Consequences of trophic, foundational and engineering services provided by kelp KELP ECOSYSTEM communities

CONNECTIONS Maxwell D. Calloway The Evergreen State College Northwest Straits Commission Puget Sound Restoration Fund PREFACE:

• Nursery habitat • Trophic subsidies from detrital export • “Stock” open water fisheries • Increased biodiversity • Demonstrate the importance of kelp ecosystems for mid and high trophic level and commercially OBJECTIVE important fin-fish species. CONTRIBUTIONS TO NEARSHORE FOOD WEBS DIRECT GRAZING

• Not the most common. • Urchins are most famous example. • Puget Sound: • Kelp Crab (Pugettia Producta) • Littorinid snails (Lacuna vincta) • Amphipods • Abundances of mesograzers may have greater impacts than more conspicuous grazers. • Ratio of biomass to grazing rate. •

Photo Courtesy: Helen Berry, DNR; Wikimedia Commons DETRITAL PATHWAYS

Distal ends of blades Erosion = 17% - 100% of Plant itself is Support for erode  POC and annual NPP (Krause-Jensen & leaching DOC biofilms and DOC Duarte, 2016, Nature Geosciences) into the water, microbes DISLODGMENT

• Lower as proportion of NPP than erosion. • Export of kelp to pelagic, beach, continental shelves and deep ocean trenches. • Quickly colonized by marine and terrestrial invertebrates.

• 43% of annual NPP exported (Krause- Jensen & Duarte, 2016, Nature Geosciences)

Photo Courtesy: Linnaea Mallette, www.publicdomainpictures.net

STABLE ISOTOPE ANALYSIS

• ∂13C and ∂15N enrichment • ∂15N – trophic position • ∂13C – source of production

Figure Courtesy: Müldner, University of Reading, https://www.futurelearn.com/courses/archaeology/0/steps/15267 Herring Cod Kelp greenling

KDC: SIGNIFICANT CONTRIBUTION TO NEARSHORE FOOD-WEBS Rockfish

Cormorant

Seals

Modified from von Biela, et al. 2016, Estuarine, Coastal and Shelf Science BACK OF THE ENVELOPE

• Ground fish (rockfish, cod, greenling, sculpin) & juvenile herring • KDC = ~35 – 45% of biomass • No isotope data available for salmonids • Used KDC values of ground-fish for the purposes of this exercise

Statewide Puget Sound Net Economic Ground Fish $150,000 – $ 170,000 $4.4 – $5.25 million Salmon $2.5 – $3 million $2.6 – $3.1 million Herring $52,000 – $67,000 KDC Total $52,000 – $67,000 $2.65 – $ 3.17 million $7 – $8.35 million Total $148,000 $7.1 million $19.2 million

*All estimates calculated from WDFW Fisheries Economic Report 2008 ISSUES WITH ISOTOPES

• Difficult to differentiate POM signal from phytoplankton and kelp detritus (Miller & Page, 2012, Marine Biology) • ∂13C enrichment of POM increases closer to shore regardless • ∂13C enrichment trends with chlorophyll concentration and plankton growth rates. • Solution? • Use higher trophic level species, compare to kelp and kelp free areas.

Photo Courtesy: European Space Agency, http://www.esa.int/spaceinimages/Images/2012/01/A_southern_summer_bloom ROCKFISH ISOTOPES THROUGH TIME

• Bone collagen • ∂13C enrichment changes pre- and post- European contact in Haida Gwaii, B.C. • Due to urchin barrens following removal of sea otters.

Szpak et al. 2013, Archaeological and Anthropological Sciences FOUNDATIONAL CASCADES

Foundation species: one that increases community richness, abundance and trophic complexity. • Passive: • Increase volume of available habitat • Refuge & Nursery • Alter trophic dynamics • Food subsidies STRUCTURAL BENEFITS • Active: • Alter light availability • Ameliorate wave and current energy • Entrain water

Photo Courtesy: Glacier Bay National Park & Preserve STRUCTURAL DIVERSITY IS IMPORTANT

• Larger kelp = increased faunal abundance • Increased blade complexity = increased invertebrate biodiversity • Kelp provide three microhabitats (blade, stipe, holdfast) • Multistory canopies provide refuge and act a nursery habitat. Relationship between mobile macrofauna abundance and substrate volume (Christie et al., 2009, Marine Ecology Progress Series) INCREASED INVERTEBRATE ABUNDANCE

• Norwegian macrofaunal abundances > 500,000 per m2 • ~5x higher than abundances in seagrass and fucoid habitats • Amphipod & Shrimp > 8000 individuals per kg (wet weight) giant kelp fronds X 2.5 –5 kg per m2 • Benthic densities > 30,000 per m2 • Invert abundances increased regardless of floating canopy. • Beach wrack and continental shelf / deep sea mats

Miller et al. 2018, Proceedings B Christie et al. 2009, Marine Ecology Progress Series Photo Courtesy: NOAA Shade • Less macroalgal abundance • Greater patch diversity • More sessile invertebrates ENGINEERING EFFECTS Water motion Scour • Entrains water • Understory species • Ameliorates wave "sweep" substrate energy • Reduced sediment • Increases residence accumulation time of invertebrate larvae Reduced light Multiple canopies

Increased Entrain water & ENGINEERING invertebrate PRODUCTIVE increase substrate (mobile & sessile) SYSTEMS availability abundance

More midtrophic High level trophic species predators FISH

Kelp as nursery, refuge and hunting grounds WHAT WE KNOW SO FAR…

• Increased substrate: • Both in the water column and on the benthos • Increased invertebrates: • Copepods, amphipods, polychaetes, gastropods (and other mollusks), bryozoans, bivalves, • Fish mortality tied to size (growth rates) • Early growth rates extremely important for juvenile fish

Photo Courtesy: Wikimedia Commons REFUGE QUALITY IMPACTS GROWTH

• Study on barnacle eating Nucella snail • Predator: green crab • Refuge: rock crevices • Refuge quality influences impact of non-consumptive effects

Donelan et al. 2017, Ecology KELP AS REFUGE

Refuge use vs foraging by Cunner in the Gulf of Maine based on macroalgal community. Cunner prefer to use large blades of Saccharina latissima (O’Brien et al. 2018, Journal of Experimental Marine Biology and Ecology) • Herring, sand lance, surf smelt • Planktivorous • Calanoid copepods • Megalops FORAGE FISH • Barnacle larvae • Herring require macrophytes for spawn • All species use nearshore for spawning

Penttila 2007, Puget Sound Nearshore Partnership Photo Courtesy: Axel Kuhlmann, www.publicdomainpictures.net Tribble 2000, University of Washington Masters Thesis • YOY rockfish often most abundant finfish encountered during surveys in kelp forests • Juveniles hide in canopy and migrate down to understory and then to deep water habitats ROCKFISH NURSERIES • Helps avoid predation from large con-specifics and other predators • Kelp detritus transported to continental shelves likely important in promoting deep water benthic food webs

Singer 1985, Fishery Bulletin Love et al. 1990, Experimental Biology of Fishes Tolimieri et al. 2016, NOAA NMFS WCR Photo Courtesy: Clark Anderson/Aquaimages, Wikimedia Commons SALMON

• Puget Sound juvenile diet reflect differences between basins • North (Whidbey Basin): Terrestrial insects • South: Marine invertebrates • Adult Chinook and Coho rely on nearshore / coastal foodwebs • Based on stable isotope analysis • Salmon diet changes to incorporate more marine invertebrates in armored settings

Figure: Duffy et al. 2010, Transactions of the American Fisheries Society Johnson & Schinlder 2009, Ecological. Research SALMON USE KELP AS REFUGE

• Puget Sound juvenile outmigration and nearshore rearing period coincides with peak kelp productivity. • Early growth critical. • Juveniles will leave areas with inadequate foraging opportunities. • Juvenile coho observed to prefer floating kelp forests in the Strait of Juan de Fuca. • Juvenile salmon observed around the edges of overwater structures in urban waters.

Shaffer 2003, WDFW, Georgia Basin/Puget Sound Research Conference To f t et al. 2007 North American Journal of Fisheries Management Photo Courtesy: NOAA STRENGTHENING CONNECTIONS IN PUGET SOUND

• Stable isotope analysis • Need to be smart about how we choose to implement. • Continue to work through available association data • Synthesize diet studies • More direct observations • Remote cameras • Snorkel

Photo Courtesy: M. Calloway QUESTIONS?

Photo Courtesy: NOAA