Forecasting Pink Salmon Production in Southeast Alaska Using Ecosystem Indicators in Times of Climate Change

Abstract

Researchers in Alaska have provided accurate pre-season annual forecasts of pink salmon harvest to resource stakeholders of Southeast Alaska (SEAK) in times of climate change. Since 1997, the Southeast Alaska Coastal Monitoring project has collected biophysical data associated with seaward migrating juvenile salmon from May to August, and it has used these data along with larger basin-scale indexes to forecast SEAK pink salmon returns via regression and ecosystem metric models. In nine of the past eleven years (2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012)(2013)(2014), predictions from linear regression models ranged 0-17% of actual harvests, an average absolute forecast deviation of 10%. The primary explanatory variable was juvenile pink salmon peak catch. In some years, models included secondary variables to improve fi t. A supplemental modeling approach was tested recently to better inform stakeholders. This approach incorporated both an annual rank score forecast outlook based on ecosystem metrics, and a visual stoplight color-code graphic. Accurate pre-season salmon forecasts and descriptive outlooks from this applied research has increased economic effi ciency of the fi sh processing industry, enabled managers and resource stakeholders to anticipate harvest with more certainty, helped promote resource sustainability, and provided insight into ecosystem mechanisms related to pink salmon production in a changing climate.

Technical Report 11

“…The pink salmon harvest forecast model is based on a juvenile abundance index (from surface trawl surveys) adjusted for 120 temperature (Fig 4). Information on juvenile growth condition, diet, prey availability, and climate indices are included as ecosystem considerations of the forecast (Orsi et. al.…”

The Use of Marine Ecosystem Metrics for Preseason Forecasts of Salmon Harvest

“…The pink salmon harvest forecast model is based on a juvenile abundance index (from surface trawl surveys) adjusted for temperature (Fig 4). Information on juvenile growth condition, diet, prey availability, and climate indices are included as ecosystem considerations of the forecast (Orsi et. al.…”