There exists no statistically significant difference between the Barred tiger salamander's length, weight, and gill length with respect to Playa Lake and Lake Cove water environments. Ho11: PL = LC 2. There exists no statistically significant difference between the Barred tiger salamander's length, weight, and gill length with respect to Playa Lake and Lake Cove water environments. Ho12: PL = LC

3. There exists no statistically significant difference between the Barred tiger salamander's length, weight and gill length with respect to the Playa Lake and the Earthen Stock Tank water environments. Ho13: PL = EST

4. There exists no statistically significant difference between the Barred tiger salamanders' length, weight, and gill length with respect to the Playa Lake and the Industrial Wastewater #1 water environment. Ho14: PL = IW#1

5. There exist no statistically significant difference between the Barred tiger salamanders' length, weight, and gill length with respect to the Playa Lake and the Wastewater #2 water environment. Ho15: PL = IW#2

Definition of Terms

Throughout this report the following list of terms and concepts are used most extensively; therefore, in order to avoid any misunderstanding, they are operationally defined as follows:

Barred tiger salamander: A small lizard-like amphibian. For the study the Barred tiger salamander (Ambystoma tigrinum) was selected due to the amphibians abundance of number and its availability in the area.

Texas Wetlands: Areas that are inundated or saturated by surface or groundwater at a frequency and duration sufficient to support, and that under normal circumstances do support, a prevalence of vegetation typically adapted for life in saturated soil conditions. Wetlands generally include swamps, marshes, bogs, and similar areas. (33CFR § 323.2, and 40 CFR § 230.3, The Environmental Law and Compliance Handbook by James F. Berry, J.D., Ph.D., Mark S. Dennison, J.D.) The Texas Commission on Environmental Quality has incorporated the playa lakes of the Texas Panhandle into the definition of wetlands with specific regulations; Title 13 § 401.004; Title 2 § 11.502; Title 2 § 26.048; (Texas Environmental Laws, 2004 Edition, Thomson West).

Water contaminants: Any substance introduced into the water, which has the effect of rendering water toxic or otherwise harmful (The Condensed Chemical Dictionary, 9th edition, 1977, Gessner G. Hawley, Van Nostrand Reinhold, Company).

Length Measurement: Measurement of the individual salamanders in centimeters from tip of tail to the front of the snout to determine their overall length dimension.

Weight Measurement: Measurement of the mass in grams of the individual salamanders.

Gill Measurement: Length measurement in centimeters of the gill located on the left side of the salamanders' heads extended fully from the point of attachment to the tip.

Metamorphosis: The ability of the tiger salamander to transform from the aquatic neotenic form with gills to the terrestrial form to live on land. Both can develop to complete sexual maturity, but the neotenic form remains aquatic with external gills and a main fin on the tail. It is a marked change in the mode of life and form of the species.

Terrestrial: Landbased stage of the Barred tiger salamander. Usually the salamander will undergo metamorphosis, become terrestrial and develop to a mature adult living outside the aquatic habitat.

ANOVA: Method for statistical analysis of more than one variable. (Phillips, John L., How to Think About Statistics, 6th Edition, W.H. Freeman and Company, New York, 2001).

"t" Test: Statistical test used for statistical comparison of two means to determine whether or not they are identical. Two sets of data may: one from a new experiment and one for control; two results of split samples from two laboratories, or; a new analytical and existing analytical method. (Lee, C.C., editor in chief; Shun, Dar Lin, associate editor; Handbook of Environmental Engineering Calculations, McGraw-Hill, New York, 1999).

Independent Variable: A variable that is manipulated by the experimenter or a treatment variable. (Phillips, John L., How to Think About Statistics, 6th Edition, W.H. Freeman and Company, New York, 2001).

Dependent Variable: A variable whose values are determined by those of the independent variables or measurement. (Phillips, John L., How to Think About Statistics, 6th Edition, W.H. Freeman and Company, New York, 2001).

Statistical Significance: Experimental results that are not likely to have occurred by chance alone: Results that are unlikely to have occurred by chance. (Koosis, Donald J., Statistics A Self-Teaching Guide, fourth edition, John Wiley & Sons, Inc., 1997).

Rationale for the Study of the Selected Species

Regardless of the research investigative situation, both the independent variable(s) and the dependent variable(s) are chosen according to a pre-determined set of criteria. The investigator of this study established...

Taxonomic soundness and ease of recognition for the purpose of accurate sample selection.
2. Cosmopolitan distribution of the sample.

3. Numerical abundance of the sample.

4. Low genetic and ecological variability of the sample.

5. Large body size of the sample

6. Long life history and mobility of the sample.

7. Auto-ecological awareness by the sample.

8. Laboratory tolerance by the sample.

Taxonomic categories are best described as those that constitute a sample of likeness wherein there exists shared trait commonalties rather than shared relationships. For example, all salamanders share a relationship within six identifiable types of salamanders, yet each grouping has its own identifiable trait catalogue. The chosen species for the present study was the Barred tiger salamander rather than other salamander species because the Barred tiger salamander resides in the Texas Panhandle, although its zoological relatives live in other land areas through out the United States. With reference to the Barred tiger salamander's cosmopolitan distribution, only those Barred tiger salamanders aquatic-bound were studied -- not Barred tiger salamanders that are terrestrial inhabitants. This was necessary as the primary purpose was to investigate the effects on, and differences between, aquatic environments on developmental indices of the Barred tiger salamander.

Any investigative study, whether of mammals or other fauna, sedimentary, igneous or metamorphic rock formations, or flora, must provide the investigator a sufficient number of units to be observed, evaluated, and assessed. The Barred tiger salamander provided a sufficient number at this time in the ecological cycle. Had there existed only a selected few tiger units available for investigation, the study would have been greatly limited as to scope and inferential ability. Further, knowing that an acceptable life span of a Barred tiger salamander is upwards to 20 years provided the investigator with more than sufficient time to record any changes aquatic pollutants had on the organism. In addition, knowing the Barred tiger salamander can survive in a controlled environment, one even pet-oriented, provided additional assurances that the Barred tiger salamander could exist in a treatment situation (independent variable effect) without immediate demise.

Necessary to all well-controlled investigative studies is the need for low subject variability. When increased variability occurs there exists the possibility of error control or bias when interpreting study results; thus contaminating the results of the research endeavors. Barred tiger salamanders of the Texas Panhandle, by having limited mobility as well as low genetic and ecological variability, are therefore self-controlled in terms of possible error due to extraneous influences that cannot be controlled or measured1.

Although the Barred tiger salamander has been used in the past in environmental exposure studies for pesticides, herbicides, and ecological risk assessments, there exists limited use of the aquatic species in continued research for contaminant accumulation and its effects2. Amphibians are considered to be extremely sensitive to ecosystem changes: Therefore, the health of the salamander is expected to mirror the health of the inhabitants as an ecological population. Using the Barred tiger salamander as an indicator species would, therefore, provide a study organism that is sensitive to environmental change so that developmental changes or alterations could be recorded and assessed. Even with naturally occurring anomalies, such as droughts, floods_, and dust storms, the species' population numbers are sufficient enough to permit a determination of any correlation to contaminants other than "normal" variations.

CHAPTER II

PHYSIOLOGY, MORPHOLOGY, and RANGE

Taxonomic Hierarchy

Kingdom: ANIMALIA

Phylum: CHORDATA

Subclass: LISSAMPHIBIA

Order: CAUDATA

Family: AMYSTOMATIDAE

Genus: AMBYSTOMA

Species: Ambystoma Tigrinum

Subspecies: Ambystoma Tigrinum Mavortium (Baird, 1850)

The neotenic form of the Barred tiger salamander (Ambystoma Tigrinum Mavortium) has often been referred to in the literature as a "waterdog" or "mud puppy." Although many individuals use these terms to denote the species studied here, it is an erroneous usage. The true "water dog" is associated with the family Proteidae, genus Necturus. Therefore, the Barred tiger salamander is not the true "water dog" (Miller, 2000).

Range. The Barred tiger salamander, Ambystoma tigrinum, ranges from Nebraska to the Mexican Plateau (Miller, 2000). They can also be found in prairie and forested areas in which moisture is adequate (Collins, 1982). Presented in Figure 2.1 is a cartographic representation of the Barred tiger salamander's inhabited area.

INSERT FIGURE 2.1 HERE

Description. With moist skin and long tails for swimming, the Barred tiger salamander represents one of the largest groups of mole salamanders. Distinguishing markings of the adult include light spots and bars or blotches on a dark background. The body is robust, with 14 or fewer vertical grooves on each side of the body between the front and hind limbs. The color of the belly of this particular salamander is of a mottled light…