Tuesday, July 18, 2017

19/07/2017: Sustainable farming of lobsters: A dream soon to become a reality?

by Associate Professor Greg Smith, University of Tasmania, Director of the ARC Research Hub for Commercial Development of Rock Lobster Culture Systems at the Institute for Marine and Antarctic Studies (IMAS)

Spiny lobsters, also known as rock lobsters in Australia and New Zealand, are one of the few high value marine species that are yet to be cultured in commercial hatcheries
The appeal of culturing spiny lobsters is due to favourable market attributes including the fresh product’s high value in the Asian market, increasing product demand and the static nature of current wild fishery.

Image credit: IMAS

Research into the biology of spiny lobsters is not new, with initial propagation studies undertaken in Japan in the 1800s. The larval phase of up to seven species was completed in Japanese laboratories between 1960 and 2000.

Spiny lobster propagation research has since been undertaken in a number of countries including Australia, New Zealand, Vietnam, India, America, Mexico and England. For the last two decades, larval propagation research has been focused in Australia and in recent years at the University of Tasmania’s Institute for Marine and Antarctic Studies (IMAS), in Hobart.

Australian lobster research has had long-term government support through the Fisheries Research and Development Corporation (FRDC), the Tasmanian Government, the Australian Research Council (ARC) and private equity.

The current research program at IMAS focuses on commercialisation of the hatchery technology supported by an ARC grant of US$5 million through the Industrial Transformation Research Program.

The ARC funding targets collaborative research between industry partners and Australia’s best researchers. The ARC Research Hub for Commercial Development of Spiny Lobster Culture Systems is a collaboration with the University of Tasmania, University of Auckland (New Zealand), University of the Sunshine Coast, and Australian industry partner Plastic Fabrications Group.

The research programme is supported by the Tasmanian Government through the Sustainable Marine Research Collaboration Agreement. While there have been challenges to overcome in the hatchery production of seed stock, the grow out sector has been established since the 1990s, primarily in Vietnam, with some recent activity in other countries in the region including Indonesia.

Despite the larval phase of many species of spiny lobster being completed in research laboratories, until recently, there has been a failure to translate the small-scale research success into commercial processes.

As a result of there being no hatchery production of spiny lobsters seed stock, aquaculture is based on the collection of wild seed stock. The larval cycle of spiny lobsters is protracted; typically females mate in inshore waters and carry a fertilised bundle of eggs externally attached under their tail.

While attached to the female the eggs develop for a period of between weeks and months, depending on the species, and then hatch as underdeveloped larvae (phyllosoma). To sustain a static population, spiny lobsters focus their reproductive energy in the investment of large numbers of offspring.

In the wild, each breeding female will hatch millions of phyllosoma, but with a long larval duration, small numbers survive to reach juvenile and later adult stages. Phyllosoma reside within the water column and are transported into the open ocean by currents and eddies, they have very limited swimming ability.

In offshore waters, and often at depth, the phyllosoma will undertake the complex larval development phase, including up to 24 individual moult events. The larval duration can be protracted and may last anywhere between months to years, dependent on a number of factors including the species, availability of feed and environmental conditions.

At the completion of the phyllosoma phase of development spiny lobsters undergo an extreme metamorphosis event, transforming from a two-dimensional clear disc shaped phyllosoma into a three-dimensional shaped puerulus.

This puerulus is a non-feeding nektonic stage; the primary purpose of this life-phase is to swim from the offshore waters to inshore reef systems or other suitable benthic habitats to settle upon. This migration from oceanic waters to reef habitats during the puerulus phase is often a distance of hundreds of kilometres.

When they have reached a suitable habitat puerulus will undergo a final larval moult transforming into the benthic juvenile phase and assume typical lobster morphology. Currently, aquaculture farmers will target both of these latter stages of development to enable the stocking of their sea cages.

Puerulus are caught at night in inshore bays using lights for attraction into fine mesh nets, or alternatively harvested from artificial settlement structures, such as bundles of mesh or used cement bags.

The juvenile development phase is also targeted using poles with small holes drilled in them set near the shoreline; this structure provides a habitat for juvenile lobsters to shelter in and thus a means of collection for farmers. The preferred culture species targeted in Vietnam is Panulirus ornatus, also known as the tropical, ornate or painted lobster, however obtaining this species from local waters can be difficult, with other less commercially desirable species also being collected and cultured.

There are a number of issues with the reliance on collection of seed stock from the wild, including sustainability, reliability of supply, biosecurity and the inability to obtain genetic improvement of cultured stocks.

The long and complex lifecycle of spiny lobsters has provided challenges for the establishment of a sustainable commercial aquaculture industry. The collaboration between expert scientists and industry in the ARC Research Hub for Commercial Development of Spiny Lobster Culture Systems has provided the platform for innovative research to bring the dream of sustainable farming of lobsters a step closer.

Read the full article, HERE.

The Aquaculturists
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