Fishermen help to find where disappearing lobsters hide

LOBSTER fishermen working the inlets of south west Connemara in currachs are at the cutting edge of marine science. They have been enlisted to help international scientists in solving a mystery about the lobster's life cycle.

Resolving the mystery could help arrest a decline in lobster stocks in Ireland and Europe. Many small communities, particularly along the coast from Donegal to Cork, will in turn be rewarded with growing returns from a high value shellfish product. In coastal areas, people have been asked to play their part in the detective work.

A considerable amount of knowledge exists about lobsters reared from larvae to commercial size in laboratories - notably, in the Irish context, at UCG's Shellfish Laboratory in Carna, Connemara - but much of their development in the ocean is still a mystery.

At their tiny larval stage they can be easily found swimming the seas, but once they settle in the seabed, they disappear for several years; their hiding place unknown. Filling in this gap in their biology could be the key to their maximising the crop and yet ensuring their survival in plentiful numbers.

Dr John Mercer, director of the shellfish laboratory, is co ordinating an EU funded project to try to find the answers over the next three years. The LEAR (lobster ecology and recruitment) project involves scientists from Italy, Norway and Britain as well as Ireland, who gathered in the past few weeks in Galway to start the research.

First stop was Galway Bay and excursions aboard the UCG research vessel, Conamam, from where they linked with the fishermen. They led them to traditionally rich areas for mature lobsters. It is believed that the "early benthic juveniles", to give them their official description, embed themselves in the sea floor in such areas or close by.

It is somehow gratifying to think that fishermen, whose art has not changed to any significant degree in many generations, have a pivotal role in research conducted by scientists and backed up by the most sophisticated technology available.

Essentially, two types of lobster are found around Ireland. Both are edible; the clawed lobster (both the familiar dark blue one and the Dublin Bay prawn) and the spiny lobster or crawfish. The two types have discernible but different behavioural differences.

Clawed lobsters - the subject of the LEAR study - are aggressive and even cannibalistic while spiny lobsters, though larger, are "gregarious, matriarchal animals", according to Dr Mercer. In fact, they are known to converse noisily by rubbing together serrated pads at the base of their antennae.

The team set about establishing agreed sampling procedures with minimal impact on the seabed, before returning to their own countries to investigate their respective lobster fisheries. The focus is on what's known as the sixth stage in the life cycle, when the tiny creature has shed its shell or carapace six times before it disappears. At that point, it is barely the size of a match stick and has a shape like a scorpion.

The clawed lobster, Homarus gammarus, is an important economic resource. It trades at about £12 per kilo and is worth over £6 million a year on the domestic market, more if exports are factored in. The total haul is about 700 tonnes. Add in business from the sale of crayfish and shrimp along a huge stretch of coastline stretching from the south coast to Connemara and it amounts to a vital part of the rural/coastal economy in many locations, according to Ronan Browne of Carna Shellfish Laboratory.

He is working on LEAR and with the Udaras na Gaeltacta supported company, Taighde Mara, which is producing juvenile clawed lobsters in the lab for release into over fished areas. "This is working very well. We hope to see a significant increase at sea within four to five years. But it is very important to know the exact nature of the habitat they're living in there for release purposes."

Strangely enough, in the US it is possible to trace lobsters at all stages of their life cycle. In Europe, their niche at juvenile stage has yet to be found. So Dr Mercer and his team have circulated fishing communities and coastal combers to be on the look out for lobsters of less than the standard size of a box of matches. Information, it is hoped, will flow to the UCG Shellfish Laboratory.

They have been asked to note details of their finds including size, depth where they are found and a description of the seabed conditions - lobsters with a carapace, the hard shell over the back, of less than three inches cannot be taken from the water and if caught must be returned to the water.

"Your knowledge of the area you find them in could be of vital importance to this project and the future of lobster stock enhancement work," reads the message. After all, team work can make for good science.