1. Temporal variation in the spatial aggregation of the freshwater bivalve Elliptio complanata was studied at a sandy site in an oligotrophic lake over three years. 2. Epibenthic populations varied in aggregation over the season bringing animals closer together during spawning. The complex link between movements of mussels and aggregation dynamics suggested a functional reproductive role for ho...

—We used an age-structured model to evaluate the impacts of recreational angling during spawning on populations of largemouth bass Micropterus salmoides and the potential benefits of seasonal fishing closures. We simulated fisheries with average and high capture rates (i.e., fractions of the stock caught by anglers). We manipulated mortality rates to mimic the effects of various regulations, in...

this study aimed to investigate the spawning season, length at first maturity (lm 50 ) and sex ratio of metapenaeus affinis in the shrimp fishing grounds of hormozgan province, west of the persian gulf, iran. samples were taken by the swept area method and trawl net with 2 cm mesh size in the cod end from january 2010 to february 2011. results showed that the sex ratio deviated from 1:1 and fem...

The interspawning interval, or spawning frequency, of wild three-spined stickleback, Gasterosteus aculeatus, was estimated using histological examination of postovulatory follicles (POF). Females in Alaskan lakes appeared to have as much as a 48 h delay between ovulation and ovoposition, yet the POF method could still be used to estimate the interspawning interval. In two Alaskan lakes the inte...

1. There are two prominent, nonmutually exclusive hypotheses to explain the timing of reproduction in animals: energetic constraint and adaptive behaviour. 2. We tested these hypotheses by quantifying the costs and benefits of nesting at different times in the season for male bluegill sunfish Lepomis macrochirus, a species with paternal care, in Lake Opinicon (Ontario, Canada). 3. The value of ...

During 12 months of sampling, from 17 stations, 327 specimens of Soboor fish Tenualosa ilisha, including 120 females, 113 males and 86 immature were caught. Total length (TL) of the fishes was 120-500mm. Maximum diameters of soboor ova 0.795mm and the ova with diameter more than 0.7 mm released at one spawning round. Temporal and spatial distribution of ova diameter corresponding to GSI changes...

Pituitary mRNA levels of gonadotropin β-subunits and of their cognate receptors in the testis were studied during puberty in Atlantic cod under normal and experimental photoperiod conditions that suppressed, delayed or accelerated testis maturation. Results are discussed in context with changes in testicular histology and plasma androgen levels, considered as end points of gonadotropic regulati...

Ultrasonic imaging was used to determine the spawning population structure and develop a fecundity estimation model for a red hind Epinephelus guttatus spawning aggregation within the Red Hind Bank Marine Conservation District, St Thomas, U.S.V.I. The spawning population showed considerable within-month and between-month variation in population sizeand sex-structure. In the spawning season stud...

The reproduction of two species of Cichla (Cichla cf. ocellaris and C. monoculus, commonly known in Brazil as tucunaré) introduced in the Volta Grande Reservoir, southeastern Brazil, was analyzed. The period for spawning began at the end of the dry season (September) and extended until the end of the rainy season (January). The length of the first gonad maturation (L50) and the length at which ...