MEPS 218:179-187 (2001)  -  doi:10.3354/meps218179

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

Sergey V. Dobretsov1, Gilles Miron2,*

1Department of Invertebrate Zoology, St. Petersburg University, St. Petersburg 199034, Russia
2Département de biologie, Université de Moncton, Moncton, Nouveau-Brunswick E1A 3E9, Canada

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.

KEY WORDS: Habitat selection · Larvae · Mussel · Mytilus edulis · Settlement · Vertical distribution · White Sea

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