Article for March - April 2009
"My Mother Is A Fish"
by Elizabeth Renedo
Unlike the famously confused character who uttered those words in William Faulkner’s As I Lay Dying, the narrator of this account of the life and times of a hatchery-raised striper really does have a fish for a mother.
You know, it wasn’t until I was released here in Lake Murray that I began to realize how good I’ve had it. Some of these fish—the ones that have had to grow up exposed to the elements—have a lot more battle scars than I did at their age. Me, I'm a hatchery-raised striped bass—or, just plain "striper" to those in the know—born to, well, not privilege exactly, but let’s just say I’ve enjoyed a certain level of TLC to give me a good start in life. Here’s my story, as best as I can piece it together.
All of us Lake Murray stripers have a similar version of the story that somehow sticks with us from our very beginnings. That’s because, just like the striped bass that fishermen pull out of lakes Hartwell, Thurmond and Wateree, we all started out at the same place—the state Department of Natural Resources’ Jack D. Bayless Fish Hatchery in Bonneau. Let me tell you, the hatchery is a great place to grow up. Most of the stripers in lakes Marion and Moultrie are also born there, though these Lowcountry lakes do support some natural reproduction of striped bass, as well. In fact, the hatchery produces as many as 16 million striped bass fry in an average season, so they know what they’re doing.
But wait, I’m getting ahead of myself. Let me start at the beginning, with my parent fish. I don’t know who they were exactly, but I do know something of their story. I’ve learned from several of my older neighbors how biologists and technicians from the hatchery collect the very best male and female stripers they can find to serve as brood fish for creating the next generation. When they tell about their experiences, the former brood fish can’t help but swim with a proud spring in their stroke. You see, the folks from the hatchery don’t take just any fish.
In the early spring—late March and April—the Bayless Hatchery crew gets to work searching out the most mature, healthiest female stripers and the biggest, healthiest males to serve as their brood stock. Striped bass are sexually mature by five years of age, with females reaching peak egg production at around age eight, so the hatchery technicians look for fish in this age range, though they sometimes select fish closer to four years when they have trouble finding brood stock. Brood stock can be tough to come by in years of drought, when little water is released from South Carolina’s reservoirs.
The process for catching brood stock is a bit startling to the fish, but not painful or dangerous. Hatchery crews use two boats to catch their brood stock. One is equipped with special equipment that puts an electrical current into the water, shocking all the fish within about a ten-foot radius. The other is a “catch boat,” a regular boat with a special railing near the front that allows an eagle-eyed technician to safely stand in the front of the boat and scoop up the stripers—often real bruisers weighing upwards of five to ten pounds or more—without losing his or her balance and falling into the electrified water.
The mild shock causes the fishs’ muscles to spasm, propelling them to the water’s surface. When a good brood stock candidate surfaces, the excitement begins, with the catch boat zigging and zagging furiously to get close enough for the net-wielding technician to scoop up the fish before it recovers from its shock and returns to the depths. The whole process is quite impressive, with the technicians spotting, scooping and deciding whether or not to use the fish for spawning and either releasing them or placing them in the catch boat’s live well, all done in a matter of seconds, while simultaneously bobbing and maneuvering on the water.
Once they’ve rounded up the fish they need, the hatchery crew heads back to the landing and loads their lucky brood stock into a special tank truck, which is equipped with two oxygenated cooling tanks designed to give the fish a safe and comfortable ride back to the hatchery.
After the freshly caught brood stock arrives at the hatchery, the real work begins. First, the lucky parents-to-be are weighed, then they’re placed in outdoor holding tanks where they’ll live for the next few days until their spawning is complete. The water in the tanks is circulated and oxygenated using a special pumping system and is slightly saline, which helps to keep the stressed fish healthy by preventing the salt in their bodies from leaching out. The males are held together in one big tank and the females are placed one or two to an individual compartment within another big tank. This helps the hatchery staff tell the females apart, and makes them easy to catch when they need to work with them.
Shortly after their arrival at the hatchery, the female stripers are given an injection of hormones that triggers the ripening of their eggs. Hatchery staff monitor the females closely as their eggs ripen, a process that takes about 30 hours to complete. Once the eggs are ready, they only remain viable for about half an hour.
When a female’s eggs are ready to be fertilized, the pace gets pretty hectic around the hatchery. First, she is netted out of the water and her cloaca plugged to prevent the loss of any of her valuable eggs. Then she’s placed into a hammock of sorts. The hammock hangs down into a tank that contains an electrode, which emits an electric current into the water. This small dose of electricity anesthetizes the female so she will be relaxed when the technicians strip her eggs.
The action starts as soon as she’s out of the hammock. One technician holds her in position above a plastic basin, and another removes the plug and presses her belly, moving his or her hands downward toward the tail. This causes her eggs to squirt out into the basin. Once all her eggs are stripped, the technicians return the female to the holding tank and immediately begin to net up three males. The males are anesthetized with electricity one at a time and then stripped of their sperm using the same method as when the females are stripped of eggs. As soon as the sperm is in the basin with the eggs, a technician adds fresh water and begins to stir it all together as gently as possible, using a turkey feather. After a few minutes of stirring, the eggs are allowed to settle and the technician pours as much water as possible out of the basin.
Somewhere in this whirlwind of a spawning process, three fin clips—tiny snippets of fin—are cut from the mother fish and all three males, then placed in sample tubes, numbered and recorded. This enables fisheries biologists to identify the hatchery-raised stripers (like me!) when they’re caught later. The genetic identification system is so exact, they’ll be able to tell not only that a fish was produced at the hatchery, but also what day and hour that fish was spawned, and exactly which pair of parent fish spawned it.
When stripers spawn naturally, they travel up rivers to do so, and the fertilized eggs bump and swirl through the water as they flow downstream. This bouncing motion is required for the eggs to develop into fry. That’s why stripers that live in reservoirs or river systems inhibited by dams cannot spawn naturally—any eggs that get fertilized sink and die without sufficient streamflow to keep them moving.
The hatchery answers this need with an innovative system of tall glass jars with water constantly piped in from above. After the water is poured off the freshly fertilized eggs, the technicians rush them inside and measure them out into the jars, carefully recording the jar numbers for their records. The water pouring in from above keeps the eggs stirred up as if they were traveling down a stream toward the sea. The fertilized eggs begin to plump and turn clear, an indicator that they’re beginning to develop.
After just three hours, hatchery staff draw a sample from each jar to check the fertilization rate, which can vary wildly—50 percent fertilization is very good, but the eggs of a female in her peak of sexual maturity can have fertilization rates in the nineties. The eggs churn in the jars until they begin to hatch, and the newborn fry swim over the tops of the jars and into glass tanks where they hang out and eat brine shrimp for their first two days of life. After two days, the fry are transferred to larger tanks inside the hatchery, where they spend another five days eating to their hearts' content.
At one week old, the fry are carefully poured into insulated boxes lined with plastic bags. The savvy technicians eyeball the bags and divvy up the fry so there are about 50,000 in each bag. Some of the fry are transported in these insulated vessels to the Orangeburg National Fish Hatchery, where U.S. Fish and Wildlife Service staff tend them in ponds until they’re ready for stocking. The others, bound for the state DNR's Dennis Center Hatchery, are put into tank trailers specially designed by Forrest Sessions, the Bayless Hatchery’s manager, and his skilled staff.
The fry spend the next 35 to 42 days growing fast in the ponds at each hatchery on a diet of zooplankton. Once they’ve grown into fingerlings, they're ready for stocking around the state. Many fish are stocked from tank trucks at the water’s edge, but recently, more and more stripers are stocked from boats into deeper water. This gives them a better chance of survival because the deeper water contains fewer predators.
So, now you know what I mean when I said I had an extra good start in life. It still amazes me that millions of stripers—almost all of us, it seems—were lucky enough to grow up this way. Who knows, maybe in a few years I’ll be selected for brood stock, bringing this hatchery-raised striper’s life full circle. .
Elizabeth Renedo would like to thank Forrest Sessions, Brian Grooms, Kim Hughes, Doug Cooke and the rest of the brilliant Bayless Hatchery staff for all of their help and for showing her the best fish-squeezin’ good time she’s had in a long while.
© 2009 South Carolina Wildlife Magazine, March - April 2009 - www.scwildlife.com