Coastal Cutthroat Trout as Sentinels of Lower Mainland Watershed ...

66because piscivorous Taylor Lake cutthroat likely use small rainbow as a food source,providing an opportunity for trophy-sized cutthroat in the catch. Consideration should begiven to maximum size regulations on cutthroat in these rainbow-cutthroat lakes thatwould encourage the development of large piscivorous cutthroat, thus making these lakefisheries more attractive to anglers. Hybridization of rainbow with cutthroat trout inthese lakes can have genetic consequences from a loss of fitness of native cutthroat, andthus further rainbow trout stocking of native cutthroat lakes should be largely avoided (E.Parkinson, pers. comm. 2004).A concern raised by Lister (1999) at Hicks, Deer and Weaver Lakes, and noted byGeorge (1983) from a natural recruitment study at Rolley Lake, is that stocking targetsmay not account sufficiently for natural production from inlet and outlet streams. Giventhe cost of hatchery trout ranging in mean size of 20-40 g, Lister suggests this practicewas inefficient because percent harvest of stocked rainbow trout was estimated to besmall (only 1 to 15 % and 9 to 22 % at Deer and Weaver Lakes, respectively). Naturalproduction was evidently significant and at that time unaccounted for in an applied lakestocking formula. Since then stocking of rainbow has been eliminated at Deer Lake, andstocking of cutthroat trout have been reduced by 60 % from 9,000 to 3,500 annually.Similar re-examinations of other cutthroat-rainbow lakes (e.g., Rolley Lake) to accountfor natural production is advisable where possible.Generally the classification of the Sunshine Coast lakes (particularly the chains of PowellRiver lakes) as wild cutthroat lakes is a sound management decision that only requiresmore innovative use of regulations plus some selective investments in stream restoration.Sufficient age 1-3 parr recruits from inlet and outlet nursery streams are required tosupport premier wild cutthroat lake fisheries over the long-term. Thus, stream habitatrestoration should be a high priority for those wild cutthroat lakes with greater thanaverage natural productivity and high recreational demand.6. LOWER MAINLAND REGION CUTTHROAT TROUT FISHERIESThe largest river fishery in the Lower Mainland Region takes place in the lower FraserRiver, consisting primarily of a multi-species “bar fisheries” during the salmon season.80 % of participants in these “bar fisheries” have reported that they are angling forsalmon, trout and char (Schubert 1992). In addition, the “cutthroat season” extendsthroughout the winter. River fisheries are documented on all Lower Mainland riversalong the coast and including the lower Fraser River, particularly the Harrison-Chehalis,Alouette, Stave, Vedder Canal and Nicomekl-Little Campbell. The smaller sloughfisheries target some of the same Fraser stocks and include: Nicomen; Maria; Mountain;Wahleach; and other sloughs. The estuary and beach fisheries are largely directed at theSunshine Coast and Crescent Beach-White Rock, with small fisheries along Howe Soundand the Powell River coastlines, many of which are guarded secrets (J. Roberts, pers.comm. 2004). The river fisheries on migratory lake stocks are the least understood butexamples are Harrison and Pitt systems. In the Harrison River watershed, cutthroat likelymigrate into Harrison River, Big Silver Creek and Lillooet River to feed on dislodgedsalmon eggs and carcasses in the autumn and emergent/migrating fry in the spring.