I started with lab experiments to determine, how big will the Eurytemora affinis from Gulf of Riga grow at different temperatures and food densities.
I will grow them at 7, 14 and 21 degrees, and feed them with Brachiomonas sp, at 2500, 5000 and 10 000 cells/ml every second day.
These tiny animals grow at most 1.5mm long, and represent the most important item in the diets of herring, herring larvae, other pelagic fish and even invertebrates in the Gulf of Riga ecosystem.
Although it is known that they tend to get smaller in summer, it is know known, how much is it because of temperature, and how much because of food. Based on measurements done during one season in 1979, Simm (1980) showed that they can loose up to 50% of their body mass by summer. 50% smaller animal means that herring as a visual feeder, needs to work twice as much to have the same amount of energy.
The experiment will take place in our lab in Tartu (Vanemuise 21). Currently, I'm doing a pilot (to learn how to maintain their culture), at 7 degrees C (food: 5000 cells /ml); and at 14 C (food: 2500, 5000 and 10 000 cells/ml, every second day).
All nauplii hatched from 10 females were placed in 1 L of filtered seawater, in the 2L beakers.
A nauplii, couple of weeks after hatching at 7 C.
2 L beakers in the water bath maintaining the 14 C.
Measurements during the experiment; from 7C treatment. I usually catch an animal alive, intoxicate with the carbonated water, take photos, measure, and leave them recovering in seawater, and place them back after they regain their activity.