Edtiorial: Trout Plants

Editorial: The fate of planter trout

Western Outdoor NewsPublished: Nov 07, 2018

Have you ever wondered the fate of hatchery-raised trout that are planted in streams and rivers? Well, our staffers here in California have caught holdover planters that we know were at least a year old, if not more from their re-grown tails and fins, but according to a study in Arizona, most planter trout don’t last more than a week after being planted!

Arizona just completed a 4-year study that began in 2013 to investigate the fate of rainbow trout and Apache trout stocked into several of Arizona’s popular stream trout fisheries.

As part of the project, Arizona Game and Fish biologists conducted nearly 5,000 angler interviews on six different streams — Canyon Creek, East Fork Black River, East Verde River, Silver Creek, Tonto Creek, and West Fork Little Colorado River — during the trout stocking seasons, April to September, of 2013–2016.

From these interviews, biologists estimated the total harvest (number of stocked trout kept by anglers), angler effort (total time spent fishing by anglers), and angler catch rates. The biologists also implanted trout with radio transmitters in order to track their movements and determine how long they survived in the streams.

The first thing they learned was that most planted trout don’t survive past one week of being stocked, although in one stream they studied, 71 percent of radio-tagged trout remained alive after one week.

For the study, Arizona biologists implanted 492 trout with radio transmitters, and after one week in the streams 60 percent of the trout were no longer alive. It was several weeks before the percent of trout remaining from a single stocking was below 20 percent. Consequently, in Arizona, they re-stock streams every 1 to 2 weeks.

An interesting factoid is that the longest surviving trout was a pair of Apache trout that were still alive 123 days after they were stocked, when they were detected on Dec. 4, 2015 in the East Fork of the Black River.

Anglers were not the only ones eating stocked trout. Birds and mammals, such as ospreys, great blue herons, and raccoons, consumed between 6 to 30 percent of radio tagged trout.

This tells us that rather than cut back on planting trout for anglers here in California, as the Department of Fish and Wildlife (DFW) continually wants to do, trout plants in heavily-utilized waters should be increased — especially with the outrageous price of buying a fishing license in this state.

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