Bull Kelp Monitoring
Floating bull kelp (Nereocystis luetkeana) is important habitat for marine invertebrates, such as pinto abalone, and marine fishes, including forage fish and the endangered rockfish bocaccio (Sebastes paucispinis). However, the distribution and area of bull kelp beds in Puget Sound is not regularly monitored, so changes in abundance of this critical habitat would be poorly documented.
In 2015, Island County MRC collaborated with the Northwest Straits Commission and other County MRCs to begin testing and refining a boat-based survey protocol for bull kelp beds. Island County volunteers used kayaks to access the beds, collect temperature and depth estimates, and plot the perimeter of beds with handheld GPS units. In 2016, volunteers surveyed five nearshore kelp sites (four near Whidbey, one near Camano; see figure) for seasonal changes in bed area and conditions.
Several observations from 2016 have implications for bull kelp beds and monitoring efforts.
- Near surface temperatures were much higher (approaching 17°C) at Polnell Point and Lowell Point (Camano Island State Park). These high temperatures can be stressors for kelp growth and health.
- Kelp bed areas did not grow at the same rate across the sites. This suggests that each bed has different growth characteristics, and extrapolating growth information to unmonitored beds might not be valid.
- Kelp beds are inhabited extensively by different invertebrate and fish throughout the growing seasons, ranging from Dungeness crab zoea, forage fish, and marine birds.
See some of the inhabitants of bull kelp beds!
- Forage fish (mostly herring) and shiner perch
- Shiner perch and a tube snout (at 20-23 seconds)
- Submerged aquatic vegetation beneath bull kelp with shiner perch, forage fish, and kelp perch (at 26 and 40 seconds)
- Kelp crab hiding among kelp blades
In addition to boat-based kelp bed surveys, Island County MRC is exploring the opportunity that aerial imaging can offer, especially using different wavelengths (e.g., infrared, visible light). This could allow a complete inventory of the locations of kelp beds along Island County’s more than 200 miles of shoreline.