An Irish marine scientist working in Australia has learned how to turn white speckled lobsters red, writes JEREMY O'BRIEN
WHY HAS Irishman Adrian Linnane spent the last three years turning 5,000 of South Australia’s rock lobsters from speckled white to red? Because Chinese consumers prefer them that way.
The work was part of a research project aimed at opening up an export market to China worth around €50 million to Australian producers.
Perhaps more interesting is how he’s done it. He has taken Australian Southern Rock Lobsters (Jasus edwardsii) from their offshore homes around 100m below the waves and brought them closer to shore where depths are less than 20m. Linnane has shown that when in shallower water the lobsters’ shells change from speckled white to red, the colour so prized by the Chinese.
“Red is a sign of prosperity and good luck for the Chinese,” explains Linnane, the senior rock lobster scientist for the South Australian Research and Development Institute, who won Fisheries Research and Development Corporation funding. “Because of these market demands, processors are able fetch 5-10 Australian dollars (€2.50-€5) more per kg for red lobsters, even though it’s the exact same animal. We only tend to find these lobsters inshore.”
This means the fisherman takes most of the catch near shore. “It’s not rocket science: he’s going to focus his efforts on the more valuable animals.”
The question was could moving less valuable speckled lobsters from their offshore homes to join their brothers and sisters nearer the surface change their colour?
So in 2007 and 2008 Linnane and his team caught 5,000 white speckled lobsters in the deep offshore waters. They photographed, tagged and measured all 5,000, and then deposited them in shallower waters nearer to shore.
There was cause for optimism: scientific wisdom held that the difference in shell colours was down to the diets of the rock lobsters in the two different locations. The red algae found in shallower water, or other critters that eat red algae, were the likely dishes being eaten by the shallow water lobsters, but not their deep water brothers and sisters.
However, it is hard to tell what a lobster eats because they don’t produce faeces, explains Linnane. “They are ferocious in terms of how they break things down. They have a gastric mill in their intestine which result only in the excretion of urine.”
Another worry was would the lobsters stay put in their new home? “We had done major tagging studies before that showed that these lobsters don’t make the long hundreds of thousands of kilometre journeys that other species do.” This gave the team hope that the lobsters wouldn’t simply turn around and head for their deep sea home. And they didn’t – no tagged lobsters were caught offshore (although fishing there was moderate).
Linnane relied on a good relationship with the lobster industry to collect the data. After one year 400-500 of the tagged lobsters had been caught, and every one had changed to the prized red colour.
A key to this success is that lobsters moult, replacing their shell each year, explains Linnane. “The shell splits in half and they reverse back out of their old shell, and then eat it because they need the calcium.”
What Linnane’s research has shown is that just one moulting is enough for 100 per cent of the recovered lobsters to have changed colour. A year in their new environment, with a new diet, was all it took.
In addition to the obvious commercial advantages, Linnane’s work has captured the imagination of the local community. “It’s something that people can relate to and has got people here interested in lobster science. It is also an example of industry and science working together – we give them useful information, and they document and return the tagged lobsters.”
So what’s next? Linnane says it’s up to the industry now to determine whether a large scale approach is economically viable. There are substantial costs associated with bait and fuel that make fishing twice for the same lobsters much more expensive.
So how did Linnane come to be working on the reefs of South Australia? After completing a marine science degree in Aberdeen, a PhD at NUI Galway, looking at lobster stock enhancement in Carna, Co Galway, and several EU-funded post-doctoral appointments in Ireland, he was certainly well qualified.
After being awarded a prestigious Enterprise Ireland post-doctoral research fellowship in 2001 to spend six months at the Royal Melbourne Institute of Technology, he spent six months travelling around Australia and really liked it. “I thought to myself, if a job ever came up in Australia I’d apply.” Four months after returning to Ireland one did, and Linnane has been there ever since.
Jeremy O'Brien is based at the University of Bristol and is on placement at The Irish Timesas a British Science Association Media Fellow