Billfish and tuna, important commercial and recreational fish species, may be more vulnerable to fishing pressure because of shrinking habitat according to a new study published by scientists from NOAA, the Billfish Foundation, and the University of Miami.
An expanding zone of low oxygen, known as a hypoxic zone, in the Atlantic Ocean is encroaching on these species' preferred oxygen-abundant habitat, forcing them into shallower waters where they are more likely to be caught. According to the study, higher catch rates from these areas could give the false appearance of more abundant fish stocks.
While hypoxic zones occur naturally in many areas of the world’s tropical and equatorial oceans, scientists are concerned because these zones are expanding and occurring closer to the sea surface, and are expected to continue to grow as sea temperatures rise.
source: NOAA Fish News