Potential predation rates by the sea stars Asterias rubens and Marthasterias glacialis, on juvenile scallops, Pecten maximus, ready for sea ranching

Abstract

The potential for predation by the sea stars Asterias rubens and Marthasterias glacialis on seed-size (41 ± 3 mm shell height) juvenile scallops (Pecten maximus), ready for seeding in sea ranching areas, was investigated in a 30-day laboratory predation experiment. There was no significant difference (P [ 0.05) in predation rate of large A. rubens (95-115 mm radium) and large M. glacialis (120-164 mm radius), which averaged 0.88 and 0.71 scallops individual -1 day -1 , respectively. Maximum rates of predation were 2.44 scallops individual -1 day -1 for large A. rubens and 3.00 scallops individual -1 day -1 for large M. glacialis. Small M. glacialis (76-87 mm radius) had a significantly lower predation rate than large individuals of either species (average 0.13 scallops individual -1 day -1 , P \ 0.05). Small A. rubens (50-80 mm radius) only began to prey on scallops when average scallop size was reduced to 35 mm. Based on estimated density of sea stars at a Norwegian sea ranching site and average predation rates, a population of scallops seeded at 10 m -2 would be reduced by between 0.5 and 11% in 1 month. Furthermore, using the highest observed predation rate, the degree of loss of scallops indicated that scallop culture via sea ranching would not be economically viable and thus methods for reducing scallop predation by sea stars are necessary.

Discovery of a novel neurophysin-associated neuropeptide that triggers cardiac stomach contraction and retraction in starfish

“…The feeding behaviour of starfish species such as A. rubens has an economic impact in terms of predation on shellfish that are harvested as foodstuffs (Aguera et al, 2012;Dare, 1982;Dolmer, 1998;Magnesen and Redmond, 2012). Furthermore, other starfish species such as the crown-ofthorns starfish, Acanthaster planci, feed on reef-building corals, and periodic increases in the population density of this species cause massive destruction of Pacific reef tracts (De'ath et al, 2012;Kayal et al, 2012;Timmers et al, 2012).…”

Predatory behavior of the sea stars <i>Asterias amurensis</i> and <i>Distolasterias nipon</i> on the Japanese scallop, <i>Mizuhopecten yessoensis</i>

“…In this cyclic culture, the scallops are composed of individuals from a single year class with little size differences within each area. The minimization of the risk of predation by considering the sizes of both the scallops and sea stars has been suggested in other species of scallops and sea stars (Barbeau et al 1996, Magnesen & Redmond 2012. We can recognize the density of all sea stars as a potential predator in each area from the relationships shown in Fig.…”

“…As the Japanese scallop grows larger than other sea star prey such as clams and mussels, the value of scallops as prey for sea stars may depend on their relative sizes. Indeed, sizedependent predation by sea stars is also known in other scallop species that grow to large sizes , Arsenault & Himmelman 1996, Magnesen & Redmond 2012. The assumption that all sea stars can consume all scallops would oversimplify their actual relationship.…”

Aquaculture of the sand star, Astropecten indicus Döderlein, 1888, as a step toward the sustainable aquaculture of harlequin shrimp, Hymenocera picta Dana, 1852

“…While there have been several studies that have established research aquarium‐based populations of sea stars, providing insights into the pest management of particularly problematic species, such as the crown‐of‐thorns starfish, Acanthaster planci (L.), and their role in the degradation of coral reefs throughout the Pacific (Baird, Pratchett, Hoey, Herdiana, & Campbell, ; Kayal et al, ; Keesing, ; Moran, ; Olson, ; Seto, ; Shibata, ; Tian, ), other studies have looked at the impact of sea star species on commercial mollusc culture. Studies, for example, include those on the 11‐armed sea star, Coscinasterias muricata Verrill, 1867 on New Zealand green‐lipped mussels, Perna canaliculus Gmelin, 1791 (see Inglis & Gust, ); Asterias vulgaris L. on the scallop, Pecten maximus (L., 1758) (see Barkhouse, Niles, & Davidson, ); Asterias rubens L. on mussels, Mytilus edulis l. (see Dare, ; Gallagher, Richardson, Seed, & Jones, ); on the Iceland scallop, Chlamys islandica (Muller, 1776) (see Brun, ); and together with Marthasterias glacialis (L., 1758) on juvenile P. maximus (see Magnesen & Redmond, ). The current study, however, represents the first aquaculture of a sea star species as a means of providing a sustainable supply of live feed for cultured harlequin shrimp.…”