Biologist Zeb Hogan holds the tail of a Mekong giant catfish captured and released on November 13, 2007, in the Tonle Sap River in Cambodia.

At the time of the catch, Hogan was monitoring the start of the monthlong bag net fishery, which uses large baglike nets tethered to shore. Some three dozen species are harvested—the occasional giant catfish is generally caught by accident.

One other fishery for the Mekong giant catfish exists in the Golden Triangle region of northern Thailand. (Read about a grizzly bear-size catfish caught in Thailand.)

The giant catfish were once plentiful throughout Southeast Asia's Mekong River system, but the species has declined dramatically in recent years.

• More Photos in the News
• Today's Top 15 Most Popular Stories
• Free Email Newsletter: "Focus on Photography"