Box jellyfish beach invasion has subsided

The recent box jellyfish invasion appears to have subsided. Nearly three dozen swimmers were treated on the beaches of New Smyrna Beach and Daytona Beach by lifeguards earlier this month while two others sought treatment in the emergency room of New Smyrna Beach's Bert Fish Medical Center.

Immersing the part stung into hot water with epson salts for a minimum of 20 minutes usually alleviates a lot of the pain. The sting of the box jellyfish is worse than that of the common jelly fish, but not nearly a s bad as its pacific cousin.

The Indo-Pacific or Australian box jellyfish is claimed to be the most venomous marine animal known to mankind and its sting is often fatal. Thankfully, these creatures are far from our shores. This extremely poisonous marine stinger frequents Australia's northern oceans all year round.

Fishing report

  • The sea water temperature at Ponce Inlet is 26.4 °C (80 °F).
  • Bluefish over two feet long, Spanish mackerel, and pompano are feeding upon the baitfish in the surf and around the inlet. Whiting are very close to shore.
  • The best time to fish this area reportedly in the last hour of the rising tide and the first few hours of the falling tide. Fishing for trout with top water baits is best in the morning.
  • Reds are apparently not schooling and are in singles or doubles.
  • In the creeks, there have been good catches of red drum, black drum, mangrove snapper, snook and flounder. In the Tomoka River and basin, there are reports that some sizeable tarpon are still feeding.

Test throughout Florida beaches on both coasts show red tide organisms not appreciable

Karenia brevis, the Florida red tide organism, was not detected in water samples collected this week in the Indian River Lagoon (Volusia and Brevard County) or alongshore of St. Lucie County.

The Florida red tide organism, was not detected in water samples collected this week alongshore of Okaloosa County or offshore of Escambia, Okaloosa, Walton and Hernando counties.

Other counties where the red tide did not measure up were in water samples collected this week alongshore of Pinellas, Hillsborough, Charlotte, Lee and Collier counties or offshore of Sarasota and Collier counties and the Florida Keys (Monroe County).

Two samples (out of 28 total samples) collected alongshore of Sarasota County contained background concentrations of K. brevis and one sample collected alongshore of Manatee County contained very low concentrations of K. brevis.

Meet the coconut crab: also known as the robber crab, with good reason

Courtesy photo

Here is an example of a coconut crab.

The coconut crab, also known as the robber crab, is an arthropod (defined as an invertebrate animal having an exoskeleton or external skeleton, a segmented body, and jointed appendages).

It is the largest land dwelling arthropod in the world and is probably the ultimate limit of how big animals with exoskeletons can grow in today’s environment. Inhabiting the coastal forest regions of many Indo-Pacific islands, the crab is sympatric with man albeit there are a few areas where the crabs have become extinct like in Mauritius and Rodrigues.

Since they are primarily nocturnal, they are virtually never seen and only emerge only at night to forage. Their body of the coconut crab is divided into four regions: the cephalic lobe, forepart, trunk, and opisthosoma (stomach).

It is a highly apomorphic hermit crab and is known to crack coconuts with its strong pincer claws in order to eat the contents. Like most decapods, the body of the coconut crab is divided into a front section, cephalothorax, ten legs, and an abdomen. The front most pair of legs has large claws used to open coconuts, and these claws can lift up to 64 pounds.

As with other hermit crabs the next two pair of legs are powerful walking legs, which are strong enough to allow the coconut crab to climb vertically up trees (often coconut palms).

The fourth set of legs is smaller with tweezer-like chelae (claws) at their tips, allowing the young crabs to grasp the inside of a shell or coconut husk to carry for protection. Adults use this pair for walking and climbing.

The fifth and last pair of legs is quite small and serves only to clean the breathing organs. The last set of legs is usually held inside the carapace in the cavity containing the breathing organs. The color of the crabs is different depending on what island they are on. They range from light violet thorough deep purple to brown.

Most of the literature is of a popular nature and can be traced back to the accounts of early travelers in the Tropical Pacific and Indian Oceans. These writings usually discussed the coconut crabs habits of climbing coconut palms, clipping off nuts, returning to the ground to husk and hammer open the coconut or carrying the husked nut back up the palm tree and dropping it repetitively on the rocks below until the coconut breaks. Many of the early observers admitted that their perceptions were second-hand. Based upon such accounts, in 1767 Linnaeus named the crab latro, or robber (of nuts).

These habits continued to be described in the zoological texts, despite the void of first-hand accounts in the scientific literature of how the crab husked and opened coconuts. The coconut crab is also known as the robber crab or palm thief because some coconut crabs are suspected of stealing shiny items such as pots and silverware out of houses or tents. However, this is largely passed on as a rumor.

They are also known as terrestrial hermit crab, due to the use of shells by the young animals; however, there are other terrestrial hermit crabs, which do not get rid of their shell even as adults. Although coconut crabs are a derived type of hermit crab, only the juveniles use salvaged snail shells to protect their soft abdomens. Sometimes, adolescent crabs will use broken coconut shells to protect their abdomens.

The adult coconut crabs do not carry shells, but instead harden their abdomen terga (dorsal segment other than the head) by depositing chitin and chalk. This act protects the coconut crab being constrained by the physical confines of living in a shell and allows this species to grow much larger than other crabs in their family. Like most true crabs the coconut crab bends it tail underneath its body for protection. The hardened abdomen protects the coconut crab and reduces water loss on land, but has to be molted at periodic intervals.

Between May and September, especially between early June and late August, male crabs develop spermatophores and deposit a mass of spermatophores on the abdomen of the female.

The abdomen opens at the base of the third pereiopods, and fertilization is thought to occur on the external surface of the abdomen of the female as the eggs pass through the spermatophore mass. The extrusion of eggs occurs on land in crevices or burrows near shore. Shortly thereafter; the female lays eggs and glues them to the underside of her abdomen. She carries the fertilized eggs underneath her body for a few months.

The eggs hatch in October or November as the female coconut crab releases the eggs into the ocean at high tide. The larvae are of the zoea type, which is the usual type for decapod crustaceans. The crab larvae float in the pelagic zone (any water in the sea that is not close to the bottom or near to the shore) of the ocean along with other plankton for about thirty days during which a large number of them are devoured by predators.

After three zoeal stages, the larvae reach the glaucothoe stage of development where they settle to the bottom, seek out and wear a suitably sized vacated gastropod shell, and migrate to the shoreline with other terrestrial hermit crabs. At that time they sometimes visit dry land.

As with all hermit crabs, they change their shells as they grow. After four weeks, they permanently leave the ocean and lose their ability to breathe in water. Young coconut crabs that are unable to find a suitably sized seashell will seek out a broken piece of a coconut hull. When they outgrow their shells they develop a hardened abdomen.

After four to eight years of life, the coconut crab matures and can reproduce. This is an unusually long period of development for a crustacean. Another distinctive organ of the coconut crab is its ability to smell. Certainly it does not have a nose like many mammals.

The process of smelling for the coconut crab works very differently and is dependent upon whether the smelled molecules are hydrophobic molecules in air or hydrophilic molecules in water. Since most crabs live in water, they possess specialized organs called aesthetascs on their antennae to determine the direction as well as the concentration of the smell.

However, coconut crabs live exclusively on land and the aesthetascs on their antennae differ considerably from those of other crabs and look more like sensilia, the smelling organs of insects. The coconut crab also has the ability to flick their antennae like insects to enhance their reception. This allows them to have an excellent sense of smell which detects interesting odors over large distances.

The smells of bananas, coconuts, smells of rotting meat especially catch the crabs attention as potential food sources. Except as larvae, coconut crabs cannot swim and even small specimens will drown in water. In order to breathe, they use a special organ termed a branchiostegal lung, which can be interpreted as a developmenrtal stage between gills and lungs.

The branchiostegal lung contains tissue similar to that found in gills but is suited for .absorption of oxygen from the air rather than water. This organ is expanded laterally and is evaginated to increase the surface area of the organ. Located in the cephalothorax, the branchiostegal lung is optimally placed to reduce both the blood gas diffusion distance as well as the return distance of oxygenated fluid to the pericardium of the heart. As mentioned earlier, the coconut crabs use their fifth set of legs to clean the breathing organs and to moisten them with water.

The organs need water to properly function, which is provided by the crab by its stroking its wet legs over the spongy tissues nearby. The coconut crabs may also drink water from small puddles by transferring it from their cheipeds to their maxillipeds. In addition to the branchiostegal lung, the coconut crab has an additional rudimentary set of gills, which are comparable in number to the aquatic species of hermit crab families of the order decapoda.

They are reduced in size and have comparatively less surface area. While the gills were probably used to breathe under water in the evolutionary history of the species, they no longer are able to provide sufficient oxygen which led to a decreased dependence on the gills for gas exchange and the development of other means for respiration.

The diet of the coconut crab consists primarily of fleshy fruits, nuts, and seeds. Hiowever, they are also omnivorous crustaceans and will also consume other organic materials such as tortoise hatchlings, other dead animals, other sympatric crabs, and scavenge on the dead of their own kind. During a tagging experiment, a coconut crab was observed catching and eating a Polynesian Rat.

In an article published in Discovery News on October 23, 2009, written by Rosella Lorenzi, recent discoveries have suggested that the coconut crab may be responsible for the disappearance of the remains of Amelia Earhart by consuming the remains after her death and hoarding her bones in its crab burrow.

For more details on this subject I refer you online to: http://news.discovery.com/history/amelia-earhart-resting-place.html.

Coconut crabs often try to steal food from each other and will pull their food into their respective burrows to be safe while eating. Coconut crabs climb trees, not only to eat coconuts or fruit, but to escape the heat and to escape predators. Sometimes the coconut crab will not take the husked coconut up the tree but will cut a hole in it with their strong claws and eat the contents a behavior unique in the animal kingdom.

Depending on the terrain, the coconut crab lives alone in underground burrows and rock crevices. They dig their own burrows in sand or loose soil. As mentioned before they stay hidden most of the day for protection and to reduce water loss from the heat.

The burrow of the coconut crab contains very fine, strong fibers of the coconut husk which the animal uses as bedding. When it is resting in its burrow it uses one of its claws to close the entrance of the burrow creating a moist environment within the burrow, which is necessary for its breathing organs. However, in areas that have a large coconut crab population, some may venture out to gain an advantage in the search for food. The crabs may also come out during the day if it is raining or is moist since these conditions allow them to breathe more easily.

As mentioned above, they live exclusively on land and have been found over three and a half miles away from the ocean. Christmas Island in the Indian Ocean has the largest and best preserved population of coconut crabs in the world. On many of the islands in the Pacific and Indian Oceans, the coconut (robber) crabs are protected from being hunted and/or eaten with fines up to the equivalent of $3,000  U.S currency  per crab consumed.

Coconut or robber crabs are considered to be one of the most terrestrial of all the decapods and most aspects of its life are linked to a terrestrial existence. It will drown rapidly is sea water. Since as adults they cannot swim, coconut crabs must have colonized the Pacific and Indian Oceans islands either as larvae (a stage in their lives when they can swim) or on driftwood or other flotsam.

There are some islands, which are in easy distance for the coconut crab, and which have suitable habitat for the robber crab but are devoid of the crab. This is possibly due to the entire population being eaten to extinction by the people on the island.

The coconut crab, with its intimidating size and strength, holds a special position in the culture of many human societies that share its range. Admiring the strength of the robber crab many villagers will use the animal to guard their coconut plantations.

In Tokyo, especially if the robber crab is not fully grown, they may be sold for pets. However, the buyers cage must be strong enough that the animal cannot use its powerful claws to escape.

Should a coconut crab pinch a person, it will not only cause pain but it is unlikely to release its grip. Micronesians of the Line Islands (also known as the Equatorial Islands, which is a chain of eleven atolls and low coral islands in the central Pacific Ocean, south of the Hawaiian Islands, that stretches for 2350 kilometers in a northwest- southeast direction making it one of the longest island chains in the world) offer this tip to incite the crab to loosen its grip upon a human:

It may be interesting to know that in such a dilemma a gentle titillation of the under soft spots of the body with any light material will cause the crab to lose its hold.

The coconut crab is eaten by Southeast Asians and Pacific Islanders and is considered to be a delicacy as well as an aphrodisiac, tasting like lobster and crab meat. Most prized are the eggs inside the female and the fat in the abdomen. Robber crabs are cooked like other large crustaceans by boiling or steaming.

Different islands possess a variety of recipes, for example, coconut crab cooked in coconut milk. While the coconut crab itself is not innately poisonous, it may become so depending upon its diet and cases of coconut crab poisoning have occurred. It is believed that the poison comes from plant poisons, which would explain why some are poisonous and others are not.

However, the coconut crab is not a commercially significant species and isn’t usually sold. The coconut crab population has declined in several areas and has become extinct in response to both habitat loss and human predation.

It has become a worldwide protected species according to the IUCN (International Union for Conservation of Nature) Invertebrate Red Data Book. However, according to the IUCN Red List criteria, there is not enough data present to decide whether or not the robber crab is an endangered species. Therefore, it is provisionally listed as DD (data deficient) cautioning that this assessment is in need of update.

In some regions, there have been conservation management strategies affected (eg. minimum legal size restrictions as well as the prevention of capture of ovigerous (egg bearing) females has been banned in Guam, Vanuatu and the Federated States of Micronesia.

Juvenile coconut or robber crabs are vulnerable to introduced carnivores such as rats, pigs, and ants such as the yellow crazy ant.

The adult coconut crabs have only a few natural predators and significant numbers are eaten only by people. The adults have poor eyesight and detect enemies based on the ground vibrations. Overall it seems like the large human population has had a negative effect on the population of the coconut crab. In some areas populations are declining secondary to over-harvesting.

The coconut crab is protected in some areas like in the British Indian Ocean Territory with minimum sizes for taking and a protected breeding period.

Capt. Budd's Post Script

It has been written “a serious fisherman understands that success on the water begins long before the first cast. Success begins with the acquisition and organization of a well-stocked fishing box. The fisherman who wants to improve his catch must first improve his tools. In fishing, as in life, preparation is the better part of luck. “

So whether you charter, ride a head boat, run your own vessel, stay in the river, surf fish, or fish from shore or a bridge, there are fish to be caught. Fishing is not a matter of life or death, it I so much more important than that.

Tight lines, Captain Budd

This story and its contents are © copyright of NSB News LLC, New Smyrna Beach, Florida, owner of NSBNEWS.net and VolusiaNews.net.

 

About the Blogger

Capt. Budd Neviaser's picture

Capt. Budd Neviaser
Capt. Budd Neviaser is a life-long resident of New Smyrna Beach who has fished the Intracoastal waterways and the Atlantic Ocean most of his life.

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