Abstract. The tripletail, 



Lobotes surinamensis, is the only 

 member of the family Lobotidae in 

 the western Atlantic Ocean, and 

 its life history is poorly under- 

 stood. We describe development of 

 tripletail larvae, clarify the litera- 

 ture on their identification, and 

 discuss their temporal and spatial 

 distribution in the northern Gulf 

 of Mexico. Larval tripletail are 

 characterized by 1) a vaulted, me- 

 dian supraoccipital crest with 

 spines along the leading edge; 2) 

 precocious, heavily pigmented pel- 

 vic fins; and 3) large preopercular 

 spines. In addition, the surface of 

 the frontal and supraoccipital 

 bones have a reticulated pattern of 

 depressions or "waffled" appear- 

 ance. Transition to juvenile stage 

 begins at about 9.0-9.5 mm stan- 

 dard length. Tripletail have three 

 supraneurals, six branchiostegal 

 rays, 11 + 13 vertebrae, 27 dorsal 

 rays (XII, 15), and 14-15 anal rays 

 (III, 11-12). Overall, 75% of trip- 

 letail larvae were found in waters 

 >28.8°C, >30.3 ppt, and at stations 

 >70 m deep. Larval tripletail were 

 collected primarily from July 

 through September and almost 

 exclusively in surface tows. Triple- 

 tail spawn offshore. Juveniles, al- 

 though sporadic, are apparently 

 not uncommon in Gulf of Mexico 

 estuaries during summer. 



Larval development of tripletail, 

 Lobotes surinamensis (Pisces: 

 Lobotidae), and their spatial and 

 temporal distribution in the 

 northern Gulf of Mexico* 



James G. Ditty 



Center for Coastal, Energy, and Environmental Resources 

 Coastal Fisheries Institute, Louisiana State University 

 Baton Rouge, LA 70803 



Richard F. Shaw 



Center for Coastal, Energy, and Environmental Resources 

 Coastal Fisheries Institute, Louisiana State University 

 Baton Rouge, LA 70803 



Manuscript accepted 4 October 1993 

 Fishery Bulletin 92:33-45 (1994) 



The percoid family Lobotidae is 

 usually considered to comprise two 

 genera with about four species 

 (Nelson, 1984), although Johnson 

 ( 1984) only included Lobotes, ques- 

 tioning the affinity of Datnioides. 

 The tripletail, Lobotes surinamen- 

 sis, is cosmopolitan and found in all 

 warm seas (Fischer, 1978); one 

 adult was recorded as far north as 

 St. Margarets Bay, Nova Scotia 

 (44°37'N, 64°03'W (Gilhen and 

 McAllister, 1985). Lobotes surina- 

 mensis is the only member of the 

 family in the Gulf of Mexico (Gulf) 

 (Hoese and Moore, 1977). Tripletail 

 generally occur along the Gulf 

 coast from April through early Oc- 

 tober (Baughman, 1941) and mi- 

 grate south during fall and winter 

 (Merriner and Foster, 1974). Al- 

 though apparently abundant no- 

 where, adult and juvenile tripletail 

 are not uncommon in bays, sounds, 

 and estuaries along the north-cen- 

 tral Gulf coast during summer 

 (Baughman, 1941; Benson, 1982). 

 Tripletail up to 18.6 kg and 89 cm 

 standard length (SL) have been 

 caught, but most average between 

 1 and 7 kg (Gudger, 1931; Baugh- 

 man, 1941). Tripletail often are in- 



cluded as a category in Gulf fishing 

 rodeos (Benson, 1982) because of 

 their reputation as "a bold biter" 

 and strong fighter (Gudger, 1931; 

 Baughman, 1941). Tripletail enter 

 the commercial catch on the east 

 and west coasts of Florida and a 

 few tons are taken annually 

 (Fischer, 1978). 



The development of tripletail lar- 

 vae and their spatial and temporal 

 distribution is poorly understood. 

 Hardy ( 1978) compiled information 

 on tripletail life history. Uchida et 

 al. (1958) and Konishi (1988) pro- 

 vide limited information and illus- 

 trations of tripletail larvae off Ja- 

 pan; however, Konishi's 5.1-mm 

 larva is misidentified. Johnson 

 (1984) commented on cranial mor- 

 phology. Our objectives were to de- 

 scribe the development of tripletail 

 larvae, to clarify the literature on 

 their identification, and to discuss 

 the spatial and temporal distribu- 

 tion of larval tripletail in the north- 

 ern Gulf of Mexico. 



* Louisiana State University Coastal Fish- 

 eries Institute Contribution No. LSU- 

 CFI-92-8. 



33 



