Fish people love to eat will become rare due to climate change

By Gwyn Wright via SWNS

Fish that are popular to eat will become less common and harder to catch due to the warming of the oceans caused by climate change, warns a new study.

Large species and commercially important fisheries will shift out of their historical ranges as the climate warms - and will also be less abundant.

For instance, they say cod fishermen in the Atlantic might still find the species 200 years from now, but in "significantly fewer" numbers.

Fish will move to new parts of the ocean as temperatures warm, according to the study.

As oceans get warmer, interactions between the sea creatures and their predators will stop them from moving to places where they can flourish.

Researchers based in the United States and Canada found predator and prey interactions hamper the sea creatures’ ability to react quickly to rising sea temperatures.

Larger fish tend to stay in their old habitats for longer than smaller, more nimble fish because new food sources arrive in their old ranges.

Large species will move into a larger area but commercially important fisheries also trawl through more and more water to make a catch.

While well-known species such as cod may well still be found in the Atlantic in 200 years' time, it is unlikely they will be as numerous as they are today.

When there are fewer fish, overfishing in fact becomes easier because population growth rates are low, according to academics.

While previous studies of shifting habitat ranges have focused on the impact of a warming climate on individual species, they have largely failed to get to grips with how food-web interactions will affect the pace of change.

For the new study, the team looked at how trophic interactions- the process of one species being nourished at the expense of another- and other dynamics determine how climate change affects species’ ranges.

Using complex computer models, they found many species, particularly large predators, will shift their ranges more slowly than they ideally would and come under threat in warmer seas.

The computer model included parameters including metabolism, body size and optimal underwater temperature ranges.

Study lead author Dr. Edward Tekwa said: “The model suggests that over the next 200 years of warming, species are going to continually reshuffle and be in the process of shifting their ranges.

“Even after 200 years, marine species will still be lagging behind temperature shifts, and this is particularly true for those at the top of the food web.”

Study co-author Dr. Malin Pinsky said: “While the species we fish today will be there tomorrow, they will not be there in the same abundance.

“In such a context, overfishing becomes easier because the population growth rates are low.

“These dynamics will not only be in one place but globally.”

The findings were published in the journal Proceedings of the Royal Society B Biological Sciences.