THREADFINSHAD MANAGEMENTANDCULTURE

Billy Higginbotham*

Threadfin shad is one of the most important Although threadfin shad are introduced to forage in many Texas lakes and increase the food supply for sportfish species, reservoirs. The threadfin’s native range includes sufficient numbers must survive to reproduce. most of the southeastern United States, but it has been successfully introduced as far away as Lakes Suitable for Threadfin Shad California. In Texas, this species has been New or recently renovated lakes (containing no stocked in many smaller lakes as additional populations) are best suited to threadfin forage for sportfish such as largemouth bass, shad introductions. They should be at least 10 catfish and crappie or to aid in correcting acres in size (the larger, the better) with some stunted largemouth bass populations. deep water to decrease losses from winter kill. In lakes smaller than 10 acres, threadfin shad may Advantages and Disadvantages provide an excellent food source and promote The small size of threadfin shad at maturity (2 faster predator growth during the first summer to 5 inches) makes this species a readily avail- following stocking. In addition, annual spring able food source for predators. In addition, the introductions may be feasible to maintain shad high fecundity and early maturation rates if a supplier is readily available. If the lake is fairly (young hatched in the spring often spawn the fol- clear, begin fertilization. Place broken bales of lowing fall) help sustain the shad population hay near the shoreline (late spring to early fall) to from year to year. provide spawning habitat. However, threadfin shad is not successful in all Threadfin shad often are stocked in lakes with lakes. One reason is its sensitivity to extremely established fish populations to control stunted cold water. Small, shallow lakes open to pre- bass or to increase sportfish. Introducing shad is vailing winds cool down during cold weather more difficult in populated lakes because of more rapidly than deeper, larger lakes and may predation and requires higher stocking rates. become too cold for shad survival. Such lakes are not good places for stocking shad. Stocking Rates Threadfins are also less likely to become estab- Depending on the lake’s characteristics, the lished in small lakes (less than 10 acres) with following stocking guidelines for threadfin shad existing fish populations because of heavy feed- are recommended: ing pressure exerted by predatory species. Being a slow swimmer, the threadfin is vulnerable to Lake Characteristics Stocking Rate predation. Since most predators prey mainly by sight, clear lakes are less likely to sustain a shad New or population. Clear lakes can be made more renovated lakes 100/surface acre suitable for shad by fertilization which gives the water a greenish color and produces more food Lakes smaller for all the fish in the lake. than 100 acres* 200/surface acre

*Wildlife and specialist, 1890 Extension Programs Lakes larger at Prairie View, Texas Agricultural Extension Service, The than 100 acres* 100/surface acre Texas A&M University System. *fish populations already present

37.18 When to Stock at the rate of 80 pounds/surface acre, can be Ideally, threadfin shad should be stocked just used. Organic fertilization using fresh cow prior to the spring spawning season (April manure at the rate of 500 pounds/surface acre through June) in lakes with established fish has also been successful. populations (specifically predatory species). This Adult threadfin shad are stocked following helps reduce the effects predation may have on fertilization at the rate of 100/surface acre. If the shad before spawning occurs. If the shad are threadfin shad are available in the lake to be stocked earlier, the chances of survival are better, stocked, broodfish can be collected by shoreline but predation may be increased. Every situation seining at night. Otherwise, broodfish can be is different, but consider these factors when purchased from a commercial fish producer. scheduling the delivery of shad. Spawning usually begins in April or May in In new or renovated lakes, stock shad during Texas and continues through the summer. Six- the fall, winter or spring months and allow them inch layers of hay from bales should be stacked in to spawn once prior to introducing predator shallow water to provide spawning habitat. species. Supplemental feeding of threadfin shad using a floating catfish ration has increased produc- Threadfin Shad Culture in Nursery Ponds tion in some ponds. One successful feeding rate A nursery pond is a useful long-range manage- is 8 pounds of ration/surface acre on a 5-day-a- ment tool for sportfishing lakes. Forage or sport- week basis. fish species can be spawned and/or grown as Overfeeding, overfertilizing or placing exces- needed for supplemental stocking. sive amounts of spawning material in a nursery Nursery ponds should be located adjacent to pond can result in an oxygen depletion and fish the lake and connected by a drainpipe or die-off. An emergency water source should be gate/ditch system. The pond should be from 0.1 available to help prevent possible oxygen to 1.0 acre in size, slope from 2 to 6 feet in depth problems and to maintain water levels during and have a smooth bottom. The gate or drain the summer. should be located at the deep end of the pond and In a well designed nursery pond, stocking is constructed so that all pond water can drain into accomplished by simply opening the drain or the lake by gravity flow. This type of pond is es- gate to flush the shad into the lake. Some pecially suited for threadfin shad production. threadfin shad have been successfully stocked by Well or filtered lake water should be used to fill transferring the egg-laden spawning material the nursery pond and to prevent the introduc- directly to the stocking site. However, losses by tion of undesirable fish species. Threadfin shad predation in populated lakes maybe high. Yields are and detritus feeders, so fertiliza- of 50,000 to 100,000 threadfin shad/surface acre tion in mid-March will help provide an adequate are possible if good culture techniques are used. food supply. Inorganic fertilizers. such as 20-20-5

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Cooperative Extension Work in Agriculture and Home Economics, The Texas A&M University System and the United States Department of Agriculture cooperating. Distributed in furtherance of the Acts of Congress of May 8, 1914, as amended, and June 30, 1914. 5M–6-83 WF