Study

Reduction of brown trout, Salmo trutta L., salmon, S. salar L., and rainbow trout, Oncorhynchus mykiss (Walbaum), smolt bycatches in eel pound nets

  • Published source details Dieperink C. & Rasmussen P.C. (1997) Reduction of brown trout, Salmo trutta L., salmon, S. salar L., and rainbow trout, Oncorhynchus mykiss (Walbaum), smolt bycatches in eel pound nets. Fisheries Management and Ecology, 4, 189-197.

Actions

This study is summarised as evidence for the following.

Action Category

Modify fishing trap/pot configuration

Action Link
Marine Fish Conservation
  1. Modify fishing trap/pot configuration

    A replicated, controlled study in 1992–1993 of five areas in a shallow estuary in the Kattegat, Denmark (Dieperink & Rasmussen 1997) found that modifications made to eel pound nets (fine-mesh, passive fish traps) reduced the capture of unwanted young brown trout Salmo trutta and, for one of two methods, salmon Salmo salar and rainbow trout Oncorhynchus mykiss, compared to nets fished without the modifications. The first of two modifications, submerging the pot net (the last enclosure in the net before the fyke net – akin to a codend), reduced catches of all species: by 91% for brown trout; 86% for salmon; and 75% for rainbow trout. The second, raising the guard net (located at the entrance to the pound net) to the surface using floats reduced numbers of brown trout (raised: 5–25 fish, not raised: 14–60 fish) but not salmon (raised: 6–18 fish, not raised: 13–15 fish) or rainbow trout (raised: 2–4 fish, not raised: 1–2 fish). In addition, catches of legal-sized individuals of the target eel Anguilla anguilla were similar for both comparisons. Pound net fishing was done in April/May 1992 and 1993 at five locations in the Randers Fjord estuary (22 km2), eastern Jutland, in 2–4 m depth. Every one or two days, pound nets were changed from a standard configuration to a modified one, either with a surface floating guard net or with submerged pot net, and vice versa. For the submerged nets, three different depths were fished: 55, 75 and 100 cm below sea level. The daily catch in each pound net was recorded as the number of each species from both the pot and fyke net sections within a 24 h period.

    (Summarised by: Natasha Taylor)

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