in December- February; most of those which mi- 

 grated southward were released in November- 

 February and recaptured in November-March. 

 Most of those recaptured within 20 miles (32 km) of 

 the release point were released in November- 

 January and June, and recaptured in November- 

 December and February- April. The longer north- 

 ward migrations (Key West-Marathon to Palm 

 Beach-Stuart) were by four fish, released in March, 

 April. October, and November and recaptured in 

 December, January, May, and July. The longest 

 southward migrations (Palm Beach-Stuart to Key 

 West-Islamorada) were by four fish, released in 

 January, March, and April, and recaptured in 

 January. February. March, and July. There seems 

 to be little consistency in these data. 



Two rather rapid southward migrations along the 

 Florida coast have been recorded; from off Jupiter 

 to off Fort Lauderdale in 2 days, and from off Hills- 

 boro Inlet to off Miami in the same period. It 

 might be of interest to check such migrations 

 against historical weather data. Fishermen in the 

 area often observe sailfish riding the downwind face 

 of waves with the upper lobe of their caudal fin 

 showing ("tailing"), particularly during the brisk 

 northerly winds which herald cold weather. 



Growth and Survival 



Since sizes at release are estimated, and the qual- 

 ity of recapture data is difficult to evaluate, espe- 

 cially in regard to length measurements, no valid 

 growth data are available. In the WHOI program in- 

 structions, the cooperating taggers are asked to mea- 

 sure the length of the head of each billFish tagged, 

 which would permit a close estimate of the 

 body length of the fish. No taggers have done this. 

 Besides the extra time and trouble involved, this 

 procedure might well increase the risk of injury to 

 both fish and tagger. Several sailfish were recap- 

 tured after from 1 to 4 yr at liberty. These do not 

 appear to have been especially small when tagged, 

 or especially large when recaptured. This may be an 

 indication that the species does not grow very fast 

 after reaching the age of recruitment to the fishery. 



Eighty-eight of the 108 recaptured sailfish for 

 which time at liberty was known, at least approxi- 

 mately, were recaptured less than a year after being 

 tagged. Only 11 more had been at liberty for 12-18 

 mo, and an additional five for 18-24 mo. Thus only 

 four were recaptured after from 2 to 5 yr at liberty. 

 These results are in good agreement with de Sylva's 



(1957) work, which indicated that the life span of 

 the species was short. 



The question of the survival of released fish re- 

 mains unanswered. The low return rate for tagged 

 sailfish could be an indication of high tagging mor- 

 tality. Return rates also depend on the percent of 

 the stock which is caught, as well as on natural 

 mortality, tag shedding, and other factors. Return 

 rates for white marlin and small bluefin tuna were 

 even lower than those for sailfish in the years 

 1954-1961, but, with the increased fishing effort for 

 these species, the rates for white marlin have risen 

 appreciably, and those for small bluefin have be- 

 come alarming (FAO, 1968; Mather, Jones, and 

 Beardsley, 1972; Mather et al., 1974). Only two 

 rather small and localized commercial fisheries 

 have returned significant numbers of sailfish tags; 

 over 80% of the tags have been returned by sport 

 fishermen. In the absence of an effective commer- 

 cial fishery, a high return rate from such a short- 

 lived and widely ranging species can hardly be ex- 

 pected. Experiments to study the survival of tagged 

 fish, possibly through the use of acoustic tags, are 

 needed to settle this important question. 



Comparison of Tag Types 



Data from the early years provide indications of 

 the practicality and effectiveness of the various 

 types of tags. In the RSMAS program, the disc tag 

 was soon discarded because of the difficulty en- 

 countered by the fishermen in twisting the wires to 

 assure a snug fit on the bill without keeping the fish 

 out of water too long. The neoprene rubber ring was 

 discarded after a single recapture showed that the 

 pressure of the rubber on the bill was actually sever- 

 ing the bill. The cattle tags were popular with the 

 anglers; they could be applied quickly. However, 

 they were often knocked from the special pliers by 

 the struggling fish and the pliers used to apply them 

 were expensive. The "Type B" Woods Hole dart 

 tag was the most popular with anglers since the fish 

 could be tagged without handling them (Mather, 

 1963). 



On the basis of recoveries, the cattle tag and the 

 Woods Hole Type B dart tag were about equally 

 effective. There is reason to believe that some tags 

 may have been overlooked by anglers since some of 

 those that were recovered had goose barnacles and 

 algae attached to them and could not be recognized 

 easily. 



In the tagging off Port Aransas, however, the cat- 



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