Nepal | August 09, 2020

Fish more vulnerable to warming water than first thought

ASSOCIATED PRESS
Share Now:

Global warming looks like it will be a bigger problem for the world’s fish species than scientists first thought: A new study shows that when fish are spawning or are embryos they are more vulnerable to hotter water.

With medium-level human-caused climate change expected by the end of the century, the world’s oceans, rivers and lakes will be too hot for about 40% of the world’s fish species in the spawning or embryonic life stages, according to a study in Thursday’s journal Science. That means they could go extinct or be forced to change how and where they live and reproduce.

This 2014 microscope photo provided by Dr. F. Dahlke shows 1.5 mm diameter eggs of Atlantic cod (Gadus morhua). Global warming looks like it will be a far bigger problem for the world’s fish species than scientists first thought, since a study led by Dahlke released on Thursday, July 2, 2020 shows that when fish are spawning or are embryos they are far more vulnerable to hotter water. Photo: Dr. F. Dahlke via AP

Until now, biologists had just studied adult fish. For adult fish, around 2% to 3% of the species would be in the too-hot zone in the year 2100 with similar projected warming. So using this new approach reveals a previously unknown problem for the future of fish, scientists said.

In a worst-case climate change scenario, which some scientists said is increasingly unlikely, the figure for species in trouble jumps to 60%.

These vulnerable times in the life of a fish make this a “bottleneck” in the future health of species, said study co-author Hans-Otto Portner, a marine biologist at the Alfred Wegener Institute in Germany.

A marine heatwave last year, known as a blob, caused large numbers of migrating salmon to die throughout Alaska’s rivers. It also killed off cod eggs, showing what a warmer future might be like, said study lead author Flemming Dahlke, a marine biologist at the institute.

“With spawning fish and embryos most sensitive to warming waters, it means fish populations won’t be able to replace themselves,” said Rutgers University ecologist Malin Pinsky, who wasn’t part of the study but praised it. “Without reproduction and offspring, we have no fish, no fishing and no fish on our plates.”

In studying 694 species, Dahlke and Portner found some of the fish likely to be hardest hit by this phenomenon include Alaska pollock —  the biggest fishery in the United States and the source of fast food fillets — and well-known species such as sockeye salmon, brown trout, bonito, barracuda and swordfish.

“The more we allow temperature to change … the more we will lose the natural foundation of human life, including food from the sea,” Portner said.

When it gets too warm for spawning, the species could still possibly move to someplace cooler or spawn at another time, but that’s not easy, Dahlke said. “This could mean a lot of problems to many species.”


Follow The Himalayan Times on Twitter and Facebook

Recommended Stories:

More from The Himalayan Times:

Coronavirus , vaccines, vaccines trails

Are we thinking about COVID-19 vaccines yet?

It is now clear that for Nepal, like every other country, vaccines are going to have a crucial role in getting rid of the COVID-19 pandemic. What are we doing to source a vaccine when it becomes available?  Many countries understand that every month’s delay in deploying vaccines for COVID-19 w Read More...

Air India repatriation flight crash-lands, at least 17 killed

KOZHIKODE: At least 17 people were killed and more than 100 injured when an Air India Express passenger plane repatriating Indians stranded by the COVID-19 pandemic overshot the runway in heavy rain near the southern city of Kozhikode on Friday, officials said. The Boeing-737 flight from Dubai to Read More...

Government casts doubt on August 17 resumption of flights, rules out complete lockdown

Khatiwada casts doubt on August 17 resumption of flights Requests the public not to panic KATHMANDU, AUGUST 7 The government has ruled out another complete lockdown, the kind that was imposed on March 24. Unveiling recent decisions taken by the Cabinet, Spokesperson for the governme Read More...

War of words hots up in ruling Nepal Communist Party

KATHMANDU, AUGUST 7 Factions led by Prime Minister KP Sharma Oli and Co-chair of the ruling Nepal Communist Party (NCP) Pushpa Kamal Dahal and senior leader Madhav Kumar Nepal have escalated their war of words, with Oli's Political Adviser Bishnu Rimal warning party Spokesperson Narayan Kaji Shre Read More...

Government urged to guarantee citizenship rights of minorities

KATHMANDU, AUGUST 7 Nepal’s denial of human rights protection and government service to non-citizens makes the establishment of citizenship particularly important, especially for marginalised and disadvantaged people, reads a report released by the International Commission of Jurists yesterday. Read More...

Teachers vandalise campus chief’s office

POKHARA, AUGUST 7 Part-time teachers of Prithvi Narayan Campus of Pokhara vandalised the campus chief’s office today, accusing him and the concerned university of being apathetic towards their demands for a long time. The teachers and their organisation, Part-time Teachers’ Association, ha Read More...

World Breastfeeding Week-2020 amidst COVID

KATHMANDU, AUGUST 7 As the world marks Breastfeeding Week amidst the COVID-19 pandemic spread, World Health Organisation and partners are focusing on increasing mothers’ access to skilled breastfeeding support, calling on governments to protect and promote skilled counselling, a critical compon Read More...

Sagarmatha Zonal hospital in Rajbiraj. Photo: THT

Gajendra Narayan Singh Hospital shuts down services

RAJBIRAJ, AUGUST 7 Services have been closed at Gajendra Narayan Singh Hospital of Rajbiraj after as many as 34 health workers of the hospital have been confined to isolation and quarantine facilities. According to the hospital’s Acting Medical Superintendent Dr Ranjit Kumar Jha, surgical an Read More...