Abstract
During 1976 and 1977, movements and foraging activities of Pempheris schomburgki were studied on the shallow coral reefs of northeastern St. Croix, U.S. Virgin Islands. P. schomburgki emerge from daytime refuges on the backreef at about local sunset. Fifteen to 20 min after sunset, local milling groups move beyond the confines of the reef and assemble into larger groups. Twenty-five to 30 min after sunset they move in several waves along complex routes through the reef to forereef feeding grounds. Migrations of up to 1 km occur along the forereef. The reverse sequence occurs in the morning, but is earlier with respect to ambient light levels. The principal stages of these activities appear to be triggered by a combination of absolute light level, rate of change of light and state of adaptation of the eye. Migrating aggregations gradually split up into small, well-dispersed feeding groups, relatively evenly spaced along the forereef. Few individuals feed on the backreef. The principal available food consists of meroplanktonic crustaceans not available during the daytime. P. schomburgki mainly select the larger-sized individuals (mean length 5 to 6 mm), although some particles less than 1 mm are taken. These events probably represent adaptations to optimize diurnal sheltering sites, feeding grounds and the avoidance of predator activity.
Similar content being viewed by others
Literature cited
Alldredge, A.L. and J.M. King: Distribution, abundance, and substrate preferences of demersal reef zooplankton at Lizard Island Lagoon, Great Barrier Reef. Mar. Biol. 41, 317–333 (1977)
Bardach, J.E.: On the movements of certain Bermuda reef fishes. Ecology 39, 139–146 (1958)
Collette, B.B. and F.H. Talbot: Activity patterns of coral reef fishes with emphasis on nocturnal-diurnal changeover Sci. Bull. nat. Hist. Mus. Los Ang. Cty 14, 98–124 (1972)
Davis, W.P. and R.S. Birdsong: Coral reef fishes which forage in the water column. Helgoländer wiss. Meeresunters. 24, 292–306 (1973)
Domm, S.B. and A.J. Domm: The sequence of appearance at dawn and disappearance at dusk of some coral reef fishes. Pacif. Sci. 27, 128–135 (1973)
Emery, A.R.: Preliminary observations on coral reef plankton. Limnol. Oceanogr. 13, 293–303 (1968)
Fishelson, L., D. Popper and N. Gunderman: Diurnal cyclic behavior of Pempheris oualensis (Pempheridae, Teleostei). J. nat. Hist. 5, 503–506 (1971)
Hiatt, R.W. and D.W. Strasburg: Ecological relationships of the fish fauna on coral reefs on the Marshall Islands. Ecol. Monogr. 30, 64–127 (1960)
Hobson, E.S.: Diurnal-nocturnal activity of some inshore fishes in the Gulf of California. Copeia 1965(3), 291–302 (1965)
—: Predatory behavior of some shore fishes in the Gulf of California. U.S. Bur. Sport. Fish Wildl. Res. Rep. 73, 1–92 (1968)
—: Activity of Hawaiian reef fishes during the evening and morning transitions between day-light and darkness. Fish. Bull. U.S. 70, 715–740 (1972)
—: Diel feeding migrations in tropical reef fishes. Helgoländer wiss. Meeresunters. 24, 361–370 (1973)
—: Feeding relationships of teleostean fishes on coral reefs in Kona, Hawaii. Fish. Bull. U.S. 72, 915–1031 (1974)
— and J.R. Chess: Feeding oriented movements of the atherinid fish Pranesus pinguis at Majuro Atoll, Marshall Islands. Fish. Bull. U.S. 71, 777–786 (1973)
——: Trophic interactions among fishes and zooplankters near shore at Santa Catalina Island, California. Fish. Bull. U.S. 74, 567–598 (1976)
——: Trophic relationships among fishes and plankton in the lagoon at Enewetak Atoll, Marshall Islands. Fish. Bull. U.S. 76, 133–153 (1978)
Jørgensen, C.B.: Biology of suspension feeding, 357 pp. Oxford: Pergamon Press 1966
Major, P.F.: Predator-prey interactions in schooling fishes during periods of twilight: a study of the silverside Pranesus insularum in Hawaii. Fish. Bull. U.S. 75, 415–426 (1977)
Munz, F.W. and W.N. McFarland: The significance of spectral position in the rhodopsins of tropical marine fishes. Vision Res. 13, 1829–1874 (1973)
Ogden, J.C. and N.S. Buckman: Movements, foraging groups and diurnal migrations of the striped parrotfish Scarus croicensis Block (Scaridae). Ecology 54, 589–596 (1973)
— and P.R. Ehrlich: The behavior of heterotypic resting schools of juvenile grunts (Pomadasyidae). Mar. Biol. 42, 273–280 (1977)
Porter, J.W. and K.G. Porter: Quantitative sampling of demersal plankton migrating from different coral reef substrates. Limnol. Oceanogr. 22, 553–556 (1977)
Randall, J.: Food habits of reef fishes of the West Indies. Stud. trop. Oceanogr., Miami 5, 665–847 (1967)
Sale, P.F., P.S. McWilliam and D.T. Anderson: Composition of the near-reef zooplankton at Heron Reef, Great Barrier Reef. Mar. Biol. 34, 59–66 (1976)
Starck, W.A. and W.P. Davis: Night habits of fishes of Alligator Reef, Florida. Ichthyologica 38, 313–356 (1966)
Author information
Authors and Affiliations
Additional information
Communicated by J.M. Lawrence, Tampa
Rights and permissions
About this article
Cite this article
Gladfelter, W.B. Twilight migrations and foraging activities of the copper sweeper Pempheris schomburgki (Teleostei: Pempheridae). Marine Biology 50, 109–119 (1979). https://doi.org/10.1007/BF00397815
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00397815