Catskill Creek

We visited Catskill Creek just outside the town of Catskill, NY to look for lamprey. Sea lamprey are known to spawn in the Catskill, and in June when we visited we saw a lone beaten up adult sea lamprey. Sea lamprey likely spawn there between May-June. If you would like to see sea lamprey spawning you will need a boat to travel up the Catskill to their spawning grounds.

While we were there this time we did not see any adults (as we would expect) but we did find lots of of small lamprey. These small lamprey are young of year (YOY), meaning that they are from this year's spawning.

One of the problems for lamprey researchers is estimating the age of the animals. We know these animals, which are also the smallest are indeed from this year. With that information we can make estimates of the speed at which they are growing and estimate how old an animal like the one below might be.

The YOY from the Catskill were 16-24 mm long, so we can say that they grow about 20 mm since June. That means they grow about 10 mm per month, so by November, when they stop growing, they should be 40-60 mm long. Which means the larger animal we see above is probably only a year or at most two years old. This is in line with how fast we think ammocoetes grow. Ammocoetes usually take anywhere from 3-7 years to reach maturity.