A group of divers who spend their weekends on Lake Travis is trying to raise public awareness about a dramatic increase in invasive zebra mussels they’ve seen in the lake over the past year. 

The unwanted mollusks were first confirmed to be in Lake Travis in July 2017. At that time, Texas Parks and Wildlife declared the lake infested with a population that was reproducing because different sizes and ages of zebra mussels were found at two different sites on the lakes.

But Matt Jacobs, a dive instructor with Dive World Austin, said that it’s not just the fact the mussels are there that’s concerning: it’s the rate at which they’ve spread around the lake.

“Six or eight months ago, it was very rare to see, you’d pick up an object and maybe there would be one or two,” Jacobs said. “But now there are entire areas that are just covered with zebra mussels and they are spawning and spreading unbelievably quickly.” 

The mussels come with a host of problems: they block pipes, ruin shorelines, hurt native aquatic life, damage boats, make cleaning more expensive and make lake floors or rocks too sharp to walk on. 

Because of these sharp rocks, divers will likely have to wear more covering. Jacobs said he’ll need to have two sets of diving equipment, one for going in zebra mussel-infested waters and one for going in places where the mollusks haven’t spread. 

Their larvae are microscopic and can survive for days on boats if water isn’t drained properly. Jacobs is trying to get the message out to remind both regulars on the water and people who’ll be visiting Lake Travis for the first time that they all play a role in preventing the spread to other waterways. 

“There are really environmentally sensitive areas around here and if you aren’t careful, you’re gonna be the person responsible for spreading the zebra mussels,” Jacobs said. 

Robert Weiss, the owner and operator of Lake Travis Scuba, also said that he had never seen these zebra mussels on the lake until this year. He and the divers he works with take time to clean their equipment and drain water after trips to make sure they’re not spreading the mussel larvae. 

“They’re here, they’re here to stay, its just a matter of dealing with them,” Weiss said. 

Zebra mussels were first spotted in Texas in 2009. 

Texas Parks and Wildlife has been trying to spread the word that while these mussels can spread downstream, they can be spread even more quickly being transferred from one body of water to another by people who don’t wash their boats properly. 

Boaters are legally required to drain all of the water from their boat and anything on board before leaving or heading to another freshwater body.  Then they have to clean and dry their boats. 

The rules apply to all types of boats — from motorboats to kayaks — and a first violation can lead to a fine of up to $500. 

Texas Parks and Wildlife recommends all boaters remove their drain plugs and pump out as much water as possible from ballast tanks, bilges and livewells before leaving or heading to any fresh bodies of water. Carefully cleaning and drying gear, including swimsuits, wetsuits and water shoes can also curb the risk of spreading mussels. 

“There are more than 1,500 boat ramps in Texas and we can’t be everywhere, so we have to rely on boaters, marinas and concerned citizens to help in this fight,” said Texas Parks and Wildlife’s Invasive Species Lead Monica Garrity to KXAN back in 2017. 

In August 2017, the zebra mussels were found in Lake Austin as well. Austin Water told KXAN this had them increasing inspections to make sure their pipes weren’t getting clogged by the mussels. 

Merdad Morabbi with Austin Water explained to KXAN in 2017 that too many of those mussels could create taste and odor issues and can have a “domino issue impact on the environment.” 

By February 2018, TPWD had seen enough mussels to conclude that Lake Austin was infested with them. 

Zebra mussels were found in Canyon Lake in the summer of 2017. In November 2017, Lake Georgetown was found to have zebra mussels as well. TPWD said it was an example of how quickly zebra mussels can come into an area because as recently as spring 2017 all plankton samples from that lake had tested negative for zebra mussel larvae.