Understanding Seasonal bait migration patterns

[Geraldlim]

How do the shad schools migrate within the lake across the seasons?
What are the governing factors? Water temp?
When I started fishing in December they were up in the shallows near shore and on the surface in the main lake. Then they disappeared from the shoreline and I was metering them over deep structue. Now I don't hardly see them at all, which means I am not looking at the right places.

Please help this novice understand.
Thanks in advance!
Gerald

[Stormcrow]

Shad migration patterns are difficult to predict. Water temperature is a factor, simply because it helps to govern the availability of the phyto and zoo plankton that make up their diet. So, just as stripers follow the shad....shad follow the blooms of plankton, which react to changes in water temperature, thermal layers and oxygen availability. As a general rule, cooler water can hold more dissolved oxygen, hence, support larger blooms of plankton. But because water temperature can change by depth as well as simply where you are on the lake, this is harder to pinpoint.

Hope this helps.

Jason

[smokehound]

When the water is cold, threadfin shad have massive die-offs, because they are a warm-water fish, and cannot tolerate cool water for long. 40 degree water is generally lethal to threadfins.

Once the water goes over 60 degrees, the threadfin exit their holding spots, and spawn.

In winter, the only places you will find threadfins, are areas that are warm enough to allow them to survive, though because of the massive die-offs, you wont find very many.

You should be able to find them much deeper during winter.

[DodgersFan]

im aware that the shad go deep in winter but my question is if they like warm water why do they hold down in the cold deep depths????

[Fishbreath]

Shad dislike shifts in water temperature even more that cold water. A sudden shift of even just a few degrees can trigger a massive die-off. They hold in deeper water because the water temperature is more stable. If you are talking about winter, then shad really don't feed that much in the winter. It is all about survival. Here is an interesting article I came across some years ago and saved:


~ ~
Bass Biology
Shad – Weathering Winter
By Wayne Gustaveson

November/December 1997

Most bass waters in the arid West are manmade impoundments without a natural population of predator and prey fish. The fisheries consist of intentionally introduced sport fish, and forage fish mixed with other fish that were present when the pond was formed or added later by subsequent introductions. In many cases the naturally occurring minnows cannot supply enough forage to allow the bass population to expand in numbers to the satisfaction of the anglers that use that fishery. More times than not another forage fish is needed. In the West, the fish of choice is the threadfin shad.

The name comes from an elongated fin ray on the trailing end of the dorsal fin that extends almost to the caudal fin. It looks just like a thread hanging from the dorsal fin. The slender silver fish sport a neat, black body spot just behind the gill plate. The fins have a yellow cast in the adults and the backs are an iridescent blue-green. Probably the most important characteristic is that all game fish seem to prefer eating shad to the exclusion of just about anything else except maybe the crayfish.

Shad are prized forage because they remain the ideal eating size all of their life and they have no spines or sharp edges to discourage predators. This delicate body that provides such fine food to our game fish is really sensitive to environmental stresses. Shad caught to be used for bait are very hard to keep alive. They require a high oxygen environment and withstand very little handling. The most critical need of threadfin shad is stable temperature. They cannot stand drastic temperature changes.

This tiny gladiator, which may be the greatest forage fish every made, would probably be wider spread if it could withstand cooler temperatures. The rule is that a body of water that freezes over in the winter is too cold for threadfin shad survival. Water under the ice generally maintains a constant 39 F. The lowest temperature threadfin can survive is 40 F and then only for a short time. If the water were colder than 40 F for more than 2 days all threadfin shad would die. In situations where ice-over occurs the larger gizzard shad can survive but the size of this larger shad and its rapid growth make them a poor second choice to threadfin in most instances where bass fisheries are concerned.

Threadfin start to shiver when temperatures fall to 57 F. Shad behavior between 57 and 40 F is important for winter angling. Generally, water cools slowly falling a degree per day. In these conditions shad seek out the warmest water available. If warm springs or warm inflows are available shad will flock to those areas and bass and other predators will be in hot pursuit. Without thermal sanctuaries shad dive to deep water where water temperature is constant. Shad do not feed or move much when temperatures is below 50 F since they are totally driven by temperature and staying alive. They can acclimate to cold water but they don’t have to like it. Shad are schooling fish and cold temperatures make them school more tightly and in larger numbers. It could be that they crowd together to get warm.

Storms with high winds are a shad’s worst nightmare. An arctic front with high winds may cool a shallow body of water by 5 degrees or more. This drastic change in temperature can lead to loss of shad to thermal stress or winter kill. Rapid temperature change is lethal in the 40-55 F zone. Death comes just as certain to shad in the spring when a warm wind can warm the water too quickly for shad acclimated to cold water. That is why shad go deep to find stable temperature that cannot be as readily influenced by surface winds.

These catastrophic events lead to shad behavior that is distinctive and one that can be duplicated by a knowledgeable angler. Shad in thermal stress exhibit rapid bursts of swimming followed by a lifeless fall toward the bottom. The fish can right itself and then quiver and swim again before falling once more and finally ending up on the bottom. The action of a lightweight jigging spoon closely resembles the final demise of thermally shocked shad. Bass that have witnessed winter shad behavior may be favorably influenced by a silver spoon fluttering near or below a school of healthy shad. Winter bass may be suckers for a spoon that rests on the bottom and then flutters up 6 to12 inches every once in a while.

Game fish in most waters containing shad are so in tune with shad movement and behavior that anglers must know as much as possible about shad and where shad are at all times to keep up with the fish. Time invested in studying shad movements and behavior will probably be rewarded with a better understanding of game fish vulnerability when it comes time to put one in the live well

[Surfnsnowboard3]

Krocodiles baby

[diamondbear]

THANKS for the insight on the shad FishBreath , real interesting article .

[twcthfsh]

Does anyone know how many different types of shad are in DVL? I've seen at least two different types.

[ddoskocil]

I've seen 1", 2-3", and 4-5" shad. Don't know if they are the same sub-species or not.

[diamondbear]

Ive seen the Silversides , long thinner baitfish in DVL , but not sure on different shad type .