Delaware Public Media

Delaware scientists launch tech to alert fishermen of endangered sturgeon

Apr 13, 2018

A team of First State scientists has developed a text alert system that can inform fishermen of the presence of endangered Atlantic Sturgeon in the Delaware Bay.

Polar orbiting satellites from the National Oceanic and Atmospheric Administration and NASA take measurements of the Delaware Bay and send them to the University of Delaware.

University of Delaware and Delaware State University scientists have developed a statistical model that makes predictions for where sturgeon are in the bay and their depth based on historic satellite observations of tagged sturgeon and current water conditions like salinity. The researchers say the system has 88 percent accuracy.

Delaware watermen are not allowed to harvest sturgeon, which have been listed as endangered under the Endangered Species Act since 2012. UD oceanography professor Matt Oliver says one concern is they could accidentally catch the endangered fish while targeting other species.

That’s why watermen could use an alert system.

“When they’re out there, they aren’t fishing for these things. They want to avoid them, they end up damaging their gear, and the text alert system specifically is small enough, compact enough for them to interact with while they’re out on the bay,” Oliver said.

The satellite system generates daily data. Oliver says it’s up to the Division of Fish & Wildlife to determine when to send out alerts to fishermen.

“If the fishermen know their general location, if they’re in the river, the upper bay, the lower bay, and they know their depths, then they know their risk of encounter,” Oliver said.

They aren't fishing for sturgeon. They want to avoid them. -Matt Oliver

Oliver worked with UD post-doctor researcher Matthew Breece as well as DSU natural resources professor Dewayne Fox and Delaware Division of Fish & Wildlife’s Ed Hale to create the alert system and communicate with fishermen. 

Hale, a biometrician with the Division of Fish & Wildlife, ships the sturgeon forecast system out to fishermen in real time to help them avoid the endangered species and still perform their own fishing operations.

He says the scope of the sturgeon bycatch problem is something scientists have struggled with as their numbers have decreased since the 1990s, but there isn’t a requirement to track the species. Historically, these fish existed in high numbers, peaking at 7.5 million pounds coastwide in 1890, Hale said.

From 1999 to 2011, the state collected information on interactions with sturgeon that fishermen submitted voluntarily. In 2007, the state saw a high point of 122 reported in the Delaware Bay and Delaware River. The following year, they heard of only seven. 

The program was terminated due to low participation rates.

But anecdotal evidence from fishermen that sturgeon have been seen jumping in lower Delaware Bay makes the alert system useful, Hale said. 

Delaware Division of Fish & Wildlife Biometrician Ed Hale holds a juvenile Atlantic Sturgeon on a boat in the Delaware River.
Credit DNREC

“We’re trying to really demonstrate that by avoiding them, you can also avoid time spent de-tangling them from your gear,” Hale said. “It was a win-win essentially for both the endangered species as well as sustainable fishing practices.”

Between April and May, adult Atlantic Sturgeon move into Delaware Bay to spawn in rivers. Sturgeon below age 1 tend to stay in the lower river and move down into the estuary until they’re age 2, Hale said. Then they tend to explore outside of their home estuaries.

“It’s believed that these fish kind of move around and mix around the coast, there’s some offshore movement. And once they’re reproductively capable they will return,” Hale said.

The scientists launched the technology earlier this week. Almost 20 people have subscribed so far.