Dr. Claude Renaud, an expert on lampreys, set off in early September on a week-long collecting expedition in New York State. His goal? Collect specimens of the American Brook Lamprey, from areas where the species may have first been identified almost 170 years ago. Read more to see if his quest was successful.
For the past few years, I have been working on determining the number of species in the lamprey genus Lethenteron and establishing their evolutionary relationships. This genus is distributed over much of northern North America and Eurasia.
In 2012, with the help of Dr. Alexander Naseka of the Institute of Zoology, Russian Academy of Sciences in St. Petersburg and Noel Alfonso, a museum colleague, we collected two species from the Northwest Territories: the Alaskan Brook Lamprey, (Lethenteron alaskense) and the Arctic Lamprey (Lethenteron camtschaticum).
In order to complete the North American coverage of the genus, I needed to collect one more species: the American Brook Lamprey (Lethenteron appendix), described by James DeKay in 1842. In a taxonomic study, a scientist ideally examines material of a species from its type locality (i.e., the place from which the species was originally described) in order to compare it with other species.
While the Canadian Museum of Nature possesses thousands of specimens of American Brook lamprey, mostly from the Great Lakes region and the St. Lawrence River basin, we have none from the type locality, which DeKay generally gave as being the Hudson River in New York State. Now, the Hudson River is over 500-km long, so that’s a lot of river to cover!
Adding to the challenge is that DeKay did not mention whether he placed any of his lamprey specimens in a museum, nor could any be found in the museums along the east coast of the United States, where they would likely have been deposited (United States National Museum, Washington, DC; American Museum of Natural History, New York; New York State Museum, Albany). This meant that I needed to collect the material myself.
Consultation with Dr. Jeremy Wright, Curator of Fishes at the New York State Museum, as well as a search of the database of the New York State Department of Environmental Conservation indicated that the presence of American Brook Lamprey had been reported in only six tributaries to the Hudson River. These were distributed along a 230-km stretch of the Hudson between Troy in the north and the Bronx, New York City, in the south. The earliest collection made was in 1897 and the last reported was in 1974. In total, less than 50 individuals had been collected throughout the Hudson River basin during that time.
So, we had our work cut out for us! Noel and I left Ottawa early on September 5 and arrived at our first stop that afternoon: the New York State Museum fish collection in Troy. I was able to examine six spawning adults of American Brook Lamprey and confirm that the species was present in Tibbetts Brook, the Bronx in 1903.
The following morning we visited our first locality to search for the species, a place called Moordener Kill. Apparently, American Brook Lamprey was collected at this locality only once, in 1934.
“Kill” derives from the Dutch word for riverbed or water channel, and reflects the early colonisation of New York State by Dutch settlers. “Moordener” is Dutch for murderer and the creek name commemorates the fact that nine Dutch settlers were killed there in 1643.
In the end, we didn’t even try to sample at that locality because the habitat was inappropriate (i.e., a deep ditch with no water movement rather than a gently-flowing stream with a silty-sandy bottom). I suspect that the conditions might have been very different 80 years ago. We tried at a couple of places further downstream, but very little suitable habitat could be found and no lampreys were seen.
Our next stop was Roeliff Jansen Kill where we met Dr. Bob Schmidt, recently retired from Bard College, Massachusetts. Here we collected a dozen suitable lamprey larvae in about an hour. Unfortunately, field identication indicated that these were Sea Lamprey, Petromyzon marinus, and not American Brook Lamprey.
I will confirm this in our lab at the museum’s Natural Heritage Campus once the specimens are transferred from formalin to ethanol. Regardless of the final identification, it indicated to us that lampreys were present and that our technique worked.
What’s next? A future blog will reveal whether Claude and his team are successful in finding the American Brook Lamprey along the Hudson River.