Contract Title:
2007-149-00 EXP NONNATIVE FISH SUPPRESSION
Contract Start Date:
5/1/2014
Contract End Date:
4/30/2015
Title:
C: 190 - Mechanically Suppress Northern Pike in Box Canyon Reservoir, Pend Oreille River
Description:
We propose to implement the 3rd year of a 3-year plan to mechanically suppress northern pike (NP) in Box Canyon Reservoir (BCR) on the Pend Oreille River. The project will use 30 gill nets deployed from an 18’ (5.5 m) skiff and a 24’ (7.3 m) Almar landing craft work boat outfitted with hydraulic drum roller. Nets used in this project measure 150’ X 6’ (45.7 X 1.8 m) with 5 equal panels of 1”, 1.25”, 1.5”, 1.75” and 2” (2.5, 3.2, 3.8, 4.4, 5.1 cm) meshes. These nets were developed by KNRD and WDFW in 2010 in consultation with biologists from MN, WI, and Ontario, Canada that have conducted standardized NP surveys for decades. The nets are approximately 45% more efficient at catching NP than WDFW standardized warmwater fish sampling nets and reduce bi-catch.
In 2012-2013, mechanical suppression with 2,246 overnight gill net sets resulted in the removal of 12,260 NP from BCR. Based on 2013 Spring Pike Index Netting (SPIN) results, the adult population in the core area (southern half) was reduced by 91% from the 2011 baseline of 13.2 NP/net to 1.2 NP/net night.
The 2014 suppression effort will commence at ice-out of sloughs in March and continue in two phases through the spring freshet until reservoir elevation declines below 2032 ft. and abundant macrophyte growth limits access and effectiveness of the gear (June). Two complete passes through all known spawning locations (30-35) will be completed in Phase I (March-early May). A minimum of 2 nets will be set at each location for a minimum of two nights to assess variability and depletion level, although more effort will be focused on larger aggregations of NP in known core areas. Data has shown that NP tend to home, congregate, and remain at spawning locations through much of the netting season. If SPIN survey data (collected early May) indicate target abundances have been met, then suppression netting will cease for the year. Phase II mechanical suppression (May-June) will proceed if >1.7 NP/net night in southern ½ of BCR or >0.5 NP/net night in northern ½ of BCR are captured in SPIN survey. Phase II netting will target all slough and backwater locations throughout BCR (n=60) with one 3-man crew for minimum two days and continue until CPUE for that location falls 87% or to <2 NP/net night).
A subset of hauls will be selected weekly for biological data collection in collaboration with WDFW. Data collection will include total length (mm), weight (g), sex, maturity, fecundity, and scales and cleithra (for aging). Data will be recorded on Rite-N-Rain paper in pencil and later entered, QA/QC performed, analyzed, interpreted and reported to funding agencies. Scale/cleithra will be delivered to WDFW aging lab in Olympia, WA for analysis.
We expect to remove 2,000-4,000 NP during this years suppression effort, which must be disposed of. Preliminary data collected during 2011 indicated increasingly elevated levels of mercury in small (<20”), medium (20”-30”), and large (<30”) NP. Based on samples collected in 2011 and 2012, elevated mercury content warranted the WA State Department of Health to issue a consumption advisory for NP in the Pend Oreille River. Consumption of NP <24 " should be limited to no more than 2 meals per month and NP >24 should not be consumed. Further testing for PCBs, PDBEs, and other contaminants is forthcoming. Providing northern pike to local food banks, although attractive from a public relations perspective, is an environmental injustice that is inadvisable. Therefore all northern pike collected during the suppression project will be composted through a company in Reardan, WA.
WE Agreement Type:
Contracted
Deliverable Specification:
We estimate that 2,000-4,000 northern pike will be removed from slough and backwater spawning locations between ice-off (March) and May 2nd. Effectiveness of that initial Phase I suppression effort will be assessed in early May with standardized spring pike index netting survey (SPIN). Target abundance indices developed for the reservoir are <1.73 NP/net in the southern 1/2 of the reservoir (Pioneer Park to Riverbend) and <0.5 NP/net north of Riverbend. If we meet our target abundance objectives in the initial effort then suppression will cease for the year. If targets are not met, suppression will continue until June (Phase II).
WSE Effective Budget:
$103,751
% of Total WSE Effective Budget:
29.67%
WSE Completion:
04/30/2015
WSE ID Continued From:
[Unassigned]
WSE ID Continued To:
[Unassigned]
Finite or Recurring:
Finite
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