BX. BY. Thelepus plagiostoma ?Thelepus extensus. Terebellides stroemi lasmineira caeca. Perkinsiana antarctica. Demonax krusensterni. Serpula vermicularis ...
BULLETIN OF MARINE SCIENCE, 48(2): 358-368, 1991
BIOGEOGRAPHY AND POLYCHAETE ASSEMBLAGES FROM SUBANTARCTIC ISLANDS (INDIAN OCEAN): MARION DUFRESNE MD/08 BENTHOS EXPEDITION TO MARION, PRINCE EDWARD AND CROZET ISLANDS Patrick Gillet ABSTRACT During the MD/08 Benthos Expedition (from 7 March to 26 April 1976) about 7,000 polychaetous annelids were collected from 70 stations from Marion, Prince Edward Islands and Crozet Islands. A cluster analysis was used to define benthic polychaete taxocoenoses with a matrix data of 77 species and 55 samples. Six polychaete assemblages were found in which two were original: an assemblage occurring in shallow water and black sand with Pseudonereis anomala. Leitoscoloplos fragilis and Travisia kerguelensis and a second group in deeper water and hard bottom with Polyeunoa laevis the dominant species. These polychaete assemblages occurred on the continental shelves of Marion, Prince Edward and Crozet Islands, and were discussed in relation to their biogeography and compared with the fauna of South Africa and the Kerguelen Islands.
Since the Challenger Expedition in 1873, different authors have studied po1ychaetes from the Kerguelen region (Fauvel, 1952; 1953a; 1953b; RuHier, 1966; 1973; BeHan, 1975). Day (1971) described a small collection ofpolychaetes from the intertidal zone of Marion and Prince Edward Islands. Earlier, polychaete assemblages from the Kerguelen Islands were studied by Chardy et at. (1976), Desbruyeres (1977), and Desbruyeres and Guille (1977). The MD/08 Benthos Expedition was described by Arnaud and Hureau (1979) and the taxonomy of polychaetes collected from Marion and Prince Edward Islands has been studied by Gillet (in press). Axiothella crozetensis. a new maldanid, was described by Gillet (1989). Myriowenia sp. (Family Oweniidae) was not identified to species and this genus is reported for the first time from the southern hemisphere. MATERIALS AND METHODS A general description of the Marion Dufresne, MD/08 Benthos Expedition, was given by Arnaud and Hureau (1979). The species examined in this work were collected from 70 stations from Marion, Prince Edward and Crozet Islands (Fig. lA, B, C). Sites were sampled from 21 March to 21 April 1976 from depths between 25 to 1500 m. Most of the stations were from depths between 100 to 500 m (46 stations); five stations between 500 to 1,000 m and four stations were taken from depths greater than 1,000 m. The depths of the other stations are unknown. Different sampling methods were used: Charcot dredge (DC), Okean grab (BB), Lithods nets (CL) and a trawl (CP). A description of the stations is given in Table I. For 18 stations, the volume sampled was 75 to 100% of the total volume. Twenty-six stations had a volume between 50 to 75%, seven stations a volume between 25 to 50% and nine stations a volume less than 25% of the total volume. For six stations, the volume sampled was 0%. The volumes of four other stations are unknown. The most common substratum was sand and mud-sand (24 stations). Rocks were present at six stations; sand and black sand at 16 stations; clay-sand or mud-sand at eight stations and mud at eight stations.
358
GILLET: SUBANTARCflC
ISLAND POLYCHAETE
.. . ... ..... .··. . .. .. .. .. .. ............ ·. . .. . . . .. .... ..:.:.:.:.:.:.:.:.:.:.:.
359
ASSEMBLAGES
A ..•.........•.•.....•.• .
Indian
Ocean
REUNION
2O'S
3O'S
4O'S
8.
I
PRINCE EDWARD MARI0I-N--========~
-•..•CROZET
[!]
10 to 37
39 to 19 50'S
40'E
SO'E
eO'E
70'E
Figure IA. Station locations of the Marion Dufresne, MD/08 Benthos Expedition, 7 March to 26 April 1976 (from Arnaud and Hureau, 1979). The hierarchical classification was used for 77 species and 55 samples with the x2 distance (Benzecri et aI., 1980) on a Prime Microcomputer PST 100. n;
d2(j, j') = ~
"»)2
(kC ') k(i klG~ - kG!)
with k(i) = ~ k(ij) k(j)
= ~
k(ij)
ni
k= ~
k .k(i)
j = 1 to nj i
=
1 to ni
nj
k(i) = ~ k(j) j-I
j"'-I
RESULTS
About 7,000 polychaetes were collected: 3,779 from Marion and Prince Edward Islands and 3,149 from Crozet Islands. Abundance varied from 0 to 655 specimens (sta. 22) from Marion and Prince Edward Islands and from 0 to 347 polychaetes
BULLETIN OF MARINE SCIENCE, VOL. 48, NO, 2, 1991
360
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Figure 1. B. Marion and Prince Edward Islands station locations. C. Crozet Islands station locations.
GILLET: SUBANTARCfIC
ISLAND POLYCHAETE
ASSEMBLAGES
Table 1. Location of the stations, depth, sampling methods and efficiency of sampling methods Stations nnd samples
Lat. S
Long. E
Depth (m)
09 CL 61, CP 64,65,66 DC 68, CP 74, 75 BB 69 10 CL 76 II CL 77 12 BB 79 13 CP 85 14 DC 86; DC 155 15 BB 88 16 CL 95 17 BB 97 18 DC 107; BB 108; RK 109 19 DC 110; BB 111 20 CP 116 21 BB 119 22 DC 124; BB 125 23 DC 129 24 CC 128 25 CP 134 26 CP 135 27 DC 136 28 DC 143; DC 148 2930 DC 153 31 DC 156; BB 157 32 DC 162 33 DC 164 34 DC 167; BB 168 35 DC 170 36 CP 173 37CP174 39 BB 183 40 DC 186, BB 192 41 DC 193 42 CP 197 43 DC 198 44 CP 199 45 CP 203 46 CP 204 47 DC 205 48 CP 209 4950 DC 216, RK 217, BB 218 51 DC 221, BB 223 52 DC 224, BB 225 53 DC 233 54 CP 234, BB 236 55 CP 237 56 BB 240 57 DC 241 58 CP 244 59 DC 252, BB 253 60 DC 248, BB 250 61 DC 255 62 CP 257 63 BB 259 64 DC 260, BB 264 65 CP 269 66 DC 270 67 D 271, BB 273
46.225 S 46.528 S 46.522 S 46.557 S 46.563 S 47.012S 46.577 S 46.502 S 46.521 S 46.498 S 46.462 S 46.472 S 46.533 S 46.524 S 46.579 S 46.528 S 46.453 S 46.506 S 46.457 S 46.435 S 46.510 S 46.478 S 46.595 S 46.590 S 46.522 S 46.502 S 46.397 S 46.407 S 46.424 S 46.187S 46.211 S 46.228 S 46.214 S 46.1858 46.180 S 46.122 S 46.106 S 46.106 S 46.050 S 46.060 S 45.515 S 46.050 S 46.071 S 46.075 S 45.568 S 45.571 S 45.465 S 45.462 S 45.473 S 45.598 S 46.034 S 46.057 S 46.057 S 46.0478 46.020 S 46.019 S 46.153 S 46.170 S
51.513 E 37.525 £ 37.539 E 37.541 £ 37.556 E 37.474 E 37.599 E 37.591 £ 37.538 E 37.562 E 38.032 E 38.035 E 37.530 £ 37.519 E 38.013 E 37.525 E 37.566 E 38.006 E 37.540 E 37.572 E 37.580 £ 38.004 E 37.468 E 37.468 E 37.515 E 37.512E 38.003 E 38.067 E 38.124 E 51.295 E 51.327 £ 51.330 £ 51.349 E 51.110£ 51.140 E 50.470 £ 50.147 £ 50.458 E 50.371 E 50.345 E 50.365 E 50.184 E 50.198 E 50.206 £ 50.207 E 50.216 E 50.207 £ 50.053 E 50.018 £ 49.583 £ 49.476 £ 50.089 E 50.019 £ 49.190£ 49.085 £ 49.085 E 49.133£ 49.370 £
50 to 150 45115 to 120 95 to 103 120260 to 710 185 to 210 138 to 142 110 to 112 138 to 140 185 to 190 18050 to 57 30 to 31 250 to 460 52185 to 232 135 to 145 180 to 190 246 to 285 14058185 to 197 83 to 100 4595 to 115 53315t0570 690 to 1050 330 to 375 171 to 190 12017214001500535375490200190143 to 150 2553 to 62 110110 to 143 150165 to 170 205210210 to 215 245t0271 67210480 to 525 930 to 980 1000500275 to 280-
Substratum and efficiency of sampling method (%)
Sand 25-50% 50-75% Clay sand (25-50%) 50-75% 0%Sand (0-25%) 25-50% Clay sand (50-75%) Clay sand (25-100%) Mud (0-75%) 50-75% Black sand (25-50%) Sand (25-75%) Rocks sand (25-50%) 50-75% 50-75% 75-100% 50-75% Sand (50-75%) ? Rocks, Macrocystis «25%) Black sand (0-50%) Sand Rocks (50-75%) 50-75% Mud (25-75%) Rocks (50-75%) Rocks (75-100%) 0%Black Mud (0-25%) Mud sand (50-75%) 0%75-100% Mud sand (75-100%) Mud (50-75%) 0%50-75% 0%75-100% Black sand (0-25%) Black sand (75-100%) Black sand (75-100%) 0-25% Black sand (75-100%) 50-75% 0-25% Mud sand (75-100%) 0%Mud sand (50-75%) Mud (75-100%) Sand (0-25%) 50-75% Sand (0-25%) Mud (50-75%) 25-50% Rocks (0-25%) Mud (50-75%)
361
362
BULLETIN OF MARINE SCIENCE, VOL. 48, NO.2,
Table I.
1991
Continued
Stations and samples
68 CP 275 6970 DC 280, 71 DC 283, 72 DC 289, 73 CP 295 74 DC 296, 75 CP 303, 76 CP 305 77 DC 314, 78 CP 319 79 DC 322,
BB 281, RK 282 BB 285, BB 286 BB 291 BB 297 304, 306 BB 315 BB 232
Long. E
La!. S
46.166 46.464 46.450 46.375 46.245 46.242 46.183 46.210 46.258 46.245 46.237 46.246
S S S S S S S S S S S S
49.370 50.332 50.290 50.390 50.330 50.347 50.480 51.520 52.037 51.598 51.581 51.538
E E E E E E E E E E E E
Depth (m)
27013001022 to 268 to 187 to 190 to 210 to 100 to 50 to 250 to 14295 to
1350 270 196 263 290 155 52 270 105
Substratum and efficiency of sampling method (%)
50-75% 50-75% Mud (75-100%) 75-100% Sand (75-100%) 75-100% Mud sand (75-100%) 75-100% Sand Sand (50-75%) 75-100% Sand (50-75%)
(sta. 9) from Crozet Islands (Fig. 2A, B). The average number of species from Marion and Prince Edward Islands was about 10 species with the range from one species present to station 18 with 26 species. From Crozet Islands, the number of species by station ,-washigher with an average of 13 species and the range from 6 to 36 species present (Fig. 3A, B). The most abundant species was Eunice pennata (Muller, 1776) with 1,365 specimens, 19.7%, followed by Harmothoe magellanica (McIntosh, 1885) with 446 specimens, 6.4%, Anobothrus patagonicus (Kinberg, 1867) with 361 specimens, 5.2%, Notomastus latericeus Sars, 1851 with 331 specimens, 4.8%, Kinbergonuphis tenuisetis (McIntosh, 1885) with 321 specimens, 4.6%, Exogone heterosetosa McIntosh, 1885 with 304 specimens, 4.4%, Pionosyllis elhersiaformis (Augener, 1913) with 258 specimens, 3.7%, Laetmonice producta Grube, 1877 with 200 specimens, 2.9% and Eusyllis kerguelensis McIntosh, 1885 with 171 specimens, 2.5%, and Paraonis uncinatus (Hartman, 1965) with 137 specimens, 4.4%, Trypanosyllis gigantea (McIntosh, 1885) with 123 specimens, 3.9%, was collected only from the Crozet Islands. The distribution of the most abundant species around Marion and Prince Edward Islands shows that Exogone heterosetosa and Anobothrus patagonicus live near the coast at about 100 m depth. Eunice pennata and Laetmonice producta live in deeper water. Around the Crozet Islands, Harmothoe magellanica and Eunice pennata were collected from Possession Island and East Island, but Paraonis uncinatus from the west of Apostoles Island and Pigs Island. Kinbergonuphis tenuisetis was collected between Penguins Island and Apostoles Island. Eunice pennata was found on all types of substratum, at all depths. Lumbrineris gracilis (Ehlers, 1868) was previously known only from Madagascar (Amoureux, 1974), and Kinbergonuphis tenuisetis only from New Zealand (Fauchald, 1982). Three species, Euphrosine cirrata (Sars, 1862), Hemipodus simplex (Grube, 1857) and Micromaldane ornithochaeta (Mesnil, 1897) had only been collected previously from the Antarctic. Cluster analysis (Fig. 4) was based on 55 samples and 77 taxa identified to species which had more than one specimen present. Two major clusters were present, each with several polychaete assemblages, one in depths less than 200 m and the second in depths greater than 200 m. The shallow water cluster « 200 m) contain the following assemblages: Assemblage (1) with two species on hard bottom with Amphitrite kerguelensis (BN) and Thelepus plagiostoma (BS). Assemblage (21) in black sand with Pseudonereis anomala (S), Leitoscoloplosfragilis (AG) and Travisia kerguelensis (BA). Assemblage (22) with Anobothrus patagonicus (BK), Notomastus latericeus (BC), Prionospio ehlersiaformis (0), Exogone
GILLET: SUBANTARCTIC
ISLAND POLYCHAETE
363
ASSEMBLAGES
A. EDWARD
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71
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50"E
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, 51'e
,
30"
5~"e
\
Figure 2. A. Abundance ofpolychaetes collected around Marion and Prince Edward Islands. Abundance: a Polychaete,. 1-50,.50-100,. 100-250, • 250-500 and. >500. B. Abundance of polychaetes (symbols as in 2A) collected around Crozet Islands.
*
364
BULLETIN OF MARINE SCIENCE, VOL. 48, NO.2,
1991
A. EDWARD
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