Seamount Protection And Orange Roughy Reductions
Media Release – Wellington – 7 September 2000
SEAMOUNT PROTECTION AND ORANGE ROUGHY REDUCTIONS WELCOMED
The Forest and Bird Protection Society today welcomed the decision by Fisheries Minister, Pete Hodgson to protect 19 seamounts and to make major reductions in orange roughy catch limits.
Society spokesperson, Barry Weeber, said the protection of 19 underwater mountains was a major step forward in the conservation of New Zealand’s deepwater marine biodiversity.
“After four years of consultation a Minister of Fisheries has finally taken his responsibilities seriously and protected a range of underwater features. One of these features, the Bollons Seamount is over 100 nautical miles across.”
Mr Weeber said this action would help protect deep sea corals up to several metres high which are smashed by trawl nets. “These coral like orange roughy are long-lived. Gorgonian corals have been aged by NIWA at over 500 years and bamboo corals at over 300 years.”
“More action will inevitably be needed to protect further seamounts from fishing after further documentation of the environmental impacts of fishing is collected.”
Mr Weeber said the decisions to close the Challenger orange roughy fishery and to make major cuts to catch limits in the East Coast North Island orange roughy fisheries was warmly welcomed.
“These cuts are overdue and will hopefully allow the orange roughy populations to recover.” But that will take many, many years.
Mr Weeber said one disappointment in the Ministers decisions was his agreement to increase elephant fish and rig quota in the east coast of the South Island. “These two species are caught in part by gill nets which are known to catch Hector’s dolphin.”
information contact: Barry Weeber (04)385-7373 or
Background: The decline of Orange roughy fisheries
Orange roughy are considered to live to well over 100 years old and not start breeding till they are 23 to 29 years old. They are fished at depths of 700 to 1000m where they form dense spawning or feeding aggregations. These aggregations are often associated with seamounts, pinnacles or canyons. They are often caught in association with black and smooth oreos which are also long-lived.
The Sorry State of Orange Roughy Fisheries
Fishery % initial
population left* Current trend Current catch limit
(tonnes) Estimated Current Annual Yield (tonnes)
Challenger 3 Declining 1425 220
Northern unknown Declining 190 Unknown
Northern – Bay of Plenty 10-15 Declining 1000 16 to 30
East Cape 14 Declining 2000 130
East Coast North Island 10 Declining 1261 770
NW Chatham Rise 21-44 Declining 2250 930-2600
NE & E Chatham Rise 17-21 Unclear 4950 incl Sth Rise 3400-4400
South Chatham Rise Unknown Declining catch rates 4950 incl NE & E Chatham R Unknown
Puysegur 7 Unclear Closed 90-340
Southern Areas Unknown Declining? 5000 Unknown
WC South Island 22 Unknown 430 200
* Footnote: 30% is the agreed minimum population size for NZ fisheries.
Review of Orange
ORH 1: Principally Bay of Plenty – the main fishery started in 1995. A trawl survey in 1998 noted a 95 percent decline in spawning population size. The previous Minister of Fisheries, John Luxton, refused to take action to reduce the catch limit. The fishing industry did not honour an agreement to carry out another trawl survey in 1999 to check on the stock size. A survey was finally undertaken in June. This was used in the current assessment which estimates the stock is between 10 and 16 percent of its unfished size. This is under half the minimum target size of 30 percent. The current catch limit is over 30 times the estimated sustainable yield. Action: The catch must be cut to the sustainable yield this year
ORH 2A (North): East Cape North Island – the main fishery started in 1994 but the most recent assessment indicates that this stock is now half the minimum target size of 30%. While a cut in the catch limit occurred in 1998 the previous Minister of Fisheries, John Luxton, did not take a decision in 1999 to further cut the catch limit. The industry has in the past opposed a staggered reduction in catch limits to prevent over-fishing. Action: Further cuts in catches must happen this year.
ORH 2A (South), 2B, 3B: East Coast North Island – this fishery started in the early 1980s and has reduced the stock to 10 percent of its unfished size. Current catches are above estimates of sustainable yield. Action: Further cuts in catches must happen this year.
ORH3B (Chatham Rise): North-east and Eastern end:
This may once have been the world’s largest orange roughy
stock. The population has been reduced to around 17 percent
of its unfished size in just under 20 years. Current
catches are above some estimates of sustainable yield and it
is unclear whether the stock is rebuilding.
North-West: This population may or may not be above minimum sustainable limits. The assessment is highly uncertain and has not been updated for several years.
Puysegur: This fishery was closed in 1998 after the stock had crashed to 7 percent of its unfished state after 8 years. The fishing industry are talking about opening this fishery in the next year.
Auckland Islands and Antipodes: Recent evidence indicates these fisheries have been reduced to very low levels. Past catches were not sustainable but the former Minister of Fisheries refused to take action in the last 2 years to better control these small fisheries.
Other areas: State or size of other southern populations are unknown.
Action: Catch limits need reducing in southern areas.
ORH 7A (Challenger Plateau – West Coast South Island) – Fishing which started in the early 1980s has reduced this stock to 3 percent of its unfished state. Catch limits were reduced in 1998 when further concerns were raised as to whether the stock was rebuilding. Further reductions were supposed to happen in 1999 but the Minister of Fisheries, John Luxton, refused to put it on last year’s sustainability round. Action: this fishery should be closed.
ORH 7B (West Coast South Island) – Fishing which started in the mid-1980s has reduced this stock to around 22 percent of its unfished size. Current catches are still above most estimates of sustainable yield.
of the information on the state of orange roughy stocks is
based on Stock Assessments reviewed by the May 2000 Ministry
of Fisheries Stock Assessment Plenary and “Report of the
Fishery Assessment Plenary, April 1999: stock assessments
and yield estimates” compiled by Annala J H, Sullivan K J
and O’Brien C J, Science policy Ministry of Fisheries, May
Background information on Hector’s Dolphin
Hector’s dolphin is the world’s smallest and possibly the rarest marine dolphin with a population of 3-4,000. They occur only in New Zealand’s inshore waters and are rarely found more than 8 km from the coast.
Hector’s dolphin was gazetted late last year by the Minister of Conservation as a threatened species under section 2(3) of the Marine Mammals Protection Act 1978.
The dolphin is classified as a vulnerable threatened species in the most recent IUCN-World Conservation Union listings of globally threatened animal species (1996) . This listing is based on its small population size and the large number of dolphins drowned in set nets since at least 1980. Red lists or red data books of threatened species have been prepared for almost 30 years by IUCN. The Cetacean Specialist Group of the Species Survival Commission of IUCN, the world scientific experts on cetacean conservation, have assessed Hector’s dolphin as a threatened species of vulnerable status using the agreed threatened species criteria.
The dolphins mainly occur around the South Island but an additional population lives on the West Coast of the North Island between the Kaipara Heads and the Wanganui River. The main populations are found between Motunau and Timaru on the East Coast of the South Island, on the West Coast of the South Island, and in Foveaux Strait-Te Waewae Bay area in Southland.
Genetic work carried out by Auckland University indicates there are three relatively distinct populations of Hector’s dolphins (Pichler et al 1998) - East Coast South Island, West Coast South Island, and West Coast North Island. This means that each population must be managed separately when considering human impacts. The West Coast of the North Island population has been reduced to around 100 individuals between Taranaki Bight and the Manukau Harbour. Current research indicates that the west coast populations have been declining due to set nets deaths (Martien et al, 1999).
About 95 percent of the population is found around the South Island. Dolphins live to around 20 years old with females calving at 7-9 years old and males reaching sexual maturity from 6-9 years old. Females appear to calve only once every two to four years. Hector’s are probably the world’s smallest dolphin with a mature length of 119-145 cm and weighing up to 58kg.
Hector’s dolphins have been recorded drowned in both sets nets and trawl nets but the vast majority of the reports are from set nets. Around Banks Peninsula sets nets were estimated to drown over 230 dolphins between 1984 and 1987 (Dawson and Slooten, 1993).
Both commercial and recreational fishers have failed to report Hector’s dolphin deaths in set nets, a legal requirement of the Marine Mammal Protection Act. It wasn’t till a scientific observer programme was undertaken of set net and trawl vessels off the Canterbury coast that the true level of dolphin deaths was confirmed. As the previous Minister of Conservation, Nick Smith, said “What makes me particularly angry is that fishermen have for years failed to report fatalities and denied there was a problem”.
In the 1997-8 a Department of Conservation observer programme on commercial vessels recorded the deaths of six Hector’s dolphins. Observers covered only 89 of 351 fishing days. “I remain cynical that fishermen claim there were no deaths during the 262 days when observers were not present,” former Conservation Minister Nick Smith said. It is clear that neither commercial nor recreational set netters are reporting deaths of Hector’s dolphin.
Past Management Action:
In response to dolphin deaths in the 1980s the Banks Peninsula Marine Mammal Sanctuary was established late in 1988. It covers an area of 1140km2 around Banks Peninsula from Rakaia River to Sumner Head. The Sanctuary extends 4 nautical miles offshore and commercial set-netting is banned all year round and recreational fishing is prohibited between 1 November and the end of February.
This restrictions on set netting has almost eliminated set net deaths in the sanctuary but dolphins are still being killed north and south of the Sanctuary. Forest and Bird considers the sanctuary should be extended to include the area from Motunau to Timaru where a significant number of dolphins have been drowned in set nets.
Dolphins have been reported drowned with marks attributed to set nets around Taranaki and on the West Coast of the North Island. No management action has been taken to protect Hector’s dolphin in these areas.
More set nets?
The fishing industry is continuing to propose an increase in the catch limit for elephant fish (a shark) which is caught by set nets for the quota management area that includes the East Coast of the South Island. The Minister of Fisheries previously rejected a proposal to increase the catch by 50% because of concern over dolphin deaths.
The fishing industry is arguing that the use of pingers (noise generating devices) on nets can reduce dolphin deaths. To work pingers must not fail (they are battery powered), the right frequency must be used, the dolphins must not habituate to them and many pingers must be used per net. It is unclear whether they will work and it could take 6 years to confirm this during which up to 100 dolphins could drown.
This would require an dedicated observer programme. A recent International Whaling Commission (IWC) Sub-committee meeting on cetaceans raised concern at “pingers being deployed without any apparent attempt to either test their efficacy nor to monitor their effects”. They noted that “harbour porpoises and short-beaked common dolphins are the only cetacean species for which properly designed studies..have been conducted to evaluate pinger effectiveness. Nevertheless, some bycatch has occurred in nets with active pingers during experiments and seatrials”.
The IWC Committee was also concerned that dolphins could become habituated to the pingers so that, while there may be an initial drop in deaths, the rate may increase over time as dolphins get used to the pingers. This seems to have occurred with harbour porpoises where the main trial has taken place.
Previous work has indicated that the dolphin population at Banks Peninsula can only withstand around 1 individuals a year being killed by set nets from both recreational and commercial fishers (Dawson and Slooten, 1993). For the smaller West Coast North Island population no set nets deaths can be accepted.
management Action Needed:
Given these uncertainties and the risk to the dolphin, in particular the West Coast North Island population, Forest and Bird see only one option that is banning set nets where Hector’s dolphin live.
management action should be taken to reduce Hector’s dolphin
deaths from set nets by:
1. Establishing a marine mammal sanctuary on the West Coast of the North Island to protect the critically endangered and genetically isolated population found there. This should run from Wanganui to the Hokianga and extend 10 km offshore.
2. Expanding the Banks Peninsula Marine Mammal Sanctuary to include the area from Motunau to Timaru with a total ban on commercial and recreational gill netting in the extended sanctuary.
3. Further research by the Department of Conservation aimed at developing more marine mammal sanctuary’s and a ban on set netting to protect the dolphin populations on West Coast of the South Island and in Southland.
4. Rejection by the Minister of Fisheries of proposals to increase the elephant fish catch limit.
Department of Conservation and Ministry of Fisheries (1994) Review of the Banks Peninsula Marine Mammal Sanctuary: A paper for public comment. June 1994. Canterbury Conservancy Misc Report Series No 3. 34p.
Department of Conservation (comp) (1992) Banks Peninsula Marine Mammal Sanctuary Technical Report, July 1992. Canterbury Conservancy Technical Report Series 4. 84p.
Dawson S M and Slooten E (1993) Conservation of Hector’s dolphins: The case and process which led to establishment of the Banks Peninsula Marine Mammal Sanctuary. Aquatic Conservation: Marine and Freshwater Ecosystems Vol 3: 207-221.
(1996) Down-under dolphins – the story of Hector’s dolphin. Canterbury University Press. 60p.
Dawson S M, Read A and Slooten E (1998) Pingers, Porpoises and Power: Uncertainties with using Pingers to reduce bycatch of small cetaceans. Biological Conservation 84: 141-146.
Martien, K K, Taylor B L, Slooten E and Dawson S (1999) A sensitivity analysis to guide research and management for Hector’s dolphin. Biological Conservation 90:183-191.
Pichler F B, Dawson S M, Slooten E and Baker C S (1998) Geographic isolation of Hector’s dolphin populations described by Mitochondrial DNA sequences. Conservation Biology 12:676-682.
Slooten E and Lad F (1991) Population biology and conservation of Hector’s dolphin. Canadian Journal of Zoology 69: 1701-1707.