Koslow et al.: Catch and effort analysis of reef fisheries 



745 



sumption of equilibrium. In Jamaica, one index of 

 fishing effort, the number of fishing canoes, ap- 

 pears to have declined by 55% over the past de- 

 cade. In a 1981 survey, 2,137 fishing canoes were 

 recorded along the south coast (Haughton, 1988) 

 but only 963 in the present study. (Because the 

 fishery could be easily censused, the number of 

 canoes on fishing beaches was the primary mea- 

 sure of fishing effort in most previous studies of 

 Jamaican reef fisheries [Munro, 1978, 1983; 

 Haughton, 1988]). Landings offish from the south 

 Jamaican shelf declined 82% during this decade 

 from 5,475 metric tons (t) in 1981 (Haughton, 

 1988) to 998 t in 1991. The decline in landings 

 and effort resulted in a 60% decline in CPUE from 

 2.56 to 1.04 t/canoeyr. The decline in fishing ef- 

 fort may be a consequence of falling catch rates. 

 The datum for CPUE in relation to /"for 1991 does 

 not fall along the line defined by the 1968-1981 

 data for the Jamaican fishery (Fig. 5), possibly be- 

 cause the fishery is not at equilibrium, that is, it has 

 not recovered in response to recently reduced effort. 



It may be expected that estimates of sustainable 

 yield and effort obtained from the present survey 

 would be significantly lower than previous estimates 

 owing to reduced levels of CPUE, catch, and effort. 

 Munro ( 1978) estimated that MSY for the Jamaican 

 reef fisheries was 4.1 t/km 2 and that f was 3.2 

 canoes/km 2 shelf area. These estimates were based 

 primarily on data from the north coast, where the 

 shelf is narrow and much of the substrate is coral, 

 therefore they are probably comparable to our esti- 

 mates based upon the coral and sea-grass fraction of 

 the south Jamaican shelf. Munro's spatially based 

 SPM used data from a 1968 fishery survey. Haughton 

 (1988) developed an SPM for the Jamaica reef fish- 

 ery based upon three fishery surveys of the north 

 and south Jamaican shelves conducted between 1968 

 and 1981. Differences in the productivity per unit 

 area of the north and south Jamaican shelf were not 

 considered. Haughton estimated MSY for the south 



Fishing intensity (canoes/km^) 



Figure 5 



The relationship of catch per unit of effort for the Jamai- 

 can reef fisheries based upon data from 1968 to 1981 (from 

 Haughton, 1988) and from the present study. Data are 

 shown for reef fisheries off the north (N) and south (S) 

 coasts of Jamaica. ( ' ) indicates data from the southern shelf 

 that have been corrected for the proportion of reef and 

 sea grass habitat. The regression line is based upon the 

 original, uncorrected data from 1968 to 1981. 



Jamaican fishery to be 2.2 t/km 2 of shelf with an/ 1 

 of ~1 mechanized canoe/km 2 . (The units of effort of 

 the Munro and Haughton models are not entirely 

 comparable because most canoes became mechanized 

 after Munro's survey; Haughton standardized his 

 effort data to the mechanized canoe.) If the data for 

 the southern shelf in Haugh ton's model are normal- 

 ized per unit of area of productive habitat (~50% of 

 the total shelf area), so that data from the north and 

 south coast are comparable, the revised estimates of 

 MSY and f ' are 3.1 m/km 2 and 1.5 canoes/km 2 of 

 productive habitat. However, there is no longer a sig- 

 nificant relationship between CPUE and /"(Fig. 5). 

 Our estimate of MSY for the combined Jamaican and 

 Belizean reef fisheries is 1.0 t/km 2 (Table 4). Based 

 upon present effort in Jamaica being 89% of f . 

 (/=3,099 hook h/km 2 [Table 2];/ =3,497 hook h/km 2 



ii l J " msy ' 



[Table 4]),/" may be estimated to be approximately 

 0.6 canoes/km 2 of productive habitat; the present 

 density of canoes is 963 canoes over a productive shelf 



