The Importance of Forage in Bass Fishing

By

Steve Magnelia

TPWD Fisheries Biologist

3/31/2006

            Watching coverage of the recent BASS Elite Series event at Lake Amistad I took note of a comment by Kevin VanDam on modifying his spinnerbait to mimic the dominant forage.  VanDam said he started out with a  shad imitating spinnerbait and couldn’t get a bite on it.  After switching to a brim/tilapia imitation and fishing the same water he caught over 100 bass in practice and ended up with a top ten finish in the tournament.  This was a simple modification, changing the skirt to a greenish/brown color and coloring the head of the bait red with a marker.  I’d never really thought of a spinnerbait as a brim imitation, and had always used a crankbait or plastic bait when wanting a brim imitator.  While a fluke or wacky worm would have probably caught some fish in this situation, a spinnerbait allowed VanDam to cover water extremely efficiently and still generate plenty of strikes in the clear water.  Because of the extreme water clarity at Amistad, a crankbait may not have fooled the fish as well.  Many scientific studies have been done on the forage of black bass.  The common denominator in most studies is that forage often changes seasonally, with bass eating what is most abundant at the time.

Brim are often the dominant prey fish species for largemouth bass in Central Texas reservoirs and are the dominant forage fish in reservoirs which have abundant aquatic vegetation.  Anytime bass inhabit shallow water these small sunfish species will be a main prey item.  The three dominant sunfish species in Central Texas’ large reservoirs are redbreast sunfish, bluegill and redear sunfish.  Redbreast sunfish dominate in reservoirs without vegetation, while bluegill dominate in reservoirs with aquatic vegetation.  Redear sunfish are present in lower densities in both situations, often inhabiting deeper water than the bluegill and the redbreast sunfish.  These species are prolific spawners, with peak spawning in late-March and April, and often have multiple spawns from the late-spring and into summer.  Multiple spawns creates many cohorts of different sized prey for bass to feed on.  During the spawn and post-spawn bass will be up in the shallows and their main food item, small sunfish, will be right there with them.  In reservoirs where bass stay shallow all year sunfish will remain the dominant forage.

Gizzard and threadfin shad are also important food items for bass.  However, these are an open water species, and other to spawn, spend much of their lives in open water.  In reservoirs with good open water structure and little vegetation shad will often be a major food item, and/or will be seasonally abundant.  Shad are also prolific spawners and usually spawn in Central Texas starting in mid-to-late March.  Adult shad in March are too large for most bass to eat, so if bass are feeding on shad at that time they are going to be small.  Downsizing your bait or spinnerbait blades might help trigger strikes in that situation.  In early (May – June) when bass are moving to offshore structure or deep weedlines shad may become a primary food item.  Shad grow very quickly and will be 1-1.5 inches by that time.

Crayfish are also important food item, especially early in the year, when sunfish and shad numbers are low.  If you’ve ever looked at a crayfish from Lake Austin you can see why red and orange baits have been so successful in Texas early in the year.  Crayfish in Central Texas really are red and green, often with orange dots on the pinchers this time of year.  I’ve also seen them this color in November and have often wondered if they remain this color all the time in Texas waters or change color throughout the year.  Interestingly, a friend of mine from Florida, gave me back a red rattletrap I’d given him years ago saying he couldn’t catch anything on it in Florida waters.  He claimed chrome with a blue back was the only color rattletrap they had success on in Florida.           

Adjusting bait color and size is a key component to success in bass fishing.  Very successful anglers, like Kevin VanDam, always seem to be making adjustments to match the conditions.  Next time you’re on the water and aren’t catching them, think about the conditions and be sure to include the main forage the bass are feeding on in your decision making.

Figure 1. Percentage of largemouth bass forage collected during fall electrofishing surveys from Fayette County Reservoir, Texas, 1983-2001.