Effectiveness of bycatch reduction devices (BRDs) in the ocean shrimp (Pandalus jordani) trawl fishery

Published source details Hannah R.W. & Jones S.A. (2007) Effectiveness of bycatch reduction devices (BRDs) in the ocean shrimp (Pandalus jordani) trawl fishery. Fisheries Research, 85, 217-225.
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This study is summarised as evidence for the following.

	Action	Category
	Fit a size-sorting escape grid (rigid or flexible) to a prawn/shrimp trawl net Action Link

Fit a size-sorting escape grid (rigid or flexible) to a prawn/shrimp trawl net

A before-and-after study in 1981–2005 of an area of seabed in the Pacific Ocean off the coast of Oregon, USA (Hannah & Jones 2007) found that the requirement to use rigid or flexible (mesh) size-sorting escape grids in shrimp trawl nets led to an overall reduction in catches of unwanted fish in an ocean shrimp Pandalus jordani fishery, compared to historical pre-use levels. Data were not tested for statistical significance. For four different types of escape grid, the amount of unwanted fish catch in the period after grids were introduced (2002–2005) was 6.5–13.3% of the total catches, compared to 32–61% unwanted fish catch in the years before grids were introduced (1981–2000). In 2005, catches of unwanted fish were 77–88% lower than the years from 1981–2000. In addition, catch rate and percentage of unwanted catch was significantly related to grid type and bar spacing (see paper for grid types). The use of a rigid or soft-mesh escape grid device to reduce unwanted catch was fully mandated in the ocean shrimp fishery in 2003 but grids were in use prior to this. Fisheries catch data post-grid use were collected in 2002–2005 by observers deployed on vessels operating in the fishery off the coast of Oregon. Historical catch data from 1981–2000 for nets without a grid or panel, were obtained from published and unpublished research sampling and survey records. See paper for list of fish species caught.

(Summarised by: Natasha Taylor)