Abstract. — The catch and effort 

 of reef fisheries in seven areas of 

 Belize and in six of south Jamaica 

 were intensively surveyed to pro- 

 vide data for area-based surplus- 

 production models (SPM) to man- 

 age these fisheries. Data were nor- 

 malized to area of productive habi- 

 tat. SPM's could not be defined for 

 the Belizean or Jamaican data 

 treated separately because the 

 slopes of the relationships between 

 catch per unit of effort and effort 

 were nonsignificant and positive. 

 This appeared to be due 1 ) to vio- 

 lations of the model's assumptions 

 (catch composition was heteroge- 

 neous because fishermen target 

 spawning aggregations and migra- 

 tory fishes at particular sites) and 

 2) to possible differences in commu- 

 nity composition among areas (the 

 communities were not at equilib- 

 rium and productivity possibly dif- 

 fered among sites). Other assump- 

 tions had been violated by previ- 

 ous area-based SPM's so that the 

 level of exploitation on the south 

 Jamaican shelf has been seriously 

 underestimated in recent decades. 

 Although a SPM could be defined 

 for the combined Jamaica-Belize 

 data set, we conclude that these 

 models should be used with caution 

 in reef fisheries management be- 

 cause underlying assumptions are 

 likely to be seriously violated. The 

 surveys indicate, however, that lev- 

 els of catch per unit of effort, catch, 

 and effort in the south Jamaican 

 reef fishery are significantly lower 

 than those of 10 years ago. Deple- 

 tion of a wide range of fish groups 

 has apparently led to a decline in 

 the equilibrium productivity of the 

 fishery. 



Catch and effort analysis of the 

 reef fisheries of Jamaica and Belize 



Julian A. Koslow 



CSIRO Division of Fisheries, Marine Laboratories 

 GPO Box 1538, Hobart, Tasmania 7001 Australia 



Karl Aiken 



Zoology Department, University of the West Indies 

 Kingston, Jamaica 



Stephanie Auil 



Fisheries Unit, Princess Margaret Drive 

 Belize City, Belize 



Antoinette Clementson 



Zoology Department, University of the West Indies 

 Kingston, Jamaica 



Manuscript accepted 5 May 1994. 

 Fishery Bulletin 92:737-747. 



Tropical coral reef fisheries are typi- 

 cally small scale but highly com- 

 plex, artisanal multispecies fisher- 

 ies. They are often overexploited 

 (Munro, 1983; Koslow et al., 1988; 

 Russ, 1991) but are rarely managed 

 with conventional fishery methods 

 (see Johannes [1978] on traditional 

 management of reef fisheries). Con- 

 ventional fishery models are not 

 particularly suitable for complex, 

 multispecies fisheries, and the req- 

 uisite data, because of the highly 

 decentralized landing and market- 

 ing systems typical of these fisher- 

 ies, is often difficult to obtain. The 

 regions supporting these fisheries 

 often lack the technical and finan- 

 cial resources to manage them, and 

 even if the resources were available, 

 it is arguable whether these small- 

 scale fisheries would justify the ex- 

 penditure that such an exercise 

 would require. However, although 

 the overall yield of these fisheries 

 is modest, they may provide an im- 

 portant source of employment, pro- 

 tein, and foreign exchange earnings 

 for local economies. 



In a pioneering study based on 

 catch and effort data collected dur- 



ing a single survey of landing sites 

 that he grouped by coastal parishes, 

 Munro (1978) developed a prelimi- 

 nary surplus production model 

 (SPM) for Jamaican reef fisheries. 

 His approach was attractive because 

 data inputs and analytic require- 

 ments were modest, and the model 

 provided long-term, albeit simple, 

 guidance for optimal fishing levels. 



However, the area-based SPM 

 assumes that the fish assemblages, 

 their habitats and productivity, and 

 the fishery do not differ signifi- 

 cantly among fishing areas; that the 

 relationship between catch and ef- 

 fort is at equilibrium in each area; 

 and that the fish stocks and effort 

 are contained within the designated 

 fishing areas (Caddy and Garcia, 

 1982; Nicholson and Hartsuijker, 

 1982). Nicholson and Hartsuijker 

 ( 1982 ), in particular, pointed out the 

 perils of violating the model's as- 

 sumptions, but area-based SPM's 

 for reef fisheries are being used in- 

 creasingly to obtain first-order ap- 

 proximations of maximum sustain- 

 able yield based upon available catch 

 and effort data (Aiken and Haught- 

 on, 1987; Haughton, 1988; Appel- 



737 



