Reproduction, recruitment and juvenile ecology of the starfish,Asterias rubensandMarthasterias glacialis

Abstract

Reproductive cycles are described for subtidal and intertidal populations of the, starfishAsterias rubensL. and for a subtidal population of the starfishMarthasterias glacialisL. on the south-west coast of Britain. IntertidalA. rubenshad a clearly defined reproductive cycle with spring-early summer spawning. Pyloric caecum indices were inversely related to gonad indices. SubtidalA. rubenshad lower gonad indices and less seasonal variation in the pyloric caecum indices. Gonad indices ofM. glacialissuggest few animals in the population studied were breeding, but it is likely that this species also spawns in summer.Plankton samples and larval rearing studies suggest a planktotrophic pelagic life of approximately 90 days forA. rubens. Field observations and laboratory experiments show larvae settle on a wide range of substrata. Recruitment to an intertidal population ofA. rubensat Hollicombe Reef occurred in July 1980 and September 1981. Growth of juvenile starfish was followed for 17 months. Juvenile starfish feed carnivorously at the completion of metamorphosis. Early growth is rapid; however, there is a reduction in the growth rate during winter months. Feeding and growth of juvenileA. rubensis compared with published data on juvenile starfish of other species.

Phylogeography of the sea star Marthasterias glacialis (Asteroidea, Echinodermata): deep genetic divergence between mitochondrial lineages in the north-western mediterranean

“…Marthasterias glacialis (order Forcipulata, Asteriidae) is widely distributed in Europe, from Finnmark (the northernmost county of Norway) to the Mediterranean Sea (Harmelin et al 1980;Nichols and Barker 1984;Savy 1987), being a common and emblematic species at both sides of the Gibraltar Strait, predator of bivalves and other echinoderms (Barker and Nichols 1983;Frid 1992;Guidetti 2004). Despite its abundance in the North Atlantic sublittoral habitats, it is not, in general, abundant along the Mediterranean littoral, rarely reaching densities up to 2 ind/50 m 2 (Savy 1987).…”

“…M. glacialis is a broadcast spawner sea star, with long dispersal capability due to a planktotrophic larva, which remains in the water column for more than 3 months, passing through several larval stages. When adhesive structures appear, the larva attaches to the substrate and the metamorphosis commences (Barker and Nichols 1983).…”

Composition and vertical distribution of the motile epifauna on a vertical rock wall in Gullmarsfjorden, western Sweden, using an alternative sampling approach

“…They were most abundant at 2 and 6 m, but also occurred sparsely at deeper levels. Barker & Nichols (1983) found that juvenile A. rubens settled in late June or early July and that small numbers of starfish continued to settle in August and September. The decrease in number of starfish in September was probably due to juvenile mortality and, to some extent, migration out of the sampling area.…”

“…Juvenile A. rubens occurred mainly at shallow sites. They feed carnivorously immediately after completion of metamorphosis (Barker & Nichols 1983). The small starfish feeds primarily on young blue mussels, Mytilus edulis L. (Mortensen 1924), which are abundant among algae and hydroids in shallow areas (Jensen & Spärck 1934).…”

Cycle et comportement de reproduction du neogasteropode Buccinum undatum L dans le golfe Saint-Laurent

“…Lorsque la ponte a lieu, de la fin mal jusqu'à juillet-août, les poids moyens de l'ovaire et ( Farmanfarmaian et al, 1958;Mauzey, 1966;Barker et Nichols, 1983). Cest ce qui semble être le cas chez le buccin, qui se nourrit peu durant cette période.…”