Oceanic Dispersal and Seamount Colonization by the Neritic Mysid Anchialina Agilis (G.O. Sars, 1877) in the North-eastern Atlantic

The neritic mysid Anchialina agilis (G.O. Sars, 1877) had been recorded off the Portugal coast and on the Lusitanian and Azores Atlantic seamounts. This mysid shows daytime migration; it was near the sea-bottom during the day and migrated towards the surface waters during the night. Current advection from the coast to offshore is probably the origin of the large dispersal of the species from the Iberian and north-African coast to the seamounts. On seamounts at water depths compatible with the existence of a benthic population, permanent populations composed of juveniles, immature specimens, and incubatory females and matures males were established in a seamount retention system. The existence of a regular flux of coastal individuals from the north-eastern Atlantic continental shelf and the reproduction within seamount-established populations appears sufficient to maintain offshore populations of this species