Erica Midkiff

Date of Award


Degree Name

Biological Sciences


College of Science

Type of Degree


Document Type


First Advisor

Dr. Donald C. Tarter

Second Advisor

Leonard J. Deutsch


The grass pickerel, Esox americanus vermiculatus, is listed as Undetermined on the Vertebrate Species List of Concern in West Virginia. The central mudminnow, Umbra limi, is a disjunct population in Green Bottom Swamp. The lentic, vegetated areas that are required for spawning for the grass pickerel and the central mudminnow have been reduced by residential, agricultural, and industrial developments. Green Bottom Swamp, a naturally occurring wetland of 58 ha, and a nearby mitigated wetland of 29 ha, provides spawning habitat for the grass pickerel and the mudminnow. Fishes were collected in beds of Potamogetan crispus and Ceratophyllum demursum from the old swamp. In December 1994, 15 pickerel were collected from beds of Polygonum sp. in the mitigated wetland. Between April 1995 and July 1996, 65 pickerel (6.67-101.45 mm) and 155 mudminnows (3.89-36.97 mm) were collected from the old swamp. Growth and diet of these fish were determined. Stomach contents of each fish were analyzed, assigned a point value ranging from 0 (empty gut) to 30 (full gut), and expressed as percent frequency of food items per stomach. Cladocerans and copepods were the most abundant In larval pickerel and mudminnows. In juvenile mudminnows, items ranged from larval chironomids and ostracods to cladocerans, while pickerel consumed naiadal stages of large aquatic insects (odonates and corixids) and small fish. Hom, Morisita, and percent similarity indices were used to determine whether a dietary overlap occurred between the phases of each fish. Yolk-sac larvae (YSL) and post yolk-sac larvae (PYSL) of pickerel (Hom = 0.778, Morisita = 0.666, percent similarity = 56.0) and mudminnows (Hom = 0.797, Morisita = 0.750, percent similarity = 57.0) were the most similar. A dietary overlap between fishes was also ascertained. Pickerel PYSL and mudminnow PYSL were similar with values of Hom = 0.900 Morisita = 0.872, and percent similarity = 70.0. Daily growth (mm/day) was calculated. Using back-calculated values from a linear regression (r = 0.9257), daily growth for the pickerel was determined to be 1.10 mm/day compared to only 0.35 mm/day for mudminnows. A pilot study was conducted on the grass pickerel and mudminnow with electrophoretic techniques and a LDH stain to determine if different isozymes were utilized during periods of low dissolved oxygen. Pickerel head and muscle tissue yielded two homotetramers, LDH-B and LDH-A, and one hetrotetramer, LDH-A2B2. The heart tissue displayed only one homotetramer, LDH-B. All mudminnow tissues expressed a single homopolymer, therefore, a single locus expressed for LDH could not be identified. The pl values for stained bands were calculated using linear regression analysis. Fish collected during this period showed no shift in LDH-A or LDH-B even though dissolved oxygen levels varied from 1.33 mg/L to 3.00 mg/L.


Grass pickerel – Ecology.

Grass pickerel – Food.

Esox americanus – West Virginia – Cabell County.

Umbra (fish) – Ecology.

Umbra (fish) – Food.

Umbra (fish) – West Virginia – Cabell County.