Date of Award

2017

Document Type

Thesis

Degree Name

Bachelors

Department

Natural Sciences

First Advisor

Gardiner, Jayne

Area of Concentration

Marine Biology

Abstract

The present study investigated the effects of tactile cues on rheotaxis in the blind Mexican cave fish, Astyanax mexicanus. It was hypothesized that an increase in substrate roughness would increase orientation ability when the lateral line or vision were ablated. Reversible lateral line ablations were performed with a treatment of 0.1mmol/L cobalt chloride in calcium free water for 24 hours prior to testing fish. Test fish were analyzed in groups of ten and evaluated for their ability to orient on a smooth or rough substrate, with and without their lateral line system, and in light and dark conditions. Rheotaxis, for the purposes of this study, was classified into rheotactic accuracy, the proportion of fish orienting (+/-) 10 degrees into the flow, and rheotactic ability, the proportion of fish orienting (+/-) 30 degrees into the flow. The results of this study demonstrate that the roughness of the substrate does not enhance or hinder the rheotactic accuracy or the rheotactic ability of blind Mexican cave fish, which suggests that tactile cues are either not involved in rheotaxis or that both the smooth and rough substrates provide sufficient stimuli for orientation.

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