Growing up among so much beauty I would find myself asking, “Who put the fish in the lakes?” Once again faced with a “Chicken and the Egg” dilemma, I put it down to Mother Nature and natural progression.
In this case of the “Fish and the Egg,” I would find my answer 15 years later with Colorado Parks and Wildlife (CPW) Aquatic Biologists. These awesome biologists do everything from managing habitat to monitoring water conditions, figuring out fish populations, and protecting our native fish from invasive species and pollution as “all in a day’s work.” Come rain, sunshine, snow or high winds, our biologists are out there helping our wildlife survive and flourish.
I have learned that some fish in our lakes need our help. The walleye in some lakes cannot reproduce easily as the waters have silt in them. This silt interferes with egg fertilization, inhibits oxygen uptake by the eggs, and affects the numbers of eggs hatched, resulting in reduced populations.
This year I decided to volunteer for the Walleye Spawn Operation, which runs between March and April every year. It was the most satisfying thing that I could have done from 7 a.m. to noon on a Saturday morning. My dad woke me up at 6 a.m. with just enough time to dress warm, grab a bite to eat and drive to Cherry Creek Reservoir. At 7 a.m. (which was still too early for any teenager), the rising spring sun had just started to warm up the earth. The cool breeze lingered lazily helping to wake me up from my early morning daze.
We made our way across the marina dock to the CPW spawning barge and introduced ourselves to a friendly group of volunteers, biologists, and CPW wildlife officers. Our mission was to help collect eggs that would contribute to a statewide goal of 139 million walleye and saugeye eggs. These eggs would be shipped to other states to trade for other fish species, or hatched in Colorado hatcheries to be stocked as fry, or to grow into fingerlings for stocking. These fish would be introduced to lakes and grow into big game fish for anglers like me all around the country.
The hard but highly rewarding work started almost immediately after we all got together on the dock. We put on float coats, a must for everyone. Six of us got into a boat and sped out to the dam area of the lake where the gill nets were set the night before. It is such an amazing feeling to be the first on the lake with mist on the water. The boat ride was exhilarating! The crisp cold air on your face made you feel so alive. Nothing beats skimming over the sparkling water at 30 mph in a sleek aluminum hull “Clark” boat with a Mercury Diesel 2.8L outboard motor putting out 220 horses on a quiet Colorado spring morning.
As we neared the dam, you could see the floating orange marker buoys. The evening before, our biologists had set out gill nets near the rocks. This is traditionally where walleye came to spawn and they would swim unknowingly into the nets and get caught.
We started at the first net and pulled in the first few yards and then one fish came popping out of the water flailing. One of the biologists tossed me a pick and showed me how to untangle the fish from the nets. After he did a few, I decided to give it a go. I grabbed the next fish, held it close and started picking/pulling the net strings off the fish body. As I held and freed the fish, he told me to release it carefully back into the water. I saw it come back to life and disappear into the deep green water.
We unloaded the nets on the dock and sorted the fish into holding tanks at the spawning barge. Walleye are categorized and separated into groups- ripe females that are ready to spawn, green females that not yet ready, and males. The female Walleye that are spent (have already spawned and do not have eggs in their belly) are released immediately back into the lake. Every fish is listed by these categories and carefully documented. As needed, some walleye are also tagged with an electronic chip and clipped for identification.
The data that is collected from these trips are carefully analyzed. The numbers give a detailed trend of what is happening in the lake. Are more fish coming to spawn? How big are they? After being tagged, can they be identified again as a producing adult fish? This was almost like Facebook data mining that the fish had no idea about. The biologists could read this data like a map and decide when and where to put out nets. They could project quite a few details on fish mortality and maturity based on these pieces of carefully documented data.
My mentors showed me how they take a female and gradually press her belly to express the eggs into a spawn pan. Then they do the same for a male to get the milt, mix water to activate the sperm and fertilize the eggs. Finally, they add bentonite mud into the spawn pan. This creates a light coating around the fertilized eggs to make sure the eggs don’t stick together or clump up. By stirring the eggs combined with mud and water with a goose feather for 90 seconds, it was possible to increase the natural survival of 30% to a 50-90% rate of survival at a hatchery. This amazed me to think that most of the fish we caught from lakes like Chatfield and Cherry Creek were only possible due to nurturing work done by hatcheries and by the efforts of biologists and volunteers. A lot of things such as walleye in the lakes are taken for granted. It is only possible due to these stewards of wildlife who willingly give their time and effort to support conservation.
The final count for the 2018 Walleye Spawn Operations was 116,202,732 green eggs. No more eggs were taken as the survival rates from eggs to fry at the Pueblo Hatchery and Wray Hatchery were really high.
In every opportunity where I have interacted with our biologists and wildlife officers, I have learned so much about our ecosystem and what goes into making our outdoors so vibrant and bountiful. I look forward to my next opportunity to volunteer with CPW and be a steward for our wildlife.
Written by Shiv Ghosh. Ghosh lives in Highlands Ranch and is an Eagle Scout and avid outdoorsman.