In prehistoric times, laketroutchanged. Theysurvivediceages by movingsouth. Theyinterbred, returnednorthwhen glaciers retreated, and leftagainwhen glaciers returned. As a result of theirinterbreeding, laketrout in Ontario are a speciesthat dates back only 11,000 years, to the end of the last Ice Age.
However, there’s one place in the Haliburton Highlands where the laketrout date back hundreds of thousands of years, throughseveraliceages. Somehow, no one knowshow, theybecameisolated, survived the iceages, and duringthat time neverinterbred.
They’refoundonly in threelakes: Macdonald, Clean, and Black Lakes, just to the west of the lower tip of Algonquin Park.
They are underassaultfrominvadingspecies, but for the moment, they’rehanging on thanks to the efforts of Peter Schleifenbaum, whosecompany Haliburton Forest and Wild Life Reserve owns the land around the lakes, and the Ontario Ministry of Natural Resources (MNR) whichowns the lake water bodies.
As John Casselman, the MNR researchscientistwho first identified the trout, explains, the lakes are deep and cold at the bottom. The trouthaven’tleftbecausetheirfoodsupply has been adequate, and they are cold water fishthat have avoidedwarmer surface waters that lead to connectingrivers.
However, theirfoodsupply has been underattack by rock bass, an invadingspecies, thatwasintroduced to the lakes about 18 yearsago — shortlybeforeSchleifenbaumarrived in Canada from Germany to take over management of the 25,000 hectare Haliburton reservethathad been passed down fromhisfather.
No one knowshow the bassgotinto the lakes, but theyfed on laketroutfry, and competed for shiners, crayfish, and otherbaitfishthat the trouteat. The bass are voracious, and because of theirspiky dorsal fins, the troutleftthemalone. So the bassflourished and the trout have languished, growingsmaller in size and not breeding as prolifically as theyhad.
In the early 1990s, Schleifenbaumwas in the beginning stages of turning the reserveinto an ecotourism destination. In that, he has been successful. The reservenow has an annual operating budget of $5 million to $6 million and, for a fee, offersvisits to a wolf pack enclosure, a « walk in the clouds’’ 20 metresaboveground in white pines, dog sledding, camping, hunting and fishing, snowmobiling, mountainbiking, birdwatching, and a star-gazingobservatory.
Schleifenbaumwanted to protect the ancienttrout not only as an attraction, but becauseit fit hisphilosophy of stewardship. « In title, I own the land,’’ hesays. « But, in reality, youcan’townit; you are simplyits steward.’’
Good stewards « protect all (life forms) in perpetuity. Why? Because I believethat the original ecosystems are the most stable.’’ And stability, headds, is important in facing the threat of disruptive change, whetherbrought on by invadingspecies or from global warming. In addition, heconcludes, « stable ecosystems are also the mosteconomicallysound and profitable.’’
In implementinghis concept of stewardship, he has amassed a databank of information thatisgoing to beinvaluable.
Environmental inventories have been completed on 300 marshes. Fishers are required to file reports on whattheycaught and the conditions theyencountered. Reserve staff inspect and record what hunters have brought down. Staff are instructed to collectanywolf scat theyfind, and itislateranalyzed. Regular bearsurveys are conducted, as are surveys of smallmammalssuch as mice and lemmings. Examination of treecanopies have revealedpreviouslyunidentifiedinsects. And last year, an inventory of bats wascompleted.
Schleifenbaumthoughthemightbe able to solve the rock bassproblem by establishing a summer-long fishing derby for childrenwithprizes for the mostbasscaught. The derby was a greatsuccess, with 14,000 basscaught in the derby’s first threeyears. But itfailed to control the rock bass. Casselmandiscoveredthat the biomass of rock basshadn’t change at all. The onlydifferencewasthattherewerefewerbig rock bass, and a lot more smallones.
To betterprotect the ancienttrout, Schleifenbaumaskedfishers to release anythatwere longer than 15 inchesbecausethey are the breedingadults. And twoyearsago, the MNR bannedfishingduring July and August because of a concernthat the shock of beingdraggedfromdeep, cold water to warm surface water wouldkillthem, even if theywerereleased. In addition, the MNR imposed a catch limit of one fish per person, per day, during times whenfishingisallowed.
The nextthreat to the troutislikely to befromspiny water fleas, anotherinvadingspeciesthat has reachedneighbouringKennisis Lake. Like rock bass, thereis no knownway to control them. Theyeatsmallerplankton, and althoughtroutcanfeed on them, theyprovidelittlenourishmentbecausesomuch of their bodies are spines. In the meantime, the fleasreduce the amount of planktonavailable to trout, as well as the number of baitfish, becausetheyalsofeed on the diminishingsupply of plankton.
In the final analysis, the onlydefencetheseancienttrout have against the rock bass, and the potentialthreat of spiny water fleas, remainsSchleifenbaum’sdetermination to maintain original ecosystems in the reserve.
Whathe’sdoingisprotectingresilience, in the hopethat the ecosystemwillrespondwithitsownmethod of control. As always, nature’s best defenceisdiversity. But willitbeenoughagainsttheseinvaders? I wish I knew.