19 



CHAFrER3 



HABITAT MANAGEMENT 



When fish habitat is lost or threatened, the 

 fish stocks and species which depend upon it 

 for food, protection and reproduction are 

 similarly lost or threatened. In short, if habi- 

 tat goes, so eventually do the fish .... 



BRITISH COLUMBIA WILDLIFE FEDERATION' 



Concern for the protection of fish habitat is wide- 

 spread. Apprehensions about habitat deterioration and 

 about our policies for controihng it are expressed not 

 only by fishermen but also by many others who have a 

 general concern for the natural environment and who 

 often look to fish as a barometer of environmental integ- 

 rity. 



The di.scussion offish resources in Chapter 2 dealt with 

 the condition of the stocks. In a more fundamental sense, 

 the resource base is the natural environment that sup- 

 ports fish. Unless the quality and productivity of the 

 aquatic habitat is maintained, even the best of stock man- 

 agement will be to no avail. Whenever the environment 

 that fish depend on for food or reprcxluction is damaged. 

 the fish are threatened. Thus, the protection of aquatic 

 habitat is considered by many to be the "first and fore- 

 most" problem of fisheries policy. - 



The most valuable stocks on the Pacific coast — 

 salmon — are unusually .sensitive to habitat disturbances 

 because of their dependence on freshwater environments 

 for critical stages of their life cycles. Man's activities in 

 watersheds, even hundreds of miles from the ocean, can 

 upset the habitat and hence also the populations of fish. 

 On the Pacific coast this presents especially difficult 

 resource management problems. The mountain 

 watersheds that support these valuable stocks also con- 

 tain exceptionally valuable timber, rich mineral deposits, 

 hydroelectric opportunities, the best agricultural land, as 

 well as the natural transportation corridors and urban 

 development centres. Estuaries are the common coastal 

 centres of population and commerce. As a result, most 

 resource development and industrial activity impinge on 

 the habitat offish. 



All this leads to a conclusion that should be made clear 

 at the outset of this chapter: environmental protection is 



more crucial on the Pacific coast than elsewhere. Stand- 

 ards of pollution control and habitat protection appropri- 

 ate for Ontario or Saskatchewan may not be sufficient to 

 protect the fisheries of the Pacific coast. 



PRESSURES ON FISH HABITAT 



The habitat of many of our stocks has already sufliered 

 damage. The impacts of human population growth, con- 

 tinuing resource development and industrial expansion, 

 new technology, and generally increasing demands on 

 land and water have taken their toll, and in the opinion 

 of some obser\'ers. the habitat of some of our stocks is in 

 a state of crisis. 



Quantifying the impact on fish stocks of past damage 

 to their habitat is virtually impossible. First, our histori- 

 cal statistics are inadequate. Second, damage from log- 

 ging and other activities may not be permanent: streams 

 have the power, over time, to rehabilitate and cleanse 

 themselves from some kinds of damage, although the 

 peritxJ of time for such recovery may be measured in 

 many decades. Third, the specific adverse impact on 

 stocks of overfishing and habitat damage are not always 

 independent: one can aggravate the effect of the other. 

 .\nd finally, losses of habitat are often difficult to iden- 

 tify: they are frequently the result of a host of sublethal 

 changes and indi\ idually minor pressures on the environ- 

 ment which. collectivelN. can reduce or destroy its ability 

 to suppiirt fish. Thu.s. in attempting to identify the proba- 

 ble impact of a de\elopment, we ha\e no point of refer- 

 ence in terms of information on the predevelopment. 

 pristine condition since all stocks have been subjected to 

 fishing pressures and perturbations for decades. 



For these and other reasons, identifying the potential 

 impact of a proposed development is also diflicult. In 

 attempting to do so, we may underestimate the long-term 

 adverse eflfects. Combined with a multiplicity of adverse 

 eflects from various other environmental insults, as well 

 as the pressures of commercial, sport and Indian fisher- 

 ies, the effects of a single project cannot easily be isolated 

 and identified even by after-the-fact observation of stock 

 •Strength. 



In particular watersheds or sites, the major adverse 

 effect on fish may be from any one of a variety of sources 

 of environmental damage. But in the Pacific region gen- 

 erally, the greatest potential threats to the habitats of 

 .salmon and related species are dams and diversions, for- 

 estry, mining and foreshore developments. 



Dams. Slides and Diversions 



Obstructions in streams present the most direct barri- 

 ers to mature fish on their spawning migrations and to 

 young fish making their way to sea. Environmental 

 changes that impose stresses, particularly changes in 



