Water levels in Okanagan Lake are managed to provide a balance between fisheries, flooding, and other interests. Water levels must provide sufficient water to meet target lake levels for Okanagan Lake kokanee and downstream flow for sockeye salmon populations. Owing to a variety of factors, Okanagan River sockeye are the only significant remnant stock of more than a dozen anadromous salmon stocks that historically returned to Canada through the U.S. portions of the Columbia River.
The Okanagan Nation Alliance and Canadian Okanagan Basin Technical Working Group (COBTWG) identified improvements to Okanagan River flow management practices as one means of achieving significant sockeye production gains. With this goal in mind the Fish-Water Management Tool (FWMT), an Internet-accessible software application, was developed as the central tool for defining these improved water management practices. The FWMT enables water managers and fisheries scientists to combine best science subsystem models and integrate real‑time data to make daily/weekly decisions regarding Okanagan Lake Dam water releases to:
- minimize flood damage
- protect fisheries values (e.g. Okanagan Lake shore spawning kokanee eggs and alevin, and Okanagan River sockeye eggs and alevin);
- satisfy domestic and irrigation water supply demands;
- support recreation, navigation & tourism.
Key activities include:
- Sockeye spawner enumeration
- Kokanee shore spawning enumerations
- Deadpitch Survey
- In-lake sampling
- Fry emergence
Sockeye spawner enumeration & biosampling.
- count sockeye spawners by live (holding and spawning) + dead.
- count peak live plus dead: total redd: 10% dead date.
- count KO, CH (and all other fish species in the drive/walk counts at VDS)
- determine the kokanee shore spawning timing in Okanagan Lake
- determine 100% emergence of sockeye fry during spring freshet
- deadpitch sockeye for sex ratio and to determine the percentage of the run that is Skaha vs. Osoyoos lake stock, and use length to determine fecundity; spatially stratify samples upstream versus downstream of McIntyre (1% of dead sockeye u/s vs d/s);
- sample across run pre-,peak and late run (peak at 10% dead) collect length, sex and otolith of 1500 (or 1% run) sockeye; over 4-5 sample sessions
- process biosample data for age at length and fecundity at age for sockeye