Assessing the Distribution of Sea Lampreys (Petromyzon marinus) in the

Hudson River Watershed

Thomas M. Evans

SUNY College of Environmental Science and Forestry

Final Report to the Edna Bailey Sussman Foundation 2013

Background

Anadromous fishes, i.e., those species that spawn in freshwater but migrate to marine

ecosystems for the majority of their growth, are important members of many coastal ecosystems.

The historic abundance of anadromous fishes, combined with their ease of capture during

spawning migrations, has provided economic and social opportunities for numerous societies.

Early European settlers, familiar with migratory fishes, were still impressed by the abundance

and diversity of species that greeted them upon their arrival to North America. However, after

initially utilizing these vast resources, Europeans rapidly overexploited the fisheries, while

simultaneously limiting access to and destroying the freshwater habitats upon which anadromous

fishes depended.

The Hudson River estuary watershed (HRE) is a biologically diverse ecosystem which

currently contains nine anadromous fish species in its total of over 200 recorded species. The

anadromous fish community in the HRE has been, in general, well studied. However, research

efforts have not been evenly divided among all species, and gaps in the current understanding of

this important group remain. Within this group, sea lampreys (Petromyzon marinus) are the most

poorly studied member of the Hudson River anadromous fish community. Sea lampreys were

neglected because they were not considered economically or socially important in North

America, are often difficult to sample effectively, and perceptions about this species have been

dominated by research efforts on invasive populations – as well as public perception – in the

upper Great Lakes.

Sea lampreys belong to the most primitive group of vertebrate lineages (Order:

Cyclostomata), and employ an anadromous, semelparous (i.e., a species that spawns only once)

life history. However, unlike most other anadromous fishes, which spend a shorter time in fresh

than in the marine waters, sea lampreys spend protracted periods in fresh water (up to 17 years)

before a relatively brief time at sea (1-3 years). In addition, unlike many other anadromous fishes

in the Northeast where at least some adults spawn more than once, sea lampreys always perish

after a single spawning event. Because of the limited information available, there is no way to

know historical abundance, or which streams were utilized by sea lampreys prior to large scale

habitat alteration by European settlers. Even recent records of sea lampreys (i.e., those within the

last 100 years) are difficult to find, and are often anecdotal.

Although sea lampreys have not often been considered an important member of the

anadromous fish community, they may provide or have provided many of the same ecosystem

services as other anadromous species. Sea lamprey larvae spend long periods in freshwater and

contributions from the bodies of spent adults may have provided important food other animals.

In Maine, sea lamprey spawning coincides with first feeding of salmonid juveniles, and spent

adults, eggs, and embryos of sea lampreys may all provide important marine derived nutrients to

these young salmonids. In addition, sea lampreys continue to spawn after other anadromous

species during the spawning run; a sea lamprey adult was observed at a spawning site as late as

June 26th during the course of this study. Finally, sea lamprey body shape and swimming style

are unlike any other anadromous species, and they may prefer habitats not utilized by other

anadromous species. In the upper Great Lakes, where sea lampreys are invasive, barriers are

designed that specifically exploit their climbing style and exclude them from upstream reaches.

Therefore, this study addressed the need to establish the current distribution of sea

lampreys in the Hudson River. Knowledge of their location will help to both to understand how

these populations are responding to human alterations, what services they may be contributing,

and provide potential avenues for restoration. The work in the present study is also timely as

climate change further alters habitats and modifies the ranges of sea lampreys.

Sampling Sites

I sampled 22 tributaries of the Hudson River estuary below the Troy Dam for sea lampreys in

the summer of 2013 (Figure 1). The sites chosen were based upon New York State Department

of Environmental Conservation (NYSDEC) recommendations, as well as published, and

anecdotal reports of sea lampreys (Table 1). The sites sampled from north to south are as

follows: Poesten Kill, Normans Kill, Vloman Kill, Vlockie Kill, Muitzes Kill, Hannacroix Creek,

Coxsackie Creek, Stockport Creek, Catskill Creek, Roeliff Jansen Kill, Saw Kill, Rondout Creek,

Indian Kill, Black Creek, Quassaick Creek, Moodna Creek, Indian Brook, Annsville Creek,

Cedar Pond Brook, Minisceongo Creek, Furnace Brook, and the Croton River. Sites varied

widely in the predominant land use within their watershed, but sampling always occurred in

areas with fresh water, preferably above the head of tide. If access could only be found below

head of tide, sampling occurred there instead.

Methods

Surveys for Sea Lamprey

At 19 of these sites a full workup was performed, while at the remaining three only

sampling for sea lampreys was performed. A full workup included measuring local habitat

characteristics, physical and chemical sampling of the stream, a macroinvertebrate sample, and a

survey for sea lampreys at the site. In those sites where a full workup was not conducted,

conditions were determined to be extremely unlikely to support lampreys, usually because of

siltation or high water temperatures. However, to validate the expectation, sampling for lampreys

was conducted in the same manner as at all other sites. I also interviewed individuals who visited

the site during sampling. Any pertinent information they provided to the study was noted.

To determine the composition of the surface area of the sampled stream reach, a diagonal

transect across the stream from bank full to bank full was walked. At every step along the

transect two points were randomly selected and the bottom composition was determined

following the NYSDEC bottom composition scale for at least 100 points (NYSDEC 2009). If a

transect was too short to sample 100 points, a second transect was set and the process repeated.

Aquatic macroinvertebrate samples were collected by sampling the nearest riffle to the

sample site, walking along a 5 m diagonal transect, and kicking into a D-frame net. The entire

sample was immediately placed in 70% ethanol and stored at ambient temperature. Upon return

from the field invertebrates were picked from detrital material and classified.

To determine if sea lamprey were present at a site I used a backpack electrofisher

(Haltech, HT-2000) to electrofish for larval lampreys (Figure 2). A low shock (5 Hz, 150 V, 2:2

pulse pattern) was used to cause larval lampreys to emerge from the substrate. Animals that

emerged where captured before they could burrow. The weak pulsed electrical output

encouraged larval lampreys to emerge and attempt to burrow rapidly, in contrast to a continuous

pattern which generally caused them to forgo burrowing and attempt to escape the electric field

or remain burrowed. I electrofished for 15 minutes at each site, which allowed the sampling of

all habitats that appeared likely to support sea lampreys.

Completed Work

I sampled at 29 sites and collected lamprey at 6 locations, which have been stored and are

being prepared to be submitted to the New York Museum for archiving. One of the sites I

collected at (below High Falls, NY on the Rondout) was the first collection of sea lamprey on the

stream since 1934. I also worked through 20 invertebrate samples, identifying over 2000

individuals to genus and many more to order. I also had the opportunity at three sites (Catskill,

Cedar Pond Brook, Roeliff Jansen Kill) to traverse large sections of streams to get a better idea

of how sea lamprey are distributed within this habitat. The work completed to date defines the

distribution of sea lampreys in the Hudson River for the first time, and establishes a baseline for

future research. Finally, in addition to the results presented herein, work was also completed to

understand the food sources of larval lampreys through a grant from the Hudson River

Foundation.

Results

I found sea lampreys in four tributaries of the Hudson River: the 1) Roeliff Jansen Kill

(Columbia County, confluence at river km 178), the 2) Catskill (Greene County, river km 182),

3) Rondout Creek (Ulster County, river km 146), and 4) Cedar Pond Brook (Rockland County,

river km 63; Figure 1). Sea lampreys were not found in all rivers for which prior records of these

animals existed (Table 1).

Sea lamprey presence was not correlated with percent bottom cover (i.e., percent cover of

rock, rubble, gravel, sand, or silt), percentage of caddisflies, stoneflies, flies, or midges in the

invertebrate sample. Nor were they correlated with the species richness, the SDI, or the HBI for

invertebrate samples. Although it was not significant, sea lampreys were never found at sites that

did not also have stoneflies, and they were associated with sites that had a high percentage of

mayflies.

The average length of YOY larval lamprey was different between sites. The Roeliff

Jansen Kill YOY larval lamprey were larger ~10 mm larger (28.8±3.5 mm, SD) than larvae from

all other sites (18.8±2.6 mm, SD; Figure 3).

Present Findings

Sea lamprey presence/absence was associated with only a few of the metrics I collected.

These results are consistent with prior work that has found that sea lamprey distribution at the

site level difficult to predict from in-stream habitat data. However, to my knowledge this was the

first to attempt to link invertebrate and lamprey data. Sea lamprey larvae utilize habitat in the

hyporheic zone (i.e., area along the edge of the stream in which ground and surface waters mix)

potentially limiting the usefulness of gross site level characteristics to predict their distribution.

Subsurface flows, ground water temperature, and oxygen content may all play important roles,

but are difficult to measure and scale up.

The metrics collected on macroinvertebrates did not provide statistical measures to

determine if sea lampreys were present or not at a site. Nevertheless, macroinvertebrate

qualitative measures were still useful for evaluating a site’s suitability for sea lamprey. Sea

lampreys are intolerant of many types of pollution, as are many invertebrates, which are easier to

collect and more abundant. Habitats with a diverse invertebrate fauna, including stoneflies and

abundant mayflies, were always associated with sea lamprey. Sea lampreys were never found in

areas with low invertebrate diversity or where these two sensitive groups were absent. These

classifications (only to Order) are easy to do in the field in a matter of a few minutes and require

no special equipment to collect. These observations may help provide restoration efforts a way to

evaluate the feasibility of a site for supporting sea lampreys.

In an effort better to understand lamprey distribution, I electofished long lengths (>1 km)

of three streams to better understand how lampreys were distributed. Larval lampreys were often

located immediately downstream of habitat appropriate for adult spawning activities. Even

though appropriate habitat for larval lampreys was available at different locations in other sites in

the stream, the restriction of larval lamprey to only certain areas provides insights into their

colonization of new habitats.

Conclusions

The distribution of larval lampreys in the Hudson River is restricted to only a few

tributaries (i.e., Cedar Pond Brook, Catskill, Roeliff Jansen Kill, Rondout Creek). Worryingly, I

found sea lampreys in fewer locations in the Hudson River than have been reported in the past.

However, many of the reports are for adult animals, which were likely seeking suitable spawning

habitat and are not as sensitive as larvae. In at least one case (i.e., Stockport Creek), there

appears to be a true reduction in their range. Sea lampreys may be able to make rare successful

spawning events in this stream that produce larvae for extended periods, but attract easily visible

adults for long periods. The barriers to migration at Stockport Creek would be difficult for sea

lamprey to pass except during exceptionally high flow years. Animals unable to penetrate above

the falls and dams likely do not produce larvae, but any adult that made it upstream would have

excellent habitat available for spawning and the subsequent larvae.

Currently in the Hudson River the Catskill is the most important producer of sea lamprey,

and the Kaaterskill Creek (which is a tributary to the Catskill) is its most important tributary. The

Kaaterskill Creek has a long stretch of (>10 km) of unobstructed habitat appropriate for both sea

lamprey larvae and adults, making this unique to the Hudson River. The Roeliff Jansen Kill is

also an important tributary for sea lamprey in the Hudson River. Sea lampreys in the Roeliff

Jansen Kill may grow more quickly than at any of the other tributaries where they were captured

(Figure 3). More work is needed to determine if growth rates are actually higher throughout the

Roeliff, or if larval growth is more dependent on local conditions.

Sea lampreys prefer cool water, and as a result climate change is likely to restrict and

reduce sea lamprey numbers in the Hudson River. Although climate change is a threat to the

future of sea lamprey in the Hudson River, past human activities have also likely limited

populations through the construction of dams and pollution of stream waters. However, sea

lampreys in the Hudson River were likely never as abundant as other members of the migratory

fish community. The erosion of decaying dams and the removal of barriers to migration may

allow sea lampreys to exploit more habitats, potentially providing a buffer against climate

change impacts. Sea lampreys are an unusual member of the Hudson River that have been little

studied, but their uniqueness and importance as members of the anadromous fish community

make them deserving of more directed research efforts.

This study was expanded upon by a separate grant from the Hudson River Foundation

which allowed for work with stable isotopes to examine sea lamprey nutrition sources. The

addition of these data provided an opportunity to produce a manuscript for publication, which

will be submitted in 2014 to a peer-reviewed journal (Northeastern Naturalist). In addition, a

blog (www.lampreyhunter.blogspot.com) was created and regularly updated to provide an

opportunity to provide a permanent online record easily accessible to scientist and non-scientists

alike. Finally, I will submit an abstract to present this work at the AFS New York chapter

meeting in February 2014.

References

Bryan, M. B., D. Zalinski, K. B. Filcek, S. Libants, W. Li, and K. T. Scribner. 2005. Patterns of

invasion and colonization of the sea lamprey (Petromyzon marinus) in North America as

revealed by microsatellite genotypes. Molecular Ecology 14:3757-3773.

Greeley, J. R., and Greene, C. W. 1937. Fishes of the area with annotated list. A biological

survey of the lower Hudson watershed. New York State Conservation Department,

Supplement to the twenty-sixth annual report: Albany, NY.

New York State Department of Environmental Conservation. 2009. Standard operating

procedure: biological monitoring of surface waters in New York State. Operating

Procedure: Albany, NY.

New York State Department of Environmental Conservation. 2012a.

http://www.dos.ny.gov/communitieswaterfronts/consistency/Habitats/HudsonRiver/

Catskill_Creek_FINAL.pdf, (accessed October 19 2013)

New York State Department of Environmental Conservation. 2012b.

http://www.dos.ny.gov/communitieswaterfronts/consistency/Habitats/HudsonRiver/

Roeliff_Jansen_Kill_FINAL.pdf, (accessed October 20 2013)

Schmidt, R. E., and S. Cooper. 1996. A catalog of barriers to upstream movement of migratory

fishes in Hudson River tributaries. Report of Hudsonia Limited to the Hudson River

Foundation, New York.

Schmidt, R. E., and K. Limburg. 1989. Fishes spawning in non-tidal portions of Hudson River

tributaries. Final report to the Hudson River Foundation, New York, NY.

Smith, C. L. 1985. The inland fishes of New York State. New York State Department of

Environmental Conservation: Albany, NY.

Acknowledgements

I thank the Edna S. Bailey Sussman Foundation for funding and support of this project. I also

thank Kathy Hattala and Robert Adams for advice and guidance on selecting locations and

choosing streams to survey. In addition, thanks to all members of the NYSDEC who provided

help and reports of sea lamprey, and especially to those working on the Hudson River Almanac.

Thanks also to David Yozzo who allowed me to come field sampling with him and for providing

information. Special thanks to John Waldman, Robert Schmidt, and Erik Kiviat for their help this

summer. Thanks to Karin Limburg for her help and support throughout my work on this project,

and for reviewing and editing drafts. Finally, thanks to Caitlin Eger, my wife, for all her help and

for assisting in almost all of the field sampling for this project.

Table 1. Sites assessed for sea lamprey (Petromyzon marinus) in the Hudson River.

Stream Name County River km

Lamprey Reported Prior Source

Lamprey observed in this study

Annsville Creek Westchester 71 N NA N

Black Creek Ulster 135 Y Schmidt and Limburg 1989 NCatskill Creek Greene 182 Y Numerous Y

Cedar Pond Brook Rockland 63 Y www.piplon.org (2002) YCoxsackie Creek Greene 204 N NA N

Croton River Westchester 55 N NA N

Furnace Brook Westchester 63 N NA N

Hannacroix Creek Albany 212 Y Greeley 1934 NIndian Brook Putnam 85 N NA NIndian Kill Duchess 137 N NA N

Kaaterskill Creek Greene 182 Y Schmidt and Cooper 1996 Bryan et al 2005 Y

Moodna Creek Orange 92 N NA NMinisceongo

Creek Rockland 64 N NA N

Muitzes Kill Rensselaer 217 N NA NNormans Kill Albany 225 N NA N

Poesten Kill Rensselaer 241 Y New York Museum specimen (2007) N

Quassaick Creek Orange 100 Y NYS DEC specimen (2005) N

Roeliff Jansen Kill Columbia 178 Y Brussard et al 1981 Waldman 2006 Y

Rondout Creek Ulster 146 Y Greeley 1937 Hudson River Almanac Y

Saw Kill Dutchess 158 Y Smith 1985 N

Stockport Creek Columbia 195 Y Hudson River Almanac 2005 Interviewee N

Vlockie Kill Rensselaer 219 N NA NVloman Kill Albany 220 N NA N

Figure 1. Sampled study sites (23) for sea lamprey and the Hudson River watershed below the

Troy Dam. Sea lampreys were found at the Catskill, the Roeliff Jansen Kill, Rondout Creek, and

Cedar Pond Brook.

Figure 2. Larval lamprey captured from Rondout immediately below High Falls, NY. The scale

is in cm. Note that the smaller animal in panel B is likely from this year’s spawning.

A

B

010

2030

40

Stream Name

Tota

l Len

gth

(mm

)

Kaaterskill Creek Catskill Creek Rondout Creek Cedar Pond Brook Roeliff Jansen Kill

a a a a

b

Figure 3. Average size of young of year lamprey from all streams at which lamprey were

captured. The black line is the median and boxes are the second and third quartiles. Sites that are

different are marked by different letters.

Figure 4. Sampling equipment aboard an inflatable boat purchased to assist in sampling this

summer. This stream is the Catskill Creek above the confluence of the Catskill and Kaaterskill

Creek. Immediately behind the boat is a sandbar created by the downed trees which contained

numerous lampreys.

Figure 5. Searching for sea lampreys at Cedar Pond Brook in August of 2013.