Posts Tagged ‘tidal pool’

Five Star Day on West Island

Monday, October 13th, 2008

This afternoon we explored the shoreline of West Island in Fairhaven, Massachusetts.  West Island lies on the western shore of Buzzards Bay across the water from Woods Hole, Falmouth and Naushon Island on the east side.  The weather varied from overcast to broken sunshine with temperatures in the chilly 50s and a strong easterly breeze blowing in off the bay and ocean.

West Island on Left; Buzzards Bay in Center; Falmouth & Woods Hole on Right

West Island is not normally a specimen collector’s delight with shoreline filled inches deep and yards thick with codium and eel grass, but we chanced to arrive at dead low and we decided to explore the exposed tidal pools at the southern point of the island.

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West Island Shoreline with Heavy Codium & Eel Grass Wrack

It proved a five star afternoon: seastars, that is.  We had never found seastars on West Island before, but today they seemed scattered throughout the southern tip of the island, hiding in pools of water under rocks, foraging in tidal pools and hectored by ubiquitous seagulls.

First Seastar (Asterias forbesi) on South Point of West Island

Seastars (Asterias forbesi), often popularly called starfish, have five “arms” which can regenerate.  In fact, the natural history says that a seastar needs only a segment of the central disk along with one arm to regenerate into a new seastar.  We should be so lucky!  With mostly cloudy skies, brisk winds and chilly temperatures, seastars were moving even slower than their normal sluggish pace.  But while conditions weren’t in their favor, they did present us some great opportunities to document these magnificent critters.  The following sequence from our first seastar gives an overview of the creature’s dorsal (top) and ventral (bottom) sides.

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Seastar under Rock; Dorsal (top) and Ventral (bottom) Views

Seastars have spiny skin and belong to the phylum echinodermata along with sea urchins and sand dollars.   The top or dorsal surface of a common seastar consists of numerous scattered spines. Each of these spines are, in-turn, surrounded by tiny jaws called pedicellariae. The pedicellariae remove sand and other debris and occasionally snag passing prey.  The ventral (bottom) surface of the seastar’s arms is covered with tube feet that have suctions at the bottom of each foot.  Each tube foot works in coordination with other tube feet enabling the seastar to grasp prey or move about over various surfaces.  The orange spot in the dorsal core is called the madreporite and is responsible for the movement of water into the vascular system that controls the movement of the tube feet.  The clip below shows the tube feet in action as it moves a shell along one of its arms.

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Seastar Tube Feet on Ventral (bottom) Side of Arms

Seastars are said to prefer clams, quahogs, oysters, et cetera as prey, but will consume snails in a pinch.  Tube feet on the ventral (bottom) surface act like suction cups, securing each side of a bivalve shell while the arms pull them open.  The seastar then inserts one of its two stomachs into the prey and digestion occurs inside the clam, turning the mollusk into liquid that is guided into the seastar’s mouth by cilia on its arms.  The seastar sucks up the liquified clam.

Ventral Surface with Lots of Shelled Critters Moving Along Tube Feet

The second seastar we encountered had previously regenerated one of its arms which was obviously smaller than the other four.  This ventral image below illustrates the size difference.

Seastar with One Regenerated Arm

More active than the first seastar we had discoverd, this one showed off its speed as it “dashed” along a shallow tidal pool.  I know there are some who say that observing a sailboat race is akin to watching grass grow, but it’s clear that those folks have never invested time as spectators in the ultimate sport of champions: seastar racing.  If you have time to invest, we encourage you to enjoy the next two exquisite videos, beginning with the tube-foot dash through the tidal pool.

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Seastar Glides through Tidal Pool

For those who have survived the previous experience, you are well prepared for the ever-exciting seastar sport of gymnastics; that is, tumbling 180 degrees from ventral up to dorsal up.  Judging is based on artistic content, plus degree of difficulty.  A perfect five point landing earns the highest points, especially from the Eastern European judges who are more technically oriented.

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Seastar Acrobatics

We found another seastar hugging the underside of a rock and rescued a fourth from the ravages of pestering seagulls.  The fifth and last seastar we almost missed because it looked more like a butterfly lying in a shallow pool.  It had lost three of its arms and we thought we had run across a goner. 

“Butterfly” Seastar with Only Two Arms

But a closer examination revealed that this seastar had healed from its injuries and was a lively and healthy critter, perhaps proving the point that chopping up seastars only serves to create more seastars!

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Healthy Two-Armed Seastar

A surprising day for the Turtle Journal team.  Temperature, wind, clouds and season conspired against us.  But the gods smiled and gave us quite literally a five star day.

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Saving a Critically Endangered Sea Turtle

Friday, September 5th, 2008

Nature’s Classroom Teachers Find Endangered Sea Turtle

In keeping with the theme of this web site, “Saving the World One Turtle at a Time,” opportunity came knocking across the ether at 11:30 this morning.  Five teachers from Nature’s Classroom (http://www.naturesclassroom.org/Yarmouth.htm) had traveled to Chapin Beach in Dennis for field orientation on the last day before school resumes next week.  They spotted an apparently lethargic “sea turtle” in a shallow tidal pool.  While most folks would have walked on by figuring that the incoming tide would handle the situation, or while someone else might have made the absolutely wrong choice of tossing the turtle into the sea to fend for itself, the Nature’s Classroom teachers took action.  They called the sea turtle stranding center at Mass Audubon’s Wellfleet Bay Wildlife Sanctuary (508-349-2615) to report the sighting.  The sanctuary called us and the game was afoot. 

Speaking over cell phone with the teachers, we learned that they had a fairly good handle on what constituted a sea turtle, but they were unsure of its species.  We asked that they remain with the animal while we sped to their location … about a 45 minute drive.  As we reached Chapin Beach, the tide was flooding across the tidal flats with a vengeance.  Two teachers were “escorting” the sea turtle in the shallows between sandbars.  A brief look was enough to identify the animal as a Kemp’s ridley, one of the rarest and most critically endangered sea turtles in the world.  By size we could estimate its age at two to two and a half years old.  In other words, this animal was the typical juvenile sea turtle that we find cold-stunned on Cape Cod beaches from late October to December.  But the cold-stunning season is still six or seven weeks in the future.
 
 
Don Lewis Holds Rescued Juvenile Kemp’s Ridley Sea Turtle
 
En route to the beach, we had alerted the New England Aquarium that we were responding to this potential sea turtle stranding.  Now we called them back with the species identification and our assessment of the animal’s condition.  There were early indications, beyond its lethargic behavior when first observed by the teachers, of the potential for future cold-stunning.  The right rear quadrant of its carapace was covered with brown algae; algae was also beginning to form on the rear of the turtle’s plastron.  There was a coating of algae on the top of the animal’s head and some algae buildup on the trailing edge of both front flippers.  There were a few dings on the keel as though it had been wave-tossed against a rock groin or breakwater.  When we observe turtles of this size during the outset of the cold-stunning season, we see the same, but much more extensive, indicators.  At least by the time we arrived on the scene, this sea turtle had become quite strong and active.

Rescued Kemp’s Ridley Sea Turtle (Story in Video)

In conversations with the aquarium and by proxy with NOAA, we weighed three options: immediate release on site, medical examination at New England Aquarium, or immediate release on the southern side of Cape Cod into Nantucket Sound … so that it wouldn’t get trapped by cold waters within the bay and become hypothermic and cold-stun a month of so hence.  Based on our field assessment, the decision was made for us to release the animal into Nantucket Sound from a southern Cape Cod beach. 

We crated the sea turtle for transport in our Element.  (Thank the gods of science that field researchers always come equipped for field emergencies!)  We began the trek across the Cape with a short stop to visit with our friend & colleague Kara Dodge, currently a PhD candidate at UNH and formerly a NOAA sea turtle coordinator.  She had flipper and PIT tags to append and to insert, and it gave us a nice quiet space to acquire the morphometric information we always document for sea turtles found in Cape Cod Bay.
 
 
Don Lewis Reads Caliper and Kara Dodge Records Data
 
Next we rendezvoused at the beach with a photographer from the Cape Cod Times whom we had alerted while driving from Dennis.  With sea turtle stranding season only a few weeks in the future, we didn’t want to miss this opportunity to use a photo-op to make people aware of what’s coming and what they should do and who they should contact.  By 3:15 in the afternoon we had released this fully charged sea turtle into the sound.  When we let it go into the oncoming surf, the turtle exploded forward like a hotrod leaving salt spray rather than rubber as it accelerated from zero to sixty faster than you could say, “Kemp’s ridley.”
 
 
Release of Rescued Kemp’s Ridley into Nantucket Sound
 
Finding a Kemp’s ridley sea turtle in Cape Cod Bay other than on the beach during the cold-stunning season is an extremely rare event.  There has only been one other such happening several years ago of which I am personally aware.  In that case the decision was made to tag it and release it back into Cape Cod Bay with an extremely unsatisfactory outcome a month or so later.  This time we maximized the odds that one of the most critically endangered species would have one more juvenile turtle to grow into adulthood and help restore its population.  We hope to see this turtle’s flipper tags or detect its PIT tag on a nesting beach in Rancho Nuevo, Mexico in another 15 or 20 years.  Or at least we hope that our successors in turtle conservation will see the fruit of today’s adventure in a couple of decades.  (ASIDE:  We’ve always considered it a bit unfair that sea turtles outlive sea turtle researchers.)
 
A hearty bravo to Nature’s Classroom without whose intelligent action this morning, nothing good would have come of today’s event.  And thanks also to a team of dedicated volunteers and professionals from Mass Audubon, the New England Aquarium, UNH and NOAA who responded to the challenge, made the best decision for the animal’s survival and flawless executed its impromptu rescue and release.  And that’s how we intend to save the world:  one turtle at a time.
 
 
Don Lewis Releases Endangered Kemp’s Ridley Sea Turtle

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