It's a particularly common problem in Houston-area bayous and streams feeding the bay systems, Denton said. With the region's natural waterways ditched and channelized to maximize their drainage efficiency, they move lots of water and debris very quickly. Dickinson, Bray's and Buffalo bayous are particularly susceptible, Denton said. Dead-end canals, common in shoreline developments on bays, also account for a considerable number of fish kills caused by oxygen depletion, Denton and Buzan said. The canals, cut off from normal circulation that can pump oxygen into water, often prove deathtraps to fish.
Pollution also accounts for a considerable number of fish kills.
In particular, Buzan said, the maze of oil and gas pipelines in the state poses a problem. In many cases, such incidents occur in isolated areas and in small streams - places hard to get to and seldom seen. And even when kills are reported, it's often tough to finger a cause or make a comprehensive body count. When the Kills and Spills team does collect enough evidence at the site of a fish kill to place the responsibility on some human activity, it can result in the state being repaid for the damage done to the public fishery. Texas law allows TPWD to seek civil restitution for the value of wildlife resources killed illegally.