Japan, stop killing Bluefin tuna!

In Japan the Bluefin tuna is particularly prized (a single large fish can fetch more than $ 100.000). 
The large demand in this country led to aggressive fishing practices and the populations today are a tenth of what they were in the 1950s. 
The decline is faster everyday because of open-ocean pens where wild juvenile tuna are put: these animals are removed from the wild before they have spawned and this is deleterious for the survival of the species. 

http://www.worldwildlife.org/species/bluefin-tuna

JELLYFISH: a worrying invasion.

For some years now the jellyfish are causing serious damage to fishing and to industrial activities. This is happening not only in the Mediterranean Sea, but also in the Irish Sea and in the Atlantic Ocean, because of the global warming. 

In 2013 they have killed 20.000 salmons in the plants of Marine Havest, off the coast of the Irish island of Clare. Other similar episodes have occurred along the coasts of Tunisia, Spain, Normandy, Catalonia, Norway and Chile. 

This problem is not so known at the moment, but it can't be underestimated. Jellyfish cause trouble to the fish farms, but also in the open seas, where they can choke the boat motors and pile up in the nets, reducing the fish and making it hard to select it. 

Whose is the blame for all of this? 

Of course global warming is playing a fundamental role: in the Mediterranean Sea there are species that once couldn't be found there, like puffers and barracudas and the man exploiting too much the marine ecosystems reduces the competition for food, so jellyfish thrive more than the fish species. 

Furthermore, they resist well to the effects of pollution and to the acidification of the oceans. 

They threaten to wipe out marine biodiversity.