Theses and Dissertations

Issuing Body

Mississippi State University


Dibble, Eric

Committee Member

Schramm, Hal

Committee Member

Allen, Peter

Date of Degree


Document Type

Graduate Thesis - Open Access


Wildlife and Fisheries Science

Degree Name

Master of Science (M.S.)


College of Forest Resources


Department of Wildlife, Fisheries and Aquaculture


The alligator gar Atractosteus spatula is a euryhaline fish found in the Gulf of Mexico and surrounding drainages. However, the extent of its hypo-osmotic abilities are not well understood. To determine effect of salinity on growth, metabolic rate, and osmoregulation abilities the following question was developed: when does the alligator gar have the osmoregulatory capabilities to survive in hyperosmotic environments? To answer this question, two different age groups (60 and 330 days after hatch [DAH]) of juvenile alligator gar were exposed to 4 different salinities (0, 8, 16, and 24 ppt) for a 30-day period. Specific growth rate, oxygen consumption rate, plasma osmolality, plasma ion concentrations, tissue Na+, K+-ATPase activities, and drinking rate were measured. I determined that the 60 DAH alligator gar had a greater ability to grow and regulate ions than did the 330 DAH alligator gar in increased salinity.