Research Product

The abundance, growth, age composition, food, migration, and reproduction of the two species were studied at two locations for each species from August 1963 to December 1965. The materials comprised 22 fish collections at each station, taken in about 500 hours of trawling. The stomach contents of 3,577 pinfish and 2,520 Atlantic croakers indicated that pinfish are omnivorous and croakers carnivorous. Principal foods were vegetation, crustaceans, and polychaetes for pinfish and annelids, fish, and arthropods for croakers. Types of food in pinfish stomachs were similar at all sizes and seasons, but the relative amount of each type differed by season and size of fish. Foods in croaker stomachs differed at the two stations but were similar from year to year. The average food volume in the stomachs varied with time of year, location, and fish size. Volumes of food in stomachs of both species decreased when the fish moved from the estuary. Length-frequency distributions can be used to estimate age in both species. Pinfish, and possibly croakers, form annuli on their scales. Growth of pinfish and Atlantic croaker varied from year to year. Some fish of both species had developing gonads in the fall of their first year of life and may spawn. Both species migrate offshore in the fall to spawn. The fry and some adults return to the estuary in the winter and spring. Abundance of pinfish and Atlantic croakers was highest in late spring and early summer. Pinfish at both stations and croakers at one station were less abundant in 1964 than in 1963 or 1965. Yearly differences in abundance of croakers were not large at the other location.