Solaster endeca

Abstract: Biological traits of the sea cucumber Cucumaria frondosa (Gunnerus) relevant to both ecological and management perspectives were investigated in the Newfoundland region. Abundance, size and fitness of adults were maximal on hard substrates. Larvae settled ∼5 weeks post-spawning and juveniles reached a maximum length of 6 mm after 24 months. Additional size classes of sea cucumbers kept under natural environmental conditions exhibited slow seasonal growth attuned to phytoplankton blooms, indicating that ∼25 years may be required to reach market size. Juveniles of the predator sea star Solaster endeca (L.) readily fed upon 1.5-2 mm long sea cucumbers. Predation rates on adult C. frondosa by adult S. endeca were modulated by temperature and biased towards injured specimens, suggesting that trawling may exacerbate predation pressure. The combination of slow growth and high predatory pressure enhanced by fishing activities emphasises the need for precautionary management of this emerging fishery in Atlantic Canada.

Abstract: A study of behaviour of certain organisms displaying avoidance reactions to sea stars was part of an investigation to determine the substances responsible for such reactions. Research during 1964–65 in Scandinavian and British coastal areas focused on the reactions of 13 gastropod molluscs, 3 lamellibranch molluscs and 1 sea star following asteroid contact and suggested the possible adaptive significance of these responses. Sea stars used were Marthasterias glacialis, Asterias rubens, Crossaster papposus, Solaster endeca, and Asterina gibbosa. Although most recorded observations have been from temperate waters, a few observations suggest that avoidance behaviour to sea-star presence or contact is a world-wide phenomenon. Types of movements resulting from asteroid contact varied, but similarities were detected in related genera.

Abstract: The distribution and abundance of benthic megatauna in areas known to be inhabited by dense gorgonian coral assemblages were examined at Northeast Channel, off Nova Scotia, Canada, in August 2001. Using a remotely operated vehicle, 1 5 video transects during each of 1-2 dives at each of four sites (Rips, Middle Canyon, Hell Hole West and Hell Hole East) were conducted. The relationships in the structure of biological assemblages at three spatial scales: within transects (10s of metres); between dive locations (100s of metres); and among sites (10s to 100s of kilometres) were explored. The most abundant epibenthic taxa included the gorgonians Primnoa resedaeformis and Paragorgia arborea, several suspension feeders (Actinauge verrilli, Bolocera tudiae, an unidentified anemone and encrusting sponge, Ophiacantha abyssicola), the deposit feeder Porania pulvillus insignus and the predatory Solaster endeca. The basket star Gorgonocephalus arcticus was present only on colonies of Paragorgia arborea. Despite large variability in abundance and assemblage composition among transects and dive locations, clear patterns were observed among sites. Mean abundance of most cnidarians and echinoderms was greatest at Hell Hole West. No gorgonians were found at Hell Hole East. The encrusting sponge was most abundant at the Rips and least abundant at Hell Hole East. Cluster analysis and multidimensional sealing (MDS) indicated that, when abundance was averaged across transects for each dive, the megafaunal assemblages fall into groups of dives that separated by site. These differences, among sites are most likely related to variability in the physical environment. The epibenthic megafaunal assemblages were as diverse in the presence as in the absence of gorgonian corals, at least at the abundances that we observed. However, the apparent low recruitment and abundance, combined with small population size make these assemblages particularly vulnerable to perturbations.