Impacts of hypoxia on largemouth bass (Micropterus salmoides) behavior, physiology, and acclimation potential

With urbanization increasing throughout the United States and globally, it is becoming increasingly important to understand the effects of hypoxia (a product of urbanization) on aquatic fauna. This thesis combines two independent, yet complementary, studies to help better understand how hypoxia affects one of the most popular sport fishes, the largemouth bass (Micropterus salmoides). The first study, conducted in 2010-2011 in the Chicago Area Waterway System, contained two parts: 1) quantification of largemouth bass movements in relation to dissolved oxygen through field telemetry, and 2) quantification of physiological parameters in largemouth bass within the study site and three reference sites through field sampling, low oxygen shock trials, and Pcrit analyses (defined as the point at which an animal ceases aerobic respiration and begins anaerobic respiration). Results from this study indicate 1) largemouth bass did not show clear movement patterns out of hypoxic areas, but general avoided these areas altogether, 2) the physiological and nutritional condition of largemouth bass from the study site was similar to reference sites, indicating a lack of chronic stress or limited access to food, and 3) the physiological response of the study site fish to a low oxygen shock of 2.0 mg/L was similar in magnitude to reference sites, as well as similar Pcrit values during respirometry trials, indicating a lack of an improved tolerance to hypoxia for the largemouth bass within the study site. The second study assessed the acclimation potential of largemouth bass to a low oxygen environment using hatchery-reared fish, to determine if largemouth bass had the ability to induce plastic changes to their phenotype within a hypoxic environment. This study held two groups of fish at differing oxygen levels (3.0 mg/L and 9.0 mg/L) for 50 d, where after they were exposed to a low oxygen shock of 2 mg/L. Results of this study indicate largemouth bass acclimated to a low oxygen environment significantly increased hemoglobin and hematocrit levels during an oxygen shock compared to fish not acclimated to low oxygen, indicating largemouth bass, to some extent, possess the ability to impart advantageous changes to their phenotype (e.g., increased oxygen uptake capacity) in order to survive in hypoxic conditions. Together, these two studies help elucidate the potential mechanisms behind which largemouth bass are able to survive in hypoxic conditions, potentially with little cost to their survival.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Natural Res & Env Sciences

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2012

Author dc:creator

• Gaulke, Greggory

Contributors dc:contributor

• Suski, Cory D.
• Wahl, David H.

• acclimation
• stress
• Urbanization
• hypoxia
• physiology
• movement

Statement dc:rights

• Copyright 2012 Greggory Gaulke

Language dc:language

en

Handle dc:identifier

http://hdl.handle.net/2142/34390

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/34390