Kelp Canopy South of the Jetty Shows a Second Year of Recovery
The February survey on the laboratory’s six permanent transects south of the Calder Bay jetty puts bull kelp canopy at 64% of the September 2018 baseline. The same transects measured 31% in August 2024, the summer after the marine heatwave. The series is published this month in Limnology and Oceanography by Naomi Okada, Elena Marchetti, and Samuel Pell.
What was counted
Each transect is 100 meters, fixed to shore marks set in 2011. Divers record stipe density, canopy cover, and understory every February and August. The February dive is the one that can be compared year to year without the late-summer storm losses. The 2026 count used the same four divers as 2024 and 2025, so the change is not a change in who was looking.
Water temperature on the transects during the 2024 heatwave peaked at 16.8°C in the first week of August. The 2018–2023 August mean at those marks was 13.1°C. The Harbor Data Observatory’s nearest sensor, Jetty South, recorded the same peak.
We are not calling the bed restored. We are saying the second year of cooler water produced a canopy you can see from the bluff again, and the transect counts agree with that.
Where the plants came back
- Transects 1 and 2, inside the jetty shadow, are at 81% and 77% of baseline.
- Transects 3 and 4, on open coast, are at 58% and 52%.
- Transects 5 and 6, nearest the outfall of Calder Creek, are at 44% and 41%. The creek mouth still carries the sediment pulse from the January 2025 slide.
What the laboratory will do this summer
The summer field term will repeat the August count and add a spore-density sample on transects 5 and 6. Undergraduate fellows are already assigned: four students, ten weeks, housed in Pilot House. Their posters go up at Kelp Week in May 2027, whether or not the paper is finished.
For students who want on this project
The summer 2027 fellowship application opens December 1, 2026. The kelp group will take two of the funded places. Write to the research office, not to the director’s personal mailbox. The appointment letter states the stipend, which is $5,400, and the boat-safety course you must finish before the first dive.
The full paper is Okada, Marchetti, and Pell, “Kelp canopy recovery after the 2024 marine heatwave on the southern Oregon shelf,” Limnology and Oceanography, 2026. A PDF is on the laboratory’s shelf in Hester Hall and in the library’s cruise-report archive.