Larval and post-larval vertical distribution of the mussel Mytilus edulis in the White Sea

Abstract

The vertical distribution of veligers, pediveligers and post-larvae of the mussel Mytilus edulis L. was examined in Kandalakshsky Gulf (White Sea), Russia. Plankton samples showed that about 65% of all planktonic larvae were collected from a depth of 1.5 to 3 m. Maximum numbers of veligers were found at 3 m, immediately above the thermocline. The vertical distribution of veligers was stable throughout the study. The vertical distribution of pediveligers, however, varied over time. Pediveligers were mostly observed at 3 m before settlement peaked while they migrated closer to the water surface (1.5 m) during the settlement period. Pediveliger concentrations were correlated positively with small phytoplanktonic cell (<150 µm) and dissolved organic matter concentrations before settlement peaked. Both factors were correlated negatively with pediveliger concentrations during the settlement period. Newly settled post-larvae mainly colonized settlement panels situated at 1.5 m below the water surface (ca 70% of total post-larvae abundance). These results support the hypothesis that planktonic larvae of M. edulis change their vertical distribution in relation to larval stages, which in turn, increases settlement success.

Experimental trials on the feasibility of offshore seed production of the mussel Mytilus edulis in the German Bight: installation, technical requirements and environmental conditions

“…Data of larvae numbers determined in the water are equivalent to those reported by Dobretsov and Miron (2001) for the White Sea and Cáceres-Martínez and Figueras (1998) for NW Spain being t1.3 and 1.2 £ 10 3 m ¡3 , respectively. Due to a dilution eVect long drifts to oVshore sites result in declining densities of mussel larvae in the water column (Young et al 1998;Metaxas 2001;Buck 2004;Bos et al 2006).…”

Colonization of an artificial hard substrate byMytilus edulisin the German Bight

“…Only the upper areas (down to 3 m) of the submerged parts were fully covered by M. edulis while in deeper parts of the platform only single individuals and rare aggregates were observed. In the White Sea, Dobretsov & Miron (2001) also found highest settlement in about 1.5 m depth with densities of settled post-larvae decreasing below 3 m depth. This distributional pattern was, however, due to a strong thermocline/halocline retaining the larvae in upper water layers.…”

Spatio-temporal variability of larval abundance and settlement of Perna perna: differential delivery of mussels

“…Dispersal is highly complex and variable, as pelagic larvae exist in a highly patchy and extremely variable environment (McQuaid & Phillips 2000, Natunewicz & Epifanio 2001. While some bivalve larvae show active swimming behaviour, controlling their position in the water (Dobretsov & Miron 2001, Metaxas 2001 for review, Norkko et al 2001), studies on mussels indicate that larvae are transported passively, without even the vertical migration shown by barnacle larvae (Scheltema 1995, McQuaid & Phillips 2000, Satumanatpan & Keough 2001.…”

“…Larval patchiness and dispersal are, however, affected by a wide range of factors including seasonality of reproduction (Hurlbut 1991), hydrodynamics, water temperature, geography and topography , Pineda 1991, Bertness et al 1996, which have effects at different spatial scales (Dobretsov & Miron 2001, Poulin et al 2002. Temporal variation in larval availability and settlement is also important (Beukema et al 2001); apart from long-term (e.g.…”