Sick sea lions washing ashore in California due to algae bloom

Source: The post is based on the article “Sick sea lions washing ashore in California due to algae bloom” published in The Hindu on 29th June 2023

What is the News?

Hundreds of sea lions are found dead or sick on California beaches due to toxic offshore algae blooms.

What are Sea Lions?

Sea Lion is a marine mammal in the scientific group pinniped, meaning “wing foot” or “feather foot”. They belong to the family Otariidae.

They are known for their semi-aquatic lifestyle, spending a significant amount of time both on land and in the water.

They are carnivores, eating fish, squid, crabs, and clams. The largest species, the northern sea lion also eats seals.

Currently, there are six subspecies of sea lions: Australian sea lions, California sea lions, Galápagos sea lions, New Zealand sea lions, South American sea lions, and Steller sea lions.

What is Algal Bloom?

An algal bloom or algae bloom is a rapid increase or accumulation in the population of algae in freshwater or marine water systems. It is often recognized by the discoloration in the water from the algae’s pigments

Algal Bloom is a natural phenomenon, but can also occur because of human causes such as climate change and an excess of nitrates washed out to sea.

Algal blooms cause the production of a neurotoxin called domoic acid.

While some marine life is not affected at all by domoic acid, the neurotoxin can accumulate in animals lower on the food chain and affect those higher up who are feeding on the filter fish that count algae as their main food source. 

Sea lions, who eat huge amounts of filter fish or other organisms, seem to be especially susceptible to domoic acid as a neurotoxin.

Note: Humans are unaffected unless they eat infected shellfish.