colonial siphonophore that inhabits the surface of the ocean. It is constructed of a blue or pink-violet and
iridescent floating sail (pneumatophore), nitrogen and carbon monoxide filled and up to 30 cm in length, from
which are suspended multiple nematocyst-bearing tentacles, which may measure up to 30 m in length. It has
recently been reported that an Australian version of Physalia physalis is present in north Australian waters.
This jellyfish is characterized by float lengths of up to 15 cm, up to five thick dark blue "main" tentacles, and
up to ten other long, thin, and pale-colored tentacles. The smaller Pacific bluebottle (Physalia utriculus)
usually has a single fishing tentacle, which attains lengths of up to 15 m. In some species the sail can be
deflated to allow the animal to submerge in rough weather.
The physaliae depend on the winds, currents, and tides for movement, traveling as individuals or in
floating colonies that resemble flotillas. They are widely distributed but seem to abound in tropical waters and
in the semitropical Atlantic Ocean, particularly off the coast of Florida and in the Gulf of Mexico.
Envenoming has been reported as far south as the coast of Brazil. Their arrival at surf's edge can transform a
halcyon vacation into a stinging nightmare. Unfortunately, peak appearance time for both the man-of-war and
sea nettle is July through September, which is prime beach season.
As with icebergs, the scene above water conceals much of the story. Because the tentacles are nearly
transparent, they pose a hazard to the unwary. As the animal moves in the ocean, the tentacles rhythmically
contract, sampling the water for potential prey. If the tentacle strikes a foreign object, the nematocysts are
stimulated and discharge their contents into the victim. Each tentacle in a larger specimen may carry more
than 750,000 nematocysts. To increase the intensity of the "attack, the remainder of the tentacle shortens in
such a way as to create loops and folds, presenting a greater surface area and number of nematocysts for
offensive action in what are called "stinging batteries."
Detached moistened tentacles, often found by the thousands fragmented on the beach, carry live
nematocysts capable of discharging for months. Air-dried nematocysts may retain considerable potency, even
after weeks. The loggerhead turtle (Caretta caretta) feeds on Physalia. Like the clownfish with the sea
anemone, the brightly colored fish Nomeus gronovii has a unique symbiotic relationship with the man-of-war,
living freely among the tentacles. Two species of nudibranch (sea slug), Glaucus atlanticus and G. glaucilla,
eat the tentacles and nematocysts of P. physalis. The nematocysts are not digested and ultimately reside in the
dorsal papillae of the nudibranchs, where they may sting on contact. Other nudibranchs are also able to ingest
hydroids and store their stinging cells in the cerata, or flesh appendages. Dermatitis can also result from
contact with water containing venom that has already been released from stimulated nematocysts. The
Mediterranean octopus Tremoctopus violaceous stores intact dactylozooid segments in its suckers for later
use.
Gonionemus species. These small hydrozoans are distributed worldwide, but have only been reported as
causing severe envenomation in the Sea of Japan near Vladivostock, and the northwest shores of Honshu
Island. It is a small creature of 5 to 15 mm in diameter across the bell, with a symmetrical, right-angled cross
visible in the transparent part.
When the reaction is painful, the victim suffers muscle, joint, chest, and pelvic pain for up to 3 days. There
may be muscle fasciculations. In a respiratory presentation, the victims suffer rhinitis, tearing, hoarseness,
cough, and shortness of breath. In addition, there may be a combination of symptoms, with or without sore
throat, tachycardia, vomiting, and mild hypertension. Psychiatric depression and hallucinations may occur.
It has been noted that envenomation may occur beneath a bathing suit. In addition, a similar syndrome was
reported following ingestion of raw seaweed, to which was presumedly attached the jellyfishes.
Seabather's Eruption
Seabather's eruption, commonly termed "sea lice" ("pika-pika" around the Belize barrier reef; "sea
poisoning," sea critters," and "ocean itch" are other names), refers to a dermatitis that results from contact
with ocean water.
57
It has become a seasonal problem afflicting ocean-goers in south Florida and across the
Caribbean. It predominantly involves covered areas of the body and is commonly caused by pinhead-sized
(0.5 mm) greenish-brown to black larvae of the thimble jellyfish Linuche unguiculata, which breeds in
Caribbean waters throughout the summer with a peak in May.
118
L. unguiculata exists in three other forms
during its life cycle: schyphistomae (polyp), ephyra (first swimming stage), and adult medusa.. It is likely that
the adult and ephyra L. unguiculata can also initiate the eruption. Another culprit off Long Island, New York,
has been the planula larval form (visible at 2 to 3 mm) of the sea anemone Edwardsiella lineata, which carries
