Simulation of the summer?autumn temperature variation on Stomolophus meleagris polyp reproduction: effect of three frequency rates

OLGUÍN JACOBSON, C.; SCHIARITI, A.; CARVALHO-SAUCEDO, L.; OCAMPO, L.

Barcelona

Simposio; 5th International Jellyfish Bloom Symposium; 2016

Institut de Ciències del Mar - CSIC

Understanding the effect of temperature in the reproduction of Scyphozoans is limited. To our knowledge, no information is available to describe how periodic fluctuations due to seasonal changes in sea temperature affect polyp reproduction dynamics. We created a continuous thermal wave in the laboratory, with a peak at 30° C and a minimum at 20° C, simulating the summer-autumn seasonal temperature change. We exposed mother-polyps of S. meleagris to three treatments in which the thermal wave repeated after 7, 14, and 28 days to produce a high, medium, and low frequency wave, respectively. Asexual reproduction (number of ephyrae, podocyts, and new polyps) was registered at the crest and trough of each thermal wave for three months. We found that the frequency wave had a significant effect on all reproductive variables, but no effect was detected when compared between the crest and trough of the thermal wave. A high frequency wave lead predominantly to podocyst production with negligible ephyrae and new polyp production at a lower survival rate. More podocysts (approximately 40%) were produced at both low frequency wave at the crest, and medium frequency wave at the trough. More ephyrae (almost double) were produced at both medium frequency at the trough and low frequency at the crest. These results indicated that a high frequency wave was a stressful condition for ephyrae recruitment and polyp survival. The highest ephyrae production found at the low frequency wave at the crest agrees with the hypothesis that suggests more jellyfish production at warmer temperatures in temperate species. Further research is needed to understand the dynamics found at the medium frequency wave.