2010:1 Intercalibration of fish assessments of ecological status in Northern lakes – results from a pilot study Interkalibrering av fiskbaserade bedömningar av ekologisk status i nordiska sjöar – resultat från en pilotstudie KERSTIN HOLMGREN, ANDERS KINNERBÄCK Swedish Board of Fisheries, Institute of Freshwater Research, Sweden MIKKO OLIN Aquatic Sciencies, University of Helsinki, Finland TRYGVE HESTHAGEN, RANDI SAKSGÅRD Norwegian Institute for Nature Research, Norway FIONA KELLY Central Fisheries Board, Republic of Ireland MARTTI RASK Finnish Game and Fisheries Research Institute, Finland Ansvarig utgivare: Axel Wenblad Redaktionskommitté: Ingemar Berglund, Joep de Leeuw, Kerstin Holmgren, Anders Kinnerbäck, Mikko Olin, Trygve Hesthagen, Randi Saksgård, Fiona Kelly, Martti Rask För beställning kontakta: Fiskeriverket Box 423, 401 26 Göteborg Telefon: 031-743 03 00 [email protected] Kostnad 50 kr, inklusive moms. Porto tillkommer. Rapporten kan också laddas ned från Fiskeriverkets hemsida: www.fiskeriverket.se ISSN 1404-8590 2010:1 Intercalibration of fish assessments of ecological status in Northern lakes – results from a pilot study Interkalibrering av fiskbaserade bedömningar av ekologisk status i nordiska sjöar – resultat från en pilotstudie KERSTIN HOLMGREN, ANDERS KINNERBÄCK [email protected]; [email protected] Swedish Board of Fisheries, Institute of Freshwater Research, Stångholmsvägen 2, SE-178 93 Drottningholm, Sweden MIKKO OLIN [email protected] Aquatic Sciencies, Department of Biological and Environmental Sciences, Biocenter 3, POB 65, FI-00014 University of Helsinki, Finland TRYGVE HESTHAGEN, RANDI SAKSGÅRD [email protected]; [email protected] Norwegian Institute for Nature Research, Tungasletta 2, NO-7485 Trondheim, Norway FIONA KELLY [email protected] Central Fisheries Board, Swords Business Campus, Balheary Road, Swords, Co. Dublin, Republic of Ireland MARTTI RASK [email protected] Finnish Game and Fisheries Research Institute, Evo Game and Fisheries Research Stn, FI-16970 Evo, Finland 2010:1 4 2010:1 SUMMARY 6 SAMMANFATTNING 7 INTRODUCTION 8 General approach 9 Differences in fish sampling methods 9 Differences between assessment methods 9 MATERIAL AND METHODS 11 RESULTS 14 Lake characteristics and pressures 14 Comparison of national assessment tools 17 Additional issues 21 DISCUSSION 22 Data compilation experiences 22 Comparability of assessments and pressures 22 Additional experience of the data exchange 23 Concluding remarks 24 ACKNOWLEDGEMENTS 25 REFERENCES 26 ANNEX I 28 Summary of the Finnish assessment criteria – EQR4 28 ANNEX II 31 Summary of the Swedish assessment criteria – EQR8 31 Short guide for practical use of EQR8 31 Prerequisites of status assessment using EQR8 31 Included fish metrics 32 Procedure from metric values to combined index (EQR8) 32 Classification of ecological status 33 Guide for interpretation of low metric values 33 Fish species found in Swedish freshwaters 34 ANNEX III 36 Fish data sets for comparison of national methods 36 5 2010:1 Summary A Water Framework Directive for European types”, used for intercalibration of other water bodies is in effect since December biological elements during 2004-2007. Most 2000. The objective is to ensure at least of the lakes included in the study were, good ecological status of all water bodies however, grouped into ten “Finnish lake by 2015. The fish fauna and other biologi- types”. Preliminary analyses revealed only cal quality elements should be monitored weak or insignificant correlation between for assessment of whether the objective the Finnish and Swedish index values, is achieved. Many national methods have within most lake types compared. The Finn- been developed for assessment of ecological ish EQR4 failed to detect many impacted status in lakes, rivers and coastal waters. In lakes from Ireland and Sweden, while the December 2011, intercalibration of all Euro- Swedish EQR8 appeared to be too conserva- pean “monitoring systems” for ecological as- tive, especially for reference lakes with low sessment of lakes, rivers and coastal waters species richness. Each of the fish indices re- is planned to be finalised. The aim is to en- sponded nonlinearly to gradients of pH and sure consistency and comparability between total phosphorus, probably because the data status assessments in similar water bodies, set included a complex mixture of lakes independent of member state affiliation. In with contrasting pressures (e.g. acidifica- a pilot study 2008-2009, Finnish and Swed- tion and eutrophication). The Irish data set ish fish indices were applied to gillnet data comprised many lakes with low proportions (EN 14 757) from Finnish, Irish, Norwegian of native species. In contrast, native species and Swedish lakes (89–305 lakes per mem- made up 90–100 % of the fish biomass in ber state). The Finnish and Swedish fish the Finnish, Swedish and Norwegian lakes. indices are based on four and eight metrics, In the upcoming intercalibration process, respectively, describing different aspects agreement is needed on which specific pres- of fish abundance and species composition. sures are to be detected in which set of com- The index names EQR4 and EQR8 reflect parable lake types, and then some robust their expressions as ecological quality “Northern fish metrics” must be found for ratios, with values between 0 and 1. The these pressure and lake type combinations. present dataset included only a few lakes within the seven “Northern intercalibration 6 2010:1 Sammanfattning EU.s ramdirektiv för vatten trädde i kraft 2004-2007. Däremot kunde de flesta sjöar i december 2000. Fiskfaunan är en av de grupperas i någon av tio ”finska sjötyper”. biologiska kvalitetsfaktorer som ska över- Preliminära analyser uppvisade bara svaga vakas, för att bedöma om målet minst god korrelationer mellan finska och svenska ekologisk status har uppnåtts år 2015. indexvärden, inom de flesta jämförbara Sedan direktivet infördes har många sjötyperna. Finska EQR4 misslyckades nationella metoder utvecklats för bedöm- med att särskilja många av de påverkade ning av ekologisk status i sjöar, vattendrag sjöarna från Irland och Sverige, medan och kustvatten. I december 2011 ska alla svenska EQR8 uppenbarligen var för kon- Europeiska metoder för bedömning av servativt, speciellt för referenssjöar med låg ekologisk status vara interkalibrerade. artrikedom. Båda fiskindexen uppvisade Syftet är att få konsekventa och jämförbara icke-linjär respons i gradienter av pH och bedömningar av status i liknande vattenfö- totalfosfor. Det berodde sannolikt på att rekomster på olika sidor av nationsgränser. datasetet bestod av en komplex blandning I en pilotstudie 2008-2009, beräknades av sjöar med kontrasterande påverkan finska och svenska fiskindex på data från (t.ex. försurning och eutrofiering). Det provfiske med Nordiska översiktsnät irländska datasetet innehöll många sjöar (EN 14 757) i finska, irländska, norska och med låga andelar av inhemska fiskarter. I svenska sjöar (89–305 sjöar per land). De alla de finska och svenska sjöarna utgjor- finska och svenska fiskindexen baseras på des istället fiskbiomassan till 90–100 % fyra respektive åtta fiskindikatorer, som av inhemska arter, liksom i de flesta av de beskriver olika aspekter av abundans och norska sjöarna. I den kommande interkali- artsammansättning. Indexnamnen EQR4 breringsprocessen behövs enighet om vilka och EQR8 speglar att de uttrycks som eko- specifika typer av påverkan som ska kunna logiska kvalitetskvoter (ecological quality upptäckas i vilka jämförbara sjötyper. ratios) med värden mellan 0 och 1. Det Några robusta “nordiska fiskindikatorer” aktuella datasetet inkluderade bara några bör identifieras för respektive kombination få sjöar inom de ”nordiska interkalibre- av påverkan och sjötyp. ringstyper” som användes i interkalibrering av andra biologiska kvalitetsfaktorer under 7 2010:1 Introduction A Water Framework Directive for European on specific combinations of intercalibration water bodies is in effect since December type, biological quality element and pres- 2000. The objective is to ensure at least sure (or complex of pressures). The new good ecological status of all water bodies by guidance for the intercalibration process 2015. The fish fauna and other biological 2008-2011 was adopted at the WG Ecologi- quality elements should be monitored to cal Status (ECOSTAT) meeting 1-2 October verify that the objective is achieved (Eu- 2009. ropean Commission 2003a). The biological Some parts of the intercalibration proc- sampling methods should, when possible, ess were completed during the first round follow European standards. Measured 2004-2007 (Poikane 2008). However, fish in parameters should be indicative of species lakes was not officially included until a one- composition and abundance, and for fish the year pilot project started in October 2008. age structure should also be considered. The The pilot project is compiling a Pan-Euro- ecological status should be assessed as high, pean database to develop common metrics good, moderate, poor or bad, where high to facilitate intercalibration of national status means a biological community with methods, if they differ in data acquisition no or minor deviation from type-specific and numerical evaluation. Further prepara- reference conditions (European Commission tory work is being implemented within geo- 2003b). The typology admits that reference graphical intercalibration groups (GIG’s). conditions may differ depending