Spiny lobsters are capable of communicating and sounding warning calls by means of stridulation - the rubbing together of two body parts to make a rasping noise. Unlike crickets that stridulate by rubbing their wings together, these sea bugs (as crustaceans are sometimes called) produce sounds by moving their antennae. This results in a soft tissue called the plectrum to stick, then glide, stick, then glide - cello players know what I mean - over a file near the eyes, creating a sound something like running your finger down a comb. An advantage of this is that they can make these noises even when they are in the vulnerable time after moulting.
Spiny lobsters are capable of communicating and sounding warning calls by means of stridulation - the rubbing together of two body parts to make a rasping noise. Unlike crickets that stridulate by rubbing their wings together, these sea bugs (as crustaceans are sometimes called) produce sounds by moving their antennae. This results in a soft tissue called the plectrum to stick, then glide, stick, then glide - cello players know what I mean - over a file near the eyes, creating a sound something like running your finger down a comb. An advantage of this is that they can make these noises even when they are in the vulnerable time after moulting.
Once threatened from overharvesting, pressure on ula poni was relaxed a bit in 2000 when a commercial lobster fishery in the NWHI was closed, and the area was designated a protected marine sanctuary under the Hawaiian Islands Coral Reef Ecosystem Reserve. Here in the MHI, ula cannot be taken May through August, females are off limits year round, and males must have a carapace length of three and one quarter inches. Spearing is prohibited. Check http://dlnr.hawaii.gov/dar/fishing/fishing-regulations/marine-invertebrates/ for updates. Consider that it takes a good eight years for the lobsters to reach maturity. And further consider that overharvesting by humans means less for young monk seals.
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No mistaking the barber pole stripes of the Banded Coral Shrimp, Stenopus hispidus, who offer their own version of a close shave. These colorful decapods belong to one the families of cleaner shrimp known for plucking ectoparasites and injured tissue off of fish such as tangs and morays. Setting up shop in tide pools and shallow waters (though they have been observed at greater depths), the banded coral shrimp often advertise their services by hanging upside-down in a crevice or reef ledges and waving their three pairs of very long, white antennae. These can be two to three times longer than the body of the shrimp, which is around two inches or so, and are used to palpate those in need of cleaning, as well as serving as sensors to help the shrimp move about at dusk, when it becomes active. They run the mom and pop shops of the reef- they are often found in pairs patrolling, defending, and servicing a square meter or so of the fish-rich waters. They'll also munch on other sea fare if cleaning clientele are low. In the reef ecosystem, these candy cane shrimp certainly have earned their stripes.
As I was hiking out to Ka'ena Point this morning for the The Sanctuary Ocean Humpback Whale Count, I came across this rough rider in one of the tidepools. It's ha 'uke 'uke, a.k.a. helmet or shingle urchin. Unlike their sharp and spiky brethren, this urchin's spines are modified into flattened shingles or tiles that create a beautiful, if briny mosaic, nicely accented by a "skirt" of flattened spines. The skirt spines are moveable, and underneath are lots and lots of tube feet. These features combine to give them the ability to hang tight in the full-contact wave impact zone where they forage for coralline algae (Porolithon), encrusting, rock-like algae that continue the reef building when corals reach sea level, and become to fragile to handle the pounding surf. Ha 'uke 'uke can get baseball-sized, and their yellow roe is considered onolicious to Hawaiians past and present. This one is truly taking cover - in more ways than one. The collector sea urchin, Tripneustes gratilla, known locally as hawa'e maoli, makes a fashion statement by covering its spines with limu, bits of shell, or other marine debris. This masking, or covering behavior is not fully understood but may be a means of protection from the rolling abrasion of wave action, or perhaps the harmful affects of UV light. Native to Hawaiian waters as well as the Indo-Pacific and the Red Sea, Tripneustes gratilla is found in shallow water down to about thirty meters, and can get to about five inches in test diameter. These guys are constant grazers, munching primarily on algae throughout the day and night. Good thing because these urchins have been recruited for an important job: taking the cover off of the corals in Kane'ohe Bay. Several invasive algae, including those in the genus Kappaphycus and Eucheuma denticulatum are blanketing the corals in a smothering embrace. Back in the 1970's, Kappaphycus species were intentionally introduced to bay for research and cultivation; these species produce kappa-carrageenan, which can be extracted and used in the food industry. Though the cultivation efforts were not successful, the algae was. As the seaweed spread, marching northward in the bay, efforts were made to remove it. Enter the Super Sucker, a marine vacuum used to hover up the alien goo. While thousands of pounds of algae were removed, it rebounded quickly. And that's where Tripneustes gratilla comes in. Researchers at the Anuenue Fisheries Research Center on Sand Island developed techniques to breed the sea urchins, 100,000 of which were placed on the reef to do what they do best: eat the algae that is left behind. And eat they do. According to Dr. Eric Conklin, the Nature Conservancy’s Hawai‘i marine science director: “On reefs where we have placed the urchins, algae re-growth after a year is about five percent....On reefs without urchins, algae can re-grow within six months.” The Conservancy, in tandem with the State Division of Aquatic Resources, plan on releasing 200,000 urchins in 2014. ʻAi ā manō!! Today I hand over the authorship of the post to a seventh-grade student of mine, Chloe Loughridge. She has an on-going interest in the Hawaiian Bobtail Squid, a native of Midway and the MHI. Her curiosity was sparked when she encountered some researchers looking for this member of the family Sepiolidae in the shallow waters off Oahu. Since then she has been rearing and studying this tiny wonder that is known for its remarkable ability to turn on a cloak of invisibility. In the deep of night, when shadows come out to haunt the beaches, and the ocean becomes a pool of never-ending darkness, a silent hunter glides soundlessly through midnight, moon-glossed waters. The vigilant predator settles gently on the sandy bottom of the sea while its eyes dilate and probe the darkness for its secrets. This little creature, the Hawaiian Bobtail Squid, also known as Euprymna scolopes, is delicate, sensitive, and endemic to our islands. Although we don’t know all of its secrets, the small Bobtail Squid provides huge possibilities for scientists. Such a creature could be used to solve problems plaguing our world today, and it lives right in our own backyard. One of the squid’s more prominent characteristics is the fact that it "glows" in the dark, which is quite handy considering that it is nocturnal. The Bobtail Squid is able to use bioluminescent bacteria (Vibrio fischeri) to help it glow, thereby making it possible for the squid to erase its own shadow. Using a cavity on its underside, the squid sweeps in Vibrio fischeri from the ocean with the help of cilia, or small hair-like structures. The Bobtail Squid is able to cultivate these bacteria, which after reaching a certain concentration, begin to glow in the squid’s light organ. The squid can control the light intensity of its bio-flashlight simply by controlling the amount of oxygen that the bacteria in the light organ receive. This light organ is located near the ink sack of the squid, and the muscles in charge of controlling the amount of ink that the squid releases are also in charge of controlling the amount of light that the squid emits. In other words, the Bobtail Squid has a built-in, living flashlight on the underside of its belly. In this way, the Bobtail Squid simply blends into the starry canopy of night sky above, monitoring its light output to match the moonlight above so that it is practically invisible to any predator that may be on the hunt. It also is invisible to its own prey. Scientists from around the world are interested in this little creature’s symbiotic relationship with the bioluminescent bacteria Vibrio fischeri, and every year, researchers are sent to collect batches of Bobtail Squid from our very own waters. This is no surprise however, because the squid’s ability to cultivate and sustain such bacteria could be helpful in cancer research—bioluminescent bacteria like Vibrio fischeri could be used to mark cancer cells. By understanding the symbiotic relationship between the Bobtail Squid and its bacteria, we may also be able to understand more about our own relationships with the good bacteria in our bodies as well. So, really, protecting the Bobtail Squid is not just protecting another sea creature, but it is preserving and protecting future opportunities for ourselves.
Permit me a bit of latitude for today's post. As I am on holiday visiting family in Rhode Island, I am getting reacquainted with the creatures of the Northeast woodlands, and of course, the Atlantic. And when I ran across this "living fossil" down at the beach the other day, I knew I had to write a post about the critter whose story is as old as the hills, yet plays a crucial, but under-appreciated role in modern medicine. This is Limulus polyphemus, the Atlantic horseshoe crab, with three related species residing in East and Southeast Asia. As with other Arthropods, it is characterized by jointed appendages, a segmented body and an exoskeleton. The three main classes of Arthropods are the Insects, Crustaceans, and Arachnids, but the horseshoe crab merits its own class, called Merostomata, a term which refers to the positioning of the mouth at the center of it's ten legs. They also have a long, whip-like tail which gives it a menacing appearance, but serves as a means of flipping the crab upright in the event it is overturned. Docile creatures, horseshoe crabs are primarily concerned with snuffling up worms and molluscs from the sandy or muddy ocean shallows. They are loaded with eyes - a pair of lateral eyes as well as five other eyes are located on the top of the shell, photoreceptors line the tail, and ventral eyes are found near the mouth. This gives them light and UV sensitivity, keeping them in rhythm with the cycles of the days and nights, helping them find a mate, and serving to orient them, which helps when they swim upside down, angled a bit from horizontal. Few people realize, though, that the horseshoe crab may have saved their life, or that of a loved one. And it's done in cold blood. That's right: it's the horseshoe crab blood that is so important. First, it's blue, due to the presence of hemocyanin, but that's not the special thing. You see, horseshoe crab blood has certain components that are bacterial killers: clotting when they come in contact with bacteria endotoxins, binding with, and then deactivating them. Meanwhile, in labs around the world, the manufacturers of intravenous drugs, vaccines, and any medical device that needs to be implanted need to be sure their products are free of endotoxins, so that we can receive treatment without fear of potentially fatal sepsis. And so, the two worlds meet: an extract made from the horseshoe crab's blood, called LAL, is used to ensure the sterility of their products. If, for example, a vaccine batch tested with LAL gets slurry and clotty, it's not sterile, and is therefore discarded. To obtain this life-saving extract, the crabs are collected, transported, and bled (about 1/3 of their blood is removed). Happily, they can be returned to the ocean, though a certain percentage do not survive the ordeal. The importance of this marine invertebrate to the medical field may mean that more research is done to better understand and protect their populations.
Seeing as these creatures are soft and slow, and without the spiny protection of their cousins, you might think they are easy pickings, but sea cucumbers have a arsenal of defenses. Their squishable bodies allow them to tuck under rocks and in small crevices. Some simply taste bad due to noxious chemicals in their skin. But here's something unique: some cukes expel Cuvierian tubules from their anus - sticky threads that entangle predators, and may be accompanied by the release of a toxin called holothurin. Take that! And just in case, some sea cukes can also eviscerate, which essentially means that they can expel some of their insides, sneak away, and then spend a good portion of time regenerating.
They're innocent looking enough. Just some marine snails in conical hats, clamped to the rocks in the intertidal zone, and doing their part for the ecosystem by keeping the fuzzy algae in check. But the saying, He ia make ka opihi - the opihi is the fish of death, serves as a reminder that picking 'opihi for their tasty flesh is a risky business. While their shape and strong muscular foot allows them to hold fast through pounding surf, the tidal surge can be downright frightening for the 'opihi harvester. There are three species of 'opihi here: the blackfoot, 'opihi makaiauli; the yellowfoot, 'opihi alinalina; and the kneecap 'opihi, or koele. The blackfoot inhabits areas closest to shore, the kneecap likes it a bit deeper, and the yellowfoot prefers it where the surf is roughest. Despite the difficulties for the collector, 'opihi numbers have declined significantly due mainly to overharvesting. A gallon of 'opihi can go for as much as $200. Presently, the 'Opihi Partnership, spearheaded by the Nature Conservancy, is working to gather baseline data about 'opihi populations near Maui and Kaho'olawe. Others are attempting to raise 'opihi using aquaculture techniques to relieve pressure on this humble limpet. On a side note, genetic studies have been underway by researchers at the Hawaii Institute of Marine Biology. They have determined that each island has it's own unique populations of 'opihi. 'Opihi are similar to other marine snails in that they have gills, a mouth tube, a head with tentacles, and a strong muscular foot. They are known to create shallow depressions in the rock which becomes their "base camp." After venturing out for feeding, they return to the snugly-fitting base camp for extra gripping power. Though they do not permanently attach themselves like barnacles do, they are the "super gluers" of the snails and may be near impossible to pry off once a failed attempt to pluck them has been made. Their low profile also helps them to remain steadfast through wave action and the ribbing of the shell allows water to drain off easily. Traditionally, 'opihi were also used as scrapers for taro, and for jewelry.
Dotting the coastlines of several of the MHI are anchialine pools, formed when freshwater percolates through the ground and meets up with salty water that enters through subterranean cracks and fissures in lava or limestone. The result is a landlocked body of water with secret passages to the sea. The water is stratified, layered with salty, denser water at deeper levels, and brackish to fresh water near the surface. Salinity levels in these pools are also influenced by tidal changes and solar intensity. While this habitat would seem a rather challenging place to live, a surprising diversity of creatures call it home, including the poster child for Hawaii's anchilaine pools: Halocaridina rubra. The 'opae 'ula, a.k.a Hawaiian red shrimp, or volcano shrimp, is a little thing, just up to a half inch in length. These are the shrimp that you may see for sale in air-tight "ecospheres", and while their trade has brought attention to this otherwise little-known decapod, their fates are literally sealed.
In their natural environment they feed on algal and bacterial mats within the pool, scraping and filtering these with hair-like structures on their chelipeds. Detritus and plankton may also be consumed. 'Opae 'ula were used by early Hawaiians in their fish ponds as food for larger fish, such as 'opelu, and they are also a favorite food of seahorses. They are unusually long-lived, with estimates from 10-15 years in he wild, and reproduce underground. Hawaii is thought to have approximately 650 anchialine pools, with the vast majority of them found on the island of Hawai’i. Much remains to be learned about these pools and the creatures that live there. In the meantime, it is important to respect these unusual habitats, leaving them undisturbed and free from alien species, such as guppies, tilapia and mosquito fish.
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