Introduction
High inter-stock and inter-annual variation in adult returns of
Columbia River Basin salmonids, many populations of which are listed
under the Endangered Species Act (ESA), has led to an increased interest
in understanding the mechanisms that govern marine survival in the
Northern California Current (NCC). While many past studies have found
some correlations between marine survival and indices that describe
broad scale oceanographic or ecological phenomena (e.g., PDO or NPGO),
these indices have become increasingly non-informative due to
non-stationarity. In this project, we are seeking to re-examine the
relationship between marine survival and ocean conditions by developing
a statistical model that predicts marine survival based on the
spatiotemporal overlap between juvenile salmonids and key members of the
NCC food web. This requires integrating multiple data sources, primarily
different fisheries-independent surveys that sample different trophic
levels of the NCC food web.
How to navigate this website
Project
Background provides an overview of the literature on the marine
survival of Columbia River Basin salmon, and places our proposed study
within that context. Project
Description then describes our hypotheses as informed by our
conceptual understanding of the NCC food web, provides an overview of
the modeling workflow, and explains how we propose to use different data
sources in this project.
Under the “Survey Descriptions” tab, you will find an
overview of the four primary fisheries-independent surveys that
sample the pelagic NCC, followed by detailed descriptions of each: the
Juvenile
Salmon and Ocean Ecosystem Survey (JSOES), the California
Current Ecosystem Survey (CCES), the Pre-Recruit
Survey (PRS), and the Joint
U.S.-Canada Integrated Ecosystem and Pacific Hake Acoustic Trawl Survey
(Hake Survey). In the description of each survey, particular
emphasis is given to the trophic levels sampled by each survey as well
as their temporal and spatial extent, as these are key considerations
for integrating data from different surveys.
The “Exploratory Analyses” tab contains data summaries and other
exploratory analyses for each survey. So far, there are only preliminary
exploratory analyses available for the JSOES
Bongo Data and the JSOES
Trawl Data.
This website is dynamic and will be updated as the project
progresses. Please check back for updates!