Post on 13-Jul-2020
Estación de Ciencias Mariñas de Toralla
ECIMAT
Short and Long-term effects of salinity stress episodes on Cerastodema edule: Thread drifters vs. Sedentary settlers
L G Peteiro, D Costas, A Martinez, N Costoya, R Rodriguez, S Gonzalez, D Villafaña,
C Olabarria, E Vázquez
Ph
oto
: La
van
dei
ra jr
(La
Op
inio
n A
Co
ruñ
a)
26/10/2016
21/01/2016
24/04/2016
28172 Tm
2015 FAO- Global Production Statistics
Spain/Galicia ≈ 10% of European
production
2015
C. edule
Ph
oto
: P
.S.
(El C
orr
eo G
alle
go)
Trocophore Veliger
Pediveliger
Thread-drifters
Primary settlement
Secondary Settlement
juveniles
♀ ♂
May-July
4-5 weeks
Thread-drifters
juveniles
♀ ♂
Salinity Optimum: 25 (Verdelhos et al. 2015)
Salinity Optimum: 30-35 (Kingston,1974)
Primary settlement
Secondary Settlement
May-July
?
What are the physiological responses of early-settlers to drops in salinity?
Do they differ between thread-drifters and sedentary juveniles?
Experimental Design:
2 size classes:
-Sedentary Settlers ≈ 8mm
-Thread-drifters ≈ 4mm
4 replicates x 8 Salinity treatments:
2, 5, 10, 15, 20, 25, 30 and 35
Physiological measurements:
-Oxygen Consumption
-Clearance Rate
-Ammonium Excretion
-Mortality
-Growth
Day 2 and Day 7
Spat reared at the laboratory Salinity 35
1 Week
DAY 2 Acute stress
Isolation reflex >10 Linear increase
<20
<10
>20 ≈ Plateau
Isolation reflex >25 ≈ Plateau
<10
<10
>20 ≈ Plateau
DAY 2 Acute stress
Isolation reflex <10
<10
DAY 2 Acute stress
Regulation of FAAP
Ammonium excretion
Isolation reflex <10
<10
DAY 2 Acute stress
Regulation of FAAP
Ammonium excretion
DAY 2 Acute stress
ANOVA; p<0.001
ANOVA; p=0.716
ANOVA; p<0.001
ANOVA; p=0.073
Length
Weight
No activity bellow 15 Isolation reflex Progresive increase with salinity
No activity bellow 15 Isolation reflex 100% Mortality at day 4 bellow 15 Anaerobic metabolism
At day 7 no more differences between salinities
Acclimation
Acclimated
DAY 7 Acclimation
DAY 7 Acclimation
Acclimated
Not yet!
DAY 7 Acclimation
ANOVA; p<0.001
ANOVA; p=0.944
ANOVA; p<0.001
ANOVA; p=0.779
Length
Weight
Thread-drifters
juveniles
♀ ♂
Salinity Optimum: 25 (Verdelhos et al. 2015)
Salinity Optimum: 30-35 (Kingston,1974)
Primary settlement
-
May-July
Stage-specific habitats
Salinities < 15 are lethal after 4 days
Thread-drifters acclimated after 1 week
Fisheries management
+ Eurihaline
Thread-drifters
juveniles
♀ ♂
Salinity Optimum: 25 (Verdelhos et al. 2015)
Salinity Optimum: 30-35 (Kingston,1974)
Primary settlement
-
May-July
Salinities < 15 are lethal after 4 days
Thread-drifters acclimate after 1 week BUT growth at 15
+ Eurihaline
Salinity stress has any
long-term effects?
Long-Term Experimental Design:
Thread-drifters ≈ 2mm
3 replicates x 4 Salinity treatments: 5, 15, 25 and 35
2 Days
Spat reared at the laboratory Salinity 35
10 Months
Salinity ≈35
Growth: - End of estrés -5 days recovery -1 month recovery -10 month recovery Gametogenetic index
ab b
bc c
2 days stress: Slower growth at low salinities
ab b
bc c
2 days stress: Slower growth at low salinities
Irreversible damage at Salinity 5
a a
b
5 days recovery: Salinity 35 keeps advantage
a
a
a
5 days recovery: Salinity 35 keeps advantage
1 month to catch up with growth after the stress episode
Advanced
Gonad Restoration
Post-spawning
Ripe
Initial
Resting
10 months recovery:
Delay on gametogenesis for Salinity 15 ? Why??
χ 2 =39.59 p=0.0002
Martinez-Castro & Vazquez 2012
(March 2016)
a
b
a
Higher metabolic demand Related to gonad
restoration
Advanced
Gonad Restoration
Post-spawning
Ripe
Initial
Resting
10 months recovery:
Delay on gametogenesis for Salinity 15 ? Why??
χ 2 =39.59 p=0.0002
Martinez-Castro & Vazquez 2012
(March 2016)
Thread-drifters
juveniles
♀ ♂
-
- Salinities < 15 activate the “isolation reflex” and become lethal after 4 days of exposure.
- Salinity of 5 cause irreversible damage after 2 days
- Salinity <20 CR O2 consumption excretion
-Thread drifters acclimated after a week and are able to
catch up with growth in one month.
-Sedentary settlers already lost certain eurihalinaty
+ Eurihaline Gametogenesis ?
Growth
The results shown in this presentation have been obtained with financial support from the Spanish Ministerio de Economia y Competividad to the project MARISCO, and a posdoctoral grant from Xunta de Galicia.
Acknowledgements:
Estación de Ciencias Mariñas de Toralla
ECIMAT