Depending on location, they generally feature two particular types of bay bottom habitat associated with shorelines and flats. One is a bottom of sand and scattered shell. Such is common to shorelines in the northern half of Aransas Bay and much of Mesquite and San Antonio Bays.

The other is a mixed bottom of sand and grass beds, which are common to the shorelines of southern Aransas Bay and much of Corpus Christi Bay.

Over either type of bottom, the three zones are delineated according to depth and contour. The most important of these is the "break zone" or "drop zone."

This is a transition zone characterized by noticeable depth change over a relatively narrow band of bay bottom. This is where trout spend a lot of time in the spring, particularly from mid-morning to late afternoon on mild, sunny days. The typical depth variation is between 2-1/2 feet on the inside edge to 4 feet on the deeper edge. The depth change can be gradual over a 20- to 30-yard swath along a shoreline or a steep and abrupt drop of several feet along the edge of a channel.

The former is exemplified by the outside beach of Traylor Island in Aransas Bay. Along this shoreline of mixed sand and grass, the bottom slopes gently from the shore to about the 2-foot range where the slope steepens to reach 3 to 4 feet of water over a 20- to 30-yard band.

In contrast, a steep break zone is exemplified by Morris Cummings Cut in Redfish Bay. The channel cuts alongside shallow flats, creating edges where depths can drop steeply from 2 to 6 feet or more.

Whether the drop zone is gentle or steep, it is bordered by a shallow zone.

Along a shoreline, the shallow zone is the band of water between the shore and the edge of the break. This zone is often referred to as "tailing" or "sight-casting" water. It is usually the first zone to target at first light on warm spring days, especially during high tide periods. Trout can also linger late in the shallow zone on overcast days.

On the outside edge of the break is the deep zone where the water depth increases from approximately 4 feet to deeper than the angler can wade. This is usually the zone of least importance in the spring, except during unseasonably cold fronts of early spring when dropping water temperatures drive fish into deeper and warmer water.

However, the deep zone becomes increasingly important to wade anglers in the heat of the summer when the depths will be cooler and more comfortable for trout than the shallows.

Watkins' normal practice at the start of a fishing day is to deploy his anglers knee-deep, waist-deep and chest-deep to cover all three zones until the fishing action indicates the most productive depth. He also watches the schools of baitfish, which often travel a particular zone with gamefish trailing underneath.

Since light, temperature and tide conditions during the day often affect the comfort zone for trout, Watkins may start out wading shallow at dawn, shifting to waist-deep from mid-morning to late afternoon and back to the shallow zone at dusk.

As Watkins expounded on the wade-fishing zones, I recalled observing a spring gill net survey conducted in the Upper Laguna Madre by fisheries biologists of the Texas Parks and Wildlife Department. The biologists had strung their 600-foot nets perpendicular to the east shore of the lagoon. The shoreward ends of the nets were anchored at the water's edge, while the offshore ends reached straight to water as much as 6 feet deep. The character of the shoreline featured a shallow swath of white sand bottom - about 20 to 30 yards bordering a distinct and sharp break to grass beds of 2 to 3 feet deep.

When the biologists checked their nets, they found good numbers of drum and redfish and fair numbers of trout. But there was something noticeable about the distribution of fish in the nets.

The drum and redfish were scattered haphazard along the entire lengths of the nets. The vast majority of the trout, however, were within 10 yards of that break line. The remembrance suggested there was happenstance about Watkins' wading tactics. It's a calculated game plan suited to a fishing guide who is the son of a high school coach.

As far as the Snowdens were concerned, they had locked on a magical date with a magician for a guide. They suggested getting together the same time next year.

"Yeah, we can try for a threepeat," the sports-minded guide said.