Marine Carrying Capacity
State of the Salmon works to catalyze management actions that address marine carrying capacity issues. We actively promote productive and collaborative dialogue about marine production limitations to Pacific salmon as well as strategies to promote their long-term abundance, biodiversity and productivity.
Salmon conservation often focuses on activities within or adjacent to the freshwater ecosystems where Pacific salmon reproduce. But in the last two decades increasing attention has been paid to possible bottlenecks or production limitations in the marine environment where salmon spend the majority of their life feeding and maturing prior to returning to their natal streams.
At the same time, the global production of hatchery salmon in the North Pacific has reached approximately 5 billion releases per year, with significant increases reported in a number of areas. Active debate in recent years has focused on the interaction of marine limits to North Pacific salmon production and the potential risks that hatchery releases could present to wild salmon as a result of increased competition for limited prey resources. These questions and concerns are becoming more heightened as rapid global warming is expected to lead to dramatic deterioration of marine survival conditions in the North Pacific.
The trend toward lower marine survival has been documented in a number of salmon populations, particularly those along the southern distribution of their range. Modeling studies have been undertaken to address this issue, particularly by the Global Ocean Ecosystem Dynamics research program (GLOBEC), supported by the National Science Foundation and National Oceanic and Atmospheric Administration, and the MALBEC modeling project, supported by the Gordon and Betty Moore Foundation.
Significant policy inertia exists around this issue — one that could have significant implications to future sustainability and biodiversity of wild populations and to potential benefits derived from hatchery programs. Hatchery investments, benefits and impacts on wild populations have long represented politically contentious issues among Pacific Rim countries. The challenge to find policy solutions across various national jurisdictions, and issues of equity between who pays and who gains, must be addressed.
State of the Salmon's work on marine carrying capacity includes the following:
- expanding the global database of locations of hatchery facilities, pen release locations and spawning channels, attributed with production data where available, to document existing enhancement activities
- collaborating with other researchers on developing a practical policy gaming model to evaluate policy options and their costs and benefits
- collaborating with GLOBEC research group on applying oceanographic models to describe spatial patterns of growth potential for pink salmon across the coastal shelf of the Gulf of Alaska
- supporting relevant work of the North Pacific Anadromous Fisheries Commission, which is an appropriate forum for these issues to be addressed
- convening one or more workshops to help delineate the likely timing and location of marine limitations to salmon and to develop specific policy options and incentives that could be used by decision makers to effectively address the many issues surrounding this challenge