Fish sampling requires the use of direct current electricity supplied by the electrofishing gear. There are three main types of equipment used during the Biological Assessment fish collection.

Backpack Shockers

One to three battery-powered backpack shockers are used to electrofish smaller streams. This is accompanied by one to three persons netting the fish and placing them into containers to be identified, counted, and released immediately following the fish sampling.

Barge Shocker

A barge shocker, or "tow boat" is a small vessel that carries a generator, electrical control box, retractable electrodes, and a live well. This device is used in relatively deep or wide wadeable streams which cannot be effectively sampled with backpack shockers. It is not uncommon to use additional backpack shockers to accompany the barge, using them to shock shallower areas or side channels.

Boat Shocker

The boat shocker is only used for the non-wadeable rivers occasionally sampled in the Biological Assessment program. This is a boat, manned by 3-5 people, which contains a generator and electrofishing gear. It is used to sample areas of larger rivers that are too deep and wide to be sampled with any other means.