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).

Genesee River

Sorry for the long time between posts. My older camera (which I got for free when I purchased my computer to enter college) got some grit in the camera motor and cannot extend the lens any longer. As a result it could not talk any pictures so I was hesitant to fill the blog with text about my work. As an early birthday present I received a more rugged Fuji camera, so today will be filled with images as well as some underwater footage! Please note I was working alone so these pictures/videos will not be great as I was trying to do two things at once and the sky was overcast so the light levels were pretty low.

 The above pic is a good size distribution of the ammocoetes I see at my site. Keep in mind these are American brook lamprey so ammocoetes can be quite large (approaching 25cm). The animal at the top is likely a two year old (sorry I captured no animals <2 years old at this pool). Bottom bar is in cm's, top two bars are in inches.

It must be August because some ammocoetes are already getting ready for spawning in the spring. The animal below is a "transformer". You can see the eye developing the head shape is changing and the body is very thick (from all the fat reserves). The animal above is a normal ammocoete. The lower animal will probably feed very little in the next 8 months and will travel upstream to spawn in March or April (whenever water temperatures are good for spawning). Here it is showing off the tag it received before it was released.

 Another similar picture of the same animals, with a little different lighting.

Don't let anyone ever tell you lampreys are not important for ecosystems. I captured all of these animals in an area of about 1m² of habitat.There were actually quite a few more this is just part of the first pass. The amount of biomass literally under your feet as you walk through a stream can be quite surprising! These are the fish in the sand, but think of all the invertebrates (insects, worms [of all kinds], leeches, etc.) that are also in these areas. Animals like these bioturbate, convert plant and detritus into animal biomass, and actually change the very chemistry of the world they live in.

Above is a picture of the electro shocker I currently use. Backpacks like these use a small battery and control the output to surprise and stun fish. The Smith-Root LR-24 allows me to use a low power shock to scare the lampreys out of the substrate. Once they emerge I switch to another high power setting to immobilize them briefly so I can collect them. The yellow paddle is the stock paddle provided by the company. The white paddle is unique to lamprey hunting and is a modification of the other end (normally a long bare metal wire) so I can shock and grab by myself. The battery in this picture is under the control pannel on the back and is covered by a plastic piece. The battery is unfortunately for me, Lead-Acetate, and weighs ~30 pounds. Having 30 pounds on your back is not that big a deal, but it sits low and it is much harder to walk in the slippery streams when your center of gravity is shifted back and behind you.

This is one of the coolest pictures I took while I was out. There is some debate about whether and how much ammocoetes get eaten. Well here is proof that even large ammocoetes are the target of predators. This animal apparently was lucky because all it did was lose almost all of its tail. Here the tail is slowly growing back, although that probably limits its ability to swim until it does.

A close up of the tail from the injured animal. I promise I had nothing to do with this. The animal was not even one of the one's I had tagged until yesterday.

Another recap from May 2014 quietly sitting in the same sheltered pool it was left in last time. Hopefully it remains so I can keep catching it and seeing how fast it is growing. At the rate it is going now it will be an adult in 2016 or maybe 2017.

Above is a video of some of the lampreys being placed under general anesthesia before I begin tagging them. The anesthesia is irritating to mucus membranes (which is basically the whole lamprey body) so they are swimming around trying to find a way out. After about 60 seconds things settle down and the animals go completely under after 3-4 minutes. By the time they wake up they have been tagged, weighed, and had their length measured.

Here is a video of me releasing my tagged lampreys into the pool in which they came from in the first place. The animals are very excited to get back into the sediment. You may notice a net on the edge of the pool. I use a net to keep animals from escaping as I capture other by surrounding the area I am working with a net. I leave it there until all the animals re-burrow.

Back on the Genesee River

I returned to the Genesee River with help on Friday of last week (July 11 2014) and we had great success. We tagged another 250 lampreys before releasing them!

Here's a picture of Justin DiRado tagging one of our animals. The scale the animal is weighed on is in the foreground.

An up close pic of the syringe with the dye used to tag the lampreys. On the animal in the picture you can already see the orange line that was drawn first.

A fully anesthetized lamprey ready to be measured. At this point it is more of a wet noodle than a lamprey.

A close up of the oral cavity of the ammocoete with the skin exstensions that cover the oral opening to strain out the larger particles and only allow small particles in to the gill area. This animal is upside down. The muscular portion at the bottom of the picture is the oral hood, it is used to help burrow.

One of the largest (>200 mm, or >8 inches) lampreys we collected during this trip. This animal was transforming into an adult and will breed this coming spring (Spring 2015) before dying.

A work up station where animals were brought before being processed. Justin and Chris Powers are in the picture. They don't look too busy, but we were just about to clean up and head home at this point.

We only recaptured 5 of the original released animals but one of them was Brooker! Here Brooker has its marks refreshed and is then ready to recover. It was released again so hopefully it will be captured a third time. Brooker did not move from where it was released last month and only grew 2 mm, but put on 0.5g. Neither of these sound like a lot, but Brooker only weighed 5.56g, so it put on ~10% of its body weight in a month!

Oquaga Creek

Just returned from another sampling trip, this on a tributary to the Delaware River. The Delaware River is special because it is the only river in the United States that does not have a dam on the  main stem. It runs free all the way to the ocean! As a result many migratory fish spawn throughout the Delaware River, including sea lamprey.

I sampled on the closest tributary to Route 17, which for the lamprey is literally their last stop. They cannot move further west on the Delaware. In days past when the Susquehanna was available to migratory fish lamprey likely drove up in huge numbers to spawn through the Susquehanna as well.

Picture looking downstream just after quite a bit of rain and from the bridge which crosses the stream here.

This is the fishing access point where I parked. The NYSDEC just (as in yesterday) cleared this area of brush. They probably did not realize they were making more lamprey habitat by exposing a bunch of loose sand which will now wash into the stream and create sand bars just in time for this year's lamprey to find a new home.

The stream was literally crawling with lamprey. This tiny bucket had 54 animals in it when I took this picture. You can see some are on top of the sand because there is no room for them to burrow. As soon as the picture was done I released them back home.

Here is one of the smaller animals I tagged. This animal was from this year's breeding adults most likely and is hoping to one day have a chance to spawn, but that is many years in the future (probably a decade or more). Meanwhile, he can wear this pretty fluorescent dye. The finger is for scale, I am not pointing an interesting site out to it.

Another small animal with even more tags. I abandoned this effort early on as tagging a small animal this much is very time consuming.

Finally, one last picture of the site looking upstream. I suspect if you could see them there would be more than 1000 lampreys in all the pictures of the site on this blog now. But we will have to wait to find out how close my guesstimate is to the real number until I re-sample.

Roe Jen

I did not expect to tag animals on the Roe Jen this summer, but after working at another site where I thought I could get access to plenty of lamprey and having no luck I went to the park in Germantown.

A picture of the Roe Jen looking downstream.

And another of the bridge that runs through the middle of the park. The picture is taken from the beach/mowed area that allows easy access to the Roe Jen.

This damselfly (Calopteryx sp., the dusky wing damselfly) was out looking for prey and a mate.

Two pools that both held lamprey. The top one had about 30-50 animals, while the bottom one had just a couple.

A bag of marked lamprey ready to return to the pool from which they were captured, fully recovered and aching to go free.

Two images, both of the same animal. Here the animal has been marked, measured for length and weight and is ready to recover before being released. It has four marks on the body. The one above the head helps me determine if my tags are not blurring or losing color. The other three give the animal its unique code.