Travel Reference
In-Depth Information
Takara-no Shima minshuku, located right on Izena Beach, is very popular with Japanese visitors.
Izena has a few satellite islets surrounding it, mostly to the south, but there's one on the
east coast near the harbor and a fairly large one to the north. The northern one, Gushi-kawa,
lies actually midway between Izena and Iheya. We'll describe it as we get to Iheya.
Box Jellyfish or Sea Wasp
Most of the roughly 2,000 species of jellyfish around the world are harmless, but not all. Jellyfish
capture their prey using nematocysts, a type of specialized singing structure. Although most sings
are mild enough to not be too bothersome for most people, some, such as the Portuguese Man o'
War (
Physalia physalis
), are paricularly painful, but rarely fatal. However, one group (class Cubo-
zoa) stands out as truly dangerous, even lethal. Commonly known as ”box“ jellyfish, they differ most
visibly from ordinary jellyfish in that their medusae (their ”umbrellas“) are cube-shaped, not round
or dome-shaped. Their umbrella's underside contains a mechanism whereby they can concentrate
and expel water in a jet-like fashion, thereby increasing their speed and allowing them to hunt their
prey. Most regular jellyfish merely drift in the ocean currents. Box jellies have a more highly deve-
loped nervous system than others and possess true eyes. Most ordinary jellyish can only disinguish
between light and dark. The most venomous species of box jellyfish are found in the tropical waters
of the Indo-Pacific, which includes Okinawa. There are at least three dozen different species spanning
half a dozen taxonomic families, but one of the most common and dangerous is
Chironex fleckeri,
,
commonly known as the ”sea wasp.“ It is an infamous lethal species living in warm coastal waters
from northern Australia to Vietnam. The amount of venom in one animal is enough to kill 60 adult hu-
mans. Its closely related cousin
Chironex yamaguchii
is the one most usually found in Okinawan wa-
ters where it is known as the Habu jellyfish (
ハブクラゲ
;
Habu kurage
). Their bodies are transparent
and thus almost impossible to see in the water. They are not large, only about 5-6 inches (12-15 cen-
imeters) in body dimension, with about 3-4 feet (1.5 meters) of trailing tentacles. The singing cells
of the
Habu kurage
contain poison clusters that burst, releasing strings of singers into an unwary
swimmer that can cause permanent scarring. The venom can cause the vicim to stop breathing and
even cause cardiac arrest. The box jelly's toxins attack the heart and nervous system. Some people
