ANNUAL 211(D) GRANT REPORT 1977-1978 (RESOURCE ASSESSMENT SUBPROJECT)

SUBPROJECT OBJECTIVE WAS TO TEST SYSTEMS OF DATA COLLECTION AND ANALYSIS USEFUL IN MANAGEMENT OF TROPICAL, MARINE FISHERY RESOURCES AND THE DEVELOPMENT OF ARTISAN FISHERIES. PROJECT TARGETS ARE ON SCHEDULE. THE BEVERTON-HOLT YIELD MODEL HAS BEEN ADOPTED FOR RESOURCE ASSESSMENT. THE 2 METHODS FOR ESTIMATING THE GROWTH AND MORTALITY RATE OF FISH ARE ANALYSIS OF LENGTH-FREQUENCY DATA AND A TAG AND RECAPTURE STUDY. WITH COOPERATION OF COSTA RICA"S MINISTRY OF AGRICULTURE (MOA) OVER 40, 000 INDIVIDUAL LENGTH MEASUREMENTS WERE COLLECTED. ASSISTANCE FROM MOA AND GOVERMNMENT OF COSTA RICAN BIOLOGISTS ALSO RESULTED IN THE TAGGING OF 2, 200 FISH COMPRISING 20 SPECIES. SIX OF THESE SPECIES, OF COMMERCIAL IMPORTANCE, WERE TAGGED IN SUFFICIENT QUANTITIES TO PERMIT PARAMETER ESTIMATION. DATA CONCERNING CATCH-PER-UNIT EFFORT AND LENGTH-FREQUENCY INFORMATION ARE BEING ANALYZED AND RESULTS WILL BE SUBMITTED TO THE MOA IN 10/78. THREE REPORTS GENERATED BY SUBPROJECT ACTIVITIES HAVE EITHER BEEN PRESENTED AT THE ANNUAL GULF & CARRIBBEAN FISHERIES INSTITUTE OR WILL SOON APPEAR IN SCIENTIFIC PUBLICATIONS. ALTHOUGH TAGGED FISH HAVE BEEN RETURNED, THE LOW RATE OF RETURN (41 FISH) HAS BEEN DISAPPOINTING. EVALUATOR FEELS RETURN RATES COULD BE INCREASED IF REWARDS PAID FOR TAGGED FISH WERE INCREASED AND FISHERMEN WERE BETTER EDUCATED AS TO THE IMPORTANCE OF THEIR COOPERATION. CAGE EXPERIMENTS ALSO PROVED DISAPPOINTING DUE TO ADVERSE WORKING CONDITIONS AND THE SCANTY AMOUNT OF DATA COLLECTED. IT IS BEING RECOMMENDED THAT DURING 1978-79: 1)TAG RETURNS BE STUDIED TO DETERMINE THEIR EFFECTIVENESS IN DETERMINING A YIELD MODEL AND STOCK MANAGEMENT MODEL; 2)A TAGGING AND RECAPTURE HANDBOOK BE CONSIDERED FOR PUBLICATION; AND 3)LENGTH-WEIGHT, AND TAG AND RECAPTURE STUDIES BE CONTINUED. REPORT ALSO EVALUATES 6 OTHER SUBPROJECTS AND URI PERFORMANCE.