1980/1981. R W Grigg

Transcription

1 TECHNICAL REPORT NO May 1981 SPECIES IDENTIFICATION AND ASSESSMENT OF CCOP/SOPAC PRECIOUS CORAL COLLECTIONS 1980/1981 by R W Grigg Prepared for: As a contribution by: COMMITTEE FOR CO-ORDINATION OF JOINT PROSPECTING FOR MINERAL RESOURCES IN SOUTH PACIFIC OFFSHORE AREAS (CCOP/SOPAC) UNDP Project Office Project RAS/79/074 Investigation of Mineral Potential of the South Pacific

2 SPECIES IDENTIFICATION AND ASSESSMENT OF CCOP/SOPAC PRECIOUS CORAL COLLECTIONS by Richard W. Grigg Hawaii Institute of Marine Biology P. 0. Box 1346 Kaneohe, Hawaii May 11, 1981

3 SUMMARY The collections from Kadavu, Tanna Island, Vanuatu and the Solomon (Santa Cruz) Islands contain numerous deep water black corals (4 species), deep water gorgonians (10 species not counting the pink corals), Corallium - the genus of commercial pink and red coral (7 species), deep water scleractinians (3 Oculinids, 5 Dendrophyllids and 4 Caryophyllids), deep water hydrocorals (5 species), deep water Alcyonarians (4 species) and two deep water brozoans. Two shallow water coral fragments were also present obviously having been transported down-slope. In general, the specimens representing many deep water species are very small bordering on the miniture in some cases. This suggests the areas sampled are not characterized by strong bottom currents. Efforts should be made to direct future sampling in areas where strong currents can be expected such as within channels between islands. The species present in the collections belong to the community in which the commercial pink and red corals are found, so it is likely that the proper depth ranges were sampled. Some station collections contained numerous dead fragments and talus material indicating steep island slope habitats, which are not the most suitable for commercial grade precious coral. In such habitats the continuous transport of sediment downslope leads to high mortality and generally hinders the growth of large colonies. Exceptions occur in areas where very strong currents are present. The best habitats are rises, banks or ridges surrounded on all sides by deeper water and situated where current flow on the bottom is strong. In this area of the Pacific, the best depths are meters.

4 2 Unfortunately such habitats may not be common in many areas of the South Pacific because of the geologic history of the basin. In most areas within 300 meters of the surface, sea level and tectonic motion have varied such that reef building corals have been able to reach the present day surface essentially eliminating a deep water habitat between meters and replacing it with steep sided island flanks. Much more research is required before this hypothesis can be adequately tested. In conclusion, the samples contained in these collections are not promising in terms of locating commercial grade beds of precious coral or finding suitable habitats where precious corals are known to occur. Future exploratory efforts should be directed at locating areas where suitable habitat is abundant. Earlier collections in the South Pacific made under the auspices of CCOP/SOPAC suggest that areas at more southerly latitudes and near the western rim of the Pacific are the most promising.

5 3 NOTES ON CCOP/SOPAC COLLECTIONS I. KADAVUL SAMPLES FJ-80-1, Stn. 3, Sample TN-4. Depth: F Station Description: North side of Kaadvu on steep slope off fringing reef 1. large white coral - Neohelia sp., Family Oculinidae, Order Scleractinia 2. branched brown coral - Suborder Caryophylliina, Order Scleractinia 3. red sea fan - Paracis sp., Order Gorgonacea 4. purple soft coral - Family Nephtheidae, Order Alcyonacea 5. light yellow branching coral - Family Briareidae, Order Gorgonacea 6. black coral - Cirrhipathes sp. None of these samples are of commercial value; this group is representative of a community generally shallower than pink or gold coral and deeper than the commercial black corals. FJ-80-1, Stn. 4, Sample TN-7. Depth: F Station Description: North side of Kadavu on steep slope off fringing reef Sample: Oculina sp., Family Oculinidae, Order Scleractinia FJ-80-1, Stn. 6, Sample TN-10. Depth: Station Description: North side of Kadavu steep to moderate slope off fringing reef Sample: Corallium sp. white with pitted corallum, no commercial value, Family Corallidae, Order Gorgonacea. No commercial importance, skeleton too small and too white.

6 4 General: None of the FJ-80-1 samples are very promising, however, all were taken on a moderately steep slope at F off the fringing reef. Normally this is not the best habitat. The depth is right but the bottom configuration is probably not. A rise or bank between islands in mid- channel regions is best. 11. TANNA ISLAND SAMPLES VA-80-2, Stn. 6, Sample TN-1. Depth: F Station Description: Tanna Island Samples: 1. white stoney coral, Acrhelia sp., Family Oculinidae, Order Scleractinia 2. black coral bottlebrush, Antipathes sp., Order Antipatharia 3. gold coral (zig-zag skeleton), Family Chrysogorgiidae, Order Gorgonacea 4. soft coral, Family Briareidae, Order Gorgonacea VA-80-2, Stn. 6, Sample TN-3. Depth: M Station Description: Tanna Island 1. red coral, Corallium sp. c.f. japonicum, outstanding color, would be of high grade commercial value if larger (fragments only 3 cm long) 2. orange coral, Narella sp., Family Primnoidae, Order Gorgonacea 3. Dendrophyllia sp., Family Dendrophylliidae, Order Scleractinia

7 5 VA-80-2, Stn. 7A, Sample TN-7. Depth: M Station Description: Tanna Island 1. white stoney coral, Neohelia sp., Family Oculinidae, Order Scleractinia 2. white cup coral, Order Caryophyliina 3. white precious coral, small fragments of Corallium spp., Family Corallidae, Order Gorgonacea 4. soft coral, Family Briareidae, Order Gorgonacea VA-80-2, Stn. 7A, Sample TN-8. Depth: M Station Description: Tanna Island 1. two species of pink coral, Corallium tortuosum and Corallium sp., both are too small to be of commercial value. Family Corallidae, Order Gorgonacea. 2. Dendrophyllia sp., Family Dendrophylliidae, Order Scleractinia 3. Paracis sp., Family Eumuricea, Order Gorgonacea 4. bottlebrush gorgonian, Thouarella sp., Family Primnoidae, Order Gorgonacea 5. white finely branched sea fan, Callogorgea sp., Family Primnoidae, Order Gorgonacea. General: The Tanna Island collections contain four species of Corallium, the genus containing the precious pink corals. Unfortunately all are too small to be of commercial value. The stations covered in the survey spanned the proper depth zone, therefore these samples are probably repre- sentative of what is there. Apparently the large commercial grade species are not present in this area of the Pacific.

8 6 III. VANUATU SAMPLES VA-80-3, TN-17 Station Description: West of Epi 1. fragments of bryozoa 2. fragment of dead Millaporinid coral from shallow water; evidence of talus and downslope sediment transport 3. small black coral Antipathes sp., Order Antipatharia. VA-80-3, TN-18 Station Description: West of Epi 1. hydrocoral, Order Stylasterina 2. dead Caryophyllid cup coral, Order Scleractinia VA-80-3, TN-19 and VA-80-3, TN-20 Station Description: West of Epi Sample: Unrecognizable dead fragments of gorgonian skeleton, bryozoa, and a dendrophillid coral VA-80-3, TN-22 Station Description: West of Epi Sample: Dead fragments of Dendrophyllid and Oculinid corals. VA-80-3, TN-03 Station Description: West of Epi 1. fragments of the pink hydrocoral Stylaster sp., Order Stylasterina, Class Hydrozoa

9 7 2. fragment of Neohelia sp., Family Oculinidae, Order Scleractinia 3. fragment of Dendrophyllid coral VA-80-3, TN-24 Station Description: West of Epi 1. fragment of Caryophyllinid coral Paracyathus sp., Family Caryophylliidae, Order Scleractinia 2. fragment of Dendrophyllid coral VA-80-3, TN-27 Station Description: East of Santo Sample: fragments of dead Dendrophyllid corals VA-80-3, TN-29 Station Description: East of Santo 1. cup coral, Family Caryophylliidae, Order Scleractinia 2. Neohelia sp., Family Oculinidae, Order Scleractinia VA-80-3, TN-30 Station Description: East of Santo 1. Paleopsammia sp., Family Dendrophylliidae, Order Scleractinia 2. hydrocoral fragment (chalky white) 3. bryozoa fragment

10 8 VA-80-3, TN-39 Station Description: West of Gaua 1. favinid cup coral 2. tiny fragment of Corallium sp. covered with manganese (black) coating 3. red bryozoa fragment 4. Neohelia sp., Family Oculinidae, Order Scleractinia 5. hydrocoral fragment 6. black coral, Antipathes subpinnata VA-80-3, TN-43 Station Description: West of Gaua Sample: fragments of dead Dendrophyllid and Oculinid corals VA-80-3, TN-44 Station Description: West of Gaua 1. tiny fragments of Corallium sp. 2. Neohelia sp., Family Oculinidae, Order Scleractinia VA-80-3, TN-47 Station Description: Northwest of Mota Lava 1. fragment of red sea fan, Paracis sp., Family Eumuricea, Order Gorgonacea 2. fragment of hydrocoral

11 9 VA-80-3, TN-57 Station Description: East of Toga (Torres Islands) Sample: fragments of Dendrophyllid corals VA-80-3, TN-58 Station Description: East of Toga (Torres Islands) 1. Acrhelia sp., Family Oculinidae, Order Scleractinia 2. fragment of hydrocoral 3. Dandrophyllid cup coral VA-80-3, TN-59 Station Description: East of Toga (Torres Islands) Samples: 1. Neohelia sp., Family Oculinidae, Order Scleractinia 2. fragment of hydrocoral VA-80-3, TN-60 Station Description: East of Toga (Torres Islands) Samples: 1. gorgonian fragment, Paracis sp., Order Gorgonacea 2. jointed gorgonian, Parisis sp., Family Parisididae, Order Gorgonacea 3. Dendrophyllid fragments 4. Enallopsammia sp., Family Dendrophylliidae, Order Scleractinia VA-80-3, TN-61 Station Description: East of Toga (Torres Islands)

12 10 1. gorgonian fragment Paracis sp., Order Gorgonacea 2. Dendrophyllid fragments 3. hydrocoral fragments 4. bryozoa fragment 5. precious pink corals Corallium spp., Family Corallidae, Order Gorgonacea. Too small for commercial value, however, the color of the red variety (c.f. japonicum is of the highest quality) VA-80-3, TN-63 Station Description: East of Toga (Torres Islands) 1. fragments of Corallium sp., Family Corallidae, Order Gorgonacea. Too small to have commercial value. 2. fragments of bryozoa 3. fragments of Dendrophyllid corals VA-80-3, TN-64 Station Description: East of Toga (Torres Islands) Sample: fragments of Dendrophyllis corals General: The samples from Vanuatu are not promising. All 20 contain small and poorly developed corals representing primarily the deep water families Oculinidae, Dendrophylliidae, Caryophyllidae and Corallidae. The Corallidae are the precious corals and three species are contained in the collection, however, all three are small and inconspicuous. No fragments of larger colonies were contained in the collection. In view of the large number of stations occupied (20) it is probably correct to conclude that no

13 11 large precious corals occur in this area. However, it may be that the proper habitats were not sampled. No depth or position data were provided with the samples. Most were probably collected on steep sided island slopes between 150 and 300F; the proper depth but not the best habitat. Many fragments were dead suggesting the habitat sampled included talus zones instead of cleanly swept banks or ridges IV. SOLOMON ISLAND SAMPLES SI-81-1, TN-3 1. numerous moderately large fragments of hydrocoral (no commercial value) 2. red sea fan, Keroeides koreni, Family Keroeididae, Order Gorgonacea 3. orange sea fan, Swiftia sp., Family Paramuriceidae, Order Gorgonacea 4. pale pink sea fan, Ellisella sp (possibly laevis), Family Ellisellidae, Order Gorgonacea 5. black coral Antipathes subpinnata, Order Antipatharia (no commercial value). SI-81-1, TN-4 1. fragments of Dendrophyllid corals 2. fragments of black coral, Antipathes subpinnata, Order Antipatharia

14 12 SI-81-1, TN-5 Sample: fragments of dead Dendrophyllid corals SI-81-1, TN-6 Sample: two species of Corallium, Family Corallidae, Order Gorgonacea. Both small and poorly developed; of no commercial importance. SI-81-1, TN-10 Sample: dead fragments of Dendrophyllid coral SI-81-1, TN-12 Sample: fragments of dead Dendrophyllids, sponge fragment, bryozoa fragment, tiny fragment of black coral, Antipathes subpinnata SI-81-1, TN-13 Station Description: Soloman Islands (Santa Cruz) 1. bryozoa fragments 2. Corallium sp., Family Corallidae, Order Gorgonacea. The small size and form of this colony and others like it, suggest that Corallium spp. in the Santa Cruz Islands do not reach commercial size. SI-81-1, TN-15

15 13 Samples: 1. two species of very small bamboo corals or jointed gorgonians, Parisis sp., Family Parisididae, Order Gorgonacea and Lepidisis sp., Family Isididae, Order Gorgonacea 2. two miniature species of gold coral, Family Chrysogorgiidae, Order Gorgonacea one fragment of Callogorgia sp., Family Primnoidae, Order Gorgonacea two very small species of Corallium, Family Corallidae, Order Gorgonacea 4. bottlebrush black coral, Parantipathes sp., Order Antipatharia SI-81-1, TN Narella sp., Family Primnoidae, Order Gorgonacea 2. black coral (miniature tree), Antipathes (c.f., undulata), Order Antipatharia 3. black coral fragment, Antipathes subpinnata, Order Antipatharia 4. miniature Chrysogorgiid or gold coral 5. fragments of dead Dendrophyllids 6. small fragments of Corallium sp. SI-80-3, TN-19 Sample: dead fragment of hydrocoral SI-80-3, TN-20

16 14 1. Calyptrophora sp., Family Primnoidae, Order Gorgonacea 2. cup coral, Caryophyllid coral 3. bottlebrush black coral, Parantipathes sp., Order Antipatharia SI-81-1, TN-22 Station Description: Solomon Islands (Santa Cruz) 1. bottlebrush black coral, Antipathes sp., Order Antipatharia 2. hydroid 3. Dendrophyllid cup corals 4. shallow water coral, Turbinaria sp., Family Dendrophylliidae, Order Scleractinia. Presence of this species indicates this station is affected by transport of shallow water talus which in general is indicative of unfavorable conditions for precious corals SI-81-1, TN-23 Samples: 1. bamboo or jointed pale pink gorgonian, Parisis sp., Family Parisididae, Order Gorgonacea 2. red sea fan, Keroeides koreni, Family Keroeididae, Order Gorgonacea 3. white sea fan, Paracis sp., Order Gorgonacea 4. Oculinid fragment 5. hydrocoral fragments 6. two very small different species of Corallium. One is of excellent color but the growth form is far too small to be of commercial po- tential. The associated specimens of other species in samples from this area are very small bordering on "the miniature."

17 15 SI-81-1, TN-24 Station Description: Solomon Islands (Santa Cruz) 1. dead fragments of Dendrophyllid corals, sponges, and gorgonian skeletons 2. Corallium sp., Family Corallidae, Order Gorgonacea.. Excellent commercial grade color but specimens too small to be of significance SI-81-1, TN-31 Samples: 1. black coral bottlebrush, Parantipathes sp., Order Antipatharia 2. fragments of Dendrophyllid corals 3. fragment of dead bryozoan SI-81-1, TN-35 Samples: 1. Oculinid fragment, Acrhelia sp., Family Oculinidae, Order Scleractinia 2. fragment of scleraxonian gorgonian, Family Briareidae, Order Gorgonacea SI-81-1, TN Gorgonian branch, Narella sp., Family Primnoidae, Order Gorgonacea 2. black coral, Antipathes sp., Order Antipatharia

18 16 SI-81-1, TN-39 Sample: Gorgonian skeletal fragments, probably Family Suberogorgiidae (cannot classify without spicules) General: Four species of Corallium (pink coral) are contained in the Solomon Island collections, two of which are excellent commercial grade color. Unfortunately all are too small to be of commercial importance. Colonies must be 15 cm high and 1 cm in diameter to be of commercial value; the larger the more valuable. The small size seems to characterize other species in the Solomons assuming these stations (18) are representative. For example, the gorgonian corals, Narella, Calyptrophora and Callogorgia which are present in the collections are generally much larger in areas where commercial size Corallium is found. Samples of these corals in the Solomon collections range on the order of 1-10 cm, whereas these same genera in Hawaii in areas where commercial pink coral is found, frequently range between cm, i.e., about 1 order of magnitude Larger. This suggests that the areas samples are not areas characterized by strong currents. In Hawaii, the largest colonies of Corallium are found in areas where the strongest bottom currents occur. Also the presence of talus, broken pieces of shallow water coral (SI-81-1, TN-22 in particular) and many dead fragments of Dendrophyllid corals suggests that many of the stations were located on steep island slopes rather than rises, banks or ridges.