![Shrimp+Onboard[1]](https://geoshell.com/wp-content/uploads/2025/12/ShrimpOnboard1-1024x768-480x250.webp "Shrimp+Onboard[1]")
Three types of bycatch reduction devices (BRD) [turtle excluder device (TED), square mesh codend (SMC) and fisheye (FE)] were tested aboard shrimp trawl vessels. Differences in catch from nets equipped with a BRD on one side and a standard net on the other were compared for each of the three BRD’s. Use of the TED […]
![JohnFord.spermwhale.depredation-scaled[1]](https://geoshell.com/wp-content/uploads/2025/12/JohnFord.spermwhale.depredation-scaled1-1024x679-480x250.jpg "JohnFord.spermwhale.depredation-scaled[1]")
Two devices were designed to prevent odontocetes from depredating caught fish and putting themselves at-risk of becoming bycatch. One device used physical deterrence by shouding the fish with a barrier and the other used psychological deterrence by utilizing prior negative experiences of temporary entanglement in fishing gear. Both devices fit on a branchline at a […]
![Photo-1-1-scaled[1]](https://geoshell.com/wp-content/uploads/2025/12/Photo-1-1-scaled1-1024x683-480x250.jpg "Photo-1-1-scaled[1]")
Acoustic pingers reduced the bycatch of the Common Murre (Uria aalge) in the Puget Sound salmon drift gillnet fishery, but they did not reduce bycatch of the rhinoceros auklet (Cerorhinca monocerata). Reduction of target species catch was not significant. White gillnet mesh panels in the upper portion of the net reduce the bycatch of seabirds […]
![AP21153511606682[1]](https://geoshell.com/wp-content/uploads/2025/12/AP211535116066821-1024x682-480x250.jpg "AP21153511606682[1]")
This study investigated whether North Atlantic right whale behavior changes, in terms of response distance, to changing visual characteristics of rope mimics in their path. 20 ft rope mimics were made from two 10 ft sections of rigid PVC pipe, with an approximate diameter of 1 inch. The rope mimics were weighted and attached to […]
![07-toothfish-fig2_afma.1200x630[1]](https://geoshell.com/wp-content/uploads/2025/12/07-toothfish-fig2_afma.1200x6301-1024x538-480x250.jpg "07-toothfish-fig2_afma.1200x630[1]")
A modified longline system with a net sleeve and weight on the secondary vertical line was tested in the Chilean Patagonian toothfish fishery. A net sleeve that deploys to cover the fish/hook when hauled and a weight were attached to the vertical hook line. The net sleeve significantly reduced depredation of fish by killer whales […]
![North-Pacific-Spiny-Dogfish-063[1]](https://geoshell.com/wp-content/uploads/2025/12/North-Pacific-Spiny-Dogfish-0631-e1773223803320-1024x623-480x250.jpg "North-Pacific-Spiny-Dogfish-063[1]")
A rare-earth metal alloy (cerium/lanthanide) was tested to determine if it would reduce bycatch of spiny lobster on longlines and rod and reel gear in the Gulf of Maine. Laboratory and field trials showed no significant reduction in dogfish catch.
Over time, noxious bait, consisting of dead steelhead containing lithium chloride, did not prevent California sea lion (Zalophus californianus) predation of Washington steelhead trout (Salmo gairdneri). Acoustic harassment devices worked only for a short time in reducing California sea lion depredation before sea lions began to habituate to sounds.
School shark (Galeorhinus galeus) liver oil dripped behind fishing vessels in the northern New Zealand snapper (Pagrus auratus) longline fishery reduced seabird numbers and dives on baits when compared to canola oil and seawater control treatments. The shark liver oil did not affect the number of target snapper, gurnard (Chelidonicthys kumu), kaha-wai (Arripis trutta), or […]
A Double-FAD design was tested for it’s ability to mitigate the incidental capture of bigeye tuna in purse fisheries of the Western and Central Pacific Ocean. The design consisted of two separate FADs with underwater light stimuli attached. The number of animals caught was not large enough to conduct statistical analyses, but based on the […]
Gillnets with three difference mesh sizes (2 7/8″, 3″ and 4″) were modified to use 200 lbs/200 yard lead line and 11 oz buoyancy floats (versus 50lbs/200 yard lead line and 3 oz floats) to increase the tension in the net. Catch rates of Atlantic sharpnose and bonnethead sharks were significantly lower in the 4″ […]
In the Indian Ocean tuna gillnet fisheries, cetacean bycatch is very high, but it is understudied and poorly understood. This paper investigates the issue and makes specific recommendations to strengthen knowledge and management: improve catch and bycatch reporting, increase research and analyses of cetaceans in the region in order to assess bycatch, revise the conservation […]
A meta-analysis of online publications revealed only one technique to be effective as a bycatch reduction device in longline fisheries, which involves raising demersal longlines off the seafloor using flotation. Other techniques as BRDs include monofilament leaders which, like floating demersal longlines, are suggested as promising approaches for further evaluation. Although not effective as a […]
Field experiments were conducted to determine behavioral responses of minke whales to experimental ropes and buoys made up of different colors, simulating those used in crab and whelk fishing gear. Trials were conducted with yellow, orange, green, blue, white and black ropes. Visual and acoustic monitoring was used to assess behavioral responses of whales to […]
Entanglement in commercial fishing ropes threatens the recovery of the North Atlantic right whale (Eubalaena glacialis), a species largely restricted to waters off of eastern North America. In recent years, serious entanglements have been increasing, and mortality from conflicts with fishing operations exceeds US legal mandates, with 83% of the population showing incidence of scarring […]