Preliminary study of the relative fishery impacts on non-tuna species caught in various tuna fisheries

All fishing methods have some type of unintentional environmental impact. One impact that receives a lot of attention is the incidental catch of non-target species, often referred to as "bycatch". The purpose of this study is to provide descriptions of stock status (if available) and the relative impacts of different fisheries based on their current/recent levels of effort (if known), on non-tuna species caught incidentally in tuna fisheries (with an emphasis on those species that are caught by purse seine fisheries).
The information used was obtained primarily from the available tuna Regional Fishery Management Organization's (tRFMO) scientific papers and scientific committee reports. In most cases, the available catch data for bycatch species is very sparse. Only in a few cases stock assessments have been conducted or attempted, resulting in a thorough compilation of catch data for different gears, and even in those cases, important data gaps may still exist. This study thus helps to identify data gaps and research required to better characterize tuna fishery impacts on non-tuna species.
As the information available on these species is very sparse, this study should be viewed as an initial attempt to compile all available information so as to better understand overall fishery impacts on non‐tuna species. The authors would be grateful to readers of this report who identify any errors or omissions so that they can be addressed in a subsequent update.