Atlantic Stingray (Dasyatis Sabina) Essay Example | Topics and Well Written Essays - 1000 words

Atlantic Stingray (Dasyatis Sabina) - Essay Example DESCRIPTION: The Atlantic stingray, Dasyatis sabina (Lesueur 1824) has a disc shape typical to all stingrays, and it is one of the smallest in its family (Piercy). It has a spade-like body form, having a relatively long snout and a long, slender, whip-like tail (McEachran 177). It has a brown to or yellowish coloration on the dorsal side which goes lighter near the edges and white or light gray on the ventral side (Passareli). To distinguish it from other similar genera, characters such as a certain ratio of snout length (25-27% of the total disc width) and snout angle (maximum of 107-122Â °) confirm its species identity. The outer corners of the disc body are broadly-rounded, while the posterior margin is moderately convex. The floor of the mouth has a row of three stout papillae, and has 28-36 rows of teeth. Both males and females have similar-looking teeth, rounded and having flat, blunt surfaces, except during mating season when the males develop sharper and narrower sets for cl asping the female during copulation (Tricas 224). The tail is similar to a whip, long and tapered with a barb measuring up to 25% of the disc width, and this modified scale secretes venom from both the dorsal and ventral sides (Passareli). Maximum disc size could reach up to 12.8 inches in males and 14.6 inches in females living in coastal or brackish lagoons, while for freshwater rays sizes reach up to 8.7 inches for females and 8.3 inches for males. Like other members of the cartilaginous fishes, the Atlantic stingray is capable of generating weak electrical fields, both in finding prey and females at the benthic zone. FOOD: Food can be primarily anything that can be caught near the bottom of the habitat or the benthic zone, and these are mostly polychaetes, crustaceans, and bony fishes (McEachran 177). Other reported organisms that are hunted include bivalves, tube anemones, clams, nereid worms, and amphipods (Passareli). HABITAT: Atlantic stingrays live in brackish benthic water systems, where the saltwater meets fresh waters coming from estuaries (Johnson 75). There is a preference for sandy bottoms but with water depths less than 25m (Piercy). These fish migrate from brackish waters to fresh waters and back again, depending on the climate of the areas, which shows that they have varying but wide degrees of salt tolerance. Water temperature ranges for the species is around 24.5Â °C-31.0Â °C (Wallman 259). MATING: Initial studies mentioned that Atlantic stingray mating seasons start from late March when ovulation in females begin and lasts up to July (Johnson 74). Later studies indicated that the mating season could last as long as nine months, from August to April of the following year (Tricas 209). Changes seen in the males such as sharper teeth happen during the breeding season in order to clasp the females during copulation, which is comparable to some mating behavior of related species like in some sharks. PREDATORS: Predators depend on the location of the Atlantic stingrays. In brackish to coastal areas, sharks such as white shark, tiger sharks and bull sharks are the major predators (Passareli). In freshwaters, alligators are reported to be the major stingray predators. BEHAVIOR: Atlantic stingrays are non-aggressive fish, and only attack when stepped on (Passareli). When hunting for food, rays swim slowly near