Fish's sense of sight, smell and hearing becomes impaired due to rising carbon dioxide levels
The survival instincts of fish have been impaired by climate change,
causing them to swim towards danger instead of away from it. This is
the conclusion reached by a team of marine biologists at the University
Their findings have been published in the latest issue of
Global Change Biology journal.
Based on their research, the fish's sense of sight, smell and hearing
becomes impaired in the presence of rising carbon dioxide levels. Their
subsequent abnormal behaviour is linked to how carbon dioxide disrupts
the way the brain processes the signals from the body’s sensory organs.
In light of projections in which carbon dioxide levels are expected to
increase 2.5 times by the end of this century, the research team –
comprising Dr Robert Ellis and Dr Rod Wilson from the university, and
Dr Urbina from Chile – have turned their sights to fish farms. Here,
they believe, lies the key to establishing the long-term impact of
carbon dioxide on marine life. This is because farmed fish often live
in environments where the carbon dioxide levels are ten times higher
than those in the wild.
Describing the fish farms as a “giant long-term laboratory experiment,”
Dr Ellis said that aquaculture might help in climate-change
experiments. He elaborated that “there is the enticing possibility that
fish and shellfish previously grown in high CO2 aquaculture conditions
over multiple generations can offer valuable insights regarding the
potential for aquatic animals in the wild to adapt to the predicted
further increases in CO2.”
By studying farmed fish, the researchers hope to discover how aquatic
species would evolve to deal with climate change in the future.
Along the way, the aquaculture industry may also reap some benefits.
date, the research has revealed that relatively small increases in
carbon dioxide may act as a growth stimulant in some fish while
extremely high levels can reduce digestion efficiency in cod.
Dr Wilson added that “our research will allow fish farmers to optimise
conditions, and specifically CO2 levels, to improve growth and health
of their fish, profitability and the long-term sustainability of the
industry. This is really important given that aquaculture is the only
way we will increase seafood production to feed the growing human
population, particularly given wild fish stocks are overexploited.”