Temperature variations due to the climate crisis put sharks in danger

Climate change and the resulting global warming

by Lorenzo Ciotti
Temperature variations due to the climate crisis put sharks in danger
© Wikimedia Commons

Various organizations protect sharks from the main dangers that threaten them. Poaching or netting is one of the biggest dangers. Other important threats to the survival of sharks include serious alterations to their natural habitat, damage due to urban development on the coasts, pollution and the impact of fishing on the seabed species that are typically prey to these fish.

The violent practice of fin cutting, linked to the preparation of shark fin soup and mentioned in the previous paragraph, has given rise to much discussion and regulation aimed at preventing it. The acclaimed 2007 documentary Sharkwater explained how several species were driven to near extinction following the huge demand in some Asian states for fin soup. And, obviously, among all I must mention climate change and the resulting global warming.

Shark© Wikimedia Commons

The marine conservation organization Sea Shepherd, in collaboration with local authorities, has repeatedly succeeded in arresting illegal shark-hunting vessels. The owners of these ships were sometimes fined millions of euros. The lives of over a million sharks were saved because the arrested vessels were not allowed to fish while in port.

The study Shark critical life stage vulnerability to monthly temperature variations under climate change, published on the Marine environmental research, explained:

"In a 10-month experimental study, we assessed the combined impact of warming and acidification on critical life stages of the spotted catshark (Scyliorhinus canicula). Using recently developed frameworks, we distinguished individual and group responses to two scenarios projected climates for 2100. Seasonal temperature fluctuations revealed the acute vulnerability of embryos to summer temperatures, with hatching success ranging from 82% for the control and SSP2-4.5 treatments to only 11% for the SSP5 treatment -8.5 Embryo death was preceded by distinct individual growth trajectories between treatments and also revealed interindividual variations within treatments with lower energy assimilation and almost all failed to transition to internal gills by 6 months after hatching, no additional mortality was observed due to colder temperatures."