Florida pompano, continued 



Avault 1 970, Perret et al. 1 971 , Christmas and Waller 

 1 973), and adults from a temperature range of 17.0° to 

 31 .7°C (Finucane 1 969a, Johnson 1 978). The majority 

 of fish collected are from a temperature range of 28.0 

 to 31 .7°C (Finucane 1 969a). Temperature appears to 

 strongly affect the presence and behavior of this spe- 

 cies. Experimental work has shown the need for stable 

 temperatures for maximum growth, with the ideal tem- 

 perature being 25.0°C or above (Finucane 1969b). 

 Feeding is reduced below 18.0°C, and ceases at 

 1 3.0°C. Activity is also greatly reduced at this tempera- 

 ture (Finucane 1968). Physiological shock becomes 

 evident at about 12.0°C with partial to complete kills 

 occurring from 10.0° to 15.5°C (Berry and Iversen 

 1967, Moe et al. 1968). All fish have an upper lethal 

 limit of about 38.0°C, although small juveniles have 

 been observed in tide pools at temperatures above 

 46.0°C (Moe et al. 1968). 



Gulf of Mexico, larvae are present May through August 

 (Ditty et al. 1988) as they move with currents. Young 

 pompano arrive in the surf zone as juveniles, at a size 

 of approximately 1 to 1 5 mm TL (Bellinger and Avault 

 1 970, Bellinger and Avault 1 971 , Christmas and Waller 

 1973, Finucane 1969a, Gunter 1945, Hoese 1965, 

 Moe et al. 1968, Perret et al. 1971, Modde 1980, 

 Modde and Ross 1 981 ). Juveniles leave the surf zone 

 when 75 to 150 mm TL for deeper water and move 

 south along the coast, probably in response to colder 

 winter temperatures (Bellinger and Avault 1 970, Berry 

 and Iversen 1967, Fields 1962, Gunter 1945, Iversen 

 and Berry 1969, Swingle 1971). 



Reproduction 



Mode : This species has separate male and female 

 sexes (gonochoristic). Fertilization is external, by 

 broadcast of milt and roe. 



Salinity - Eggs and Larvae: Under laboratory condi- 

 tions, eggs developed up to middle and late gastrula- 

 tion at salinities of 31 .2 to 37.71%o (Finucane 1969b). 



Salinity - Juveniles: Juveniles have been reported from 

 salinities ranging from 9.3 to 36.7% , with a preference 

 shown for 20%o and higher (Gunter 1 945, Springer and 

 Woodburn 1960, Gunter and Hall 1963, Gunter and 

 Hall 1965, Finucane 1968, Finucane 1969a, Bellinger 

 and Avault 1970, Perret et al. 1971, Swingle 1971, 

 Christmas and Waller 1973). One collection from 

 Laguna Madre, Texas reported large schools at 45 to 

 50%o (Simmons 1967). Fish in laboratory conditions 

 were able to tolerate salinities down to 1 .27%o (Moe et 

 al. 1968). 



Salinity - Adults: Adults occur in salinities from 32.1 to 

 35.6%o. They do not normally enter water less than 

 32%o, although fish in captivity were acclimated to 

 1 .27%o (Moe et al. 1 968, Johnson 1 978). 



Dissolved Oxygen: This species has been collected 

 from a dissolved oxygen (DO) range of 3.43 to 5.64 

 parts per million (ppm), but is adversely affected below 

 4 ppm with death occurring at about 2.5 ppm (Finucane 

 1969a, Moeetal. 1968). 



pH: Experiments with pH showed physiological shock 

 at 1 1 .9 and 3.9 on either end of the scale, and death 

 occurring at 12.4 and 3.7 (Moe et al. 1968) 



Movements and Migrations 



The Florida pompano apparently undergoes extensive 

 migrations, but patterns of movement are not clearly 

 known. Spawning apparently takes place in offshore 

 waters in early spring to late summer in the Gulf Stream 

 or in locations where transport of eggs and larvae are 

 influenced by current (Fields 1 962, Moe 1 972). In the 



Spawning : Spawning has not been directly observed. 

 Specific spawning areas are unknown, but they are 

 probably offshore (Fields 1962, Berry and Iversen 



1967, Finucane 1969a, Sabins and Truesdale 1974, 

 Fahay 1975, Gilbert 1986), and spawning may occur 

 over an extended period of time. It may begin as early 

 as February and peak from April to June followed by 

 lesser spawnings in summer and early fall (July-Octo- 

 ber). Spawning throughout the year is possible in the 

 tropical Gulf of Mexico and the Caribbean Sea (Gunter 

 1 945, Gunter 1 958, Berry and Iversen 1 967, Finucane 

 1 969a, Iversen and Berry 1 969, Christmas and Waller 

 1973, Sabins and Truesdale 1974). 



Fecundity : Maturity probably occurs after one year with 

 spawning unlikely until the second year (Finucane 



1968, Moe et al. 1968). At least four different egg 

 development stages are present in adult females indi- 

 cating multiple spawning (Finucane 1968) with an 

 average size female containing 4 to 8 hundred thou- 

 sand eggs (Finucane 1968, Moe et al. 1968, Finucane 

 1969a). 



Growth and Development 



Egg Size and Embryonic Development : Mature unfer- 

 tilized eggs are round, symmetrical, and average 0.7 

 mm in diameter. They possess a large yolk with a 

 narrow perivitelline space occupying 10 to 15% of the 

 egg volume. One oil globule is evident, and the surface 

 of the egg is smooth (Finucane 1968,1969a). Fertil- 

 ized eggs are spherical with a single, large oil globule, 

 partially segmented yolk mass, narrow perivitelline 

 space, and a sculptured membrane. Average diam- 

 eter of the oil globule and egg is 0.29 mm, and 0.92 mm 

 respectively. Eggs are almost colorless and have an 

 irregularly segmented light yellow yolk. The oil globule 

 is nearly spherical and is dark yellow in a position at the 

 top of the egg. No chromatophores are present 



224 



