During calm mornings at the San Marcos River, students could see North American River Otters peek out over the water, indicating a healthy river ecosystem.
This year marks the otters’ sixth spring back in San Marcos since the fur trade in the 19th and 20th centuries that almost wiped out the population. The otters are now returning to return due to healthy water quality, according to Virginia Parker, executive director for the San Marcos River Foundation (SMRF).
“We’re seeing the population rebound on the San Marcos river, and that is not only indicative of a healthy ecosystem, but is also indicative of the fact that the fur trade is not as relevant today,” Parker said.
Parker said otters are native predators and help manage the fish populations, despite some people’s beliefs about them being a threat to fish.
“[Otters] love fish, crawfish and some mussels … as a predator, they’re going to kill [a] diverse [number of animals] because if there’s any species that is overwhelming, it’s going to control that,”Ivan Castro-Arellano, associate professor in biology, said.
The fact that the river otters are still present means the river is doing well and there is enough fish for them to prey on, Castro-Arellano said
According to Castro-Arellano, people can find the river otters at Sewell Park, Spring Lake or the boardwalk early in the morning when there aren’t many people around.
While the San Marcos River has been in a drought for nearly four years, Castro-Arellano said the ecosystem seems to be doing well.
“If the river gets completely dry, they cannot survive in the area; they will move to another watershed, so I assume they’d follow the river until they can jump to the next,” Castro-Arellano said. “We’re so lucky here that our Aquifer and Spring Lake is running decently. If the aquifer [dries out], we have more serious problems than the otter.”
Three of the biggest threats to the otter population are development, pollution and drought, according to Castro-Arellano.
Thomas Heard, deputy director of the ecological research and fish and wildlife biologist at the Meadows Center, said the habitat conservation plan through the Edwards Aquifer Authority, helps keep the river health. Under the plan, Heard and his team replace invasive plants with plants native to the river.
“I think observationally, we don’t have data on this, but because we have replaced much of the invasive vegetation in the river with mainly native species, it’s possible that the river has been able to remain resilient during those low flow periods,” Heard said.
Heard said that if rain contiunes missing San Marcos and the recharge zones, it’s hard to predict how bad the ecosystem could get.
Parker said when people get the chance to see the otters, it creates a special moment between the person and the river.
“… Having those emotional, special moments on the river brings people closer to the river, which is good for people’s health overall, but it creates an opportunity for them to care about the river a little bit more,” Parker said.
Parker said she saw the otters a few times and made a special connection with them on Mother’s Day.
“Within the first 10 minutes of my paddle, there was a river otter. I don’t know if they eat mussels, but that’s what I think he was eating, and I just got really quiet and sat there, and I got to watch him for about 20 minutes, and it was so special,” Parker said. “I’ve also gotten to sit and watch a mother and baby bobcat along the river and that was just such a special moment.”
Parker said that if people have the chance to see an otter, they should enjoy the moment and avoid any interaction with them. Additionally, when walking in the river, they should avoid stepping on vegetation to keep the otters’ habitat healthy.
