The Behavior of Heterotypic Resting Schools of Juvenile Grunts (Pomadasyidae)

Resting schools of juvenile grunts (less than 12 cm length), composed primarily of Haemulon flavolineatum and H. plumieri, were studied from 1972 to 1976 on a series of patch reefs surrounded by seagrass beds on the northeast coast of St. Croix, U.S. Virgin Islands. Juvenile grunts form large inactive multispecies schools in reef areas by day. Repeated censuses over several years reveal that certain parts of the reef, particularly those with large formations of the corals Porites porites and Acropora palmata, are traditional schooling areas. When the fishes reach a size of about 15 cm, the H. plumieri form homotypic schools which roam the patch reefs but are no longer associated with particular formations of coral. In contrast, larger H. flavolineatum are uncommon on the patch reefs and they may move offshore to deeper water. The schools of juvenile grunts migrate some distance away (often 100 to 300 m) into seagrass-covered areas to feed on invertebrates at dusk each day. The routes which are followed into the seagrass beds are precise and persist over years. At dawn the grunts return to the reef on the same routes. Mass marking and release experiments show that juvenile grunts will move over long distances (approximately 3 km) to reach a home reef

Reproduction of a South American population of pumpkinseed sunfish Lepomis gibbosus (Linnaeus) (Osteichthyes, Centrarchidae): a comparison with the European and North American populations

The reproductive biology of the introduced pumpkinseed sunfish Lepomis gibbosus (Linnaeus, 1758) in the Custódio's Dam, rio Doce high basin, state of Minas Gerais, Brazil was studied from February/2001 to March/2002 and compared with introduced and native populations. Reproduction occurred almost along the entire period of study with a high frequency of fishes in the advanced ripening/mature and spawned/spent stages. The microscopic analyses indicated that the pumpkinseed sunfish presents multiple spawning. The egg diameter of the Brazilian population is similar to the Spanish, Greek and American ones. The standard length at maturity and the gonadosomatic index of the introduced populations are smaller when compared with native ones. The spawning season of the Brazilian population was the longest among all comparisons made in the present work.<br>Estudou-se de fevereiro/2001 a março/2002 a biologia reprodutiva da exótica perca-sol Lepomis gibbosus (Linnaeus, 1758) na represa do Custódio, bacia do alto rio Doce, Brasil, comparando-a à de populações exóticas e nativas. A reprodução ocorreu praticamente ao longo de todo o período de estudo e a análise microscópica de ovários indicou desova do tipo parcelada para a espécie. O diâmetro ovocitário da população brasileira é semelhante à espanhola, grega e americana. O comprimento padrão na maturidade e o índice gonadossomático de populações introduzidas são menores do que as nativas. O período de desova da população brasileira foi o maior dentre todas as populações analisadas no presente trabalho