On the Delaware River before the Fall

Fall is rapidly approaching and while I was out sampling this weekend I definitely saw that. The water is getting colder and the trees are changing color.

The water level is also extremely low (as is normal during this time of the year). Here is a picture of where I work. When the water levels go back up this rock bar will be returned to the stream.

A picture looking upstream partially underwater of the same area. The water is so green because it was very cloudy.

The new rip rap put in by the NYSDEC to provide parking. This is not actually good management unfortunately. The rocks will turn the stream into the other bank and cause the river to erode into the bank just in front of the bridge. Likely DOT will need to come out in the future.

 

A small dam just upstream. Behind the dam is a pool where I catch lampreys every month. They do appear to leave here with some regularity so it is not a complete barrier to their movement.

Just before I left I took a picture of the valley from the parking lot. Quite a scenic place.

Tagging American Brook Lamprey

I returned to Dyke Creek last Saturday with my wife so I could finish sampling in one day. We had to wake up early and we did not return home until almost midnight, but we did manage to finish the entire site. Unfortunately, we did not capture any transformers, but since Cait was with me there are pictures of me. We stopped taking pictures relatively soon after arriving as we were trying to get through samples as quickly as possible so we would finish before the sun went down.

This picture was taken just to the right of the first pool and looking downriver. The stream actually braids into two separate channels just above this point, so this is about half of the stream.

Route 417 as it passes over the site. We set up our first sample processing station just under neath. Cait moved it slightly so she could sit in the sun.

Working up an animal with the syringes used to inject the color in the foreground.

Brought a chair this time so I (or Cait) did not have to sit on the cold rocks. Temperatures started off in the 50's and rose into the high 60's low 70's by the end of the day. Water temps held steady around 58°F.

A nice picture, taken by Cait, from the shore.

Setting up the blocking net before starting to shock to prevent lampreys from escaping while I worked.

Pictures of me sampling further upriver. The pool here had quite a bit of algae growth so my ability to catch the lampreys here (where Brooker lives) was low. That is not a problem for the models I use, but means that the total number of animals we needed to work up on this sampling occasion was not as high as in the past.

I am trying to go out again this weekend. If I succeed I will update the blog again. Until next time, happy lamprey hunting.

Maine and the Delaware

Sorry for the long delay, but I was in the field almost continuously since Thursday. I visited my sites in the Delaware River before I headed all the way to Maine to do work with another researcher. Of course pictures were taken and lampreys were captured.

Lamprey having its weight taken after the length was measured.

 A bunch more lampreys and at the bottom a transformer. He was tagged but interestingly his body destroyed the tag. The scars are still present from where the tags were, but the colors are completely gone!

 I had help so there are even some pictures of me, here posed.

 Working up some lamprey on a gravel bar in the stream.

 Showing off one of the trophy ammocoetes while recording data and preparing to tag.

Last picture of me standing ready to go hunt for some lampreys with water for myself. When temperatures break 80F I can easily go through a gallon of water in a day, since I may have to stand still in the sun for 1-2 hours while collecting the ammocoetes. It's a good idea to know your biting flies so you can quickly decide if you need to kill or ignore the animal that just landed on your arm or face.


And now pictures from Maine. Last time I went I did not have a functioning camera. This time I had a camera (courtesy of my considerate in-laws) so I made sure to take lots of pictures.

Picture of one of the streams I worked at in Maine. This is a shallow stream (as you can see) but in the spring 100's of adults swim through here looking for a good place to make nest for their eggs.

And here are the nests of two lamprey pairs now 2 months after they were created. When the water was up the entire nests would have been covered. Now that the water has come down the very lower portion of the nests are exposed. The eggs have already hatched and the tiny ammocoetes (~8 mm long) have moved downstream to find a place to call their own for a few years.

Two pictures of areas where ammocoetes collect. In the top picture we found more than 40 animals, and in the bottom pool we only shocked a section but collected about 50 animals.

Here are some of the lampreys immediately after capture. Note that they are very small, the animals we found in Maine are frequently half the size of their compatriots in the Delaware River. This is not because of genetic differences between populations (lampreys do not return to a natal river, they only return to a river they consider suitable to spawn in), but is instead related to the length of the growing season. Numerous short growing seasons keep the animals small and encourage them to give up growing as soon as possible and try to make their living at sea on other animals. Look out for the very small animal towards the center, that animal is probably 2-3 months old and is the largest that animals from this year are at this time.

An underwater video of some of the fish that share the same habitat. See if you can spot some of the fish that Maine lists as "baitfish" here (link).