specimens were an extreme rarity, other examples not 

 having been found in the past 50 yr in spite of diligent 

 research (Sparta, 1961). 



3.23 Adolescent phase 



A juvenile specimen of T. belone (356 mm) was 

 reported (as Istiophorus gladius (Broussonet) by Ben- 

 Tuvia (1953:18), which was subsequently reidentified 

 (Ben-Tuvia, 1966) as T. belone. A second specimen 

 (597 mm) was collected by the Woods Hole 

 Oceanographic Institution's RV Chain off Lebanon. 

 The striking characteristic of these specimens is that 

 they generally resemble the adult except that the first 

 dorsal fin is high and saillike, almost as in the genus 

 Istiophorus (see de Sylva, 1963b:Fig. 2). A high dorsal 

 fin in the adolescent phase is common to all 

 istiophorids, and accounts for much misidentification 

 of young stages in the literature. 



The dorsal fin is unlike that of the young of 

 Istiophorus in that it lacks diffuse blotches (see 

 Gehringer, 1956, 1971; de Sylva, 1963b:Fig. 3). Is- 

 tiophorus has not been reported from the Mediterra- 

 nean, nor has the blue marlin, Makaira nigricans 

 Lacepede, but both could occur there and should be 

 looked for (de Sylva, 1973). The dorsal fin of the 

 young of Makaira is distinctively convex, reaching its 

 highest point anteriorly. It has a distinct wavy pattern 

 not seen in other istiophorids. Young of Tetrapturus 

 albidus are known from North Carolina (de Sylva, 

 1963b: Fig. 1) and off Havana (Anonymous, 1968). 

 They have five or six distinctive dark ocelli rimmed 

 with pale areas, near the base of the first dorsal fin. 

 The young of T. belone is unique in that the dorsal fin 

 bears several small, dark blotches at the bases of the 

 anterior rays, and at the tips of the first few rays, 

 the rest of the fin being dusky and otherwise un- 

 marked. 



Other features of development between the adoles- 

 cent and adult stages are less distinctive. The body of 

 the adolescent is typically thin and slab-sided, which 

 increases in robustness in the adult. The bill, long and 

 slender in the adolescent, is negatively allometric, be- 

 ing relatively short in the adult. Characteristic of all 

 the spearfishes is the shape of the first dorsal fin in the 

 adult, which has a slight lobe anteriorly, sloping 

 abruptly behind the first several rays, then running 

 long and high, paralleling the dorsal profile (see 

 Robins and de Sylva, 1960:406; 1963:93, Fig. 4). 



3.3 Adult Phase 



3.31 Longevity 



Nothing is known of the rate of growth or maximum 

 age of T. belone. Size-frequency analysis of adults, 

 used by de Sylva (1957) to estimate age and growth of 

 Istiophorus americanus, requires a great deal of size 

 data from individual specimens, which are presently 

 unavailable. 



3.32 Competitors 



Tetrapturus belone is ecologically quite similar to 

 the broadbill swordfish and T. albidus, with which it 

 undoubtedly competes for food. The blue shark, 

 Prionace glauca, and the bluefin tuna, Thunnus thyn- 

 nus, are other large predators which occur in the same 

 ecological niche and which probably feed upon the 

 same organisms. The broadbill swordfish and the 

 bluefin tuna are routinely caught by commercial 

 fishermen about Sicily using the same harpoon and 

 trap-net techniques by which T. belone is taken. 



3.33 Predators 



Because of the relatively large size attained by T. 

 belone, it is probably not preyed upon extensively in 

 the adult phase except by sharks. The blue shark is 

 occasionally common off Sicily and probably could be 

 considered as an important predator, though the blue 

 shark, being somewhat sluggish, would probably be 

 more successful in capturing species not as swift as T. 

 belone. 



3.34 Parasites, diseases, injuries, and ab- 

 normalities 



Nothing has been published on parasites and dis- 

 eases of T. belone. A parasitic copepod (Penella), 

 common on all istiophorids, has not been reported for 

 T. belone. Abnormalities, such as deformed dorsal 

 fins, broken or bent bills, and broken pectoral or 

 caudal rays, are common among other istiophorids, 

 but no such deformities are reported for T. belone. 



3.4 Nutrition and Growth 

 3.41 Feeding 



Feeding habits of T. belone have not been reported 

 in the literature. Based on their food habits, however, 

 they probably are visual feeders of the upper, well-lit 

 layers. It is not known if they feed at night. Antonio 

 Sparta reports (in Robins and de Sylva, 1963) that T. 

 belone follows schools of Atlantic sauries, 

 Scomberesox saurus, into the Strait of Messina and, 

 hence, in this region they are feeders in the shallower 

 strata of the epipelagic zone. Sparta (1961:20) wrote 

 that T. belone preferred the upper waters of the Strait 

 of Messina. 



Probably because there is considerable upwelling of 

 food and nutrients into the upper layers of the Strait 

 of Messina, T. belone finds an ample food supply in 

 the upper waters so that it does not have to search the 

 deeper strata for food, such as occurs with many other 

 istiophorids. About Messina, fishermen harpoon them 

 during their fishing period from early in the morning 

 (0530-0600) until about 1600. Since night fishing is 

 not carried out here, therefore, specimens have not 

 been studied to disclose if they feed at night. 

 Cavaliere (1962:172) reported that, to the south of the 



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