White sturgeon Acipenser transmontanus, like many sturgeon species worldwide, have suffered declines in abundance and distribution. The subpopulation of white sturgeon in the upper Columbia River above Grand Coulee Dam is classified as Critically Endangered (CE) by the IUCN and listed as endangered under the Canadian Species At Risk Act (SARA) due to persistent recruitment failure. Recruitment failure in the upper Columbia River between Grand Coulee and Hugh Keenleyside dams (the Transboundary Reach) white sturgeon population was first documented during studies conducted in the early 1990’s in the Canadian portion of the Reach (the Keenleyside Reach). Similar results were obtained in 1998 in the Washington portion of the Reach (the Roosevelt Reach). In response to increasing concerns over the threat of extinction, the Upper Columbia White Sturgeon Recovery Initiative (UCWSRI) was formed in 2000. The UCWSRI is an international organization with members from state, provincial, and federal fisheries agencies, Canadian First Nations, U.S. Tribes, and industry stakeholders in British Columbia and Washington State. The Initiative produced an Upper Columbia White Sturgeon Recovery Plan (UCWSRP) that is compatible with the ESA and SARA legislation. The goal of the UCWSRI, as defined in the UCWSRP, “is to ensure the persistence and viability of naturally reproducing populations of white sturgeon in the upper Columbia River and restore opportunities for beneficial use if feasible.”

The White Sturgeon Enhancement Project (WSEP) is a new project that was identified in the 2008 Fish Accords Memorandum of Agreement between the Colville Confederated Tribes (CCT) and the FCRPS Action Agencies. The project is intended to complement the existing recovery effort by addressing factors limiting recruitment of white sturgeon in the Transboundary Reach. This will be achieved by implementing the UCWSRP in direct coordination with the UCWSRI partners and Lake Roosevelt Co-Managers. Thus, the project goal is that of the UCRWSRI (above). The project specific objectives are consistent with the short- and medium-term objectives in the UCWSRP. The CCT WSEP objectives are to 1) monitor the status and trend of the Transboundary Reach white sturgeon population, and 2) identify factors limiting natural recruitment of white sturgeon in the Transboundary Reach.

Objective 1 - Monitor Population Status
Objective 1 is consistent with the UCWSRP short-term objective to assess the population status of white sturgeon in the Transboundary Reach. Population status and trend monitoring, and associated database management, are considered core components of the recovery effort. In 2018, the CCT, under this project, will supply a boat and crew to support the population monitoring efforts that will be led by the Spokane Tribe’s Lake Roosevelt Sturgeon Recovery Project (1995-027-00) in Washington and by BC Hydro in British Columbia. Population monitoring will consist of setline stock assessment surveys to estimate abundance, growth, and condition, as well as fall sub-yearling gill net surveys to monitor for natural recruitment.

The historical, current, and future work related to Transboundary Reach white sturgeon has generated, and continues to generate, a substantial amount of data. Thus, the CCT under this project lead the development of an integrated UCWSRI relational database management system that encompasses data collected by all of the UCWSRI partners to assist with research, monitoring, and management activities. In 2018, the CCT WSEP will subcontract and lead the hosting and maintenance/management of the UCWSRI database management system and website.  The UCWSRI database could form the framework for a Columbia Basin White Sturgeon Data Management System such as that developed for pallid and shovelnose S. platorynchus sturgeon activities in the Missouri River system – the Sturgeon Information Management System (SIMS).

Objective 2 - Identify Factors Limiting Recruitment
Objective 2 is a component of the UCWSRI Recovery Plan's set of medium-term objectives and seeks to determine survival limitations (bottlenecks) acting on remaining supportable populations and establish feasible response measures. The bulk of sturgeon larvae produced in any given year emerge from the substrate to begin feeding in the upper river-reservoir transition zone of the Roosevelt Reach during July. The timing of larval emergence generally coincides with rapidly declining river discharge and reservoir refill - factors that collectively may limit downstream dispersal. Sampling efforts to date indicate that larvae are not found downstream of the transition zone. Conditions in the transition zone are apparently not conducive to survival as evidenced by lack of subyearling captures during fall gill net surveys. However, limited recruitment does occur in years- most recently 1997 - when very high river discharge (>5,663 m3 s-1) coincides with emergence of first feeding larvae. This suggests dispersal may represent a primary mechanism influencing survival and indicates that suitable rearing habitat may exist in areas downstream from the river-reservoir interface.

In order to evaluate the larval transport/habitat mis-match hypothesis, in 2018  the CCT and subcontractors will fill data gaps in previous hydrographic surveys of the upper Roosevelt Reach to characterize bathymetry and substrate typology. Habitat characterization is the foundation of the habitat modeling work completed under this project. If 2017 modeling results indicate the need for refinements to the habitat data set, we will fill those data gaps.

In 2018, we will implement the second year of investigation of the larval transport/habitat mis-match hypothesis by collecting and marking naturally produced larvae from the river-reservoir transition zone and translocating them downstream in to the upper reservoir where sampling efforts to date have indicated larvae are absent most years.  Survival of translocated larvae to fall subyearling and fall yearling ages will be evaluated according to captures during annual fall gill net recruitment indexing surveys. Experimental fish will be released into areas where naturally produced fish are known to be present each year (China Bend) and into areas further downstream in the upper reservoir

No sampling outside the US will be conducted under this project, although data will be provided to a trans-boundary database to compliment a holistic management strategy across the multi-nation population distribution.

NOTE: Some data collected in this contract is analyzed by is collected as part of a coordinated Transboundary stock assessment and supports aquaculture M&E, and therefore some data analysis is conducted by the Spokane Tribe of Indians (Project 1995-027-00).