In the fishery business, a bycatch reduction device is a tool used to help prevent catching marine animals that are not meant to be caught. This helps reduce the harmful effects of fishing on the ocean environment.
Development
To help prevent the accidental capture of marine animals, the National Oceanic and Atmospheric Administration (NOAA) fisheries created and tested bycatch reduction devices (BRDs). These devices are openings in shrimp trawl nets that let unwanted fish and other aquatic animals escape, while shrimp, the target species, move toward the part of the net where they are collected. The design of BRDs works with standard bottom trawling methods and uses nets equipped with a turtle excluder device. BRDs are required in shrimp trawl nets used in federal waters of the Gulf of Mexico and South Atlantic regions.
A shark and ray bycatch reduction tool called SharkGuard, which uses electric pulses, was found to reduce the accidental capture of blue sharks by 91% and stingrays by 71% when used with commercial fishing gear in a longline tuna fishery in the Mediterranean Sea.
Legal imperative
In 1996, National Standard 9 was added to the Magnuson-Stevens Fishery Conservation and Management Act to help control the amount of bycatch. This standard requires reducing bycatch as much as possible and reducing the harm to fish that cannot be avoided. Congress added more rules to protect these fish under the Marine Mammal Protection Act and the Endangered Species Act. To follow these rules, NOAA Fisheries (National Marine Fisheries Service) created a continuing bycatch plan and published Amendment 10 to the Fisheries Management Plan of the Gulf of Mexico Fisheries Management Council.
Along with this plan, NOAA Fisheries and other agencies collect data to track the amount and type of bycatch in all U.S. fishery areas. A research plan for the Gulf of Mexico and South Atlantic fisheries is available online. The Sea Grant website has a section that provides information and archives articles about the conservation efforts of commercial shrimpers who use Bycatch Reduction Devices (BRDs) in the Gulf of Mexico and South Atlantic regions.
Research
Between 1990 and 1996, studies in the Gulf of Mexico and South Atlantic shrimp trawl fisheries looked at the amounts of fish and other sea life caught by weight. In the Gulf, about 67% of the catch was finned fish, 16% was commercial shrimp, 13% was non-commercial shrimp, and 4% was other invertebrates. In the South Atlantic, the average catch was 51% finned fish, 18% commercial shrimp, 13% non-commercial shrimp and crustaceans, and 18% non-crustacean invertebrates (by weight).
After adding different types of BRDs (Bycatch Reduction Devices) to shrimp trawl nets, fewer fish such as Spanish mackerel, weakfish, croakers, and spot were caught in the South Atlantic. In the Gulf, fewer Atlantic croakers, king mackerel, Spanish mackerel, and red snapper were caught. Protecting red snapper is a major reason the Gulf of Mexico Fishery Management Council focuses on BRDs.
From 1997 to 1998, shrimp trawls in federal waters of the Gulf of Mexico and South Atlantic regions were required to use BRDs in their nets. These devices are placed in the cod end of a shrimp trawl to help keep finfish out of the net. Since then, NOAA Fisheries has approved three BRD types for the Gulf: the Gulf Fisheye, Jones-Davis, and Fisheye BRDs. Five BRD types are approved for the South Atlantic: the Extended Funnel, Expanded Mesh, Fisheye, Gulf Fisheye, and Jones-Davis BRDs.
Research from 2003 to 2004 found that the Extended Funnel and Expanded Mesh BRDs worked well in the South Atlantic. The 12” by 5” Fisheye BRD also worked in both the South Atlantic and Gulf of Mexico. These findings may change as more research continues.