Vince McDonagh

They know their plaice

Could this be the next species for commercial farming?

BY VINCE MCDONAGH

TRIALS aimed at breeding plaice under farming condi� ons have proved highly successful, less than two years a� er ge� ng underway. The results have even surprised the scien� sts at Norway’s Ins� tute of Marine Research (IMR), which is conduc� ng the experiment.

Plaice may not be quite as fashionable as it was, say, in the 1970s (in the days before farmed salmon became plen� ful), but it remains a popular whitefi sh choice among diners.

This is a fi sh that can live for up to 50 years. However, they are slow growers, which means wild stocks are under increasing pressure. So around two years ago the IMR decided it was to � me to see if they could breed successfully in cap� vity.

It may surprise some people to learn that the fi rst serious a� empt at plaice farming was carried out in 1945, just a� er the end of the Second World War. Fry produc� on was the main goal at the � me and the researchers managed to breed several thousand of them using live shrimp as feed.

It was seen as a major breakthrough, although – un� l today – nothing much more was done a� er the 1940s. Back then there was an abundant supply from the sea so it failed to a� ract much interest from poten� al backers.

Just over a year ago Fish Farmer magazine reported that trials into plaice farming had resumed, picking up where the 1940s researchers had le� off .

Now the 21st century IMR team has just announced that their trials have produced very young fi sh with no disease, few deformi� es and virtually no serious mortality problems. 36

Using past experience with halibut farming – one of the most diffi cult species to cul� vate – as a basis for the research, they seem to have created the perfect fry.

IMR researcher Anders Magnor-Jensen says the results have been “absolutely fantas� c”. He adds: “Now we are le� with two family research groups that can give us a brood-stock for the future.”

Magnor-Jensen is now following up the work on larger fi sh. As he explains: “Biologically, the experiment did present

us with a few challenges at the beginning, but we believe plaice may have the poten� al to become a new (farmed) marine species.”

He said results from data base were not yet clear, but growth was comparable to that of halibut during the fi rst 10 to 12 months. However, it seems that plaice grows faster than halibut in the fry stage.

Birgi� a Norberg, another member of the research team, said at the � me of the earlier trials that, thanks in part to previous research, companies are now adding or considering including halibut farming to their commercial opera� ons.

The long-term hope at the Ins� tute is that if results from the current research programme con� nue to be successful – and the team seems very confi dent – then plaice will be added to the list of commercially farmed species.

It seems that � me cannot come soon enough. Earlier this year Norway, the UK and the EU agreed a new fi sheries deal in the North Sea, the main loca� on for the species, which brought a 25% reduc� on in the plaice quota. Plaice is also found in the Irish Sea and around the coasts of Norway and Iceland.

Mangor-Jensen explained: “We have managed to breed plaice with zero diseases, no mortality and minimal deforma� ons. Fish that survive and grow as well as this means their welfare is good.”

He said that although wild plaice can o� en reach four or fi ve kilos, they are very heavily fi shed so are o� en very small when caught and are usually lucky to reach half a kilo. The hope is that the farmed plaice will be so large they can produce fi llets two or three cen� metres thick (around one inch).

The next stage now is to fi nd out if this type of fl ounder fi sh can grow to a commercial size of around a kilo (2.2lbs) before they are three years old.

With an established market and proven success in raising the fi sh in cap� vity, this could prove to be a very interes� ng species for farmers.” FF

“They seem to have created the perfect fry”

Above left: Researcher Anders Magnor-Jensen Top: Young plaice growing up Left and above: Plaice

A WORLD-LEADING RESEARCH GROUP

BASED in Bergen, the Ins� tute of Marine Research (IMR) is one of the leading Research (IMR) is one of the leading organisa� ons of its kind in Europe, with organisa� ons of its kind in Europe, with several hundred employees. Its ac� vi� es are several hundred employees. Its ac� vi� es are research, advisory work and monitoring. research, advisory work and monitoring.

It has its own research vessels and laboratories that look at the whole seafood laboratories that look at the whole seafood food chain from the sea or net cage to food chain from the sea or net cage to the table. Most of its funding comes from the table. Most of its funding comes from various government departments and various government departments and external grants. external grants.

Although the IMR advises the Norwegian government on the ecosystems of the government on the ecosystems of the Barents Sea, Norway’s most important Barents Sea, Norway’s most important fi shing area, the rapid growth in fi sh farming fi shing area, the rapid growth in fi sh farming of all types means that more of its work is of all types means that more of its work is now focused on aquaculture. now focused on aquaculture.

Above: The Ins� tute of Marine Research in Bergen

Plaice facts

La� n name: Pleuronectes platessa, derived from the Anglo-French word plai which means fl a� ish Family: The fl ounder family (Pleuronec� dae) Other names: Flounder, fl a� ish Max size: 70cm across