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Biodiversity Collections (Texas Natural History Collections),
building LSF/PRC176 (campus mail R4000), 10100 Burnet Rd.
Austin, TX 78758-4445

American Eel

December 11, 2024, Filed Under: American Eel

wanted poster

Post a flier:

We are asking people to post the following “wanted poster” in work places and angler forums around the state (download printable pdf).


Funding provided by Texas Parks and Wildlife Department and the University of Texas’ Biodiversity Collections.

December 11, 2024, Filed Under: American Eel

email list

Gulf of Mexico eel email discussion list

In collaboration with Robby Maxwell of Louisiana Department of Wildlife and Fisheries, we created an email discussion list to facilitate discussions and collaborations among anyone studying (or simply interested in) American Eel in the Gulf of Mexico and its tributaries.

CLICK HERE to send an email that will automatically subscribe your email address to the list (“gom_eel”). If that fails for any reason try

  1. sending an email (from the address at which you want to receive postings to the list) with ‘subscribe gom_eel’ (without quotes) in the subject line to sympa@utlists.utexas.edu
  2. following instructions at https://utlists.utexas.edu/sympa/subscribe/gom_eel 
  3. emailing gom_eel-request@utlists.utexas.edu to request a subscription. 

December 11, 2024, Filed Under: American Eel

Eel updates

October 2022 – Final report delivered to TPWD (link coming soon, or contact us for report).

March 2022 – COVID slowed us down significantly, but our collaborators researching genetics and otolith microchemistry of eels should soon be filing their final reports with us, and we then will file our final report on statewide eel sampling with Texas Parks and Wildlife. At the same time, with that funded project is ending, we’ve put together a plan to start a barebones capture, mark, recapture project focused below Longhorn Dam in Austin and nearby Colorado River tributaries where it appears there are currently many small, recently recruited eels. Knowing of those opened doors to opportunities to study of eels in Texas in new ways that can reveal much more detail about how the species functions in Gulf of Mexico rivers and how important Gulf of Mexico rivers are in sustaining the species. A couple of great new volunteers joined our lab to help with that. Holland Austin is out most every weekend fishing for eels, and has provided lots of very important data on local populations that is an amazing complement to our couple of years looking statewide for them with TPWD. More recently, Aidan Mabey, with over a decade conducting research on American Eel in the very successful Hudson Bay glass and elver monitoring program, and doing K-12 outreach work on eels, moved to Austin and joined our team to help spearhead the local mark/recapture work that we hope will be up and rolling by late spring 2022. 

January 3, 2020 – The Atlantic published a great 15-minute video documentary on the elver fishery in Maine.

September 27, 2019 – Radiolab released a great podcast on eels.

September 17, 2019 – this project got some important publicity via a front page article in the Austin American Statesman newspaper.

May 13, 2019 – Our eel project’s going quite well, in large part due to our close collaboration with the Rivers Study group of Texas Parks and Wildlife (TPWD).

We slightly surpassed our goal of 100 tissue samples for genetics. All of Texas’ major river basins except the Neches and Trinity are represented and the tissues are all now with the doctoral student doing genetic analyses at Université Laval in Quebec. We know that at least Louisiana Department of Wildlife and Fisheries, colleagues in Costa Rica, and others in the Caribbean, have also contributed tissues to the same study. We extracted otoliths from all of our specimens for microchemistry (informative regarding timing of movements of individuals between salt- and freshwater) and ageing in Dr. Ben Walther’s lab at Texas A&M University Corpus Christi.

That sample size was attained by extensive sampling, often at night, that threw virtually every type of gear at them that we could muster. In wadeable areas, trot lines and backpack electrofishing were most productive, especially when deployed in the vicinity of rip-rap and below dams, and TPWD took good numbers via boat-based electrofishing in larger habitats. Sixteen (ranging from 16.7 – 78.4 cm Standard Length) were found when a pump maintenance project de-watered a sump in the outflow channel of a sewage treatment plant.

That diverse sample includes all size classes from a presumed elver (15.1 cm SL) to what we presumed likely to be a downstream-migrant adult found dead on a beach and salvaged after only partial scavenging by birds. We did not target leptocephali larvae, and efforts to get glass eels and elvers were taken on by our collaborators at TPWD, deploying eel mops and fyke nets at scattered sites along the coast. So far, this effort has not produced any glass eels or elvers, but mops are still being deployed. As far as we know, nobody has ever documented glass eels in TX.

Our efforts to increase awareness about the species and our need for specimens produced many more (including historic) records of occurrences. These came from anglers and other private individuals, and from other researchers who incidentally took them while sampling for other species.

We’ve had some interesting detours and spinoffs along the way that pique our curiosity, and we’re starting to explore them a bit:

The remarkable paucity of records of leptocephali from the Gulf got us thinking more about their voyage from the Sargasso Sea to Texas. We’re hoping oceanographers far more knowledgeable about ocean currents and their histories than us might provide some insights. We also know some researchers have figured out how to predict timing and magnitude of arrival of Sargassum spp. to Gulf Coast beaches, and that work might also prove relevant to eels. In any case, given the distance and obvious complexity of that journey from the Sargasso, we wouldn’t be surprised if leptocephali make it to the Gulf and Texas only relatively rarely and sporadically, and anything that might help us anticipate where and when to expect glass eels to be heading up Texas rivers would be most welcome. Currently, any attempts to get samples of glass eels along the Texas coast remain pretty much a “shot in the dark.” However, given the importance of glass eel monitoring for assessment of recruitment throughout the rest of the species’ range, figuring out how to find and quantify them as they enter Gulf rivers is likely to be key for long-term monitoring and determining the status of the species here as well.

Maybe related in some way to ocean currents, in contrast to the rich archaeological record of eels in Europe and the eastern US/Canada, we’ve discovered that there are apparently no records of the species in the relatively rich and well-studied Texas archaeological record. So, we’re talking to regional archaeologists and hoping to take a closer look at the archeological data for evidence of eels. Could it be that their arrival to the Gulf has been relatively recent, and perhaps related to a change in ocean circulation between the Sargasso, Caribbean, and Gulf?

December 11, 2024, Filed Under: American Eel

American Eel

The American Eel, Anguilla rostrata, is an amazing fish with a remarkable life history involving huge migrations. While widely distributed across most major river drainages of the Atlantic coast of the U.S. and Canada where it’s well studied, relatively little is known about the populations of drainages of the Gulf of Mexico and Caribbean.

We’ve been interested in, and learning more about eels in Texas (and elsewhere) for several years now, and have been funded by Texas Parks and Wildlife Department (TPWD) to study them across Texas. We have now given a number of presentations reporting our progress and trying to get more people involved and contributing data to this effort. Here are some links to those presentations:

  1. January 2023 update – Since what’s listed below, there’ve been more presentations, an exhibit on American Eel installed in the UT Life Science Library (Hendrickson, D. A., Casarez, M., Cohen, A. E., Chapman-Tripp, H., Maisano, J., Elmer, N., & Kennedy, A. (2021). A Case For Eels [Physical exhibit]. https://biodiversity.utexas.edu/news/features/case-eels), and we filed our final report with Texas Parks and Wildlife, Finally, late last year, the first specimens of American Eel glass eels ever collected in Texas were taken near the coast. We have yet to see the specimens, but the collectors are confident of their determination to this species.   
  2. In March 2018 Dean was a guest speaker for the Colorado River Alliance’s Barstow Speaker Series program.  The talk highlighted the species of the Colorado River with a special attention on American Eel and what is known of their distribution and status in Texas.  A published version of the talk can be found here and an archived video is on the Colorado River Alliance FB page here.
  3. In November 2017 Dean presented this talk to the Texas Commission on Environmental Quality’s 31st Annual SWQM (Surface Water Quality Monitoring) Workshop on November 8, 2017 in Bandera, Texas.
  4. In September 2016 Dean gave a keynote address at Barton Springs University, then in October presented an expanded version of the same talk to a meeting of the Austin Bastrop River Corridor Partnership. That Powerpoint (with content in notes fields as well as in slides themselves) is available via the link below.
  5. In January 2016 we presented  a paper reviewing what we knew about American Eel in Texas at the Texas Chapter of the American Fisheries Society. The data we were able to compile (included in the archived presentation) indicate that eels likely still occur in all Texas rivers, but there are very few specimens in collections, and almost none from which we could get tissues for genetics or otoliths. Then, another version of the talk was given in early 2017 at the annual meeting of the Southern Division of American Fisheries Society. 

Given that our core mission as a scientific collection is to collect and archive specimens and observations, we decided to invest some of our time in initiating a “grassroot” collaboration to acquire and share information and specimens. Texas Parks and Wildlife Department (TPWD) partnered with us by providing materials to build some eel mops that we distributed to volunteer samplers, and both we and TPWD have obtained new specimens from our own sampling efforts, as well as via legacy data. But more will be needed.

If you have observations to report, or specimens to provide, or know anyone who does, please help us compile and share that information. We will make any data received available online to all researchers via our Fishes of Texas website.

We welcome all interested in American Eel in the Gulf of Mexico and its tributaries to join our email discussion list.

eels_for_austin-bastrop_river_corridor_partnership_2.pptx19.22 MB

December 11, 2024, Filed Under: American Eel

contribute data & specimens

  • If you took and possess a photograph of an American Eel and know where and when (even if just approximate) it was seen, please submit that observation to our iNaturalist project. If you prefer not to post there, please use the form in the link in the bullet below, or send the image and collection details to fishesoftexas@gmail.com. Close-up photos of the head and lateral photograph of the whole animal will help with positive ID. 
  • Any evidence of any eel in Texas is important, no matter the quality of that evidence. If you have access to an image that is not necessarily yours, or know of an observation lacking a photo, or someone has simply mentioned catching an eel somewhere to you, etc., please use this data entry form to submit that observation.
  • If you have a specimen, please keep it alive or place it on ice and contact Melissa Casarez or Adam Cohen (Texas Natural History Collections) as soon as possible. We prefer, and can do more research with, live or fresh specimens (never exposed to formalin), however, we’d like the specimen regardless of its condition (formalin preserved, rotten, skeleton only, etc.). Every specimen is at least a scientifically defensible occurrence that can add understanding to distributions over time. We’ll arrange for transport and will formally deposit specimens into our research collection.
  • Please contact us (using any link above) prior to collecting if you are targeting American Eels or expect to be in an area where you might encounter them. We are hoping to get tissue samples that we can use for genetic and stable isotope analyses. If you are targeting eels we can provide special instructions, and loan you tissue collection supplies and preservatives in some instances. Here we provide a link to a map of locations  where we think there to be a higher probability of collecting eels (mostly streams just below dams).

Help us sample

 * Update (May 2021)– We have concluded the eel mop sampling portion of this study.  Thanks to all who have been involved in this effort and also to those who have reached out and expressed interest.

  • Deploy and monitor an eel mop:


To date there are no known observations of glass phase (“baby”) American Eels in Texas. We are seeking highly motivated people or groups with easy access to creeks and rivers, especially in mid- to lower-reaches of drainages, to assist us in efforts to capture immature American Eels as they make their migration into freshwaters. We have constructed eel mops (funded by TPWD) following the methods proven on the east coast to capture glass American Eels. If you would like to deploy one and check it regularly (daily would be ideal, weekly ok) we may be able to provide one to you or provide materials to construct one. Please contact us if you are interested. If you are selected for an eel mop we will arrange for transfer and provide detailed instructions. Be aware that deployment of an eel mop requires a valid TPWD scientific research permit that includes eel mops as an approved method. We can help anyone sincerely interested in this obtain such a permit. 

  • If you have a mop you can enter your mop data here.

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