Trinity River crucial to striped-bass fisheries
A pair of rituals performed on a short stretch of the Trinity River immediately below the Lake Livingston Dam each April for more than 30 years play crucial roles in maintaining one of Texas’ most popular freshwater recreational fisheries.
“This is where every striped bass and hybrid bass produced in our hatcheries and stocked in Texas lakes gets its start,” Craig Bonds, director of inland fisheries for Texas Parks and Wildlife Department, said Tuesday as he stood on the west bank of the river. “It all depends on this.”
Bonds and more than 20 inland fisheries staffers had gathered on the edge of the Trinity for a ritual Texas fisheries crews have executed each spring since 1981, setting up tanks and tents and tables, positioning trucks and water-filled trailers, and prepping specially equipped boats designed to send pulses of electricity into the water around the vessel.
A couple of hundred yards upstream, about 7,000 cubic feet of water per second — more than 3 million gallons each minute — sluiced down the face of the dam’s spillway, pouring along the tailrace before plunging over a rocky berm to a roar of roiled water and spray.
The other ritual — and the reason for the first — was playing out in that cauldron of churning water. Adult striped bass crowded in the aerated current. They were there to spawn. An early April ritual
In early April each year, when a combination of water temperature, photoperiod and river flow triggers the fishes’ immutable drive to procreate, adult stripers in the Trinity River push upstream, congregating in the cool, fast-flowing aerated current at the edge of the tailrace. Adult females, most weighing 10 to 20 pounds but some larger, carry developing masses of eggs — as many as a million in a 20-pound fish.
When those eggs are ready, she releases them as attending males fertilize them. The fertilized eggs are carried downstream, suspended by current, until they hatch 36 to 75 hours later, and the next generation of striped bass begins.
This natural reproduction of striped bass occurs with any frequency in only two places in Texas — the Red River upstream of Lake Texoma and the Trinity River below Lake Livingston. The Trinity is the only place where fisheries managers have reliable access to heavy concentrations of spawning stripers. And Texas fisheries biologists need to collect some of those fish to use in the hatchery program that annually produces the millions of striped bass and striped/ white bass hybrid fry and fingerlings that are stocked into Texas waters to support what is the fourth-most popular game fish among the state’s 2 million-plus freshwater anglers. It is a fishery almost wholly dependent on hatchery-produced fish.
Striped bass are not native to Texas. At least they aren’t native to Texas inland waters. North America’s native striped bass are anadromous fish, living most of their lives in coastal marine waters but migrating to freshwater rivers to spawn. Stripers’ historical native range centered along the Atlantic coast with modest populations documented as far into the Gulf of Mexico as Corpus Christi Bay. That historic range dramatically shrank early last century, with striped bass vanishing from Texas coastal waters by the 1940s.
But a bit of serendipity put striped bass back into Texas, this time wholly in inland waters. In 1942, dams on South Carolina’s Santee and Cooper rivers trapped spawning striped bass in the resulting reservoirs. To the surprise of fisheries biologists, the land-locked stripers survived and even flourished in the reservoirs.
Rivers flowing into the lakes provided sufficient spawning habitat. The deep, open waters of manmade reservoirs, all but useless to largemouth bass and crappie and other native fish tied to littoral habitat, proved a suitable substitute for the open coastal waters that adult stripers had called home. The clouds of threadfin and gizzard shad that exploded in the nutrient-rich open waters of the lakes proved perfect forage for the schools of stripers roaming those expanses. The open-water predators fit an unfilled niche in the newly created fisheries. New homes for stripers
Fisheries managers quickly learned how to artificially spawn stripers in hatcheries and began stocking the fish in some of the scores of new reservoirs created during the decades-long lakebuilding frenzy that began in the 1950s and peaked in the 1970s. In some lakes, those populations thrived, and anglers took to the big, strong, hard-fighting striped bass in a big way. How big? A decade-old study on Lake Texoma, which Texas shares with Oklahoma, indicates the lake’s striped-bass fishery annually generates about $20 million from recreational anglers targeting the fish.
But because almost all of those lakes, unlike Texoma, lacked access to spawning habitat, there was no natural reproduction; the only way to maintain the fisheries in those lakes is to regularly stock them with new crops of fingerlings, creating a putand-take fishery.
Texas began stocking striped bass into reservoirs in the 1970s, using hatchery-produced fish from the landlocked populations in southeastern states. One of the lakes they stocked was Livingston, impounded in 1969 and first stocked with stripers in 1977.
Some of those stripers ended up in the Trinity River downstream from the dam, where they thrived and even manage modest reproduction.
Since 1981, the stripers congregating around the tailrace of Lake Livingston Dam have been the lone source of brood stock used by TPWD to produce striped-bass fingerlings and striped/white hybrid in the agency’s hatcheries. It is the only place in the state where fisheries managers have a reliable concentration of fish and, thanks to cooperation with the Trinity River Authority, access to those fish.
“One hundred percent of the brood fish we use in our hatcheries come from this river,” Todd Engeling, TPWD hatcheries chief, said last week as he helped oversee the annual striped-bass brood-stock collection effort. “We couldn’t do what we do without these fish.”
The annual two-day brood-stock collection is a logistics-intense effort that takes considerable planning and coordination. Timing is everything
The effort is timed to coincide when large numbers of adult female striped bass are a week or two from releasing their eggs.
“We have to hit it at the right time,” said Brian Van Zee, TPWD inland fisheries regional director. “The water flow has to be right, and we’re looking for female fish that are six to 14 days from ovulation. Usually, that’s in early April.”
Fisheries crews collect the fish using electrofishing boats. The vessels are rigged with generators that produce electric current, which flows into the water around the boat via twin booms mounted on the boat’s bow.
The current temporarily stuns fish in a small area around the booms, with the briefly paralyzed fish floating to the surface, where staff uses long-handled nets to scoop the fish, swing them aboard and place them in a water-filled holding vat. It is challenging, physical work in a rough, hard-flowing current that demands skilled boat operation and coordination.
Once several fish are collected, they are taken to the bank and put into large tanks, where males are separated from females. The development stage of a female striper’s eggs is checked using a small tube inserted in the vent that collects eggs for inspection. If the eggs are less than 14 days from ovulation, the fish is weighed, taken to a table where it is given an injection, a fin clip is taken for DNA cataloging and an identifying streamer is clipped to its dorsal fin. The process takes less than a minute after which the fish is placed in a water-filled tank on a trailer.
When those trailers have their quota of fish — males and females — they head directly for one of TPWD’s fish hatcheries. There, staff hand-strip eggs and milt from the fish, putting both in a large beaker, where a turkey feather is used to mix the eggs and milt. The fertilized eggs then will hatch in two to four days.
TPWD looks to annually collect about 100 female stripers as well as a smaller number of adult males from the Livingston tailrace each year, Van Zee said.
Those fish produce 2.5 million to 2.8 million striped-bass fingerlings that will be stocked into the dozen or so Texas reservoirs that TPWD manages as striped-bass fisheries.
The fish, most of them 2 to 5 years old, also provide eggs used in producing 2 million or so striped/ white bass hybrids, which are stocked into more than two dozen Texas lakes, Van Zee said.
Last week’s stripedbass brood-stock collection effort was hugely successful, he said, with crews finding large numbers of adult stripers, some weighing as much as 25 pounds, congregating in the fast water of the tailrace.
The progeny of those fish will be stocked in Texas waters later this spring, just about the time many Texas anglers begin focusing on chasing schools of striped bass and hybrid bass on the more than 40 lakes that owe the existence of those fisheries to what happens in the Lake Livingston tailrace each April.