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Mud Crab Culture Revision

Total questions: 13

Worksheet time: 7mins

Name
Class
Date
1.

Four species of mudcrab has been the focus of both commercial fishries and aquaculture production. Which of the following species is important to Brunei Darussalam?

a)

Scylla olivacea

b)

Scylla tranquebarica

c)

Scylla serrata

d)

Scylla paramamosain

2.

State one reason why mud crab has high consumer demand and market price.

a)

High meat yield

b)

Highly cannibalistic

c)

Hatchery produced crablets easily obtained

d)

Highly innovative culturing technique

3.

How many spines does Scylla serrata has between its eyes?

a)

5

b)

6

c)

9

d)

4

4.

State the function of the fourth legs found in mud crabs.

a)

For crushing food

b)

For cutting food

c)

For walking

d)

For swimming

5.

The following image is an image showing a male mudcrab.

a)

True

b)

False

6.

State the stage in the lifecycle of the mudcrab after the eggs hatched.

a)

Zoea

b)

Megalopa

c)

Crablet

d)

Post Larvae

7.

Sub-adult and adult crabs eat attched bivalves, marine detritus, molluscs, crustacean and fish. Which type of feeding habit does mudcrab exhibit?

a)

Carnivorous

b)

Herbivorous

c)

Omnivorous

d)

Piscivorous

8.

One of the major challenge in crab culture in open system is cannibalism. Which of the following is a strategy to significantly improve surivival rates in culture?

a)

Culturing crabs at higher density

b)

Culturing crabs in individual containers

c)

Provision of adequate amount of food for crabs

d)

Provision of adequate hiding space for crabs

9.

Which of the following best describe the premolt or proecdysis stage in crab moulting cycle

a)

Stage where crabs gets out of old shell and take up water rapidly

b)

Stage where hard outer layer of shell separates from membranous layer

c)

Stage where crab expands its body and limbs by taking in water

d)

Stage where the carapace hardens but walking legs are still flexible

10.

Which of the following environmental factor affects hatching time and release of larvae in mudcrab reproduction?

a)

Salinity

b)

pH

c)

Temperature

d)

Dissolved oxygen

11.

Which of the following describes the on-growing sytsem shown in the picture?

a)

Pond culture

b)

Pen culture

c)

Cage culture

d)

Cellular system culture

12.

Which of the following best descibe the process where mudcrabs are identified, held and fed for a period of few weeks before they are eventually marketed.

a)

Crab Fattening

b)

Crab Holding

c)

Crab Boarding

d)

Crab Loading

13.

Which of the following problem in mudcrab culture can be reduced by the provision of essential fatty acid in diet and optimum water temperature in culture.

a)

Limitations of seed supply

b)

Incomplete moulting

c)

Cannibalism

d)

Disease transmission