Study

Reduction of harbour porpoise (Phocoena phocoena) bycatch by iron-oxide gillnets

  • Published source details Larsen F., Eigaard O.R. & Tougaard J. (2007) Reduction of harbour porpoise (Phocoena phocoena) bycatch by iron-oxide gillnets. Fisheries Research, 85, 270-278

Actions

This study is summarised as evidence for the following.

Action Category

Use acoustically reflective fishing gear materials

Action Link
Marine and Freshwater Mammal Conservation
  1. Use acoustically reflective fishing gear materials

    A replicated, controlled study in 2000 of six pelagic sites in the North Sea, Denmark (Larsen et al. 2007) found that fishing nets made from an acoustically reflective material (iron-oxide) had fewer entanglements of harbour porpoises Phocoena phocoena than conventional nets. No porpoises were found in entangled in iron-oxide nets, whereas a total of eight porpoises (average 0.1 porpoises/km/day) were entangled in conventional nets. Average catch rates of target cod Gadus morhua were lower in iron-oxide nets (6–15 fish/km/day) than conventional nets (8–32 fish/km/day). Each of six sites was fished for three days with 4–8 strings (50 x 60 m gill nets) of each of two net types: high-density iron-oxide nets and conventional nylon nets. The authors did not find a significant difference in acoustic target strengths between the two net types (see original paper for details) and suggest that other factors (e.g. net colour, stiffness, mechanics) may have reduced porpoise entanglements. An observer on board a chartered commercial fishing vessel recorded the number of entangled porpoises and fish catches as the nets were hauled in September–October 2000.

    (Summarised by: Anna Berthinussen)

Output references

What Works in Conservation

What Works in Conservation provides expert assessments of the effectiveness of actions, based on summarised evidence, in synopses. Subjects covered so far include amphibians, birds, terrestrial mammals, forests, peatland and control of freshwater invasive species. More are in progress.

More about What Works in Conservation

Download free PDF or purchase
The Conservation Evidence Journal

The Conservation Evidence Journal

An online, free to publish in, open-access journal publishing results from research and projects that test the effectiveness of conservation actions.

Read the latest volume: Volume 18

Go to the CE Journal

Discover more on our blog

Our blog contains the latest news and updates from the Conservation Evidence team, the Conservation Evidence Journal, and our global partners in evidence-based conservation.


Who uses Conservation Evidence?

Meet some of the evidence champions

Endangered Landscape Programme Red List Champion - Arc Kent Wildlife Trust The Rufford Foundation Save the Frogs - Ghana Bern wood Supporting Conservation Leaders National Biodiversity Network Sustainability Dashboard Frog Life The international journey of Conservation - Oryx British trust for ornithology Cool Farm Alliance UNEP AWFA Butterfly Conservation People trust for endangered species Vincet Wildlife Trust