February 15-18, 2009 Washington State Convention Center Seattle ...

EFFECTS OF PHEROMONAL STEROIDS OR PROSTAGLANDIN GIVEN TO FEMALE
CHANNEL CATFISH Ictalurus punctatus ON ATTRACTING MALE BLUE CATFISH Ictalurus
furcatus OR MALE CHANNEL CATFISH
Jason S. Broach*, Shelley E. England and Ronald P. Phelps
Department of Fisheries and Allied Aquaculture
Auburn University
Auburn, AL 36849 USA
jzb0007@auburn.edu
Hybrid catfish, female channel catfish (Ictalurus punctatus) X male blue catfish (Ictalurus furcatus), exhibit better traits for
commercial aquaculture such as faster growth, better feed conversion, increased disease tolerance, etc, than do channel catfish.
However, the shortage and inconsistency of seed production of these hybrids has hindered its adoption by the industry. Traditional
methods of spawning catfish such as open pond and pen spawning has had limited success with hybrid spawning due to
some type of behavioral or environmental inhibiting factor. One of the primary reasons thought to cause this low success is a
lack of the male blue’s interest and attraction to the female channel. This study was conducted to determine if a blue and channel
male’s attraction to channel females could be increased via pheromonal steroid injections of either 17α, 20β-dihydroxy-4-pregenene-3-one
(17,20β-P) or its glucorinated form (17,20β-P-Glucosiduronate), or prostaglandin F-2α (PGF-2α).
Two trials were conducted using blue and channel males with average weights of 8.2 ± 0.91 kg and 3.9 ± 0.92 kg respectfully,
stocked into two separate 644 m² ponds at 20 males per pond. In each trial, four sets of six channel females with an average
weight of 4.63 ± 1.0 kg were injected intraperitoneally with an ethanol solution containing either 0.0 mg/kg or 0.5 mg/kg of
one of the following: 17,20β-P; 17,20β-P-Glucosiduronate; or PGF-2α. Females were held separately in large traps constructed
from 121 L plastic barrels spaced 6.4 ± 0.65 m apart in the ponds for a total of 12 females per pond. Traps were checked at 6,
12, 24, 48, 72, and 96 hours post-injection, and the number of males caught per female recorded. Logistic regression analysis
was used to generate maximum likelihood estimates of a male being captured based upon male species, female strain, hormone
injected, and post-injection time.
Channel males were attracted to PGF-2α injected females on 22.9% of their given opportunities, and were attracted to control
females only 1.4% of the time. Blue males responded to 17,20β-P-Glucosiduronate and PGF-2α injected females 8.3% of their
given opportunities for each treatment, but were not attracted to the control females. Males were 9.8 times more likely to be
captured at 48 hours post-injection than at either 12 or 24 hours post-injection. There was significant variation in response
among individual fish. One PGF-2α injected female attracted 66.7% of the channel males trapped in that trial. Only 15% of blue
males used were attracted to channel females, but those blue males were attracted on multiple occasions. These results suggest
that PGF-2α injections into channel females may enhance a blue and channel male’s attraction to channel females.
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