Today the lamprey become...ammocoetes

Some of the little lamprey are moving right along, today I found my first ammocoete.

Here you can see it looks like an actual fish now, there is a clear head and a tail. And for those of my students you can easily see three of the defining features of chordates here (post-anal tail, notochord, pharyngeal slits). Th tiny black dot is the eye, this is a fairly undeveloped eye mostly good at detecting light or dark, not for telling that a giant eye is looking at you through a microscope.

The gut is really dark in this photograph because it is still filled with yolk. As the animal finishes development the yolk will disappear and the gut will be ready for real food to start coming in.

Although you cannot see it in the picture, under the microscope it is easy to watch the little heart beating away.

A closer look...

More time permitted me to take some close up pictures of the eggs and the pro-larvae.

Here is how they all start, the grid is 1mm x 1mm. Inside of these tiny balls is a little bit of yolk and some cells which assemble and make an animal body.

And here is what they become a tiny pro-larvae, sitting quietly and continuing to develop.

Here is a much closer image, each of the grids is a 1mm x 1mm box, so you can tell this guy is small. The head is actually the smaller end pointed down. The little black dots are individual pigment cells.

Least brook lamprey and the meaning of (their) lives

The end of the spring is coming, and the summer will start soon. In the meantime, least brook lamprey in Maryland have been spawning. As part of my research, I have been keeping and studying adult least brook lamprey. As part of their day-to-day they went about spawning in the holding tanks, and we are now trying to raise the eggs and ultimately the larvae when they hatch out.

Excitingly, the eggs are becoming pro-larvae, and in a few weeks they will be larvae.
Here are some of the pro-larvae laying on the sediment and soon they will be able to burrow.

Don't believe me that those things are alive? Here they are wiggling.

And with a scale (pull tabs are 1 inch long, in case you were wondering)!

Hopefully, some of the work this summer will lend itself to more blog posts...we'll see.

Upcoming Lamprey Talk

I will be giving a lamprey talk at the upcoming Coastal & Estuarine Research Federation (November 5-9), you can see more about the organization and meeting here. I will upload the talk and of course post a link on the blog. The talk will focus on modeling lamprey life history or, more simply, predicting what animals should do during the lives to maximize the number of offspring they can produce.

In the meantime have a look at this picture, which is the material found within the gut of an ammocoete:

The pink is a stain to help us visualize the material, but the brown is the natural color. Ammocoetes ingest a lot of organic muck (often called detritus) but are able to extract nutrition from this material. There are also numerous algal cells in the detritus, which are also probably important to ammocoetes. The chocolate chips in the cookie dough, so to speak.

Lamprey Live Stream

In what may be a first for the internet, I am live streaming a talk about lamprey, based on some of the work reported on this blog. Head to https://www.youtube.com/watch?v=Zfk4xaGW6UY to have a look on Thursday, April 27, at 10 AM.

Summer 2016: The Whirlwind

I have not had a chance to update the blog in quite some time but I do now! My field work this summer was split between lamprey in the St. Lawrence region and back in the Genesee River.

The first images are from the Deer River in the St. Lawrence, truly a beautiful watershed just to the north of the Adirondack forest.

 Here is a log capturing sediments behind it which was home to many lampreys. The lower picture is from a slightly different angle.

One of the lampreys I captured at this site, an American brook lamprey, already quite large and probably going to spawn next year.

 

Other lampreys from a site further downriver. This is actually a different species of lamprey, a Northern brook lamprey. Although it looks very similar to the American brook lamprey as a larva you would easily be able to tell them apart as adults.

The lamprey immediately above cam from right under this bridge. In this river lamprey were everywhere where there was soft sediments to burrow into.

A view of another stream close by called Trout Brook. Trout brook is of course home to many trout, and receives some fishing, but it is also home to a very nice American brook lamprey population.

Here are just some of the "summer hogs" I collected from next to the culvert. They were measured and released.

A good example of growth at ages. Each one of the animals above is an average age for its size, the smallest lamprey above the "USA" at the top is from this year (age-0). You can age the others as you move down, the last animal is likely age-6. This is best guess work however, the lowest animal could be younger or older, it is very hard to know exactly how old it is.

And here is a good example of why it is hard to age lamprey by size. Both of these animals are from this year, but already you can see that there is a large difference in size.

Enough of the St. Lawrence lamprey, here are some pictures from the Genesee River.

A long-nose dace captured at the same time as the lamprey.

A really nice fantail darter also captured at the same site.

A bunch of fish, including the ones above, from the site I captured American brook lamprey at. This site is at Dyke Creek, and is where I did my mark-recapture work.

A perfect example of lamprey growth through time here again, but now with an animal called a transformer at the bottom. Animals at Dyke Creek are probably growing faster than at the St. Lawrence and you can see it takes a shorter amount of time to get big. The last animal will spawn this spring and then die.

A literal pile of small animals from this year's spawning run. Hopefully they will do well this winter and produce a strong year class.

A dragonfly perching while I worked. The color on it was truly stunning so I felt obligated to stop working long enough to take a picture.

Sea Lamprey Control

While I work on native populations of lamprey, invasive sea lamprey populations have caused a great deal of damage to Great Lakes fish stocks. As a result, large amounts of work go into controlling their populations by the Great Lakes Fishery Commission. If you are interested in learning more click this link to their YouTube video. In the meantime, here is a picture of an invasive albino sea lamprey ammocoete.