Common snook Centropomus undecimaliswere sampled monthly from the Jupiter–Lake Worth area of Florida's Atlantic coast during 1989 and 1991 (1452 fish) and from Tampa Bay on Florida's Gulf of Mexico coast during 1988 and 1989 (2090 fish). Group‐synchronous oocyte development was demonstrated. Ovarian maturation began during March or April on both coasts. Spawning was first detected histologically in April during 1989 and 1991 on the Atlantic coast and during May in 1988 and in April in 1989 on the Gulf coast. In each year, spawning ended during October on the Atlantic coast and during September on the Gulf coast. Ovarian histological evidence suggested that individual females may spawn every 1·1–2·5 days between 1400 and about 2000 hours. Final oocyte maturation occurred independently of either tidal cycle or lunar phase, and some common snook were observed in prespawning or spawning condition on every day sampled. Spawning occurred in or near major inlets to the Atlantic Ocean and the Gulf of Mexico, in secondary passes to larger inland bays and bayous, and around nearshore islands.

During the annual reproductive cycle, the lobular testis of Centropomus undecimalis undergoes height, width, and morphological changes which reflect five reproductive classes: regressed; early, mid-, and late maturation; and regression. Histological criteria, particularly differences between continuous and discontinuous germinal epithelia, are used to distinguish these five classes, even though they are only reference points within the annual gonadal cycle. A mechanism for lobular growth during early, mid-, and late maturation is presented; and it is hypothesized that a permanent germinal epithelium first appeared in the fishes. Throughout the year, periodic acid-Schiff-positive macro-melanophage centres and PAS-positive granulocytes are observed in the testis. They are most abundant after the breeding season, and they may be involved in focal tissue degradation. 1998 The Fisheries Society of the British Isles

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Estimates of age, growth, and mortality of spotted seatrout Cynoscion nehulosus were made by analyzing fish from commercial and recreational catches in 1986-1988 in three estuarine areas of Florida: Apalachicola Bay, Charlotte Harbor, and Indian River Lagoon. Thin sections of sagittae were used to determine age: annulus formation occurred in November-May. The maximum observed age differed among areas, ranging from 5 to 9 years for males and from 6 to 8 years for females. Spotted seatrout reached 301-337 mm total length at the end of their first year. Females were generally larger at age than males, although growth was highly variable. After age 1, male growth slowed to an average of 34-51 mm/year and was modeled best by area-specific linear growth equations. Females showed asymptotic growth that slowed from 87-107 mm at ages 1-2 to 46-60 mm at ages 4-5 and that was modeled best by area-specific Gompertz growth equations. Males and females from Indian River Lagoon and Apalachicola Bay were generally larger than those from Charlotte Harbor. Males were heavier than females of the same length. Estimates of total annual mortality were 48-76% in 1986-1988 and seemed highest in Apalachicola Bay. Patterns of growth did not reflect those previously used to support hypothesized divisions of spotted seatrout into separate subpopulations in Florida estuaries. Differences in growth and age composition observed among estuaries may reflect differences in environmental and fishing effects rather than genetic differentiation among estuaries. MethodsSpotted seatrout were sampled monthly from commercial and recreational catches during

The ecology of common snook Centropomus undecimalis in Amatique Bay, a tropical estuary in eastern Guatemala, was investigated and life-history traits were used to conduct a meta-analysis of the species from Florida to Brazil. The reproduction cycle of C. undecimalis in Amatique was strongly related to the precipitation cycle, with a lag of 2 months. Spawning occurred from April to November with a peak spawning after the onset of the summer rains. Protandric sex reversal occurred early in the dry season (December) before somatic recovery from spawning. The growth cycle preceded that of body condition by c. 1 month, and was out of phase with the reproductive cycle. Growth was fast, as many individuals reached >70% of the maximum observed total length (LT , 102 cm) after 3 years. Sex transition occurred within a relatively narrow LT range (70-79 cm), but over a wide range of ages, indicating plasticity in this respect. The meta-analysis indicated a latitudinal-temperature gradient in life-history traits, as well as different seasonal patterns relative to temperature and hydrographical cycles. Centropomus undecimalis from cooler winter waters (e.g. Florida) reach larger maximum LT and LT at sex change, as well as greater gonado-somatic indices and longer life spans. Further, increased fishing mortality results in younger age at sex reversal and male predominance in the populations compared. Recognition of large-scale biogeographic patterns in this important, but little studied, fish species helps in the formulation of management advice in other areas of its occurrence.