‘Frag­ile and vul­ner­a­ble’

Cli­mate change takes toll on French oys­ter farm­ers

Global Times - Weekend - - FRONT PAGE -

Gulp­ing down oys­ters has long been a fa­vorite New Year’s Eve rit­ual for the French, but as win­ters get warmer and sum­mers get drier many grow­ers worry there will soon be fewer of the prized mol­lusks to go around.

“Twenty years ago, we’d be shiv­er­ing in the ware­house while pre­par­ing the hol­i­day or­ders. To­day it’s 15 de­grees [C],” said Brit­tany oys­ter­man Mathieu Le Moal, his sleeves rolled up in front of a trac­tor car­ry­ing dozens of bulging oys­ter sacks.

“We don’t have sea­sons any­more – but oys­ters need all four,” Le Moal added. “They need the win­ter, it’s when they can rest, use less en­ergy.”

In­side a wooden hanger redo­lent of salt and the sea, around a dozen of his work­ers are sort­ing, weigh­ing and pack­ing oys­ters into crates in the Brit­tany port of Can­cale.

Le Moal and other farm­ers along this stretch of France’s Emer­ald Coast say the long drought which struck swathes of the coun­try this sum­mer took a heavy toll, lead­ing to smaller har­vests, and smaller shell­fish.

With­out sum­mer rains that wash cru­cial min­er­als into the oys­ter beds, “there’s no plank­ton, the main food for oys­ters, so they don’t grow,” ex­plained fel­low oys­ter­man Bertrand Racinne, weav­ing his way be­tween bas­kets and stacked crates.

“In the end, we have oys­ters but not enough of the big ones,” said Racinne, who like most grow­ers sells more than half his yearly pro­duc­tion in De­cem­ber.

Cold weather nor­mally en­cour­ages a needed rest for oys­ters to ma­ture, said Yoann Thomas of France’s IRD re­search in­sti­tute.

But this win­ter has so far been un­usu­ally warm and, para­dox­i­cally, too rainy.

Rains may bring min­er­als that fa­vor plank­ton growth – but they also mean the mol­lusks spend too much en­ergy eat­ing.

This year’s har­vest are likely to start the spring “frag­ile and vul­ner­a­ble,” warned Racinne.

“We’ve found that pe­ri­ods of ex­treme mor­tal­ity [more than 25 per­cent of oys­ters] come sev­eral months af­ter mild and rainy win­ters,” Thomas said.

Germs thrive

“Ten grams fewer for each one, that makes a dif­fer­ence in sales,” said Philippe Le Gal, pres­i­dent of the CNC na­tional shell­fish pro­duc­ers’ as­so­ci­a­tion.

In 2017, the roughly 4,500 oys­ter grow­ers in France sold 100,000 tons, at an av­er­age price of 5,000 eu­ros ($5,700) per ton.

“Oys­ter farm­ers will see vol­umes down by 20 to 30 per­cent this year,” Le Gal said. “Cli­mate warm­ing is start­ing to have an im­pact.”

Warmer wa­ter tem­per­a­tures are also a risk be­cause they fa­cil­i­tate the spread of viruses that are es­pe­cially harm­ful to oys­ter lar­vae, or spat, and young oys­ters.

Sci­en­tists point in par­tic­u­lar to a Her­pes virus, OsHV-1, that has been present in French oys­ter wa­ters since 1991 but has be­come more ag­gres­sive re­cently, for rea­sons still un­known.

Since 2008, up to 75 per­cent of young oys­ters have been lost in some years, said Fab­rice Per­net at the Ifre­mer ocean re­search in­sti­tute in Brest.

“Oys­ter farm­ers had found a so­lu­tion by putting 10 times the amount of spat in the wa­ter in au­tumn, when the virus is not ac­tive,” Per­net said.

But warmer wa­ters would re­duce this win­dow of op­por­tu­nity, he said, and new pathogens could ar­rive if car­ried north by fish and other sea life flee­ing ris­ing tem­per­a­tures fur­ther south.

Adding to the chal­lenges, ris­ing ocean acid­ity re­quires oys­ters to spend more en­ergy in build­ing their shells, Per­net said.

‘Still mag­nif­i­cent’

Er­ratic and ex­treme weather con­di­tions are likely to be­come more fre­quent un­less ag­gres­sive steps are taken to limit cli­mate change caused by hu­man ac­tiv­i­ties, sci­en­tists warn.

“By 2035 the ab­nor­mally high mor­tal­ity episodes that cur­rently oc­cur ev­ery 10 years risk hap­pen­ing ev­ery two years,” Per­net said.

Not ev­ery oys­ter farmer is con­vinced, how­ever, say­ing the big­ger risks are pol­lu­tion, oys­ter beds that are be­com­ing too densely packed and the in­creased use of ge­net­i­cally mod­i­fied species.

“Mor­tal­ity rates change ev­ery year, de­pend­ing on the re­gion... but no­body can re­ally ex­plain why,” said Alexan­dre Prod’homme, an­other grower in Can­cale.

But if warm­ing and weather pat­terns be­come in­creas­ingly volatile, French farm­ers might have to start chang­ing their grow­ing sea­sons or move their beds north or fur­ther out to sea, Per­net said.

“Oys­ters aren’t go­ing to dis­ap­pear... but they’re prob­a­bly go­ing to have to mi­grate,” he pre­dicted.

For now, most grow­ers say they’re go­ing to wait and see.

“We’re not sure about any­thing re­gard­ing the im­pact of global warm­ing, we’re wait­ing for more sci­en­tific re­search,” said Daniel Coirier, pres­i­dent of the shell­fish as­so­ci­a­tion for the Poitou-Char­entes re­gion.

“But even if they’re not as big, our oys­ters are still mag­nif­i­cent, and top qual­ity!”

French oys­ters

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