Unusual Visitors Arrive On Our Shores

0
2

Among the interesting sightings last week were the Portuguese man-of-wars and loggerhead sea turtles. Both species were found washed ashore, and dead, on East End ocean beaches. Between the two, the man-of-wars caused the biggest stir among beachgoers.The Portuguese man-of-war (Physalia physalia) shares many characteristics with some of our commonly encountered jellyfish and is often mistakenly referred to as one. But other than its being armed with stinging nematocysts to capture small prey—and to instill fear among human beachgoers—it is quite different from jellyfish (members of the class of organisms called Scyphozoa) and listed in a separate class called Siphonophores.

My somewhat dated reference books that discuss this species claim that there are no records of its sting resulting in a fatality among humans, despite tens of thousands of people being stung by this cosmopolitan, warm water species in Australia alone each year. However, an internet search revealed that there have been a few deaths noted in recent years; it appears that, in these cases, the sting led to a type of severe allergic reaction called anaphylactic shock that, in turn, ended in fatalities.

One of the most distinctive features of the Portuguese man-of-war is its striking inflated bladder. A significant portion of the balloon-like bladder contains carbon monoxide that is generated by the organism. The bladder acts like a sail, enabling this creature to move through the water independent of marine currents and, depending on the wind, faster than its jellyfish neighbors.

One of my references, an excellent book titled “The Wild Edge: Life and Lore of the Great Atlantic Beaches” by Philip Kopper, states that “… the animal manipulates its sail to a degree in order to catch the wind and move in a chosen direction—like a skillful windsurfer.” Despite this skill, it is not uncommon for a steady southerly blow to shipwreck a number of them on Long Island’s ocean beaches, as happened last week.

When threatened at the surface, it can deflate the bladder and sink below the water surface, a strategy whose utility seems questionable when one considers the swimming abilities of its known predators, the loggerhead and a number of fish species, including the largest bony fish in the world, the ocean sunfish (Mola mola).

A much less obvious feature of the Portuguese man-of-war, but one that is even more unusual than its inflated sail bladder, is the fact that each is not a single individual but instead is made up of a colony of many minute, mutually dependent, specialized organisms, called zooids.

One of my colleagues at The Press, Colleen Reynolds, covered many other aspects of this creature in an article published last week, titled “Venomous Man-Of-Wars Wash Up At Beaches.” If you missed it, look for it on 27east.com.

Three loggerhead sea turtles (Caretta caretta) washed ashore in East Hampton last week—all were dead—and a fourth was successfully freed, alive, from fishing gear by the Coast Guard. This is the most abundant sea turtle found in coastal U.S. waters.

As a group, sea turtles are most easily recognized by their large, paddle-like legs that do not end in anything resembling a “foot.” Rather, the leg appendages resemble fins or flippers, an adaptation for their extremely aquatic lifestyle that includes the open ocean.

Loggerheads are named for their disproportionately large head relative to the rest of their body. The oversized head supports large, powerful jaws capable of crushing whelks, conch, oysters and other hard-shelled prey in addition to soft sponges, jellyfish and Portuguese man-of-wars.

Hatchlings average 2 inches in length and tip the scales at a mere 0.05 pounds. They immediately head for the sea and, in what is best described as a “swim frenzy period” that lasts for several days, the tiny hatchlings make their way to Sargasso mats far offshore, where they reside for the first phase of their aquatic life.

The lifespan for this species remains unknown. But it takes 35 years for them to reach sexual maturity and breed. Average sizes and weights for adults found on the U.S. Atlantic Coast are 3 feet and 250 pounds—therefore, over the course of its relatively long life, the loggerhead increases its weight more than 5,000 times!

Loggerheads are circumglobal, occurring throughout the temperate and tropical regions of the Atlantic, Pacific, and Indian oceans. Here, in the western Atlantic, they range as far north as the Grand Banks off Newfoundland, and as far south as Argentina. Females in the Pacific race of loggerhead make an incredible journey between their feeding grounds off the coast of Mexico to their nesting beaches in Japan … a 7,500-mile swim!

The only time loggerheads come ashore is to nest. Females will lay three to five nests per season (April to September, peaking in June), depositing approximately 125 eggs in each nest, for a sum total of 35 pounds of eggs per season!

The closest nesting area to Long Island is in Virginia, but 80 percent of the nesting for the eastern U.S. area occurs in Florida, and 25 percent of all loggerhead nesting in the United States takes place in the Archie Carr National Wildlife Refuge on Florida’s east coast, where researchers have recorded nesting densities of 1,000 nests per mile of beach. Named after the famous herpetologist, this refuge is the most important loggerhead nesting area in the Western Hemisphere.

The northwestern Atlantic population is listed as “threatened” under the Endangered Species Act. Threats to this species are many and varied: loss of nesting habitat due to coastal development and beach armoring, watercraft strikes, commercial fishing by-catch, entanglement in marine debris, and disorientation of hatchlings due to beachfront lighting.

Stranded and dead sea turtles should be reported to the Riverhead Foundation, (631) 369-9829.

Facebook Comments