Effects of Ultraviolet-B Radiation on Swimming Depth, Gonad Size, Clutch Size, and Clutch Weight of the Guppy, Poecilia reticulata

Burr, Allison

Effects of Ultraviolet-B Radiation on Swimming Depth, Gonad Size, Clutch Size, and Clutch Weight of the Guppy, Poecilia reticulata

Persistent URL

http://hdl.handle.net/10456/8157

Author(s)

Burr, Allison

Date Issued

April 5, 2010

Abstract

In recent decades, the depletion of the Earth’s stratosphere has increased. The thinning of this layer allows greater amounts of ultraviolet-B (UV-B) radiation to reach the Earth’s surface. Freshwater ecosystems experience detrimental effects due to UV-B increase. UV-B can penetrate water from a few centimeters to 10 meters below the surface. This is problematic for many amphibians and fish especially during critical development periods, and can cause increased mortality, sunburn, delayed growth and decreased immunity. However, less is known about the effects of UV-B on adult fish and on offspring of live-bearers. In this study, adult guppies were exposed to varying levels of UV-B radiation. A control group was exposed to incandescent light for 10 minutes, a low dose treatment was exposed to 10 minutes of UV-B, and a high dose treatment was exposed to 30 minutes of UV-B. Exposure times were followed by a 10 minute recovery period. Fish were exposed for 30 consecutive days. During exposure and recovery periods, swimming depth was observed. Gonad size, clutch size, and clutch weight were also looked at once the exposure period was complete. UV-B significantly influenced the vertical distribution of the fish compared to the control group. Swimming behavior returned to normal upon termination of UV-B exposure. Clutch weight was also affected, showing lower weights in female offspring for those treated with a high dosage. Gonad size and clutch size were not affected by UV-B exposure.

First Reader(s)

Rankin, Susan