Toward an Ecosystem Approach to Bottom Trawling in Canada

DRAGGING OUR ASSETS9Seventy-five per cent of Canada’s Pacific Exclusive Economic Zone is considered as abyssalwaters greater than 1,000 metres, which is mostly beyond the current maximum trawlingdepth in B.C. of 1,200 metres. The actual area trawled in non-abyssal waters is about 36per cent, or six times greater than the area claimed by industry. Ecosystem-based policyand regulation require a better understanding of trawl distribution in relation to habitattype on both the Atlantic and the Pacific coasts as a necessary first step.Pacific CoastIn November 2006, DFO produced a paper examining the spatial extent of bottom trawlingby commercial groundfish fisheries in Canada’s Pacific waters. 23 This analysis concludedthat between 1996 and 2005, a cumulative total of 38,320 square kilometres of the oceanfloor had been contacted by bottom trawling based on one-by-one kilometre grid squares. 24Further analysis by the David Suzuki Foundation found that the spatial extent of bottomtrawling was very intensive in some depths and some areas. For example, along the west coastof Vancouver Island in the depth range of 150 to 1,200 metres, 97 per cent of the area hadbeen contacted by bottom trawl gear over the last decade based on presence and absence oftrawling in one-square-kilometre grid cells (Table 1, Figure 3). In the depth range of 150 to500 metres, 100 per cent of the area had been contacted by trawl gear over this same timeperiod. Bottom trawling has been conducted for approximately 60 years throughout muchP a c i f i c C o a s t B o t t o m T r a w l P r o f i l eFisheries using bottom trawling in Pacific Canada: groundfish and shrimp.Percent of total seafood landings by bottom trawl:20 ~17 per centGroundfishNumber of groundfish bottom-trawl licences: 142Number of active groundfish bottom-trawl licences: ~74Primary species caught (descending order): Arrowtooth flounder, Pacific oceanperch, Dover sole, yellowtail rockfish, yellowmouth rockfish, lingcod, rock sole, spinydogfish, silvergray rockfish, big skate, Pacific cod and English sole.Total footprint (see description in text): ~38,000 km 2Hours of bottom trawling per year: 30,000 - 40,000Habitat type trawled21: Sand and gravels (~40 per cent of trawled area), mud (30 percent), bedrock (~25 per cent), other (~five per cent).Average catch: 38,500 tonnes (~23 per cent of catch is discarded).Shrimp TrawlNumber of shrimp trawl licences: 248 eligible licensesNumber of active shrimp trawl licences 22 : ~80Primary species caught (descending order): smooth pink, northern pink, andsidestripe shrimpTotal footprint: UnknownShrimp trawling grounds available: ~11400 km 2Hours of trawling per year: Decline from ~84,000 hrs/yr to ~23,000 hrs/yr (2005)Habitat type: soft bottoms, mud and sand