WERC graduate research assistant Andy Padilla will discuss his efforts studying the Bering cisco in relation to monitoring and fishery management.
Estimating stock composition of Yukon Delta Bering cisco harvest with otolith chemistry data
Bering cisco (Coregonus laurettae) are an anadromous whitefish species endemic to Alaska. Currently only three spawning populations are known: in the Yukon, Kuskokwim, and Susitna Rivers. Bering cisco rear in coastal estuaries and lagoons in Cook Inlet, and from Bristol Bay to Prudhoe Bay. A commercial fishery is developing in the lower Yukon River estuary where Bering cisco are the targeted species. Processor requests for a larger allocation indicate a desire for future fishery expansion. Bering cisco from both the Kuskokwim and Yukon River stocks are thought to be harvested in the fishery due to coastal currents. Relative abundance data from the Yukon River suggest a large population; however, no estimates are available for the Kuskokwim River. Subsistence harvest also occurs throughout their range. In order to monitor harvested populations appropriately, and prevent overharvest on an important subsistence resource, it is necessary to determine the population composition of the fishery.
This project aims to determine Bering cisco stock composi¬tion in the lower Yukon mixed stock commercial fishery. This will be accomplished through use of otolith and water chemistry, including strontium isotope composition. Our initial validation of this approach has involved collecting cisco from their different natal streams. We have compiled a collection of 118 otoliths from the Yukon, Kuskokwim, and Susitna Rivers, to examine whether they have significantly different otolith chemistry. In addition, several hundred mixed stock otoliths have been collected. Resulting data will provide additional tools for fishery managers in developing a population monitoring program and harvest strategy.
Courtesy Ora Schlei, USFS
Bering cisco male (top) from Susitna River, AK.
Friday Seminar Series
- What:Estimating stock composition of Yukon Delta Bering cisco harvest with otolith chemistry data
- Who: Presenter Andy Padilla
- When: 3:30-4:30 p.m. Friday, Dec. 2
- Where: 531 Duckering
Seminar schedule in PDF
