Life History Studies Of The Alabama Shad, Alosa Alabamae, In The Apalachicola River, Florida

Since information on the biology of the Alabama shad, Alosa alabamae, of the Gulf coast of the United States is almost nonexistent, a study was initiated in February, 1966. Adult shad were collected on their spawning run in the Apalachicola River system, Florida, from February to April. Interpretation of the scale structure indicated that four age classes were represented. A few one-year-old males (average 10.6 inches TL) were in evidence in the latter part of the run. The two-year class consisted mostly of males (average 13.4 inches TL), and small numbers of females (average 14.5 inches TL). Three-year-old fish were most abundant; males (average 14.4 inches TL) and females (average 15.3 inches TL) were found in equal numbers. Small numbers of four-year-oIds were taken; most were females (average 16.1 inches TL) and a few were males (average 15.1 inches TL). No specimens more than four years old were collected. Preliminary indications are that one-, two-, and three-year-old males, and two-, and three-year-old females may return to spawn the following year. The adult fish entered the river in mid or late February and attained peak numbers in late April. A gradual ripening of the gonads was observed until the water temperature reached 20°C in late April, at which time spawning took place abruptly. Egg counts in ovaries ranged from 40,000 to 150,000. Food habit studies based on stomach analyses reveal that the adults take little or no food, and that juveniles feed largely on small fishes and aquatic dipterans. Growth and movements of juveniles were followed from June to September. Two distinct size groups of juveniles collected from the lower reaches of the river indicate that spawning takes place in at least two different areas in the drainage system.

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