Date of Award

Spring 2022

Degree Name

Bachelor of Science

Department

Biology; College of Arts & Sciences

First Advisor

Dr. Chad Hoefler

Abstract

Fresh water makes up about 0.8% of the Earth’s surface and is home to six percent of its species. Environmental warming is projected to have a significant effect on freshwater systems as the century progresses. They are susceptible to irreversible damage because fresh water availability and temperature is dependent of climate. The Clarias gariepinus, or the African Catfish, is popular among aquaculture in Africa and Asia because of its rapid growth, quick reproduction, and hardiness. The goal of my thesis was to examine the effect of environmental warming and elevated temperatures on the growth and physiology of Clarias gariepinus populations through a review of current literature. Clarias gariepinus that inhabited water temperatures of 40°C experienced lethality. Gastric Emptying Time (GET) decreased as water temperature rose. Food Conversion Rate (FCR) and Efficiency (FCE) both increased as water temperature rose. An increased GET with an increased FCE is consistent with similar research. Based on previous work this should have also increased growth rate, but it did not in these studies. No significant difference was observed between the growth of populations in different temperatures. Studies on other freshwater fish species have been done and some exhibit negative ecological results. Environmental warming effects on additional freshwater species have been variable. Only a small temperature range was observed in C. gariepinus, more values can depict if growth increases, decreases, or is sustained at higher temperatures. Comprehensive research needs to be done to examine trophic cascade effects.

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Effects of Environmental Warming on Clarias gariepinus Growth and Physiology

Fresh water makes up about 0.8% of the Earth’s surface and is home to six percent of its species. Environmental warming is projected to have a significant effect on freshwater systems as the century progresses. They are susceptible to irreversible damage because fresh water availability and temperature is dependent of climate. The Clarias gariepinus, or the African Catfish, is popular among aquaculture in Africa and Asia because of its rapid growth, quick reproduction, and hardiness. The goal of my thesis was to examine the effect of environmental warming and elevated temperatures on the growth and physiology of Clarias gariepinus populations through a review of current literature. Clarias gariepinus that inhabited water temperatures of 40°C experienced lethality. Gastric Emptying Time (GET) decreased as water temperature rose. Food Conversion Rate (FCR) and Efficiency (FCE) both increased as water temperature rose. An increased GET with an increased FCE is consistent with similar research. Based on previous work this should have also increased growth rate, but it did not in these studies. No significant difference was observed between the growth of populations in different temperatures. Studies on other freshwater fish species have been done and some exhibit negative ecological results. Environmental warming effects on additional freshwater species have been variable. Only a small temperature range was observed in C. gariepinus, more values can depict if growth increases, decreases, or is sustained at higher temperatures. Comprehensive research needs to be done to examine trophic cascade effects.