NBR Bycatch Explorer
What is bycatch?
Bycatch remains one of the largest impediments to sustainable seafood globally. The National Oceanic and Atmospheric Administration’s National Marine Fisheries Service (NOAA/NMFS) defines bycatch as “discarded catch of marine species and unobserved mortality due to a direct encounter with fishing vessels and gear” in its National Bycatch Reduction Strategy. NMFS manages bycatch and its impacts through several authorities, including the Magnuson-Stevens Fishery Conservation and Management Act (MSA), the Marine Mammal Protection Act (MMPA), the Endangered Species Act (ESA),and other domestic laws and international agreements. Each of these authorities defines bycatch differently. For example, the MSA defines bycatch as fish that are harvested in a fishery, but that are not sold or kept for personal use, and including both economic and regulatory discards. This MSA definition is similar to the definition of bycatch used by the Food and Agriculture Organization of the United Nations definition of discards. Impacts from bycatch and bycatch mortality vary across fisheries, and can have adverse biological, economic, and social consequences. Bycatch can negatively affect protected species by harming individuals, contributing to population declines, and impeding population recovery. Similarly, bycatch of fish can contribute to overfishing and impede efforts to rebuild fish stocks, resulting in negative economic and social impacts to fishermen and communities that rely on the economic benefits from a fishery or fish for food. Bycatch can also have ecological impacts by altering the availability of predators and prey that affect marine ecosystems and fishery productivity. Working with partners and stakeholders, NMFS has made significant advancements to improve the selectivity of fishing gear and modify fishing practices to reduce bycatch. However, bycatch still occurs because both target and bycatch species often inhabit the same productive areas of the ocean.
What is the National Bycatch Report?
The National Bycatch Report (NBR) is not a requirement under the MSA or other law. However, monitoring and estimating marine fisheries bycatch is an important part of NMFS’ efforts to sustain fisheries and recover protected species populations. These reports provide information on overall bycatch and, in addition to stock assessments or other data on individual stocks and fisheries, may inform fishery monitoring, science, and management priorities. In addition, the NBR is the only national-level report published by NMFS that summarizes fish, marine mammal, sea turtle, and seabird bycatch in major U.S. fisheries. NMFS released its first NBR in 2011, using data from 2005, to describe its efforts to monitor and estimate bycatch in federal commercial fisheries. NMFS released its first update to the NBR in early 2014, which included bycatch estimates for 2010. The second update to the NBR was published in early 2016 and included bycatch estimates for 2011, 2012, and 2013. NMFS published another update in 2019, and this report included bycatch estimates for 2014 and 2015. NBR bycatch estimates should not be viewed as definitive estimates, but are indicative of bycatch amounts in particular fisheries, or relative levels of bycatch across fisheries. NBR data should not be used for day-to-day monitoring or management of fisheries. The data summary and analysis methods that are used in the NBR to produce comparable bycatch estimates across fisheries and regions do not reflect individual aspects of specific fisheries. Therefore, the estimates in the NBR may not represent the best available bycatch data for management purposes.
What is the Relative Bycatch Index?
The Relative Bycatch Index (RBI) is a tool developed by Savoca et al. 2020, to compare bycatch patterns in finfish, invertebrates, seabirds, marine mammals, and sea turtles across regions, years, and gear types. The RBI takes into account the ratio of fish and invertebrate bycatch to target catch, metrics assessing the degree of seabird, sea turtle, and marine mammal bycatch, as well as the conservation status of all bycaught species. The RBI also includes a measure of the data quality provided by fisheries to the NBR. Higher RBI scores indicate larger bycatch issues. The RBI is intended to be a high-level, fishery-specific overview of bycatch in U.S. fisheries relative to one-another. US fisheries have some of the best managed and monitored fisheries worldwide with low levels of bycatch compared to international fisheries.
- Number of individual seabirds and sea turtles bycaught (individuals)
- Quantity of fish and invertebrate discarded (pounds or individuals)
- Discard rate: the ratio of fish and invertebrate discards to total catch (discarded catch + target catch), in fisheries where fish and invertebrate bycatch is given in pounds (86/95 = 91% of fisheries in the dataset)
- Number of ESA-listed species bycaught (value): The Endangered Species Act (ESA) of 1973 protects listed species from ‘take’ (i.e., harassing, harming, pursuing, hunting, or collecting) to recover their populations
- Quantity of ESA-listed fish and invertebrates discarded (pounds or individuals)
- Number of individual ESA-listed seabirds and sea turtles bycaught (individuals)
- Number of IUCN-listed species bycaught (value)
- Quantity of IUCN-listed fish and invertebrates discarded (pounds or individuals)
- Number of individual IUCN-listed seabirds and sea turtles bycaught (individuals)
- MMPA category: (category) I – frequent interactions with marine mammals; II – occasional interactions with marine mammals; III – remote likelihood of, or no known, interactions with marine mammals
- Average Coefficient of Variation (metric)
- Fishery Tier Classification: (category) 0 – No bycatch data collection programs; 1 – Bycatch estimates based on outdated or unreliable information and no observer data; 2 – Bycatch estimates included, but observer programs inadequate; 3 - Bycatch estimates based on reliable observer data or recent logbook data but limited observer coverage and varied sampling designs; 4 – Bycatch estimates based on reliable observer program data collected on an annual basis for at least the past five years, negligible program design deficiencies
Savoca, M. S., Brodie, S., Welch, H., Hoover, A., Benaka, L. R., Bograd, S. J., & Hazen, E. L. (2020). Comprehensive bycatch assessment in US fisheries for prioritizing management. Nature Sustainability, 1-9.
This project is a collaboration between California Sea Grant, UC Santa Cruz, and NOAA’s Offices of Science and Technology and the Southwest Fisheries Science Center.
Funding for this project has been provided by NOAA/NMFS FIS-NOP grant to the Southwest Fisheries Science Center with additional support from California Sea Grant to fund Dr. Savoca.