3.3.8.3. Performance and control
When the tank was set up and clean, the seawater was put into the experiment tank until it reached 25 cm height. The water quality ammonia, pH,
nitrite, and nitrate and salinity were measured before the experiment started. The experiment decreased the salinity at 1 per hour. The amount of freshwater
added to experiment tank in 1 hour was noted. The next hour when salinity was decreased again, the amount of water that was added during previous hour was
taken out first before more freshwater was added to experiment tank. The number of animals ophiuroids: Ophiomastix annulosa and
Ophiocoma cf. dentata used in this experiment is 7 organisms in the experiment and 3-5 ophiuroids for the control.
3
6 7
2 1
4 5
Filter
Bottom current Surface current
Figure 12. Sketch of waterflow during trial with milk. Fixed line shows the surface current; dashed line shows the bottom current; point 1-7 are the points
where milk was dropped. The slowest current among 7 points was at point 3. The other points point 1, 2, 4, 5, 6, 7 are faster than point 3.
To check the organisms during experiments, first their activity was monitored moving, whether their tube feet and tentacles were out or not, and
the arms and body were checked to see if they were normal ophiuroids: arm tips were a little bit elevated and central disk were not swelling pers. obs.. If they
showed any abnormalities ophiuroids: arms curled or loose, body color changed, central disk swelled, not attached anymore, or others. Animals showing any of
these were further checked ophiuroids: turned over, see whether they could turn over again.
During the experiment, the activity of specimens and their condition was noted. After the experiment was complete, the weight and size of the specimens
was measured,and abnormalities noted e.g. showed any autotomy, condition of the arms loosen or curling, condition of the body stiff, wounded, etc.
4. RESULTS AND DISCUSSION
4.1. Results 4.1.1. Species verification
From the species verification through identification with identification key from Clark and Rowe, 1971, it is verified that the species name are Ophiomastix
annulosa red ophiuroid, Ophiarachna incrassata green ophiuroid, Ophiocoma cf. dentata black ophiuroid, and Fromia milleporella red starfish. The picture of
these species can be seen in Appendix 29 .
4.1.2. Thermal limit and salinity stress experiment
In this study, several experiments were done with several species of tropical echinoderm, from class ophiuroidea and asteroidea. The experiments
were: 1 hourly upper thermal limit, 2 daily upper thermal limit, 3 hourly lower thermal limit, and 4 hourly decrease salinity. The general results of this study
can be seen in Table 2 and details results and graphs are provided below. Table 2.
Temperature and salinity limit of selected tropical Ophiuroidea
Ophiomastix annulosa,
Ophiarachna incrassata,
Ophiocoma cf.dentata and Asteroidea Fromia milleporella
Organisms Thermal Limit
C 100 not responding
Salinity Limit psu
100 not responding
Upper Lower
Decrease Hourly
Hourly repeat
Daily Hourly
Hourly
Ophiomastix annulosa
nE: 10 TE1: 26.0
TE2: 36.5 nC: 8
TC1: 25.0 TC2: 25.9
nE: 6 TE1: 26.0
TE2: 37.0 nC: 5
TC1: 25.9 TC2: 25.9
nE: 10 TE1: 26.2
TE2: 35.0 nC: 8
TC1: 25.0 TC2: 25.0
nE: 10 TE1: 27.0
TE2: 12.8 nC: 4
TC1: 25.0 TC2: 25.9
nE: 7 SE1: 36
SE2: 20.5 nC: 5
SC1: 36 SC2: 36
Ophiarachna incrassata
nE: 8 TE1: 25.9
TE2: 37.2 nC: 8
TC1: 24.2 TC2: 25.5
nE: 8 TE1: 26.0
TE2: 34.0 nC: 3
TC1: 25.3 TC2: 24.8
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