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E'.vcr-fxpi"!*-!'"!; iiih.m and commercial development 

 has destroyed or degraded much of the stream hahitat m 

 and around cities, particularly in the major centres of the 

 lower mainland and southern Vancouver Island. 

 l\'structii>n o( fish habitat in these areas takes place bit 

 by bit. with cuKertmg of creeks under rivids and streets, 

 dyking, streambed channeling, removal of sireamside 

 cover and installation of drainage systems. Seepage of a 

 host of toxic substances from waste disposal landfills and 

 other sources is a serious prt>blem in many areas. Streams 

 that once supp<.>rted salmon have simply disappeared in 

 the wake of hou.sing and industrial development, particu- 

 larly in greater Vancouver. Victoria, and the lower Fraser 

 region. Others are seriously degraded; notable examples 

 brought to the attention of this Commi.ssion include the 

 Cixiuitlam River. Brunette River and McNally Creek. 

 Only recently have municipal authorities begun to think 

 systematically about the preservation of natural streams 

 within their boundanes. 



Oil Spills 



An environmental threat that has attracted worldwide 

 concern during the last decade is that of oil spills, espe- 

 cially those that result from accidents involving large 

 tankers and drilling rigs. The deficiencies of modem tech- 

 nology in coping with large spills and the damage they 

 can do to sea life have been demonstrated time and 

 again. 



Some petroleum products are lethal to adult fish even 

 at low concentrations.*' but by far the most acute effects 

 are on fish in the egg and larval stages and on other 

 marine organisms that they depend on for food. The 

 impact is most severe in estuaries and inshore waters 

 because of their importance as spawning, rearing and 

 feeding areas for fish. 



Of the major commercial species along the coast of 

 British Columbia, herring is probably the most vulner- 

 able to oil spills. These fish spawn on algae and other 

 intertidal vegetation, or on rocks when no vegetation is 

 available. After they hatch, the larvae drift with the cur- 

 rents near the surface. Oil drifting inshore can kill both 

 eggs and larvae. Shrimps, prawns, crabs and a variety of 

 shellfish and bottom fish are similarly susceptible in their 

 larval stages. Some of these do not now support 

 significant fisheries but are abundant and important in 

 the food chains of commercial species. Even some of the 

 more resistant .species would be weakened or tainted by 

 oil and thereby rendered unusable. 



All species, but particularly bottom fish, are vulnerable 

 to chemical dispersants, emulsifiers and sinking agents 

 used to clean up oil spills. Sometimes they are toxic in 

 themselves, but even when they are not, sinking hydro- 



carbons can ivnson lish cillici ilircctly or through the 

 lotnl cli.im. 



We are (orlunalc that few major oil spills have 

 occurreil otf the coast .A' British Columbia and, on the 

 whole, permanent damage to fish from this source has not 

 been great. But expanding domestic and U.S. tanker 

 traffic, oil port developments, and especially the possibil- 

 ity of oil drilling activity, pose increasing haz^iirds to fish 

 against which available technology offers only limited 

 protection. 



Other Impacts 



Ihe threats to fish habitat mentioned above are only 

 some of the most conspicuous; others include road, rail- 

 road, pipeline and transmission line construction. The 

 incremental impact of habitat contamination from non- 

 point sources, such as agriculture, is another concern. 

 The contaminants are often sublethal and difficult to 

 detect or quantify. During the past few years, the high 

 price of gold has resulted in greatly increased placer min- 

 ing activity with attendant damage to fish habitat from 

 hydraulicking. suction dredging and stream diversions. 



Important al.so are natural variations in the environ- 

 ment. Fishermen as well as biologists know that unpre- 

 dictable shifts in ocean currents can profoundly alter the 

 migration patterns of stocks; droughts and low 

 streamflows during the summer can affect rearing fish 

 and leave spawning grounds inaccessible; extreme cold 

 or heavy rains (such as occurred in 1980) can devastate 

 eggs overwintering in stream gravel, and so on. The 

 impact of such events is usually most serious when the 

 stocks are already weakened by other damage to their 

 habitat or, especially, by overfishing. 



POLICY FOR HABITAT iVlANAGEMENT 



Thus, the environment that supports our Pacific fisher- 

 ies is being assaulted from many directions. To protect it 

 so that our fish resources can be maintained, we will need 

 a strong and comprehensive habitat management policy. 

 If left unchallenged, these activities would undoubtedly 

 lead to serious, and in many cases, irreparable harm to 

 Pacific fisheries. 



Like the soil that nurtures agncuitural crops, fish habi- 

 tat can be viewed as a natural resource in its own right. 

 When harmful waste and other materials are deposited 

 into water, when migrating fish are denied passage 

 through streams, or when aquatic and marine environ- 

 ments are impaired by other human activities, nature's 

 ability to produce fish is hampered. Seen in this light, 

 concerns about habitat quality go hand in hand with 

 fisheries management and enhancement, the subjects of 

 the following chapters. Depleted wild stocks can be 

 restored by more effective fisheries management and cer- 



