Bycatch Data Reporting from Observer Programs Database
In 2025, NOAA Fisheries made significant progress towards building the Bycatch Data Reporting from Observer Programs (Bycatch DROP) database by establishing partnerships with additional NOAA Fisheries bycatch data providers, generating procedures for the database to track changes to fisheries names and bycatch estimation methods, and developing business rules for assessing trends in fisheries bycatch over time consistently.
Background
Ensuring the sustainability of marine resources for future generations is the primary mission of the National Oceanic and Atmospheric Administration’s National Marine Fisheries Service (NOAA Fisheries). Bycatch, or the unwanted species or individuals caught during fishing operations (Hall 1996), can reduce fishing efficiency and profits, contribute to overfishing, and harm endangered and threatened protected species. For the purpose of this work, we define bycatch as the portion of the catch that is discarded at sea because it has low economic value or because fishery regulations prohibit retention, e.g., minimum landing sizes (Hall 1996). Bycatch can be bony fish, but also includes protected species such as dolphins, whales, seals, sea turtles, sharks, rays, corals, sponges, and seabirds that become hooked or entangled in fishing gear. Unwanted catch is an issue both ecologically and economically, and occurs in both commercial and recreational fisheries. Animals that are discarded often die and cannot reproduce, impacting marine ecosystems. Bycatch can slow the rebuilding of overfished stocks, increase the risk of extinction for protected species, and degrade marine habitats, potentially hurting ecosystem services. Bycatch can also have negative economic and social impacts on fishers and their communities by leading to early fishery closures, or impacting consumer preferences. Ecologically, bycatch can change the availability of prey and remove top predators, which affects the productivity of marine ecosystems and fisheries.
A multitude of factors can influence the spatiotemporal trends in bycatch for a particular fishery, including gear characteristics, fisher behavior, biological traits of species, species interactions, and environmental variables (Hall et al. 2000). However, the relative importance of these factors to realized annual bycatch estimates will vary by fishery and ecoregion, which influences the success of management measures to reduce bycatch. The first step in reducing harmful bycatch is accurate characterization of bycatch levels for stocks, species, and species groups (if higher-resolution taxonomic information is not available) through space and time. Understanding the amounts and types of bycatch in our nation’s fisheries is also an important component of ecosystem-based fisheries management, which seeks to account for the complex connections among organisms in management frameworks, including humans and their environment. Estimation of fish and protected species interaction rates with commercial fisheries depends on independent data provided by fishery observers (who are professionally trained biologists deployed on commercial fishing vessels, and in some cases at processing plants), or electronic monitoring systems that include video monitoring of fishing activities. Observers collect both quantity and composition information on catch and bycatch, as well as information on fish discards (e.g., released alive vs. dead) and condition of protected species bycatch (e.g., location of entanglement and/or hooking, condition of animal upon release). Biological samples, gear type, environmental conditions, economic data, and other information useful for stock assessments are also collected by observers. While fishers participating in federally-managed fisheries are generally required to self-report all fishing interactions, observer data are considered the most reliable source of information on bycatch because logbook records are often incomplete, and underreporting of fish and protected species bycatch can be significant (Emery et al. 2019, Brown et al. 2021).
NOAA Fisheries is committed to continuing to reduce and minimize bycatch now and into the future, and is guided by existing legislation (Table 1). Reliable fisheries monitoring data is essential for reducing wasteful bycatch while protecting ecosystem health, enabling fisheries managers to measure progress and make informed changes to fisheries regulations that support both conservation and sustainable fishing. Fish and marine mammal bycatch are accounted for in stock assessments that determine whether fish stocks are overfished or overfishing is occurring, and whether marine mammal stocks are strategic (meaning the level of direct human-caused mortality exceeds the potential biological removal, or the stock is declining and likely to be listed as threatened under the Endangered Species Act (ESA), or the stock is already listed as threatened or endangered under the ESA, or is designated as depleted under the MMPA). Data on the bycatch of sea turtles, seabirds, marine mammals, and other protected groups in commercial and recreational fisheries is essential for status determinations under the ESA.
Table 1: Legislative requirements to reduce bycatch in the U.S.
Legislation | Authority Concerning Bycatch |
Magnuson-Stevens Fishery Conservation and Management Act (MSA) 16 U.S.C. § 1801 et seq. | The MSA is the primary law that governs marine fisheries management in U.S. federal waters, and fosters the long-term biological and economic sustainability of marine fisheries. This legislation includes ten National Standards that must be followed in any fishery management plan to ensure sustainable and responsible fishery management. National Standard 9 requires that conservation and management measures shall, to the extent practicable, minimize bycatch and, to the extent that bycatch cannot be avoided, minimize the mortality of such bycatch. |
Marine Mammal Protection Act (MMPA) 16 U.S.C. §§ 1361–1423h | The MMPA protects all marine mammals in waters or on lands under U.S. jurisdiction, with a goal of reducing incidental mortality and serious injury of marine mammals occurring in the course of commercial fishing operations to insignificant levels. The MMPA requires NOAA Fisheries to publish an annual list of commercial fisheries and classify each fishery based on whether it has frequent (Category I), occasional (Category II), or remote likelihood (Category III) of incidental mortality and serious injury of marine mammals. |
Endangered Species Act (ESA) 16 U.S.C. §§ 1531–1544 | The ESA protects species listed as threatened or endangered. All six species of sea turtles found in U.S. waters are listed and protected under the ESA (green, hawksbill, kemp’s ridley, leatherback, loggerhead, olive ridley). NMFS has the responsibility to implement programs to conserve marine life listed as endangered or threatened. Bycatch in fishing gear is the primary anthropogenic source of sea turtle injury and mortality in U.S. waters. Section 9 of the ESA prohibits the take (defined to include harassing, harming, pursuing, hunting, shooting, wounding, killing, trapping, capturing, or collecting or attempting to engage in any such conduct), including incidental take, of endangered animals. |
Migratory Bird Treaty Act (MBTA) 16 U.S.C. §§ 703–712 | The MBTA prohibits the take (including killing, capturing, selling, trading, and transport) of protected migratory bird species without prior authorization by the U.S. Fish and Wildlife Service (USFWS). Most of the 312 species of seabirds are protected by the Migratory Bird Treaty Act, and some are endangered or threatened under the ESA. |
Bycatch DROP Database Update for 2025 - Timeliness, Transparency, and Trends
NOAA Fisheries has undertaken a multi-year project to modernize the Bycatch DROP database by improving timeliness of data updates, transparency of estimation methods, and adding trend analyses. The Bycatch DROP database is being built on the NOAA Fisheries One Stop Shop (FOSS), which already hosts data on commercial and recreational landings, foreign trade, US ports, processed products, and more.
Over the past year, NOAA Fisheries has improved processes and procedures for importing fish bycatch estimates by fishery from the Pacific Islands Fisheries Science Center (PIFSC) bycatch database, the Northwest Fisheries Science Center (NWFSC) Fishery Resource Analysis and Monitoring Division (FRAM) Data Warehouse, the Alaska Catch Accounting System, and the Greater Atlantic Regional Fisheries Office (GARFO) Catch Accounting and Monitoring System (CAMS). Of these, only the PIFSC database contains bycatch estimates for marine mammals, sea turtles, and seabirds. For the other regions, we worked with their protected species bycatch teams to upload files of their data to our Bycatch DROP github repository, which automatically tracks all changes made to data files. The Southeast Fisheries Science Center (SEFSC) submitted post-2016 data to the Bycatch DROP github repository for three fisheries, with more expected in 2026.
In 2025, we compiled metadata on bycatch estimation methods and associated scientific publications from our published technical report summarizing all of the bycatch estimation methods used to produce bycatch estimates for federally managed fisheries (Chan and Benaka 2024). This metadata on methods has been integrated into the Bycatch DROP database, and we are working through quality control procedures and establishing workflows for annual updates. Once the database is public, users will be able to download reports of bycatch estimates that include descriptions of estimation methodology and references.
Figure 1: Scatterplot showing the presence or absence of bycatch data per year from select fisheries in each NOAA Fisheries region (AK - Alaska, NE - Northeast, PI - Pacific Islands, SE - Southeast, WC - West Coast).
Finally, when appropriate, we will also add analyses of bycatch trends to the data portal, and identify appropriate bycatch estimates for comparison across years. Because the Bycatch DROP database is not yet in a production environment (i.e., live for public users), NOAA Fisheries has not developed any summaries of fishery-specific bycatch levels and trends. We are assembling our national team of coauthors, and developing business rules and statistical methodology for a scientific publication on bycatch trends, as resources allow. Monitoring changes in bycatch over time on a national scale could provide an indication of how well NOAA Fisheries is meeting the bycatch reduction goals of the MSA, ESA, MMPA, and MBTA. The results of trend analyses could also aid national prioritization of research and bycatch reduction efforts.
High Priority Bycatch DROP Data Gaps
In 2026, the Bycatch DROP team continues to work closely with bycatch analysts at the SEFSC to integrate their new bycatch data with previous submissions from 2015 and earlier. Incorporating protected species bycatch estimates from the West Coast, including salmon, is another high priority data gap. We will continue refining methodology to automatically integrate new data in Bycatch DROP, and track changes to fisheries structure and bycatch estimation methods through time. We also plan to organize discussions with regional experts specializing in fish, marine mammal, sea turtle, and seabird assessments to ensure the Bycatch DROP database consistently serves the best scientific information available on annual fishery bycatch levels and trends.
Figure 2: Balloon plot showing the number of unique estimation methodologies used to produce bycatch estimates for fish, seabirds, sea turtles, protected resources (PR) fish, and marine mammals in each NOAA Fisheries Region over time.
Previous National Bycatch Reports and Updates
The National Bycatch Report webpage includes the 2011 U.S. National Bycatch Report, as well as three updates to the report and various supplemental tables.
References
Brown, C. J., Desbiens, A., Campbell, M. D., Game, E. T., Gilman, E., Hamilton, R. J., Heberer, C., Itano, D., & Pollock, K. (2021). Electronic monitoring for improved accountability in western Pacific tuna longline fisheries. Marine Policy, 132. https://doi.org/10.1016/j.marpol.2021.104664
Chan, A.N. and Benaka, L.R., 2024. Bycatch Estimation Methodologies Used for the US National Bycatch Report Database. NOAA Tech. Memo. NMFS-F/SPO-252.
Emery, T. J., Noriega, R., Williams, A. J., & Larcombe, J. (2019). Changes in logbook reporting by commercial fishers following the implementation of electronic monitoring in Australian Commonwealth fisheries. Marine Policy, 104. https://doi.org/10.1016/j.marpol.2019.01.018
Hall, M.A., 1996. On bycatches. Reviews in fish biology and fisheries, 6(3), pp.319-352.
Hall, M.A., Alverson, D.L. and Metuzals, K.I., 2000. By-catch: problems and solutions. Marine pollution bulletin, 41(1-6), pp.204-219.
National Marine Fisheries Service. 2011. U.S. National Bycatch Report [ W. A. Karp, L. L. Desfosse, S. G. Brooke, Editors ]. U.S. Dep. Commer., NOAA Tech. Memo. NMFS-F/SPO-117E, 508 p.