Tag Archives: marine invertebrates

Low tide

Carol and I walked over to Fairhaven late this afternoon. By the time we got to the public access boat landing, the tide was quite low.

“Want to walk down on the beach?” I said to Carol. The beach in question is perhaps 100 feet long, a short section of muddy, pebbly beach in between the paved boat landing and the piers of the Coast Guard Auxiliary.

“OK,” she said. “First one to find the prize wins.”

We walked the short section of beach. There were lots or broken bottles, and small bits of plastic that had washed ashore. But there were also lots of shells, a surprising number of shells for such a disturbed section of shoreline. Particularly common were shells of the Common Slipper Shell, but there were also plenty of Ribbed Mussels and Northern Quahog.

“Look at this oyster,” said Carol, poking at a six-inch specimen of Eastern Oyster with her toe. It was a good shell, but it wasn’t a real prize.

I saw one or two other Eastern Oyster shells, a few Atlantic Bay Scallops, and some barnacles. I was looking for Common Periwinkles, which you can find in some of the most polluted parts of the harbor, when suddenly I spotted something very unusual half-buried in the muck. I pulled it out and held it up to show Carol: “Look, a sand dollar!” I said. The organism was dead, but the shell — technically called a “test” — was intact and perfect.

She came over to look at it. “You win the prize,” she said. It really was a prize — to think that a sand dollar was living in a marine industrial landscape! Carol had me rinse it off so we could take it home; and now it is sitting in our kitchen sink, drying out.

Gulls and crab

A few days ago, I was walking on Pope’s Island near the marina, seeing if any of the recreational boats had been taken out of the water yet. I happened to be watching as an adult Herring Gull suddenly swooped down and landed on the water right next to the rocks that make up the shore of the island. The gull stuck its head down in the water, balanced itself with a flurry of its wings, and came up with something in its bill.

The gull flew right in front of me, and landed in the marina’s parking lot about a hundred feet from where I was standing. It had a fair-sized crab, and it appeared that the crab was still moving. The gull lifted up its head, dropped the crab on the pavement, and quickly picked it up again. As far as I could tell, that drop was the coup de grace, and the crab no longer moved after that.

The gull shook its head with the crab in its bill, put the crab down, turned its head on the side, and pecked at the joint between the upper and lower shells. I walked a little closer as it repeated this maneuver several times. By now, it was pulling little bits of flesh out of the crab and gulping them down.

A second gull flew over, gliding in and landing a safe distance away, and watching the first gull eat. A third gull flew over to watch as well. But the first gull was very adept at eating the crab, and the other two gulls quickly gave up and flew away, either to search for food on their own or to find a clumsy gull from whom they could steal food.

Then a first-year gull flew over, awkward, with its drab brown plumage, and landed fairly close to the adult Herring Gull. It landed clumsily, hunched its shoulders, and gave the keening cry that baby Herring Gulls give when they’re in the nest asking for food from their parents. The adult gull shook the crab very hard a couple of times, and a couple of the crab’s legs flew off. The adult let the first-year gull steal one of the crab legs, which it quickly swallowed whole.

Pretty soon, it looked to me as though the adult had finished all the meat in the crab shell, so I ran over and chased the two gulls away to see what kind of crab it had been. All that was left was the top shell of a Green Crab (Carcinus maenas); its shell measured nearly six inches from point to point.

The light of the sun hanging low over the western side of New Bedford harbor practically blinded me; when I got closer to the water, it reflected up off the flat surface of the water, and I had to look down. Down at the asphalt pavement littered with broken shells left when the gulls dropped a quahog or a mussel to break it open and reveal the tender mollusc body inside. Broken shells and some bones, picked clean, probably bones of a small gull — that bone looked like a humerus, that one perhaps an ulna — and the tail end of a fish skeleton, left by returning sport fisherman, and picked clean by the gulls.

Out on the still surface of the water, sea ducks dove underwater to catch small fish. The fish in the harbor are filled with toxic waste, PCBs, which will accumulate in the fat of the ducks. The fish in the harbor are evolving to become tolerant of the toxic waste, although it took many generations of fish and lots of death to get there. The same will probably happen to the ducks.

A breeze riffled the surface of the harbor. I turned away from the sun. Three gulls flew away at my sudden movement. One immature gull, too stupid to know when to fly away, stayed, facing the sun behind my back. No haze to soften outlines or hide sharp edges: I could see each feather on its head.

The ducks aren’t bothered by the traffic on the highway. They see me and fly low across the water, their wingtips tapping its calm surface. On Pope’s Island, I can see every detail of a Lark Sparrow hiding in the bushes, even though I have forgotten my binoculars: the harlequin pattern of its head, the clear breast with a dark spot in the center.

Walking west, the sun blinds me and forces me to look away. Then it dips behind the city, the few last rays lighting up the top of the old New Bedford Hotel dimmed by clouds moving in from the west, and the sun sets for the last time on this year.

Molluscs and clean water

Long walk today up to Riverside Cemetery in Fairhaven; from there, I walked out on the point for views of the upper New Bedford harbor. Found some of the older gravestones in the cemetery, dating from the late 18th C.

On the walk back, I went down one of the side streets that terminates at the edge of the water. The tide was low, and I was able to walk out onto the shore, mostly sand but with an admixture of mud. A greater diversity of seashells than I had expected: people say that New Bedford harbor is essentially dead, that only killifish and quahogs live in its waters, but that was certainly not true this far up into the harbor. I first noticed some long meandering tracks through the sand of some small gastropod, which proved to be Common European Periwinkles (Littorina littorea). I picked one up by its shell: the mollusc clenched its body into the shell, but after I held it still for fifteen seconds, it relaxed, letting its foot come out, and then its two delicate black tentacles, which it wriggled gently; if the tentacles are where its chemoreceptor cells are located, and if its eyes are at the base of its tentacles, perhaps it was exhibiting a kind of molluskan curiosity. I placed it back on the sand, and it resumed its course down towards the verge of the water.

There was a small patch of salt marsh hay growing from the muck, which, when I got close to it, proved to support a large number of Atlantic Ribbed Mussels (Geukensia demissa), packed in so tightly that their shells touched and it was only in the interstices between the shells that the salt marsh hay could grow. All these living mussels pointed upwards; with the tide so low, they were all closed tightly. In addition to these living molluscs, I saw quite a few shells and shell fragments, of course including Northern Quahog (Mercenaria mercenaria) which is well-known to grow in the most polluted waters of the harbor, but also Atlantic Jackknife Clam (Ensis directus) which we always called “razor clams” when we were children, and Eastern Oyster (Crassostrea virginica).

It was getting late when I stopped at this little beach, and I suspect if I had had more time I could have found a few more species. Given this diversity of species, it may be that the water quality towards the upper end of the harbor (that is, nearer to the Interstate 195 bridge) may be fairly good; and this is the only place in the harbor thus far where I have seen living molluscs.

(Reference: Seashells of North America: A guide to field identification, R. Tucker Abbot (New York: St. Martin’s Press, 1968, 1986, 1996); in the “Golden Field Guide Series”.)

Winter beach

Drove to Horseneck Beach for a long walk today. I had a desire to walk down the beach and pick up a few shells and not think about anything but sun and sand and waves. A brisk westerly breeze kept me walking quickly until I drew near to the Westport River where the beach was somewhat protected by a low rise of land to the west. I slowed down and started looking at the beach.

A different mix of shells from the beach at Fort Phoenix: Most of the clamshells appeared to be Atlantic Surf Clams, and I don’t think I saw any quahogs. (I saw one clammer working the beach, and I would have liked to have asked her what she was raking in, but she was too busy.) I also found a good number of Blue Mussel (Mytilu edulis) shells, which we haven’t found at all at Fort Phoenix. I picked up two or three clamshells that I couldn’t identify; after looking at the “Marine Organisms Database” on the Web site of the Marine Biological Laboratory at Wood’s Hole, I believe the shells are either Transverse Ark (Anadara transversa) or Blood Ark Clam (Anadara ovalis), both of genus Anadara. It must be a somewhat different ecosystem along Horseneck Beach.

At one point, I saw a Great Black-backed Gull floating on the sea with something quite large in its mouth. I looked through the binoculars to see what the gull was carrying. It was a sort of pinkish color; the gull had to open its bill quite wide to hold onto whatever it was, and at one point it dropped the thing into the water, but quickly snatched it up again. I couldn’t for the life of me figure out what it was, and the gull’s eye glowed a brilliant, mysterious red in the setting sun. At last the gull flew ponderously up into the air, and I could see that it was carrying a Horseshoe Crab with the long tail dangling down. Off the gull flew, presumably to drop the crab onto something hard to break it open.

But mostly I just walked, and didn’t think of anything at all.


Walked to Fort Phoenix in Fairhaven yesterday.

Waves from Wednesday’s storm must have hit the beach at Fort Phoenix. Big rolls of seaweed, mixed with seashells and grains of sand, lay at the high tide mark. Most of the seaweed appeared to be Knotted Wrack (Ascophyllum nodosum), and true to its name its six-inch strands were knotted together, the bulbous ends impossibly tangled.

The seashells, as usual at Fort Phoenix, were thick between the low-tide and high-tide marks. The vast majority of the shells are always Common Slipper Snail (Crepidula fornicata), usually open and empty. But yesterday there were lots of live Common Slipper Snails clinging tightly to empty Northern Quahog shells (Mercenaria mercenaria).

Aside from the slipper shells and clamshells, the beach had the usual sprinkling of Common Jingle Shells (Anomia simplex) and Atlantic Bay Scallops (Argopecten irradians). I saw two Whelk shells, one which was a good seven inches long and was probably a Knobbed Whelk; the other I think is a Channeled Whelk. I found one Eastern Oyster shell (Crassostrea virginica), and one well-preserved shell of an Atlantic Horseshoe Crab (Limulus polyphemus). I did not find any of the delicate Ribbed Mussel shells (Geukensia demissa), although we found some there just last week.

I would estimate that there were twice as many gulls as usual at Fort Phoenix, many of them in the air: carrying shellfish in their bills, dropping shellfish until the shells cracked, harassing other gulls to steal a cracked shellfish away, or gliding along looking for more shellfish to pick up. The gulls use the summer parking lot, now empty of cars, as another rock on which to drop clams, cracking the hard shells open so they can eat the soft mollusc inside; although most of them still use the rocks at the edge of the sea.

I walked through the parking lot looking at the broken empty shells. Nearly all of them were clams, but I saw an occasional scallop, and one or two slipper shells. I watched as one Herring Gull dropped a clam; I heard it crack; the gull dipped into the broken shell with its bill, snatching out the soft inside, gobbling it down, all the while keeping a fierce lookout for nearby gulls who might steal its treasure.


In the late afternoon, I drove down to the hurricane barrier for a walk. A damp chilling breeze blew down the Achushnet River, and I walked along the outer side of the barrier to stay out of the wind. Out of the wind, the day was pleasant even if it was gray. The Martha’s Vineyard ferry went out through the barrier, scattering ducks and gulls as it picked up speed once in the outer harbor.

On the walk back, I walked down on the windward side of the hurricane barrier. The tide was quite low, low enough that you could walk out to little Palmer Island. As I got onto the island, over a hundred Brant took off together and flew low over the water up the harbor. Ducks were scattered everywhere over the water; a couple of Long-tailed Ducks bobbed in the water up near the Palmer Island lighthouse. The interior of the north end of the island was covered with trash; there was not a square foot that wasn’t covered with trash: a computer monitor without any glass, a square plastic bin, a chunk of foam padding, a worn two-by-four with rusty nails, styrofoam cups, plastic bottles, trash that can’t be identified. In the junipers near the lighthouse, half a dozen Yellow-rumped Warblers flew about cheerfully eating juniper berries. Invasive bittersweet and phragmites, dominated the vegetation of the upper end of the island, along with poison sumac; brambles and thorns grew here and there; a small remnant of salt hay grass clung to the east side of the island.

I scrambled off the island before the tide could cover over the mud and sand that connects it to the hurricane barrier; passed a dead horseshoe crab, stepped on a squishy bit of yellow foam, curnched over broken shells and bits of broken glass. I was cold, and hurrying back to the car, but something made me pause and look at one waterbird through the binoculars: a Barrow’s Goldeneye, close enough to see every detail; an uncommon duck that I just didn’t expect to see in the heart of the city.