74313 REL 60

1986-050-00 EXP EVALUATE STURGEON POPULATIONS LOWER COLUMBIA

10/1/2019

9/30/2020

157. Collect/Generate/Validate Field and Lab Data

Work Element Usage Report

D: 157 - White sturgeon recreational fishery monitoring for Bonneville, The Dalles, and John Day reservoirs

Monitor sport fishery effort and catch in Bonneville, The Dalles and John Day reservoirs (Zone 6).

Sport harvest is monitored and estimated by using a modified roving creel survey approach. Sampling is conducted in Bonneville and The Dalles reservoirs, and that portion of John Day Reservoir from McNary Dam downstream to Arlington, Oregon, by one creel sampler hired by ODFW and three creel samplers hired by WDFW. A WDFW biologist coordinates sampling activities.

Creel surveys are scheduled throughout the week in a manner that assures sufficient observations are made for each day of the week over the course of the month. We aim to have at least three days of observations during the Monday through Friday period, and at least one day (though often both days) on the weekends. Creel samplers usually work 4 ten-hour days.

Surveys are limited to legal angling hours for white sturgeon (one hour before sunrise to one hour after sunset) and the duration of the recreational white sturgeon retention season specific to each reservoir and year. Systematic counts are used to collect data on angling effort and anglers are interviewed to collect data on catch composition, catch per time, and to sample the catch for mark-recovery and biological data.

Angling effort (in hours) is estimated by counting anglers within representative index areas for each reservoir and expanding those counts to the entire reservoir by using data on index to non-index angler distribution patterns collected during aerial counts made during surveys conducted from 1987-1991. Counts are made of all bank anglers and sport-fishing boats within each index area. The average number of anglers per boat is determined from angler interviews. Angling pressure within index areas is counted once a day between 1000 and 1300 hrs and the count is expanded for angling effort occurring during the rest of the day using previously collected data on the hourly distribution of angling pressure through the day. Hourly distribution patterns were established from 1987 to 1991 when counts were made every other hour from one hour before sunrise to one hour after sunset.

Anglers are interviewed to collect data on catch composition and minutes expended fishing to calculate catch per hour. Boat anglers are interviewed once they return to boat ramps. Bank anglers are interviewed at the locations they are actively fishing. Harvest estimates are calculated as the product of observed catch per hour within a reservoir subsection and total estimated effort for that subsection. Harvest estimates are made for each angling method (bank/boat), reservoir subsection, and weekend/weekday type to account for differential catch and sampling rates. Harvest and angling effort estimates are derived weekly.

The species composition of each angler’s catch is recorded and all white sturgeon are measured for length. Each sturgeon is scanned for PIT tags using an electronic detector.

We try to sample at least 15% of the season’s sport catch, but we do not have a set number of interviews to achieve each day, week, or month. All anglers, regardless of species being fished for, comprise our target population, since we can’t always identify sturgeon-specific anglers during the index effort counts. Our capacity to interview anglers is limited to the number of individuals that our four samplers can contact during the day. We try to sample as many anglers as possible throughout the reservoir as long as we distribute the sampling among both bank and boat anglers. On some days there may be few if anyone fishing while on other days there will be hundreds of anglers.

Anglers have shown limited interest in fishing for sturgeon during periods of the year when retention is prohibited. We typically observe a 90% or greater drop in angling effort for sturgeon once retention closes. Retention season length can vary substantially among years and reservoirs. In 2012 the retention season lasted into November in The Dalles Reservoir. There is an exception to this pattern. Some individuals, along with guides, are keenly interested in catch-and-release fishing for over-legal size sturgeon that tend to concentrate immediately downstream of the dams during late-spring and summer months. They participate in this activity whether or not retention is allowed. We have implemented spawning sanctuaries, where no sturgeon fishing is allowed, to protect spawners from the stress of being handled in this fishery. The fishery tends to locate immediately downstream of the sanctuaries. We sample anglers participating in this fishery if the reservoir is still open to retention.

Angling effort, pressure, and distribution; catch per hour for each angling method (bank/boat), reservoir subsection, and weekend/weekday type; species composition of each angler’s catch and white sturgeon lengths; PIT tag data for white sturgeon.

We actively sample the periods of the year open to sturgeon retention. Retention season length can vary rather dramatically among reservoirs and years and is influenced by the number of sturgeon available for harvest (i.e. pool-specific guidelines). Our longest season in recent history was in 2012. The Dalles Reservoir remained open to harvest from January 1 through November 3. A more typical season runs from January to April/May, sometimes into June or July.

$512,000

36.99%

10/01/2019

09/30/2020

09/30/2020

Concluded

n/a

n/a

Recurring