NOTES 



MASS MORTALITY OF SCIAENID FISHES IN 

 THE GULF OF NICOYA, COSTA RICA' 



An unusual fish mortality, nearly specific for the 

 family Sciaenidae (corbinas, croakers, drums), is 

 reported for the Gulf of Nicoya, Costa Rica. The gulf 

 is a large, estuarine embayment located on the 

 Pacific coast of Costa Rica (Fig. 1). Its waters pro- 

 vide roughly 50% of Costa Rican commercial finfish 

 landings, with sciaenids accounting for about 43% 



'CIMAR Contribution No. 138. 



of the artisanal catch, or about 2,700 metric tons 

 per year (Araya 1984; Ministerio de Agricultura y 

 Ganaderia unpubl. data 1985). 



Initial observations of the mortality by residents 

 of the inner gulf were made in late September 1985. 

 By mid-October, extensive sciaenid mortalities had 

 been reported throughout the inner gulf northwest 

 of Puntarenas and Playa Naranjo, and observed by 

 us in the middle of the gulf between Puntarenas and 

 Isla Chira (Fig. 1). Local fishermen noted that fishes 

 were not affected in the gulf oceanward of Punta- 

 renas. They also noted that members of the corbina 



Pacific 

 Ocean 



20 Km 



Figure 1.— Gulf of Nicoya, Costa Rica. Shading indicates suspected extent of sciaenid 



mortality. 



FISHERY BULLETIN, US. 87:363-365, 1989, 



363 



