Fishing Dreams and Working Realities

I knew it would be a fantastic day when I hooked up the trailer and every light worked. All the wiring patches and troubleshooting had paid off. No wasted time laying in the driveway chasing wires – I was off to the bay! Oh wait, I am not on vacation… I work for a Texas Parks and Wildlife Department coastal fish hatchery.

I dreamed of motoring away from the boat ramp, leaving everyone and everything behind except peace and big fish. In reality, it was my day to measure water quality parameters and feed tiny pellets to juvenile Red Drum and Spotted Seatrout in our rearing ponds. After that it was on to mowing, tractor maintenance, and getting gear lined out for a fingerling harvest tomorrow morning. Tomorrow I will catch and release tens of thousands of fish from my stocking trailer.

I used to work at a public aquarium where the aquaculture was intense, and we were constantly fighting nitrogen (the most common fish waste is ammonia - NH3 that is respired off the gills) and phosphorous in our exhibits. Those seemingly malicious substances grew algae, causing us to have to continually scrub the walls and filter the water. Conversely, at the fish hatchery, I had to learn how to fertilize ponds by adding inorganic fertilizers (nitrogen and phosphorous) to stimulate phytoplankton (microscopic algae that are the basis of the food chain) blooms. The phytoplankton, coupled with organic fertilizer (cottonseed meal), feed zooplankton (microscopic animals) that are then used to feed the young fish.

Although Texas Red Drum adults typically live in Gulf of Mexico water with 32 – 35 parts per thousand (ppt) salinity, they are considered euryhaline and can tolerate a wide range of salinities. They are found in high salinity water (> 40 ppt) where evaporation exceeds freshwater inflow (e.g., the Upper Laguna Madre), brackish (0.5 ppt to 32 ppt) bays and estuaries where freshwater and saltwater meet and can even survive in freshwater (<0.5 ppt). Being euryhaline is an adaptive advantage for Red Drum because it allows them to take advantage of the highly variable coastal bays and estuaries, navigating to where abundant food exists. It also makes Red Drum an ideal species for aquaculture purposes because of its wide tolerance for fluctuations in water quality.

I love to chase trophy fish because they are fun to catch. Trophy fish are often fecund females because they have a larger body mass that helps them produce and carry large numbers of eggs. While some offspring will not survive to reproduce, it is all a numbers game – produce enough eggs and some fish are bound to survive for the next generation. The hundreds of millions of eggs produced in hatchery brood stock tanks also add more genetic diversity to the population, which is critical to a species’ survival. Large, diverse gene pools allow more organisms to survive whatever nature throws at them, such as disease and changes to their environment. Let’s hope it helps with whatever climate change throws at them as well.  

Similarly, in the hatchery program we stock 20-30 million fingerlings into Texas public waters each year to ensure sufficient numbers are present for future anglers. Survival varies from year to year and bay to bay depending on many factors. But on average, research has shown that approximately six percent of fishable Texas Red Drum are hatchery fish. This was determined genetically by researchers at TAMU in College Station, and results were pooled over a number of years.

In the Gulf of Mexico, Red Drum spawn from mid-August through mid-October. In hatcheries, Red Drum brood stock are kept in large tanks that are light and temperature controlled. Manipulating light and temperature allows the hatchery to simulate the natural conditions required to induce spawning and take advantage of productive summer temperatures and conditions in outdoor fingerling grow-out ponds. I change the season as far as the fish are concerned. I feel like Mother Nature, or Father Time.

Hatchery raised fish get a jumpstart on their wild brethren, entering protective bays directly and avoiding many of life’s early, open-water threats instead of passively drifting where currents carry them, which is hopefully into the same bays.  This is a well-known wildlife conservation strategy called “HeadStarting” and is commonly used in sea turtle conservation. Fish are harvested and stocked at 35 millimeters total length (approximately an inch and a half) and are called fingerlings – although I argue it takes two to equal my finger. This size is an appropriate compromise between protecting fish through highly vulnerable, early life stages and maintaining our logistical ability to raise and release 15 million of them for enhancement purposes.  

All in all, giving up a day’s fishing to work at a hatchery is very rewarding. Considering the Texas Parks and Wildlife Department’s Coastal Fisheries Hatcheries produce fingerlings in such staggering numbers that in 2021, we surpassed 800 million fingerling Red Drum stocked in Texas bays and estuaries. This, combined with other traditional management strategies such as bag and size limits, has brought Red Drum numbers back from the 1970s low to the world-renowned fishery it is today!