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Almost no more seafood after 2048 at current rates, study warns

Nov. 2, 2006
Special to World Science  

Sea­food will be all but a memory by 2048 if bulging hu­man pop­u­la­tions keep de­vour­ing fish and pol­lut­ing oceans at cur­rent rates, warns a study pub­lished in the Nov. 3 is­sue of the re­search jour­nal Sci­ence.

There will be few sea­food fish left four decades from now if cur­rent trends keep up, a study sug­gests. (Im­age cour­te­sy NOAA)
“Species have been dis­ap­pear­ing” fas­t­er and fas­t­er, said lead au­thor Bo­ris Worm of Dal­hou­sie Uni­ver­si­ty in Ha­l­i­fax, Can­a­da. “If the long-term trend con­tin­ues, all fish and sea­food spe­cies are pro­jected to col­lapse with­in my life­time.”

“Col­lapse” is de­fined as the catch of a spe­cies drop­ping by 90 per­cent, said Worm, one of a group of eco­l­o­gists and eco­n­o­m­ists stu­dy­ing how ma­rine bio­di­ver­si­ty helps sus­tain hu­manity.

“Worm and col­leagues have pro­vid­ed the first com­pre­hen­sive as­sess­ment of the state of ec­o­sys­tem ser­vic­es pro­vid­ed by the bio­di­ver­sity of the world’s oceans to hu­manity,” said Sci­ence in­ter­na­tion­al man­ag­ing ed­i­tor An­drew Sug­den.

The study is based on a wide ar­ray of his­tor­i­cal and ex­per­i­men­t da­ta, he added.

Twen­ty-nine per­cent of fish and sea­food spe­cies have col­lapsed al­read­y, Worm said. “It is a very clear trend, and it is ac­cel­er­at­ing. We don’t have to use mod­els to un­der­stand this trend; it is based on all the avail­a­ble da­ta.”

The prob­lem is much great­er than los­ing a key source of food, he added. Dam­age to oceans af­fects not on­ly fish­er­ies, but the ocean ec­o­sys­tem’s over­all pro­duc­tiv­i­ty and sta­bil­i­ty, he said. A dwindling va­ri­e­ty of spe­cies have a harder time main­tain­ing wa­ter qual­i­ty through bi­o­log­i­cal fil­ter­ing, pro­tect­ing shore­lines, con­t­rol­ling harm­ful al­gal growths and pre­serv­ing ox­y­gen lev­els.

“The good news is that it is not too late to turn things around,” Worm said. The sci­en­tists stud­ied 48 ar­eas world­wide that have been pro­tected to im­prove ma­rine bio­di­ver­sity. “We see that di­ver­si­ty of spe­cies re­cov­ered dra­mat­i­cal­ly, and with it the ec­o­sys­tem’s pro­duc­tiv­i­ty and sta­bil­i­ty.”

“We hard­ly ap­pre­ci­ate liv­ing on a blue plan­et,” Worm said. “The oceans de­fine our plan­et, and their fate may to a large ex­tent de­ter­mine our fate.”

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There will be almost no seafood left by 2048 if bulging human populations keep devouring fish and polluting oceans at current rates, predicts a study published in the Nov. 3 issue of the research journal Science. “Species have been disappearing” faster and faster, said lead author Boris Worm of Dalhousie University in Halifax, Canada. “If the long-term trend continues, all fish and seafood species are projected to collapse within my lifetime.” “Collapse” is defined as the catch of a species dropping by 90%, said Worm, who formed part of a team of ecologists and economists studying marine biodiversity’s role in sustaining humanity. “Worm and colleagues have provided the first comprehensive assessment of the state of ecosystem services provided by the biodiversity of the world’s oceans to humanity,” said Science International Managing Editor Andrew Sugden. The study was based on a wide array of historical and experimental data, he added. Twenty-nine percent of fish and seafood species have collapsed already, Worm said. “It is a very clear trend, and it is accelerating. We don’t have to use models to understand this trend; it is based on all the available data.” The problem is much greater than losing a key source of food, he added. Damage to oceans affect not only fisheries, but the ocean ecosystem’s overall productivity and stability, he said. A dwindling variety of species have a harder time maintaining water quality through biological filtering, protecting shorelines, staving off harmful algal growths and preserving oxygen levels. “The good news is that it is not too late to turn things around,” Worm said. The scientists studied 48 areas worldwide that have been protected to improve marine biodiversity. “We see that diversity of species recovered dramatically, and with it the ecosystem’s productivity and stability.” “We hardly appreciate living on a blue planet,” Worm said. “The oceans define our planet, and their fate may to a large extent determine our fate.”