Under the gentle glow of a gentle late-afternoon sun, Richard Harris guided his oyster scow away from the Saugatuck Center marina. As he turned the vessel to face the mouth of the Saugatuck River, it skimmed through a smattering of burnt-orange leaves. He would soon encounter more foliage.

But what Harris set out to find on his voyage resided below the surface: benthic, or bottom-dwelling, fish in the Saugatuck River. Although shrouded from view, these underwater inhabitants illuminate a host of environmental concerns facing the town.

"Everybody talks about us being green -- we got rid of our plastic bags we're doing this, we're doing that," Harris said. "It's like a tree, the top is a little green, but if you go down the trunk into the ground. It's the same old brown color."

Harris frequently notices that "old brown color" as the director of Harbor Watch/River Watch, a water testing and monitoring program run by the Westport nonprofit Earthplace that operates in the Saugatuck River, Norwalk Harbor and other local waterways.

He points, in particular, to the practice of cutting waterfront lawns right up to the river or stream's edge, which eliminates natural growth such as riparian plants that absorb water runoff and reduce erosion.

Illegal dumping of leaves into waterways also has an adverse environmental impact. In a statement released last week, Mozian said leaves that were improperly disposed could clog streams and cause flooding problems for upstream residents. Decomposing leaves, she added, could provoke nutrient overloading in streams, leading to lower dissolved oxygen levels, and the death of dependent aquatic organisms.

Harris added that leafy buildup on riverbeds is uninviting for bottom-dwelling fish.

"It fouls the bottom, so the fish that lay eggs such as flounder and other bottom-dwellers can't use the bottom to raise their young and use it as a nursery," he said. "Basically once the bottom turns into that kind of condition for them, it's kind of hands-off for them."

On the research vessel, which is named Annie, Harris was joined on the southbound trip to the mouth of the Saugatuck River by Earthplace Associate Director Pete Fraboni, Mozian and state Rep. Jonathan Steinberg.

As a Representative Town Meeting member, Steinberg served on several committees that focused on environmental issues such as wastewater management. In his current position, he participates in talks with Connecticut and New York state legislators focused on Long Island Sound conservation initiatives.

"All the people who want those beautiful green lawns, they're using excessive amounts of fertilizer, which the ground cannot absorb," he said. "So, all that extra nitrogen is running off into the rivers and streams."

To determine the current condition of the bottom-dwelling fish population, Harris and Fraboni used a beam-trawler attached to the boat that sleds along the riverbed and collects underwater inhabitants in a net.

After bringing in the trawler following a 300-meter run along the river bottom, Fraboni sorted its haul in a grated dry well on the starboard side of the Annie.

He then transferred the contents to an adjacent wet well. A few black-fingered mud crabs, sand shrimp and mud snails drifted in the water. But no fish populated the basin.

The absence of bottom-dwelling fish from this trawl correlates to their general absence in the Saugatuck Harbor this year, Harris says. Annie's trawls in the harbor this year have yielded an average of less than one benthic fish. Twenty years ago, an average trawl produced between 10 and 15 fish. The number of fish species collected from the harbor during each trawl has also plummeted from about 15 to two during the last 20 years.

The decline in benthic fish numbers affects many other species, Harris noted.

"They are the basis of the food chain," he said. "Your bigger fish and everything else above depends on them."

Fraboni would sift through a similar compilation of marine organisms after the second trawl. He also picked a soggy, blackened tangle of leaves out of the trawler's net.

A third trawl in the mouth of the river finally plucked a fish from the water. Translucent and measuring about an inch long, the fish's species was ambiguous because of its juvenile age. It could have been a porgy, but it was definitely not a bottom-dweller.

"Their body form is compressed," Fraboni said of the benthics. "Now if you're a fish that wants to live in the mid-water, you want to have a torpedo-shaped body like this one, so you can move through the water very efficiently."

Harris would soon turn around the Annie to return to the Saugatuck Center marina, again without any bottom-dwellers to record for the trip. In comparison, the Annie's average trawls this year in the more commercialized Norwalk Harbor have yielded close to two fish on average.

"Next time, Dick, we'll catch some big fish," Steinberg said with a wry smile to Harris, as he stepped off the vessel a few minutes later at the dock.

Harris lingered on the boat a few minutes longer, gazing at the leaf-strewn river. He plans to submit a report on this year's trawls to town and state officials. But a key question remains.

"What I still don't understand is why a harbor this good, and has these attributes of good flushing and has very little industry, is being hit so hard," he said. "By all rights, this harbor should be up on its heels. It doesn't make sense."