Unanswered Forum Topics

A simple technical measure to reduce bycatch and discard of skates and sharks in mixed-species bottom-trawl fisheries

Study Type
Field study in the wild
Location
Minch and Stanton Banks
Target catch
Whitefish
Effect on bycatch species
Removing the 'tickler' chain resulted in decreased catches of sharks and skates
Effect on target catch
Catch rates for flatfish, haddock and whiting did not differ. Larger anglerfish were caught without the 'tickler' in place
Bycatch species
Reduction technique
Fishing Gear

A simple technical measure to reduce bycatch and discard of skates and sharks in mixed-species bottom-trawl fisheries

Study Type
Field study in the wild
Location
Minch and Stanton Banks
Target catch
Whitefish
Effect on bycatch species
Removing the 'tickler' chain resulted in decreased catches of sharks and skates
Effect on target catch
Catch rates for flatfish, haddock and whiting did not differ. Larger anglerfish were caught without the 'tickler' in place
Bycatch species
Reduction technique
Fishing Gear

A simple technical measure to reduce bycatch and discard of skates and sharks in mixed-species bottom-trawl fisheries

Study Type
Field study in the wild
Location
Minch and Stanton Banks
Target catch
Whitefish
Effect on bycatch species
Removing the 'tickler' chain resulted in decreased catches of sharks and skates
Effect on target catch
Catch rates for flatfish, haddock and whiting did not differ. Larger anglerfish were caught without the 'tickler' in place
Bycatch species
Reduction technique
Fishing Gear

A simple technical measure to reduce bycatch and discard of skates and sharks in mixed-species bottom-trawl fisheries

Study Type
Field study in the wild
Location
Minch and Stanton Banks
Target catch
Whitefish
Effect on bycatch species
Removing the 'tickler' chain resulted in decreased catches of sharks and skates
Effect on target catch
Catch rates for flatfish, haddock and whiting did not differ. Larger anglerfish were caught without the 'tickler' in place
Bycatch species
Reduction technique
Fishing Gear

Reducing bycatch in gillnets: A sensory ecology perspective

Submitted by morgaac on

This article reviewed bycatch mitigation methods that rely on sensory ecology to reduce interactions with sea birds, sea turtles, pinnipeds and blue-water fish. Panels containing patterns of low spatial frequency and high internal contrast can be used for all of these species. These panels are not likely to reduce catches of target species and are easy and inexpensive to apply. The authors suggest that sound signals on gillnets are not recommended for most bycatch species, excpet for cetaceans. Cetaceans require both visual cues and warning through echolocation.

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Canadian fisheryclosures provide a large-scale test of the impact of gillnet bycatch on seabird populations

Submitted by morgaac on

The authors investigated the effects of a large-scale gillnet closure on sea bird populations in Canadian waters. After a 1992 closure, breeding populations of bycatch-prone diving birds (auks and gannets) increased, with a corresponding decrease in surface-feeding scavengers such as gulls that are less prone to bycatch in gillnets but that do consume fisheries discards.

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Canadian fisheryclosures provide a large-scale test of the impact of gillnet bycatch on seabird populations

Study Type
Summary study
Location
Canada
Target catch
Cod and Atlantic salmon
Effect on bycatch species
Closure resulted in increased populations of common murres and auks but a decrease in gulls
Effect on target catch
None reported
Bycatch species
Reduction technique
Fishing Gear

Canadian fisheryclosures provide a large-scale test of the impact of gillnet bycatch on seabird populations

Study Type
Summary study
Location
Canada
Target catch
Cod and Atlantic salmon
Effect on bycatch species
Closure resulted in increased populations of common murres and auks but a decrease in gulls
Effect on target catch
None reported
Bycatch species
Reduction technique
Fishing Gear

Canadian fisheryclosures provide a large-scale test of the impact of gillnet bycatch on seabird populations

Study Type
Summary study
Location
Canada
Target catch
Cod and Atlantic salmon
Effect on bycatch species
Closure resulted in increased populations of common murres and auks but a decrease in gulls
Effect on target catch
None reported
Bycatch species
Reduction technique
Fishing Gear

Selective characteristics of a shark-excluding grid device in a Mediterranean trawl

Submitted by morgaac on

Trials were conducted using excluder grids on trawls targeting Norway lobster (Nephrops novegicus) and greater forkbeard (Phycis blennoides) in the Tyrrhenian Sea. The excluder grids were tested for their ability to reduce the incidental capture of blackmouth catshark (Galeus melastomus).  In order to estimate the number of escaped fish, covers were placed over the escape outlet before the grid and over the codend. The 90 mm excluder grid did not result in reduced catches of blacknouth catshark.

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Selective characteristics of a shark-excluding grid device in a Mediterranean trawl

Study Type
Field study in the wild
Location
Tyrrhenian Sea
Target catch
Norway lobster (Nephrops norvegicus) and greater forkbeard (Phycis blennoides)
Effect on bycatch species
90 mm excluder grid did not reduce catches of blackmouth catshark (Galeus melastomus)
Effect on target catch
90 mm excluder grid reduced catches of greater forkbeard and to a lesser extend Norway lobster
Bycatch species
Reduction technique
Fishing Gear

Selective characteristics of a shark-excluding grid device in a Mediterranean trawl

Study Type
Field study in the wild
Location
Tyrrhenian Sea
Target catch
Norway lobster (Nephrops norvegicus) and greater forkbeard (Phycis blennoides)
Effect on bycatch species
90 mm excluder grid did not reduce catches of blackmouth catshark (Galeus melastomus)
Effect on target catch
90 mm excluder grid reduced catches of greater forkbeard and to a lesser extend Norway lobster
Bycatch species
Reduction technique
Fishing Gear

Selective characteristics of a shark-excluding grid device in a Mediterranean trawl

Study Type
Field study in the wild
Location
Tyrrhenian Sea
Target catch
Norway lobster (Nephrops norvegicus) and greater forkbeard (Phycis blennoides)
Effect on bycatch species
90 mm excluder grid did not reduce catches of blackmouth catshark (Galeus melastomus)
Effect on target catch
90 mm excluder grid reduced catches of greater forkbeard and to a lesser extend Norway lobster
Bycatch species
Reduction technique
Fishing Gear