I wanted to record this in the Experiment Section, but there is no "Post New Thread" button! So here I am!
Experiment Title: Density of copepod nauplii when feeding pelagic larvae trial
Purpose of Experiment: To determine the better density of copepod nauplii to promote survival of extra small pelagic larvae. Trial will be an n of 1, so not a real experiment, with 10 nauplii per ml expected to be produced by 15000 adult copepods in 1.5 liters daily, and 100 nauplii per ml expected to be produced by 150,000 adult copepods in 1.5 liters daily. Assumption is that the adults will produce an average of 10 nauplii per adult per day.
Hypothesis: I would expect that 10 nauplii per ml for pelagic larvae should be the equivalent of 10 rotifers per ml for clownfish larvae.
Starting Date of Experiment:
8/21/15 night of
Dascyllus aruanus hatch
Ending Date of Experiment:
8/24/15 only one hapless larva in the 10N/ml jar, 2 or 3 hunting and striking larvae in the 100N/ml jar
Materials:
1.5 liter PETE clear plastic jars (2)
rigid airline connected to air supply
water bath set at 80F big enough to hold the jars, heater and water.
sufficient
Parvocalanus crassirostris to provide 15000 adults to one jar, and 150,000 adults to the other.
filters to remove copepodites from culture
Isochrysis galbana, live with occasional other live algaes in combination as available
10 watt LED screw in light bulb about 2 feet from cultures
~ 100 Eggs of
Dascyllus aruanus, ready to hatch.
Procedure for the Experiment: 1. Set up jars in water bath, with airlines to receive eggs and culture larvae
2. Harvest eggs on hatch night, not the whole nest, I am guessing there were 100 eggs scraped off the tile.
3. Roughly, add half the eggs to jar 1 and half the eggs to jar 2
4. Incubate 2 days until eggs hatch and eyes begin to darken
5. Add 1500 adult P. crassirostris to Jar1, and 15,000 to Jar 2
6 Incubate and observe larvae daily.
Experiment Constants: 1.5 Liter jars, the salinity of the water, the amount of water used , temperature of water bath, air supplied, approximately equal numbers of eggs
Experiment Variables:
Independent variable: The number of
P. crassirostris adults added, and their expected nauplii population, 10 per ml and 100 per ml.
Dependent variable: D. aruanus survival
Experiment Data: 8/24/15
- only one hapless larva in the 10N/ml jar,
- 2 or 3 hunting and striking larvae in the 100N/ml jar
Conclusion: 100 nauplii /ml of P. crassirostris may have contributed to the survival of damsel larvae Dascyllus aruanus. Seemed to work better than only 10 N/ml. I've proven nothing since there are no replicates or statistics, but I have shown that it is possible to raise larvae with that concentrated nauplii population, contrary to the ideal prey/ml concentration known in rotifer dogma, 10/ml.
Were I to repeat the trial, I would do replicate studies, count the nauplii throughout the experiment to confirm populations, and be more exact about the numbers of larvae added to each unit jar. I might wait until after hatch to add the larvae as well, to avoid any issues with hatch rate.
<message edited by KathyL on Tuesday, August 25, 2015 6:31 PM>