and alkaline waters of Lake Van. Covering an area of 3712 km2, with mean depth of 171 m, maximum depth of 451 m, and 1648 m above sea level, this is Turkey’s largest lake. Its waters are extremely alkaline and salty. Due to the nature of these waters, it is characterized as a “soda lake”. Researchers have reported a pH level of approximately 9.8, with saltiness at 0.19% (Kempe et al., 1978). The lake’s biological diversity is significantly different from both fresh and salt waters. Its phytoplankton resources consist of 103 species belonging to the Diatome, Bacteriophyta, Cynophyta, Chlorophyta, Flagellate and Phaeophyta groups, and its zooplankton resources include 36 species from the Rotatoria, Cladocera and Copepod groups (Selcuk 1992). The pearl mullet (Chalcalburnus tarichi, Pallas 1811), a species belonging to the Cyprinidae family, is the only fish that can survive in Lake Van. The pearl mullet is a migrating species. Although it generally lives in the lake, it immigrates to the surrounding freshwater rivers for reproduction purposes and returns to Lake Van after the reproduction period. The earliest available information on the fishery practices related to the pearl mullet comes from travelers that visited the Lake Van region. Among them, Evliya Celebi (17th century) provides the most detailed account. Having arrived to Van with a general, Melik Ahmet Pasha, Celebi speaks of the lake as the “Van Sea”, stating that a certain species of fish exist in these waters that migrate annually to the Bendi Mahi River creek for a month as a flock. He goes on to explain that the fish are captured on their way back to the lake by the provincial treasurer, salted and then taken to the Iran, Nagorno Karabakh, and Azerbaijan area to be sold. He says 900 loads of silver coins are thus collected for the treasury each year and this income is then distributed among the soldiers serving in the fortress around the lake (E. Celebi, 17th Century). The first detailed study on the biology of the pearl mullet was carried out by Akgul (1980); further research was conducted by DanulatS Cetinkaya et al’s (1995) on some selectivity characteristics of nets used for pearl mullet fishing; Sari’s (1997a) research which presents the basics of current fishery management practices and proposes an alternative model based on estimated pearl mullet stock quantities; Sari’s study (1997b) on mesh selectivity for pearl mullet fishery; Sari