End of the Summer

Unfortunately all summers must end, and so it is this year as well. We are wrapping up our fieldwork and focusing on the lab component. Below are a number of pictures from this summer that we had not posted yet.

Above is a damselfly perched on a leaf. Damselflies have four large wings that fold across the back. These are one of the most primitive aquatic insect groups (mayflies and dragonflies being the others). This individual was from Annsville Creek.

Another species of damselfly. All damselflies hunt on the wing capturing any small insects they can, they often then eat the prey on the wing while looking for another target.

This waterfall is a natural falls present on the Kaaterskill Creek outside of Catskill, NY. Sea lampreys are actually able to pass this barrier and spawn upstream.

This is a megalopteran, a different species, and likely a different genus (probably Sialis sp.), than the one we captured at the Black Creek. This is an adult which was out looking for a mate.

Above are black fly larvae (Simulidae) that we collected during out work. These are the larvae which are filter feeders, and also good indicators of high water quality. They secure themselves with silk threads to the end of rocks and are present in the fastest flowing sections of the water.

We found lots of lampreys in this stream under I-87. You never know what you maybe driving over top of when you are in the car.

This is a mummichog (Fundulus heteroclitus) we captured in the Muitzes Kill. This is a male, if his fins were better exposed you would see that they are actually fairly colorful.

Natural falls located at High Falls, NY. These are the lower of the two falls, with a dam at the top of the highest falls. In the spring time sea lamprey adults are regularly recorded from immediately below these falls.

An ammocoete from immediately downstream of the falls pictured above. This animal (based on the other animals we found there) was probably 3-5 years old. The nametag it had said "Bob".

Me standing sheepishly next to a rock at High Falls that was recently relocated by hurricane Sandy. The water level after the hurricane was still another 50 feet higher than me.

Looking out onto the Hudson River from the Sawkill at Bard College. The green mat is actually an invasive plant (water chestnut, Trapa natans) that has become quite a problem in the Hudson River. However, the scenery is still gorgeous.

I will continue to post on this blog about sea lamprey, although we may now expand our coverage to more than the Hudson River!

Return to Lowland Town Park (Cedar Pond Brook Creek)

During this summer I have been working under two grants (one through the Sussman Foundation and the other through the Hudson River Foundation). Both grants are interested in identifying the location of sea lamprey in the Hudson River and the capture of ammocoetes as vouchers for further research. However, the Polgar fellowship also includes a stable isotope component. I will need to write a separate entry to describe stable isotopes for those interested but we returned to Lowland Town Park to collect our samples for that portion of the fellowship. Last time we were in the park (July) we did not see any young of year lamprey (we arrived too soon) but we did find lots of them this time!

We also collected numerous stable isotope samples for analysis this fall when we return and process them at the lab first. Here is a picture of me returning with a terrestrial soil surface sample which we plan to analyze.

This creek is generally in very good condition with very complex habitat and large areas for the stream to meander. Streams need to move freely to behave naturally. Water is always eroding and access to flat areas around the river (called the floodplain) allow the water to disapate its energy and erode more naturally. This reduces the problem of flash flooding during storms and helps to create a more natural environment. Although rivers are marked on maps with very clear lines, natural rivers actually move quite often and make new paths for themselves (look on Google Earth to see if a local river looks the same as when you visit it today). Moving property away from the edge of a river and allowing it to snake around is important for healthy streams. Fallen logs, dams from debris, and exposed roots are all normal in natural streams. Notice below in the right of the picture the dried stones with vegetation  growing on them. This is actually part of the stream bottom during high flow events, and helps get the water downstream without damaging the forest around it.

Streams (especially in areas where people have lived for long periods) are often forced into narrow paths that are prone to flooding and large scale erosion. If you own property near a stream consider allowing the edge of the stream to grow wild in as many areas as possible to help improve your stream's health. The lamprey will thank you.

The sites we visited are downstream from a park and we did find some basketballs and beach balls trapped in a log jam. This one was returned to the park in need of air, but otherwise fine. On my back is the unit we use to cause ammocoetes to emerge from the substrate. The paddle is used to control the unit and catch the ammocoetes when they emerge.

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.

Black Creek

Last week, before we returned home when rain threatened, we also visited the Black Creek to look for lamprey. The Black Creek is a beautiful stream whose lower portions are largely protected wooded areas. In the spring visitors can still see alewife runs returning to spawn. Often times other species follow them, and you may also see large stripped bass resting in small pools and feeding on the alewife.

Sea lamprey have been captured here once before and we initially found conditions which looked favorable to sea lamprey (sandy bottom, clear water, low flow areas, diverse invertebrate community). However, after looking for some time we did not find lamprey of any kind. We did find a dead male blue crab (blue crab are actually common in the Hudson River, even in freshwater areas).

We also found the largest Hellgrammite I have ever run across. These insects are also called dobonsonflies and spend long periods as aquatic larvae (sometimes more than 3 years) feeding on other aquatic animals before emerging to pupate into the adult. The adults live for less than a month and look for a mate before dying. What you cannot see well in the picture are the gills which are all along the abdomen of this larvae. When removed from the water they cling to the abdomen and are difficult to see. This is a very low diversity group (especially in the Northeast) and this animal could be identified to genus on sight, it was a Corydalus spp.

Hellgrammites are indicators of high water quality often. Check your local streams by lifting rocks or kick netting to see if you have any. Be careful, although they rarely do, they are capable of a powerful bite which can hurt.

Cedar Pond Brook (Lowland Town Park)

We sampled in Cedar Pond Brook in Stony Point at Lowland Town Park on Monday.

There we found a wide array of invertebrates including some of the largest stoneflies I have ever seen. These stoneflies were Perlidae, and appeared to be Agnetina (although it would be best to see them under a scope to be sure). Stoneflies are considered good indicators of water quality, because they are often sensitive to pollution or sedimentation. After we finished with the invertebrate surveys we looked for lampreys and found an ammocoete within the park in less than 10 minutes!

Sea lamprey are known from this river (link) but their extent and distribution is largely unknown. In addition, we also found generous amounts of trash (usually aluminum cans). Please do not treat streams and rivers as disposal sites. High quality habitats are rare, and they could be in your backyard, even in places that you may visit daily! We continue on, and hope to find lamprey at one more site this week. More updates if we succeed or fail, and more pictures to come.

Stockport Creek

Sorry for the long delay in blog posts. A wedding and lots of sampling has gotten in the way of the blog. We returned to the Hudson River this week, and amongst other sites we visited Stockport Creek.

Stockport Creek has a large delta with numerous small braids and islands that greatly increase habitat complexity and offer excellent habitat to many species. Once you get over the rapids (pictured behind the bridge) you move from the tidal delta into a clear water stream that slowly meanders through the country. We initially sampled below the bridge at a sandbar created by fallen wood.

While working we found an empty mussel shell partly buried in the sediment. The shell belongs to a native species of mussel, which are often critically endangered. Our native freshwater mussels (not our zebra/quagga mussel invaders) are fascinating creatures that utilize fish hosts when they are larvae. As adults they live a sedentary life of filter feeding, but come spawning season they utilize lures to attract hosts for their larvae. You can start reading more about them here: http://www.fws.gov/midwest/endangered/clams/mussels.html

We moved upstream the following day to sample where the Stockport Creek branched into the Kinderhook and Claverack Creek. We looked for lampreys in both streams, but did not find any. However, both streams appeared to be in good health (especially at the Kinderhook). Water temperatures in both branches were too high for lamprey, but we were unable to sample higher up in both streams. Upon return we ran into an individual who worked on a dam in the Kinderhook and reported that sea lamprey were sometimes present there, but have not been around at least for a few years.

Maybe lamprey occasionally spawn in Kinderhook when they can get past the dam. Hopefully next week I will have more time to upload the blog and continue to add pictures. Until then if you have any reports of sea lamprey in the Hudson River please leave a comment where you think you saw them and approximately when. Thanks!

Continued work on the Roe-Jan

We continued our efforts on the Roe Jan on Tuesday, but we did not find any additional ammocoetes or any adult lampreys. We attempted to sample where lamprey have been found before but thunderstorms and tides made that impossible. However, we did sample upriver and did not find any more ammocoetes. In addition to ammocoetes we also collect other samples and data. Below is a picture of a kick sample preserved in alcohol.

Kick samples are exactly what they sound like. A sturdy net is placed along the stream bed and then the individual holding the net kicks and stamps materials just upstream of the net. Invertebrates kicked up or disturbed drift into the net and are captured there. Samples like these allow us to determine what invertebrates may be present, which gives us information on habitat quality and habitat types that maybe available. In addition, it helps to build our understanding of the community in which these organisms live. Although the sample looks like a mess of leaves and sand we then pick out the invertebrates and ID them to the lowest level possible (usually genus).

Determining the genus of an insect can take an exceedingly long time as there are many species in the Northeast alone. For instance, in North America there are ~650 dragonfly and damselfly species (~5,500 species worldwide) belonging to 12 genera, often distinguished by microscopic details. This is considered a very small group and relatively easy to differentiate. Other groups, like flies (with ~120,000 species worldwide), are so large keying an individual may take up to an hour or more.

How long will it take to key out the above individuals? Actually not long, both of these appear to be relatively common. The smaller is a badly damaged mayfly (Ephmeroptera) and the larger is likely a common stonefly (maybe Plecoptera:Perlidae:Agnetina) .

Roe-Jan

We are finally back out on the water after long delays from rain, travel, and rain again. This week we went to the Roeliff Jansen Kill to look for lamprey. The Roe-Jan (as it is affectionately known) is a cool water stream on the east shore of the Hudson, an hour south of Albany. It is unusual because it is one of the few cold water streams that enters the Hudson, and supports abundant trout fisheries. When we first arrived it was thundering loudly and rain was coming down. However, when the rain settled down we left the car and found out that the 17-year cicadas were out in force in the forest.

As soon as the rain stopped and the sun peeked through, the cicadas started singing again, LOUDLY. Felt like a late afternoon in August, not a Monday towards the end of June. They are beautifully colored with orange wings and bright red eyes. They were everywhere: flying from tree to tree, littering the ground, and flopping exhausted into the stream. We began our fieldwork shortly thereafter and just before nightfall we found this guy:

A sea lamprey ammocoete! Finally! An ammocoete is the larval stage of a sea lamprey. Like most other fish, lamprey have a larval stage which is quite different from the adult. However, unlike most fish lamprey larvae are the majority of the life cycle of the animal and spend their time buried in sediments in streams. Ammocoetes are often very rare (as any person who has looked for them can tell you) but they can be amazingly abundant (>100 animals per square meter). Although previous work has shown that lamprey are present in the Roe-Jan, this is the first record I know that comes from as far upriver as we found it.

We look forward to finding more lampreys this summer and will be sure to post more pictures as we do.

What are Migratory Fishes?

The work which I am conducting this summer is targeted at a migratory species (sea lamprey) on the eastern coast of North America. I will post more information on this fascinating fish in the future, but first we need to introduce a little jargon:

Diadromous fishes are any fish species that migrate between fresh and salt waters during the course of their life span. Often they migrate to find food and/or to breed.

However, scientists often use the words anadromous, catadromous, and amphidromous because these terms are applied to specific types of migratory patterns.

Anadromous species (of which the sea lamprey is one) lay eggs in freshwater, grow as larvae and juveniles there for some time, before returning to the ocean where the majority of their growth occurs. Note that ocean in this case can include any salt waters, from estuaries to open ocean. After growing in the oceans the adults return to spawn in freshwater. Some species are semelparous (meaning they only spawn once and then will die, as is the case with Pacific salmon), but iteroparous (species that spawn more than once) species are also common. Numerous species have individuals that maybe semelparous while others are iteroparous within the same population. In the Northeast we have many anadromous species including: American shad (Alosa sapidissima), alewife (Alosa pseudoharengus), blueback herring (Alosa aestivalis), striped bass (Morone saxatilis), Atlantic sturgeon (Acipenser oxyrinchus), sea lamprey (Petromyzon marinus), and Atlantic salmon (Salmo salar) amongst others (see http://www.umaine.edu/searunfish/fish/diadromous.htm for more information and excellent sources).

Figure 1. Anadromous life cycle of a Pacific salmon (Oncorhynchus spp.), a group of species native to the West Coast, but which demonstrates an identical life strategy to anadromous species on the East Coast. Image taken from http://www.marinwatersheds.org/salmonids.html.

Catadromous species lay their eggs in marine environments, the larvae drift or swim back to freshwater where they swim up rivers. They live in freshwater growing before ceasing to grow and returning to the ocean to spawn. After spawning all of the adults will die. In the Northeast we have only one species with this life history, the American eel (Anguilla rostrata). Click here to learn more about eels around the world from Nature.

Figure 2. Catadromous life cycle of the American eel (Anguilla rostrata). Eels around the world are under serious threat and  American eel is no different, you can read more about it at http://www.chesapeakebay.net/fieldguide/critter/american_eel. Image from http://bioweb.uwlax.edu/bio203/s2009/peaslee_alex/Anguilla_Japonica/Life_Cycle.html.

Amphidromous species have eggs laid in freshwater, migrate downstream to the ocean to grow, but then return to freshwater to continue growth. Once they are fully mature they will spawn (likely numerous times) in the rivers in which they reside. Note here the real difference between this and the other two prior strategies is that growth occurs both in the ocean and in freshwater. In the Northeast we have no amphidromous species, as this life history strategy is primarily limited to tropical and semitropical gobies.

Figure 3. Amphidromous life cycle, showing the days and approximate size for Sicydium punctatum, a Dominicana goby. Image take from Dr. Bell, http://www.ucs.mun.ca/~kbell/goby/Intro.html,see his webpage for further details.

The sea lamprey (the focus of my own research) is a semelparous anadromous species. However, unlike many anadromous species which spend more time in marine environments growing, sea lampreys spend the majority of their lives in freshwater growing very slowly as larvae (sometimes more than 17 years!) before entering the ocean and spending 1-3 years growing. They still do the majority of their growth in the ocean (>95%), even though they live for so long in freshwater.

Rained Out

Unfortunately the rain yesterday made water levels rise and sampling impossible in the Normans Kill where we wanted to go. Here's a picture of me looking forlornly at the Normans Kill, which the day before was no more than 65cm deep and easily wade-able. Whereas today I did not even bother to step off of the shore.

We went south and continued to survey streams to find locations we could sample in the future. We also stopped at the Vloman Kill where we ran into this species:

This is a banded killifish (Fundulus diaphanus), which are common in the Hudson River. We found this one while searching the mud flats at the Vloman Kill where it was likely looking for invertebrates to eat.

First week out sampling

We searched in the Poesten Kill and the Normans Kill. We did not find any lamprey today, and we were delayed by rain, but we did find many American eels (Anguilla rostrata)!

We caught this one and quickly took its picture before releasing it.

After we arrived at the Normans Kill we found longnose dace (Rhinichthys cataractae) and one more American eel (Anguilla rostrata).

Funding for Summer 2013

Stockport Creek

Funding from the Edna Bailey Sussman Foundation and the Hudson River Foundation has come through!
My wife and I are out looking for sea lamprey all over the Hudson River watershed. We also collect invertebrates and other data at each site.

So, if you are interested in lamprey, fish, or just beautiful views of the Hudson River stay tuned! We will post pictures, stories, and videos of the work from this summer.