Occasionally PMMC experiences a large influx of animals affected by Domoic Acid.
Domoic Acid is sometimes present in a microscopic marine plant (Pseudo-nitzschia) that is eaten by sea life and passed along up through the food chain. The toxin affects the parts of the brain and causes rapid neurological deterioration, (brain damage).
The neurological impacts make it difficult for the animals to stay afloat and breathe in the water. In many cases, marine mammals that are affected by Domoic Acid will beach (haul out of the water) in effort to rest and survive.
Affected sea lions exhibit head weaving and bobbing, bulging eyes, mucus from the mouth, disorientation and imbalanced movements. Seizures are prevalent. Pregnant mothers often abort. These animals are often unpredictable and blind and hence need to be treated with extra caution.
In most cases brain damage is permanent and severe, therefore euthanasia is the most merciful solution.
Where It comes from:
Domoic Acid is a naturally occurring marine toxin. It is the result of an extreme proliferation of marine algae, usually (but not always) of the genus Pseudonitzschia. These toxic species have been found on the East and the West Coasts of the U.S., as well as the Gulf of Mexico.
Domoic Acid is a chemical that is sometimes produced by algae or plankton after it blooms. Higher ocean temperatures trigger the seasonal algae bloom. This is an annual event occurring between March and June. The algae containing DA is eaten by sea life and passed along up through the food chain. Both shellfish and filter feeding fish (clams, mussels, anchovies, sardines, krill, etc.) can accumulate this toxin without apparent ill effects however, in marine mammals and humans, DA acts as a neurotoxin.
It is generally accepted that the incidence of problems associated with toxic algae is increasing. Possible reasons to explain this increase include currents and tides to a host of human-related causes such as nutrient enrichment (agricultural run-off), climate shifts or transport of algae species via ship ballast water.
The majority of Domoic acid victims that we get at PMMC are female sea lions. This is a result of the bloom cycle of the algae coinciding with gestation period of this species. This is the time of year when CSL are gorging themselves on fish in the last months of their pregnancy, and hence they are the animals that we see with toxic doses.
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