The Diamondback Squid Of Nanumanga, Tuvalu
This months article series, will discuss the palmate octopus of Nanumanga, Tuvalu. Nanumanga is an island in the South Pacific, it belongs to the country of Tuvalu. It has a very small population as it is only 1 square mile in total. There are approximately 491 people who inhabit the island. It is approximately 3556.56 Nautical / Marine Miles (4092.816154 miles or 6586.74912 kilometers) from mainland Asia, specifically the country of China. It is also approximately 1706.54 Nautical / Marine Miles (1963.851159 miles or 3160.51208 kilometers) from Australia. The island is known for their beautiful coral reefs & scuba diving experiences. The country of Tuvalu is most well known for being built on massive coral atolls, with a large percentage of their ocean having some presence of living coral. This attracts many other marine species which in turn diversifies the area. The area also has a quite favourable climate, with it being quite warm for the entire year. The oceanic temperature changes very slightly through the seasons, so this may attract species that require lots of prey as prey will be available year round. The species that are attracted, form new ecological structures & make others more feasible, an example where this is seen is seagrass meadows. One of the species that is attracted to the area, is known as the Thysanoteuthis rhombus (diamondback squid). It is a species of squid which inhabits the surrounding waters of the island. The diamondback squid is a small squid usually pinkish in colour, that is found throughout the South Pacific as well as the Atlantic. They are not venomous & usually do not attack humans. This species is found in semi-high density around the island. The reason for this most likely is the favourable climate & the high amount of prey. It is easily identifiable as it has large fins that run the approximate length of the mantle. The fins are most likely the reason for the name “diamondback” as their fins appear similar to a cut diamond. It is quite easy to identify them by sex as well, as the females may be up to a full meter in length while the males may be as small as a few centimeters. In this article we will discuss the life of the diamondback squid, the mating procedures, tactics, practices, & cycles of the diamondback squid, the distribution of the diamondback squid , & finally the scientific detailings of the diamondback squid.
The Life Of The Diamondback Squid
The Diamondback squid was first described in the year 1857 by Frans Herman Troschel, a german zoologist. The first work that they were described in is unclear. It is also unclear how exactly this species was discovered. The diamondback squid differs wildly in size between males & females. The species may grow to be up to 100 centimeters (1 meter or 3.28084 feet). However it rare that they will grow to be this size, it is more likely that they will be 85 centimeters long & lower (0.85 meters or 2.78871 feet). They may have a maximum weight of 30 kilograms, however they average at 20 kilograms (66.1387 pounds or 44.0925 pounds) between both sexes. The life span of the diamondback squid is approximately 1 year to 1 year & 3 months. As a species, they do not seem to exhibit any more intelligence then an average squid species. Squids as a whole are incredibly intelligent. They demonstrate problem solving skills. They also occasionally use their tentacles to pull themselves into small crevices. Much like octopi in a way. They also seem to be able to recognize humans & to maintain a sense of identity. It is incredibly hard to tell when this species started existing. However, we do know that the oldest squid species that we know of, began existing at least 328 million years ago. This narrows it down considerably. They tend to not interact with humans & keep their distance. However they are known for occasionally jumping into boats. They also do not seem to show aggression towards humans. They have been captured before & are often sold in Japan & places around Japan. They are migratory creatures & do not seem to stay in one place. However it is a slow migration. They do not seem to be territorial or have a sense of territory. It is unknown how solitary they are & how much they tolerate each other, but they do tolerate each other. This is seen in that they will pair with each other. Pairs of monogamous diamondback will gather in groups of up to 20. They have many natural predators, most commonly sharks, whales, Dolphin fish, lancet fish, certain species of tuna & swordfish. They are somehow, able to make powerful contractions using their mantle in order to escape predators & other threats. These species will all consume diamondback squid if given the chance. A strange behaviour of the diamondback squid, is that they will slowly go deeper into the ocean over the course of their lives. Juveniles will usually stay at subsurface levels for this sector of their lives. Then once they mature, they will begin venturing deeper & deeper. This makes it so that the majority of adults are found in the Mesopelagic zone, & most juveniles are found on the surface. It had been proven, that most adults beyond 400 meters deep (1312.34 feet deep) mostly consume nonactive fish. Most squid on the top consume crustaceans, other cephalopods, & fish of various species. The squid on the top will usually feed in the day time, while the squid in the mesopelagic zone are nocturnal feeders. It is unknown how much it consumes per day. Since it swims rather slowly & usually does not seem like it has that high of a metabolism. It is also unclear as to how exactly it hunts. They are not very active swimmers, they are able to propel themselves slowly using their large fins. It is not exactly clear at what speeds the diamondback squid is capable of swimming at. It unknown as to how exactly they are able to sleep. The diamondback squid is a nice light redish-pink. They have incredibly long mantles with triangular fins & at the bottom they have a set of stubby tentacles.
The Mating Cycles, Practices Tactics, & Procedures Of The Diamondback Squid
The Diamondback squid mate via sexual reproduction. They are the only known cephalopod species that are monogamous. The females will mature at a mantle length of 500 to 650 millimeters (50 to 65 centimeters or 19.685 to 25.5906 inches). The males will mature at 400 millimeters to 550 millimeters (40 to 55 centimeters or 15.748 to 21.6535 inches). However, they will mate prematurely & will usually do so at a mantle length of less then 100 millimeters (10 centimeters or 3.93701 inches). They are not hermaphroditic & cannot change sexes. Mating occurs in a head to head position, which in the male will use his hectocotylus to attach to the females buccal membrane to transfer his spermatophores. After this the female will produce secretions of an egg mass from her nidamental glands. The eggs will enter the water & will begin to swell. This swollen egg mass will then be molded into a cylinder by the female, after which the females oviductal glands will begin to form two mucous threads, both of which will be containing a double row of eggs. She will then fuse them into a single cord.
The fused cord then exits through into the water through a funnel where the eggs are met & fertilized with the spermatozoa from the males seminal receptacles that were attached to the female's buccal membrane. The fertilized egg cord is then wound by the female onto the cylinder. A female can produce 8 to 12 masses if properly utilizing its vitelline oocytes. After this, it seems as if the female will simply swim off, leaving the babies to fend for themselves. It is unknown exactly how many fertilized eggs are produced in the end. It is also unclear how long it takes for the eggs to hatch. It is also unclear exactly how many times the female & male will engage in this action throughout their relationship. It seems, that there will be a 2-3 month block in their relationship where they will engage in this action, then will not engage for the rest of their lives.
The Distribution Of The Diamondback Squid
The diamondback squid is found throughout the majority of most tropical & subtropical regions of the world. They are found in approximately 101 countries throughout the world. They are found throughout the Caribbean, the North Pacific, the South Pacific & all through Africa. They prefer warmer temperatures & seem to die in temperatures below 15° celsius (59° Fahrenheit). This is also why they usually prefer to stay in the subsurface area. These tropical areas that they are found in, are usually quite shallow. For example, they are found quite commonly throughout the sea of japan, in the center of the sea of Japan, there is a very shallow area known as Yamato bank. This is most likely very appealing as Yamato bank is both warm & shallow. They are found around 6 of the 7 continents on earth as of publication. They do not seem to be decreasing in population, so they can be expected to make their presence well known. It is also hard to say if there has been a migrational trend or not, as we are not entirely sure how long they existed for in these areas.
The Scientific Detailings Of The Diamondback Squid
Without a doubt, one of the most interesting things about squids is their ability to produce ink. They produce this ink a means of defence. By producing this ink, their attacker will be blinded as it obscures their vision, allowing the squid to make a swift escape. This is not a common technique of defence seen in oceanic species. The diamondback squid in particular has a reddish brown colour of ink. Chemically speaking, the squids ink contains melanin, enzymes polysaccharides, catecholamines, metals cadmium, lead, & copper, as well as amino acids, such as glutamate, taurine, alanine, leucine, & aspartic acid. The ink is stored in an ink sack in the center of the mantle next to the liver. The squid releases this ink through the siphon, which is located just below the mantle on the opposite side of the mantle that the eyes are upon. Another interesting thing about squids, is that they are completely compressible aside from their beak. Whatever crevice that the beak can fit through, the squid can fit through. It is proven that a squid can fit through an area that is a quarter of the size of the squid. Their beak is their only real hard area on their body, with the rest being compressible. The beak is located underneath the mantle & at the base of the tentacles. This species of squid is not venomous in any capacity. The squid has 3 hearts, 2 branchial & one systemic. The systemic heart rests in the middle of the mantle. The gill heart rests slightly further up. The gill heart takes in oxygen in the blood, & then sends the oxygenized blood to the systemic heart. The systemic heart will then send the blood about the squids body. Their brain rests in their lower mantle. However, this brain is not how we think of it traditionally. It is rather small & does not control much. As stated in our previous article on the European squid, squids do have small brains, they do not have a central nervous system. They do not have a centralized brain that controls the body as humans do. Their neurons are in various clusters around their body. These clusters are known as ganglia. These clusters will control various parts of the body. They also have very are very strange when it comes neuroscience. This is best said by Jade Zee, A professor at northeastern university. She says & we quote “We humans have white matter, which causes electrical signals to travel much, much faster in our neurons. Invertebrates don’t have that. So the invertebrate solution, if you want electrical signals travel faster, is to have a wider diameter axon of a neuron. The very first action potentials were recorded in what’s called the squid giant axon. It’s about a millimeter in diameter, which I know still sounds small, but that’s actually really, really big compared to other nerves.”. Their blood is also blue instead of red. The reason for this is due to a copper rich protein known as Hemocyanin existing in their blood. The existence of this protein in their blood causes their blood to be blue. This is very similar to the iron in Hemoglobin in human blood. This blue blood exists in all cephalopods. This blue blood can be used a pigment if used properly. Their phylum is known as Mollusca. Mollusca is the 2nd largest phylum, just behind Arthopoda. Mollusca is however the largest marine phylum as it comprises approximately 23% of all documented marine species. The three most commonly found features defining modern species categorized under molluscs are the following: a mantle with a significant cavity used for breathing & excretion, the presence of a radula, and the structure of the nervous system. Their class is Cephalopoda. This class includes almost all species of cuttlefish, octopi, squid, & nautilus. Their order is Octopoda. This order contains the same types of species as Cephalopoda. A universal characteristic of this order is that all species classified under this are invertebrates, as well as the presence of arms or tentacles. Their order is Oegopsida, an order of squid, similar to Myopsida. A few universal characteristics of squid under this order is that they have a mantle without tentacle pockets, their eyes lack a corneal covering, & they have buccal supports without suckers. Their family is Thysanoteuthidae, a family comprised of just 1 species, however this is may change. Their genus is Thysanoteuthis, which is a genus of squid. Once again, this genus only contains Thysanoteuthis rhombus. Their binomial name is Thysanoteuthis rhombus.
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