Got a fish health question?

Two southern flounder. One with the typical white underside (right) and the other with almost full pigment on the right side. Looks like mother nature remembered at the last minute and shortchanged the head. Photo: Capt. Ralph Allen
Gulf flounder have a pigmented left (upper) side and a white right (under) side. In this photo both flounder are displayed on the right side. Looks like mother nature remembered the right side should be white at the last minute in the flounder on the left, and stopped painting just before reaching the head. Photo: Capt. Ralph Allen

Every so often I receive photos taken by anglers who have observed fish abnormalities while fishing. The typical question I get is, do you know what this is? If not, can you help me find someone who does? Regardless of whether or not I know the answer, my response is always the same; report it to the Florida Fish and Wildlife Conservation Commission’s (FWC) Fish Kill hotline. But the fish isn’t dead! It’s OK, FWC’s Fish Kill hotline is maintained by their Fish and Wildlife Health section (FWH), and that section is also interested in fish abnormalities.

Having all fish abnormality reports go to one spot is good for the fishery. It allows scientists to quickly identify immerging issues and respond with management strategies to protect our fishery resource.

Fish abnormalities include lesions, parasites, tumors, skeletal deformities, and a whole host of other things. Recently, I reached out to Micah Bakenhaster, a fish health expert with FWC’s FWH section and asked him to answer a few questions I thought readers would be interested in. His responses are below.

1. What does the FWC FWH section do and why?

The FWC Fish and Wildlife Health research group monitors the health of wild fish populations, conducts basic and applied research on fish pathogens, and tracks fish kills with the aim of providing information and appropriate response to public concerns about aquatic animal health and disease.

Blacknose shark with nematode eggs on belly caught in Charlotte Harbor. Capt. Ralph Allen Photo
A blacknose shark with nematode eggs on its belly, caught in Charlotte Harbor and reported to the Fish Kill Hotline by Capt. Ralph Allen. Photo credit same

2. What are some common fish abnormalities? (genetic, parasitic, etc.)

Parasites are perhaps the most commonly encountered abnormalities in wild fish populations; although, they are rarely associated with significant disease. As a general rule, other abnormalities such as skeletal deformities, fin rot, ulcers, and tumors are relatively rare but they are expected to occur in a small portion of a healthy fish population.

3. What’s the most bizarre abnormalities you have encountered?

I would be hard pressed to choose a particular type of abnormality as most bizarre, from isopod parasites living in the mouths of fish to a fully grown eyeless snook to a parasite infection so intense that the fish seems to have a tumor. Fish can be amazing survivors, tolerating conditions that would seem not survivable to humans.

4. What are some of the causes for fish tumors or lesions?

Although many people use the term ‘lesion’ to refer to ulcers (deep, open sores) it actually includes a wide variety of abnormalities such as tumors, fin rot, and skeletal deformities, all of which can have many causes including biological pathogens such as bacteria and fungus and non-biological ones such as chemical contaminants. It can be very difficult to determine the cause of a lesion, and frequently they are the result of multiple interacting factors.

Shrimp with parasitic masses found in Indian River Lagoon 2005 - FWC Photo
Anglers in the Indian River Lagoon alerted FWC to shrimp with parasitic masses in 2005 – FWC Photo

5. Can you give an example of a time when angler reporting provided an early warning to an environmental health problem?

We depend on anglers to help us recognize when and where abnormalities are unusually common or severe. Anglers and other concerned citizens were responsible for notifying us about an outbreak of fungal disease in fish from the St. Lucie and Caloosahatchee Rivers in the mid-90’s. The reports coincided with releases of large amounts of fresh water from Lake Okeechobee and ultimately helped us to promote the use of staggered water releases by the Army Corps of Engineers to minimize the problem.

6. What are some common causes of fish kills?

Algae blooms are the most common cause of fish kills in Florida. These include red tide in the Gulf of Mexico and other types of blooms that occur frequently in brackish and freshwater estuaries and ponds. Some, like red tide, are capable of producing toxins, but all have the potential to use up oxygen in the water to the point that fish and other animals can suffocate.

7. Anything else you want to share?

The FWH group has been working on a wildlife reporting app that will be released later this year. It will allow the public to submit a variety of reports regarding wildlife disease and mortality (aquatic and terrestrial animals), nuisance animals, animal sightings (e.g. lionfish, exotic species, panthers, etc.), and more.

How to report fish kills and/or fish abnormalities – Anglers can report fish kills and fish abnormalities by calling the Fish Kill hotline at 1-800-636-0511. When reporting over the telephone it is important to include the following in your message: 1) the location and the type and number of fish involved; and 2) a mailing address and a phone number or e-mail address so Fish and Wildlife Health staff can call back if they need more information. Anglers can also report fish kills and fish abnormality by submitting an online report at the following website:


Posted: August 15, 2016

Category: Coasts & Marine, Natural Resources
Tags: Fish Health, Fish Kills, FWC, Lesions, Parasites, Tumors

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