may congregate in response to abundance or 

 scarcity of food during this time but schools are 

 not formed. 



At the start of the spawning migration into the 

 Gulf of Mexico, however, the pinfish school in 

 large numbers. These schools seem to consist of 

 fish of the same age. Large numbei"s of pinfish cap- 

 tured in Chesaioeake Bay in October, as noted by 

 Hildebrand and Schroeder (1927), probably were 

 schools of seaward migrants. Aggregations of pin- 

 fish have also been seen in the Gulf of Mexico 

 (Springer, 1957). In the late winter and spring, 

 I have observed schools of pinfish in Santa Rosa 

 Sound, Fla., that were probably returning from 

 the Gulf of Mexico. Most of these fish were in their 

 second year of life. Few fish live to reenter the 

 estuary in their third year. 



The stage of gonad development before migra- 

 tion varied. In most years, maturation of gonads 

 l)robably takes place during the migration or 

 while the fish are at or near the offshore spawning 

 site. In October 19ti5, when most fish over 80 mm. 

 were mature enough to permit determination of 

 sex, the gonads ranged from the late stage 1 to the 

 late .stage 3 of Homans and Vl-adykov (1954) — 

 gonads growing in size; yellow, opaque eggs 

 microscopic to visible, and testes pinkish to flesh- 

 colored or wliite and slightly distended. None liad 

 gonads that would produce milt or eggs wlien 



pressed (stage 4 or 5) . Because the examination of 

 scales showed that most fish under about 110 mm. 

 were in their first year of life, it is likely that some 

 0-group fish and all yearling pinfish spawn. 



Eight pinfish 111 to 152 mm. long had ovaries 

 with eggs that were mature enough for counting; 

 eggs in smaller fish were too small to count accu- 

 rately. Tlie diameters of eggs were 0.09 to 0.66 mm. 

 (average 0.38) and the estimated numbers of eggs 

 were 7,700 to 39,200 (average 21,600). Caldwell 

 (1957) examined a pinfish 157 mm. long which 

 had an estimated 90,000 eggs that averaged about 

 0.5 mm. in diameter. 



ABUNDANCE AT THE SAMPLING STATIONS 



Pinfish are present in moderate numbers in the 

 deejier parts of Pensacola Bay in the summer; 

 they are most abundant in the southern part of the 

 estuary in extensive flats covered witli turtle grass. 

 Reid (1954) and Kilby (1955) also observed that 

 l)infish were most numerous in vegetation along 

 the Gulf Coast of Florida. Pinfisli are distributed 

 unevenly on the flats, as they tend to aggregate in 

 response to tlie environment — concentrations of 

 food especially attract them. 



Despite the wide confidence limits on the average 

 number of fish caught, sea.sonal trends are clearly 

 evident ( table 4) . Because the periods of maximum 

 and minimum al»undanc<>, and monthly changes in 



Tablk 4. — Pinfish caught per 15-minuie trawl-haul in the lower Pensacola Estuary, 1963-66 ' 



' 30 trawl-hauls wore made at each station on each visit, with the following exceptions {number of hauls in parentheses): Aug. 30-Sept. 6, 1963— station I (16), 

 station 11 (10); Jan. 12, Mar. 3, and Mar. 29, 1966— each station (6). 

 ' Less than 0.6. 



LIFE HISTORIES OF PINFISH AND ATLANTIC CROAKER 



141 



