Temporal and regional patterns in seal-induced catch and gear damage in the coastal trap-net fishery in the northern Baltic Sea: effect of netting material on damage

Reduction of seal-induced catch and gear damage by modification of trap-net design: Design principles for a seal-safe trap-net

“…Materials in which fish become entangled are most prone to seal-induced damage. This is in line with the observations of Lehtonen and Suuronen (2004) and Kauppinen et al (2005). In addition, rigging of wings, middle chambers and funnels should be designed so that there are no steep netting angles which may disturb fish when avoiding an attacking seal.…”

“…The potential catch damage caused by seabirds was not separated from seal-induced damage. However, the damage to fishes observed in this study were of the type typically caused by grey seal (see Kauppinen et al, 2005). Hauls with no catch or remains of damaged fish were excluded when analyzing the seal-induced catch damage proportions.…”

“…Since the early 1990s, seal-induced catch damage has increased dramatically in the trap-net fishery for salmon (Salmo salar) and whitefish (Coregonus lavaretus) in the northern Baltic Sea, particularly along the coast of Gulf of Bothnia and Gulf of Finland (Baltscheffsky, 1997;Lunneryd and Westerberg, 1997;Westerberg et al, 2000;Kauppinen et al, 2005). Most damage is caused by the rapidly growing grey seal (Halichoerus grypus) population although the ringed seal (Phoca hispida botnica) also causes damage in the northernmost areas of the Gulf of Bothnia (e.g.…”

“…Most damage is caused by the rapidly growing grey seal (Halichoerus grypus) population although the ringed seal (Phoca hispida botnica) also causes damage in the northernmost areas of the Gulf of Bothnia (e.g. Westerberg et al, 2000;Kauppinen et al, 2005). In the most affected areas, more than 50% of salmon catches are damaged by seals.…”

Grey Seal Predation in Cod Gillnet Fisheries in the Central Baltic Sea

“…In addition to declining fish stocks and structural problems, the coastal fisheries in the Baltic Sea are also subjected to damage caused by grey seals (Halichoereus grypus). The grey seal population in the Baltic Sea has increased dramatically during recent decades (Hårding, 2007) and the seal-fisheries conflict has escalated in parallel with the population increase (Baltscheffsky, 1997;Lunneryd, 2001;Fjälling, 2005;Kauppinen et al, 2005;Westerberg et al, 2006). Fisheries using static gear in the north Baltic, where salmon (Salmo salar) and whitefish (Coregonus lavaretus) are the target species, have been considered to be the fisheries most exposed to seal damage.…”