The Life of Seahorse - Essay Example

Marine Biology (Seahorse) Hippocampus ingens Outline Taxonomy 2) 3) Reproduction 4) Habitat 5) Current ecological problems, associated with seahorse Seahorse is probably the most mythologized animal, as its description can be found even in Greek legends and mythological texts, which hold that seahorses led Neptune's chariot, and sailors depicted these animals on their ships and bodies as they were believed to bring good luck and sailing weather (Myers, 1960). In fact, all seahorse species have already been examined in scientific literature, and their unique supernatural abilities quite long ago turned out a total fairy tale. In traditional biology, seahorses are identified as the representatives of Animal kingdom, Chordata phylum, Osteichthyes class, Atherinomorphia superorder, Gasterosteiformes order, Syngnathidae family, Hippocampus genus. Nowadays Hippocampus counts almost 20 species, including Hippocampus ingens (dwelling in Pacific ocean), Hippocampus reidi (longsnout seahorse), Hippcampus erectus (Northern seahorse), Hippocampus kuda (the yeallow seahorse) and many others. "Despite previous taxonomic classifications as insects and amphibians, they are fish, cousins to pipefish and sea dragons, from the family Syngnathidae, Greek for "fused jaws." Like most fish they have gills for breathing, a swimbladder for buoyancy, two pectoral fins for balance, and dorsal fins that flutter as much as 35 times per second" (Arrigoni, 1989, p.358). As one can see at the picture below, seahorses have no teeth, caudal fin for speed and stomach, as the last part is replaced in seahorse morphology by enormous tail, used for great speed development. In spite of their beauty and grace, seahorses serve as the Frankensteins of underwater 'society', as they are apparently made of various animals' body parts. As their name shows, seahorses have vertical body and horse's head, situated perpendicularly to the body. Furthermore, seahorse has a kind of crown on its head, and what is most amazing about this body part is the fact that this coronet is as unique as human DNA (Lourie et al, 1999). In addition, their body armor is quite firm and resembles aardvark's brigandine, but this body plate has many shapes and colors (white, pink, gray and so on), depending on the species and individual characteristics (Myers, 1960). Their snout and body armor resemble an aardvark's.In terms of their ability to change coloration, seahorses resemble chameleons, as they also mimicre in accordance with the environment colors. "Also with lizards, they share independently moving eyes, assisting both survival and predation tactics. They've borrowed prehensile tails from monkeys, and made a major alteration to the brood pouch of marsupials, with male seahorses nurturing their young" (Lourie et al, 1999, p.231). (from Long, 1995, p.192) As for the reproduction and prenatal behavior, seahorses are distinguished due to the unusual behavior of male individuals, or so-called mating rituals, which are typically attributed to the animal classes as well as to some fish species. Moreover, male individuals usually carry and accept fertilized eggs to order to extort brood in future, as both females and females have prolactin, the hormone that allows this form of hermaphroditic reproduction (Arrigoni, 1989). "Individuals reach sexual maturity by the next breeding season following birth, at the ripe age of three months to a year, depending on size of the species. Breeding seasons vary by species and may be restricted by cooler weather or monsoons, though some go year-round" (ibid, p.188). In particular, H. ingens is able to breed at 12 months, and it is important to note that couples are monogamous as a rule. During the breeding season, pair bonds are encouraged by daily greetings, when individuals prepare an entire performance for each other: change colors, dance and then promenade together by entwining their tails. Furthermore, the female individual puts its oviopositor into the male's brood pouch in order to transmit her eggs there so that the male fertilizes them. Furthermore, the eggs remain in the pouch that serves as a womb because of specific tissue structure. "It is interesting to note that despite the apparent role reversal, it does not extend to widely held animal behavior theory regarding competition" (ibid, p.189).Male individuals are more aggressive comparing to females, and might even be violent in approaching to available female. The number of newborns varies from 5 to 1500 (ibid), their size is about 7-12 mm, and during 10-40 postnatal days, the male nurtures the offspring as well as provides the female with necessary nutrition (ibid), but Long also states that both coupled individuals participate in their newborn's development (Long, 1995). Using its tail as an anchor and its mimicry as camouflage among corals and sea plants, seahorse successfully predates within underwater world, in particular, because of its ravenous appetite and ability of sitting and waiting for hours until prospective victim becomes more vulnerable. In addition, the seahorse's eyes move independently from each other, which allows them to detect food at different sides. "With a jerk of the head, any unsuspecting fish, larvae, plankton, or other living thing small enough to fit, can be sucked into the powerful snout. In the laboratory however, H. ingens has proven to be a picky eater" (Lourie et al, 1999, p.341). Furthermore, the appropriate research suggests that insufficient lighting negatively influences the seahorse's hunt, but this species is nocturnal - that's why its habitat is underwater depth (ibid). "This may have been a necessary behavior modification due to increased daytime fishing activity since seahorses are often captured as a by-product of shrimp trawling" (ibid, p.342). Nevertheless, seahorses are capable of processing only tiny food pieces ( like small crustacea or fish fry), as their digestion system allows only sucking in edibles with the long snout. Because of their temperature and water preferences, seahorses are distributed in tropical and temperate zones, through saltwater brackish water territories. Dwellings commonly favored by seahorses are coral reefs and sea grass (Breder and Edgarton, 1942). The places of seahorse distribution include coastal territories of the Pacific Ocean, Wtsern Atlantic Ocean and Indopacific Region. Unfortunately the Indopacific species arenow experiencing increasingly greater impact from seahorse traders' side (Lourie et al, 1999). In fact, seahorses do not enjoy high fertility or low birth mortality (in many cases it reaches 99 per cent), so the average seahorse of able to produce about 200 offspring throughout the 5-year- lifespan (ibid), whereas the pace of the new business is growing annually. Furthermore, monogamous 'lifestyle' deteriorates the situation, because it would take of the individual much time until it finds appropriate partner. The research suggests that "Eastern medicines dry and grind them up for use as an aphrodisiac or treat symptoms ranging from impotence, asthma, fractures, and diseases of the heart, kidneys, skin and thyroid (Lourie et al 1999). At least 47 countries participate in the legal trade of seahorses, either living or dead (ibid, p.380). The United States, in turn, exports and imports these products, whereas the fact that seahorse makes significant contribution into ecological system (balances fish proportions and removes weaker crustacea species ) , is to great extent overlooked. These animals thus should be protected at biological, ecological and medical levels, as in future they will be needed for vaccines or vital medications (ibid). Reference list Arrigoni, W. Seahorses. Sea Frontiers, 1989, 35(6): 358-65. Breder, C.M., Jr. and H.E. Edgarton. An analysis of the locomotion of the seahorse, hippocampus, by means of high speed cinematography. Annals of the New York Academy of Sciences, 1942, 43: 145-172. Long, J.A. The Rise of Fishes. Baltimore and London. The Johns Hopkins University Press, 1995. Lourie, S.A., A.C.J. Vincent, H.J. Hall. Seahorses: An Identification Guide to the World's Species and Their Conservation. London, UK. Project Seahorse, 1999. Myers, G. The Sea-Horse and Its Relatives. Copeia, 1960, 1(3), p. 78 Read More