A Novel Tool to Mitigate By-Catch Mortality of Baltic Seals in Coastal Fyke Net Fishery

Oksanen, Sari; Ahola, Markus; Oikarinen, Jyrki; Kunnasranta, Mervi

doi:10.1371/journal.pone.0127510

Cited by 5 publications

(3 citation statements)

References 31 publications

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“…Their foraging areas were more clearly clustered to the northern Bothnian Bay compared to juveniles. The juveniles were mainly captured in fyke nets earlier in fall, which is in line with the by-catch records [ 38 ]. The foraging areas of the tracked seals partly overlapped with MPAs and Natura 2000 sites especially in the identified foraging hot spots.…”

Section: Discussionsupporting

confidence: 66%

“…1 ). Fyke nets ( n = 4) were equipped with “seal socks” allowing the seals to access the surface to breathe [ 38 ] and were set for fishing by commercial fishermen from May to October-November. In addition, floating seal nets (mesh size 180 mm, height 4 m, length 80 m, net material 0.7 monofil, Hvalpsund net A/S) were used for capturing seals during October and November.…”

Section: Methodsmentioning

confidence: 99%

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Identifying foraging habitats of Baltic ringed seals using movement data

et al. 2015

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BackgroundIdentification of key foraging habitats of aquatic top predators is essential for designing effective management and conservation strategies. The Baltic ringed seal (Phoca hispida botnica) interacts with anthropogenic activities and knowledge of its spatial ecology is needed for planning population management and mitigating interactions with coastal fisheries. We investigated habitat use and foraging habitats of ringed seals (n = 26) with satellite telemetry in the northern Baltic Sea during autumn, which is important time for foraging for ringed seals. We used first passage time (FPT) approach to identify the areas of high residency corresponding to foraging areas.ResultsTracked seals showed considerable movement; mean (±SD) home ranges (95 % adaptive local nearest-neighbour convex hull, a-LoCoH) were 8030 ± 4796 km2. Two seals moved randomly and foraging areas could not be identified for them. The majority (24/26) of the studied seals occupied 1–6 main foraging areas, where they spent 47 ± 22 % of their total time. Typically the foraging areas of individuals had a mean distance of 254 ± 194 km. Most of the seals (n = 17) were “long-range foragers” which occupied several spatially remote foraging areas (mean distance 328 ± 180 km) or, in the case of two individuals, did not concentrate foraging to any particular area. The other seals (n = 9) were “local foragers” having only one foraging area or the mean distance between several areas was shorter (67 ± 26 km). Foraging areas of all seals were characterised by shallow bathymetry (median ± SD: 13 ± 49 m) and proximity to the mainland (10 ± 14 km), partly overlapping with protected areas and coastal fisheries.ConclusionsOur results indicate that in general the ringed seals range over large areas and concentrate feeding to different—often remote—areas during the open water season. Therefore, removal of individuals near the fishing gear may not be a locally effective method to mitigate seal depredation. Overlap of foraging areas with protected areas indicate that management of key foraging and resting habitats could to some extent be implemented within the existing network of marine protected areas.Electronic supplementary materialThe online version of this article (doi:10.1186/s40462-015-0058-1) contains supplementary material, which is available to authorized users.

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Section: Discussionsupporting

confidence: 66%

Section: Methodsmentioning

confidence: 99%

Identifying foraging habitats of Baltic ringed seals using movement data

et al. 2015

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“…In Finland and Sweden, traps are permitted for the live capture of grey seals which are then killed with a shot to the head (Ministry of Agriculture and Forestry, 2007;Lehtonen and Suuronen, 2010;Mörner et al, 2013;Oksanen et al, 2015). In walrus hunting in Greenland, it is compulsory to harpoon the walrus before firing the shot which will kill it, to prevent the animal from sinking (NAMMCO, 2016b) or, presumably, escaping wounded.…”

Section: Table 1 Herementioning

confidence: 99%

A review of seal killing practice in Europe: Implications for animal welfare

Nunny¹,

Simmonds

Butterworth

2018

Marine Policy

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Predator control is also considered necessary in some places for preventing the escape into the wild of farmed fish (Butler et al., 2005). In Scotland, seal management has also had to take into consideration the required protection of Atlantic salmon (Salmo salar), common seals (Phoca vitulina) and grey seals (Halichoerus grypus) under the European Union (EU) Habitats Directive (Butler et al., 2006; Butler et al., 2015). Some European nations permit seal killing for commercial reasons to sell the skin, blubber and meat for profit (EFSA, 2007). Norway, Greenland and Russia carry out commercial hunts targeting harp seals (Pagophilus groenlandicus), and Greenland's hunters, many of whom are considered traditional subsistence hunters, also target bearded (Erignathus barbatus), hooded (Cystophora cristata) and ringed seals (Pusa hispida) as well as walruses (Odobenus rosmarus) (EFSA, 2007; Ministry of Fisheries, Hunting and Agriculture, 2012). Within the EU, seal products can only be placed on the market if they result from a hunt conducted by Inuit or other indigenous communities, if the hunt has been traditionally carried out by the community, if it contributes to the subsistence of the community and is not carried out for commercial reasons and if it "has due regard to animal welfare" (European Parliament 2009 and 2015). The EU Regulation on the trade in seal products has not prevented seal hunting in some places, for example Finland, but does mean that seal export markets cannot be developed (Meek et al., 2011). Seal hunting is a recreational activity in some regions and seals are regarded as game animals meaning that, even if they are killed for management reasons, the carcase may be collected for the personal use of the hunter. This occurs for example in Åland (an autonomous Swedish-speaking province of Finland),

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Technical mitigation to reduce marine mammal bycatch and entanglement in commercial fishing gear: lessons learnt and future directions

Hamilton

Baker

2019

Rev Fish Biol Fisheries

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A Novel Tool to Mitigate By-Catch Mortality of Baltic Seals in Coastal Fyke Net Fishery

Cited by 5 publications

References 31 publications

Identifying foraging habitats of Baltic ringed seals using movement data

Identifying foraging habitats of Baltic ringed seals using movement data

A review of seal killing practice in Europe: Implications for animal welfare

Technical mitigation to reduce marine mammal bycatch and entanglement in commercial fishing gear: lessons learnt and future directions

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