Hudson River Almanac May 29 - June 3, 2007
Highlights of the week are not always celebratory moments. The first occurrence of the Chinese mitten crab, an invasive alien crustacean, had been anticipated, as was the zebra mussel's arrival in the early 1990s.
HIGHLIGHT OF THE WEEK
6/3 - Nyack, HRM 27: When Mike Frank hauled Captain Bob Gabrielson's crab pot over the gunnel of their boat near the Tappan Zee Bridge, he knew they had caught something different. Among the dozen blue crabs was an alien, an adult male Chinese mitten crab. The mitten crab, so-called for what appear to be furry mittens on its claws, was the same size as the number one jimmy crabs in the trap.
- Tom Lake
[The Chinese mitten crab is native to estuaries of China where it is highly regarded in the market. Mitten crabs are catadromous, meaning that they spend much of their life in freshwater, then return to higher salinities in the lower estuary (15-20 parts per thousand salt) to reproduce. The salinity gradients of east coast estuaries like the Chesapeake Bay, Delaware Bay, and Hudson River are nearly ideal for them. Adult mitten crabs have a carapace width of about 3", but their legs are almost twice that length, giving them a spider crab look. Unlike the native blue crab, mitten crabs are burrowing crabs, similar to our mud crabs only many times larger. They have a generalist diet, and their potential ecological impact on east coast estuaries is still unknown.
The Chinese mitten crab was inadvertently introduced to Europe in the 1930s and is now widespread. The first U.S. specimen was caught in San Francisco Bay in 1993, though it may have been there earlier. The species appeared on the Atlantic coast in Chesapeake Bay in 2005. One more followed in 2006, and another this year. Already, 4 mitten crabs have been collected from Delaware Bay this year. All 7 of these crabs, like the one from the Hudson, have been males.
The Marine Invasions Lab at the Smithsonian Environmental Research Center in Edgewater, Maryland, is working with U.S. Fish and Wildlife Service, the National Oceanic and Atmospheric Administration, and the Maryland Department of Natural Resources in monitoring their presence. It is illegal to import mitten crabs into the United States, but there is genetic evidence that the east coast mitten crabs arrived here from Europe via commercial traffic, much like zebra mussel did.
If you encounter a mitten crab in New York State, please notify Leslie Surprenant, NYSDEC Invasive Species Management Coordinator at (518) 402-8980 or firstname.lastname@example.org. Also notify Carin D. Ferrante, Smithsonian Mitten Crab Coordinator email@example.com. Do not release them alive! If you have a camera, take both dorsal (top) and ventral (bottom) views so we can determine its sex. Tom Lake.]
NATURAL HISTORY NOTES
5/29 - Stockport Flats to Catskill, HRM 122-113: The NYSDEC Hudson River Fisheries haul-seining crew netted relatively few fish today, and no American shad. Kris McShane, who coordinates the haul-seining, told me that the crew had netted only 196 American shad this year, significantly less than past years. While those results are disappointing, they could be due to the vagaries of sampling. Commercial shad fishers in the area did reasonably well this spring. Over the river, three migrating ospreys and a flight of brant passed by. The brant, as we saw last year, refused to go under the power lines that crossed the river near Athens. They turned and headed west to cross over them at a different spot. Near Stockport Flats we saw 3 bald eagles on the wing, one adult, 2 immature.
- Steve Stanne
5/29 - Hunter's Brook, HRM 67.5: As the glass eel sampling season nears its end, we walk the low-water streams in sandals through a haze of black flies with a bouquet of honeysuckle and Dame's rocket in the air. No eels today but there was our second dusky salamander of the spring. A female white sucker was very slowly making her way upstream, from tidepool to puddle to short runs, wiggling over the wet gravel and pebbles and around the cobbles. She was exerting much energy, leading me to think that this spawning run was going to be a one-way trip for this fish.
- Tom Lake
5/29 - Croton River, HRM 34: There were 6 osprey circling over the mouth of the Croton River just inside the railroad trestle today, the most I had ever seen at one time.
- Scott Craven
5/29 - New York City: The state's greatest concentrations of nesting egrets, night herons, and other long-legged wading birds are in, of all places, New York City. Today New York City Audubon announced that its HeronCam is now providing live video of one of the rookeries, located in the Bronx, thanks in part to DEC funding from the Environmental Protection Fund through the Hudson River Estuary Program. To view the birds, go to New York City Audubon's website at www.nycaudubon.org .
5/30 - Purling, Greene County, HRM 125: Waking up early as usual, I went out to get some cool fresh air at 4:30 AM. In the distance I could hear a whip-poor-will calling. These birds seem to be getting scarcer all the time.
- Larry Biegel
[DEC has listed the whip-poor-will as a species of special concern in New York State. According to the Birds of North America on the Cornell Laboratory of Ornithology's website http://bna.birds.cornell.edu/BNA/, most ornithologists agree that this bird now occupies less of its available breeding range than it once did. Habitat loss to agriculture, closing of forest openings due to growth and succession of trees, and urbanization, along with resulting increases in predation and loss of feeding habitat, are thought to be among the factors involved. The site notes that our knowledge of this nocturnal, cryptic species is poor. Steve Stanne.]
5/31 - Hunter's Brook, HRM 67.5: On the last day of spring sampling the net held a single glass eel. This eel, about 9 months old, probably entered the estuary 6 weeks ago as a translucent, bordering on transparent, juvenile. Since then it had adapted to the brackish to fresh inshore waters of the Hudson by gaining pigmentation until today it was a 2" black thread, more like obsidian than window glass. The number of glass eels recruited by this small tributary this spring was the lowest in five years of sampling. Alternating seasons of relative abundance and scarcity make it very difficult to see a population trend. Like all natural systems, however, cycles of abundance and scarcity have to be looked at over a much broader period than five years.
- Tom Lake
6/1 - Poesten Kill, HRM 151.5: We visited the tidal Poesten Kill at Troy with a backpack electro-shocker. Among the fish we caught, 2 were unusual for that tributary: an adult sea lamprey and 2 moderately large yellow bullheads. We had not seen yellow bullhead in the Poesten Kill before and this catch adds to our observations that it appears to be expanding its range in the Hudson Valley. We had never seen an adult sea lamprey in the Poesten Kill either.
- Bob Schmidt, Bryan Weatherwax
6/1 - Esopus Meadows, HRM 87: Today was a good lesson in the diversity of reproduction and the steady pulse of evolution. On my commute into work, I came across a 12" white sucker expiring at the mouth of the Klyne Esopus Kill at Esopus Meadows. It had likely exhausted itself during a spawning run up the small creek. I nudged it to deeper water, but I think it had run its course. Later in the evening, on a jog through the same area, I came across a gorgeous wood turtle (8" carapace length) trying to scrape a nest in the hard gravel of the Esopus Meadows Point Preserve's access road. Coincidently, like a crimson sentinel, a bright red eft (a terrestrial stage of the eastern newt) had paused on its amphibious walkabout not a foot away. I sat down a few paces away to think about the amazing and different life story of each of these three creatures; the challenges each of these remarkable individuals had already faced; the incredible evolutionary steps they represented, from aquatic fish to terrestrial reptile; all of them trying to keep their species vibrant, surviving, running their race. After a few minutes, I kept running too.
- Chris Bowser
6/1 - Town of Poughkeepsie, HRM 67: They is nothing quite like the sound of crows "mobbing" to catch your ear. In midday I could hear the nearly deafening racket of 50 or more crows in the woods in back of my house. This usually means a raptor is being harassed but the numbers of crows involved far exceeded anything normal. The leaves on the trees obscured my view except for the unrelenting black crow shapes that sprang from limb to limb. After a minute, a huge dark bird passed between the largest of the black locusts. It was an adult bald eagle; the blue leg band led me to believe it was the female of the local breeding pair from nest NY62. She made her escape.
- Tom Lake
6/1 - Fishkill, HRM 61: Sometimes critters wander through our yards, sight unseen, and it is probably better that way. However, many leave us with tokens of their presence. Recently, in a corner of our yard, I found the shed skin of a 3.5' black snake. A day or two later, I found the smaller shed skin of a garter snake on a nearby wall. Being the loving father that I am, I re-gifted these natural gifts to my daughter for use in her 4th grade class at Holy Trinity School in Poughkeepsie.
- Ed Spaeth
6/2 - Delmar, HRM 143: I was leading a wetlands walk at Five Rivers Environmental Education Center on a hot muggy day. We had seen only a few dragonflies, damselflies and red-wing blackbirds until we walked out on the bridge over the Beaver Tree Pond. We spotted 3 large snapping turtles swimming lazily around, waiting to see if we were going to give them a snack. A painted turtle, dwarfed by the big guys, was getting his own meal of algae off the back of the snappers. They didn't seem to mind until he tried pulling algae off a tail. When a snapper came up on the surface, the little guy just hitched a ride back out into the pond.
- Dee Strnisa
6/2 - Fishkill, HRM 61: As dawn was breaking over my yard, I watched a lone little brown bat making its last few forays for insects of the night.
- Ed Spaeth
6/2 - Denning's Point, HRM 60: The bay was 90 minutes from high tide as we watched spawning carp breaking the water all over the place. The water chestnut continues to thicken with the arrival of warm weather.
- Mike Boyajian, Jeri Wagner
6/2 - Tappan Zee, HRM 27: Our blue crab season, not even a month old, has been very good so far. The fact that we have a nice run of bunker [menhaden] in the river certainly helps. Our jimmy crabs have been as big as I've ever seen. In our bait nets we are also catching bluefish to 8 pounds.
- Bob Gabrielson Sr.
[Atlantic blue crabs have several colloquial names known mainly to rivermen and crabbers: Adult males are called "jimmies," mature females are called "sooks," and immature females are known as "sallys." Tom Lake.]
6/3 - Newcomb, HRM 302: By 7:00 AM this morning, it was already hazy, hot, and humid. Deer flies were out and the mosquitos were doing their thing. I found one nest with three blue eggs along our nest box trail on the golf course. I haven't checked mine at home, not wanting to disturb the new "parents." I figure that seeing them flying in and out of the boxes is a good enough clue that they are there. Cinquefoil and blue-eyed grass are blooming, and ox-eye daisies are budded out already.
- Ellen Rathbone
6/3 - Fishkill, HRM 61: We saw our first hummingbird of the season, today, a female. It was feeding on our sage blossoms, moving around them sideways, up and down.
- Mike Boyajian, Jeri Wagner
6/3 - Crugers, HRM 34: Coffee in the morning on the front porch can bring out so many sights: boats on the river, deer running through the yard, so many birds. One stood out today, a male pileated woodpecker. A handsome devil, I must say. My camera always being near I got the shot. A real collector.
- John Hamburger