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