A hand holding a fine net filled with gravel and sand. A small, orange Peck’s Cave amphipod is on the net being pushed up by a finger, no larger than a grain of rice.
The shrimp-like Peck’s Cave amphipod (Stygobromus pecki) is a subterranean aquatic crustacean species in the family Crangonyctidae. They are largely found in groundwater springs, upwellings and seeps exclusively in the Edwards Aquifer, more specifically in Comal Springs, Landa Park, Hueco Park, and near Panther Canyon in New Braunfels, Texas. They are most commonly found in ‘cave-like’ spring openings under rocks (Holsinger, 1967). Peck’s Cave amphipods are very small and grow to a maximum length of 10.5 millimeters (0.41 in). They lack eyes and their body is mostly clear but can have an orange hue due to their diet, much like all other species in the Stygobromus genus (Blake & Everett, 2017). Because this animal is an amphipod, it has five pairs of legs, two pairs of antennae and a long, curved body. This species is endangered, meaning that it is at high risk of becoming extinct, which is why the Edwards Aquifer Habitat Conservation Program aims to protect it and its habitat.
Edwards Aquifer Habitat Conservation Program (EAHCP)
The Peck’s Cave amphipod was listed as endangered in 1997 (USFWS). The Peck’s Cave amphipod is endangered due to its limited range and vulnerability to impacts from increased pumping of the aquifer, extreme drought, and pollution. The EAHCP works to protect and assess the health of the Peck’s Cave amphipod through various measures that include springflow protection, habitat restoration, and monitoring.
Habitat
In the photo there is an USFWS scientist under water in a wetsuit and snorkel gear sifting through gravel and stones with a small, fine white net, looking for Peck's Cave Amphipods (PCAs).
Peck’s Cave amphipods (PCA) are currently found in and near Comal Springs, Landa Park, Hueco Park, and Panther Canyon in New Braunfels, Texas. They inhabit the parts of these waters that have upwellings, or natural springs, presumably because there is good springflow in these areas along with an abundance of prey being introduced and stirred around.
A picture of the Comal river floor with cobble and stones moved back showing fine gravel and sand underneath where small springs are bubbling up aquifer water.
These amphipods like to dwell underneath large stones and then further under the gravel and sand; their homes possess cave-like qualities, hence their name. In 2016, researchers found that these creatures exhibit light sensitivity, which suggests that they rarely, if ever, leave their subterranean habitat (Gibson, 2016) . Not much is known about the PCA diet, but researchers have found that one source of nutrients comes from ostracods, the seed shrimp, that attach to leaves (Kosnicki, Ely & Eric Julius, 2019).
Long-Term Biological Goals
The long-term biological goals are defined in the EAHCP to prolong the health and livelihood of the covered species. For the Peck’s Cave amphipod, their goals focus on maintaining optimal springflow levels and water quality standards. For example, measured water quality constituents cannot exceed a 10% deviation from historically recorded water quality conditions (long-term average) in order to prevent negative long-term impacts on the species.
Monitoring
Picture of an USFWS scientist in snorkel gear and a wetsuit holding a collection jar that contains water, mesh, gravel and collected PCA. The container is being held over a small boat that holds all the necessary equipment for the scientists including nets and containers.
This photo depicts a large, clear pipette, with measurements along its length, and a finger blocking the end hole. Inside the pipette holds spring water with one rust-orange PCA inside the size of a grain of rice. The pipette is being held over a white bin.
In the picture is an USFWS scientist in snorkel gear and a wetsuit holding a blue, fine mesh net that has gravel and sand inside of it. The scientist is looking for rust red PCA among the contents of the net.
This is a picture of a zoomed-in view of a clear collection container. Inside there is white mesh, spring water, dark stones and wood pieces, and very small PCAs about the size of a grain of rice.
In this picture is an USFWS scientist in a wetsuit holding out a clear collection container with the contents of water, mesh, and PCAs.
EAHCP contractors collect biological monitoring data on an annual and seasonal basis to assess habitat conditions. PCA are sampled and counted in the Comal Springs system. Water quantity levels are measured through index wells, such as Bexar J-17 in San Antonio, TX and Uvalde J-27 in Uvalde, TX that continuously monitor Edwards Aquifer water levels and USGS stations in Comal and San Marcos monitor spring flow. Water quality data are continuously measured at stations in Comal and San Marcos and grab samples are collected at monitoring wells by EAA staff.
EAHCP Refugia
This is a picture of the inside of a refugia housing container for the Peck’s Cave amphipod. There is piping (about an inch in circumference) along the edge and in the middle of the container that serve as filtering and mock-spring flow systems. There are also 2 baseball-sized stones, brown leaves and white mesh atop it all, covering the entire bottom, and clear water in the container.
This is an inside look on a refugia housing container for the Peck's Cave amphipod. It includes leaves, filtering systems, rocks and mesh.
The purpose of the EAHCP Refugia Program is to ensure survival of the covered species during catastrophic events such as extreme drought or a chemical spill. In partnership with the USFWS, the EAHCP has two off-site refugia centers in San Marcos and Uvalde. USFWS staff collect the species, research their life history, and refine species’ propagation methodologies while they are in captivity. Results from this long-term program help enhance our knowledge and understanding of these unique species.
If you live in Central Texas, water conservation is crucial to saving this endangered species. You can help maintain their habitat by properly disposing of hazardous products to keep them from entering the aquifer and contaminating the water supply. When visiting Comal or San Marcos Springs, it is important to be mindful of the species environment, limit disturbance, and dispose of trash properly. Below are some additional tips you can do to help protect their habitat.
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There is a gathering of about 15 people with large digging equipment, such as shovels and pickaxes, and small potted trees. Some of the volunteers have EAHCP shirts on.
Two large, black plastic barrels connected to each other with 2-inch circumference black piping. One barrel is underneath a house's rain drain directed so that rainwater can flow into the barrel.
Medical Disposal
Flushing unused prescription medications can pollute water and impact the hormones of local aquatic wildlife. Walgreens and MedDropSA provide free disposal of prescription pills and liquids.
In the picture is a metal bin with the label “Safe Medication Disposal: Place unwanted medications here”. The bin is in the Walgreen’s pharmacy area next to a ‘drop off and pick up prescriptions’ desk.
Leaky Car Fluids
Get your vehicle checked for leaks to prevent oil and other fluids from contaminating the aquifer and nearby creeks and rivers.
Britton, David, et al. (2020). Increasing survival rate of Peck's Cave amphipod: 2020 Research Report for the Edwards Aquifer Authority. U.S. Fish and Wildlife Service, From the Edwards Aquifer Refugia Program. 1-22.
Gibson, Randy. (2016). Refugia Research: Development of Husbandry and Captive Propagation Techniques for Invertebrates Covered Under the Edwards Aquifer Habitat Conservation Plan. U.S. Fish and Wildlife Service, Prepared for the Edwards Aquifer Authority. 1-37. Retrieved from: https://www.edwardsaquifer.org/wp-content/uploads/2019/02/TSU_USFWS_Refugium_2015_FINAL_VERSION1.pdf
Kosnicki, Ely & Eric Julius. (2019). Life History Aspects of Stygobromus pecki. BIO-WEST, Inc. Prepared for the Edwards Aquifer Authority. 1-74. Retrieved from: https://www.researchgate.net/publication/330345066_Life-History_Aspects_of_Stygobromus_pecki
