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The Atlantic brief squid. Lolliguncula brevis, is a euryhaline cephalopod that inhabits shallow, continental shelf habitats from Argentina to the Bay of Fundy. In the southeastern United States, brief squid can account for a considerable portion of the estuarine animal biomass and are an important component of the diets of species with high priority for management and conservation. Historical data from South Carolina Department of Natural Resources suggest that brief squid exhibit spatially and temporally variable size-frequency distributions within the Charleston Harbor estuary. Prior to this study, however, detailed life history information for this species was lacking in the region. Samples of brief squid were collected monthly at four stations along a salinity gradient within the Charleston Harbor estuary in 2019 to investigate temporal and spatial patterns of abundance, sex, size, and maturity. Season and station were significantly related to brief squid abundance, which was greater for all sexes in spring, summer, and fall than in winter. Catches of brief squid were dominated by immature squid compared with mature squid. Excluding sexually indistinct squid, and across all seasons, significantly more males were collected than females. Mean brief squid size tended to be larger in May than in several other months of the year, largely due to the lower abundance of small squid in that month. Logistic regression analyses indicated that brief squid size-at-maturity occurred at 50.2 mm for males and 59.2 mm for females. The presence of both small and large brief squid throughout the year at all stations supports a pattern of overlapping cohorts, whereas the continual presence of immature brief squid at all stations suggests asynchronous recruitment. This study provides valuable life history information that can be used to support the conservation and management of organisms that are either prey or predators of brief squid within the Charleston Harbor estuary. Further research over multiple years and within other estuaries in the Georgia Bight is needed, however, to determine how the life history patterns observed in this study apply more broadly across the region. KEY WORDS: asynchronous, cohort, demographics, phenology, recruitment, Lolliguncula brevis, INTRODUCTION The life history of a population of organisms is defined by how resources are traded off and invested in anatomical, physiological. or behavioral traits that influence patterns of survival [...]

Sharks are essential components of marine communities, and their removal might simplify ecosystems and lead to unpredictable and detrimental effects on the food web. Comparing the isotopic niche of species between archaeological and modern communities can provide information to assess temporal changes in the ecological dynamics of communities. Here, stable isotope analysis was used to compare food web topology metrics between two shark guilds or communities, a late Holocene archaeological community (AC) dating from 700 to 500 years ago and a modern community (MC) trophic web, both from South Brazil. In the same line of comparison, we assess the trophic position of a top predator, Carcharias taurus. Results showed topological temporal differences such as higher trophic redundancy and higher patterns of niche overlap in the AC. Higher trophic redundancy could be expected in late Holocene food webs, as similar studies also observed these findings. In contrast, the MC showed less dense packing of species within the isotopic niche space, thus higher niche partitioning and higher trophic diversity, suggesting changing ecological interaction dynamics. We found that Carcharias taurus has increased its trophic level, possibly due to a release from the intraspecific competition and a dietary shift towards larger prey items. We suggest that anthropic impacts, such as overfishing, may cause these differences in the trophic position of this species. We also advocate that this study method might help future trophic reconstructions using shark teeth, as information about past marine environments is scarce, and could serve as a baseline for future studies., Author(s): Guilherme Burg Mayer [sup.1] [sup.2] , Renato Hajenius Aché de Freitas [sup.2] Author Affiliations: (1) grid.411237.2, 0000 0001 2188 7235, Programa de Pós-Graduação em Ecologia, Departamento de Ecologia e [...]