routine acoustic data as new tools for a 3d vision of the ... · arnaud bertrand, mariano...

Routine acoustic data as new tools for a 3D vision of the abiotic and

biotic components of marine ecosystem and their interactions

First International Workshop of the SPRFMO Scientific Committee Task Group on Fishing Vessels

as Scientific Platforms

Arnaud Bertrand, Mariano Gutiérrez, Salvador Peraltilla, Michael Ballón, Ramiro Castillo, Alexis

Chaigneau, Ronan Fablet, Daniel Grados, Jérémie Habasque, Erwan Josse, Zayda Quiroz, Gildas

Roudaut, Gary Vargas, Francois Gerlotto

Universidad Nacional

Federico Villarreal

CardúmenesDe jurel

Zooplancton

Capa deeufausidos

Capa devinciguerriaCapa de

mictofidos

Capa demicronecton

Pota

Línea de superficie

ZMO-termoclina

Tiempo, GPS

Zona epipelágica

Profundidad

Ondas internas

Gutiérrez 2014

Digital echograms: the ecosystem reflected in sound

DePol-Holz et al. (2007)

1- Context: OMZ

• Global expansion of Oxygen Minimum Zones (OMZ) (e.g. Stramma et al., 2008)

• The Humboldt Current system presents a very intense and shallow OMZ

• Acoustic methods help understanding dynamics of ecosystem at diferent scales.

• Also to resolve and study physical processes our of reach to physical that use classic

methods (CTD, gliders)

Anchovy schools distributed after the layered aggregation of euphaussiids

Same place a couple of hours later, anchovy abandoned the layer (feeding.behavior)

1- Context: the high value of the opportunity of using fishing vessels

Gutiérrez et al in prep.

Echogram recorded on July 1th 2008 (at 09°35’S, 079°08’W) by a fishing vessel near

Casma, northern Peru. Dense anchovy schools lay distributed along the sea floor at more

than 100 m depth during a Kelvin wave propagation. Under “normal” conditions anchovy

dies not distribute deeper than 40 m.

1- Context: kelvin wave forcing detected by fishing vessels

A B

C D

Gutiérrez 2014

So, let’s change the way we “see” sound…

Sv Threshold = -65 dB Sv Threshold = -90 dB

Gutiérrez et al in prep.

(Bertrand et al., 2008, PinO)

1- Context: For fish and plankton, oxygen does matter

• In some cases: almost no room for fish (<10 m), anchoveta

seems to manage.

• It is not the case for sardine (and jack mackerel): oxygen is a

fundamental property regulating its population (Bertrand et

al., 2011 PLoS ONE)

• Classic oxygen measurements don’t resolve the

submesoscale

De

pth

(m

)

OMZ

DO (mL/L)

Ballón et al. (2011, PinO)

2- Listening to the oxycline depth

• Proxy of physical structuring of physical structuring

2- Listening to the oxycline

• Where the echoes stop, life stops, and here lies the oxycline...

9

OMZ?

Ep

ipela

gic

layer

Yes ! (Bertrand et al., 2010 PLoS ONE)

CTDO

track

VEEC

2- Listening to the oxycline

2005 2005

Niskin Acoustics

1 data each station 1 data each second

Acoustics to map the lower oxycline depth

Bertrand et al. (2004b)Swartzman et al. (2008)

Water mass distribution

Horizontal

Volume

82ºW 80ºW 78ºW 76ºW 74ºW 72ºW 70ºW

18ºS

16ºS

14ºS

12ºS

10ºS

8ºS

6ºS

4ºS

Continental shelf edge

Depth of the base of the oxycline

Depth (m)

140

130

120

110

100

90

80

70

60

50

40

30

20

10

Vertical

Bertrand et al. (2010)

3- Towards a 3D habitat


Bertrand et al. (2010, PLoS ONE)

Peru

3- Towards a 3D habitat Multiple scale study

8018

6

7816

14

12

10

872

74

76

Latitude (ºS)

Longitude (ºW

)

0

150

100

50

Depth

(m

)

Paita

PiscoCallao

Chimbote

Log(F

ish N

AS

C+

1)

18

Chlorophyll

Bertrand et al. (2010, PLoS ONE)

Peru

Resources Competitors

4- 3D multi-components habitat

Predators

Oxygen minimum zone

Key missing parameter: the prey!

4- Filling the volume of habitat

Zoopk. Squat lobster

Epipelagic

layer

Algorithm

Combining

ΔMVBS

and

+MVBS

38 kHz120 kHz

Zoopk + squat lobster

Fish ‘others'

OMZ OMZ

OMZ

OMZ OMZ

OMZ

OMZ

Epipelagic

layer

Epipelagic

layer

Ballón et al. (2011, PinO)

Multiple components approach

Upper OMZ

depth

Epipelagic

Fish

Epipelagic

Macrozoopk.

Peru

2005 Day


• Multiple components approach




Upper OMZ

depth

Epipelagic

+ migrant Fish

Epipelagic +

migrant

Macrozoopk.

Peru

2005 Night


Upper OMZ

depth

Epipelagic

Fish

Epipelagic

Macrozoopk.

Peru

2008 Day




Upper OMZ

depth

Epipelagic

+ migrant

Fish

Epipelagic +

migrant

Macrozoopk.

Peru

2008 Night



Zooplankton

Fish

Oxycline

Sea

surface

Mesoscale

(10s km)

Sub-mesoscale

(100s m to kms)

Ph

ys

ica

l

forc

ing

Bio

log

ica

l

forc

ing

+

+

+

+

+

+

_

_

_

_

_

_

5. Oxycline depth as a proxy of physical structuring

><>

<

Anticyclonic eddy

Downwelling

Convergence

Downwelling

Convergence

Cyclonic eddy

Upwelling

DivergenceUpwelling

Divergence

Significant

asynchrony

Significant

synchrony

UpwellingDownwelling

Zoopk. patchZoopk. minimum

5- Oxycline and bio-physical structuring, meso and submeso scales

• Oxycline depth: proxy of physical forcing

Grados et al. (2012, CJFAS)

6- Fishers as observers (Echopesca)

Peruvian fleet data analysis: first results

TASA raw files

Echosounder : ES60

Frequency : 120 kHz

LEGEND:AnchovyJack mackerelSquat lobsterVincigerria

Study zone (cruising phase)

6- Fishers as observers

Original echogram (21h32 – 22h03)

Noise removed (IFREMER algorithm)


Filtered echogram (21h32 – 22h03)


Filtered echogram (21h32 – 22h03) and oxycline depth

Oxycline depth

Oxycline depth and anchovy shoals (21h32 – 22h03)

Oxycline depth

‘Prey field’: macrozooplankton and other stuff…

School mask and threshold at -75db

Convergence

DwDivergence

Uw

6- Fishers as observers of oxycline and biophys.struct. of meso and subm

Evidence of two scales of aggregation (meso and submeso)


High coverage!

3 months of

data: January-

March 2011

Conclusion, Multiple components approach

Application:

• routine historical data

• fishing vessel data

High resolution data on:

• fish, macrozooplankton and oxycline depth

• Monitoring habitat characteristics, studying the

spatiotemporal variability, impact of habitat

compression, etc.

• OMZ upper depth (i) limits the vertical range of oxygenated

habitat, and (ii) is a proxy of physical structuring (eddies...)

shape macrozoopk. Distribution

• Forage fish distribution depends directly on macrozoopk.

distribution step forward for the implementation of the

ecosystem approach to fisheries

Fis

h

Macrozoopk. biomass

Oceanographic and Fishery Monitoring in

selected areas ( MOPAS): ideal alternative

to complement and support conventional

large scale survey

• Zero cost

• Quantitative monitoring of fish and

zooplankton

• Measure the habitat volumen in selected

áreas and changes in water masses.

• Fill the gaps between large scale surveys

• Generate indexes by regions (MOZ etc).

Progresses:

• Echoview license

• Calibration protocol available

• Fish and zooplankton protocol available

• Beta version of Echopesca

Challenges:

• Fragmentation of data, assemblage of

analysis

• “hands in” approach (university coop.)

• IMARPE’s commitment.

routine acoustic data as new tools for a 3d vision of the ... · arnaud bertrand, mariano...

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