Can an emblematic species become a pest? The case of Astrospartus mediterraneus (Risso, 1826) (Echinodermata: Ophiuroidea) in the artisanal fishing grounds of the Cap de Creus area (NW Mediterranean Sea)

4th Mediterranean Symposium on the Conservation of Coralligenous & other Calcareous Bio-Concretions, 20-21 September 2022, Genoa, Italy.-- 6 pages, 2 figures

Astrospartus mediterraneus (Risso, 1826) (Echinodermata: Ophiuroidea) is an emblematic Mediterranean species yet, it has few reports and hasn’t received much attention from the marine scientific community to date. In the framework of a project to assess how to mitigate the impact of artisanal fishing on benthic communities at the Site of Community Importance (SCI) of Cap de Creus (NW Mediterranean) (MITICAP Project), an unusually high abundance of the basket star (A. mediterraneus) was observed in 2018 as part of the by-catch of the local artisanal fishers. Indeed, the fishers involved in the project reported that this species had increased in abundance and expanded its distribution over the past years, ultimately interfering with their fishing activity. This work benefits from the Local Ecological Knowledge of the fishers, analyses field surveys and aims to elucidate the abundance, distribution, size, and structure of A. mediterraneus populations; as well as to examine the possible impact this species has on the artisanal fisheries performance. Data collection was performed through bycatch photo analysis of regular fishing events from May to August, analysis of video-transects recorded by means of Remote Operated Vehicles and conducting interviews with fishers to identify the impact. Basket stars were associated with rocky substrates with presence of gorgonians located between 50 to 80 m depth, preferentially occurring on sloping areas. Despite their high abundances (0.45±0.71 ind/m2), the aggregations witnessed in the Cap de Creus area could not be determined as an outbreak due to the lack of longtime monitoring data thus, yet it seems apparent based on the LEK of the fishers that the species has been on the rise for the past years and they unanimously consider that its proliferation causes them a handicap in terms of monetary and time losses

Their work was performed under the MitiCap and ResCap projects, which are founded by the Fundación Biodiversidad from the Ministerio para la Transición Ecológica, through the Pleamar Program, co-funded by the European Maritime and Fisheries Fund

Peer reviewed