Major

Marine Biology

Advisor

Forrester, Graham

Advisor Department

Natural Resources Science

Advisor

Wilga, Cheryl

Advisor Department

Biological Sciences

Date

5-2013

Keywords

Escape responses; marine ecology; functional morphology; animal behavior; predator-prey interactions; Bridled Goby

Abstract

The Effects of Refuge Abundance on Escape Responses of the Bridled Goby (Coryphopterus glaucofraenum)

Russell P. Dauksis

Major

Marine Biology

Advisor

Dr. Graham Forrester

Advisor Department

Natural Resources Science

Date

5-2012

Keywords

Escapology, marine ecology, functional morphology, animal behavior, predator-prey interactions, Bridled Goby, Coryphopterus glaucofraenum

Abstract

Interactions between predators and prey species are arguably the most pervasive and important events in ecology. Predators have strong effects on the distribution and abundance of prey in virtually all environments. In the long-term, it is therefore hardly surprising that selective mortality imposed by predators has shaped a wide array of prey behaviors that can be viewed as evolved responses to avoid predators.

Although prey exhibit a bewildering diversity of “strategies” to avoid predators, including camouflage, hiding in safe places, confusion, distraction and confrontation, most animals will sometimes simply flee when approached by a potential predator. For fish, the flight response has a stereotypic form, during which escaping fish exhibit a lateral contraction of the body into a “C” (known as a C-start) followed by a contraction of the opposite lateral muscle. Prey fish are commonly assumed to escape from predators with a maximal locomotor effort, but this may not always be the case. The presence of refuges may alter this escape response by allowing for an area of safety in close proximity.

I will study escape responses of the bridled goby, a Caribbean reef fish, in laboratory tanks that are as close to natural as possible. This will create conditions that are ecologically realistic and also allow detailed filming of the escapes. My study will thus be novel in taking an interdisciplinary approach; spanning ecology as well as animal behavior and functional morphology. I will test the hypothesis that reaching a refuge, through more focused directionality towards them, takes priority over maximizing locomotor performance in determining the characteristics of escape responses.

The fleeing of startled bridled gobies will be recorded with high-speed video equipment under the two treatments of refuges absent and refuges present. I will first use a model predator as the stimulus and then use a live predatory fish to make sure that the escape responses of the gobies are the same under both conditions. Model predators have been used successfully in prior experiments, and allow for the direction speed and timing of the predator stimulus to be easily manipulated. Muscle contraction patterns, directionality, acceleration, and velocity will all be analyzed from the video footage acquired from these experiments. It is predicted that the gobies will exhibit a lower energetic investment in escaping when refuges are providing safety.

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