Fin whales may break through or carry away fishing gear. Whales carrying gear may die at a later time due to trailing fishing gear, become debilitated or seriously injured, or have normal functions impaired, but with no evidence of the incident recorded. More
information is needed to evaluate the serious injury and mortality of fin whales from entanglement. Fin whales are occasionally killed or injured by inshore fishing gear (e.g., gillnets and lobster lines) off of eastern Canada and the east coast of the United States (Read 1994; Lien 1994; Waring et al. 1997). Fin whales apparently are entangled in inshore fishing gear in the North Pacific, but only very rarely (Barlow et al. 1994, 1997). G.1.1 Global
Globally, the ranking of the threat posed by the incidental capture of animals by gillnet, trawl, pot/trap, sink gillnet, and purse seine fishing practices to fin whale recovery was based on the assertion that while the uncertainty of information is medium, the severity of this threat is low, and the overall impact to the recovery of fin whale populations is considered low (Table 1). Rankings of these threats for some populations are also shown in the table and discussed below.
July 2010 I-18 NMFS
Western North Atlantic Ocean
In the Western North Atlantic2, there were 4 confirmed entanglements of fin whales from 2002 to 2006; two resulted in mortalities and two resulted in serious injury (Waring et al. 2009). In addition to those mentioned above, there were four additional records of entanglement within the period that either lacked substantial evidence to make a serious injury determination or did not provide the detail necessary to determine if an
entanglement had been a contributing factor in the mortality (Waring et al. 2009). The ranking of the threat posed by the incidental capture of animals in the western North Atlantic and Nova Scotia from lobster and mixed species pot/trap and sink gillnet fishing practices to fin whale recovery was based on the assertion that there is a low uncertainty with regard to impacts to individual animals and the impact to the recovery of fin whale populations due to these fishing practices is considered low (Table 1).
U.S. Pacific Ocean
In the North Pacific, Heyning and Lewis (1990) made a crude estimate of about 73 rorquals killed per year in the southern California offshore drift gillnet fishery during the 1980s. Some of these may have been fin whales and some of them sei whales. Some balaenopterids, particularly fin whales, may also be taken in the drift gillnet fisheries targeting sharks and swordfish along the Pacific coast of Baja California, Mexico (Barlow et al. 1997) and from the California/Oregon/Washington stock. While the California/Oregon drift gillnet fishery killed/seriously injured fin whales, since the leatherback sea turtle (Dermochelys coriacea) conservation area was implemented in 2001 off central California and Oregon (66 FR 44549), no fin whales have been observed taken in this fishery. Based on the most recent observer data, the average fin whale bycatch in the offshore drift gillnet fishery was approximately zero per year from 2002– 2006 (Carretta et al. 2009) and between 1994 and 2002, no interactions with fin whales were observed in the Hawaii-based longline fishery (Forney 2004). Between 2002 and 2006, there was one observed incidental mortality of a fin whale in the Bering
Sea/Aleutian Islands pollock trawl (Angliss and Allen 2009). The ranking of the threat posed by the incidental capture of animals off of California/Oregon/Washington from gillnet and from the Northeast Pacific from the pollock trawl fishing practices to fin whale recovery was based on the assertion that there is a low uncertainty with regard to impacts to individual animals and the impact to the recovery of fin whale populations due to these fishing practices is considered low (Table 1). In Hawaii, the ranking of the threat posed by the incidental capture of animals from the longline and pot/trap fisheries was also based on the assertion that there is a low uncertainty with regard to impacts to individual animals and the impact to the recovery of fin whale populations due to these fishing practices is considered low (Table 1). However, Heyning and Lewis (1990) suggested that most whales killed by offshore fishing gear do not drift close enough to shore to strand on beaches or be detected floating in the nearshore corridor, where most whale watching and other types of boat traffic occur. Thus, the small amount of
2 The IWC has proposed stock boundaries for North Atlantic fin whales of the eastern United States, Nova
Scotia, and the southeastern coast of Newfoundland and are believed to constitute a single stock, however, whether the current stock boundaries define biologically isolated units has long been uncertain (Waring et
July 2010 I-19 NMFS documentation should not be interpreted to mean that entanglement in fishing gear is an insignificant cause of mortality.
Southern Hemisphere
It is not known if fin whales interact with fisheries in the Southern Hemisphere. However, the Convention on the Conservation of Antarctic Marine Living Resources (CCAMLR) was established chiefly as a result of concerns that increasing krill catches in the Southern Ocean could have serious effects on the population of krill. Krill is a major and vital part of the Antarctic food web and so disturbances to populations could have major and far-reaching effects on the whole ecosystem. Typically, krill is fished using trawl gear. In addition to krill fishing, the Patagonia toothfish is also a target species for fisheries in Antarctica and those fisheries likely use hooks and lines or demersal longline gear for their catch. It is assumed, based on the types of fisheries and fishing gear that could be used in the Southern Hemisphere, interactions are possible and the small amount of documentation should not be interpreted to mean that entanglement in fishing gear is an insignificant cause of mortality. The impact to the recovery of fin whale populations due to these fishing practices is considered low (Table 1).