Artemia franciscanaNorth American brine shrimp

(Crustacea, Anostraca)

HATCH

Artemia

life

cycle

fertilized eggs in

brood sac

Adult female

winter ‘eggs’

Artemia franciscana (dry, encysted ‘winter eggs’)

‘Paint’ dry cysts on double-stick tape with small, soft, dry paintbrush

Method Apaint cysts on sticky circle

plastic petri dishtransparency strip with grid

10 mm x 10 mm

strip of double-stick tape covers grid

tape holds strip to dish

Method B

Cysts painted on sticky grid with brush

STUCK-on ARTEMIATechnical Advantages

easy handling & transfer of cysts

uses small, quantifiable number of cysts

follow development of individual cysts

cysts stay in single focal plane

use dissecting or compound microscope

manipulation of many relevant variables

Hatching of encystedArtemia embryosA1-A2: Encysted

late gastrula stage(immersed in sea water and stuck to tape)

B: Cyst hydrates and swells; cyst wall splits

C1-C2: “Umbrella” stage emerges (membrane-bound)

D1-D2: Nauplius larvae are free swimming

A1

B

A2

C1

C2

D1 D2

Each day, use pipet to remove and count hatched, swimming nauplius larvae

Treatment Group (control or experimental) _________________ Initial number of cysts in dish _____

# of hatched nauplius larvae

removed

Cumulative # of hatched nauplius

larvae (day 1 + 2 + 3…)

Cumulative hatching % (cumulative # of hatched

larvae / initial number of cysts X 100)

Day 0 start

Day 1(24 h)

Day 2(48 h)

Day 3(72 h)

Day 4(96 h)

0

50CONTROL

0 0%

22 22 44%

39

11 33

6

1 40

78%

80%

66%

0

20

40

60

80

100

day 0 day 1 day 2 day 3 day 4

%HATCH

Typical hatching curve:

2. ambient light effects during hydration

5. second hydration

1. dry cysts exposed to thermal extremes

3. temperature effects during hydration

4. salinity effects

Examples of experimental variables that may affect hatching curves

6. oxygenation effects during hydration

7. environmental toxicant effects

8. irradiation effects on dry or hydrating cysts

Measurements & End-points

* Hatching % *

hatching time-coursedevelopmental anomalies

larval motility molting & growth

'N Cyst'N Cyst

A sea monkey's no monkey or chimp. It's crustacean - better known as brine shrimp.

This genus Artemia Can deal with extremia.

As a cyst stage, its hardly a wimp.