Giant sea bass (Stereolepis gigas, Polyprionidae) are the largest reef-associated teleost in the northeastern Pacific, considered an important predator in Macrocystis kelp forest and rocky reef ecosystems. Because of the predictability of annual aggregations, giant sea bass (GSB) were fished throughout the twentieth century until they were nearly extirpated from southern California and Baja California, Mexico. To assess population recovery, acoustic telemetry was used to quantify spatiotemporal rhythmicity of GSB aggregations at Santa Catalina Island, California, USA. Thirty-two individuals were tracked for 498 days over two consecutive spawning seasons in 2017-2018 and visual surveys were conducted monthly to estimate aggregation sizes. Aggregation behavior was documented from June-October and spawning most likely occurred at a pinnacle promontory from July-September. GSB exhibited residency to specific sites throughout the year and individuals showed fidelity to suspected spawning aggregation sites during the summer months. Ten (31%) GSB were detected at Santa Catalina Island year-round and 11 (34%) exhibited suspected annual spawning site fidelity. Four individuals (12%) were documented leaving the island during late fall/winter 2017 and returning in spring/early summer 2018, indicating partial seasonal migration and year-round fidelity to specific sites at Santa Catalina Island. This study provides a baseline of spatiotemporal movements and behavioral patterns that can be used to improve our understanding of GSB and enhance management for these and other largebodied predatory fish species.

Many terrestrial and aquatic taxa are known to form periodic aggregations, whether across life history or solely during specific life stages, that are generally governed by the availability and distribution of resources. Associations between individuals during such aggregation events are considered random and not driven by social attraction or underlying community structure. White sharks (Carcharodon carcharias) have been described as a species that exhibits resource-driven aggregative behaviors across ontogenetic stages and juvenile white sharks are known to form aggregations at specific nursery sites where individuals may remain for extended periods of time in the presence of other individuals. We hypothesized juvenile white sharks form distinct communities during these critical early phases of ontogeny and discuss how a tendency to co-occur across life stages may be seeded by the formation of these communities in early ontogeny. We present results from a series of social network analyses of 86 juvenile white sharks derived from 6 years of passive acoustic telemetry data in southern California, demonstrating the likelihood of association of tagged juvenile white sharks is greater when sharks are of similar size-classes. Individuals in observed networks exhibited behaviors that best approximated fission-fusion dynamics with spatiotemporally unstable group membership. These results provide evidence of possible non-resource driven co-occurrence and community structure in juvenile white sharks during early life stages.

The giant sea bass Stereolepis gigas Ayres 1859 (GSB) is a critically endangered top marine predator in California. Since protection in 1982 and 1994, the population has appeared to increase, and individuals within a growing population may expand their ranges to new habitats to reduce intraspecific competition and increase foraging opportunities. In 2016-2018, two GSB tagged with acoustic transmitters were detected at artificial reefs for periods of up to 3 months during October-March, and one individual travelled 53 km from an offshore island to mainland California in 56 h. Artificial reefs may provide important foraging opportunities for these protected marine predators as they recover from exploitation. K E Y W O R D S acoustic telemetry, artificial reefs, giant sea bass, Stereolepis gigas, VPS, wastewater Giant sea bass Stereolepis gigas Ayres 1859 (GSB) are one of the few top predators resident to California kelp forest and rocky reef commu

Site fidelity and aggregation behaviour were assessed for giant sea bass Stereolepis gigas (GSB) at Santa Barbara Island, California, USA, from 2018 to 2020. Results indicate seasonal variation in GSB presence, and network analyses revealed a preferred location in a spatially constrained pattern, indicative of aggregation behaviour.Results show GSB aggregated annually during spawning months in the same location, confirming the first known aggregation of GSB at Santa Barbara Island. Identifying and monitoring aggregation sites is vital to ensuring proper protection and ultimate recovery for this protected species in a changing climate.