Population structure, food habits, and spawning activity of 1026 gray snapper Lutjanus 
griseus were studied in Everglades National Park from November 1978 through 
January 1980. Fish were sampled from sportfishermen catches and ranged in length 
from 111 - 451 mm FL (x = 257 ± 3.2 mm) and in weight from 0.05 - 1.6 kg (x = 0.33 
± .02 kg). There was no difference in mean length between sexes. Fish aged from scale 
annuli ranged from one to seven years. Two- and three-yr old fish dominated the catch. 
Recruitment was complete by age three. The mean age of all fish was 3.0 ± 0.1 yrs. 
There was no difference in mean age between the sexes. Fish taken from the Cape Sable 
area were significantly older than fish taken from other areas. Calculated growth of 
gray snapper was greatest in the first year and relatively linear before increasing in 
the fifth year. Calculated growth varied between sexes and among areas of capture. 
Females were significantly larger than males at one and two. Fish taken from 
hypersaline areas near the Gulf of Mexico were larger at ages one through four than 
fish taken from seasonally brackish waters. Males in the Shark River area did not show 
as great an increase in weight length as did all fish in other areas. Females in the Coot 
Bay and Whitewater area were heavier at a given length than all fish in other areas. 
Annual survival rate of all fully recruited fish was s = 0.28 ± .03. Survival of males 
was higher than females. Gray snapper survival was higher in hypersaline waters near 
the Gulf than in other areas. Spawning activity probably occurs outside of park waters. 
Only four of 668 examined inside park waters were ripe. Park gray snapper diet 
consisted mainly of fish, shrimp, and crabs. Species composition of the diet varied with 
age and among seasons and areas of capture. Comparison of this study with an earlier 
study of Park gray snapper showed increases in survival and longevity since 1960. No 
changes in diet, spawning activity, or growth rate were noted. 
1979 
Anonymous (1980) Pesticide use observations, Monroe County, Florida, March - June 
1979. USEPA, National Enforcement Investigations Center (NEIC), Denver, CO. 36 pp. 
From June 3 to 14, 1979, a pesticide use observation study was conducted by the 
National Enforcement Investigations Center (NEIC) in Monroe County. During the study, 
an EPA team evaluated the environmental effects resulting from the aerial application 
of Naled (Dibrom-14) and ground application of Baytex for the control of mosquitoes. A 
reconnaissance survey in March of the marine environment in the Everglades National 
Park revealed no pesticide residues were detected prior to the initiation of the 
mosquito control program by Monroe County. Lack of precipitation in the spring reduced 
mosquito breeding activities and consequently the necessity for intensified pesticide 
applications. Records indicate only three aerial and two ground application occurred 
from June 3 to 14, 1979. Of the 37 surface water samples collected from the 
Everglades National Park marine environment, two contained detectable amounts of 
pesticide. At Station 10 on June 5, Naled was found at a concentration of 0.02 mg/L. On 
June 14 at Station 04, Naled appeared at a concentration of 0.06 pig/L. No Baytex was 
found in the water samples. Pesticide drift into the area adjacent to the Park was 
confirmed by the use of Hi-Vol air samplers at Station 12 (Ranger Station) on three 
occasions. On June 4, filter paper in the Hi-Vol samplers captured 0.18 pig of Baytex 
sprayed via ground applications. June 5 and 12 the air monitoring filters revealed a 
capture of 0.06 pig and 0.02 pig respectively. Uptake by exposed marine organisms of 
the applied pesticide was negligible. The only observed instance of uptake occurred at 
Station 05 (Manatee Creek) where the oysters accumulated an average of 0.007 pig/g 
of Naled. Baytex was not found in detectable amounts. Field analyses of hydrographic 
conditions were made daily throughout the 11-day study to determine if the aquatic 
environment affected the survival rate of the test animals. From June 3 to 14, records 
revealed that conditions were at a seasonal norm and as such appeared to have had no 
direct influence on test organism survival during the exposure studies. The test to 
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