Ecological effects of sea lice medicines in Scottish sea lochs Final report 9 February 2005 Scottish Association for Marine Science Plymouth Marine Laboratory Fisheries Research Services, Aberdeen SEAS Ltd Contributors Meiofauna: Mike Gee (PML); Hazel Needham (PML); Paul Somerfield (PML) Macrofauna: Tom Pearson (SEAS); John Blackstock (SEAS); Janet Duncan (SAMS) Littoral/sublittoral: Harry Powell; John Blackstock Phytoplankton: Pippa Sammes (FRS) Zooplankton: Kate Willis (SAMS) Chemistry: Pam Walsham (FRS); Linda Webster (FRS) Physical Modelling: Chris Cromey (SAMS); Phil Gillibrand (SAMS) Project Coordinator: Kenny Black (SAMS) Editing: Chris Cromey; Thom Nickell (SAMS); Kate Willis Ecological effects of sea lice medicines in Scottish sea lochs 2 of 286 TABLE OF CONTENTS 1 EXECUTIVE SUMMARY ..........................................................................................................................6 2 INTRODUCTION.......................................................................................................................................12 2.1 THE SEA LOCH ENVIRONMENT: PHYSICAL, BIOGEOCHEMICAL AND ECOLOGICAL BACKGROUND...12 2.2 AQUACULTURE IN SCOTLAND ...........................................................................................................13 2.3 SEA LICE.............................................................................................................................................13 2.4 SHORT REVIEW OF ECOLOGICAL EFFECTS OF AQUACULTURE...........................................................14 2.4.1 The discharges of waste nutrients................................................................................................14 2.4.2 Medicines and chemicals .............................................................................................................15 2.5 SEA LICE BIOLOGY AND MEDICINES USED TO CONTROL SEA LICE ....................................................15 2.6 ECOTOXICOLOGY OF SEA LICE MEDICINES........................................................................................15 2.6.1 Azamethiphos (Salmosan) ...........................................................................................................15 2.6.2 Cypermethrin (Excis)...................................................................................................................16 2.6.3 Emamectin benzoate (Slice) ........................................................................................................17 2.6.4 Teflubenzuron (Calicide) .............................................................................................................18 2.7 POTENTIAL EFFECTS IN ZOOPLANKTON.............................................................................................19 2.8 POTENTIAL EFFECTS IN PHYTOPLANKTON.........................................................................................19 2.9 POTENTIAL EFFECTS IN MEIOFAUNA..................................................................................................20 2.10 POTENTIAL EFFECTS IN LITTORAL SETTLEMENT ...............................................................................20 2.11 POTENTIAL EFFECTS IN SUBLITTORAL SETTLEMENT.........................................................................21 2.12 POTENTIAL EFFECTS IN MACROFAUNA..............................................................................................21 3 METHODS..................................................................................................................................................22 3.1 SITE SELECTION PHILOSOPHY ............................................................................................................22 3.2 SAMPLE COLLECTION AND ANALYSIS................................................................................................22 3.2.1 Zooplankton..................................................................................................................................22 3.2.2 Phytoplankton, nutrients and salinity ..........................................................................................23 3.2.3 Meiofauna.....................................................................................................................................24 3.2.4 Macrofauna...................................................................................................................................24 3.2.5 Uni- and multivariate analyses of faunal community structure..................................................25 3.2.6 Sublittoral settlement on suspended panels.................................................................................27 3.2.7 Littoral site assessment - shore fauna and flora ..........................................................................27 3.2.8 Sediment chemistry......................................................................................................................28 3.2.9 Hydrodynamic surveys.................................................................................................................31 3.2.10 Bathymetric surveys................................................................................................................32 3.2.11 DGPS drifting buoy surveys...................................................................................................32 3.2.12 Modelling.................................................................................................................................33 4 LOCH SUNART.........................................................................................................................................36 4.1 SITE DESCRIPTION..............................................................................................................................36 4.2 FISH FARM HISTORY, BIOMASS, CAGE POSITIONING AND MEDICINE USE .........................................38 4.3 HYDROGRAPHY..................................................................................................................................43 4.4 CYPERMETHRIN WATER COLUMN CONCENTRATIONS: EXCIS TREATMENT JANUARY 2002.............44 4.5 PREDICTED POST-TREATMENT CYPERMETHRIN WATER COLUMN CONCENTRATIONS......................46 4.6 PREDICTED POST-TREATMENT SEDIMENT CYPERMETHRIN CONCENTRATIONS ................................48 4.6 EMAMECTIN BENZOATE SEDIMENT CONCENTRATIONS: SLICE TREATMENTS MAY AND SEPTEMBER 2002 ............................................................................................................................................................54 4.7 PREDICTED POST-TREATMENT SEDIMENT EMAMECTIN BENZOATE CONCENTRATIONS....................56 4.8 ZOOPLANKTON...................................................................................................................................60 4.8.1 November 2000 Excis and Salmosan treatments........................................................................60 4.8.2 Zooplankton long-term monitoring .............................................................................................64 4.9 PHYTOPLANKTON ..............................................................................................................................69 4.9.1 November 2000 Excis and Salmosan treatment..........................................................................69 4.9.2 Phytoplankton long-term monitoring ..........................................................................................71 4.10 MEIOFAUNA .......................................................................................................................................75 4.10.1 Nematodes ...............................................................................................................................76 4.10.2 Meiobenthic copepods ............................................................................................................78 4.11 MACROBENTHOS................................................................................................................................79 4.11.1 Sediment conditions at Loch Sunart fish farm.......................................................................79 4.11.2 Macrofaunal distribution, abundance and structure...............................................................79 4.11.3 Analysis across surveys ..........................................................................................................86 Ecological effects of sea lice medicines in Scottish sea lochs 3 of 286 4.11.4 Conclusions .............................................................................................................................87 4.12 SUBLITTORAL SETTLEMENT ON SUSPENDED PANELS........................................................................87 4.13 LITTORAL SITE ASSESSMENT - SHORE FAUNA AND FLORA................................................................93 4.13.1 Barnacle (Semibalanus balanoides) populations and development......................................96 5 LOCH DIABAIG ......................................................................................................................................100 5.1 SITE DESCRIPTION............................................................................................................................100 5.2 FISH FARM HISTORY, CAGE POSITIONING, BIOMASS, AND MEDICINE USE......................................102 5.3 HYDROGRAPHY................................................................................................................................107