The impacts of climate change on fish
There are few topics discussed and debated more these days than climate change. And rightly so. People may disagree about the reasons and the extent of its impact, there have undeniably been several alarming signs and phenomena clearly linked to it.
While climate change affects the entire globe, it is no wonder that our seas and oceans are especially affected since roughly 70% of the Earth’s surface area is covered by water.
The most important effects of climate change on our oceans are shifts in temperature, deoxygenation, acidification and changes in currents. No wonder all this is happening since oceans absorb as much as 93% of the heat accumulated in the Earth’s atmosphere, as well as a quarter of the CO2 released from fossil fuels.
As a result, marine heatwaves have jumped by over 50% in the past 30 years. Ocean temperatures are estimated to rise by 1-4°C by the year 2100.
How does all this affect marine life? Swift increases in temperature and acidification can lead to the loss of marine habitats and even species, while shifting currents are changing the distribution of fish stocks.
(Photo: Clker Free Vector - Pixabay)
Interestingly, this change in distribution has a double impact. While tropical areas are forecast to see a drop of up to 40% in potential seafood catch by 2050, higher-altitude areas – such as the North Pacific – are seeing a rising number in the range of some species.
Another impact of climate change is the process called deoxygenation that oceans, coastal seas, rivers and lakes undergo. It happens because warmer waters hold less dissolved oxygen than cooler waters.
When the levels of dissolved oxygen fall to 2 milligrams per liter, as opposed to their usual range of 5-10 milligrams per liter – several organisms suffer serious stress that scientists call “hypoxia.”
Some people may wonder after all whether they can still eat fish. (While many individual anglers prefer catch-and-release, even they may eat fish, so they will probably not mind it either that we also discuss the impact on eating fish.)
It is advisable to opt for MSC-labeled fish and seafood. This way we can be certain that the fish we eat is from fisheries that are well-managed plus more prepared for environmental changes. They also keep an eye on scientific recommendation to make sure their operation is sustainable.
(Photo: Foundry Co - Pixabay)
Moreover, fishing has less impact on climate than consuming other proteins. Studies show that each kilo of fish caught produces 1 to 5 kilos of carbon, whereas red meat production – something we keep being warned about – can range from 50 to 750 kilos of carbon per meat!
Sources: https://www.msc.org
(Cover Photo: Gerd Altmann - Pixabay )