Thousands of Dolphins and Sea Lions Washing Up Dead on California Coast

Thousands of dolphins and sea lions have been washing up dead on the coast of California throughout the month.

There have been over a thousand reports of sick and dead mammals washing ashore, between June 8 and June 14, according to the National Oceanic and Atmospheric Administration.

The cause for the deaths of these sea creatures has been identified as harmful algae growing in large numbers along the Southern California coast.

"We are managing more than 200 reports of marine mammals in distress each day. We are doing the best we can to keep up with the intense pace. Please continue to report all sick and injured marine mammals as we are getting to as many animals as we can, as quickly as we can, each day," Ruth Dover, co-founder and managing director of the Channel Islands Marine & Wildlife Institute, which fielded the reports, said in a statement.

The algae bloom, known as Pseudo-nitzschia, produces an abundance of a neurotoxin called domoic acid. When marine mammals ingest the acid—through infected prey—it can cause severe health effects.

The algae can be found in a variety of watery habitats, from coastal to open ocean. This is because it can thrive in a diverse range of temperatures.

Blooms occur when there are increased nutrients in the ocean, or when the seawater is at a higher temperature than normal. It can also thrive when there is a lot of light.

While it is normal for the California coast to witness seasonal algal blooms, their spread depends on ocean conditions.

There is evidence to suggest that the algal bloom has spread further this year due to the number of dolphins being washed ashore. This is because nearshore sites are not indicating algal blooms.

Scientists have said that the increased numbers of algal blooms across the world are due to climate change.

As global water temperatures increase, so do these blooms, which can prove a hazard to marine life.

Humans are not affected by this particular algal bloom unless they consume it. For example, shellfish may be infected with the toxins, which if eaten, can cause Amnesic Shellfish Poisoning in humans.

"We are trying to learn as much as we can as fast as we can. As difficult as it is to see these animals die, we want to gather information to help understand how and why this is happening the way it is," Michelle Berman Kowalewski, founder and director of the Channel Islands Cetacean Research Unit said.

In March this year, algal blooms known as red tides—of the dinoflagellate algae species Karenia brevis—were found responsible for killing thousands of fish along Florida's coast. The bloom, which appears red at the surface, decimated seagrasses and wiped out large numbers of other marine animals like manatees.

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