It was a tough year for bass fishing at Grenada Lake. After back-to-back drought years from 2005-07, the lake caught some water in 2008, and resembled more typical years. Lots of water but, unfortunately, no bass.

The problem is recruitment, which is a scientific term that means the production and survival of bass to catchable size.

Spawning is only a start

You can't produce more bass without a good spawn, but bass spawning is rarely, if ever, an issue in Mississippi reservoirs. Largemouth bass are pretty flexible - any hard substrate in 2 to 8 feet of water and isolated from currents
and heavy wave action will usually suffice.

Shortly after hatching, the bass need food. Microscopic zooplankton provide nutrition for the first two to four weeks as the bass gain size. At around 1 inch long, they start feeding on insect larvae, small crayfish and other invertebrates living on the bottom or on above-bottom substrates like brush, aquatic plants or flooded terrestrial vegetation.

The young bass can keep eating invertebrates, but by the time they reach 2 inches, they need to switch to a fish diet for rapid growth. Shad fit that need, but provide food for the young bass only briefly because the shad grow quickly to a size too large for most young bass to consume. Young minnows and sunfish are important foods after the shad become too large.

The problem with Grenada

The poor bass fishing at Grenada, according to Mississippi Department of Wildlife, Fisheries and Parks biologist Keith Meals, who oversees fisheries management in Grenada, is the result of several years of low and turbid water. Meals has observed poor production of sunfish and minnows under low, turbid water conditions in previous years.

Without a good forage supply, the young bass grow slowly. Growth is survival for young fish - the faster you get bigger, the fewer are the fish that can eat you. Slow growth, therefore, means poor survival of the young bass. And those that escape predation have to survive their first winter.

Winter is tough on young bass because food is limited, and they often have to live off the energy stored in their bodies. Larger fingerling bass have more energy reserves that can be used to make it through the winter.

A weak year-class of bass is not uncommon in widely fluctuating flood-control reservoirs. Meals' creel surveys indicate low bass harvest in Grenada. With low mortality, bass remain in the fishery for six to eight years, so an occasional weak year-class of bass is not a problem.

But three successive weak year-classes - that's a problem. And that's what bass anglers witnessed this year.

Wait 'til next year

Meals has been managing fisheries in Mississippi long enough to know that it's not wise to predict the fishing, but he is highly optimistic about a dramatic turnaround in the bass fishing at Grenada.

Although Grenada didn't get to full pool in 2008, the lake filled enough to flood into the abundant smartweed that colonized the drawdown zone during the prolonged drought. The flooded vegetation supports a rich food supply for a variety of fishes, including bass, and provides refuge from predators. With weak 2005, 2006 and 2007 bass year-classes, predation will be low, and competition for forage will be minimal.

Everything we know about factors affecting largemouth bass recruitment indicates the 2008 year-class should be strong and rapidly growing.

No more three-peats

Will poor year-classes of bass become the norm in Grenada? They may if drought conditions resume, but there are management options to minimize weak bass year-classes, or at least the effect of weak year-classes.

One solution is a high minimum-length limit or a slot limit. Protecting a wide size range of fish keeps quality bass in the catchable population longer and smooths over the dips in abundance that result from weak year-classes. It may be desirable to raise the minimum length limit or to expand the protected slot limit under conditions of successive weak year-classes.

However, Meals points out that creel surveys indicate bass harvest is already low, so the effectiveness of harvest restrictions is questionable.

Providing good habitat for the young bass and their forage is the best solution. Extensive efforts are under way to establish aquatic vegetation in reservoirs throughout the southern United States. Unfortunately, the extreme annual drawdown and turbid water in Grenada prevents establishing aquatic vegetation with conventional procedures. Grenada was built for flood control, and floods are serious business in the Mississippi Delta. I do not see changes in water-level management in the near future.

Meals suggested that an earlier drawdown would allow establishment of terrestrial vegetation that, when flooded next year, would provide good habitat for young bass. This idea makes good sense biologically, but may meet some resistance from anglers and waterfront property owners.

Grenada will continue to pose management challenges, and poor years will follow good years. But the converse is also true - good years will follow poor years. Sustaining quality bass fishing in Grenada will depend on the will of the anglers.