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Epilogue

  • José Luis CortEmail author
  • Pablo Abaunza
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Part of the SpringerBriefs in Biology book series (BRIEFSBIOL)

Abstract

The traps that catch bluefin tuna in the Strait of Gibraltar have provided work, wealth and food for thousands of years, and are additionally a bottomless source of information for historians, scientists and the public in general. Fishing for this species both in the Atlantic and the Mediterranean has always been sustainable, no written testimony ever having certified that human intervention had affected the overexploitation of the species. But that all changed at the end of the 1940s following the Second World War when new fisheries began to develop in the Atlantic. The main ones were those of northern Europe, mainly in Norway, with the introduction of purse seine, in which spawners were caught, and in the Bay of Biscay mainly targeting juveniles. In 1958 purse seine fishing for juveniles began in Morocco (the Atlantic part).

9.1 Epilogue

The traps that catch bluefin tuna in the Strait of Gibraltar have provided work, wealth and food for thousands of years, and are additionally a bottomless source of information for historians, scientists and the public in general. Fishing for this species both in the Atlantic and the Mediterranean has always been sustainable, no written testimony ever having certified that human intervention had affected the overexploitation of the species. But that all changed at the end of the 1940s following the Second World War when new fisheries began to develop in the Atlantic. The main ones were those of northern Europe, mainly in Norway, with the introduction of purse seine, in which spawners were caught, and in the Bay of Biscay mainly targeting juveniles. In 1958 purse seine fishing for juveniles began in Morocco (the Atlantic part).

When in 1963 the catches of the traps in the Strait of Gibraltar suddenly fell and a few years later the fisheries of northern Europe collapsed, nobody knew what was happening nor why. This crisis in catches brought with it the closure of most of the traps and the dissolution of the Tuna Trap Fishing National Consortium, creating misery in a sector that had survived for millennia.

In the article by Cort and Abaunza (2015) the fundamental factor behind those events is shown to be related to the massive juvenile exploitation that began in the Bay of Biscay in 1949. Thus, the analysis made on the Atlantic ABFT juvenile population reveals a clear interaction between the juvenile fisheries of the Bay of Biscay and Morocco (Atlantic part) and those of spawners in the Strait of Gibraltar and northern Europe. The overfishing of juveniles that took place in these fisheries from the 1950s until the 2000s left a gap in the generations of spawners for decades. The first outstanding effect took place in 1963, the year in which the set of ABFT cohorts that had made up the catches of the traps and northern European fisheries had already passed, in at least one year and in most cases four, through the juvenile fisheries of the eastern Atlantic in which 6.9 million ABFT juveniles had been caught between 1949 and 1962 (491,426 fish/year). Juvenile catches on a similar scale were the main cause of the lower recruitment from juvenile ages to adults, which left future generations of spawners very much reduced. This led to the immediate decline of the spawner fisheries which brought with it the collapse of the northern European fisheries at the beginning of the 1980s. The traps, however, were able to survive albeit at CPUE levels three times lower than those obtained between 1914 and 1950 (Cort et al. 2012).

The analyses made for the periods 1970–2006 and the present (2009) shows that the catches prior to the implementation of the PARP in 2008 (285,859 fish/year) were not sustainable, which meant very high fishing mortality rates (F) that prevented the recruitment of fishes to the spawner fisheries. With the reduction of the juvenile catch, which is now ongoing, it has all returned to how it was historically. The abundance of spawners in our times is a global phenomenon in the fisheries of the eastern stock (ICCAT 2017).

With the publication of these results the authors have contributed to the clarification of facts that occurred over 55 years ago and which led to the fall of two of the oldest fisheries of our seas. This information was supplied in 2016 to the ABFT assessment group of the SCRS, which should have paid it the attention that a find of this nature deserved and taken note in order to, at the very least, avoid a repetition of any similar cases in the future. Nevertheless, the group failed to make any reference to these facts in its latest analysis and report in 2017 and so their origins and terrible consequences have been buried.

We wish to conclude with the phrase of G. Santayana (1863–1952), who said: “Those who cannot remember the past are condemned to repeat it” (Santayana 1905).

References

  1. Cort JL, Abaunza P (2015) The fall of tuna traps and collapse of the Atlantic Bluefin Tuna, Thunnus thynnus (L.), fisheries of Northern Europe in the 1960s. Rev Fish Sci Aquac 23(4):346–373. http://dx.doi.org/10.1080/23308249.2015.1079166
  2. Cort JL, de la Serna JM, Velasco M (2012) El peso medio del atún rojo (Thunnus thynnus) capturado por las almadrabas del sur de España entre 1914–2010. Col Vol Sci Pap ICCAT 67:231–241Google Scholar
  3. ICCAT (2017) Report of the 2017 ICCAT bluefin stock assessment meeting. Madrid, Spain, 22–27 July 2017, 106 pp. http://iccat.int/Documents/Meetings/Docs/2017_BFT_ASS_REP_ENG.pdf
  4. Santayana G (1905) The life of reason. Reeditado en 2005 por Editorial Tecnos. ISBN 9788430942510, 320 ppGoogle Scholar

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Authors and Affiliations

  1. 1.Centro Oceanográfico de SantanderSpanish Institute of OceanographySantanderSpain
  2. 2.Spanish Institute of OceanographyMadridSpain

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