Threats to blue mussels — a European risk analysis

Ane Timenes Laugen Centre for Coastal Research (CCR), Universitetet i Agder, Kristiansand

NAEMO, Oban, 2019-10-30 Acknowedgements

•Åsa Strand, IVL Swedish Environmental Institute

•Kristina Svedberg, IVL & University of Gothenburg •Matthias Obst & Jon Havenhand, University of Gothenburg [Why] are blue mussels in decline? Human disturbance

Coastal exploitation/ shoreline hardening • Direct damage (anchoring etc.) • Sediment dispersal & noise during construction Boat traffic • Turbulence (wave exposure, sediments) • Direct damage (anchoring etc.) • Noise Pollution • Engines • Toilets • Antifouling

http://havsmiljo.se/media/fritidsbatars_miljopaverkan.pdf; https://en.wikipedia.org/wiki/Seawall#/media/File:Seawallventnor.jpg https://balticeye.org/sv/livsmiljoer/kustmiljobloggen/fritidsbatar-och-undervattensnatur/ Qualitative threat analysis

Svedberg 2019. MSc thesis, Gothenburg University Eutrophication

Increased presence of epibionts/fouling • reduced hard surface areas for settlement • increased energy allocation to byssus production • increased risk for dislodging

Increased abundance of food 1 cm

Buschbaum, C., & Saier, B. (2001). Growth of the mussel Mytilus edulis L. in the Wadden Sea affected by tidal emergence and barnacle epibionts. Journal of Sea Research, 45(1), 27–36 Biotoxins / pollution

Algal toxins • reduced risk of algal blooms with decreased eutrophication • increased risk of algal blooms with increasing temperatures

PAH • negative effect on M galloprovincialis (Cajaraville et al 1995) • little knowledge about effects of PCB, HCB, DDT

PCB, HCB, DDT, others • more or less unknown Climate change

Ocean warming • growth/reproduction • risk of disease • distribution range • epibionts/fouling

Extreme weather • nutrient runoff • disturbance (ice, sediments, storms)

Ocean acidification • growth/reproduction/survival

Laugen, Strand, Havenhand, Obst (in prep) Invasive

Pacific (Magallana gigas) • competition (space/food) • protection (fouling/predation) • settling surface

Sea walnut ( fornicata) • competition (space/food)

Common slipper shell (Mnemiopsis leidiy) • larval mortality Predation/pathogens

Birds • eider populations varies in space and time

Invertebrates • crabs and sea stars prefer mussels to pacific

Pathogens • spatiotemporal variation in outbreak risk • expected to increase with climate change

Strand, Fredriksson & Laugen (in prep) Extending the risk assessment

•From qualitative to quantitative whenever possible •Multidisciplinary (aquaculture/wild-harvest/ecology/evolution etc.)

•International (from regional to European/North Atlantic)

•Call for collaboration