Warmer seas kill shark eggs

Warmer sea water in combination with acidification can pose a great danger to the sea's sharks. Their eggs develop much worse, which leads to the embryo dying, according to a new study.

» Updated: July 16 2024

» Published: July 05 2024

Warmer seas kill shark eggs
Photo: Björn Larsson Rosvall/TT

Warmer seawater in combination with acidification can pose a great danger to sharks in the oceans. Their eggs develop much worse, which leads to the embryo dying, according to a new study.

The study, which was recently published in connection with a scientific conference in Prague, is based on experiments with eggs from small-spotted catshark (Scyliorhinus canicula), a small species that is common along Europe's coasts, including the Swedish West Coast.

The researchers, led by biologist Noémie Coulon at the marine biological laboratory in Dinard in Brittany, France, tested how the eggs coped with temperature increases according to two of the scenarios worked on by the UN's climate panel IPCC. In one case, the test was based on a rise of two degrees Celsius by 2100, and in the other, a rise of four degrees. The latter could be the case if greenhouse gas emissions are not significantly reduced.

Increased mortality

At the same time, it was assumed that the oceans are becoming increasingly acidic as the temperature rises. Consequently, the researchers lowered the pH value in the water in both tests.

It must also be taken into account that seawater, in this case off Brittany, is significantly colder in winter than in summer. The water is warmest in August.

The result is telling. The development of the eggs was normal, and 83 percent of all embryos survived when the temperature increase was moderate. Lively little sharks hatched into the world.

But when the temperatures rose to far above normal, it went worse. Mortality increased dramatically, especially in August, and only 11 percent of all embryos survived until hatching. It was clear that their growth was slower. In most cases, the gills were not fully developed either.

Great concern

The researchers themselves say they were shocked by the mortality. The world's oceans have clearly become warmer since at least the 1980s. The increase in surface water temperature is now around 0.8 degrees above the average for the 20th century, which has raised great concern among researchers. It is well known that coral reefs are taking a hit, but there are fears that many other organisms will also be affected.

At the same time, Noémie Coulon points out that the fact that 11 percent of the shark embryos survived raises some hope. It shows that individual variation is great, which means that natural selection has a lot of material to work with. The species may therefore be able to cope when the environment changes.

The small-spotted catshark (Scyliorhinus canicula) is a small species, at most one meter long. It occurs from Norway down to the Mediterranean and Senegal. In Sweden, it is common along the West Coast. The diet consists of fish, crustaceans, and mollusks. The species has no specific breeding season but mates throughout the year. The eggs, or rather the egg capsules, are anchored with threads on suitable objects on fixed substrates. They hatch after eight to nine months. The species is protected, just like other sharks.

Source: The Swedish Agency for Marine and Water Management.

Tags

TTT
By TTThis article has been altered and translated by Sweden Herald

More news

Suspected Murder in Hässleholm: One
1 MIN READ

Suspected Murder in Hässleholm: One Person Detained

Teenage Girl Stabbed on Bus
1 MIN READ

Teenage Girl Stabbed on Bus in Eslöv; Four Teens Arrested

Ex-Regional Official in Sweden Faces
1 MIN READ

Ex-Regional Official in Sweden Faces Charges in Pension Fund Bribery Case

Shingles Vaccine Linked to Lower
2 MIN READ

Shingles Vaccine Linked to Lower Dementia Risk in Older Adults

Critics Challenge Proposal to End
3 MIN READ

Critics Challenge Proposal to End Summer Grazing for Swedish Dairy Cows

Sweden Proposes Transparency for Lottery
1 MIN READ

Sweden Proposes Transparency for Lottery Purchases Supporting Parties

Elderly Man's Death in Gullspång
1 MIN READ

Elderly Man's Death in Gullspång Fire Investigated as Suspected Murder

Sweden Tightens Control on Opioids
1 MIN READ

Sweden Tightens Control on Opioids and Hazardous Substances

Sweden Braces for Economic Impact
2 MIN READ

Sweden Braces for Economic Impact from US Tariffs, Government Warns

Swedish Man Faces Arson Charges
1 MIN READ

Swedish Man Faces Arson Charges for House Fire in Norway

Man Charged in Fatal Lund
1 MIN READ

Man Charged in Fatal Lund Knife Attack Linked to Drug Deal

Electric Scooter Accidents Surge by
1 MIN READ

Electric Scooter Accidents Surge by 30 Percent in 2024, Young Riders Most Affected

Skåne Manager Faces Charges for
1 MIN READ

Skåne Manager Faces Charges for Embezzling Millions from Municipalities

Teen Faces Court in Sweden
2 MIN READ

Teen Faces Court in Sweden for Alleged Sect-Linked Knife Attack

Elderly Man Critically Injured in
1 MIN READ

Elderly Man Critically Injured in Kävlinge Villa Fire

Somalia Expels Swedish Aid Chief
1 MIN READ

Somalia Expels Swedish Aid Chief Anna Saleem Högberg

Sweden Proposes Tighter Security at
2 MIN READ

Sweden Proposes Tighter Security at Migration Detention Centers

Swedish Foreign Minister to Discuss
2 MIN READ

Swedish Foreign Minister to Discuss Journalist's Detention with Turkey

Casino Cosmopol in Stockholm to
1 MIN READ

Casino Cosmopol in Stockholm to Close Following Riksdag Decision

Sweden's Malmer Stenergard to Discuss
2 MIN READ

Sweden's Malmer Stenergard to Discuss Journalist's Detention with Turkey

Parents in Sweden Jailed for
1 MIN READ

Parents in Sweden Jailed for Locking Children in Basement

75-Year-Old Woman Cleared of Murder
1 MIN READ

75-Year-Old Woman Cleared of Murder Charges in Ale

Bribery Convictions in Sweden See
1 MIN READ

Bribery Convictions in Sweden See Rise in Gross Offenses

Suspect Detained in Norrköping Murder
1 MIN READ

Suspect Detained in Norrköping Murder Investigation

Sabotage Cuts Power to 500
1 MIN READ

Sabotage Cuts Power to 500 Homes in Småland, Police Investigate

Twelve Indicted in Major Scania
1 MIN READ

Twelve Indicted in Major Scania Drug Network Bust

Sun-Seeking App Trend Raises Skin
2 MIN READ

Sun-Seeking App Trend Raises Skin Cancer Concerns in Sweden

Sweden Braces for Year's Warmest
1 MIN READ

Sweden Braces for Year's Warmest Day Before Cold Snap Hits

Online Sect's Influence on Teen
4 MIN READ

Online Sect's Influence on Teen Knife Attacks Faces Court Scrutiny

Swedish Man Sentenced to 10
1 MIN READ

Swedish Man Sentenced to 10 Years for Long-Term Abuse of Relative

Man Critically Injured in Sollefteå
1 MIN READ

Man Critically Injured in Sollefteå Workplace Accident

Child Seriously Injured After Fall
1 MIN READ

Child Seriously Injured After Fall from Window in Stockholm

Sweden's Spring Covid Vaccine Campaign
2 MIN READ

Sweden's Spring Covid Vaccine Campaign Focuses on High-Risk Groups

Stockholm Police Launch Pilot to
2 MIN READ

Stockholm Police Launch Pilot to Curb Violence Against Women

Anna-Karin Hatt Declines Centre Party
1 MIN READ

Anna-Karin Hatt Declines Centre Party Leadership Role

Expert Group to Guide Västra
1 MIN READ

Expert Group to Guide Västra Götaland After Millennium System Setback

Kristersson Calls for Doubling Sweden's
3 MIN READ

Kristersson Calls for Doubling Sweden's Conscription Numbers

Woman in Her 60s Killed
1 MIN READ

Woman in Her 60s Killed in Collision with Truck Near Kristianstad

Three Men Charged in Assault
1 MIN READ

Three Men Charged in Assault and Rape Case in Kristianstad

Sweden Proposes Stricter Housing Rules
3 MIN READ

Sweden Proposes Stricter Housing Rules for New Immigrants