Investigating the physiology and behavior of the panamanian bishop fish

Open Access
Ashcraft, Sara Ann
Graduate Program:
Wildlife and Fisheries Science
Master of Science
Document Type:
Master Thesis
Date of Defense:
February 21, 2013
Committee Members:
  • Victoria Anne Braithwaite Read, Thesis Advisor
  • fish
  • physiology
  • behavior
  • gill morphology
  • social information
Aquatic environments can present a number of challenges for the organisms that inhabit them. Some of these challenges are physiological, like the need to take up oxygen from the water through gills, and, as some animals have higher oxygen demands than others, a way to regulate the efficiency of gas exchange may be needed. Teleost fish use their gills for respiration and ion exchange, among other things. These adaptations allow them to inhabit many kinds of aquatic ecosystems, from freshwater to seawater, acidic to alkaline water, extreme high or low temperatures, and hypoxic or anoxic environments. One physiological adaptation that allows them to inhabit different environments is the ability to remodel their gills to change their respiratory surface area, and thus alter their ability to uptake oxygen and discard waste gases. One aim of this thesis was to examine the plasticity of the gills of Panamanian Bishop fish, Brachyrhaphis episcopi. Previous work has shown that these fish differ in temperament with some individuals being bolder than others. Such traits will demand different levels of oxygen thus degree of boldness may be related to gill morphology and specifically how much of the respiratory surface area is exposed to the environment. Here I show that there is no difference in respiratory surface area for bold and timid fish. Other challenges faced by fish are more ecological in nature such as the threat of predation. Many fish have other fish that create a dangerous threat in terms of predation. Fish can adjust their behavior to decrease their risk of predation. One behavioral adaptation that can improve survival is the ability to learn from others, specifically conspecifics. To investigate the use of local enhancement, a type of social information used to locate food; I used B. episcopi sampled from high or low predation areas. Fish from high predation sites may rely more on local enhancement cues compared to low predation conspecifics, but more study is needed.