A new study published in the journal Science says climate change and growing sea water temperature can make aquatic habitats unliveable for 60 per cent of fish species by 2100, if temperatures keep rising at unprecedented rates.
Both saltwater and freshwater fish are the most sensitive to rising temperatures as spawning adults, and as embryos. At these life stages, fish use more energy and oxygen to survive, which unfortunately is already depleting fast in rapidly heating water bodies.
Scientists studied almost 700 species of fish — all either economically or ecologically essential to sustaining an aquatic ecosystem that feeds billions of people around the world — and found them to be most vulnerable when in reproductive or embryonic stages of their life cycle.
Organisms have to breathe in order for their bodies to produce energy; this is equally true for human beings and for fish. In addition, we know that the energy needs of humans and animals alike depend on the temperature: When it’s warmer, the need for energy rises exponentially, and with it, the need for oxygen.
On this basis, it follows that organisms can only adapt to rising temperatures in their immediate vicinity by providing their bodies with more oxygen. But there are certain species-specific limits on this ability; if those limits are exceeded, it can lead to cardiovascular collapse.
Since pre-industrial times, the planet’s temperature has slowly risen by just over 1 degree Celsius. In order to stop this rise, governments all over the world have been committing to halting this global rise at 1.5 degrees Celsius, in order to stay the devastation caused by global warming. If successful, this could limit the damage to aquatic life, to affect only 10 per cent of fish species, researchers found.
But a recent United Nations report shows this 1.5-degree Celsius limit is unlikely to hold; the world is on track to record a 3-degree Celsius spike by 2030. If we keep moving at this rate, scientists fear a worst-case scenario playing out for marine wildlife, which can increase the rate of their endangerment six-fold.