Mammals

A new report from the Puget Sound Ecosystem Monitoring Program says climate change altered the base of Puget Sound's food web in 2018, diminishing microscopic phytoplankton necessary for marine life. Scientists also observed lower abundances of fish, seabirds, and marine mammals.

A 2019 article in the Journal of Wildlife Diseases looked at trace element concentrations of heavy metals in the livers of harbor seals that died and stranded in the San Juan Islands. The study indicated exposure to trace elements (naturally occurring, human-introduced, or both) in the Salish Sea; however, the study reports that trace element toxicity is not a major threat to harbor seal health.

Officially known as West Coast transients but increasingly referred to as Bigg’s killer whales, these marine mammal-eating orcas (Orcinus orca) are spending increasing time in the Salish Sea to consume their marine mammal prey including harbor seals, Steller sea lions, and harbor and Dall’s porpoise. They range from Southeast Alaska to California, but over the last 15 years more members of the population are spending increasing time in the inland waters of Washington State and British Columbia (Houghton et al. 2015, Shields et al. 2018). They have no predators (except perhaps occasionally other Bigg’s killer whales - see Towers et al. 2018), but are at risk from anthropogenic effects, including toxics and noise pollution (Ford et al. 2007).

In July, the recent trends of warm, dry conditions lessened; however, river flows remain low. Extensive macroalgae drifted through South and Central Sound and washed up on beaches. Macroalgae growth is fueled by excessive nutrients and sunshine. When it washes onto the beach, it is called beach wrack, and it can be a health risk to beachgoers because of bacteria it can harbor. From our aerial photography, we saw that Southern Hood Canal looks tropical because of a bloom of coccolithophores coloring the water turquoise. Schools of fish congregate in South Sound and southern Hood Canal. Jellyfish are abundant in Quartermaster Harbor.

A 2014 paper in the journal PLoS ONE examines differences between foraging behavior of harbor seals based on haulout site locations, seasons, sexes and times of day. The authors hypothesize that these factors may help explain the variability in diet among harbor seals observed at different haul-out site groups in the Salish Sea. 

Warm and dry conditions this spring are predicted to persist into summer, resulting in saltier and warmer than normal Puget Sound water conditions. Early upwelling and a premature melt of the snowpack means nutrient-rich ocean water likely already entered Puget Sound. This sets the stage for a lot of biological activity. From the air, it is obvious that the productive season is in full swing. We saw large algae blooms in Central Sound along with abundant Noctiluca.  Huge numbers of anchovies were documented in Case Inlet and other finger inlets in South Sound, attracting hundreds of marine mammals.