Many things can stand in the way of love. For sea stars, human pollution appears to be one of them.

Urban runoff and sewage discharges are preventing populations of the sea star species known as the bat star, Patria miniata, from breeding in the Southern California Bight, off the coast of Los Angeles.

BLOG: Starfish Suck Carbon From the Sea

A study led by biologist Jon Puritz of the University of Hawaii found discharges from water treatment systems and contaminated rivers led to genetically different sea star populations of the species.

The authors of the study ruled out other possible reasons for the genetic variations. The bat star is not harvested by people, so the fishing is not impacting the population. Earlier studies had also found that the species normally inter-breed from Southern California to Canada.

“This study changes the scale at which we thought human beings can affect non-harvested marine species. These results have the potential to change the way anthropogenic factors are incorporated into marine reserve design and ecosystem-based management, ” said Puritz in a University of Hawaii press release.

The research was recently published in the journal Nature Communications.

The impact of human population on the coast has not been studied much. Understanding the effects of Los Angeles on the animals living in nearby areas of the Pacific Ocean helps scientists understand what the waste from millions of people flowing into the ocean does to the creatures living there.

BLOG: Taking Showers Could Contaminate Drinking Water

“This species was previously shown to have well-connected populations from Southern California to Southern Canada, but now we see that these urban runoff plumes in the Los Angeles area are a more significant hurdle for the microscopic larvae to cross than the remainder of the Pacific coast of the U.S.,” said co-author Rob Toonen in the University of Hawaii press release.

IMAGE 1: The bat star, Patria miniata. (COURTESY: Jon Puritz)

IMAGE 2: The bat star, Patria miniata. (COURTESY: Jon Puritz)