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Scallop Research Generates Micro-algae Test

03 March 2014

FRANCE - French fishermen land between 25,000 and 30,000 tonnes of scallops in a six-month autumn and winter campaign. While this catch is worth €40 million at the quayside, wholesale prices the Paris wholesale market Rungis have remained stable for the past 10 years. This means that prices for this splendid shellfish are comparable to whelks, writes Peter Crosskey.

There are 250 Breton and 200 Normandy boats specialising in this catch. The opening weeks of the French season in October and November are often a scramble for scallops that take a bite out of quotas but do not fetch the higher prices commanded by December landings.

In a bid to find solutions for some of the problems faced by scallop fisheries on the French side of the Channel, the three-year COMANCHE project has brought together researchers from the national oceanographic institute IFREMER, research agency CNRS, universities in the ports of Brest and Caen, as well as Paris, in a multi-disciplinary study.

The team will present more of its conclusions later this year.

Many of the findings will be specific to scallop fisheries, but there is a promising development in testing to detect human-toxic microalgae, which can make catches a health hazard and unsaleable.

“Phytochip recognises genetic markers that are specific to toxic microalgae,” Ifremer researcher Dr Catherine Dreanno told TheFishSite.

“The test has been developed for laboratory use and does not require users to distinguish or recognise specific features of the organism.”

In the case of scallops, during some years fishing has been closed by toxic episodes involving domoic acid produced by certain Pseudo-nitzchia algae, which scallops eat.

Of the 30 known Pseudo-nitzchia, some but not all produce a toxic bloom: “It is important to be able to distinguish them,” Dreanno explains, “so as to know if a potentially toxic algae is present or not.”

Until now, testing involved lengthy examinations by an expert with detailed knowledge of the organisms’ morphologies.

That is why Dreanno has been working on this specific implementation of biochips alongside an INSA team led by Dr Véronique Le Berre in Toulouse.

In simple terms, the chip works like a barcode reader for genetic material, for which the Toulouse team has created the architecture and Dreanno identified the genetic signposting for Pseudo-nitzchia.

For a number of reasons Phytochip cannot be relied on for toxin concentrations at present.

“Knowing whether or not the majority of species present in the sample are toxic is important, since it can trigger a subsequent toxin analysis more rapidly,” Dreanno adds. In addition, this preliminary test will allow a cost-effective testing régime to cover more sites, more often.

Future applications of Phytochip will be adapted to other specific food industry needs. The Toulouse team, for instance, is already working on a version to detect bacteria such as Listeria.


TheFishSite News Desk

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