Title

Spatial distribution of the crepidula (Crepidula fornicata) in the bay of Brest between 2013 and 2018

Date (Publication)

2023-02-28

Date (Creation)

2023-02-13

Date (Revision)

2023-07-17

Citation identifier

https://sextant.ifremer.fr/geonetwork/276dab32-7db7-420c-acd1-d61a56ec378d

Abstract

Monitoring the spatial distribution of crepidula (Crepidula fornicata) between 2013 and 2018 using underwater video and grab samples in the Bay of Brest

Credit

Ifremer, DYNECO, F-29280 Plouzané, France / REBENT, EC2CO-DRIL "Evocrep", H2020 JERICO-Next projects

Point of contact

Organisation name	Individual name	Electronic mail address	Role
IFREMER	Carlier Antoine	Antoine.Carlier@ifremer.fr	Author
IFREMER	Androuin Thibault		Author
IFREMER	Caisey Xavier		Author
IFREMER	Cordier Celine	Celine.Cordier@ifremer.fr	Author
IFREMER	Gaffet Jean-Dominique		Author
IFREMER	Perier Vincent	Vincent.Perier@ifremer.fr	Author
IUEM	Grall Jacques	jacques.grall@univ-brest.fr	Author
IFREMER	Carlier Antoine	Antoine.Carlier@ifremer.fr	Local service desk
Ifremer, DYNECO, F‐29280 Plouzané, France			Publisher

Thèmes Sextant

• /Biological Environment/Habitats

GEMET - INSPIRE themes, version 1.0

• Habitats and biotopes

Use limitation

CC-BY-NC (Creative Commons - Attribution, No commercial usage)

Access constraints

Other restrictions

Use constraints

Copyright

Other legal constraints

Obligation to quote:

Carlier Antoine, Androuin Thibault, Caisey Xavier, Cordier Céline, Gaffet Jean-Dominique, Perier Vincent, Grall Jacques (2023). Spatial distribution of the crepidula (Crepidula fornicata) in the bay of Brest between 2013 and 2018. Ifremer, DYNECO, F‐29280 Plouzané, France. https://doi.org/10.12770/276dab32-7db7-420c-acd1-d61a56ec378d

Code

https://doi.org/10.17600/13070040

Association Type

Cross reference

Initiative Type

Platform

Code

https://doi.org/10.17600/13150010

Association Type

Cross reference

Initiative Type

Platform

Code

https://doi.org/10.17600/18000413

Association Type

Cross reference

Initiative Type

Platform

Code

https://doi.org/10.17600/16007300

Association Type

Cross reference

Initiative Type

Platform

Code

https://doi.org/10.17600/13120090

Association Type

Cross reference

Initiative Type

Platform

Code

https://doi.org/10.17600/18003092

Association Type

Cross reference

Initiative Type

Platform

Spatial representation type

Vector

Denominator

25000

Language

Français

Character set

UTF8

Topic category

• Oceans

Begin date

2013-03-01

End date

2018-04-25

Unique resource identifier

EPSG:2154

Geometric object type

Complex

Distribution format

Name	Version

OnLine resource

Protocol	Linkage	Name
OGC:WMS	https://sextant.ifremer.fr/services/wms/dyneco	RDB_crepidules_stations_2013_2018

OnLine resource

Protocol	Linkage	Name
OGC:WMS	https://sextant.ifremer.fr/services/wms/dyneco	RDB_crepidules_contours_2013_2018

OnLine resource

Protocol	Linkage	Name
DOI	https://doi.org/10.12770/276dab32-7db7-420c-acd1-d61a56ec378d	Digital Object Identifier (DOI)

Hierarchy level

Dataset

Statement

The spatial distribution of the crepidula (Crepidula fornicata) in the bay of Brest was studied as part of the national EC2CO-DRIL project (2013-2015) and the European JERICO-Next project (2015-2019). The aim was to draw up an inventory of the ecological status of the population of this invasive gastropod over the period 2013-2018, after a 30-year phase of proliferation that led to a very high biomass spread over half the surface area of the bay. As this species is gregarious and considered to be an "ingenious" species, it strongly structured the benthic communities and habitats during its expansion in the 1990s, forming very extensive shoals with several thousand individuals per square metre in places. Following several signals of decline recorded in the early 2000s, the aim was to examine the evolution of this habitat in terms of geographical distribution, vitality, density and biomass. Thanks to several campaigns of quantitative sampling, sonar imagery and underwater imagery, carried out using a suspended video frame (2013) and a towed video device (2016 and 2018), the decline of the crepidula has been clearly demonstrated throughout the southern part of the bay of Brest.

The data is separated into 2 distinct layers:

- The "stations" layer groups together all the direct observations (grab samples and photo-videos) and their analysis results (presence, densities, biomass).

Grab samples (Smith; 0.1 m²) were sieved through a 2 mm mesh and yielded quantitative data on densities (in number of individuals/m²) and biomass (in g of fresh weight, with shell/m²).

Deployment of the suspended video camera and the towed photo-video device provided qualitative data (presence/absence; vitality, living/dead) and semi-quantitative data (% cover on the seabed; number of chains of living individuals visible on the seabed). The data on % cover on the seabed was determined according to 5 classes of cover (0 % in the absence of crepidulids; 1 to 25 % of the image surface; 26 to 50 %; 51 to 75 %; 76 to 100 %).

With the suspended video frame, the surface area filmed when the frame is laid flat on the bottom is 0.05 m². At each station, around twenty video captures were recorded when the frame was placed on the bottom, representing a total of almost 1 m². Coverage classes are estimated independently for each capture, then averaged over the whole station.

With the towed video camera, the area photographed vertically from the camera was 0.29 m², and a photo was recorded every 10 seconds along the entire transect. As with the suspended video camera, the coverage classes are estimated independently for each photo. The level of vitality of the crepidulas (proportion of living individuals among the visible crepidulas) is estimated on each photo according to 5 classes from 0 to 4 (0: all the visible crepidulas are dead; 2: half the visible crepidulas are alive; 4: all the visible crepidulas are alive).

- The "contours" layer shows the location and limits of the main banks of crepidula (live or dead) present in the bay of Brest, with a coverage of more than 50%. The contours were drawn manually using sonar data from the REB-RAD-H-2013 campaign (https://doi.org/10.17600/13120090) and observation data. The contours of the banks partly follow the sedimentary limits of the map by Gregoire et al (2016)*.

* Gwendoline Gregoire, Axel Ehrhold, Pascal Le Roy, Gwenael Jouet & Thierry Garlan (2016) Modern morpho-sedimentological patterns in a tide-dominated estuary system: the Bay of Brest (west Britanny, France), Journal of Maps, 12:5, 1152-1159, DOI: 10.1080/17445647.2016.1139514

Description

Update on 13/07/2023: Data from the Pagure video towed vehicle added to the station layer

Feature catalogue citation

• Attributs pour les couche polygones - " Distribution spatiale de la crépidule (Crepidula fornicata) en rade de Brest entre 2013 et 2018 "

Feature catalogue citation

• Attributs pour les couche points - " Distribution spatiale de la crépidule (Crepidula fornicata) en rade de Brest entre 2013 et 2018 "

Metadata

File identifier

276dab32-7db7-420c-acd1-d61a56ec378d

Metadata language

Français

Other language

Language	Character encoding
English	UTF8

Character set

UTF8

Hierarchy level

Dataset

Date stamp

2023-10-26T12:57:15.518Z

Metadata standard name

ISO 19115:2003/19139 - SEXTANT

Metadata standard version

1.0

Metadata author

Organisation name	Individual name	Electronic mail address	Role
IFREMER	Cordier Celine	Celine.Cordier@ifremer.fr	Local service desk