Giant clam reproduction cycle

Question 1

What are giant clams?

Answer 1

bivalves and benthic

Question 2

How are giant clams sessile?

Answer 2

attached to substrate and unable to move as adults

Question 3

What do giant clams do with their gills?

Answer 3

oxygen and feed

Question 4

How are giant clams hermaphrodites?

Answer 4

they produce both male and female gametes

Question 5

How to giant clams spawn?

Answer 5

externally

Question 6

How is spawning triggered?

Answer 6

by phases of the moon and tides

Question 7

What is SIS?

Answer 7

spawning inducing substance hormone

Question 8

What is triggered by SIS?

Answer 8

neighboring clams

Question 9

How does spawning work?

Answer 9

Sperm is ejected prior to eggs to reduce self-fertilization and promote genetic variation

Question 10

How many eggs to giant clams spawn?

Answer 10

500million eggs per event to help improve chance of success.

Question 11

How long does the egg stage last?

Answer 11

6-12 hours after fertilisation

Question 12

How long does the trochophore stage last?

Answer 12

5-10 hours

Question 13

Explain the veliger stage

Answer 13

• Occurs within 24hrs of fertilisation
• Development of shell (vellum) for protection
• Still in planktonic waters
• Continue to grow for 1 week

Question 14

Explain the pediveliger stage

Answer 14

• A foot develops for attachment to the substrate
• 1-2 weeks
• Starts in planktonic waters and sinks to benthic environment
• Find suitable substrate (attachment sites and mating options)

Question 15

What happens during the spat stage

Answer 15

giant clams grow for 2-3 years into sexually mature adult

Question 16

Explain the adult stage

Answer 16

• Attached to substrate
• Live for 5-6 years
• Often males for 2-3 years before developing eggs and becoming hermaphroditic