Fishery Harvest and Population Dynamics of Gray Snapper, Lutjanus Griseus, in Florida Bay and Adjacent Waters

Catches of gray snapper, an important recreational gamefish species in south Florida, have been monitored nearly continuously since 1958 in Everglades National Park; total harvest and effort data have been collected since 1973, and lengths have been measured since 1974. Catch rates of gray snapper have fluctuated greatly since 1958 with peaks in 1959, 1964–1966, and 1977–1979. Most of the total annual harvest from 1973 to 1985 was taken by sport fishermen (78%) and guided parties (21%) with the remaining 1% taken by commercial hook-and-line fishermen and net fishermen. Total annual harvest of gray snapper in Florida Bay and adjacent waters dropped from 129,000 to 99,500 fish between 1973–1976, increased greatly to 156,000 fish in the mid-1970's, but declined again during the 1980's to 59,000 fish. Effort was linearly correlated with harvest (r ² = 0.973, N = 13). The great increase in harvest in the mid-1970's was due to a great increase in guide harvest. The decline in effort, harvest, and harvest rates for gray snapper since 1979 is believed due to increased effort for other species such as spotted seatrout, as well as reduced stock abundance and recruitment. Gray snapper recruit to the park fishery at age 1 and are found in the catch to at least 7 years. Three and 4-year-old fish make up 87% of the catch. Gray snapper are believed to migrate offshore out of the park to spawn since very few ripe adult fish have ever been found in the park. Gray snapper along the keys and Florida's east coast live to at least 21 years old. Although fishing mortality on gray snapper in the park is high, averaging F = 0.76, and the stock is growth-overfished, population size and recruitment are not controlled by fishing effort within the park. Environmental factors and possibly fishing effort on gray snapper in the adjacent Florida Keys may control stock size.