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