I came across a piece on Fish & Aquatic News this past Sunday in which authorities in Spain confiscated 11 tons of shark fins. It simply reminded me that the Mediterranean Sea is a poster child for overfishing and already at the mercy of an irresponsible tuna industry. Yet, what I did not fully realize was that there has been an incredible decline in sharks over the last 200 years in this region alone.
In a 2008 publication in Conservation Biology, it was found that:
“Only 5 of the 20 large predatory sharks were detected at levels of abundance sufficient for analysis. Moreover, these 5 species showed rates of decline from >96 to >99.99%, which may classify them as critically endangered according to IUCN criteria.”
Even more disturbing is that the authors contend the depleted numbers may mean the large sharks are “functionally extinct” in the Northwestern Mediterranean. So, continued harvesting of sharks only for their fins is adding insult to injury on these cartilaginous ocean inhabitants.
After a rudimentary investigation on Spain’s fishing practices, I found that most of their longlines are actually set on the Atlantic ocean side, which may be compounding the dwindling Mediterranean shark populations. Because overharvesting (i.e. 11 tons of shark fins) is taking place, we are effectively limiting the ability for Atlantic and Mediterranean sharks to replenish falling populations and/or exchange individuals via the “critical migration corridor” in the Strait of Gibraltar.
With up to 2000+ pelagic longlining boats traversing the Mediterranean Sea, a considerable illegal fisheries industry continuing operations, and lackluster regulatory action, top predators responsible for structuring ocean communities will continue to be at under threat of extinction.
photo credit: Erik Charlton
Loss of Large Predatory Sharks from the Mediterranean Sea, Conservation Biology
Volume 22, Issue 4, Date: August 2008, Pages: 952-964