Home range and seasonal movements of Black Sea Bass (Centropristis striata) during their inshore residency at a reef in the mid-Atlantic Bight

Black Sea Bass (Centropristis striata) in the mid-Atlantic Bight undertake seasonal cross-shelf movements to occupy inshore rocky reefs and hardbottom habitats between spring and fall. Shelf-wide migrations of this stock are well documented, but movements and home ranges of fish during their inshore residency period have not been described. We tagged 122 Black Sea Bass with acoustic transmitters at a mid-Atlantic reef to estimate home-range size and factors that influence movements (>400 m) at a 46.1-km2 study site between May and November 2003. Activity of Black Sea Bass was greatest and most consistent during summer but declined rapidly in September as water temperatures at the bottom of the seafloor increased on the inner shelf. Black Sea Bass maintained relatively large home ranges that were fish-size invariant but highly variable (13.7–736.4 ha), underscoring the importance of large sample sizes in examination of population-level characteristics of mobile species with complex social interactions. On the basis of observed variations in movement patterns and the size of home ranges, we postulate the existence of groups of conspecifics that exhibit similar space-use behaviors. The group of males released earlier in the tagging period used larger home ranges than the group of males released later in our study. In addition, mean activity levels and the probability of movement among acoustic stations varied among groups of fish in a complex manner that depended on sex. These differences in movement behaviors may increase the vulnerability of male fish to passive fishing gears, further exacerbating variation in exploitation rates for this species among reefs

Habitat associations and dispersal of black sea bass from a mid-Atlantic Bight reef

We examined habitat associations of 122 adult black sea bass Centropristis striata at a temperate reef off the coast of New Jersey, USA. The study site, located within the Historic Area Remediation Site, encompassed 46.1 km2 and included areas of rocky bottom and highly variable bathymetry. Factors influencing dispersal and habitat use were determined from acoustic tele - metry data collected between May and December 2003 from a grid of 72 moored receivers. About 2.7 times as many black sea bass used the site in summer as in fall. Fish were associated with relatively shallow, complex habitats characterized by previously placed, coarse-grain material that may have provided food, shelter, or both. Deep areas (\u3e27.5 m) with coarse-grain material were rarely used. Dispersal of black sea bass was not a pulse event, but rather a steady movement of individuals away from the site as inshore bottom water temperatures declined between late September and mid-December. Both temperature and photoperiod may serve as cues to the initiation of offshore movements of fish to wintering grounds near the edge of the shelf. Some black sea bass resided at the reef for periods of up to 6 mo encompassing the spawning period; as such, these habitats may be important to the continued production of the stock. In the mid-Atlantic Bight, surveys to estimate the relative abundance of this species during their inshore residency period should be conducted in July–August in structurally complex habitats and in waters \u3c28 m deep