This study examines the reproductive biology and age structure of Pterygoplichthys armored catfish in Landa Lake, New Braunfels TX. The objectives are to determine when they spawn, evaluate fecundity, determine age by examining otoliths, and compare findings to other studies. Armored catfish were collected monthly from April 2013 to December 2014. Gonads were examined to study reproduction, and otoliths were extracted and examined under a microscope to determine age. The data collected on reproduction and age will be compared to previous studies on armored catfish in the southern US to help understand the impacts and expansion of these invasive species.

1. Reproductive biology and age structure of Pterygoplichthys armored catfish in
Landa Lake, New Braunfels TX
Luci Cook-Hildreth1 and Heather L. Prestridge2
1Inland Fisheries, Texas Parks and Wildlife Department Austin, TX, 2Biodiversity Research and Teaching Collections, Department of Wildlife and Fisheries Sciences, Texas A&M University, College Station, TX
Predicted Outcomes
Mean fecundity and fecundity range of
Pterygoplichthys in Landa Lake will be compared to
fecundity data for similar species in their native environments
of South America and to data collected from similar studies in
the US. We anticipate the fecundity values to be similar to
ones assessed for armored catfish in South America based
on findings from Cook-Hildreth et al 2009 and Gibbs et al
2013.
Based on previous information for Hypostomus and
Pterygoplichthys catfish collected in North American spring
fed ecosystems we anticipate seeing a brief period of
reproductive inactivity in the winter months (Oct – Dec).
However, due to consistent temperatures in the spring fed
ecosystems where armored catfish have been collected, a
year-round spawning trend could be replacing typical
seasonal spawning regimes that have been recorded for
populations of armored catfish in South America.
Otolith data collected from the Landa Lake
Pterygoplichthys catfish will be compiled with length, weight
and sex information recorded at the time of fish collection
and will yield insight on longevity, mortality, and age at
sexual maturity. This data will be compared to data reported
for the Volusia Blue Springs, FL population of
Pterygoplichthys where Gibbs et all 2013 determined an
approximate life span of 5 years with sexual maturity at 2
years of age. Specimens deposited at the Biodiversity
Research and Teaching Collections including genetic
material, otoliths, and voucher specimens will be made
available for future studies.
Acknowledgments
Special thanks to Eric Munscher and the collection biologists at SWCA
for their efforts in collecting the armored catfish in Landa Lake for this
project. Much thanks to Heather Prestridge and Dr. Kevin Conway with
Texas A&M’s Biodiversity Research and Teaching Collections for prep
and storage of specimens , otolith extractions and processing.
Introduction
There are over 700 species of armored catfish in the
Loricariidae family which are native to South America. Due
to popularity in the aquarium trade a few of the hardier
genera of this family have been imported to many other
countries, including the United States, where they have been
released or escaped into new habitats. Established
populations of armored catfish were first reported in Texas in
the 1950’s in the San Antonio River. The San Marcos and
Comal Rivers in Central Texas now have sustainable
populations of Pterygoplichthys and Hypostomus armored
catfish.
Established populations of armored catfish in new
habitats have caused serious problems including increased
siltation and river bank destabilization due to burrowing fish
and nesting colonies. In addition to degrading the physical
environment in which they establish, armored catfish can
have many negative effects on the native fauna and flora of
fragile ecosystems.
Armored catfish colonies living in imperiled ecosystems
can pose a considerable problem for native threatened and
endangered fish and plant species through dietary overlap,
incidental egg predation, and habitat degradation. The
armored catfish populations in the Comal and San Marcos
Rivers are likely negatively impacting threatened and
endangered species such as the Comal Springs riffle beetle,
fountain darter, and Peck’s cave amphipod.
Understanding how and when armored catfish
reproduce, fecundity, age at sexual maturity and growth rates
would be beneficial to predict the timing of armored catfish
expansion into new ecosystems and continued impacts in
current ecosystems.
Pterygoplichthys specimen from Landa Lake after otoliths extraction.
Objectives
• Discern time of year that the population of Pterygoplichthys in Landa Lake are most likely to spawn.
• Evaluate the fecundity of the Pterygoplichthys population in Landa Lake.
• Determine age of Pterygoplichthys collected from Landa Lake via lapillus otolith removal and processing
• Calculate the relationships between age, length and weight of the Landa Lake Pterygoplichthys population.
• Compare findings for reproductive biology and population age structure for the Pterygoplichthys in Landa Lake to
similar studies for established armored catfish populations elsewhere in the southern United States.
• Create a voucher collection including whole bodies, otoliths and genetic material that is available for continued
study.
Methods
Location and Collection:
• Landa Lake is connected to the Comal River and is located in New Braunfels TX.
• The Comal River and Landa Lake are a spring fed system with less then 1 degree Centigrade variation in
temperature year round.
• Six to 15 Pterygoplichthys will be collected monthly from Landa Lake by biologists with the SWCA Environmental
Consulting Firm from April 2013 to December 2014
Reproduction:
• Total length, and body weight of each fish will be recorded prior to dissection and gonad removal.
• Gonads will be removed, weighed and preserved in 10% buffered formalin.
• Gonadosomatic index, stage of ovarian development, and number of oocytes will be recorded for each fish.
Ageing:
• Lapillus otolith deposits will be extracted from the Pterygoplichthys skulls, mounted on a slide and examined as
sagittal sections through a light microscope to determine age of the fish.
Comparison:
• The data collected on reproductive biology for Pterygoplichthys will be compared to data collected for Hypostomus
armored catfish living in the San Marcos River from 2005 and to similar studies on Pterygoplichthys armored
catfish in the US.
• Age data will be compared to findings from Gibbs et al 2013 for Pterygoplichthys living in Volusia Blue Springs, FL.
Ripe Pterygoplichthys ovaries collected in 2013
Literature Cited
Cook-Hildreth, S.L. 2009. Exotic armored catfishes in Texas:
reproductive biology and effects of foraging on egg survival on
native fishes (Etheostoma fonticola, endangered and Dionda
diaboli, threatened). Master of Science, Texas State University, San
Marcos.
Gibbs, M.A., B.N. Kurth, and C.D. Bridges. 2013. Age and growth of
the loricariid catfish Pterygoplichthys disjunctivus in Volusia Blue
Spring, Florida, U.S.A. Aquatic Invasions 8(1):207-218.
Location at Landa Lake where many of the armored cat fish have been collected
Nest holes likely made by armored catfish in the San Marcos River, TX
USGS and museum records of Loricariid distribution in Texas
Lapillus otolith of Pterygoplichthys from Landa Lake