all become males. Factors influencing sexual change are not well understood. 

 The transformation possibly prevents the loss of males from the highly terri- 

 torial populations found in the relatively isolated reef areas. 



The increasing catch of snappers and groupers by commercial and sport 

 fishermen may be reducing their abundance. For example, in recent years over- 

 fishing in some areas is indicated by the declining average size of fish 

 caught. 



The relatively great distance of fish populations offshore and rising 

 fuel prices may depress the sport fishery, yet commercial fishing for these 

 species in coastal waters may increase even further because Mexican fishing 

 grounds now prohibit U.S. fishermen. 



The Mackerel s 



The m&ckerel ( Scomberomorus spp .) are a valuable sport and commercial 

 fish in the coastal waters of Northwest Florida. They are two of the most 

 popular sport species; estimates indicate that the sport catch is about three 

 times greater than the commercial catch. The fishery management plan for pe- 

 lagic coastal fishes in Florida currently under preparation by the Gulf of 

 Mexico and South Atlantic Regional Fishery Management Councils (Public Law 

 94-265) seeks to allocate 9 million lb annually to commercial fishemen 

 (approximately 5 million to nets and 4 million to hook and line) and 29 mil- 

 lion lb to sport fishennen. Competition between sport and commercial fisher- 

 men and between various groups of commercial fishermen is a serious problem. 

 Several legislative attempts to restrict specific types of fishing have been 

 made (e.g., making net fishing for mackerel illegal or banning commercial 

 fishing for the species altogether). 



King mackerel . Although a valuable sport fish in Northwest Florida, com- 

 mercial production of this species ( Scomberomorus cavalla ) is only a small 

 part of the State total. Florida landings averaged about 5.5 million lb an- 

 nually in 1970-80 and Northwest Florida's commercial landings fluctuated from 

 34,000 lb to 241,173 lb. The value of the catch from Northwest Florida in 

 1980 was $97,533 for the 182,970 lb landed. Monthly landings in 1965, 1970, 

 and 1975 for the Florida west coast are given in Table FSH-24 in the Data 

 Appendix. 



King mackerel begin spawning when three years old (males) and four years 

 old (females). Spawning from May to September has been well documented in 

 offshore waters of Texas and Northwest Florida and from Florida to North Caro- 

 lina along the Atlantic coast. Relatively little is known about the juveniles 

 although some are occasionally taken nearshore in shrimp trawls. King mack- 

 erel may live 13 to 14 years, but most are less than seven years. Adult mor- 

 tality is estimated at about 50% per year. 



Tagging studies have shown extensive migrations. Some of the king mack- 

 erel tagged in the winter along the southeast Florida coast migrated into the 

 Gulf of Mexico in the spring and migrated as far as eastern Texas and Mexico 

 in the summer. Most return to Florida waters in fall and winter. King mack- 

 erel also migrate along the Atlantic coast; fish tagged in southeast Florida 

 were caught from as far north as Virginia. Data so far indicate that there 



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