Red tide, dead zone, toxic bloom: These environmental events are different, but they have one thing in common—they are caused by algae blooms. Harmful algal blooms, or HABs, occur when colonies of algae, simple plants that live in salt and fresh water, grow out of control producing harmful effects for people, fish, shellfish, marine mammals and birds.

Harmful Algae is a Growing Concern Among Anglers and Environmentalists

It is important to understand that not all algae blooms are harmful. In fact, most algae blooms are beneficial. Algae is a major source of energy that fuels the aquatic food web.

However, a small percentage of algae produce powerful toxins that can kill fish, shellfish, mammals, birds and cause illness in people. HABs also include blooms of non-toxic species that have harmful effects on aquatic ecosystems. For example, when masses of algae die and decompose, the process can deplete oxygen in the water forcing animals to leave the area or die.

a beach covered in dead fish killed by toxic algae blooms
Harmful algae blooms can kill fish and sicken people. Check with state and federal agencies before fishing an affected area. | Feature photo: Jinlide/Dreamstime

HABs have been reported in every U.S. state and they’re on the rise. They often occur when warm water mixes with excessive nutrients, especially phosphorus and nitrogen, which are found in animal waste and fertilizers. Drought and climate change make the problem worse—harmful blooms grow thicker and faster when water levels are low, temperatures are high and water is stagnant.

Some HABs are visible as thick mats or scum on the surface of the water. The blooms can appear bluish-green, bright green or even red. Red tide is one of the most well known HABs in the U.S. that occurs nearly every summer along much of the East Coast. This bloom, like many HABs, produces toxins that kill fish and make shellfish dangerous to eat. The toxins can also make the surrounding air difficult to breathe.

What About Fishing?

Before heading out on the water, check state and local health agency websites for warnings and maps. Human illnesses caused by HABs, though rare, can be serious or even fatal. A 2016 toxic bloom on Utah Lake caused more than 100 people to report vomiting, diarrhea, headache and rashes.

Situations to avoid include strong green or dark green water, the presence of observable floating chunks or surface scum. If there is an offensive odor or stench, move to a different area.

No one knows for sure whether eating fish caught from affected waters is a health risk. There have been no reports of people becoming sick from eating fish caught during a bloom but there has been no definitive research regarding the risk to human health. The best advice is to play it safe.

Algae Advice

The New York State Department of Environmental Conservation offers the following advice about algae blooms:

  • If you see it—avoid it.
  • People, pets and livestock should avoid contact with water that is discolored or has algae scum on the surface. If contact does occur, rinse the area thoroughly with clean water to remove algae.
  • Seek medical attention immediately if symptoms such as vomiting, nausea, diarrhea, skin, eye or throat irritation, allergic reactions or breathing difficulties occur after having contact with blooms or untreated surface water.

Cover of the Kayak Angler Magazine Spring 2017 issueThis article was first published in the Spring 2017 issue of Kayak Angler Magazine. Subscribe to Kayak Angler Magazine’s print and digital editions, or browse the archives.


Harmful algae blooms can kill fish and sicken people. Check with state and federal agencies before fishing an affected area. | Feature photo: Jinlide/Dreamstime

 

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