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InterReg IVa-2 seas
Mnemiopsis Ecology and Monitoring:
Observation of an invasive comb-jelly
MEMO join survey
14 – 24th October 2012
Partner Leg 1 Leg 2
ILVO 1 1
IFREMER 3 1
CEFAS 1 1
ULCO-LOG - 1
Deltares - 1
MEMO join survey: sampling
Sampling Area Number of station
FR coast 15
BE coast 4
Scheldt estuary 15
NL coast 8
Thames 6
UK coast 8
Total 56
Data collected at each station
- CTD profils (T°C, S, Fluo., Turb., PAR)
- Phytoplankton Abundance (CEFAS)
- Chla, SPM, Nutrients (ULCO-LOG)
- Mesozooplankton abundance (IFREMER)
- Jelly abundance & size
- M. leidyi DNA analyses (ILVO)
- SI analyses on jelly and other stuff (ILVO)
- Ichthyoplankton abundance (IFREMER)
MEMO join survey:
What is analysed and available yet?
- CTD profils (T°C, S, Fluo., Turb., PAR): average calculated every 0.5 m
- Phytoplankton Abundance (CEFAS): done
- Chla, SM, Nutrients (ULCO-LOG): Chla , SPM in progress , Nutrients
- Mesozooplankton abundance (IFREMER): done (need to validate copepods
from leg2)
- Jelly abundance & size done (except for some hydromedusa from leg 1)
- M. leidyi DNA analyses (ILVO) done
- SI analyses on jelly and other stuff (ILVO) done
- Ichtyoplankton abundance (IFREMER) not yet
MEMO join survey: Access database
All the data from the
cruise have been
registered in an access
database that is
available on the MEMO
sharepoint
MEMO_survey2012
MEMO join survey: objectives
Map the distribution of abundances to look at spatial
coincidences between Mnemiopsis and other zooplankton
key groups
Identification of environmental typologies in the study area
Characterise these typologies according to plankton
assemblages (phytoplankton, zooplankton and gelatinous
plankton)
MEMO join survey: objectives
Station coordinates on the two first axes
of the PCA
Environmental parameters
PCA
Mapping
Identified objects
F1 + F2 (ind.m-3)
HAC
(5 classes)
Cluster characterisation
MEMO join survey: PCA result
Axe 1
(53,59 %)
Axe 2
(27,35 %)
Axe 1
(53,59 %)
Axe 2
(27,35 %)
Température (71 %)
Salinité (51 %) Chlorophylle a (73 %)
Phéopigments (83 %)
MES (81 %)
MEMO join survey: HAC result
Classe 1
Classe 2
Classe 3
Classe 4
Classe 5
MEMO join survey:
Environmental typologies
Chlorophyll a -
Pheopigments -
SPM -
Temperature -
Salinity -
Chlorophyll a +
Pheopigments +
SPM +
Temperature
Salinity
Chlorophyll a +
Pheopigments +
SPM +
Temperature -
Salinity -
Chlorophyll a -
Pheopigments -
SPM -
Temperature +
Salinity +
Chlorophyll a
Pheopigments
SPM
Temperature +
Salinity +
MEMO join survey:
Cluster 1: zooplankton characterisation
• High abundance of Mnemiopsis leidyi
• Presence of Beroe gracilis
• Very few abundance of copepods
• Absence of chaetognathes et peracarids
• High abundance of meroplankton and of peracarids
MEMO join survey:
Cluster 2: zooplankton characterisation
• High abundance of meroplankton larvae
MEMO join survey:
Cluster 3: zooplankton characterisation
MEMO join survey:
Cluster 4: zooplankton characterisation
High abundance of chaetognathes
Absence of M. leidyi and B. gracilis
MEMO join survey:
Cluster 5: zooplankton characterisation
• High abundances of copepods
• Absence of M. leidyi and B. gracilis
Some conclusions and comments on:
Gelatinous plankton
• Mnemiopsis leidyi : eurytherm and euryhalin but not distributed in the whole area, only in the most shallow region (class 1) preference for low hydrodynamism?
• Presence of predators:
– Beroe gracilis : predates on sea gooseberry, probably also on M. leidyi (small size)
– Scyphomedusa (Chrysaora hysocella and Aurelia aurita) : too few individuals to impact/control M. leidyi abundances
– Pleurobrachia pileus : distributed in the whole area, but especially abundant in the mouth of Thames What are the differences between life cycle of P. pileus and M. leidyi ?
Some conclusions and comments on:
Mnemiopsis impact on Mesozooplankton
• Mnemiopsis leidyi : high predation on copepods explain
low abundance of copepods, but also absence of
chaetognaths that eat copepods (but they may also be
eaten by Mnemiopsis)
• Peracarids : predation of M. leidyi on peracarids but also
low concentration of chlorophyll pigments and SPM
Chlorophylle a -
Phéopigments -
MES -
Some conclusions and comments on:
Mnemiopsis impact on Mesozooplankton
• Meroplankton : high concentration of chlorophyll pigments
and SPM
Chlorophylle a +
Phéopigments +
MES +
Some conclusions and comments on:
Mnemiopsis impact on Mesozooplankton
• Mnemiopsis leidyi absente from English and French
coasts (except in Dunkerque harbour) seems to
prefer shallow areas as Grevelingen and Oosterschelde
estuary oriental BUT possibility of estention through
adjacent regions
• Strong impact on zooplankton communities (especially
copepods) impact on small pelagic fishes
(competition) impact on fisheries activities
Some conclusions and comments on:
Mnemiopsis impacts
• Improved description of environmental typologies including
phytoplankton identification made by CEFAS on MEMO cruise
• Distinguish among copepod genus to get more information
on M. leidyi impact on diversity and on potential prey-
predation relationship (match/mismatch)
• Applied these on others seasons MEMO 2 ???
Some percpectives
21
Thank you! Merci! Bedankt!
Elvire Antajan, Morgane Travers-Trolet, Christophe Loots & Sandrine Vaz
Zooplankton Taxonomy and Ecology Cluster
MEMO meeting – 3-5th April 2013