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module_6_discussion_responses.docxModule 6 Discussion 1 Life without a Backbone
Response 1
GARY BONE
Spiny King Crab
There are approximately 120 species of king crab thriving throughout the world’s oceans. I’ve chosen to research the spiny king crap species, which is also known as the California king crab, or Paralithodes californiensis. Primarily found near the continental shelf, spiny king crab prefer depths greater than 200 feet below the surface, some have even been observed at 2,400 feet below (Kaine, nd). Spiny king crabs are a unique species in that they have many spines covering the majority of their abdomen, which protects the crab from predators and provides relative camouflage. Like most crabs, the spiny king crab has three pairs of walking legs and one pair of claws. There is also a smaller fifth pair of legs under the crabs body used to clean the gills.
Predators of the spiny king crab include humans, octopuses, and other crabs as well. They mostly eat dead animals that fall from the ocean above them, however they are also known to prey on smaller crabs when food is scarce. Reproducing once per year, the female spiny king crab incubates fertilized eggs for 11 months before hatching them in shallow water to avoid predators (Wada, 1997). The shell of the spiny king crab is shed many times in the first few years of its life. As an adult, they shed around once every year or two years, reaching up to 6 inches in diameter. Spiny king crabs can live up to 30 years old, and at this point in their life cycle, their main predators are humans.
Kaine, Rachel (nd) Fast Facts on the Spiny King Crab. Retrieved from http://animals.mom.me/fast-spiny-king-crab-7803.html
Wada, Satoshi (1997) Observations on the Reproductive Behavior of the Spiny King Crab Paralithodes brevipes. Retrieved from http://ci.nii.ac.jp/els/110002694429.pdf?id=ART0002970302&type=pdf&lang=en&host=cinii&order_no=&ppv_type=0&lang_sw=&no=1438815081&cp =
Response 2
Rhalynn
Red Sea Cucumber
The parastichopus californicus, also known as the red sea cucumber, is a marine invertebrate found in the Pacific Ocean from the Bering Sea to Mexico. It prefers areas with harder bottoms, such as gravel or ground up shells, as well as moderate currents. The cucumber also seems to be found in areas where freshwater is introduced to the ocean through runoff.
The diet of the P. californicus consists of plankton, as well as the waste products and dead bodies of other marine animals.
These sea cucumbers breed during the summer, with the females laying eggs to be fertilized by the males’ sperm outside of the body of the female. After fertilization, the eggs become larvae, then spend anywhere from seven to thirteen weeks in a plegic phase. When the cucumbers reach ages between four to eight years, they are considered mature, and can live up to twelve years.
The most common predators of sea cucumbers are sea stars. Fish, crabs, and sea otters have also been known to prey upon the red sea cucumber.
Interestingly, these sea cucumbers can take in nutrients by “inhaling” water through its anus, into respiratory trees located there. After a few inhales, they can quickly and violently expel the water from these “water lungs”.
Reference:
Red Sea Cucumber (parastichopus californicus) Species Profile. Retrieved 6 August 2015 from http://www.adfg.alaska.gov/index.cfm?adfg=redseacucumber.main
Response 3
Alissa
Wolf Eel
The Anarrhichthys ocellatus, otherwise known as the Wolf Eel. The wolf eel can be commonly found in the North Pacific in the Sea of Okhotsk and the Sea of Japan all the way to the Krenitzen Islands located in the Aleutian chain as well as the Imperial Beach located in Southern California, United States of America. The Wolf Eel can reach a depth of 1-226 m. The max length they can reach is up to 240cm and they can reach up to 18.4 kg in weight. The adult Wolf Eel's will live in the rocks in the sub tidal areas. They will stay in these area's until they are driven out by either a larger wolf eel or even a large octopus. They feed on the hard shelled invertebrates and other fish as well as crabs, sand dollars and sea urchins. Male and females can wrap their bodies around their entire mass of eggs to keep the eggs in place. This will also deter predators to attack. Predators to the wolf eel's are the harbor seals. The young wolf eel's are prey to rockfish as well. When "courting" a female they will butt their head on the females abdomen and then wrap around her and fertilize her eggs as they are extruded from her. The eggs are not left alone, one parent at a time will leave to feed then return so the other parent can feed. The female well rotate the eggs periodically up until they hatch. The parents will pair for life.
Fishbase. "Anarrhichthys ocellatus, Wolf-eel." Retrieved from http://fishbase.org/summary/3813
Monterey Bay Aquarium. "Wolf Eel" retrieved from http://www.montereybayaquarium.org/animal-guide/fishes/wolf-eel
Module 6 Discussion 2 Backbones At Sea
Response 1
Shawn
Common Stingray
For this discussion we will be talking about marine vertebrates. By definition a marine vertebrate is any multi-cellular organism that has a spine or vertebral column. All vertebrates follow a general structural plan wherein the mouth of the organism is near the front while the anus is towards the back. (Marine Vertebrates – Vertebrata, 2015) I chose to research the Dasyatis pastinaca or common stingray. Visually speaking the ray has a rhomboid shaped disc with a straight anterior margin and a pointed snout with a small protrusion. The tail is less than twice the disc length, the dorsal finfold is short, and the ventral finfold is short and deep. The dorsum is grey to golden brown and the ventrum is off white with a grey/brown margin. Primarily the stingray lives in the eastern Atlantic, Mediterranean, and Black Sea and is found over sandy and muddy bottoms from shallow waters to a depth of approximately 200 meters. This animal can reach a maximum reported size of 140 cm disc width and 250 cm total length. Regarding birthing, females reproduce twice a year but the age of reproduction is unknown but gestation is observed to be around 4 months. A litter consists of 4 to 7 pups. The stingray can feed on crustaceans, cephalopods, clams, polychaetes and fish but generally speaking crustaceans make up 99% of all stingray’s diets. (Dasyatis pastinaca, 2015) The ray spends much of its time resting on the sand or under rocky ledges. (Common Stingray, 2015)
References:
Marine Vertebrates - Vertebrata. (2015). Retrieved August 5, 2015 from http://www.seawater.no/fauna/chordata/Vertebrata.html
Dasyatis pastinaca. (2015). Retrieved August 5, 2015 from http://www.iucnredlist.org/details/161453/0
Common Stingray. (2015). Retrieved August 5, 2015 from http://www.elasmodiver.com/CommonStingray.htm
Response 2
Henry
Response 3
Edwin
The Hammer head shark has an oddly shaped head that uses improved sensors to find prey and scan the ocean floor. The head is wide and looks like a hammer at both ends. The body is light grey and white underneath but most have a greenish type tint. The hammerhead shark can grow up to 20 feet long. The hammer head uses a sensor organ called the ampullae of leronzini that allow it to detect the electrical fields of its prey. The Hammerhead preys on stingray’s small fish and smaller sharks. The Hammerhead can weigh up to 1,000 lbs. The Hammerhead can be found in tropical waters worldwide, far offshore or near shore during summer migrations seeking cooler waters. The hammer head shark is normally harmless to humans but its size presents a threat. Female hammerheads can give birth to 20-40 pups at one time. The hammerheads have a high survival rate in comparison to other sharks.
Hammer head shark facts found here http://animals.nationalgeographic.com/animals/fish/hammerhead-shark/
Hammerhead information found here
http://www.sharks-world.com/hammerhead_shark/
