School of Natural and Environmental Sciences


BY-Catch Assessment and Mitigation in Western Indian Ocean Fisheries (BYCAM)

PhD student Andrew Temple taking body measurements of a bullshark (Carcharhinus leucas), caught in the artisanal longline fishery

Providing sustainable fisheries for the future by addressing bycatch in the Western Indian Ocean.


Specifically this project will include assessment of bycatch of large, non-target vulnerable megafauna species, provide realistic mitigation measures and recommendations for governance & management. Thereby facilitating ecological and socio-economical sustainable artisanal, small-scale commercial and semi-industrial fisheries in the WIO. Vulnerable megafauna are of particular interest as they are extremely vulnerable to non-natural mortalities as a result of late maturity and low reproductive rates, whilst being important for the stability of ecosystems.

The project will focus on three types of artisanal, small-scale commercial and semi-industrial fisheries with known bycatch problems: prawn trawls and coastal longlines and gillnets (drift and bottom-set). The work will be focussed in Kenya, Mozambique, Tanzania, and Zanzibar with a small-scale case study in Madagascar. To address the identified gaps in our understanding, a number of research objectives will be delivered and recommendations for bycatch assessment and mitigation methods for respective fishing gear will be proposed for future sustainability and management.


  1. Review of current WIO fisheries monitoring activities and their management efficacy.

  2. Collection and assessment of prawn trawl and coastal gillnet and longline fisheries effort data in Kenya, Tanzania, Zanzibar and Mozambique, using official fisheries statistics and observer networks.

  3. Collection and assessment of bycatch data, species and rates for elasmobranchs, marine mammals and sea turtles in coastal fisheries through use of observers & fisher networks.

  4. Evaluation of existing bycatch mitigation methods where these exist.

  5. Evaluation of observed (using observers & fisher networks) bycatch composition and rate against those reported through RBAs to assess reliability.

  6. Survey of socio-economic importance of species and perceptions of stakeholders towards these species including their non-consumptive value, their ecosystem importance and sustainability especially under future scenarios of megafauna removal and likely impacts on trophic foodweb dynamics.

  7. Pros and cons of different management measures considered alongside policy, governance, socio-economic behavioural drivers, markets and livelihood issues.

  8. Constraints to management mitigation measures and critical factors affecting economic and social performance indices will be identified and used to inform development of good governance support and policy reform so they are developed at the same time and not at the end as an ‘add-on’.

  9. Collection of life history parameter data (age, growth curves, reproductive capability, age of maturity) for selected megafauna species of high bycatch rate in order to perform demographic analysis and aid in stock assessment.

  10. Produce an ERA (productivity-susceptibility analysis) at the WIO scale based on RBA survey data, from semi-industrial, small-scale commercial and artisanal fisheries

  11. For marine mammal species; for those areas where data are available on population abundance and genetic population structure, assessment of bycatch impact on respective population will be conducted.

  12. Carry out a series of bycatch mitigation trials across fisheries in the region (TEDs, pingers, circle hooks and re-developed methods); assessing their efficiency and feasibility for broad scale implementation.

  13. Create an updatable spatial database with further development of a redistributable and revised atlas, fact sheets and thematic maps detailing fisheries effort, gear type, species presence (in bycatch), levels of bycatch in gear type and areas of highest risk (stress areas) for species across surveyed fishing grounds within the WIO. This will further serve to identify areas of critical importance and areas in need of more extensive work in the future.

Further information

Project website:

Contact: Andrew Temple (PhD student).


Telephone: +44 (0) 191 208 5607