Table 1.— Countries from which catch data on the dolphin, Coryphaena hippurus, were obtained, with the data source for each country. 



RESULTS AND DISCUSSION 



Seasonality and Size Structure 

 of Catch 



The seasonality of dolphin catch in 14 territories 

 is shown in Figure 1. Martinique and Guadaloupe 

 supplied no data, but information was given on the 

 duration and peak of the dolphin season. It should 

 be noted that the U.S. Virgin Islands is the only ter- 

 ritory with a distinctly bimodal catch pattern. 



The peak months of catch in each territory are 

 superimposed on a map of the western central Atlan- 

 tic in Figure 2. Grenada peak catch is in February/ 

 March; Barbados, St. Vincent, and St. Lucia in 

 March/April; Martinique and Guadeloupe in April; 

 and the Virgin Islands in April/May, giving the 

 Virgin Islands their first and largest annual peak. 

 This pattern of catch seasonality is suggestive of a 

 stock (subsequently called the southern stock) 

 moving northwest through the island arc. If the 

 stock then turned west and moved past Puerto Rico, 

 we would expect peak catch there to be between 

 June, July, and August; but this is when Puerto Rico 

 catches the least dolphin (see Figure 1). We therefore 

 suggest that, on leaving the Virgin Islands, the stock 

 moves northeasterly into the Atlantic, completing a 

 circuit and returning to Grenada by February/March 

 of the following year. This implies that there is a sec- 



ond stock (subsequently called the northern stock) 

 located in the northwest region of the western cen- 

 tral Atlantic. It occurs near Puerto Rico between 

 December and February. It next moves northwest- 

 erly past the Bahamas in April/May Florida and 

 Georgia in May/June, South and North Carolina in 

 June/July and Bermuda in July/August. It then com- 

 pletes its circuit by passing through the Virgin 

 Islands, giving that territory its second and smaller 

 peak in November and returning to Puerto Rico by 

 December/February. 



The mean size of fish caught in five territories dur- 

 ing peak fishing season is shown in Figure 3, and 

 the size structure of the catch throughout the fishing 

 season in Barbados is shown in Figure 4. The data 

 are consistent with the migration circuits proposed. 

 In the northern stock, small presumably young-of- 

 the-year fish are predominant during the summer 

 when the stock is near Florida, North Carolina, and 

 Bermuda. The mean size taken by the sport fishery 

 in Florida is 1.69 kg; in North Carolina, where they 

 occur 1 mo later, it is 2.92 kg and in Bermuda, where 

 they occur 2 mo later, it is 3.85 kg. These differences 

 presumably reflect growth within the cohort. The 

 largest fish are taken by Puerto Rico, where Erd- 

 man (1956) reported that dolphin up to 23 kg in 

 weight occur during the peak winter fishing season, 

 and by the Bahamas where the mean weight during 

 the peak fishing months is 6.45 kg. This suggests 



452 



