Jc. Dauvin et S. Zouhiri, SUPRABENTHIC CRUSTACEAN FAUNA OF A DENSE AMPELISCA COMMUNITY FROM THEENGLISH-CHANNEL, Journal of the Marine Biological Association of the United Kingdom, 76(4), 1996, pp. 909-929
Ninety-six species (97,677 individuals) were collected over the course
of 6 h in five suprabenthic sledge hauls from a very dense Ampelisca
fine sand community from the Bay of Morlaix (western English Channel).
All the species migrated into the water column at night (98% of the s
pecimens collected in the suprabenthos were found in the night hauls).
The 23 most abundant species collected were classified into five grou
ps based on their height within the water column, but two groups predo
minated: the upper suprabenthic species, abundant at 0.80-1.45 m above
the sea-bed; and the lower suprabenthic species which were abundant o
nly near the sea bottom (similar to 0.1-0.75 m high). Three different
patterns of nocturnal vertical migration were distinguished based on t
he timing of maximum swimming activity: at dusk; at the beginning of t
he night; or later in the night. Sexually dimorphic patterns of free-s
wimming behaviour was observed in Ampelisca and some other species of
Amphipoda (Bathyporeia tenuipes, Metaphoxus fultoni), and Cumacea (Bod
otria pulchella, Pseudocuma longicornis), with many more males than fe
males migrating into the water column at night. Finally, the density o
f suprabenthic crustaceans in nocturnal hauls was amongst the highest
reported from infralittoral or circalittoral suprabenthic studies on o
ther parts of the Atlantic Ocean sampled during spring.