More on Bycatches: Changes, Evolution, and Revolution

I attempt to provide a perspective on some developments around the bycatch problem. The definition of bycatch continues to be an unsettled matter, but for most people it has a clear negative connotation, and I try to reflect that. The options to reduce bycatch are better understood using the components of bycatch estimates: effort and bycatch per unit of effort. Factors affecting BPUE can be used to find adequate strategies. The bycatch/catch ratio is useful to minimize the losses in production while reducing bycatch and it reflects the “ecological cost” of production. The evolution of the role of observers is traced through time, and the improvements developing mitigation programs are discussed. Populations: Using numbers of incidental mortalities to assess the impacts on the so-called “bycatch species” populations are simplistic and alternative metrics (e.g., the characteristics of the individuals killed) should be considered. Ecosystems: Obstacles to the progress of ecosystem-based fisheries management range from institutions and advocates with narrow foci, to the difficulties of choosing between alternative impacts. If the decisions made by managers are influenced by the intensity of the advocacy, or by the charisma of the different species, then we will be ignoring our objective of ecosystem-based fisheries management. A conceptual revolution proposes an alternative way to harvest an ecosystem based on a diversification of the harvest, reducing species, and size selectivities. This seems to be a better way to preserve the ecosystem while utilizing its resources. Even though much progress has been achieved through improvements in fishing gear technology, the real revolution has not happened: a change from gear that causes mortality to most of what is captured, and then a portion is retained, to a system based on live captures, where only those meant to be retained are killed.