Year Established: 2012 Start Date: 2012-03-01 End Date: 2013-02-28
Total Federal Funds: $19,266 Total Non-Federal Funds: $9,537
Principal Investigators: Matthew Wooller
Abstract: We propose using strontium (Sr) isotope (87Sr/86Sr) variation of tributaries of the Kvichak River to create a geo-spatial map of potential natal sources of Pacific salmon (e.g. sockeye salmon - Oncorhynchus nerka) originating from this watershed. We are working with students and teachers from schools in villages along the Kvichak River (Port Alsworth, Kokhanok, Newhalen, Levelock, Igiugig and Nondalton) to collect water samples from this river’s major tributaries. This will be a unique collaboration with Alaska village schools and will provide students and teachers the opportunity to be involved in the planning, preparation, execution and interpretation of results of a state of the art research project – a project that aims to help conserve a valuable resource to their communities. The Sr isotope map we generate will be used to track natal sources of salmon caught in mix-stock fisheries at the mouth of the Kvichak. Western Alaska Rivers, such as the Kvichak River, provide important spawning and rearing habitat for some of the world’s largest wild salmon populations. Salmon migrations maintain an important mechanism of nutrient transfer between marine and freshwater ecosystems and also represent an important food and cultural resource to Alaska’s coastal communities. The sustainability and resiliency of Pacific salmon stocks (e.g. Kvichak River sockey salmon) to perturbations, such as mineral development and fisheries, is dependent upon these stock’s inherent biodiversity. This biodiversity is in the form of multiple local breeding populations, which make up the stock and originate from geographically distinct parts of rivers, such as tributaries of the Kvichak. A State need exists to develop tools which can accurately identify Pacific salmon population structure at the level of breeding populations to aid in the conservation of salmon biodiversity. Our research aims to continue the development of a tool to distinguish salmon population structure at this level be relating 87Sr/86Sr compositions recorded in the calcium carbonate of salmon otoliths to river water compositions. A prerequisite to this approach is baseline geochemical measurements needed to characterize the strontium isotopic (87Sr/86Sr) variation within rivers, such as the Kvichak. To this end, this proposed research will create an ‘isotopic map’ of salmon natal sources within the Kvichak watershed. Additionally, we will use the herein proposed measurements to evaluate an a priori geo-spatial model developed in ArcGIS to predict 87Sr/86Sr intra-watershed variation. All of the funds in this proposal are dedicated to supporting: a) water collections done by students and teachers, and b) analyses to be conducted by a graduate student (Sean Brennan) in the Water and Environmental Research Center (WERC) at the University of Alaska Fairbanks (UAF). This proposed research will add significantly to our ongoing and previous work to characterize strontium isotope variation of Alaska Rivers. The ultimate goal of our study is to develop a technique, based on the hydro-geochemistry of otoliths to relate salmon stocks to the rivers they originated from, which will have practical applications in the management of water and salmon resources.