Karin's fisheries research interests -- Hudson River

American shad - Much of my research on fish has been focused in the Hudson River estuary in eastern New York State.  I have studied the life history of American shad (Alosa sapidissima, pictured here), in particular its migratory behavior and how that affects its success.  This species of fish has been intensively fished since well before Henry Hudson first sighted Manhattan Island, and is still one of the key commercial fishery resources of eastern North America.  In fact, it belongs to a subfamily of herrings that is so popular that it even has its own "fan club," The Shad Foundation.  We held a highly successful conference titled "SHAD 2001: The Status and Conservation of Shads Worldwide" in Baltimore, Maryland in May 2001.  The proceedings were published as a book through the American Fisheries Society.

Sadly, American shad, like many other species, are in serious decline. Check out the Atlantic States Marine Fisheries Commission’s reports on this and other fishes.

MSc student Chris Nack is studying how different habitats affect the well-being and recruitment of larval shad. This work is getting the support of the NYSDEC and Riverkeeper (thanks!). Additionally we are looking at the role of predation on juveniles, because in some river systems it’s thought that striped bass suppress shad and river herring recruitment. We are mid-way in these projects, so stay tuned. 

River herring - Currently, there is great interest in blueback herring (Alosa aestivalis) and its congener species, the alewife (Alosa pseudoharengus). These two fish species together are referred to as river herring, even though they spend most of their adult life out at sea along the coasts (ironic, eh?). The Atlantic States Marine Fisheries Commission is currently assessing their status. But there is no doubt: they are in serious decline.

A couple of my doctoral students are currently working on these species. Rita Monteiro is studying how alewife recruitment is affected by urbanization processes, and Sara Turner is studying the chemistry of river herring otoliths (look here to learn about otoliths) to determine if they can be used as natural tags to track down and identify the provenance of marine bycatch.

A while ago, together with Nina Caraco from the Cary Institute of Ecosystem Studies, and Robert Schmidt from Simon's Rock College, I studied how the invasive species, the zebra mussel, altered the food webs of the Hudson that supported blueback herring, The blueback appears to be moving up into the Mohawk River, where it appears poised to invade Lake Ontario via the NYS Barge Canal.  An MPS student, Ian Blackburn, an undergrad, Paul Simonin, and I studied the population ecology of this species' range expansion potential, by looking at migration energetics, growth characteristics, and fecundity. 

Eels are among the coolest animals alive. Unfortunately, the ones that people like to eat (American eel, European eel, and Japanese eel) are…guess what…in serious decline. Len Machut (MSc SUNY ESF), Bob Schmidt, and I studied how eels use tributaries of the Hudson River. We found some of the highest densities ever reported, in the lower reaches of tributaries. We also found that barriers – especially unnatural ones (dams) – play a big role in limiting the penetration of tribs by eels.

Striped bass - I've also studied the ecology of the larvae of two other important species in the Hudson -- striped bass (Morone saxatilis) and white perch (M. americana).  Stripers are one of the great sport fish, and their commercial fishery has been carefully managed, such that they are once again abundant (albeit not without problems).  Michael Pace (formerly CIES, nowadays at the U. of Virginia), student Kristi Arend (now Dr. Arend), and I studied the importance of food resources to the survival and recruitment of these species.  Here you see a larval striped bass, made transparent with a clearing agent, and you can see the water fleas (Bosmina) in its gut lumen.  We found that the timing of zooplankton increases, or "blooms," in the Hudson is very favorable for the young fish, and fish that are born before the blooms suffer from both low water temperatures and little food, while larvae hatched after the bloom are much more vulnerable to predators.

The Hudson River is one of the most beautiful, historic, and interesting estuaries!  Check out these websites:
Hudson River Foundation (research and education opportunities)

Hudson River Estuary Program (NY State Dept of Environmental Conservation website)
Clearwater, Riverkeeper, & Scenic Hudson (environmental organizations)

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