MOBILE BAY, Ala. (WKRG) — Dozens of fishermen spot hundreds of dead fish floating in Mobile Bay over the weekend. The video has been shared dozens of times on social media. Now scientists are trying to figure out what happened.

Zipping along the mouth of Mobile Bay, Charter Boat Captain Blake Michaleski spotted hundreds of dead red drums along a tideline heading to the Sand Island Lighthouse Sunday. He posted the video online after the trip. It’s a worrying sight for anyone who loves the water.

“It’s how I make my living and it’s a catch and release species and you expect it to be here and to provide an experience it’s a part of fishing around Mobile Bay,” said Michaleski. The captain worried it could be a sign of a bigger problem.

“Could be a toxicity issue but what’s puzzling is that it affects one size of one class of fish,” said Michaleski. Officials with the Department of Natural resources, the Dauphin Island Sea Lab, and USA are all looking into it. They feel they’ve ruled out commercial fishing and it may not be an indicator of a larger problem.

“It’s scary to see that many dead fish, but there are other fish reproducing so right now we don’t think it jeopardizes the spawning stock population,” said Director of the School of Marine and Environmental Sciences at USA Dr. Sean Powers. He says likely culprits could be sudden low oxygen in the water or a harmful algae bloom–both naturally occurring but manmade pollution can also accelerate them. Most fish kills go unsolved.

Dr. Sean Powers, University of South Alabama: “By the time you get out and investigate the kill whatever happened because it was so rapid is simply not there anymore,” said Powers. Officials say it appears the overall health of the fish in the bay is good and anglers should be confident any fish that’s strong enough to take a bite on a hook is good to reel in.

Regardless of the cause of the fish kill, officials say it’s important for anyone on the water to document these things and report instances like this when they see them out in the water.

“We then get awareness we know this occurred we like to get details of where and what condition the fish are in and are there other factors they see,” said the Director of Alabama Marine Resources Scott Bannon. Officials say this is likely an annual occurrence, it’s rare though to see a fish kill like this in the water–we don’t usually find out about a fish kill until the carcasses are washed ashore.

We also reached out to Mobile Baykeeper who sent this statement: “Mobile Baykeeper is concerned and investigating this issue further, but we don’t have enough evidence currently to speculate on the reason for the fish kill. Citizens can report pollution issues, such as fish kills, at any time by going to www.mobilebaykeeper.org/report or by emailing patrol@mobilebaykeeper.org.”