The Making of a Dinosaur Fish

Imagine spotting a seven-foot long flash of gray armored with five rows of bony plates while you’re enjoying a summer day on the St. Lawrence River. At first, you might believe you saw a “sea monster.” Chances are you really saw a gentle giant that cruises along the bottom of our lakes and rivers sucking up aquatic insects, leeches, and zebra mussels.

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Lake sturgeon (Acipenser fulvescens) are New York State’s largest freshwater fish that predate the dinosaurs you and I never knew. Once a more common sight, these swimming fossils have unfortunately been one of many populations of fish to take a hit from human activities like overfishing, dam construction, and pollution.

Recognizing the threat of losing this important species from our waterways, the Service, New York State Department of Environmental Conservation (NYSDEC), and the St. Regis Mohawk Tribe’s Environmental Division have partnered up to bolster lake sturgeon populations. Each year, with the valued support of the New York Power Authority, there is an “egg take” event where the next generation of sturgeon is made.

Making a dinosaur fish is both an art and a science. Here’s how it’s done:

Step 1: Catch the fish

A few strong biologists go out in a boat with gill nets and capture adult lake sturgeon from the South channel of the Moses-Saunders power dam, where fish congregate to spawn each spring. With high water and faster flows than usual, this step in the process was more of a workout for the crew this year. Meanwhile, two staff are on stanby at the New York Power Authority’s dock to inspect the fish and determine whether they’re keepers for the egg take. At least four good adult females are needed in order to maximize the genetic pool of eggs.

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Biologists head out to collect adult sturgeon from the St. Lawrence River. Photo: USFWS.

After a tiresome stretch of weeks finding enough viable male and female fish, shuttling them into big blue holding tanks at the Power Dam, and constantly ensuring proper water quality and filtration, it’s time for the magic to happen.

Step 2: Massage the fish

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Biologists massage eggs from a female lake sturgeon. Photo: Justin Dalaba, USFWS.

It’s the day of the egg take. Water splashes as a biologist wrangles a female fish out of the tank. Eggs pour into a stainless steel bowl as another hand massages them from her white belly. A syringe of sperm is injected into water and poured over the eggs. Within 30 seconds to a minute, the eggs are fertilized. Shortly after, the milt mixture (as it’s called) is poured off and fresh water is added to reduce fertilization with multiple sperm.

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Mike Morgan (NYSDEC) adds the milt mixture to the eggs. Photo: Justin Dalaba, USFWS.

Step 3: The hand off

Like the passing of the torch, the eggs make their way down the assembly line from mother to fish-maker. It all happens so quickly and smoothly that you can see the years of experience these biologists have. Eggs are split between the NYSDEC Oneida Fish Hatchery and Wisconsin’s Genoa National Fish Hatchery, which will each raise their own brood of young fish for the fall stocking.

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Scott Schlueter and Doug Aloisi (USFWS) dividing eggs. Photo: Justin Dalaba, USFWS.

Step 4: Chair, feather, and clay

Now things slow down for a bit. The lucky contender will spend the next 30-40 minutes in a chair, rhythmically stirring the eggs, while adding Fuller’s Earth, Iodophor solution, and station water. Sturgeon eggs have an adhesive layer that allows them to stick to rocks and other substrate in the wild. But if they clump together in a jar, that could encourage fungal growth. To prevent that, the simple method of softly stirring the eggs with a turkey feather and clay seems to do the trick. The Iodophor kills any potential bacteria and viruses that may be on the eggs.

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Mixing in the Fuller’s Earth. Photo: Justin Dalaba, USFWS

Step 5: Sending the little ones on their way

Once proper de-adhesion and disinfection is achieved, the eggs are then packed up and sent off to their respective fish hatcheries, where they are expected to hatch within a week. Over the next few months, the newly hatched fish are fed a diet of brine shrimp, bloodworms, and krill until they are ready to be stocked in the fall. Of the nearly 130,000 fertilized eggs sent to the hatcheries, the hope is to produce 10,500 fall fingerlings this year.

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Fertilized eggs ready to be sent off to the hatchery. Photo: Justin Dalaba, USFWS

Step 6: Saying goodbye to their parents

After making their contribution to the next generation of fish that our grandchildren may get to see, the adult sturgeon are released back into the St. Lawrence from their holding tanks. Since 1993, New York State has been restocked with nearly 105,000 lake sturgeon through this multi-agency effort with supportive funding from the Fish Enhancement, Mitigation, and Research Fund. This is only a small part of a bigger effort to do what we can to save a living fossil.

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National Geographic photographer, Jennifer Hayes, films the release of an adult lake sturgeon. Photo: USFWS.


To learn more about this effort, be sure to check out The New York Times and North Country Public Radio articles.

3 Comments on “The Making of a Dinosaur Fish

  1. Happy to witness the return of the Sturgeon. Nice article Justin. David Marsh

  2. What an interesting, well written, and informative article. Thank you all so much for the wonderful work you all are doing.

  3. This is a fine article…this is a wonderful project. Mike Morgan and his crew are in the front of the conservation and rescuing efforts! Proud of them!

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