Does it really matter what forage you choose if your predators will eat either one? It matters more than you think! Choosing the right forage fish for your pond is crucial for the health of your fishery and for ensuring that your fishery is growing quality fish and achieving your lake management goals.
Believe it or not, stocking the wrong forage for your unique fishery could be detrimental both to the health of your fishery, and to your wallet! Read on as I break down how to make the most of each fish stocking season and ensure that your pond stays healthy, and your fishing stays fruitful, relaxing, and consistent.

What's the Difference Anyway?

Well, to many the difference appears minimal. Both threadfin and gizzard appear almost identical when younger, but there are a great number of differences between the two including:

  • Spawning Rate
  • Growth Rate
  • Habitat
  • Predators

These differences can make a world of difference in determining which is right for YOUR pond to maximize its productivity. 

Spawning Rate

Threadfin shad spawn early and often, as they tend not to live more than a few years at best. They tend to spawn when water temperatures reach the upper 60s, laying between 2,000 and 20,000 eggs in grassy substrates often close to the shore. Although these fish can grow up to 7 inches, many would be lucky to make it that far, with a great majority getting consumed before they can reach adulthood. Due to this aggressive spawn rate and relatively small size, these fish make perfect forage for balanced fisheries containing smaller largemouth bass, crappie and catfish. In fact, threadfin shad make up a good majority of the average forage base for crappie in most southern ponds.

Gizzard shad, on the other hand, tend to spawn in warmer weather, with female gizzards laying well over a quarter million eggs which hatch within the week, sending thousands of fry into more open water as they feed on zooplankton and phytoplankton in the water column.

Growth Rate

Although threadfin will spawn much earlier in the year, the head start doesn't mean much in the face of the voracious growth of gizzard shad fry. These newcomers will quickly catch up to the size of the threadfin in the pond and in many cases will be seen in some of the same schools with threadfin of similar size. However, despite hanging around the threadfin shad, gizzard shad will continue to grow at a much faster rate. Where most threadfin get consumed before even reaching 5-6 inches, most gizzard shad will develop to 4-7 inches within the first year, quickly outgrowing the mouths of many small predators, making them difficult to control in a pond that contains many stunted bass or crappie.

Threadfin rather than spawning one time will spawn in the spring, summer, and sometimes even the fall, with many young fry also venturing into the open water to consume zooplankton as they grow. These young fry will often grow up to three inches in their first 3-5 months, then slowing to only gain an inch every 3-4 months, often growing to only 5-6 inches at adulthood.

Habitat

The differences between these two species of forage fish are far more extensive than just a difference in size. The two species also have very different behaviors when it comes to their habitat within a lake. The much larger gizzard shad will move from the open water to shallow water when they begin to surpass the smaller threadfin shad. The gizzard shad will move from consuming mostly zooplankton to a diet which begins to consist of more varied types of detritus, worms, bacteria, periphyton, and other organisms that can be found at the bottom of the lake, using their namesake gizzard to help digest many of the varied food types that they turn to as they develop. These fish can still be found schooling in deeper water but may not spend as much time here as threadfin shad might.

Speaking of which, threadfin shad can be found almost exclusively in deeper open water, often schooling in groups large enough to be seen disturbing the surface of the water. The smaller shad use this as a defense tactic to disorient or dissuade larger predators from attacking the school. Many pond owners will notice these schools in the late summer if fish stocking is done in the spring.

Predators

These two fish will begin their lives facing some of the same predators, which are in short, just about all of them. As a soft forage (one that lacks any spines on their dorsal or anal fins), juvenile shad will be extremely attractive forage items for many size classes of bass as well as crappie, catfish, and other forage fish present in a fishery. Due to their rapid reproduction, threadfin shad function as an excellent persistent forage item for smaller bass that can be stocked yearly to supplement established forage even if a lake does not maintain warm enough waters to support threadfin shad year-round (threadfin shad will die when water temperatures dip below mid 40s).

Gizzard shad on the other hand is not the catch-all forage item that threadfin may be. In many cases, a fishery may not be well suited for these fish. As gizzard shad quickly outgrow the mouths of many intermediate sized bass and other predator fish, one must ensure that their fishery contains enough large predators to control the population. Generally, it is recommended that a lake contain a well-established population of bass over 18 inches before gizzard shad are stocked to ensure that the shad population does not stunt the rest of the lake, as there have been instances of gizzard shad populations becoming dense enough to suppress reproduction of other fish. 

So, Which is Right for My Pond?

The species of shad that will be best for your fishery comes down to the matter of which fish are already in your pond as well as your goals for the fishery. In some cases, the best strategy might be to stock both species to supply a diverse forage base for your predators, while other ponds may benefit from a stocking plan that includes exclusively threadfin shad. To determine the best baitfish for your pond, you must first determine why you are stocking fish to begin with.

Are you stocking in: 

  • An established trophy fishery with large bass
  • A balanced fishery with quality bass, but not many large bass
  • A stunted bass fishery, or crappie pond
Determining which of these describes your fishery will help you choose the best strategy for stocking threadfin shad vs. gizzard shad in your pond.

An established trophy fishery with large bass

In an established trophy fishery, it may be beneficial to stock either gizzard shad or both species of shad, especially since the significant population of largemouth bass greater than 16-18 inches will find the new large forage to be an excellent source of dense nutrition. These bass will keep the gizzard shad population in check, allowing other forage species such as bluegill to grow without intense pressure from predators. 

A balanced fishery with quality bass, but not many large bass

In a fishery that contains a good number of larger bass over 16 inches, but not many over 18, a land owner will have to determine whether or not their pond could support gizzard shad, and in some cases may choose to exclusively stock threadfin shad to avoid the risk of a gizzard shad population growing out of control, which could stunt the growth of bluegill and other forage species. If a large pond contains a significant number of bass over 16 inches, stocking gizzard shad may be an option. 

A stunted bass fishery, or crappie pond

Gizzard shad should not be stocked in a pond that does not contain large predator fish or bass over 16 inches. Threadfin shad may still be stocked in these conditions to provide new forage for predators or take pressure off bluegill, but gizzard shad should be avoided until the present bass have grown large enough to consume adult gizzard shad. 

Threadfin Shad vs. Gizzard Shad

Which to stock in your pond comes down to your lake management goals as well as the size of established bass in your pond. In many cases, stocking threadfin shad can be a good idea to add some diversity to your forage base and provide some relief for bluegill, the backbone of your forage population, allowing them to spawn without heavy predation until the threadfin either die off due to low water temperature, or are consumed entirely.

Gizzard shad on the other hand should be reserved for only ponds that contain large bass, generally over 16-18 inches, which will be able to consume the adult gizzard shad. In these cases, gizzard shad can be a great forage option for the cost, providing a nutrient-dense forage option for the bass in your pond.

We can help!

Ultimately, if you're unsure of which fish to stock in your pond, give us a call! Our expert biologists are always available to help you achieve your dream fishery through proper stocking and management. With over 25 years in the industry, we understand that managing a lake can be a daunting task, and that's why we're happy to help so you can enjoy your lake without the hassle.

Call us today to speak with a specialist and develop your individualized stocking and management plan, we look forward to working with you! 

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