# Chondrichthyans Distribution Atlas within North-Eastern Atlantic and French Mediterranean waters

Amaëlle Bisch, Pauline Stephan, Thomas Barreau, Caroline Bousquet, Eric Durieux, Sophie A.M.Elliott, Sébastien Mayot, Matthieu Lapinski, Alexandra Rohr, Eric Stephan, et al.

► To cite this version:

Amaëlle Bisch, Pauline Stephan, Thomas Barreau, Caroline Bousquet, Eric Durieux, et al. Chondrichthyans Distribution Atlas within North-Eastern Atlantic and French Mediterranean waters. European Elasmobranch Association Conference, Oct 2024, Thessalokini, Greece. hal-04773055

HAL Id: hal-04773055

https://hal.science/hal-04773055v1

Submitted on 8 Nov 2024

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# Chondrichthyans Distribution Atlas

## within North-Eastern Atlantic and French Mediterranean waters

Bisch A.¹, Stephan P.¹, Barreau T.², Bousquet C.³, Durieux E.³, Elliott S.⁴, Mayot S.², Lapinski M.⁵, Rohr A.⁶, Stephan E.⁶, Bouet M.⁷, Santoni M-C.⁷, Dorémus G.⁸, Laliche C.⁵, Paillon C.², Coulon N.², Labourgade P.⁹, Carpentier A.¹⁰, Delesalle M.¹, Acou A.¹

¹UAR OFB-MNHN PatriNat; ²MNHN; ³Univ. de Corse Pasquale Paoli; ⁴Game & Wildlife Conservation Trust; ⁵Association AILERONS; ⁶Association pour l'étude et la conservation des sélaciens (APECS); ⁷Office de l'Environnement de la Corse; ⁸Observatoire Pelagis - La Rochelle Université / CNRS; ⁹MNHN et FEM; ¹⁰Univ. de Rennes I

## INTRODUCTION

In the context of Marine Strategy Framework Directive (MSFD), accurate and up-to-date distribution maps of the 106 chondrichthyans (40 batoids, 59 sharks and 7 chimaeras) present in French metropolitan marine waters is required. For that, a database from fisheries-dependent and -independent data was collated to produce a chondrichthyan distribution atlas.

## METHODS

### Study area & period

<figure><img src="image_4.png" /><figcaption>Data pooled from 2003 to 2021</figcaption></figure>

### Data sources

<table><thead><tr><th>Fishery- dependent data</th><th>Scientific surveys</th><th>Citizen science</th></tr></thead><tbody><tr><td>&gt; 105 000 fishing operations (fo) and 3800 landings</td><td>64 000 fo &gt;11 000 (aerial, boat & submarine) transects</td><td>&gt; 3 300 observations</td></tr><tr><td>Presence-absence, length & depth at capture</td><td></td><td>presence-only</td></tr></tbody></table>

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ICES
CIEM

International Council for the Exploration of the Sea
Conseil International pour l'Exploration de la Mer

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Ifremer

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STARESO

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APEC'S
Association Pour l'Exploration et la Conservation des Sélaciens

BioObs

Base pour l'Inventaire des Observations Subaquatiques

<figure><img src="image_18.png" /></figure>

ELASMED

OBSERVATOIRE CIToyEN REQUIS,
RAIES ET CHIMÉRES DE MÉDITERRAINE FRANÇAISE

### Certainty of Data Occurrence Category (CODOC)

* To limit potential misidentification issue

Assessment by known distribution area ¹,³,⁴

<figure><img src="image_19.png" /></figure>

### Data sources:

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DATRAS
MEDITS

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ObsMer
APEC'S

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PELAGIS
BioObs

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Acoustic surveys
Med-CorSeaCan
ELASMED

References: ¹ Ebert & Dando (2022); ² Weigman (2016); ³ UICN (2023);

⁴ Last *et al.* (2016)

## RESULTS : 106 species fact sheets including:

### A general overview

<figure><img src="image_24.png" /></figure>

<table><thead><tr><th>Area</th><th>Status</th><th>Year</th></tr></thead><tbody><tr><td>France</td><td>DD</td><td>2013</td></tr><tr><td>Mediterranean</td><td>NT</td><td>2016</td></tr><tr><td>Europe</td><td>NT</td><td>2015</td></tr><tr><td>Global</td><td>EN</td><td>2003</td></tr></tbody></table>

Not included in any convention

with a short summary of habitat and biology

Occurrence maps broken down by 3 regions: NE Atlantic, Gulf of Lion (not displayed) and Corsica (not displayed)

### Species-specific catchability information by region

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### Scientific & on-board observer surveys

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### EOS (landings) surveys

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### Citizen science programs

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## CONCLUSION

* Unprecedented database of chondrichthyan distribution with 175 702 occurrences.

* The CODOC method helped provide important information on misidentified species (e.g., *Mustelus mustelus*, *Galeus murinus*).

* Data paper coming soon

* Modelling approach is in progress to produce robust distribution map (see Bisch *et al.* oral presentation).

HAL Open
Science id :

mnhn-04475562

or

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