CHAPTER 15 - COASTAL AND MARINE SPECIES

Commercial Utilisation of Australian Native Wildlife

CHAPTER 15 - COASTAL AND MARINE SPECIES

15.1 Many marine species are exempt under the Wildlife Protection (Regulation of Exports and Imports) Act 1982. The notable exceptions are coral, shells, jelly-fish and beche-de-mer, the export of which is regulated by the Act. [1] With the exception of the large commercial fisheries, most marine-based industries in Australia are small and very localised.

15.2 There is a small but culturally important industry based on the commercial use of muttonbirds, primarily by Aboriginal people on the Islands of Bass Strait. The industry has local and export markets in meat, oil and feathers but is currently in decline due to lack of market development. Despite having sustained a commercial harvest for many decades, populations of muttonbirds are increasing and the industry has played an important role in habitat retention.

15.3 As yet there is no turtle industry, but possibilities are being investigated in Northern Territory. There are a number of industries in Australia based on the sale of invertebrate marine life, including coral, shells, pearls, jellyfish and seaweed. Coral and shell products are sold primarily to tourists, but there is a small trade in specimen-grade shells to collectors. The types of products sold include whole sea shells, coral pieces, preserved marine life (eg. sea stars), craft products and gift ware, jewellery and marine fossils. Most businesses dealing in coral and shells also sell inexpensive gemstones. A variety of coral and shell species can be commercially collected in Australia, under licence agreement, and sold either individually or as part of a craft product.

15.4 Pearls are farmed in a number of coastal locations, but the largest are located off the shores of Western Australia. There are small industries harvesting edible jellyfish in coastal areas of NSW and an industry based on harvesting seaweed along the coast of Tasmania.

Muttonbirds

The Industry

15.5 The muttonbird, or short-tailed shearwater (Puffinus tenuirostris), is a migratory seabird that visits coastal areas of south-eastern Australia between September and April each year to breed. While most of coastal south-eastern Australia supports breeding colonies, the vast majority of rookeries occur in Tasmania. Commercial use of muttonbirds commenced with the arrival of European settlers and for a while was an important part of the economy of islands in Bass Strait. [2] It is now confined mostly to Aboriginal people who earn an income from the annual harvest. Aboriginal people have harvested muttonbirds in Bass Strait for centuries and there is a continuing but diminishing tradition associated with the harvest. Although the season is short, it is important to Aboriginal people as it forms a significant link to traditional social and cultural activities. [3]

15.6 There are about 290 muttonbird colonies in south eastern Australia containing about 23 million breeding birds. [4] Muttonbirds nest in a burrow and adult females lay only one egg. Their breeding cycle and migratory pattern is highly predictable and their life span is about 20 years. According to the 1994 Bureau of Resource Sciences publication Commercial use of wild animals in Australia, these characteristics have probably contributed to the ability to harvest muttonbirds in a sustainable manner.

15.7 The muttonbird is protected in all parts of Australia except Tasmania where chicks can be taken under licence issued by the Tasmanian Parks and Wildlife Service. Adult birds are fully protected. The harvesting season lasts from 27 March to 30 April each year. While there is no bag limit for commercial licences, the limit for non-commercial use is 50 birds per day on Bass Strait Islands and 15 birds elsewhere. Although more than one million chicks are taken each year, no rookery which has been subject to commercial exploitation has been destroyed. However, ironically, some rookeries subject to non-commercial harvesting have been severely damaged through overharvesting, damage to habitat, litter, poaching, anti-social behaviour and general abuse of regulations.

15.8 As soon as muttonbird chicks are removed from their burrows their necks are broken. They are then threaded onto a spit and carried back to a nearby shed for processing. The major commercial rookeries have processing sheds and these are regularly inspected and approved by the Tasmanian Department of Health. After removal of feathers and draining of proventricular oil, the carcasses are eviscerated, cleaned and preserved in a strong salt brine.

15.9 Almost all muttonbird oil is purchased by the racehorse industry where it is used as a food supplement for horses. A small amount is used by the leather industry as the oil is especially good for softening and preserving leather. Feathers are sold to bedding manufacturers for inclusion in pillows and quilts. In 1990, the total value of muttonbird oil produced was about $12,000 and feathers was about $5,300.

15.10 Salted muttonbird meat is very oily and although it is considered to be an acquired taste, it is not sold as a gourmet food. Most of the catch is distributed in Tasmania and the only export is to New Zealand. A small proportion may go to other mainland areas of Australia. Difficulty of refrigeration, high transport costs, low consumer image resulting in low unit cost and the very short harvesting season combine to seriously limit potential for industry expansion. In fact, the taking of muttonbirds, both for commercial and non-commercial purposes, has declined considerably in recent decades. In the early 1980s, for example, over 4,000 non-commercial licences were issued. By 1990 this had dropped to 470.

Current Evidence

15.11 In evidence to the Committee, Mr Greg Hocking, a Tasmanian wildlife biologist, told the Committee that over the years populations of muttonbirds have fluctuated, but their harvesting has remained sustainable, although in recent years the size of the harvest has declined significantly. [5] Commercial harvesting is now primarily confined to the Furneaux and Hunter groups of islands in Bass Straits.

15.12 More importantly perhaps, is the suggestion that the commercial use of muttonbirds has led to the protection of their habitat which would otherwise have been used for grazing. In the 1994 Bureau of Resource Sciences report on Commercial Use of Wild Animals it was stated:

Muttonbirds have been managed as a renewable resource for many decades. An indication of the positive conservation implications for sustainable use of muttonbirds (and perhaps other native species) is evidenced by the lack of 'improvement' of lands where shearwater colonies exist. Recognition of the economic value of muttonbirds by landowners has undoubtedly played a role in conserving colonies. [6]

15.13 This view was confirmed more recently in evidence to the Committee when, in response to a question from Senator Calvert, Mr Hocking commented:

… it is probably worth noting that some of the first reserves that were created up in those islands [in Bass Strait] … were for mutton birds … That had the effect of reserving those islands from other land uses, including grazing. [7]

15.14 Mr Vincent Serventy, noted conservationist and President of the Wild Life Preservation Society of Australia, also commented in evidence to the Committee:

I was involved in the research on the short-tailed shearwater, the so-called muttonbird. That has been kept going because it was the only cash crop to the Aborigines. But a strange thing happened. It was because of the Aborigines that the short-tailed shearwater is now in huge numbers and increasing in numbers. Despite the fact that they are taking half a million chicks each year, their numbers are actually increasing. … That has meant that we have a sustained industry and will be able to harvest shearwaters forever,so long as we do not pollute the seas and destroy all the krill they feed on, of course. [8]

Industry Potential

15.15 Although the muttonbird industry plays an important local social and economic role, it is poorly coordinated and lacks infrastructure and market development. In addition, there are problems with supply matching demand. Industry expansion would require the stabilisation of supply to traditional domestic and New Zealand markets, and from there expansion into potential niche markets in Asia.

Objections to Muttonbirding

15.16 ANZFAS is opposed to the harvesting of muttonbirds on the basis that 'the birds will not be taken by all catchers at all times in a humane manner'. [9] ANZFAS also objects because, as with the exploitation of all native species, the harvesting of muttonbirds is 'non-essential' in terms of the product itself. With regard to the needs of Aboriginal people, ANZFAS believes that 'their psychological satiation should not be dependent on the brutal death of thousands of shearwater chicks'. [10] ANZFAS acknowledges that muttonbird populations are not threatened by overharvesting but points out that there are many unpredictable threats to birds such as predation, disease, starvation and global warming. For three main reasons, ANZFAS recommends the cessation of commercial muttonbirding: the inherent cruelty of harvesting, the increasing irrelevance of the industry and the unknown extent of external threats.

15.17 In its submission to the Committee, Animal Liberation (ACT) expressed concern about the inhumane treatment of muttonbirds, claiming: 'Muttonbirds are pulled brutally from their burrows and their necks are broken, frequently by unskilled people or people (including children) not strong enough to do the job effectively. This is done in front of the parent birds who raise only one chick each year and who undoubtedly suffer appalling emotional distress'. [11] Animal Liberation (ACT) also expressed concern that although the current level of harvesting appeared to not threaten the populations of muttonbirds in Bass Straits, given other environmental threats facing the seas and coastlines, it was only a matter of time before a sudden and disastrous decline in numbers of muttonbirds occurred, as had happened off the coast of California to a related species of shearwater. [12]

Turtles

15.18 The Hawksbill turtle (Eretmochelys imbricata) is a marine species which, according to both the Northern Territory Government and Wildlife Management International, is suitable for commercialisation through ranching. Preliminary research carried out in Darwin by Wildlife Management International has indicated that the species can be raised efficiently in captivity and the quality of the shell improved by the raising regime. Techniques have been established to collect, transport and incubate ranched eggs and to house juveniles in captivity. There is export potential for meat and skin with well established markets in Japan where the shell has been used for over 400 years. Populations of the Hawksbill turtle are considered to be 'healthy' in Australia. However, the species is listed on Appendix I of CITES and would need to be moved to Appendix II before international trade was permitted. Development of the project is now constrained by uncertainty as to whether the Federal Government will support such a proposal to CITES. [13]

Coral

15.19 Most stony or hard corals throughout the world have been listed on CITES Appendix II as endangered. With the exception of the Philippines where the coral industry is unchecked and over-collection is rampant, the threat to coral diversity and abundance comes not from commercialisation, but from physical and chemical changes to the marine environment (such as siltation and excess nutrients flowing out from rivers) and from ozone depletion which may eventually cause substantial mortality of intertidal corals. [14]

15.20 The export of all Australian native corals for private or commercial purposes is prohibited under the Wildlife Protection (Regulation of Exports and Imports) Act 1982. This includes raw and polished coral, coral jewellery, craft and tourist items which include coral and native artefacts which incorporate coral pieces. A permit to re-export coral may be issued provided it can be established that the coral was imported legally.

15.21 Because most coral species growing in Australian waters are listed under CITES as endangered, the coral industry in Australia is quite small with an annual harvest of only about 50 tonnes. In Queensland, any one operator is allowed to harvest up to four tonnes per year. After a cleaning process, the coral is presented for sale in shops or used in other products. However, while coral stems and coral products can be purchased and taken anywhere within Australia, they cannot be exported and this causes a number of difficulties in selling coral to tourists.

15.22 Mr Walker, owner of the business Nature's Gemhouse in Cairns, expressed a great sense of frustration with the current system:

… until about a year ago, [coral] was going out and Customs was turning a blind eye to it. About six months ago, they started enforcing it. They are selectively enforcing it. If it is a large ornamental piece of coral, they confiscate it from the tourists at the airport. If it is a small piece of coral or it is incorporated into a souvenir, they let it go. If you pack it into your suitcase, it probably goes through. If you take it in your hand luggage, it gets confiscated. We are perfectly entitled to sell it legally in the street, but we get a hell of a lot of unhappy tourists when they get to the airport. [15]

15.23 Mr Walker suggested that while many Australian corals are robust and are not threatened, there is a public perception that coral reefs are fragile and under threat. Mr Walker has a permit to remove a small amount of brown stem coral from the reef outside Cairns for commercial purposes. As with marine animals such as molluscs, once a piece of coral is harvested from the ocean it is no longer alive. To Mr Walker, there is no logical reason why coral fragments, once removed from the reef, can be transported all over Australia, but not out of Australia.

15.24 Mr Walker argued in his evidence to the Committee that the Great Barrier Reef is in good condition, largely due to its size, its remoteness, and the efforts of the Marine Park Authority. In Mr Walker's opinion, the future of the industry lies in his ability to export coral products. There is a large potential in tourists wishing to take coral out of the country but that is hampered by current federal legislation. In the hope of eventually avoiding problems with harvest licences and export permits, Mr Walker is currently experimenting with artificial culturing of corals (mariculture). He believes that this will allow him to produce the size and shape of product required, conveniently close to population centres and, as with other 'farmed' species, he would be able to harvest without any impact on natural coral habitat.

15.25 The Pet Industry Joint Advisory Council (PIJAC) also expressed the view that the ban on the export of corals was anomalous and unnecessary, and recommended that the ban be lifted. [16]

15.26 The Committee agrees that there are some anomalies in the regulations relating to the sale and export of coral. Given that coral is dead once it is removed from the sea and given that it has been collected under a legitimate permit system which has quotas attached to it, there appears to be no rationale in differentiating between a person buying a piece of coral and taking it to Tasmania and a person buying a piece of coral and taking it to New Zealand, except that Australia is formally complying with a CITES listing. This compliance, however, has no beneficial impact on the conservation value of that species, nor on its habitat. Permission to harvest and to sell has already been given. The only impact that the ban on export appears to have is a negative impact on the economic viability of a business. The Committee notes, however, that the Queensland government has prepared a management plan for corals as required by the Wildlife Protection (Regulation of Exports and Imports) Act 1982, which is currently being considered by Environment Australia.

Shells

15.27 The export of most Australian native molluscs and their shells is regulated under the Wildlife Protection (Regulation of Exports and Imports) Act 1982 and to export any shell, regardless of its age, a permit must be issued by Environment Australia. Permits to export shells and shell products may be granted where the specimens have come from a captive breeding operation, or from a harvesting or ranching operation approved by Environment Australia. While a few mollusc species are exempt under Schedule 4 of the Act, the bulk (12,000 species) are not.

15.28 The practical effect of the legislation is that a retailer can sell an unlimited number of shells without a permit, so long as they are not exported. For each tourist wishing to take one or more shells out of Australia, the retail shop must obtain a permit from the office of the Department of Environment in Canberra.

15.29 Mr Walker argued in his submission that this was a massive waste of resources, particularly for species that were not endangered. [17] In his opinion, the consequence of this was not the conservation of molluscs, but the curtailment of an export industry: ' … the crime is not utilizing the species, but trying to earn a living by earning export dollars …'. [18]

As a taxpayer I ask why we are wasting federal and industries resources doing this when there are so many real and serious issues to address with our limited resources? The international community does not require CITES permits for non endangered species. [19]

15.30 With regard to marine shells, Mr Walker made the following recommendation:

Remove non-endangered marine molluscs from the CITES umbrella and require that people who trade domestically or internationally in Australian shells are licensed and required to issue a standardised invoice with each sale. At the conclusion of each month either a summary of what is sold or duplicate invoicing to be submitted to a central data collection point. [20]

15.31 The Committee notes, however, that the Department of Environment has on a number of occasions over the last decade tried to determine which species of shells are at risk from trade. According to the Department, 'unfortunately none of the reviews have come to a conclusion that is accepted by industry, and therefore there has not been an agreed list of which species we should keep strict control over the trade on, and which species we can ease off on'. [21] The Department believes that some of the more valuable species (such as the cowries) are at risk from collection. In an effort to resolve this problem, Environment Australia has commissioned a study by the Australian Museum on the levels of take of the various shell species and the potential risk from trade in an attempt to determine which species require control.

Pearls

15.32 Oyster pearls (Pinctada maxima, the giant Australian oyster) are cultivated in a number of places around Australia. The oldest and largest pearl farm is at Kuri Bay at Point George, near Broome on the north coast of Western Australia. Owned by Paspaley Pearls, the lease holds more than 150,000 seeded oysters. Those shells which do not produce pearls are sold for oyster shell meat and mother-of-pearl. Each oyster bears three or at the most four pearls, one every two years, by which time the pearl has grown to between 8-18mm.

15.33 Pearlers work in two week shifts during which time they live on boats at the lease sites. Pearling is labour intensive and involves a variety of manual tasks (cutting off shell edges, cleaning shells, and removing and cleaning pearl meat). It also requires technicians, who must have at least six year's experience, to seed the pearls. Up to 5,000 pearls a day are seeded by each technician with Mississippi clam shell fragments.

15.34 The pearl industry generates exports of more than $200 million annually. Historically, the industry in northern Western Australia has had a strong input from Japanese pearlers and there is a festival held in Broome in August each year to celebrate the Pearl (the Shinju Matsuri Festival). [22]

Edible Jellyfish [23]

15.35 Jellyfish of the species Catostylus mosaicus [24] are harvested in New South Wales oceanic and estuary waters and dried to form a food product which is exported as a Controlled Specimen under Section 10(A) of the Wildlife Protection (Regulation of Exports and Imports) Act 1982. The harvesting and sale of jellyfish is an emergent industry in Australia and its economic viability is unknown. The environmental impacts of harvesting jellyfish are also unknown.

15.36 Jellyfish have a broad range of potentially important ecological roles, including:

15.37 The benthic life-phases of the species also have important ecological roles because they are:

15.38 Further work is needed on the ecology and population dynamics of the species to determine with certainty any potential environmental impacts that large-scale harvesting may have. Ecologically sustainable levels of harvesting are yet to be determined and Environment Australia is currently funding further research which is aimed at addressing these questions, as well as elucidating the seasonality of breeding and latitude effects.

15.39 The North Coast Environment Council is opposed to the harvesting of various marine species (jelly fish, sea cucumbers, molluscs, etc) on the basis that insufficient research has been carried out on the environmental impact of harvesting, and because it is almost impossible to monitor illegal activities. The Council believes: 'it is reasonable to assume that the removal of large numbers of common species will cause a huge imbalance, occasioning irreparable damage to the marine environment'. [25]

Seaweed [26]

15.40 A variety of species of Australian marine macro-algae and marine angiosperms (seagrasses) are, or have been harvested for export. [27] The harvested product is often sold simply as dried or granulated seaweed, although marine macro-algae may be processed further to produce alginates and agar. Algae are used as a source of food for humans and stock, including abalone, and as a fertiliser. Seagrasses have been harvested for use as house insulation (historical) and as soil improvers. Interestingly, the kelp Undaria pinnafitida, which was accidentally introduced to Australian waters from Japan, is now being harvested for export back to Japan as food which may help to contain the spread of this species.

15.41 Seaweeds such as kelp are usually harvested as beach wrack. The harvesting of beach wrack increases the amenity value of beaches for humans, as decomposing beach wrack produces sulphide gas and plagues of beach flies. However, while beach flies are a nuisance to humans, they are an important source of food for insectivores, particularly species of shorebirds. Beach wrack is an important source of recycled nutrients and detrital material which forms the basis for primary production and food chains in nutrient poor coastal waters. Beach wrack also plays an important role in dune formation. The organisms which use beach wrack to breed and feed seem to be opportunistic and no species is known to be ecologically dependent on such material. Indeed, the unpredictability of deposition of beach wrack would make an ecological dependence on such material a very precarious life-strategy.

15.42 Alternatives to harvesting beach wrack are direct harvesting of living stocks and mariculture. Direct harvesting, being more intrusive, may have a greater impact on the breeding population of algae and seagrasses. Intensive mariculture of seaweeds is not currently considered to be economically feasible in Australia due to the high capital and labour costs, but there is interest in experimental studies with growing kelp on ropes.

15.43 The business Kelp Industries, which is based on King Island, has been harvesting bull kelp (Durvillaea potatorum) for export for some 24 years. The kelp processing factory, which exports its product to the United Kingdom for further processing, supplies one fifteenth of the world's known requirements for alginates, and makes a significant contribution to King Island's economy.

15.44 Harvesting of beach cast seagrass does not appear to be as economically viable as harvesting kelp, but the growing abalone mariculture industry is creating an increasing demand for subtidal and intertidal drifting seaweeds as a food source.

15.45 Marine macro algae and angiosperms harvested from Tasmania (including Durvillaea potatorum from King Island) and Posidonia australis harvested from Lacepede Bay, South Australia, are exported as Controlled Specimens under Section 10(A) of the Wildlife Protection (Regulation of Exports and Imports) Act 1982.

Aquaculture

15.46 Aquaculture of freshwater crayfish is expanding rapidly with interest primarily in three species: marron, yabby and redclaw. Concerns include the need for stringent controls to prevent escape into the wild of translocated species, and the need for regulation to prevent commercial threats to wild populations. [28] Aquaculture of a number of other native species is currently being investigated including abalone, prawns, trout, barramundi and eels. There is increasing interest in inland production of marine fish (for example, snapper, mulloway, black bream, and silver perch). [29]

Summary and Conclusions

15.47 With the exception of the large offshore commercial fisheries, most marine-based industries in Australia are small and very localised. There is a small but culturally important industry based on the commercial use of muttonbirds, primarily by Aboriginal people on the Islands of Bass Strait. The industry has local and export markets in meat, oil and feathers but is currently in decline due to lack of market development. Despite having sustained a commercial harvest for many decades, populations of muttonbirds are increasing and the industry has played an important role in habitat retention. Animal rights groups object to muttonbirding on the basis of cruelty.

15.48 There are a number of industries in Australia based on the sale of invertebrate marine life, including coral, shells, pearls, jellyfish, and seaweed. Coral and shell products are sold primarily to tourists, but there is a small trade in specimen-grade shells to collectors.

15.49 Because most coral species growing in Australian waters are listed under CITES, their export for private or commercial purposes is prohibited under the Wildlife Protection (Regulation of Exports and Imports) Act 1982. While harvesting permits are issued to local operators and coral can be sold for domestic use, it cannot be taken out of the country. To industry, this is illogical and represents a significant hindrance to its expansion. The Committee notes, however, that the Queensland Government has prepared a management plan for corals as required by the Wildlife Protection (Regulation of Exports and Imports) Act 1982 which is currently being considered by Environment Australia.

15.50 Most molluscs are also listed under CITES and permits must be issued by Environment Australia for the export of most Australian native molluscs and their shells. To industry, this is a waste of resources, particularly for species that are not endangered. The Committee agrees that there are some anomalies in the regulations relating to the sale and export of coral and shells and notes that difficulties associated with their export have a negative impact on the economic viability of business. The Committee notes, however, that Environment Australia is currently investigating these issues. The Committee believes that the Government should act wherever possible to support legitimate small businesses in Australia and thus recommends that Environment Australia give priority to resolving problems relating to the sale and export of coral and shells so as to assist industry.

15.51 While industries based on the harvesting of various marine species (jelly fish, seaweed, sea cucumbers, molluscs, etc) are small and highly localised, some conservation groups objected to them on the basis that insufficient research has been carried out on the environmental impact of harvesting, and because it was difficult to monitor illegal activities.

15.52 Aquaculture appears to be expanding rapidly with interest in a range of marine and freshwater species. Concerns include the need for stringent controls to prevent escape into the wild of translocated species and the need for regulation to prevent commercial threats to wild populations.

15.53 Preliminary investigations suggest the Hawksbill turtle (Eretmochelys imbricata) is suitable for commercial development through a ranching program and export of products. Development of the project is currently constrained by uncertainty as to whether the Federal Government would support such a proposal.

Footnotes

[1] Evidence, p. RRA&T 17, 50.

[2] Unless acknowledged otherwise, the following information has been taken from the Bureau of Resource Sciences publication Commercial use of wild animals in Australia, by Brian J Ramsay, AGPS Canberra, 1994, ISBN 0644297751.

[3] Aboriginal People and Muttonbirding in Tasmania by Irynej Skira, Chapter 12 in Sustainable Use of Wildlife by Aboriginal Peoples and Torres Strait Islanders edited by Mary Bomford & Judy Caughley, Bureau of Resource Sciences, AGPS A62208, 1996, p. 167.

[4] Bomford & Caughley, op cit, p. 167.

[5] Evidence, p. RRA&T 895.

[6] Ramsay, op cit, p. 69.

[7] Evidence, p. RRA&T 896.

[8] Evidence, p. RRA&T 820.

[9] Submission No. 178, p. 16.

[10] Submission No. 178, p. 17.

[11] Submission No. 66, p. 3.

[12] Submission No. 66, p. 7.

[13] Letter dated 1 June 1998 from Mr Charlie Manolis, Wildlife Management International, p. 1; Evidence, p. RRA&T 340.

[14] Submission No. 302, p. 5.

[15] Evidence, p. RRA&T 246.

[16] Evidence, p. RRA&T 690, Submission No. 332, p. 12.

[17] Supplementary Submission No. 302, p. 6.

[18] Letter dated 4 September 1984 from Mr Ray Walker to the Federal Minister for Trade and Resources, p. 2, attached to Submission No. 302.

[19] Supplementary Submission No. 302, p. 7.

[20] Submission No. 302, p. 5.

[21] Letter dated 5 May 1998 from Dr Tony Bigwood, Director, Wildlife Population Assessment Section, Environment Australia.

[22] Angie Buttrose Getting precious, Panorama Magazine, May 1997, pp 71-75.

[23] The following case study is taken from the submission provided by the Department of Environment, p.63-64.

[24] The organism harvested is the medusa phase (i.e. jellyfish) of the Cnidarian species Catostylus mosaicus (Class Scyphozoa, Order Rhizostomeae).

[25] Submission No. 22, p. 2.

[26] The following case study is taken from the submission provided by the Department of Environment, p.64-66.

[27] Species harvested include: Durvillaea potatorum, Ecklonia radiata, Macrocystis pyrifera, Macrocystis angustifolia, Sargassum spp., Gracilaria spp., Gelidium spp., Posidonia spp., Zostera spp., and Heterozostera spp.

[28] Geddes, Michael & Jones, Clive 1997 Australian freshwater crayfish: exploitation by fishing and aquaculture. Australian Biologist 10(1):70-75.

[29] For more detail on each of these ventures see: 1998 The New Rural Industries - A Handbook for Farmers and Investors, RIRDC Canberra, edited by K W Hyde, ISBN 0642246904.