It’s a tricky task turning larvae into rock lobsters
CHINESE diners in 2017 tucking into a succulent Tasmanian rock lobster may have Arthur Ritar to thank for the treat.
It is a distant scenario in more ways than one, but that is the way with long- range research. Ritar, a senior research fellow and leader of the University of Tasmania’s rock lobster aquaculture group, is working on getting the lobsters from the egg, through a difficult larval stage and out the other end where they start looking like lobsters.
The larval stage, at six to 12 months, is much longer than any other aquaculture species. In the wild it is as long as two years.
The lobsters grow from a 1mm egg into 2mm larvae, ending as 40mm juveniles before they undergo a metamorphosis in which they ‘‘ become obviously lobsters’’.
‘‘ Until then they are a strange shape, like a flat spider,’’ Ritar says. ‘‘ We’re trying to define the conditions that are best to get them through the metamorphosis and not die in large numbers. We’re trying to develop culture systems where we can produce large numbers of juveniles in a hatchery. The obvious problem with lots of animals in one small volume is disease.’’
Ritar describes the larval stage as a bottleneck. Without giving away too many trade secrets, he says he is working on developing the technology to improve water quality, minimise disease and improve the nutrition for developing larvae. ‘‘ All our efforts are focused on this time,’’ he says.
A commercial fishery could be up to 10 years away. ‘‘ We work on a long time frame and the people interested realise there’s a long time scale,’’ Ritar says.
Very little is known about the lobsters’ development in the wild except that they disperse and go through metamorphosis, then swim back to shore and settle on rocky reefs.
There is no Australian cultured rock lobster industry but Ritar says there is potentially a good market for it.
‘‘ The size of the fishery is limited and the demand for lobsters is increasing worldwide,’’ he says.
Vietnam’s cultured lobster industry produces about 2000 tonnes a year but growing caught juveniles from 0.5g to 1kg is a boomor- bust proposition that depends on natural breeding fluctuations.
The approach at the university’s Tasmanian Aquaculture and Fisheries Institute is to go for the eggs.
‘‘ One breeding female can lay more than 100,000 eggs and you don’t need many to supply a hatchery,’’ Ritar says.
The likeliest business model is hatcheries for rearing larvae to juvenile stage for sale to farmers, who then grow them to a marketable size for selling them to the big tables in China.
Culture warrior: Arthur Ritar and a friend