Endangered whitebait species bred in Warkworth hatchery
Extinction threat extinguished, Aquaculture opportunity started
Dr. John Walsby
Mahurangi Technical Institute (MTI), based in Warkworth, has chalked up another first by successfully breeding huge numbers of one of New Zealand’s rarest native whitebait species, the Giant Kokopu (Galaxias argenteus) from captive bred fish in its conservation hatchery.
Internationally MTI is recognised as a fish conservation hatchery for its break-through successes in eel breeding, and for over 20 years has bred the many millions of grass carp and silver carp used throughout New Zealand for clearing nuisance pond weeds and algae from lakes. During the last ten years MTI aquaculture scientists and students have been investigating the breeding of many of New Zealand’s native fish including the 6 species that make up the New Zealand whitebait catch.
It is widely accepted that it is the presence of Giant Kokopu whitebait in the South Island West Coast catches of whitebait that give them their renowned, superior flavour but in conservation circles there is alarm that this important native fish is in serious decline. The Red List of the International Union for the Conservation of Nature’s (IUCN) ranks Giant Kokopu as Vulnerable which means they are “facing a high risk of extinction in the wild”.
Giant kokopu embryo © Stephen Moore, Landcare Research for Mahurangi Technical Institute
From their tiny beginnings, Giant Kokopu grow into New Zealand’s most impressive native freshwater fish. Sometimes dubbed the “New Zealand native trout”, adults can grow to 2 kg and exceed half a metre in length. With fine dappled markings of rings and crescents over a dark background, and a delicate scatter of gold spots, the Giant Kokopu, is a handsome specimen but is seldom seen because of its rarity. MTI’s breeding success is especially remarkable because the parents were themselves hatched at MTI’s laboratory from a small cluster of eggs collected in the wild four years ago. Hatching the eggs, raising the larvae and growing the juveniles through to sexually mature adults from which offspring have been produced, is recognised as a major achievement. It is the first demonstration of what fish scientists term, “closing the life cycle”; producing a second generation from fish hatched and raised in a hatchery.
The precise details of natural breeding by Giant Kokopu in the wild have not been reported by fish scientists and have been the subject of much speculation for many decades. In the absence of clues from the wild, the current achievement by MTI to have both spawned and hatched many thousands of this rare New Zealand native freshwater fish in its hatchery is considerable. Mr. Paul Decker, of MTI, said “These are our grandchildren whose parents were our first born”. Although the mechanics of fish egg fertilisation are not complicated, creating the right conditions for the synchronised production of good quality, fully mature eggs and milt (fish semen), requires careful culturing and monitoring of the parent fish.
“Hatching the eggs is also a painstaking procedure to ensure that they are not physically damaged, and are protected from diseases and attack by micro predators. Throughout the incubation period it is also critical that the eggs are kept in ideal conditions with temperature, moisture and aeration levels that suit them”.
Mr. Decker continued, “A major part of the breeding success has been to achieve the hatching and larval raising on such a large scale. We are now in our 4th week of breeding and are hatching literally thousands upon thousands of Giant Kokopu whitebait every 21 days after egg laying. With production at these levels security of supply for commercial whitebait farming can now be assured”.
“Within the next 10 weeks the juveniles will have grown to what the public recognise as “whitebait” and some of our aquaculture students and staff will be taste testing samples of these delicious fish.”
Hatchery produced fish fry for use in aquaculture must be healthy and have high survival rates. Poor incubation and larval raising conditions can produce weak offspring but according to Mr. Decker, “The fry being raised at MTI’s hatchery are already showing excellent health and because of precautions taken, they are disease free.” This will be invaluable for stock that is grown on for commercial whitebait production but also for stock that is to be released into the wild for conservation enhancement projects. In the past survival of transferred fish from other sources has often been below expectations due to health issues.
MTI sees two distinct but complimentary benefits to New Zealand from the hatchery breeding of Giant Kokopu:
· The first is for conservation with the goal being to release adult fish back into restored natural waterways that have yet to be re-colonised by this iconic endangered native fish species.
· The second is their commercialisation, as a farmed whitebait fish to meet the demand for such dishes as whitebait fritters in the home and restaurant market. For this, culture could be on a year round basis to make farming of this delicacy commercially viable.
MTI, New Zealand’s first aquaculture teaching college, has long regarded its Warkworth facility as a “conservation fish hatchery”. In this role it is already involved collaboratively with the Department of Conservation in reintroductions of native fish to natural habitats and with the Auckland Zoo to assist with native fish breeding and to display native fish to raise their public profile. Even the farming of whitebait has potential conservation benefits because it will reduce commercial harvesting pressure on natural populations enabling them to recover. “This is a win - win for New Zealand” said Paul Decker “because it demonstrates that conservation and commercial initiatives can be complimentary.”
2012 Annual Meeting of the Freshwater Fish Specialist Group
For a few days in early May, sixty-five (65) of the world’s leading freshwater fish specialists assembled in the historic town of Chester. This international delegation, representing 18 countries, gathered for the annual meeting of the FFSG: its theme for 2012 being “Global challenges in caring for and conserving freshwater fishes”.
32,000 and counting…
One astounding fact to emerge from the meeting was the sheer number of fish species – marine and freshwater – that have been discovered and described in recent years. For example, since 1976, nine thousand (9000) species have been added to the growing list of known fish species living today (currently around 32,000 species) - that averages almost 5* new fish species every week! And there’s no sign of a slow-down: for in the first four months of this year, a further 75 new species of fish were described, most being freshwater species.
*4.8 to be more precise.
Species in decline
While new fish species are continually being discovered, sadly many others are facing extinction. According to the IUCN’s “Red list” for fish (Red lists are inventories of the World’s threatened animals and plants), over 75% of threatened fishes are freshwater species.
Major threats to the World’s freshwater fish populations were discussed during the meeting, and included: water pollution; deforestation; over-fishing; and water extraction for irrigation. Case studies were presented for several important freshwater fish regions including Ghana, The Gambia, Brazil, Mexico, Mekong Basin, India, Japan, Arabian Peninsula, and Australia. Clearly, freshwater fishes are under threat in all parts of the globe.
By Peter Burgess
The full article will be available in the next issue of the Practical Fishkeeper
4th International Zoo and Aquarium Symposium ‘Global Freshwater Fishes: linking in situ and ex situ actions’
Fifty-five freshwater conservation biologists, research scientists, and specialists from zoos and aquariums, from 21 countries, met in Chester, UK in November for the 4th International Zoo and Aquarium Symposium ‘Global Freshwater Fishes: linking in situ and ex situ actions’. The meeting was hosted by Chester Zoo, the North of England Zoological Society and was held in conjunction with the 7th Annual Meeting of the IUCN Species Survival Commission / Wetlands International Freshwater Fish Specialist Group.
The meeting provided an unprecedented opportunity for this diverse mix of specialists to combine their skills to promote conservation of freshwater fishes in their habitats; and to advance projects at public aquaria that raise public awareness and financial support for conservation, and that support conservation through species breeding programmes. Specific projects will be identified for priority species in a number of regions globally, linking in situ actions (i.e. conservation actions within the natural habitat and range of the species) and ex situ actions (i.e. actions that occur outside the habitat and range, though conservation breeding, or other mechanisms to raise awareness for and promote conservation of the species).
Professor Gordon McGregor Reid, Chair of the Freshwater Fish Specialist Group and Immediate Past President of the World Association of Zoos and Aquariums stressed the important role that zoos and aquariums can play. “Each year, more than 700 million people visit zoos and aquariums worldwide – a bigger attendance than all football games! Because of this, zoos and aquariums give $350 million annually directly to field projects. What we need to know is how to take the most effective actions, in the most important areas.” The participants affirmed the important role of zoos and aquariums in supporting in situ conservation, as well as properly planned and informed ex situ programmes.
In his address to the meeting, Dr. Simon Stuart, Chair of the IUCN Species Survival Commission, emphasized that “there is a significant and growing challenge ahead to conserve freshwater habitats and species, and it is important to consider all the options that are available to conservationists to prevent or reduce negative impacts.” Dr. Stuart attended the conference to present the results of the 10th Convention of Parties of the Convention on Biological Diversity (CBD), held in Nagoya in October, where the 185 countries that are signatories to the Convention agreed upon the targets for the conservation of the world’s biodiversity over the next 10 years. Greater protection for inland waters and sustainable management of inland fisheries are now, for the first time, specifically mentioned in a number of the CBD targets. This calls for a significantly increased investment in research, conservation planning, and management in inland waters.
An immediate action for the IUCN SSC/WIFreshwater Fish Specialist Group is supporting the Ramsar Convention on Wetlands. The Freshwater Fish Specialist Group has an extremely valuable opportunity to contribute to this Convention, specifically through advising on fish-related criteria for recognizing Ramsar conservation sites.
All participants at the meeting highlighted the desperate need for conservation action for many species of freshwater fishes around the world. Results from the IUCN Red List of Threatened SpeciesTM, presented by Dr. William Darwall, from IUCN’s Species Programme in Cambridge, UK, showed that the world’s freshwaters are among the most threatened of all habitats, and freshwater fishes are being severely impacted. He stated: “Nevertheless, we still lack basic data on the biological diversity of many freshwater habitats around the world, and the threats they face.” More action on assessing the risk of extinction to species, as defined through the criteria used in the IUCN Red List, is urgently needed.
Two new species of freshwater fishes discovered in Vanua Levu now internationally recognized.
Two new scientific papers have been published in the last several months highlighting the discovery of two new species of freshwater fishes unique to Fiji and only known from two river systems in Vanua Levu. Wetlands International –Oceania staff Aaron Jenkins and Kinikoto Mailautoka, made the new discoveries as part of surveys for the Ecosystem Based Management project over the last several years. For more information, click here
2011 Fisheries Society of the British Isles Annual International Conference "Fish Diversity and Conservation: current state of knowledge"
is taking place in Bournemouth, UK from 18th-21 July. The link to the conference website is: http://www.fsbi.org.uk/2011/home/