A historical appraisal of fish assemblage and the artisanal fishery in San Antonio Bay, northern Patagonia, Argentina

For nearly a century, the artisanal fishery in San Antonio Bay, northern Patagonia, has relied on habitats crucial for fish spawning, nursery, and feeding. This study characterizes the composition and temporal dynamics of the coastal fish assemblage and evaluates its relationship with the artisanal fishery by comparing current findings with historical records. Sampling was conducted bi-monthly over two annual cycles in traditional fishing grounds. The abundance and biomass of each captured species were quantified and standardized per haul based on the area swept by the net. Of the 17 fish species identified, Odontesthes argentinensis was the most abundant while Eleginops maclovinus was the most represented in terms of biomass. While biomass remained constant, a significant seasonal effect was observed in fish abundance, which increased during the warmer months. Compared to 1990s records, species composition and dominance shifted, particularly with the replacement of O. platensis by O. argentinensis. Additionally, current data revealed a higher prevalence of juvenile individuals, and a lower occurrence of large fish compared to historical observations. Target species have remained relatively consistent since the early years of fishery activity, and overall fishing capacity has increased in the past decade. Yet, catch volumes are at their lowest point. Changes in fish species dominance in the SAB assemblage may stem from population cycles, and climate change, while the decline of the fish landings relates to socioeconomic factors. Long-term monitoring of coastal fish assemblage dynamics is essential for effective management of this artisanal fishery.