Bycatch Reduction Engineering Program 2021 Report to Congress

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Funding Bycatch Reduction

Bycatch Reduction Engineering Program Annual Report to Congress, 2021 (PDF, 14 pages)

Bycatch occurs when fishermen discard catch of marine species, or when resources like marine mammals, seabirds, or protected fish are harmed or killed by fishing gear. Reducing bycatch in fisheries can improve the recovery of protected species and has positive biological, economic, and social impacts. The National Oceanic and Atmospheric Administration’s National Marine Fisheries Service (NMFS) has long been committed to reducing bycatch through management, monitoring, research, enforcement, education, and communication efforts, as described in the National Bycatch Reduction Strategy.

The Bycatch Reduction Engineering Program (BREP), authorized under Section 316 of the Magnuson-Stevens Fishery Conservation and Management Act, supports technological solutions and conservation engineering practices. These solutions and practices minimize bycatch and bycatch mortality in managed fisheries. From FY 2012 through 2021, NMFS has supported 159 BREP awards totaling approximately $23 million to external partners, including state governments, academia, and the fishing industry. The awards are geographically diverse and address four different priorities: reducing protected species bycatch, developing innovative technologies, improving fishing practices, and reducing post-release mortality. The vast majority of BREP projects involve the fishing industry. This ensures that these key partners are engaged in developing solutions to address bycatch issues. The results of many BREP-funded projects inform new regulations or other management actions.

Highlights & Outcomes

This report summarizes the outcomes of 12 BREP awards funded by NMFS in FY 2021, totaling more than $2.2 million. This report shows that bycatch reduction research, as with any research, can result in a range of outcomes. Finding technological solutions to bycatch problems is a multiyear and multidisciplinary endeavor. It requires technical expertise, collaboration with fishermen, and effective communication with managers and fisheries partners.

2021 Funding by Priority

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Reducing Protected Species Bycatch

One 2021 BREP project addressed bycatch of protected species, such as Atlantic sturgeon.
This project took place in the mid-Atlantic and southern New England.

Delaware State University ($233,676): 

Bycatch reduction of modified large mesh sink-gillnets in the Atlantic monkfish fishery

Gillnets have been used in commercial fisheries in the mid-Atlantic and New England regions
for well over a century. Their relative ease of use, low cost, and high catch rates are favored by the commercial fishing industry. Although gillnets are generally selective for target species, their use often leads to bycatch of non-target species. This project focused on comparing catch rates of monkfish, spiny dogfish, and winter skate as well as self-reported encounter rates of Atlantic sturgeon (listed under the Endangered Species Act) in industry standard and experimental gillnets fished in the large mesh sink-gillnet fishery. Working collaboratively with eight commercial harvesters in the mid-Atlantic and southern New England regions, the researchers conducted field trials under “real world” conditions. These trials began during fall 2023 and concluded in spring 2024. Preliminary findings based on limited sample sizes suggest that these modified nets reduce Atlantic sturgeon bycatch with only a small decrease in the catch of targeted species. By working with the industry, this project aimed to affect changes in fisheries practices that foster the conservation and recovery of protected species and allow for sustainable harvest of the nation’s marine resources.

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Innovative Technology

In 2021, seven BREP-funded projects along the West and East coasts, particularly in the Gulf of Maine and in Massachusetts, focused on innovative technology to address bycatch issues. This included testing ropeless gear designs, biodegradable fish aggregation devices, and artificial illumination of fishing gear.

Pfleger Institute of Environmental Research ($188,416): 

Reducing longline bycatch using artificial baits off the Hawaiian Islands

This collaborative study deployed artificial baits in a pelagic longline fishery to explore shark
bycatch reduction. Experimental trials were performed in the Hawaiian short-line fishery. This
platform targets bigeye tuna and allows for cost effective testing of pelagic longline gear on a smaller scale. Assessments of catch performance and selectivity were conducted using both natural and illuminated artificial baits during the same short-line set. The study tested whether artificial baits can reduce shark bycatch, and whether natural and artificial baits share similar target catch rates. The findings suggest that artificial baits can be used to avoid sharks as well as other non-retained catch, but they result in slightly lower target catch rates. These results suggest that future work should focus on improving the performance of artificial baits prior to scaling to more industrialized applications. Findings from this work are being prepared for publication in a scientific journal and are being expanded upon in a 2023 BREP-funded study. The 2023 study examines shark avoidance strategies on a larger scale.

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International Pacific Halibut Commission ($99,700): 

Gear-based approaches to catch protection as a means for minimizing whale depredation in longline fisheries

Removal of captured fish from fishing gear, known as depredation, is a growing problem among many hook and-line fisheries worldwide. In the North Pacific Ocean, toothed whales such as orca and sperm whales are involved in depredation behavior in Pacific halibut, sablefish, and Greenland turbot longline fisheries. This behavior presents challenges to
fishermen, fisheries managers, and whales. Fishermen have to deal with loss of catch as well as reduced efficiency. Fisheries managers are challenged with accurate removal estimation. Whales are faced with injury risk, disruption of social structures, and developing artificial reliance on non-primary food sources that can be affected by fishery dynamics.

BREP funding supported the organization of an international workshop for identifying current
state-of-the-art approaches to protecting longline-caught fish. The focus was on low-cost,
easy-to-adopt gear modifications that securely retain catch, while breaking the “reward cycle”
underpinning depredation behavior.

The project incorporated the top catch protection gear designs from the workshop into functional prototypes and conducted field-testing in longline sea trials. The two selected catch protection devices were an underwater shuttle and branch gear with a sliding shroud system. The shuttle slides down the groundline until it nears the seabed, where it mechanically unhooks fish and entrains them within the device. Then it securely brings them to the surface. The branch gear modifies traditional longline fishing, incorporating hooks that are attached to a side branch and a shroud that slides down to cover the branch, protecting the hooks and catch as the gear is hauled to the surface. Both types of gear were successfully tested on a typical longline vessel to investigate the logistics of setting, fishing,
and hauling. They were also tested to determine their basic performance on catch rates and
fish sizes compared to traditional gear. Video monitoring of gear performance above water and underwater provided detailed information on all parts of the deployment and capture process. The shuttle proved to be a safe and effective gear type. It showed the most promise for entraining comparable quantities, sizes, and types of fish as control sets, and warrants further testing in the presence of depredating whales.

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New England Aquarium ($208,234): 

Innovative technology to understand the impacts of fisheries gear entanglement on endangered leatherback sea turtles

Bycatch in fishing gear is the leading cause of sea turtle declines worldwide, but there is limited information on the outcomes of sea turtles that are freed from fishing gear. In this study, researchers conducted health assessments and post-release monitoring of leatherback sea turtles that are disentangled from the buoy lines of pot/trap fishing gear in
Massachusetts. The turtles were given a physical examination by veterinarians and information was collected on their condition, including heart and respiratory rates, body temperature, and blood data. Turtles were released with a 30-day survivorship popup archival tag for short-term monitoring, and a 7-year+ acoustic tag for long-term monitoring. The researchers also tested an alternative approach for short term monitoring (24-48 hours
post-release) by developing a custom data logger package that includes an accelerometer,
depth and temperature data logger, and digital camera logger. Data logger packages
were deployed on feeding, free swimming leatherbacks as well as disentangled leatherbacks
to compare behavior data. The study provides the first empirical validation of NMFS’ predictions of post-interaction mortality criteria that are routinely used in estimating mortality rates for vertical line fisheries. The research is ongoing, but preliminary results suggest high survivorship of disentangled turtles in good condition. But more data are needed for serious injuries, such as severe flipper trauma or moribund condition. The short term, recoverable data logger packages are a promising and cost effective alternative to satellite tags for acute monitoring of lethal/sublethal impacts of fisheries interactions.

International Seafood Sustainability Foundation, Inc. ($168,962): 

Testing the use of biodegradable fish aggregating devices in the Pacific Ocean

The U.S. tropical tuna purse seine fleet, which consists of 16 vessels, is trialing biodegradable Innovative Technology fish aggregating devices (FADs). Biodegradable FADs are made primarily from organic bamboo and cotton and are designed to break down naturally in the ocean. This reduces the threat of ghost fishing (i.e., when derelict gear continues to catch marine life). This also reduces damage to vulnerable marine habitats. Through this test 132 biodegradable FADs have been deployed. They are being monitored for their performance by the crew, together with scientists from the International Seafood Sustainability Foundation and The Pacific Community. These FADs have demonstrated the capability to yield substantial tuna catches of up to 55 tons so far. They have also proven to attract schools of tuna as effectively as traditional FADs. The researchers plan to conduct a more comprehensive analysis of the effectiveness of these innovative devices once data from the total deployment of 236 FADs have been collected.

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LiftLabs, Inc. ($185,590):

Development of an interoperable ropeless system in collaboration with fishermen

The critically endangered North Atlantic right whale faces multiple threats, one of which is entanglement in trap and pot fishing gear. This project focused on cost-effective ropeless solutions to promote the coexistence of these whales and trap and pot fisheries. The project team developed a flexible ropeless system accommodating various acoustics options. The options ranged in price from $150 to $4,000, to cater to both high-profit and low-profit fisheries. This system is designed for reliable recovery and quick redeployment, providing invaluable benefits to fishery participants and marine conservation. Furthermore, with rigorous testing, collaboration with industry experts, and a resulting 40 percent cost reduction, this ropeless system is on track to cost less than $500. If successful this would be a significant cost savings for ropeless systems, which can cost more than $4,000 per unit.

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Sea Mammal Education Learning Technology Society ($246,458):

Advancing ropeless/on-demand fishing technology in the Gulf of Maine

The Sea Mammal Education Learning Technology Society™ (SMELTS™) has been working with commercial fishing captains to advance the use of on-demand, or ropeless, fishing gear for American lobster and the Jonah crab fishery. The SMELTS™ design uses acoustics to activate a valve on the seafloor that allows compressed air to enter a lift-bag, also known as a balloon. It automatically lifts gear back to the surface for fishermen to recover their catch.
The lift-bag is then deflated and gear is ready to be reset, completely removing the need for
a line.

In winter 2022, the SMELTS™ gear was one of only two ondemand systems permitted by an exempted fishing permit to be used in the seasonal fisheries closure in Massachusetts. This was where the critically endangered North Atlantic right whales would forage and rest above commercial lobster gear with no end-lines. It is an important step for NOAA and our partners in our work to save North Atlantic right whales from extinction as a result of bycatch in bottom-set fixed-gear fisheries.

SMELTS™ has been advancing the shipboard technology in commercial fishing vessels by leading the installation of acoustic transducers directly into a commercial ship’s hull. This is done for reliable acoustic communications and ease of use. SMELTS™, partnering with Teems Fish Monitoring, has developed the Skipper Scan—a unique system that automatically marks gear on a chart while inventorying and cataloging gear using Radio Frequency Identification tags and scanners with GPS positioning.

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Pacific States Marine Fisheries Commission ($245,797): 

Artificial illumination of trawl gear components to reduce Pacific halibut bycatch in West Coast and Alaska bottom trawl fisheries

Pacific halibut are a prohibited species in trawl fisheries. In the West Coast groundfish bottom trawl fishery, management regulations have recently changed. Fishermen are now allowed to use high-rise hooded trawls in areas that previously only permitted low-rise non-hooded trawls. Previous research has shown that artificial illumination on the upper bridles of a low-rise non-hooded trawl can reduce Pacific halibut bycatch. This study examined whether the same effect could be achieved when applying artificial illumination to a high-rise hooded trawl. When compared to a nonilluminated high-rise trawl, results showed the illuminated high-rise trawl on average caught 56 percent fewer Pacific halibut. A slight though not statistically significant, decrease in the average catch of target species was also noted in the illuminated trawl. This study’s findings suggest that artificial illumination may alter the behavior and vertical distribution of Pacific halibut when entering trawls. The findings also suggest that trawl design may affect the ability of artificial illumination to reduce their bycatch. This research has provided fishermen with valuable information in considering trawl design use in areas that encounter Pacific halibut. 

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Reducing Post-Release Mortality

In 2021, two BREP-funded projects explored how to reduce post-release mortality. One project focused on reducing post-release mortality of sharks and rays in drifting tuna longline fisheries in the Pacific Islands. The other project quantified porbeagle shark post-release mortality in the Northeast United States. Results from this project could inform NMFS’ data on shark and ray survival rates as well as support shark and ray fisheries policy.

New England Aquarium ($191,897): 

Quantifying porbeagle shark post release mortality and bycatch susceptibility in the Northeast U.S. bottom trawl fishery

The porbeagle shark is overfished in the Northwest Atlantic, with stock biomass estimated at only 44 percent of the species’ abundance in the 1960s. Landing regulations have since reduced fishing mortality for these sharks, but the post-release mortality (PRM) of porbeagle continues to occur in commercial fisheries. Recovery of this species may be predicated upon the magnitude of PRM and require additional management measures to mitigate this source of mortality. This project evaluates porbeagle PRM in the Northeast U.S. bottom trawl fishery. This fishery has one of the highest discard rates for this species, but it does not have any available PRM estimates to gauge the fishery impact on porbeagle.

Through industry partnerships, this project trained fishermen to collect capture data and satellite tagged incidentally captured sharks on regularly permitted trips. Data generated from these 34 tagged sharks are being used by project investigators to determine post-release animal movement and fate. A preliminary PRM rate of 29.2 percent has been observed thus far based on raw proportions of live and dead animals. However the final fishery-scale estimate of PRM will also account for variable mortality rates across fishing conditions and practices. For example, this project’s preliminary evaluation of fate data suggests that mortality rates increase with extended tow durations and worsening animal conditions. Identifying capture-related factors driving mortality in the fishery, such as tow duration, can
also inform best fishing practice frameworks to mitigate PRM. This project also plans to examine the proportion of time sharks spend within the range of trawl fishing gear depths to develop bycatch avoidance strategies as a complementary mechanism for reducing mortality. This project is nearing completion, with only six tags remaining for fishing partners to deploy.

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Eric Gilman, LLC ($53,200): 

A Bayesian synthesis of at-vessel mortality rates of elasmobranchs taken in pelagic longline fisheries to support evidence-based bycatch mitigation policy

Top and middle trophic level predators, such as sharks and rays, are vital contributors to ocean health. This helps make them the focus of conservation efforts to mitigate exposure to fishing and other hazards. These efforts are imperative because small changes in mortality can greatly influence population growth. A key component of total fishing mortality is at vessel mortality (AVM), which is the amount of catch that is dead upon retrieval of gear. Accurately estimating the sources of mortality, like AVM, is essential for creating robust assessments of the ecological effects of fishing, such as thorough quantitative stock assessments, population viability models, and multispecies ecosystem models.

This project assembled a database of 61 shark and ray species, estimating their AVM rates in pelagic longline fishing gear through a global meta-synthesis, or a quantitative, model-based assessment. Phylogeny, or evolutionary history, was found to be a significant predictor of AVM. It suggests that species sharing a high degree of evolutionary history may as a result be ecologically similar and have a high degree of shared traits that explain their AVM rates. Adjusting for phylogenetic dependence therefore produces more robust estimates of AVM rates for a specific species.

AVM rates ranged from 5 percent for the pelagic stingray to 58 percent for the pelagic thresher shark. The pelagic stingray is the most common ray species captured in tuna longline fisheries and categorized as “least concern” by the International Union for Conservation of Nature. The pelagic thresher shark is categorized as “endangered” by the International Union for Conservation of Nature.

This database of estimated AVM rates is useful for giving evidence informed support to shark and ray fisheries policy. Measures that reduce catch, and hence AVM levels, are appropriate for species with higher AVM rates. These measures include input controls on fishing effort, output controls such as bycatch quotas, and gear technology to increase selectivity. This BREP-funded study, which was published in the journal Scientific Reports, identifies effective approaches to reduce the capture mortality of sharks and rays in drifting tuna longline fisheries that should be considered by the relevant management organizations.

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Improving Fishing Practices

In 2021, two BREP-funded projects explored how to improve fishing practices with commercial longline vessels in the Gulf of Mexico and on the West Coast.

Mote Marine Laboratory ($188,995): 

Impacts of hook size modifications on catch and bycatch rates in the Gulf of Mexico bottom longline reef fish fishery

The Center for Fisheries Electronic Monitoring at Mote partnered with two eastern Gulf of Mexico commercial bottom longline vessels with electronic monitoring (EM) systems to evaluate the impact of different hook sizes (13/0-15/0) on discard rates and overall catch. They also used vessels to assess short term survival of discards. For the study on hook sizes, they provided the captains with 10,000 hooks, as well as 4,000 painted and unpainted longline clips for video reviewers to differentiate between the two hook sizes among individual fish. A total of 168 hauls from 17 trips generated more than 12,600 catch events that were used to analyze changes in catch rates, specifically for the primary target species, red grouper. Results showed that the discard rate of red grouper decreased significantly (by as much as 70 percent) with the larger 15/0 hooks. However, these hooks also led to a projected small decrease in retained catch. In addition, the study proved that EM can be used successfully as a platform to accurately address the impacts of gear modifications on catch and discards, and can be repeated to test a wide variety of gear changes other than hook sizes. Examples of other gear changes include bait types and leader lengths.

For the study on short-term survival of discards, EM camera views were improved with the addition of stern boom-mounted cameras to achieve better documentation of short-term
survival of individual discarded catch. They included discarded fish post-release status—an
important component that typical EM systems leave out.

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Pacific States Marine Fisheries Commission ($157,897): 

Testing modified circle hooks to reduce yelloweye rockfish bycatch in the West Coast directed Pacific halibut longline fishery

In Pacific halibut longline fisheries in the eastern North Pacific Ocean, bycatch of yelloweye rockfish is a concern because their stock status along the U.S. West Coast is “rebuilding” from “overfished” status. The southeast Alaska stock has shown an approximate 60 percent decline since at least 1994 and through 2015 when it stabilized. The Canadian stock was recently declared “threatened.” In this study, researchers evaluated how size 16/0 and 18/0 circle hooks affect the catch efficiency of Pacific halibut and yelloweye rockfish. They also examined the catch efficiency of these hooks when modified with a 3.1 mm stainless steel wire appendage—extending 7.6 cm from their shank at either a 45 ° or 90 ° angle.

Results showed that hook size did not significantly affect the catch efficiency of Pacific halibut or yelloweye rockfish. However, hooks with a 45o appendage angle caught significantly fewer yelloweye rockfish than hooks without an appendage, irrespective of hook size. The appendage angle did not affect the catch efficiency of Pacific halibut. Results from this study suggest that hook appendages have potential use in reducing catch rates on yelloweye rockfish in Pacific halibut longline fisheries. This may lead to increased fishing opportunities and more efficient Pacific halibut fisheries, and help contribute to the rebuilding process of yelloweye rockfish.

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