Carter and others 



Chapter 27 



Mortality in Gill Nets 



fisheries patrol boat, or were found floating in the water. All 

 birds were killed between 1 1 June and 17 July in multifilament 

 nylon nets, 135-375 m in length, less than 10 m in depth, with 

 mesh sizes of 10-13 cm. Most murrelets were killed at night 

 off Cape Beale and south Trevor Channel near Bamfield 

 where large numbers of boats (average about 70/census) 

 fished in densities of 1 -4 boats/km 2 . In the same area, Marbled 

 Murrelets also occurred in large numbers (average about 

 266/census) and in high densities (average 11.3 birds/km 2 ). 

 Murrelets also were observed in small flocks sitting and 

 diving near nets during the day and may have been attracted 

 to nets to feed on small fish. Other details on gill-net mortality 

 in Barkley Sound can be found in Carter and Sealy (1984). 



Carter and Sealy (1984) estimated a minimum of 175- 

 250 murrelets were killed in 1980, representing 6.2 percent of 

 the breeding population or 7.8 percent of the potential fall 

 population. They pointed out that the long-term impacts of 

 such mortality could be great, but the degree of impact depended 

 upon continued high fishing effort in Barkley Sound. In August 

 1987 and December 1989, local people in Bamfield indicated 

 that gill-net fishing had not occurred every year since 1980 

 (Carter, unpubl. data; see brief reference in DeGange and 

 others 1993). Nonetheless, gill-net mortality may have 

 contributed to the decline (>50 percent) of Marbled Murrelets 

 that has been estimated in Trevor Channel and Barkley Sound 

 between 1979-1980 and 1992-1994 (Burger, this volume b; 

 Kelson, pers. comm.). However, a large decline (about 40 

 percent) also has occurred in Clayoquot Sound, further west 

 on the west coast of Vancouver Island, where gill-net fishing 

 does not occur (Kelson and others, in press). This decline in 

 Barkley Sound probably reflects losses of old-growth forest 

 habitat and mortality from the Nestucca oil spill, in addition to 

 gill-net mortality (Burger, this volume b; Carter and Kuletz, 

 this volume; Rodway and others 1992). The decline in Clayoquot 

 Sound has been attributed mainly to the loss of nesting habitats 

 in old-growth forests (Kelson and others, in press). 



Marbled Murrelets were not recovered from purse seines 

 in Barkley Sound in 1979-1982, although hundreds of 

 Common Murres were recovered (Carter, unpubl. data in 

 DeGange and others 1993). Similarly, murrelets were not 

 observed among floating carcasses of Common Murres off 

 Carmanah Point north of Cape Flattery on the west coast of 

 Vancouver Island in Statistical Areas 20, 21, and 121 in 

 August 1979 (Carter, unpubl. data in Vermeer and Sealy 

 1984; DeGange and others 1993). Marbled Murrelets were 

 not reported among Ancient Murrelets (Synthliboramphus 

 antiquus) and Rhinoceros Auklets killed in gill nets in July 

 1970-1971 and 1978 near Langara Island in the Queen 

 Charlotte Islands (Statistical Area 1)( Vermeer and Sealy 

 1984). However, Marbled Murrelets were caught frequently 

 on sports fishing lures near Campbell River in the 1960s 

 (Campbell 1967). In 1979-1980, sports fishermen in Barkley 

 Sound also reported catching murrelets on sports fishing 

 lures (Carter, unpubl. data). 



To examine the potential for gill-net mortality of Marbled 

 Murrelets in British Columbia, we have summarized recent 

 data on gill-net and seine fishing effort for all Statistical 



Areas in 1992 (table 1). Gill-net fishing occurred in almost 

 all areas, but the largest gill-net fisheries (>2,000 days fished) 

 occurred in Statistical Areas 3, 4, 9, 10, 12, 14, 21, and 23 in 

 the general vicinity of the Southeast Alaska border, Prince 

 Rupert, Rivers Inlet, Smith Inlet, Queen Charlotte/Johnstone 

 straits, Comox/Qualicum, Pachena Point to Bonilla Point, 

 and Barkley Sound, respectively (see figs. 3 and 4). Marbled 

 Murrelets occur throughout the coasts of British Columbia, 

 including almost all fishing Statistical Areas (Campbell and 

 others 1990, Rodway and others 1992, Vermeer and others 

 1983). At present, it is difficult to assess the overall degree 

 of gill-net mortality in British Columbia, given incomplete 

 knowledge of the at-sea distribution and population sizes. 

 However, hundreds to thousands of murrelets may be killed 

 annually due to the extensive nature of these fisheries 

 throughout the province. 



In five statistical areas (3, 4, 9, 10, and 23), extensive 

 fishing effort occurred in July when large numbers of murrelets 

 are feeding chicks at the nest, aggregate in high densities, 

 and may be more susceptible to mortality (Carter and Sealy 

 1984, 1990). Notably, Barkley Sound is among these earlier 

 fisheries. Heavy gill-net fishing effort occurs mainly in the 

 fall (August to November) in many Statistical Areas (table 

 1) which may avert high levels of mortality. Murrelets are 

 undergoing a flightless pre-basic molt during this period and 

 tend to occur in lower densities and closer to shore in many 

 areas (Carter and Stein, this volume). 



In 1992, extensive seine fishing effort tended to occur in 

 conjunction with high gill-net fishing effort in most statistical 

 areas (table 1). However, in Barkley Sound in 1979-1980, 

 seine fishing occurred in a different area (with low densities 

 of murrelets) than where gill-net fishing occurred, apparently 

 to prevent interference. Seabird mortality (primarily Common 

 Murres) in seine nets did occur in the fall in Trevor Channel 

 when gill-net fishing had moved farther up the Alberni Canal 

 and seine fishing occurred in central Trevor Channel (Carter 

 and Sealy 1984). 



Gill-net and seine fisheries should be examined 

 throughout British Columbia for bycatch of Marbled Murrelets 

 and other seabirds. Extensive mortality may be occurring 

 annually in many areas. Efforts should be taken to reduce or 

 stop such mortality immediately. 



Washington 



In Puget Sound and the Columbia River area (fig. 5), 

 large gill-net and purse seine fisheries, which target several 

 species of salmon, have existed since at least the 1940s. 

 These fisheries peaked in the 1970s and 1980s and have 

 recently declined because of reduced catch, increasing 

 regulation, and declining salmon populations. These fisheries 

 involve both native and non-native fishermen and are managed 

 by state (Washington Department of Fish and Wildlife 

 [WDFW]) and federal (National Marine Fisheries Service 

 [NMFS]) agencies, native nations, and tribal (Northwest 

 Tribal Fish Commission) and non-tribal (Bureau of Indian 

 Affairs [BIA]) fishing groups. 



278 



USDA Forest Service Gen. Tech. Rep. PSW-152. 1995. 



