Comparison of spawning seasons, age, growth rates, and food of two sympatric species of searobins, Prionotus carolinus and Prionotus evolans, from Long Island Sound
Prionotus carolinus and Prionotus evolans were collected from many locations within Long Island Sound in 1971–1973, and in 1976–1977. Data from earlier collections in Block Island Sound (1943–1945) were also included. A total of 1751 specimens, 960 P. carolinus and 791 P. evolans was examined within these two time periods.
Both species entered the Sound in April and spawned during June and July. P. evolans appeared to spawn slightly earlier in summer than P. carolinus. Adults began to leave the Sound after spawning and were usually absent after November. Young-of-the-year were taken regularly from August to November and, occasionally in water over 20 m deep, into February when the bottom water temperature was 1.4°C. At the end of the first growing seasons both species exhibited large variations in standard lengths.
Back-calculations from scale annuli measurements indicated that linear growth rates during the juvenile years were similar in both species. However, P. evolans was considerably heavier than P. carolinus. During adulthood P. evolans was not only longer and heavier than P. carolinus, but lived longer. Growth rates are described by the following equations: P. carolinus Lt+1=9.60+0.68 (Lt), and p. evolans Lt+1=7.70+0.80 (Lt).
Both species were opportunistic feeders, and crustaceans were clearly the dominant group of prey. Young-of-the-year, between 3–6 cm, ate copepods. As they grew they ate larger prey, such as Neomysis americana, Diastylis quadrispinosus, various species of amphipods of small sizes, and juvenile Crangon septemspinosus. Older fish ate larger sizes of these same prey, a number of species of crabs, juvenile Homarus americanus, and Squilla empusa. Occasionally they ate polychaetes, molluscs, and juvenile fish.
Partitioning of the resources of Long Island Sound by these two species appeared to be by prey size. P. evolans ate prey that, on the average, were slightly larger than those eaten by P. carolinus. Furthermore, P. evolans ate a greater amount of nektonic species than P. carolinus, which appeared to prefer benthonic invertebrates.
- Austin, H. M., J. Dickinson, and D. Hickey. 1973. An ecological study of the ichthyofauna at the Long Island Light Company (LILCO) fossil fuel power generating facility at Northport, Long Island, new York, 1972. Fish. oceanogr. Dept. N.Y. Ocean Sci. Lab. (NYOSL). Final report, contract no. SR72-23F:248 p.Google Scholar
- Lewis, T. C., and R. W. Yerger. 1976. Biology of five species of searobins (Pisces, Triglidae) from the Northeastern Gulf of Mexico. Fish. Bull. 74 (1):93–103.Google Scholar
- Mann, J. M. 1974. Some aspects of the biology of the searobins Prionotus carolinus and Prionotus evolans. Unpublished Master of Science Thesis, Long Island University.Google Scholar
- Merriman, D., and H. E. Warfel. 1948. Studies on the marine resources of southern New England. VII. Analysis of a fish population. Bull. Bingham Oceanogr. Coll. 11 (4):131–164.Google Scholar
- Perlmutter, A. 1939. A biological survey of the salt waters of Long Island. 1938. Section I. An ecological survey of young fish and eggs identified from tow-net collections. Suppl. 28th Ann. Rep. N.Y. Cons. Dept., Pt. II:11–71.Google Scholar
- Richards, S. W. 1959. Oceanography of Long Island Sound. Pelagic fish eggs and larvae. Bull. Bingham Oceanogr. Coll., 17 (1):95–124.Google Scholar
- — 1963. The demersal fish population of Long Island Sound. I. Species composition and relative abundance in two localities, 1956–57: 5–31. II. Food of the juveniles from a sand-shell locality (Station I): 32–72. III. Food of the juveniles from a mud locality (Station 3A): 73–101. Bull. Bingh. Oceanogr. Coll. 18 (2):5–101.Google Scholar
- —, And G. A. Riley, 1967. The benthic epifauna of Long Island Sound. Bull. Bingh. Oceanogr. Coll. 19: 89–135.Google Scholar
- — 1978. Trophic ontogeny of the leopard searobin, Prionotus scitulus (Pisces: Triglidae). Fish. Bull. 76: 225–234.Google Scholar
- Thomson, K. S., W. H. Weed III, and A. G. Taruski. 1971. Saltwater fishes of Connecticut. State Geol. Nat. Hist. Surv. Conn., Bulletin No. 105:165 p.Google Scholar
- Warfel, H. E., and D. Merriman. 1944. Studies on the marine resources of southern New England. I. An analysis of the fish population of the shore zone. Bull. Bingh. Oceanogr. Coll. 9 (2):1–91.Google Scholar
- Wheatland, S. B. 1956. Oceanography of Long Island Sound, 1952–1954. VII. Pelagic fish eggs and larvae. Bull. Bingh. Oceanogr. Coll. 15:234–314.Google Scholar