(amphipods: 48.2%; mysids: 14.9%; cumaceans: 13.5%; isopods: 11.1%).
Some of these species were anterioriy considered as endemic of the Mediterranean Sea (the mysid Hrythrops neapolitana; the amphipods Carangoliopsis spinulosa, CepechineUa manco, Arrhis mediterraneus, Pardalisca
mediterranea, Andaniexis mimonectes, Parvipalpus major) and their presence in the bathyal of the SE of the bay of Biscay is probably related
to the flow of Mediterranean water below 500 m water depth in that
area, as suggested by Pejpouquet (1973) for benthic ostracods. The
newly described amphipod Bathymedon longirostris from the Catalan slope
0aume et al, 1998) was surprisingly abundant on the northern flank of
the canyon (station C
7 ). Finally, a lot of species were probably new to
science and will be described elsewhere: the amphipods Eusirus sp., Listriella sp., Hippomedon sp., Melphidippa sp., Oediceroides sp.; the isopods
Haplomesus sp., Upomera sp.
Structural characteristics of the suprabenthic assemblages
from the Capbreton area. St : species richness (number of species/sample);
Dt: total density (ind./100 m
2 ); H': Shannon index (log2); J: evenness.
Shelf
Canyon
Slope
Stations
D
C’
H
17
B
A
Depth (m)
162
308
766
812
555
987
Ncts
Fl-4
14-4
Fl-4
F1 4
14-4
Fl-4
Arcn (m
2 )
238.3
186.4
267.5
377.9
392.0
259.9
St
36
85
66
43
94
45
Pycnogonida
n
o
o
o
1
0
Mysidacca
9
13
9
8
9
7
Amphipoda
17
40
32
24
43
22
Cmmacea
2
12
1 1
3
12
10
Isopoda
2
8
8
4
16
3
Tanaidacea
0
3
2
1
3
0
Euphausiacea
1)
1
1
1
2
1
Dccapoda
5
7
3
2
6
2
Pisces
1
1
0
0
2
0
Dt
1621.6 3918.1
61 7 .2
56.6
301.3
62.7
% Pycnogonida
n.n
0.0
0.0
0.0
0.3
0.0
% Mysidacea
30.3
5.2
6.1
15.0
7.2
2 7 .6
% Amphipoda
61.(1
60.8
47.8
69.6
44.5
49.7
% Cumacea
0.4
15.9
12.2
6.5
15.4
19.0
% Isopoda
0.1
1 (,.9
31.0
(,.6
29.6
1.9
% Tanaidacea
0.0
0.8
1.8
0.5
0.7
0.0
% Kuphausiacca
0.0
0.0
0.1
0.9
0.3
0.6
% Decapoda
8.2
0.4
1.0
0.9
1.7
1.2
% Pisces
0.0
0.0
0.0
0.0
0.3
0.0
H’
2. 7 1
4.18
4.46
4.54
5.18
4.91
J
0.52
0.65
0. 7 3
0.84
0.79
0.89
90