Title page for ETD etd-052599-174233


Type of Document Master's Thesis
Author Schmitz, Mark Harvey
URN etd-052599-174233
Title Comparative Growth of All-Female Versus Mixed Sex Yellow Perch (Perca flavescens) in Recirculating Aquaculture Systems
Degree Master of Science
Department Fisheries and Wildlife Sciences
Advisory Committee
Advisor Name Title
Libey, George S. Committee Chair
Hallerman, Eric M. Committee Member
Smith, Stephen A. Committee Member
Keywords
  • yellow perch
  • Perca flavescens
  • fish culture
Date of Defense 1999-05-20
Availability restricted
Abstract
Nine, production-scale, recirculating aquaculture systems were utilized to

compare the growth parameters between all-female and mixed sex yellow perch stocks.

Each system was stocked with 455 fish m-3 and contained one of three different biofilter

types: a rotating biological contactor, a trickling filter or a bead filter. The all-female

fingerlings (S1) used were originally derived from Lake Mendota, Wisconsin. The

mixed-sex fingerlings (S2) used were originally derived from Lake Erie. Temperature

and photoperiod (23oC, 16H-L) were maintained at levels for optimal growth.

Absolute growth rates ranged from 0.27-0.48 g/day. Mean final density within

treatments was 42.8 kg/m3 and ranged from 37.2-50.2 kg/m3. The main effect of stock

did not have a significant effect on growth (p > .1). All-female treatments exhibited more

uniform growth. The main effect of filter type did have a significant effect on fish

growth (p < .01), with fish in tanks containing trickling filters exhibiting significantly

higher growth. Total feed conversion averaged 1.61 across all treatments and ranged

from 1.38-1.78. S1 treatments consumed a significantly higher percent body weight per

day than S2 treatments (p < .05).

Analysis of PIT tagged individuals revealed that the mean relative growth rate

was significantly higher in S2 individuals (513.9%) compared to S1 individuals (315.3%:

p < .01). S2 females (597.8%) grew 1.9 times faster than S1 females (315.3%: p < .01).

Within S2 individuals, females (597.8%) grew 1.5 times faster than males (395.2%: p <

.05). For all individuals, 33.6% of the variation in final weight was explained by the

variation in initial weight. Differences in the geographic strain or culture history of these

stocks may have had a larger overall effect on growth than sexual classification (all-

female or mixed sex).

Dress percentage of skin-on butterfly fillets was examined in 20 individuals per

stock and in six groups of 20 individuals per stock. Within S2 individuals, 73.7% were

female. Mean fillet yield was significantly greater in S1 individuals (47.6%) compared to

S2 individuals (43.0%: p < .01). Mean GSI in S1 individuals (1.01%) was significantly

higher than S2 individuals (0.54%: p < .05). Within S2 individuals, mean GSI was

significantly higher in females (0.70%) when compared to males (0.08%: p < .05). Fillet

yield was significantly greater in S1 groups (47.2%) compared to S2 groups (44.9%: p <

.01). Within each stock fillet yield increased with size.

The difference in fillet yield demonstrated between these stocks may be a result of

differences in strain of origin. The identification of superior yellow perch strains or

strain crosses with regard to growth rate and fillet percentage is of considerable

importance to the industry.

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