Presentation Title

Yolk Supply and Consumption at Two Temperatures of the California Grunion

Start Date

November 2016

End Date

November 2016

Location

HUB 367

Type of Presentation

Oral Talk

Abstract

California Grunion Leuresthes tenuis are unique marine teleosts as they spawn out of water during high tides following the full and new moon. Their eggs hatch during subsequent tidal cycles in response to the environmental hatching cue, sea water agitation. In a process known as delayed hatching the Grunion prolongs the incubation period increasing the likelihood of survival. This investigation analyzes the effect of temperature on metabolic activity of embryos of the California Grunion. Oil droplet diameter of the egg yolk was measured by ocular micrometer and compared between embryos incubated at 20˚C and 26˚C. Observations were made during the primary hatching period, 10-15 days post fertilization (DPF), and delayed period, 20-25 DPF. It was expected that the oil droplet diameter would differ over time between embryos incubated at 20˚C and 26˚C suggesting embryos at higher temperatures have higher metabolic rates resulting in increased depletion of yolk supply. A significant difference found between yolk diameter for embryos at the two temperatures 6,12, and 18 DPF indicated rapid depletion of the yolk supply can result from higher temperatures. Hatching success varied. While the 26˚C sample hatched earlier than the 20˚C sample, the 20˚C sample was able to hatch more consistently than the 26˚C sample. Changes in temperature are capable of producing poignant differences in the development of the California Grunion. As climate change has the potential to increase temperatures, favorable conditions for the delayed hatching mechanism could be minimized and potentially threaten the unique developmental strategy of the California Grunion.

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Nov 12th, 3:30 PM Nov 12th, 3:45 PM

Yolk Supply and Consumption at Two Temperatures of the California Grunion

HUB 367

California Grunion Leuresthes tenuis are unique marine teleosts as they spawn out of water during high tides following the full and new moon. Their eggs hatch during subsequent tidal cycles in response to the environmental hatching cue, sea water agitation. In a process known as delayed hatching the Grunion prolongs the incubation period increasing the likelihood of survival. This investigation analyzes the effect of temperature on metabolic activity of embryos of the California Grunion. Oil droplet diameter of the egg yolk was measured by ocular micrometer and compared between embryos incubated at 20˚C and 26˚C. Observations were made during the primary hatching period, 10-15 days post fertilization (DPF), and delayed period, 20-25 DPF. It was expected that the oil droplet diameter would differ over time between embryos incubated at 20˚C and 26˚C suggesting embryos at higher temperatures have higher metabolic rates resulting in increased depletion of yolk supply. A significant difference found between yolk diameter for embryos at the two temperatures 6,12, and 18 DPF indicated rapid depletion of the yolk supply can result from higher temperatures. Hatching success varied. While the 26˚C sample hatched earlier than the 20˚C sample, the 20˚C sample was able to hatch more consistently than the 26˚C sample. Changes in temperature are capable of producing poignant differences in the development of the California Grunion. As climate change has the potential to increase temperatures, favorable conditions for the delayed hatching mechanism could be minimized and potentially threaten the unique developmental strategy of the California Grunion.