Archive for October, 2010

Turtle Guy to give talk at Mattapoisett Free Public Library

Monday, October 18th, 2010
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GateHouse News Service
Posted Oct 18, 2010

The Turtle Guy is coming to Mattapoisett Free Public Library at 3 p.m. Thursday, Oct. 28, to give an all-ages multimedia presentation on turtles at the 7 Barstow St. library.

The Turtle Guy Don Lewis and Sue Wieber-Nourse will give free presentation on turtles and how they live. Tiny turtles will be among the gems that they will share. For information, call 508-758-4171

Wicked Local Marion

Ctenophore Bloom in Sippican Harbor

Sunday, October 17th, 2010


Turtle Journal discovered a ctenophore (comb jelly) bloom in the shallows and covering the low tide sands of Silvershell Beach off Sippican Harbor in Buzzards Bay this morning.

Thousands of Depredated Surf Clams Wash Ashore on Scusset Beach

Friday, October 15th, 2010

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Depredated Surf Clam on Scusset Beach

Gusty winds from an early season nor’easter swooped down on Cape Cod Bay from the North Atlantic today.  Turtle Journal patrolled north facing beaches from Scusset in Bourne, on the west side of the canal, to Sandy Neck in Barnstable to see if any critters had been driven ashore and were in need of rescue. 

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Thousands of Surf Clams Litter the Wrack Line

We reached Scusset Beach around two in the afternoon at mid tide rising.  As we walked the shore we spotted thousands, probably tens of thousands, of small surf clam shells massed along the leading edge of the incoming surf for about a quarter mile of beach.  These small clams ranged in length from approximately 15 mm to 60 mm, with the greatest number of clams about 30 mm long.

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Depredated Surf Clams by the Thousands

Closer examination revealed that nearly every clam had been depredated with a neatly drilled hole penetrating to the soft animal inside the shell. 

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Drill Holes Clearly Visible in Depredated Surf Clams

We found no likely suspect predators mixed with the shells during our search of the Scusset shoreline.

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To provide a visceral sense of sizing, we placed a nickel on a pile of the surf clam shells and snapped the picture above.  On leaving the beach, we observed thousands of surf clam shells along the morning’s high tide line, partially covered in wind blown beach sand.

Cape Cod Killing Zone for Giant Ocean Sunfish

Wednesday, October 13th, 2010

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Giant Ocean Sunfish Strands in Wellfleet Harbor

Sadly, there has been a spate of ocean sunfish strandings and deaths in Wellfleet Harbor and elsewhere along Cape Cod Bay within the last week.  During this time of year pelagic ocean sunfish enter Cape Cod estuaries, apparently to forage in rich fall tidal waters filled with plankton and ctenophores.   Last week Turtle Journal observed a pair of ocean sunfish foraging in Wellfleet Harbor.  See Ocean Sunfish Pair Foraging in Wellfleet Harbor.  Wellfleet Harbor and other estuaries of the Outer Cape enjoy healthy flushing by as much as a 15-foot vertical tidal difference between the highest high tide (+13 feet) and the lowest low tide (-2 feet).  The flow of that much water through such narrow estuaries and along such extensive tidal flats creates a killing zone where these peculiar animals get trapped in the shallows, strand and die.

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Sue Wieber Nourse Examines Young Female Ocean Sunfish

On Saturday a young female ocean sunfish got trapped in Chipman’s Cove in Wellfleet Harbor and stranded.  She was likely the smaller of the two ocean sunfish that we saw foraging in the harbor last week.  Pam Harding, a fall vacationer in a cottage on exquisite Chipman’s Cove who had been alerting us to large megafauna in the harbor, reported the discovery of this sunfish and another one further along the beach.  We reached the fresh carcass early Sunday morning.

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Documentation of Young Female Ocean Sunfish

We collected morphometric data on this sunfish as she lay in the salt marsh just below the high water line.  She measured only 5 feet 2 inches from tip of snout to the trailing edge of her truncated caudal fin.  Her height from the bottom tip of the ventral fin to the top of the dorsal fin was 6 feet 4 inches.  The design of ocean sunfish and the way they swim through the water, as you can observe in our YouTube video in last week’s post, poses substantial risk in the inter-tidal shallows that swiftly empty during receding astronomical tides.

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“Truncated” Caudal Fin of Ocean Sunfish

The truncated caudal fin, also called a clavus (rudder), coupled with the very large span from ventral fin to dorsal fin, makes the ocean sunfish extremely vulnerable as it swims and forages in these inter-tidal waters. 

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Sunfish Pectoral Fin, Operculum over Gills, and Eye

A tiny pectoral fin lies immediately behind the gills which are covered by an operculum, all behind the eyes and the snout. 

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Ocean Sunfish Mouth and Fused Teeth

The open mouth shows the species’ fused teeth.  When we examined her gastro-intestinal track, we found plentiful amounts of digested food.  In every regard, she seemed an extremely healthy specimen with no indication of a cause of death other than being trapped in the killing zone.

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Young Female Ocean Sunfish Ovary

This ocean sunfish was identified as a young female because of the presence of a small ovary and her overall small size.

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Under the Microscope: Female Ocean Sunfish Oocytes

Examination of a slice of her ovary under a microscope showed healthy oocytes, consistent with her overall healthy appearance.

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Under the Microscope: Close-Up of  Ocean Sunfish Oocytes

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Don Lewis Reports Second Stranded Ocean Sunfish

A couple of hundred feet north along the wrack line, we found the second ocean sunfish, which had already suffered significant deterioration and decomposition.  This specimen had been dead for some time.

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Documentation of Young Male Ocean Sunfish

This small ocean sunfish measured a mere 4 feet 2 inches from snouth to caudal fin, and 5 feet 2 inches from ventral fin to dorsal fin.  The eye had already disappeared to predators that had also nibbled along the edges of the carcass.

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Exposed Bones of Ocean Sunfish Dorsal Fin

Several measurements, such as the width of the dorsal and ventral fins, had to be approximated because the skin had deteriorated. 

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Young Male Ocean Sunfish Testes

This small animal was identified as a young male by the testes.

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Small Ocean Sunfish Sliced by Propeller

On Saturday, Carol “Krill” Carson had responded to a report of an ocean sunfish at Linnell Landing in Brewster.  The carcass had come ashore about 2 PM in the afternoon.  This specimen was identified as a small male and measured between 4 and 5 feet long.  The location of deep prop slices at the top of this ocean sunfish suggests that a boat strike was the cause of death.

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Giant Ocean Sunfish Forages in Wellfleet’s Chipman’s Cove

Today, Wednesday the 13th of October, Krill discovered another extremely decomposed male sunfish north of Chipman’s Cove in Wellfleet Harbor across from Shirttail Point.  And, finally, around sunset tonight Pam Harding reported that she observed another ocean sunfish foraging in Chipman’s Cove, which she thought had departed the cove as the tide receded.  We will all keep a careful watch on the cove in the next few days and weeks as this killing zone continues to claim giant ocean sunfish.

Ocean Sunfish Pair Foraging in Wellfleet Harbor

Wednesday, October 6th, 2010

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Ocean Sunfish (Mola mola)

What a strange fish!  This giant ocean sunfish, seven feet from tip of dorsal fin (bottom right) to tip of ventral fin (top left), sports the signature abbreviated tailfin, called a caudal fin or clavus (rudder).  Her head is at the top right of the photograph with her tiny rounded pectoral fin immediately behind the eye.  While one can come across an ocean sunfish at sea basking on the surface in a flat position similar to the stranded Mola mola above, normally one finds an ocean sunfish swimming with dorsal fin cutting through the water, looking for all the world like a SHARK!

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SHARK!! (NOT … Ocean Sunfish)

Turtle Journal reached Wellfleet Harbor in mid afternoon as the late morning high tide receded.  Thick low clouds dumped torrents of rain on the pier, and schools of menhaden swam slowly along the floating docks largely camouflaged in the murky, plankton-thick water.  We visited the Wellfleet Pier today to check for signs of the large ocean sunfish we had discovered one week ago on September 29th.  (See Giant Ocean Sunfish in Wellfleet’s Chipman’s Cove. )  As Sue Wieber Nourse walked near the harbor master’s shack, she spotted a dorsal fin circling the harbor among schools of menhaden.

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Ocean Sunfish Pair in Wellfleet Harbor

This giant ocean sunfish was quickly joined by a smaller Mola mola as the pair foraged in tandem among the menhaden, while dodging diving gulls and busy shellfishermen boating out to their aquaculture grants.  The sunfish crisscrossed between piers and along the docks, then disappeared for several minutes, only to reappear and resume foraging behavior with dorsal fin occasionally slapping from side to side.

Ocean Sunfish Pair Forage among Menhaden Schools

The pair continued to forage and gradually swam into the deeper channel leading out to Wellfleet Bay as the receding tide lowered water levels near the pier.  Soon their dorsal fins blended into thick low misty clouds as they swam beyond the harbor jetty.  We will continue to observe these gentle giants during the coming weeks because many ocean sunfish strand during astronomic tides each fall along the Cape Cod bayside shoreline.  If you see an ocean sunfish in distress or merely circling close to shore within the next several weeks, don’t hesitate to call the Turtle Journal hotline at 508-274-5108.