Fletcher, Janice M.

James, J. Ben

Winfield, Ian J.

English

NERC Open Research Archive

  CEH LANCASTER LANCASTER ENVIRONMENT CENTRE, LIBRARY AVENUE BAILRIGG, LANCASTER, LANCASHIRE LA1 4AP                                              Prepared by Ian J Winfield BSc, PhD, MIFM, CEnv Janice M Fletcher BSc J Ben James     Project Leader:  Ian J Winfield Contract Start Date:  1 August 2007 Report Date:  31 January 2008 Report To:  Environment Agency (North West Region) and Scottish Natural Heritage CEH Project No:  C03462 CEH Report Ref No:  LA/C03462/1  This is an unpublished report and should not be cited without permission.     ASSESSMENT OF THE VENDACE POPULATION OF BASSENTHWAITE LAKE INCLUDING OBSERVATIONS ON VENDACE SPAWNING GROUNDS  PROGRESS REPORT FOR PERIOD AUGUST 2007 TO JANUARY 2008                                         INTELLECTUAL PROPERTY RIGHTS  CONFIDENTIALITY STATEMENT  'In accordance with our normal practice, this report is for the use only of the party to whom it is addressed, and no responsibility is accepted to any third party for the whole or any part of its contents.  Neither the whole nor any part of this report or any reference thereto may be included in any published document, circular or statement, nor published or referred to in any way without our written approval of the form and context in which it may appear' CONTENTS          PAGE  Executive summary          1  Chapter 1 Introduction         3   1.1 Background        3   1.2 Objectives        4  Chapter  2 Underwater observations on vendace spawning grounds   5  Chapter  3 Customised gill netting in deep water     7  Chapter  4 Ecological conditions of vendace spawning grounds    8  Chapter  5 Research planned for next reporting period     9   6.1 Underwater observations on vendace spawning grounds  9   6.2 Customised gill netting in deep water    9   6.3 Ecological conditions of vendace spawning grounds   10    Acknowledgements          11  References           12  Figures           14     1 EXECUTIVE SUMMARY  1.  Previous studies and a current monitoring programme have shown that the status of the vendace (Coregonus albula) in Bassenthwaite Lake in north-west England has now been poor for at least two decades.  Furthermore, a survey gill-netting component of the monitoring programme has not recorded any biological specimens of vendace since 2000, although four individuals were recorded in 2001 during broodstock collection for a translocation programme.  Such survey gill netting is undertaken at a relatively low level of effort because of its destructive nature and the fact that it catches appreciable numbers of several other fish species.  Given this situation, it is now highly desirable to use other means to acquire a robust assessment of the continued presence or otherwise of the vendace in Bassenthwaite Lake  2.  The primary objective of the present project was to attempt to produce unequivocal evidence of the continued presence of vendace in Bassenthwaite Lake by the use of underwater video and high-frequency hydroacoustics observations on a known vendace spawning ground, and by the deployment of a high sampling effort of customised gill nets in deep water.  In addition, a secondary objective was to develop bottom-typing and macrophyte analyses of hydroacoustic recordings recently made on vendace spawning grounds in order to improve the assessment of their ecological conditions.  3.  An underwater video system with colour and infra-red cameras was deployed on a known vendace spawning ground near Beck Wythop in Bassenthwaite Lake on the evenings of 22 November, 6 December and 12 December 2007, and for comparative purposes on a known vendace spawning ground near Calf Close Bay in Derwent Water on 11 December 2007.  No   2 vendace were observed at either site, although large numbers of ruffe were observed at Bassenthwaite Lake.  In addition, a high-frequency hydroacoustics DIDSON system was also deployed during the underwater video observations of 6 December at Bassenthwaite Lake.  Although recordings have yet to be reviewed in detail, it is clear that this system also did not record any vendace.  Thus, both types of observations failed to produce any sightings of vendace in Bassenthwaite Lake.  Although disappointing, this finding does not itself constitute definitive evidence of the local extinction of vendace.  4.  Other than arranging the construction and delivery of customised gill nets, no activity was undertaken in this area during the present reporting period.  5.  Hydroacoustics recordings made previously on vendace spawning grounds in Bassenthwaite Lake and Derwent Water were explored with the developers of the analytical softwares VBT and EcoSAV, which are appropriate for bottom typing and macrophyte mapping, respectively.  It appears that the collection of further ground-truthing data is likely to be necessary to complete the bottom typing of the recorded survey data, which may not be possible within the resources of the present project.  Discussions and data explorations in this general field were also held with the developers of the analytical software Sonar5-Pro  6.  Further work is planned for the remainder of the present project to continue examination and analyses of the above underwater video and high-frequency hydroacoustics recordings, to undertake customised gill netting including an examination of ruffe diet for vendace eggs, and to continue bottom-typing and macrophyte analyses of the previously collected hydroacoustic recordings as far as possible within the resources of the present project.   3 CHAPTER 1  INTRODUCTION  1.1  Background  Previous studies (Mubamba, 1989;  Winfield et al., 1994) and a current monitoring programme (Winfield et al., 2007a) have shown that the status of the vendace (Coregonus albula) in Bassenthwaite Lake in north-west England has now been poor for at least two decades.  Furthermore, a survey gill-netting component of the monitoring programme of Winfield et al. (2007a) has not recorded any biological specimens of vendace since 2000, although four individuals were recorded in 2001 during broodstock collection for a translocation programme.  Although such survey gill netting is undertaken at a relatively low level of effort because of its destructive nature and the fact that it catches appreciable numbers of several other fish species, the recent persistent absence of vendace suggests that this species may now be locally extinct.  The vendace population of Bassenthwaite Lake faces a number of environmental threats including species introductions, eutrophication, climate change and sedimentation on its spawning grounds (Winfield et al., 2004), but the latter problem currently appears to be the most severe.  Extensive surveys of known and potential vendace spawning grounds in Bassenthwaite Lake and nearby Derwent Water, the only other U.K. lake with a surviving native vendace population, have observed widespread deposits of fine sediments in the former but not latter lake (Winfield et al., 1998;  Winfield et al., 2007b).  In anticipation of the potential consequences of the deteriorating environmental conditions in Bassenthwaite Lake, a refuge population of vendace originating from this water body has been established in   4 Loch Skeen (or Skene) in south-west Scotland (Lyle et al., 1999;  Maitland et al., 2003) and is currently being assessed (Winfield et al., 2007c).  This new population forms a potential source of vendace for future restocking into a restored Bassenthwaite Lake.  Given the above situation, it is now highly desirable to acquire a more robust assessment of the continued presence or otherwise of the vendace in Bassenthwaite Lake.  Although the vendace monitoring programme described above continues, its biological sampling effort cannot be feasibly increased significantly due to its by-catch of other fish species.  As a result, it is unlikely to record any vendace unless the local population increases significantly in abundance.  At extremely low population densities, alternative sampling approaches are required in order to detect vendace unequivocally.  Conversely, although it is impossible to prove a negative, if such techniques again fail to record vendace then this would add further weight to a hypothesis of local extinction.  1.2  Objectives  The primary objective of the present project was to attempt to produce unequivocal evidence of the continued presence of vendace in Bassenthwaite Lake by the use of underwater video and high-frequency hydroacoustics observations on a known vendace spawning ground, and by the deployment of a high sampling effort of customised gill nets in deep water.  In addition, a secondary objective was to develop bottom-typing and macrophyte analyses of hydroacoustic recordings recently made on vendace spawning grounds in order to improve the assessment of their ecological conditions using this rapidly developing technique.   5 CHAPTER 2  UNDERWATER OBSERVATIONS ON VENDACE SPAWNING GROUNDS   A SeaViewer Underwater Video System with colour and infra-red cameras and integral lights (SeaViewer Cameras, Inc., Tampa, U.S.A., www.seaviewer.com) mounted to a static platform and recording digitally to an ARCHOS 604 Portable Multimedia Player (ARCHOS, Igny, France, www.archos.com) was used as the primary method of underwater observation (Fig. 1).  This system was deployed on a known vendace spawning ground near Beck Wythop in Bassenthwaite Lake on the evenings of 22 November, 6 December and 12 December 2007, and for comparative purposes on a known vendace spawning ground near Calf Close Bay in Derwent Water on 11 December 2007.  No vendace were observed at either site, although large numbers of ruffe (Gymnocephalus cernuus) were observed at Bassenthwaite Lake (Fig. 2).  In addition, a high-frequency hydroacoustics DIDSON system (Sound Metrics Corp., Washington, U.S.A., www.soundmetrics.com (see Moursunda et al. (2003)) owned and operated by the Environment Agency was also deployed during the underwater video observations of 6 December at Bassenthwaite Lake.  Although recordings have yet to be reviewed in detail, it is clear that this system also did not record any vendace.  In summary, underwater video and high-frequency hydroacoustics observations over three evenings on a known vendace spawning ground in Bassenthwaite Lake failed to produce any sightings of this species.  Although disappointing, this finding does not itself constitute definitive evidence of the local extinction of vendace as evidenced by its failure to record   6 specimens in Derwent Water, where the population is known to persist (Winfield et al., 2007a).   7  CHAPTER 3  CUSTOMISED GILL NETTING IN DEEP WATER  Other than arranging the construction and delivery of the customised gill nets from a scientific supplier (Lundgrens Fiskredskap, Stockholm, Sweden, www.lundgrensfiske.com), no activity was undertaken in this area during the present reporting period.   8 CHAPTER 4  ECOLOGICAL CONDITIONS OF VENDACE SPAWNING GROUNDS  Hydroacoustics recordings made on vendace spawning grounds in Bassenthwaite Lake and Derwent Water during April 2007 by Winfield et al. (2007b) were explored during October 2007 with the developers (BioSonics Inc, Seattle, U.S.A., www.biosonicsinc.com) of the analytical softwares VBT and EcoSAV, which are appropriate for bottom typing and macrophyte mapping, respectively.  It appears that the collection of further ground-truthing data is likely to be necessary to complete the bottom typing of the recorded survey data, which may not be possible within the resources of the present project.  In addition, during December 2007 discussions and data explorations in this general field were also held with the developers (Lindem Data Acquisition, Oslo, Norway, www.fys.uio.no/~hbalk/sonar4_5) of the analytical software Sonar5-Pro.  Although this software was initially developed for the analysis of hydroacoustics data for fish, it now also contains a macrophyte analysis module and may be further developed in the near future for bottom-typing analyses of the kind required within the present study.   9 CHAPTER 5  RESEARCH PLANNED FOR NEXT REPORTING PERIOD  6.1  Underwater observations on vendace spawning grounds   Examination and analyses of underwater video and high-frequency hydroacoustics recordings made at Bassenthwaite Lake and Derwent Water during November and December 2007 will be completed.  6.2  Customised gill netting in deep water  Customised gill nets with a range of mesh sizes appropriate to adult vendace will be set at a series of deepwater sites in Bassenthwaite Lake at a sampling effort much greater than that of the current monitoring programme described by Winfield et al. (2007a).  By appropriate net location and the careful selection of a restricted range of mesh sizes, by-catches of other species such as brown trout (Salmo trutta), perch (Perca fluviatilis), pike (Esox lucius), roach (Rutilus rutilus) and ruffe will be minimised.  Netting will be continued through the project as resources and opportunities allow, but will be stopped if and when it has been established that a vendace population is still present in the lake.  Any such specimens will be photographed and basic biological features measured following Winfield et al. (op. cit.), together with the preservation of a fin clip for potential genetic examination.  Field work is currently planned to begin in the week of 11 February 2008.    10 In addition to the above direct search for vendace, evidence for their continued presence in the lake will also be sought by the examination of samples of ruffe taken during the same sampling for the presence of vendace eggs in their diet.  6.3  Ecological conditions of vendace spawning grounds  Bottom-typing and macrophyte analyses of the hydroacoustic recordings from Bassenthwaite Lake and Derwent Water will be continued as far as possible within the resources of the present project.   11 ACKNOWLEDGEMENTS  We thank Jon Hateley and Andy Gowans of the Environment Agency for their much appreciated deployment of a DIDSON system at Bassenthwaite Lake under extremely unpleasant weather conditions.  We are also grateful to Alex Lyle of ALP and Peter Maitland of the Fish Conservation Centre for their assistance during underwater video observations at Derwent Water.  Jim Dawson, Bob McClure and particularly Brian McFadden of BioSonics provided invaluable advice with respect to the present application of VBT bottom-typing software, while Helge Balk and Torfinn Lindem of Lindem Data Acquisition engaged in useful discussions concerning the potential application of Sonar5-Pro within this project.  This work was jointly funded by the Centre for Ecology & Hydrology, the Environment Agency and Scottish Natural Heritage.   12 REFERENCES  Lyle, A. A., Maitland, P. S. & Winfield, I. J.  (1999).  Re-introduction of vendace:  Phase II Extension.  Final Report.  Report to Scottish Natural Heritage.  ED/T11063y7/4.  11 pp.  Maitland, P. S., Lyle, A. A. & Winfield, I. J. (2003).  Survey of vendace in Daer Reservoir and Loch Skene.  Report by Fish Conservation Centre to English Nature (English Nature Contract No. EIT 34-01-006).  29 pp.  Moursunda, R. A., Carlson, T. J. & Peters, R. D.  (2003).  A fisheries application of a dual-frequency identification sonar acoustic camera.  ICES Journal of Marine Science 60, 678-683.  Mubamba, R.  (1989).  The ecology of the coregonid fishes in the English Lake District.  Unpublished Ph.D. Thesis. University of Wales.  Winfield, I. J., Fletcher, J. M. & Cubby, P. R. (1994).  Status of Rare Fish, Project Record Volume 1.  Report to National Rivers Authority.  WI/T11050m1/9.  244 pp.  Winfield, I. J., Fletcher, J. M. & Cubby, P. R. (1998).  Spawning beds of vendace in Bassenthwaite Lake and Derwentwater.  Final Report.  Report to English Nature.  WI/T11063f1/2.  22 pp.    13 Winfield, I. J., Fletcher, J. M. & James, J. B.  (2004).  Conservation ecology of the vendace (Coregonus albula) in Bassenthwaite Lake and Derwent Water, U.K.  Annales Zoologici Fennici 41, 155-164.  Winfield, I. J., Fletcher, J. M. & James, J, B.  (2007a).  The Urban Waste Water Treatment Directive:  Monitoring the vendace populations of Bassenthwaite Lake and Derwent Water, 2006.  Report to Environment Agency, North West Region.  LA/C01752/19.  46 pp.  Winfield, I. J., Fletcher, J. M. & James, J. B.  (2007b).  Further development of an artificial spawning substrate system for vendace.  Final Report.  Report to Environment Agency, North West Region.  LA/C03215/3.  72 pp.  Winfield, I. J., Fletcher, J. M., & Lyle, A. A. (2007c).  Assessment of the vendace refuge population of Loch Skeen.  Draft Final Report.  Report to Scottish Natural Heritage.  LA/C02539/2.  20 pp.    14 Fig. 1.  The SeaViewer Underwater Video System with colour and infra-red cameras and integral lights mounted to a static platform as used as the primary method of underwater observation on vendace spawning grounds in Bassenthwaite Lake and Derwent Water.     15  Fig. 2.  Representative images taken from the underwater video recording on the vendace spawning ground near Beck Wythop in Bassenthwaite Lake on 22 November 2007 showing a ruffe approaching (upper image, visible as a pair of bright eyes) and then turning to the left (lower image, visible as a single bright eye and side of body).  Note that time and date are given as Greenwich Mean Time and month-day-year format, respectively.      16  

Assessment of the vendace population of Bassenthwaite Lake including observations on vendace spawning grounds.  Progress Report for Period August 2007 to January 2008

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Assessment of the vendace population of Bassenthwaite Lake including observations on vendace spawning grounds. Progress Report for Period August 2007 to January 2008

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