Multifrequency Acoustics for the Classification of Pelagic Organisms. Ian H. McQuinn Institute Maurice Lamontagne, DFO Mont-Joli, Quebec, Canada

Transcription

1 Multifrequency Acoustics for the Classification of Pelagic Organisms Ian H. McQuinn Institute Maurice Lamontagne, DFO Mont-Joli, Quebec, Canada

2 Acknowledgements Acoustics Maxime Dion Nancy Otis Patrick Ouellet Jean-Pierre Allaire Nadia Ménard Marine Mammals Jean-François Gosselin Véronique Lesage Sophie Comtois Catherine Bajzak Richard Sears and his team from the MICS Robert Michaud and his team from the GREMM Valérie Harvey Thomas Doniol-Valcroze Samuel Turgeon Zooplankton Jean-François St. Pierre Stéphane Plourde Pierre Joly Chantale Méthot Caroline Lebel Félix St. Pierre Pierre Rivard Ships & Support Jacques Gagné Sylvain Chartrand Marie-Noëlle Bourassa Sylvain Cantin and his team Crew of the FG Creed Crew of the Coriolis II SHC

3 Introduction Effective sampling of the water column is a challenge Heterogeneous distribution of many organisms at very large and very small spatial scales Hydroacoustics sample the whole water column continuously at various spatial scales simultaneously Remote sensing Multifrequency classification to identify organisms applied to an increasing range of taxonomic groups and species Summarize recent applications of these techniques to large-, medium- and small-scale ecological studies, with special emphases on euphausiids and small pelagic fish in relation to whales foraging.

4 St. Lawrence Estuary Euphausiids dominate 3D "acoustic" biomass Two main species: M. norvegica, T. raschii Heterogeneous & dynamic distribution

5 The 4 th Dimension: behaviour Night Nautical Twilight Civil Twilight Day Depth (m) ~ E-07 5E E-07 1E E-07 2E-07 3E-07 4E Backscatter (sa) Backscatter (sa) Backscatter (sa) Backscatter (sa)

6 Euphausiids in the St. Lawrence Estuary Historically, the monitoring of zooplankton has been done by BIONESS surveys on a grid or on station transects In 2003, hydroacoustic data were collected (38, 120 & 200 khz)

7 Comparative Approach Euphausiid Density Acoustic Comparison of the hydroacoustic approach with the BIONESS catches (2003) BIONESS (without strobe)

8 Sampling Dense Patches Euphausiid density at Station K2 BIONESS: 9.7 g/m 2 Acoustic: g/m 2 BIONESS max. depth

9 Hydroacoustic Approach Hydroacoustic surveys are the principle means of evaluating pelagic fish biomass worldwide (Simmonds & MacLennan, 2005). A primary means of assessing krill biomass in Antarctic waters since the beginning of the 1980s (eg. Demer & Hewitt,, Lawson et al, ) and used in Canadian waters since the 1970s (Sameoto, Cochran et al.). The collection and analyses techniques of these data have greatly evolved in the intervening years. These data are used today to great advantage in ecosystem studies (Thomson & Allen, 2000; Sutor et al., 2005; Ward et al, 2005; ).

10 Multifrequency Approach Basic dual-frequency classification Frequency-response modelling Multifrequency classification of zooplankton and fish Ecological applications

11 db Difference 38 khz Difference in volume backscatter in db between 2 frequencies (38 & 120 khz) Differentiate between fluid and gaseous forms, e.g. crustacean zooplankton and fish (Holliday et al., Stanton et al.) Discrimination of Antarctic krill from other scatterers (Madureira et al., 1993) 120 khz

12 db Difference Classification

13 Species Groups Fish swimbaddered / nonswimbladdered (Korneliussen et al. 2004) Macrozooplankton krill (Kang et al. 2001, this paper) Mesozooplankton Calanus (Holliday et al. 1989) Invertebrates squid (Goss et al. 2001, Benoit-Bird et al. 2008, Jones et al. 2009) Lavery et al. 2007

14 Multifrequency Acoustics Krill Classification & Validation SDWBA physical model & frequency response 12 M. norvegica 12 T. raschii Frequency response re: 70kHz (db) T = (-1.0,5.0) L = (35.00,2.00) F = (1.00,0.05) T = (-1.0,5.0) L = (36.00,2.00) F = (1.00,0.05) T = (-1.0,5.0) L = (37.00,2.00) F = (1.00,0.05) T = (-1.0,5.0) L = (38.00,2.00) F = (1.00,0.05) T = (-1.0,5.0) L = (39.00,2.00) F = (1.00,0.05) JNC0904b010-1 JNC0904b010-2 Frequency response re: 70 khz (db) T = (-5.0,5.0) L = (20.00,2.00) F = (1.10,0.05) T = (-5.0,5.0) L = (21.00,2.00) F = (1.10,0.05) T = (-5.0,5.0) L = (22.00,2.00) F = (1.10,0.05) T = (-5.0,5.0) L = (23.00,2.00) F = (1.10,0.05) T = (-5.0,5.0) L = (24.00,2.00) F = (1.10,0.05) JNC0904b JNC0904b Frequency (Hz) Frequency (Hz)

15 Multifrequency Classification (MFC) Thysanoessa sp. Meganyctiphanes norvegica Ratio of Frequency Response

16 Validation of MFC BIONESS trajectory Net 1,2, etc Euphausiids sp.

17 Validation of MFC Acoustic classification BIONESS catch Thysanoessa sp Meganyctiphanes norvegica Net depth range (m) M. norvegica T. raschii T. inermis Krill density (g m -3 )

18 MFC of Fish Swimbladder / No Swimbladder

19 MFC of Fish Mackerel Herring

20 Medium-Scale Ecology Blue Whale Foraging on Krill in the St. Lawrence Estuary Hydroacoustic systematic stratified surveys 5 frequency acoustics: 38, 70, 120, 200, 333 khz Multifrequency analyses for forage species Plankton net sampling Species composition & biological parameters Marine mammal observations Distribution and foraging behavioural Spatial Analyses Predator/prey association

21 MF Classification M. norvegica All T. raschii SB Fish NSB Fish Marine Mammals

22 Whale-Krill Interactions Not the suspected species Northern krill more widely distributed Arctic krill more densely aggregated more well-defined patches higher in water column

23 Whale Foraging Behaviour Without blues With blues Arctic krill

24 Whale Foraging Behaviour Arctic krill "Feeding Frenzy" Not the highest abundances or densities

25 Small-Scale Ecology Focal Follows Head of the St. Lawrence Channel TDV Tag

26 Blue Whale Dive and Foraging Profile Head of the St. Lawrence Channel 1 hr 0 D - 25 Aug - Channel 0 Time 26 Aug 14:24 26 Aug 15:36 26 Aug 16:48 26 Aug 18:00 26 Aug 19: Tr Mn Mix Depth (m) Dive profile Lunges Depth (m) Depth (m) T. raschii Whale track Acoustic track

27 Blue Whale Surface Feeding T. raschii T. raschii "Surface swarms"

28 T. raschii Surface Swarms Swarm 1-40 m Swarm 2-40 m Swarm 3-40 m Swarm m Depth (m) Mean = 19.4 g m Arctic krill density (g m -3 ) Depth (m) Mean = 12.2 g m Arctic krill density (g m -3 ) Depth (m) Mean = 20.8 g m Arctic krill density (g m -3 ) Depth (m) Mean = 15.7 g m Arctic krill density (g m -3 ) Spawning

29 T. raschii Biological Parameters Spermatophore (no ind -1 ) Gonad maturity Gut fullness index Depth (m)

30 M. norvegica T. raschii Large-Scale Ecology 3D coupled bio-physical modeling

31 Finite-time Lyapunov Exponents Zones of Divergence and Convergence T. raschii August 2009 (Maps et al.)

32 Divergence zones present corridors & barriers to transport Correspondence with T. raschii aggregations

33 Summary Hydroacoustics effectively sample distributional heterogeneity at several spatial scales simultaneously continuous sampling non-intrusive many organisms from large to very small animal behaviour and species interactions Multifrequency classification effective for assessing the dominant pelagic fish and fluidform zooplankton organisms Provides the resolution required for validation of coupled bio-physical models transport processes patch formation Thank you