Biologists are anticipating a remarkable return of pink salmon in Puget Sound and Washington’s rivers this year, with estimates suggesting around 7.5 million fish could return.
This potential influx, while a positive indicator of salmon habitat health, is also raising concerns among scientists and fisheries managers.
Matt Bogaard, a specialist in chum, pink, and sockeye salmon with the Washington Department of Fish and Wildlife, explains that pink salmon, the smallest species among Pacific salmon, typically only come back to Washington in odd-numbered years.
Last year witnessed a scarcity of these fish, but forecasts for this year indicate a substantial increase.
“Throughout the North Pacific, pink salmon are the most abundant salmon species, comprising approximately 70% of all Pacific salmon,” Bogaard said.
In Washington, pink salmon populations can range from five to ten million in Puget Sound during their returning years.
The anticipated run this year is expected to place among the top five recorded returns since 1959, alongside a record return to the Fraser River, which could have significant implications for North Puget Sound fisheries.
To assess the adult returns, biologists collaborate with tribal co-managers, monitoring streams and counting spawning adults throughout the summer.
They also track juvenile salmon as they migrate to the ocean in spring, integrating various environmental factors—like ocean temperatures and freshwater conditions—into their forecasts.
Despite the encouraging numbers, the reason behind this anticipated boom remains a puzzle.
Bogaard notes that pink salmon appear to thrive in fluctuating ocean conditions, and due to their short life cycle, they effectively capitalize on environmental variations, producing large populations in favorable years.
However, this growth raises concerns for other salmon species, as overabundance of pinks can negatively impact their populations.
In some systems, high pink salmon numbers have been linked to declines in specific Chinook salmon stocks, which are crucial prey for Southern Resident orcas.
Research indicates that while higher pink salmon populations could benefit overall salmon numbers, they might harm the Chinook populations critical for orca survival.
Bogaard explains that orcas, particularly the Southern Resident population, exhibit a strong preference for large Chinook salmon, which deliver more nutritional value due to their higher fat reserves compared to pink salmon.
This dietary specialization makes it challenging for orcas to adapt to fluctuations in prey availability, preventing them from shifting to a less nutritious option such as pink salmon during peak runs.
Commercial fishers in the region also voice their concerns regarding the processing capacity for pink salmon.
While these fish can be a valuable resource, the unpredictability of their returns complicates planning and creates challenges in managing storage and freezer capacities.
“Pink salmon only appear in odd years, which makes it difficult for our processing systems to keep up during high abundance years,” said Bogaard.
As the salmon return season approaches, stakeholders in the fishing and conservation communities remain watchful, balancing the economic opportunities from the pink salmon run with the potential ecological ramifications.
This situation continues to highlight the interconnected dynamics between fish populations, their environment, and the human activities that depend on them.
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