Management Categories

    Management information in the BMIS provides context and rationale for the development of bycatch conservation and management measures (see Regulations). We have devised categories for references, to make searching management information easier.

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    At-Vessel and Post-Release Mortality

    Fisheries bycatch mortality includes observable (at-vessel) and cryptic mortality, with post-release mortality a component of the latter. Research in this category examines factors affecting at-vessel mortality and post-release mortality, to both improve the accuracy of bycatch estimates (which feed into population status assessments and hence management measures), and to develop techniques and strategies to reduce capture mortality.

    Bycatch Threats and Interaction Rates

    Literature in this category examines threats to bycatch species from human activities, including fisheries, and looks for patterns in these interactions.

    Studies considering bycatch threats often analyse interactions between fisheries and bycatch species, and identify aspects to target for threat mitigation. These aspects may include spatial areas in which bycatch threats are greatest (‘hotspots’) [e.g. 2]. Some studies prioritise actions to reduce identified threats [e.g. 3]. Papers may discuss threats in terms of percentages of populations affected, such as how many seabirds are killed in longline fisheries each year [e.g. 4]. Oliver et al. (2015)[5] address broad-scale patterns of elasmobranch bycatch in commercial longline, trawl, purse- seine and gillnet fisheries and Bugoni et al. (2008)[6] explore seabird bycatch rates in the south-western Atlantic Ocean...


    This category is predominantly concerned with issues surrounding compliance with RFMO conservation and management measures, such as observer coverage, at-port inspection, crew training and on-board bycatch data collection and quality.

    Data Availability and Collection

    Literature included here covers reviews of data availability and collection. Data reviews aim to summarise data availability and identify gaps. Reviews are conducted for different purposes, e.g., identifying gaps in data collection so that additional fields might be added to observer forms, or identifying whether there is sufficient catch and effort data across spatial areas or through time so that stock assessments can be conducted.

    Data Harmonisation

    Harmonisation of bycatch data (i.e., required data fields for fishing trips/sets) collected across tuna RFMOs is progressing through initiatives arising from the Joint tRFMO Expert Technical Working Group on Bycatch. Data harmonisation will allow for more comprehensive reporting on the status of bycatch species, assist with the identification of factors that cause or increase bycatch, and evaluate the performance of mitigation methods [1]. At the same time, improvements in the quality of the data collected should help stock assessments and other functions of RFMOs [1]. It is anticipated that reports, interim data tables, and agreed outcomes will be forthcoming. This is the type of literature included in this category, as well as more general literature.


    E-monitoring technologies are being trialled onboard vessels in some fisheries for their potential benefits in improving management, reporting, and cost efficiencies [e.g. 1]. They have the potential to ensure data collections are timely, accurate, adaptable to emerging needs, and capable of providing data at a scale that will support management and scientific needs [2]. Furthermore, E-monitoring has the potential to expand the data collected by freeing at-sea observers to concentrate on data fields or tasks that cannot be collected via E-Monitoring.

    Review and Planning

    This category includes review and planning meetings or workshops considering species groups or individual species and where a broad range of information is considered. For example, fisheries, biological and ecological data (gaps and quality), mitigation techniques, role of observers, regulations, population level assessment and research prioritisation. Research plans (and progress on meeting their objectives) are also included in this category.

    Shark Finning Restrictions

    Some tuna RFMOs have adopted regulations that aim to halt the practice of shark finning, in which sharks are landed onboard and their high value fins removed. Shark finning restrictions include regulatory requirements such as the use of fin-to-carcass-weight ratios, 'full retention', i.e.,  prohibition of removal of shark fins at sea, or similarly, that all sharks be landed with their fins naturally attached (fully or partially). Regulations may prohibit fishing vessels from retaining on board, transshipping, landing, or trading any fins harvested in contravention of a regulation.

    Tagging Studies

    Bycatch management is becoming increasingly dynamic. Tagging studies, using technologies such as satellite telemetry, collect information on both bycatch and target species to identify and characterize their habitat**. These habitat data can be used with fisheries data, such as effort and bycatch interaction rates, to identify habitat or interaction 'hotspots' and inform management.