A multidisciplinary approach to establishing a shifting baseline for the Japanese dogfish (Squalus suckleyi)

Since Daniel Pauly coined the term "shifting baseline syndrome" in 1995, it has increasingly gained traction in the marine conservation community and is finally starting to be accepted by some policy makers as a more accurate... [ view full abstract ]

Since Daniel Pauly coined the term "shifting baseline syndrome" in 1995, it has increasingly gained traction in the marine conservation community and is finally starting to be accepted by some policy makers as a more accurate benchmark to base total allowable catch on. The main obstacle for the establishment of a shifting baseline is data paucity. Detailed catch data has been recorded for a few decades at best in most cases. Therefore, establishing a shifting baseline relies on a multidisciplinary approach based on social sciences and marine environmental history, which is still often met with skepticism in the marine sciences, even though accepted in terrestrial science for years.

This paper presents a case study of an integrated approach to establish if a shifting of the baseline of the North Pacific dogfish (Squalus suckleyi) occurred and details the methods used: landing data, portside visits, interviews with fishermen and shark processors of three generations, museum visits, and study of old documents and photographs. The result shows that a massive shift occurred at the turns of the 19th to the 20th century that lead to what can probably be described as the ecological extinction of S. suckleyi on the Pacific Sanriku coast of Northern Japan. S. suckleyi remains unmanaged and unprotected, while other shark species, which are now the focus of commercial fisheries in Japan, are increasingly regulated based on visible trends in landing data which currently constitutes the only acceptable foundation for policy decisions.