Climate change could have a significant impact on the survival of some shark species, according to a recent study. Researchers from the Biology of Aquatic Organisms and Ecosystems (BOREA) Lab in France found that small-spotted catshark eggs are at risk of decreased survival rates by the year 2100 under the worst-case climate scenario. However, the study also suggests that these sharks may continue to thrive under less severe climate conditions.
The small-spotted catshark, also known as the sandy or lesser spotted dogfish, currently has healthy population numbers in the northeast Atlantic Ocean near Europe. Despite this, researchers have observed signs that the species is becoming more vulnerable as the Earth warms. Lead researcher Noémie Coulon, a PhD student at BOREA, noted that habitat loss during peak egg-laying months in the summer is already affecting these sharks.
To understand how small-spotted catsharks might be impacted in the future, Coulon and her team conducted experiments with shark eggs under varying water temperature and pH conditions. They monitored the development of the embryos over several months to assess their survival rates. The results showed that under the most extreme climate scenario, only 11% of the shark eggs hatched, compared to 81% and 83% under control and moderate climate conditions, respectively.
The embryos in the worst-case scenario exhibited slower growth rates, consumed less yolk, and had difficulty forming internal gills. However, once the sharks hatched, there was no significant difference in survival rates among the groups. This could be attributed to decreasing water temperatures as the year progressed.
While these findings are concerning, experts believe that the most extreme climate scenario is unlikely to occur. This provides some hope that small-spotted catsharks and similar species may still have a chance at survival if greenhouse gas emissions are reduced. Coulon emphasized the importance of these findings in highlighting the sensitivity of marine species to environmental changes and the need to take action to mitigate climate impacts.
In conclusion, the study sheds light on the potential consequences of climate change on shark populations and underscores the importance of addressing environmental issues to protect marine species. By understanding how sharks respond to changing ocean conditions, researchers can work towards conservation efforts to ensure the long-term survival of these iconic animals.
