THE EFFECT OF CLIMATE THE EFFECT OF CLIMATE CHANGE ON SOFT CHANGE ON SOFT SEDIMENT BIVALVES & SEDIMENT BIVALVES & THEIR PATHOGENS THEIR PATHOGENS

Emer Morgan Supervisors : Drs Culloty & Ramsay

PROPOSED CHAPTERS

Reproduction of C. edule & Reservoir Species Parasites & BacteriaReservoir Species Environmental Effects on MortalitiesNeoplasia & the Presence of a VirusTrematode Genetics

WORK TO DATEWork To Date Work To Date

INTRODUCTION: REPRODUCTION INTRODUCTION: REPRODUCTION Separate Sexes

Sexual Maturity at 18 months

Previous published studies on reproduction in Ireland 1977/78

Milder winters linked to reduced recruitment

Mussel settlement adversely effected by rainfall

INTRODUCTION: PARASITES & INTRODUCTION: PARASITES & BACTERIA BACTERIA

16 species of digenean parasite

First & second intermediate host

Leads to impaired growth, parasitic castration, possibly death

Rickettsisosis

Fig 1: Range of Fig 1: Range of C. edule C. edule

Fig 2: Digenean Trematodes

INTRODUCTION: RESERVOIR INTRODUCTION: RESERVOIR SPECIES SPECIES

Reservoir hosts are significant because they maintain parasites in the absence of the primary host (Criscione et al., 2005)

Species that carry the pathogen/parasite

Not the preferred host

But keep the parasite/pathogen in the area when preferred host is unavailable

S. plana A. tenuis

M. balthica M. edulis

Fig 3: Reservoir Species

MATERIAL & METHODS MATERIAL & METHODS

Flaxfort Strand Bannow Bay

Fig 4: Sampling Methodology

MATERIALS & METHODS MATERIALS & METHODS Salinity

Oxygen Levels

Temperature

Fig 5: Environmental Data

MATERIALS & METHODS MATERIALS & METHODS

Fig 6: Laboratory Work

PRELIMINARY RESULTS: PRELIMINARY RESULTS: ENVIRONMENTAL DATA ENVIRONMENTAL DATA

Bannow Bay Temperature Range 9.48°C –27.97°CAverage 17.61°C Salinity Range - Flaxfort Strand 35-36‰

-Bannow Bay 16-36 ‰

Fig 7: Temperature Readout – Bannow Bay Channel

PRELIMINARY RESULTS: COCKLE PRELIMINARY RESULTS: COCKLE MORPHOMETRICS MORPHOMETRICS

Moribund cockles from Bannow Bay largestBuried cockles from Flaxfort Strand larger than those from Bannow BayWhole weight (g) of moribund cockles from Bannow Bay decreasing for last 3 months

Fig 8: Average Lengths mm

PRELIMINARY RESULTS: PRELIMINARY RESULTS: RESERVOIR SPECIES RESERVOIR SPECIES

MORPHOMETRICS MORPHOMETRICS Flaxfort Strand mussels greater in length & weight

S. plana greater in length in Bannow Bay

M. balthica & A. tenuis no consistent relationship between size & site

Fig 9: Mussel Average Lengths mm

PRELIMINARY RESULTS: COCKLE PRELIMINARY RESULTS: COCKLE SEX RATIOS & REPRODUCTION SEX RATIOS & REPRODUCTION

CI of moribund cockles less than buried cockles Fluctuations in CI may indicate spawningGreater number of females in Flaxfort Strand (20♂:26♀)Greater number of males in Bannow Bay (61♂:55♀)

Fig 10: Condition Indices

PRELIMINARY RESULTS: MUSSEL PRELIMINARY RESULTS: MUSSEL SEX RATIOS & REPRODUCTION SEX RATIOS & REPRODUCTION

oGreater CI in Bannow Bay

oFluctuations throughout the study

oMore females in Flaxfort Strand, more males in Bannow Bay

Fig 11: Mussel Condition Index

PRELIMINARY RESULTS: PRELIMINARY RESULTS: PARASITES & PATHOLOGICAL PARASITES & PATHOLOGICAL CONDITIONS CONDITIONS oMytilicola intestinalis identified in C. edule & M. edulis

oMetacercariae & Sporocysts in C. edule

oMetacercaria only in M. edulis

oNematopsis spp. oocysts in C. edule & M. edulis

Fig 12: Range of conditions identified

PRELIMINARY RESULTS: PRELIMINARY RESULTS: PARASITES & PATHOLOGICAL PARASITES & PATHOLOGICAL CONDITIONS CONDITIONS o Neoplasia in C. edule

o Prokaryote inclusions

Deposits in C. edule tissues

Markings on S. plana, M. balthica & A. tenuis tissues

Hydrobia ulvae inhabiting moribund cockles

Fig 13: Range of items seen in C. edule

PRELIMINARY DISCUSSION PRELIMINARY DISCUSSION

Variation between sites

Moribund cockles largest c.f. previous Flaxfort Strand study

Decrease in moribund cockles whole weights

Abiotic Biotic

•Salinity range •More disturbed •Less exposed

•Size differences•Time of spawning •Infection levels

PRELIMINARY DISCUSSION PRELIMINARY DISCUSSION

CI of buried cockles greater than moribund

CI of moribund cockles in Bannow Bay greater

than Flaxfort Strand

Fluctuations in CI may indicate spawning

Differences in sex ratios – greater number of

females in Flaxfort

PRELIMINARY DISCUSSION PRELIMINARY DISCUSSION

Levels of M. intestinalis infection vary with

position in the sediment & species

Dignean trematodes in both C. edule & M. edulis

– but different levels & stages

Neoplasia identified in C. edule

Large items in the tissues, shell deposits

FUTURE PLANS

Future Work Future Work

ENVIRONMENTAL EFFECTS ON ENVIRONMENTAL EFFECTS ON MORTALITY MORTALITY

From May 2011-October 2011

Lab trials

Lasting 3-4months

Altering conditions e.g. Temperature, Oxygen levels

Observing the effects on bacteria, trematodes,

neoplasia

NEOPLASIA & PRESENCE OF A NEOPLASIA & PRESENCE OF A VIRUS VIRUS

Histology

TEM

Retroviral Activity o Commercial kit

o PERT assay

Heat Shock Proteins &

mutant p53

P53Hsp70

Hsp90

Fig 14: Hsp’s & virus particle

TREMATODE GENETICS TREMATODE GENETICS

14 sites 10-15 animals from each siteInduce cockles to shed Identify using keys e.g. de Montaudouin etal., 2009Extract DNA using methods of Leung et al., 2010Purify and sequence

Fig 15: identification key

OTHER TOPICS/ OTHER TOPICS/ COLLABORATIONS COLLABORATIONS

Contributing to study on cockle genetics

Planning to screen mussels from Bannow Bay to

check for hybrids (see Bignell et al., 2008)

Oral presentations at EMBS 2010

Funding and Partners

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