Effects of an artificial photothermal cycle on the reproduction of the shortfin silverside, Chirostoma humboldtianum, Valenciennes, 1835 (Pisces: Atherinopsidae)
Abstract
We report, for the first time, the controlled reproduction of the shortfin silverside fish (Chirostoma humboldtianum, Valenciennes, 1835) and determine the effects of the artificial photothermal cycle (APC) on male and female reproduction. Two trials were carried out utilizing an 81-day APC, which consisted of gradual increases and decreases of temperature and photoperiod. The initial conditions of 13 °C temperature and a photoperiod of 9L/15D were followed by increases of 1 °C and 30 min until 14L/10D at 23 °C was reached. Thereafter, the cycle was completed when the initial conditions were reached by decreasing at the same rate. The trials were carried out in two 4000-L circular tanks; one treated and one control. In the first trial the time and percent motility of the sperm, number and viability of sperm and semen consistency were evaluated, the control tank was maintained at the conditions of the Experimental Production Plant (EPP) at 17.4 °C and 11L/13D. In the second trial the broodstock were subject to a second APC, and thereafter, this tank as well as the control tank were maintained under the climatic conditions of EPP during other 48 days. In both tanks, the number of spawns, number of eggs and the survival rates of eggs and larvae were evaluated. In the first trial, the results indicated that male brooders responded adequately to the photothermal stimulation of 19 °C and 12L/12D, females did not respond to this first stimulation. In the second trial, females responded at 19 °C and 12L/12D presenting multiple spawns. At the end of this experiment 48 spawns and more than 26,000 fertilized eggs were obtained, with more than 80% of survival.
- Publication:
-
Aquaculture
- Pub Date:
- 2004
- DOI:
- 10.1016/j.aquaculture.2004.08.014
- Bibcode:
- 2004Aquac.241..575B
- Keywords:
-
- Artificial photothermal cycles;
- Reproduction;
- Chirostoma humboldtianum;
- Sperm;
- Roe;
- Eggs