Are there really less sharks in Costa Rican waters? One way to know is to compare relative abundance of sharks in the fishery throughout time. Unfortunately, long term reliable information on shark relative abundance in the region is largely unknown. Since 1999, PRETOMA has developed an observer program on board commercial longliners from Playas del Coco belonging to Papagayo Seafoods S.A., a company based in Playa del Coco, Guanacaste, Costa Rica 's northwestern province.

Our research shows a dramatic decline in shark relative abundance in the longline fishery from 1991 to 2001. A probability test showed a decline of 60%. From 2001 to 2003 no further decline was detected, because of which we concluded that in the Exclusive Economic Zone of Costa Rica sharks had hit rock bottom.

Arauz, R., Y. Cohen, J. Ballestero, A. Bolaños, M. Pérez. 2004. Decline of Shark Populations in the Exclusive Economic Zone of Costa Rica. International Symposium on Marine Biological Indicators for Fisheries Management. UNESCO, FAO. Paris , France . March, 2004.

More results with information dating back to 1995 were presented during a Shark Symposium held in Costa Rica in February 2006, in the framework of the National Plan of Action Sharks.

Randall Arauz, Andrés López , Jorge Ballestero & Allan Bolaños. 2006. Estimación de la abundancia relativa de tiburones en la Zona Económica Exclusiva de Costa Rica a partir de observadores a bordo de la flota de palangre de Playas del Coco, Guanacaste, Costa Rica.