Abstract. — A study was made 

 of age, growth, and reproduction of 

 the king mackerel Scomberomoru^ 

 cavalla in Trinidad waters captured 

 by hook-and-line and drift gillnets. 

 Ages, estimated from otolith rings, 

 ranged from to VII in males and 

 from to X in females. Mean back- 

 calculated lengths in 99 males ranged 

 from 43.7 cm FL at the end of year 

 I to 85.9 cm FL at the end of year 

 VI, and in 233 females from 41.8 cm 

 FL at the end of year I to 105.6 cm 

 FL at the end of year VIII. The von 

 Bertalanffy growth equations were 

 for males, L„ = 112.3 [1 - exp(-0.18 

 (t + 1.80))] and for females L„ = 140.1 

 [1 - exp(-0.15(( + 1.52))]. Based on 

 gonad examination of 97 males and 

 224 females, spawning takes place 

 throughout the year around the island, 

 with peak spawning from October 

 through March, a period associated 

 with low salinity. First spawning takes 

 place at ages I-II for both sexes. 

 Females predominated in all size 

 groups, with the proportion of males 

 increasing during the peak spawning 



Age, Growth, and 

 Reproduction of the King 

 Maclcerel Scomberomorus cavalla 

 (Cuvier) in Trinidad waters 



Maxwell G. de L. Sturm 

 Premila Salter 



Institute of Marine Affairs, P O Box 3160 

 Carenage Post Office, Trinidad. West Indies 



Manuscript accepted 1 1 December 1989. 

 Fishery Bulletin, U.S. 88:361-370. 



The king mackerel Scomberomorus 

 cavalla (Cuvier) (Scombridae) occurs 

 in coastal waters of the western At- 

 lantic ranging from the Gulf of Maine 

 to Rio de Janiero (Briggs 1958). It 

 has also been reported throughout 

 most of the West Indies (Erdman 

 1949), and its distribution is said to 

 extend eastwards to Africa (Jordan 

 et al. 1930). However, more recent 

 reviews (Collette and Russo 1979) 

 make no mention of S. cavalla in the 

 Eastern Atlantic, although it has 

 been reported from St. Paul's Rocks, 

 a group of small islands in the mid- 

 Atlantic (Lubbock and Edwards 1981). 

 Scombermyvonis cavalla has commer- 

 cial and recreational value through- 

 out its range. Griffiths (1971) consid- 

 ered Scomberomorus spp., especially 

 S. cavalla and S. maculatus ( = S. 

 brasiliensis Collette et al. 1978) to 

 have greater commercial potential 

 than the timas in Venezuela. The gen- 

 eral biology of S. cavalla has been in- 

 vestigated in North American waters 

 (Beaumariage 1973) and off the state 

 of Ceara, northeastern Brazil, includ- 

 ing age and growth studies (Nomura 

 and Rodrigues 1967, Ximenes et al. 

 1978). Manooch et al. (1978) provided 

 a useful annotated bibliography on 

 this species, and many aspects of its 

 biology and fishery have been sum- 

 marized by Collette and Russo (1984). 

 More recent work includes studies on 

 reproduction (Finucane et al. 1986) 

 and growth (Manooch et al. 1987) in 

 North American waters. 



In Trinidad, Whiteleather and Brown 

 (1945) and more recently Sturm et al. 

 (1984) reported that S. cavalla. ap- 

 proached S. maculatus ( = S. brasili- 

 ensis) as the most abundant continen- 

 tal pelagic species in commercial land- 

 ings. The Scomberomorus fishery in 

 Trinidad is artisanal and seasonal 

 from March through October, and S. 

 cavalla is caught mainly by hook-and- 

 line (trolling and live-bait fishing) and 

 drift gillnets (Sturm et al. 1984). This 

 paper provides information on age, 

 growth, and reproduction of S. caval- 

 la (the kingfish or thazard) in Trini- 

 dad waters. 



Materials and methods 



The climate of Trinidad is tropical, 

 with a wet season from June to De- 

 cember. The surrounding waters are 

 mainly estuarine. Surface tempera- 

 tures vary little, ranging from 27 to 

 29°C (van Andel and Postma 1954, 

 Edwards 1983). Further details of the 

 study area may be found in Sturm 

 (1978). 



Fish were bought from artisanal 

 fishermen in 1981-82 at six beaches: 

 Maracas and Las Cuevas in the north, 

 Mayaro and Guayaguayare in the 

 southeast, and Cedros and Icacos in 

 the southwest of the island. Artisan- 

 al catches consisted mainly of both 

 Scomberomorus species, which on be- 

 ing landed were separated into bask- 

 ets. There were usually not more than 

 about a dozen boats fishing on any 



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