Also in the Article

We analyzed the relative contribution of the world’s four primary seafood sectors: (i) capture fisheries in national waters (EEZs), (ii) capture fisheries in the high seas, (iii) capture fisheries in fresh water, and (iv) aquaculture (both marine and fresh water combined). Sea Around Us data of capture fisheries landings in EEZs and the high seas and FAO data (37) were used for freshwater landings and aquaculture production values. To get a sense of the most recent trends, we used the period of 2009–2014.

Our second analysis determined (i) the primary high seas fishing countries and (ii) key species caught on the high seas. We identified the top fishing fleets (by catch volume) and the key species caught between 2002 and 2011 using the Sea Around Us database. This time frame was chosen as these were the most recent years with trade information in FishStat (v. 3.01, obtained 11 January 2017). On the basis of these data, a total of 395 different species (for example, “bigeye tuna” and “Atlantic cod”) and taxonomic groups (for example, “unidentified marine fishes,” “deep-sea crabs,” and “unidentified pelagic fishes”) were caught on the high seas during this time. From this, we extracted the 243 species-specific entries for fish and invertebrates. Because the reconstructed Sea Around Us data used in this analysis include all forms of catch (including nontargeted species that are caught as bycatch), we assumed that not every one of the 243 species were targeted catch and that some would have been caught incidentally as bycatch in certain fisheries. To account for this, we refined this list into “targeted species” by (i) removing any species with an average annual catch of ≤1000 metric tons and (ii) removing any species with a discard/total catch of ≥10%. From these filters, 39 species remained for the subsequent analysis of trade (table S2). As the Sea Around Us data also include estimates of capture fisheries catch within EEZs, these values were used to compute the proportion of a species’ total catch that is from the high seas.

Our third analysis used the FishStat database to determine the primary importing and exporting nations of the high seas species identified in the preceding analysis. Here, we defined “primary” importers as those nations with the highest percentage (by volume) of a given species as an imported product. “Secondary” importers are those with the second highest. Unless otherwise specified, import statistics for fresh and frozen, unprocessed product forms (that is, “salted,” “dried,” “processed,” and “prepared” products were not included) for each species were obtained from this database. We also identified which high seas fishing countries had exports of the high seas species identified in the preceding analysis. Trade data were not disaggregated between EEZs and the high seas. Therefore, it was not possible to determine what proportion of a traded species or product was originally caught on the high seas. For the purpose of this study, the assumption was no difference in the importers of EEZ or high seas products of a given species, and the data presented represent imports of the total reported catch for those species. This assumption was made on the premise that the international seafood market predominantly differentiates products based on flag state (fishing country) rather than the geographic location of the catch.


Also in the Article