The Impact of Commercial Exploitation on Sawfish and Shark Populations in Lake Nicaragua

Autor: Thomas B. Thorson
Rok vydání: 1982
Předmět:
Zdroj: Fisheries. 7:2-10
ISSN: 1548-8446
0363-2415
DOI: 10.1577/1548-8446(1982)007<0002:tioceo>2.0.co;2
Popis: The Lake Nicaragua Rio San Juan System harbors two classical examples of freshwater adaptation by elasmobranchs, the bull shark, Carcharhinus leucas, and the largetooth sawfish, Pristis perotteti. The bull shark is heavily concentrated around the river mouth and reproduces along the coast. The sparser population in the lake is recruited almost entirely through upstream movements from the lower river. Relatively heavy, year round commercial fishing around the river mouth since the late 1960's has sharply reduced the shark population in the lake. Since the shark fishery is primarily in Costa Rican waters, control and management can be effected only by a cooperative agreement between Costa Rica and Nicaragua, which has not yet been reached. The sawfish lives and reproduces primarily in the lake, where until 1970 a heavy concentration occurred, with relatively few being found in the lower river. Since 1970 heavy commercial fishing for sawfish has been carried on in Lake Nicaragua. A sharp reduction i...
Databáze: OpenAIRE
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