Angler Success

Anglers caught more fish after hatchery trout stocking was discontinued.

No matter how you break it down, anglers saw an increase in wild trout catch in the four years after hatchery trout stocking was discontinued.   Success increased from an average of 0.3 wild trout per angler hour in 2010 to 1.2 wild trout per angler hour in 2013.    An average trip of two anglers fishing for five hours netted 2.9 wild trout; in 2013 that figure had increased to 10.6 wild trout.  Note that the sampling periods were slightly different each year, with a common period of May – June through all four years.   Even when controlling for sampling period variation, anglers still caught significantly more fish in the latter years of the study.

Anglers caught more small fish.

The increase in overall catch rates was buoyed by a dramatic increase in catch of trout in the 150-250mm (5.9″-9.8″) class.  In the last year of the project, 2013, anglers started seeing these fish maturing into larger 250-350mm (9.8″ – 13.8″) class trout.

Anglers caught large fish too.

Though more small fish were present in the catch, overall numbers of large fish caught remained relatively constant through the four year study window.  The study record was set and reset several times in 2013, with the largest fish of the study coming in at 495mm (19.48″) fork length.   Additionally, during sampling for the radio telemetry study in late 2012, anglers captured several trout in the 20″ range, including one massive 525mm specimen (525mm, 20.7″).

Fish were bigger early, more plentiful late.

Wild rainbow trout caught in the summer months were, on average, smaller than those caught in the spring. Cutthroat showed a similar pattern with less seasonal variation.   Anglers found greater numbers of wild trout available in May and June.

There are no hotspots.

This section of the McKenzie is subject to significant seasonal water level variation.   Winter floods also reshaped the channel significantly every year of the study.   We recorded the location of each and every fish caught in the study.   Sorry to say, the locations which held fish in 2013 aren’t sure bets for this year, or next.

Catch Per Trip

Anglers experienced more success in later years of the study, as detailed in the headline graphic at the top of the page and in the following charts.

Catch Per Angler Hour

Catch Per Angler Hour, or Catch Per Unit Effort (CPUE), is a common expression of angler success used by fisheries biologists.  Of note is the average CPUE for hatchery trout prior to the study was at best 0.5 fish per angler hour as reported in the 1983 McKenzie Creel Survey.

Catch Composition

Proportions of wild rainbow to wild cutthroat trout varied from year to year as shown below.  Hatchery fish were still a significant portion of the catch.  High water in the final three years of the study may have contributed to wash-downs from upper river stocking.