Ancient sea creatures at risk in Spirits Bay

Forest and Bird, Issue 294, 1 November 1999, Page 4

Ancient sea creatures at risk in Spirits Bay

, Origin

Natural History Media.

—Dave Hansford,

na May afternoon in 1996, a fishing vessel took a slow, deliberate course across the broad sweep of Spirits Bay at the northernmost tip of New Zealand. Behind it, some 30 metres below, a scallop dredge bucked and shovelled along the sea floor, steel tines grubbing sand dwellers from the soft sediment. Marine biologists were aboard the vessel, conducting a scallop assessment for the Ministry of Fisheries to help set the scallop quota for the coming season. A series of tows across neighbouring Tom Bowling Bay had yielded encouraging numbers of scallops, but little else of scientific interest. Here in Spirits Bay the story was quite different. Amidst the scallops in the sorting tray, clapping their valves in protest, was a sponge like none seen before. Eight tows and many more specimens later, they knew they were steaming over a very special piece of seabed. Back in the Wellington laboratories of NIWA, the National Institute of Water and Atmospheric Research, the Spirits Bay specimens were scrutinized. Aside from the strange sponges, there were bryozoans, two puzzling kinds of octopus, an unrecognized species of crab, a tiny barnacle, a starfish and a hydroid. The identification of some of these creatures resisted the combined knowledge of experts both here and overseas: they were simply unknown to science. More than a third of the sponges were peculiar to one small area of Spirits Bay. The octopus was a first for New Zealand. One of the hydroids, itself very rare, was the exclusive host to a new barnacle the nearest known relative of which had gone extinct nearly 300 million years ago. Of those animals known, some were unusually isolated — hydroids otherwise found only in New Caledonia, sponges and

octopus from Australia’s Great Barrier Reef. The most bizarre occurrence was the bryozoan that lives in just two places on earth — Spirits Bay, New Zealand, and Tierra del Fuego, South America. NIWA researchers produced a report for the Ministry of Fisheries outlining the biological wealth of the area and the consequences of continued commercial scallop dredging. Protection was recommended until the coastal communities could be surveyed. The advice was not taken, however, and dredging continued. In fact, despite ever more insistent recommendations by NIWA scientists following their pre-season assessments in 1997 and 1998, both scallop dredging and trawling continue today in Spirits Bay. Scientists and environmentalists now fear the worst for the 27 species that are either peculiar to Spirits Bay, or of very restricted range or rarity. It is not all bad news. In response to NIWA’s 1997 report to the Ministry of Fisheries (Mfish), the scallop fishermen agreed to voluntarily close an area of some 100 square kilometres off Spirits Bay and neighbouring Tom Bowling Bay ‘pending further research. The Mfish policy manager, Graeme McGregor, says the scallop fishermen agreed to the nonpoliced closure because many of the animals typical of the Spirits Bay seabed, particularly hydroids, are thought to play a critical nursery role in the life cycle of the scallop spat. Mfish celebrated the voluntary closure as a step toward achieving a balance between protecting the environment and allowing sustainable scallop fishing, but environmentalists did not agree. Cath Wallace, co-convenor of the environmental umbrella group ECO, says the closed zone protects only 13 percent of the invertebrate communities so far dis-

covered. The vast bulk of the bryozoans, the meadows of hydroids and their barnacles, and a good proportion of the sponges are outside the area, at the mercy of the scallopers’ dredges. Most of the closed area encroaches only slightly onto the scallop beds. As well, trawlers continue to tow nets through the zone. Bruce Young, spokesman for Pagrus Auratus, an organization representing snapper-quota holders in the Northern Area Fishery, says trawlermen do not recognize the closed zone and do not accept they are damaging the animals. Professor John Buckeridge, Auckland Institute of Technology, who is describing the new barnacle, says preserving the new species matters. ‘People don’t seem to understand that the whole biosphere is interrelated. Recent research hints that marine species hold great medical potential. With every extinction another option for the future is lost. NIWA scientists are worried that protection may now be too late. Last season’s scallop num-

bers were so low that NIWA recommended a reduction in the annual take from 188 to 106 tonnes; dead hydroids, and scallops with shell damage, were also hauled up out of the closed area. The damage was consistent with having been struck by a scallop dredge or the weights of a trawl net.