Review of the life history, fisheries, and stock assessment for small tunas in the Atlantic Ocean

Despite being an important source of wealth and food security for many countries, most of the small tuna stocks in the Atlantic Ocean and Mediterranean Sea remain unassessed. In this study, we summarized the current state of knowledge of this group of species reviewing the information available on life history parameters, stock structure, historical catches, size frequency distributions and current knowledge of stock status. In relation to the life history parameters, data are overall scarce and mainly missing in the Eastern Atlantic where small tunas are relevant in small-scale fisheries. From the 27 defined stocks, only 11 have been quantitatively assessed. From those, the Northwest wahoo and the Southeast little tunny stocks may be experiencing overfishing, deserving priority management attention. Length-based rather than catch-based methods showed a more promising applicability for small tunas, although representative length distributions from the catch are scarce for some stocks. Historical catch time series for small tuna are still incomplete, however, the last two decades are the most accurate and could be considered in future assessment methods. The gaps of knowledge related mainly to life history parameters and historical catches are the main reason why most of these stocks remain unassessed and unmanaged.