Marine Scotland Offshore Renewable Salmon Research

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1 Marine Scotland Offshore Renewable Salmon Research Stuart Middlemas, Iain Malcolm, Jason Godfrey, James Orpwood, & John Armstrong Marine Scotland Science Freshwater Laboratory

2 MSS Marine Renewable Research Work undertaken as part of the Marine Renewable Energy program Too early to present results of any of the work However, the talk will show what Marine Scotland is currently doing, and the strategy behind this work

3 Outline Atlantic salmon in Scotland s coastal waters Current state of knowledge Background on Marine Renewables Investigating the potential for an impact Plans for increasing current knowledge Summary

4 Importance of Atlantic Salmon Species of high economic and conservation value Anglers estimated to spend 73 million/year in Scotland Protected under EU Habitats Directive Concerns regarding declining abundance throughout range

5 Potential Anthropogenic Factors

6 What type of information is required? Which parts of coastal zones are used by salmon Times that salmon are present in the coastal zone How do they use the water column What do they eat Such information is required to inform management Answer questions such as what will the impact of developments be on salmon stocks (especially SACs) Detailed information on migratory routes and depths Review by Malcolm et al.

7 Inshore migration of returning adults Adults return throughout the year Highest numbers in summer, but valuable stocks in e.g. spring Information through physical tagging Known capture and recapture points Overall picture is complex Salmon return to coast Travel to river of origin No consistent patterns of movement Limitations of approach Only have start and end points Constrained by location of recapture points

8 Background: Type of renewables devices Number of different type of marine renewable devices are being developed/deployed Wave devices Offshore wind farms

9 Background: Type of devices Different types of tidal turbines

10 General schematic used to evaluate potential impacts Overlap yes Mechanisms yes no no yes Limited concern Mitigation no Population status Potential Issue IMPACT

11 Overlap Which parts of coastal zones are used by salmon When salmon are present in the coastal zone How do they use the water column Should there be concern about tidal turbines in the Pentland Firth? Previous work suggests salmon migrate through this area Don t know fine scale spatial use, or what depths they are swimming at MeyGen tidal stream project

12 Overlap Information required on the migratory routes and swimming depths of salmon Potentially some read-across from studies in other countries: swimming depths likely to be the same between areas? (but careful extrapolating between different environments) Difficult to get detailed information for post-smolts Only possible to get some information now due to miniaturisation of tag technology Satellite tags open up new possibilities of collecting this information for adult salmon

13 Overlap Satellite tags Archival tags/data storage, stores depth information Pop-off: gives position during migration and allows interpolation of tracks Published work on eels Methodology not perfect Studies underway on salmon Norway/Ireland/Iceland/Denmark/ Greenland Trials planned for Scotland in 2013 Aarestrup et al. (2009) Science

14 Mechanisms Plausible ways renewables developments could impact on salmon Three main candidates 1. Collision risk 2. Noise 3. Electromagnetic Fields

15 Mechanisms: Collision Risk of collisions between salmon and marine renewable developments (especially tidal turbines) Collision (strike) can cause Direct mortality (injury) Indirect mortality (disorientation and predation) Collision risk studied for birds and windfarms (e.g. SNH advice)

16 Mechanisms: Collision Collision modeling requires information on Numbers of fish swimming through turbine blade Numbers of fish migrating through area (and origins) Migratory routes of these fish Swimming depth Location/number of turbines Probability of fish swimming through blade being hit Swimming speed and size of fish Size and speed of blade Avoidance behaviour?

17 Mechanisms: Collision Investigated using a computational fluid dynamics model for examining collision risk 2 phase approach 1. Set parameters and modelling approach 2. Undertake modelling Technical problems with the physics/maths of the model so was not progressed to Phase 2.

18 Mechanisms: Noise SNH commissioned review by Gill et al.2012 (Journal of Fish Biology 81, ) Paucity of information on noise generated by Marine Renewable developments Construction noise likely to be the most substantial Cumulative effects are possible Considerable uncertainty over the response of diadromous species to underwater noise

19 Sound threshold Mechanisms: Noise MSS has commissioned a series of projects to: 1.Measure auidograms for salmon, sea trout and eels to improve understanding of their hearing 2.Assess the behavioral response of caged fish to noise associated with pile driving 3.Model the consequences of salmon exposure to piling and operational noise Frequency (Hz) Salmon audiogram Hawkins & Johnstone 1978

20 Mechanisms: Electromagnetic Fields SNH commissioned review by Gill et al.2012 (Journal of Fish Biology 81, ) Diadromous fish can use the Earth s magnetic field for direction and orientation during migration EMF from subsea cables may interact with migrating fish (especially eels) Not necessarily biologically important 2 types of EMF AC and DC

21 Testing the response of salmon smolts to AC EMF Experimental work being undertaken in the tank facilities in Aberdeen Aim is to examine the effect of AC EMF fields on swimming behavior Annular tank Salmon post-smolts swimming round tank Experiments also undertaken with silver eels Tank diameter of 9.8 m

22 Experimental setup Tank partitioned into two Movements between different sides through 4 circular openings (2 on each side of the partition) The openings are connected to an AC EMF generator AC EMF Generator

23 EMF generated in openings Experimental setup Range of field strengths can be produced How often do smolts go through the openings when the EMF field is present and when it is absent? Startle/avoidance response AC EMF Generator

24 Progress 18 trials undertaken with salmon post-smolts 64 hours of camera footage currently being studied Trials with eels also underway Video Cameras Openings Experimental set-up Annular tank

25 Mitigation: Electromagnetic Fields EMF levels drop off rapidly within a few meters away from the cables, animals need to be reasonably close in order to be impacted Potential impact of EMFS can be mitigated against by burying the cables Burying cables is costly, but is being considered for security reasons

26 Other Mechanisms There are also unknown unknowns there are things we do not know, we do not know Donald Rumsfeld There may be some mechanisms that may not be known at the moment which may impact on salmon populations e.g. changes to predators/prey caused by renewables developments which have a knock-on effect for salmon populations How to deal with unknown unknowns?

27 Monitoring of Populations One way to deal with unknown mechanisms is to monitor the populations to see if there are any changes associated with renewable developments Three main type of data collected on salmon populations Catches Electrofishing Counters

28 Monitoring of Populations Are we in a position to show whether renewables does/does not have an impact? Population data are usually noisy Total Scottish rod catch What levels of differences can be detected by catches and electrofishing data? (How sensitive are they) Contract to undertake power analysis to answer this question for electrofishing and catch data in the Solway associated with Robin Rigg wind farm development

29 Monitoring of Populations Properly calibrated and maintained counter data more reliable than catches (fewer assumptions) However, counters traditionally associated with in-river structures Weir Dam MSS examining possibility of using new technology such as sonar to count fish Image of Chinook salmon from Didson camera

30 Summary: How it all fits together Satellite tags Overlap EMF Collision Noise yes Mechanisms yes? no no yes Limited concern Mitigation Population Monitoring no Potential Issue Counters Catches

31 Final Thoughts Challenges for salmon Opportunities to find out more about salmon in inshore areas Information for renewables Wider applications Professor Audun Rikardsen, University of Tromsø releasing a satellite tagged salmon (Salmotrack) Thank you for listening