One of the more enjoyable duties of being a biologist with Texas Parks and Wildlife is getting calls from people wanting to know about some “strange thing” they have caught or have seen. I enjoy these calls because it is usually about something I know a little about but not much, and it forces me to learn more about a species or group of animals that I probably wouldn’t think much about otherwise. Most people who call are avid outdoorsmen that know quite a bit about what is in the environment they spend time in, and what they may find strange or odd is most often something we biologists don’t come across very often either. I got a call about lampreys not too long ago from a gentleman that had caught a white bass (sand bass) that had a lamprey attached to it. As I mentioned earlier most people that spend a lot of time outdoors usually know what they’re dealing with and this fellow was no different. He knew that he had a lamprey but didn’t know that lampreys were suppose to be in Texas and to be honest I didn’t either. I knew there were freshwater species of lampreys but that was about all. So I went to find out what I could so I could answer this gentleman’s question and this is what I have learned.
There are 19 species of freshwater lampreys in North America. The Mississippi River system and the Atlantic and Pacific coasts have the most lamprey species. In Texas you can find the chestnut and southern brook lamprey and both can be found in our area (Sabine, Neches, and Trinity River drainages). Lampreys are primitive fish that look like eels and have no scales or bone, with their skeleton being made of cartilage like sharks. Lampreys spawn in rivers and streams by swimming upstream to lay their eggs in nests by creating a pit in the bottom. Juvenile lamprey larvae are called ammocetes and they burrow into the mud and will remain there for up to 8 years, feeding by filtering organisms from the water like oysters or clams do. The juveniles emerge and metamorphose into adults, which usually takes a few months. Depending on the species, freshwater lamprey adults will either not feed or will be parasitic and attach themselves to other fish. Lampreys that are not parasitic will spawn soon after metamorphosing into an adult. Lampreys die shortly after spawning.
The chestnut lamprey is what people will most often see in our area. They are native from Hudson Bay south to the Gulf coastal regions and west to the Trinity River drainage in East Texas. Chestnut lampreys are parasitic and adults will attach themselves to fish to feed. I found no reports while researching this article of these animals impacting fish populations so there appears to be no detrimental affects from these animals in our area. Since chestnut lampreys attach themselves to fish this is why they are the most commonly seen lamprey in our lakes and rivers. These animals spawn from spring into the early summer with several to many individuals spawning over a single nest. Females will lay about 10,000 to 20,000eggs and both the male and female die soon after spawning. Eggs are reported to hatch within 2 weeks and larvae will spend about a week in the nest before emerging and drifting downstream to where they will burrow and spend up to 7 years as an ammocete. The juvenile ammocetes are thought to emerge from the bottom and become adults in late summer through the early fall and will spend up to two years as parasitic feeding adults before they spawn and die. Adult chestnut lampreys are usually 8-13 inches long, have double pointed teeth, and are named after their coloration.
The southern brook lamprey is found from the lower Mississippi River, and Gulf Coastal drainages from Florida west to the San Jacinto River here in Texas. These animals do not feed as adults and spawn soon after they metamorphose from the juvenile ammocete stage into adults, which is complete by March. Female southern brook lampreys produce 800 to 2,500 eggs and both the male and female die soon after spawning. The larval ammocete stage of these animals is about 3-4 years where they will emerge to complete their life cycle. Southern brook lampreys are usually about 6-7 inches long and are brownish gray in color.
Dan Ashe is a fisheries biologist with Texas Parks and Wildlife Department. He has worked out of the Jasper, Texas field office since 2005 helping to manage east Texas reservoirs including Sam Rayburn and Toledo Bend. Dan has also worked as fisheries biologist in Puerto Rico, California, and Alaska but now calls Texas home.
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