Scientists from NWFSC / NOAA Fisheries collaborate with NMS staff scientists and vessel operators to conduct annual subtidal SCUBA surveys in kelp forests within the coastal waters of Olympic Coast National Marine Sanctuary. Researchers access study sites from La Push and Neah Bay, WA during late summer using two research vessels operated in tandem: OCNMS’s 52’ R/V Storm Petrel and NWFSC’s 24’ dive boat, R/V Minnow. The visual (SCUBA) dive surveys, derived from PISCO monitoring protocols, concentrate on five focal sites at two depths (5 and 10-m) to measure fish density, macroinvertebrate density, kelp density, and substrate type, rugosity, and cover.
We conduct SCUBA surveys at five kelp forest sites along the northern half of Washington’s outer coast annually in late July or early August. SCUBA divers survey benthic communities along 30 x 2 m belt transects in kelp beds at depths of 5- and 10-m using a quantitative standardized monitoring protocol (see Pondella et al. 2019; Claisse et al. 2012), targeting 12 transects per depth zone and site in a random stratified sampling design. Divers collect information in four categories: fishes, large mobile invertebrates, canopy-forming kelps, and substrate.
For fish data, divers visually assess abundance and total length of fish observed within a belt transect and within 2-m off the bottom for individuals greater than 5-cm total length. Rockfish species are recorded for all observations regardless of size. Underwater visibility is measured at each transect, and since accuracy is dependent upon visibility, observations of mobile species are excluded from the analysis when underwater visibility was less than 2-m.
For large mobile invertebrates, individuals greater than 2.5-cm in diameter or width are enumerated, including those found under prostrate algae and on algae up to a height of 1m above the substrate. This category includes species of sea urchins, sea star, sea cucumbers, crabs, bivalves, nudibranchs, etc. We include only species that are easily identifiable to avoid concerns about the detection of cryptic species. For abundant species the transect is broken into 10m segments and the distance at which 30 individuals were counted per segment is noted, to be used in expansion calculations. We also record sea urchin test diameter and sea star radius sizes. In some instances, we group species into functional taxonomic categories for analysis.
We count canopy-forming kelp species within each transect area. For Macrocystis pyrifera the stipes are counted when greater than 1m in height. Nereocystis luetkeana and Pterygophora californica plants with stipes greater than 30cm in height are included, along with other brown algae species greater than 30cm in overall length. We again use the segment subsampling for abundant species described for invertebrate species.
Substrate data are collected at each meter mark along the transect in a uniform point contact (UPC) survey method. We note substrate composition type (bedrock, boulder, cobble, sand), categorical degree of relief, and the organism responsible for holding primary space on the substrate at that location.
Claisse, J.T., D.J. Pondella II, J.P. Williams, J. Sadd. 2012. Using GIS mapping of the extent of nearshore rocky reefs to estimate the abundance and reproductive output of important fishery species. PLOS ONE. 7:e30290.
Pondella, D.J. II, S.E. Piacenza, J.T. Claisse, C.M. Williams, J.P. Wiliams, A.J. Zellmer, and J.E. Caselle. 2019. Assessing drivers of rocky reef fish biomass density from the Southern California Bight. Mar Ecol Prog Ser. 628:125-140.
Shelton, A.O., Harvey, C.J., Samhouri, J.F., Andrews, K.S., Feist, B.E., Frick, K.E., Tolimieri, N., Williams, G.D., Antrim, L.D. and Berry, H.D., 2018. From the predictable to the unexpected: kelp forest and benthic invertebrate community dynamics following decades of sea otter expansion. Oecologia, 188, pp.1105-1119.
Tolimieri, N., Shelton, A.O., Samhouri, J.F., Harvey, C.J., Feist, B.E., Williams, G.D., Andrews, K.S., Frick, K.E., Lonhart, S., Sullaway, G. and Liu, O., 2023. Changes in kelp forest communities off Washington, USA, during and after the 2014-2016 marine heatwave and sea star wasting syndrome. Marine Ecology Progress Series, 703, pp.47-66