Common starfish

Abstract: Mussel cultivation is the most valuable sector of the bivalve aquaculture industry in the United Kingdom, and the largest mussel fishery in Britain is located in the Menai Strait, North Wales. The common starfish, Asterias rubens is highly abundant and widely distributed throughout British waters, affecting the distribution and abundance of prey species such as the common mussel, Mytilus edulis. This study investigates the potential influence of the Menai Strait mussel fishery on seasonal patterns of abundance, distribution, and migration of A. rubens, and aspects of their reproductive strategy. Starfish and mussel populations were surveyed and sampled monthly over a 2-y period using a visual survey technique and by trawling the seabed during the mussel harvest period. Maximum starfish density (40,586 ± 5,648 starfish·ha−1) and percentage mussel coverage (∼40%) were recorded on a commercial subtidal mussel bed. Mussel density and starfish abundance increased seasonally between April and July and ...

Abstract: During diving surveys for a Russian research project that monitored introduced species, red king crabs (Paralithodes camtschaticus) were collected at a coastal site of the Barents Sea to study the structure and dynamics of this species. Sampling of the organisms colonizing the crabs was part of this research project. For the first time, the presence of relatively large specimens of the common starfish Asterias rubens as epibionts of P. camtschaticus was observed in July 2010, 2018, and 2019. In 2010 and 2019, we also found three other echinoderm species (the Atlantic sea cucumber Cucumaria frondosa, the green sea urchin Strongylocentrotus droebachiensis, and the brittle star Ophiura sarsii). These findings add to the current list of associated species on king crabs not only in the Barents Sea but also in native areas of this host. Red king crabs have been documented as predators for these echinoderm species, and our records show additional possible interactions between king crabs and echinoderms in this region. More likely, the epibiotic lifestyle allows these echinoderms to avoid predation from red king crabs. There are no potential disadvantages derived by red king crabs through their relationships with the echinoderm epibionts due to low occurrences of these associations. We suggest no negative effects for the local red king crab population and populations of other commercial species in the Barents Sea.

Abstract: The general biology of the common starfish, Asterias rubens L., has recently been studied by Vevers (1949), whose investigations included observations on the growth-rate of this species. His material was collected in the Plymouth area largely by means of an otter trawl, supplemented by a few Agassiz and dredge hauls, and there are therefore few records in his data of the growth-rate of juvenile A. rubens under natural conditions. Vevers also made observations on the growth-rate of individuals kept in laboratory tanks, but again the results apply mainly to fairly large animals. The only other direct observations on growth-rate appear to be those of Bull (1934), who dealt with three small individuals kept in aquarium tanks, while Orton & Fraser (1930) give measurements made on a natural population taken, after one year's growth, from a buoy.