Cold-water fish fac­ing threats

Eco-warm­ing called per­va­sive threat to key fish in north­ern On­tario

Kingston Whig-Standard - - WORLD NEWS - COLIN PERKEL

TORONTO — Grad­ual warm­ing due to cli­mate change posts the most per­va­sive threat to a vi­tal eco­nomic and cul­tural re­source in one of the world’s last in­tact ecosys­tems: The fish that live in the icy wa­ters of north­ern On­tario, new con­ser­va­tion re­search sug­gests.

In a re­cent re­port on their find­ings, re­searchers found warmer wa­ters would make species such as brook trout, wall­eye, lake white­fish, and lake stur­geon more vul­ner­a­ble to other threats such as habi­tat loss and frag­men­ta­tion of wa­ter­sheds and streams.

“As in many other places, the fresh­wa­ter habi­tats of north­ern On­tario face a va­ri­ety of threats, both nat­u­ral and as a re­sult of hu­man ac­tiv­i­ties,” ac­cord­ing to the study from Wildlife Con­ser­va­tion So­ci­ety Canada. “The largest sin­gle threat is cli­mate change, which is oc­cur­ring more rapidly in the north com­pared to the rest of On­tario.”

On­tario’s Far North con­tains some of the world’s largest un­dammed rivers. It is home to thou­sands of lakes and the largest wet­land com­plex in North Amer­ica. Its fresh­wa­ter ecosys­tems sup­port at least 50 species of fish, mak­ing it the largest area of high fish bio­di­ver­sity in Canada, ac­cord­ing to the re­port.

At the same time, its re­mote­ness and sparse pop­u­la­tion — although home to about 40 Indige­nous com­mu­ni­ties — has made it un­der­stud­ied even as the provin­cial gov­ern­ment at­tempts to fos­ter de­vel­op­ment, par­tic­u­larly in the min­eral-rich area known as the Ring of Fire.

In an ef­fort to fill in some of the knowl­edge gaps, the study is based on com­puter-as­sisted pro­jec­tions of what would hap­pen to fish pop­u­la­tions over the next 50 years in a re­gion cov­er­ing about 440,000 square kilo­me­tres based on high and low-de­vel­op­ment sce­nar­ios — ad­mit­tedly “rough” mod­els that nev­er­the­less per­form “re­mark­ably well,” the re­searchers say.

“This is re­ally ground-break­ing work in many ways, both in its fo­cus on cul­tur­ally im­por­tant fish ... and the de­vel­op­ment of new mod­el­ling ap­proaches with fish­eries ex­perts from across North Amer­ica,” said Ch­eryl Chetkiewicz, a con­ser­va­tion sci­en­tist and one of the re­searchers.

A huge prob­lem, the re­port con­cludes, is the short-term piece­meal ap­proach to plan­ning that fails to take into ac­count the cu­mu­la­tive im­pacts of en­vi­ron­men­tal stres­sors due to de­vel­op­ment when com­bined with cli­mate change. Con­tin­u­ing down this path, Chetkiewicz said, could have “dev­as­tat­ing con­se­quences” for both fish and peo­ple in the re­gion.

Ac­cord­ing to the study, cli­mate change will ex­ac­er­bate po­ten­tial prob­lems caused by fish­ing, in­dus­trial forestry, min­ing and min­eral ex­plo­ration, hy­dro­elec­tric de­vel­op­ment, and new in­fra­struc­ture such as roads and trans­mis­sion lines.

Study mod­el­ling pre­dicts sub­stan­tial warm­ing in the Far North over the next 50 years — put­ting wall­eye, lake stur­geon, lake white­fish, and brook trout at risk.

“All four species ex­hib­ited in­creased risk over the sim­u­la­tion pe­riod,” the study finds.

“Over­all, cli­mate change was the most in­flu­en­tial driver of risk to fresh­wa­ter fish, fol­lowed by hy­dro­elec­tric dams. Cli­mate change con­sis­tently ex­ac­er­bated the ef­fects of land use and nat­u­ral dis­tur­bance changes.”

The study makes sev­eral rec­om­men­da­tions aimed at mit­i­gat­ing neg­a­tive im­pacts on the fish with­out shut­ting down de­vel­op­ment in the re­gion.

Key among them is to as­sess those im­pacts over time and in com­bi­na­tion — based on solid em­pir­i­cal data.

“While we can­not be ab­so­lutely cer­tain about fu­ture con­di­tions, we can ex­am­ine plau­si­ble sce­nar­ios based on cur­rent in­for­ma­tion and in­formed as­sump­tions,” the study states.

“This al­lows po­ten­tial en­vi­ron­men­tal im­pacts to be un­der­stood and eval­u­ated to­day with a fo­cus on risk man­age­ment — be­fore op­tions for land-use man­age­ment and con­ser­va­tion have been fore­closed.”

Other rec­om­men­da­tions in­clude pri­or­i­tiz­ing ar­eas for fresh­wa­ter fish re­search and pro­tec­tion, and the need for a re­gional and strate­gic ap­proach to as­sess­ing the im­pact of hy­dro­elec­tric de­vel­op­ment.

POST­MEDIA NET­WORK FILES

New con­ser­va­tion re­search sug­gests warmer wa­ters would make species such as brook trout, above, wall­eye, lake white­fish and lake stur­geon more vul­ner­a­ble to other threats such as habi­tat loss and frag­men­ta­tion of wa­ter­sheds and streams.

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