dead sturgeon

What to do if you spot invasive species, dead fish, or algae blooms

You can help protect the river’s ecology

Invasive species are species from other parts of the world that have been accidentally introduced into New York State and have flourished, often challenging the ability of native species to compete. Common invasive species in the Hudson River are water chestnuts, didymo, hydrilla, zebra mussels, and grass carp.
Both Atlantic and shortnose sturgeon are protected by the Endangered Species Act. If you find a dead sturgeon, do not touch or move it. For dead sturgeon or significant numbers of other fish species, Take photographs and careful notes, and report it to each of these entities:
  • Specific location where fish was found
  • Condition of the fish. Note if it is badly decayed or freshly killed.
  • Signs of trauma, and where the signs of trauma appear on the fish.
  • Length of fish, from nose to tip of upper tail fin (estimate length if you can‘t measure).
  • Look for external tags affixed for scientific research, usually a yellow streamer at or near the base of the dorsal fin. Take note of any writing on the tags.
  • Check the left pelvic fin. If it is clipped, it may have been marked by scientists for research.
  • Take a picture of the entire fish, take pictures of any injuries, and take a picture of the head and mouth, from below. (This will allow for proper identification of the species.)
  • Leave the fish where it was found. Possession of endangered species is not allowed.
An algal bloom is a thick layer of algae that forms when algae or algae-like bacteria overgrow in water. Usually they form because of excess nutrients in the water. Some blooms, known as “harmful algal blooms” (HABs), produce toxins that are dangerous to fish, animals, or humans.
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It’s difficult to tell by looking at a bloom whether it is a HAB, but some things to look for are:
  • bluish, green-brown, or reddish coloring
  • a layer on the surface of the water that looks like paint or soup
  • visible scum or bubbling foam
  • spires, mats, or blobs
  • a fishy, septic, or gasoline smell
Plants and non-toxic algae are usually green, yellow, or brown. They smell leafy or neutral when they are healthy, and may smell musty when they are dying or dead, but they’re still safe. These kinds of organic life in or on the water are normal:
  • Plants that are rooted or floating
  • Algae that looks like plants or filaments
If you suspect a HAB, avoid swimming, boating, or playing in the water, and don’t drink it. in or drinking water with a bloom. Take photos and report it to DEC using the Suspicious Algal Bloom Report Form or email HABsInfo@dec.ny.gov.