Semester of Graduation

Summer 2019

Degree

Master of Science (MS)

Department

Renewable Natural Resources

Document Type

Thesis

Abstract

The global ornamental fish trade has expanded over the past 20 years, requiring captive rearing methods to be improved or developed for species of interest. Aquaculture of desirable species is preferable over wild harvest to conserve natural habitats and biodiversity. This thesis focused on improving culture methods for Golden Topminnows Fundulus chrysotus and developing culture methods for Bluenose Shiners Pteronotropis welaka, both native fishes of the southeastern United States with ornamental demand. A combination of reproductive metric analyses, examination of historical collections, and captive spawning trials were employed to target specific objectives for each species. In female Golden Topminnows, they appear to conserve the energy invested towards reproduction, as the yolk volume of embryos and egg gram-1 fecundity did not differ between female size classes. This nondifferentiated reproductive investment, coupled with decreased survival to hatch and smaller total length of larvae at hatch indicate stocking greater quantities of small or medium Golden Topminnows may increase production. Improved incubation methods could prevent potentially hypoxic conditions that may have led to inhibited embryonic development observed in the current study. Historical collections of Bluenose Shiners displayed distinct sexual dimorphism, especially in anal and dorsal fin lengths when their total length exceeds 45 mm. Results of gonadosomatic index and gonad histology analyses indicated a peak in maturity and supposed spawning between mid-May and early-June. Captive spawning of Bluenose Shiners was unsuccessful using natural environmental cues and/or hormone injections. However, the methods employed herein can guide future attempts, as temperature and photoperiod were likely successful at inducing gonadal maturation, but improper timing or presentation of nest-associate cues for gamete release may have led to the unsuccessful attempts in the current study. Golden Topminnows require further examination of stocking density impacts on egg production and larval survival, while Bluenose Shiners should be further used in captive spawning studies to determine what cue of their nest-associate is necessary to induce spawning.

Committee Chair

Green, Christopher C

DOI

10.31390/gradschool_theses.4941

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