NASH-DFWAPC San Marcos Collection Trip

In May, 2008 NASH (Nature Aquarium Society of Houston) and DFWAPC (Dallas- Ft. Worth Aquatic Plant Club) arranged a collection trip to San Marcos River, San Marcos, Texas. NASH was represented by Kevin, Thanh, Rick, his wife Melissa, myself and my better half Preetam. DFWAPC was represented by their president Nikolay and his wife. We started the drive from Houston to San Marcos at 5 am after meeting up Kevin and Than at Houston Aquarium Warehouse. Kevin was driving which was a good thing as both I and Thanh had slept just a few hours the night before. We arrived in San Marcos around 8:30 Am and met up with Nikolay and Casey Williams our guide from Texas State University.

San Marcos Springs Ecosystem is the second largest in Texas and along with the Comal Ecosystem has the greatest known diversity of organisms in an aquatic ecosystem in southwestern United States. The source of these springs is the Edwards Aquifers. There are quiet a few organisms that are endemic to these spring systems. This biological uniqueness is limited to first 4 miles of the San Marcos River and the Spring Lake. This ecosystem has a temperature of 72 degree F all year round. The water is extremely clear with visibility up to 20 feet underwater. This unique freshwater habitat is a home to several threatened and endangered species. These threatened and endangered species are not supposed to be collected for any reason, unless one has a permit from Texas Park and Wildlife Department and U.S Park and Wildlife Department.

Entering the protected area of the Aquarena Spring Lake through the Wetland Boardwalk the first aquatic plant we spotted was Hydrocotyle verticillata and Cabomba caroliniana. The water here was about 12” deep with a layer of organic sediments at the bottom. The banks of the lake were lined with Elephant Ears which is an introduced plant to this ecosystem. This specie has been considered responsible for displacing the now endangered San Marcos Gambusia (Gambusia goergei). As we proceeded on the boardwalk we startled some thing big in the water below by our movement. Peering down the sides of the boardwalk I was excited to see a large black shape about1.5 feet large dash towards the bank. My excitement soon faded as I realized it was large Tilapia. Tilapias were introduced in the Spring Lake to combat another introduced specie Hydrilla verticillata. The tilapias did not eat the hydrilla but established themselves in this ecosystem. Today both the Tilapia sp. and Hydrilla sp. are rampant in Spring Lake and have contributed to the destruction of the native species of plant and fish. This was the breeding season for tilapias and we spotted a large number of males which had dug round nests about 3feet across all over the shallows. We could spot large stands of Myriophyllum spicatum and Ludwigia repens growing here. Two other introduced wetland plants that have become a huge problem here are Eichhornia crassipes (water hyacinth) and Pistia stratiotes (water lettuce). Moving on we saw a lot of gambusia and flagfish. We could not exactly ID them as we were not supposed to catch anything here.

The day was turning out to be perfect for a collection trip. The temperature was staying around 78 degree F all morning. At about 10:30 am we proceeded to book our seats on the glass bottom boat. The water in this part of the lake looked turquoise blue like a coral reef. Huge strands of Cabomba caroliniana and Vallisneria americana created a beautiful underwater maze as colonies of soft coral would create on a coral reef. The glass bottom boat ride showed us how amazingly clear the water was even at 20 feet with lush green growth of aquatic plants even at the bottom of the lake. We also encountered specie of Fissiden in the eastern part of the lake. While waiting for our boat ride we found Hygrophila polysperma, Ceratopteris thalictroides, Cabomba caroliniana and Riccia fluitans growing in a quiet corner of the lake. The H. polysperma was some of the reddest I had ever seen. From the top this part of the lake looked like a nice aquascaped tank compleate with large Astyanax mexicanus (Mexican tetra) swimming in and out of the foliage. Most of the unique organisms found in this lake are bottom dwellers. We got a chance to check out some of these at the small aquarium maintained near the lake. The fountain darters (Etheostoma fonticola) were really interesting. These fish would have made a beautiful addition to a nano aquarium had they been not endangered.

Our next stop was going to be downstream from the lake on the San Marcos River. Here Casey showed us stands of Texas Wild Rice growing in the swift current of San Marcos River. Texas Wild Rice is another native species which is endangered due to destruction of its habitat. The water current in this part of the river was pretty swift, but we could still spot large patches of H. verticillata growing very close to the river bottom. As we proceeded further down the rivers bank we were amazed by the lush growth of Potamogeton illinoensis and H. polysperma covering the entire width of the river. We could not spot the river bottom for quiet some time after that. Here H. polysperma was growing both emersed as well as under water. We could also spot some C. thalictroides growing emersed along the bank.

Our last stop was going to be the spot where Kevin had seen some Cryptocoryne beckettii growing in shaded pools in the past. We were disappointed to find that spot closed to public due to some construction activity along that part of the river. It is alleged that C. beckettii was introduced here due to dumping by aquarists. We started our journey back to Houston from here. This was a well planned trip and all of us enjoyed our uneventful drive back.

Some more picture here:


2 Responses to “NASH-DFWAPC San Marcos Collection Trip”

  1. […] able to ID them. Most probably the red plant is Hygro polysperma. You should also check this out.…llection-trip/ Thanks Bhushan __________________ Checkout my blog […]

  2. […] of a collection trip to the same river. I too would love to get a bag if you are up for a trade. NASH-DFWAPC San Marcos Collection Trip AquaMusing __________________ Harry Witmore Cloud Jungle […]

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