Marine ecologists revealed that the adverse effects of climate change such as warmer waters could impair the growth and hunting abilities of sharks. At the end of the century, these marine animals could become smaller and poorer hunters, they said.
Researchers from the University of Adelaide's Environment Institute said that the elevated levels of carbon dioxide that result to ocean acidification have detrimental consequences for these marine animals. It will affect sharks' hunger and their ability to meet energy demands, they said. The effect will most likely cascade through entire ecosystems.
In a study issued in the journal Scientific Report, scientists studied Port Jackson sharks in several experiments. The team examined large tanks with natural habitat and prey, and found that development of embryos for these sharks was faster under increased temperatures.
However, warmer water and high levels of CO2 also increased the sharks' energy requirement. Their metabolic efficiency was reduced and their ability to locate food through their olfactory organs was affected. These led to reductions in the growth rate of Port Jackson sharks.
"In warmer water, sharks are hungrier but with increased CO2 they won't be able to find their food," said Ivan Nagelkerken, an Associate Professor and the author of the study. He said sharks grew smaller because they couldn't find food to meet their increased energy requirements.
Nagelkerken explained that with an impaired hunting ability, sharks will not be able to exert the same control over marine food webs. He also noted that having dominance over these food webs is essential for sustaining healthy ecosystems.
Meanwhile, Nagelkerkern said that sharks will still maintain their control as other marine species will also most likely be affected by warmer waters.
"The effect of ocean acidification on loss of hearing, vision and smell has been quite ubiquitous across a range of different animals, not only fish, it's also been shown in crabs, snails and other species," said Nagelkerkern.
In addition, the study found that the impact of climate change could also lead to fewer shark attacks because of the reduction in hunting. Humans aren't natural preys of sharks, but if these marine animals lose their olfactory sense, there may be less incidents of attacks,
Nagelkerkern also added that further research should be done to study how sharks' olfaction affect shark attacks.
Photo : Elias Levy | Flickr
