Are Sea Otters Dying Because of Cats?

Who would think that cats might be responsible for hurting or even killing sea otters? It's true, but cats are really only indirectly responsible for the fate of sea otters. There is a parasite called Toxoplasma gondii or T. gondii that can infect housecats and sea otters and cause a disease known as Toxoplasmosis. Toxoplasmosis can cause brain damage and seizures in otters, preventing them from feeding. So, how does the T. gondii parasite get into the sea otters? The story might surprise you.

T. gondii lives in the intestines of some cats. The parasites then produce spores called oocytes that are shed in the feces of the cat. If this fecal matter ends up in the ocean, sea otters can become infected. But how can this happen? It's actually very easy.

First of all, we need to have a quick discussion about the differences between the sewer and storm water systems. This is important, trust me. The sewer system is the water system that drains water from the toilet, shower, dishwasher, washing machine, etc. The dirty water then goes through a series of pipes to a wastewater treatment plant where the water is cleaned, disinfected and then discharged into nearby water supplies like creeks, streams or even directly into the ocean. The storm water system is the system that drains water from outside, such as rainwater, water from sprinklers, etc. This water gets no treatment what so ever. Instead, it ends up draining into the closest creek, river or other water supply, carrying with it any pollution that was in the gutters, on the street or on lawns.

Now, both of these water systems play a part in transporting the T. gondii spores to the ocean. So, what does this have to do with cats? Well, outdoor cats who defecate in gardens or on lawns and don't have owners who pick up the feces, will inadvertently pollute the water supplies via the storm water system. As soon as it rains, or someone over waters their lawn, the water will wash the feces down the drain.

That explains how cats pooping outside can contaminate the ocean, but what about indoor cats? There's also a way for cat litter to create problems. There's a fairly new type of cat little that is flushable. It sure sounds like a great idea, but if a cat is infected with T. gondii, then the spores will be flushed down the toilet. Even though the water goes into the wastewater treatment facility, the plant doesn't have the capability to kill the spores because they have a hard shell. So when the 'treated' water or effluent is discharged from the plant into the water supply, the spores go with it.

Scientists aren't sure how the otters are getting the T. gondii into their bodies, but they think it could be from eating contaminated shell fish. Since sea otters are an important part of the ocean ecosystem, it's important that pet owners do their part in assuring that parasite spores don't end up in the water supply. There are a couple easy ways to do this. One is to pick up cat waste from outside and dispose of it in the trash. For litter boxes, never flush any litter or cat feces down the toilet. Instead, bag it up and place it in the trash. Once in the landfill, it'll be covered by soil and will most likely not end up in the ocean. Unfortunately, wild or feral cats can't be controlled and will defecate wherever they can. But if responsible pet owners dispose of cat waste properly, it'll help and sea otters will thrive.