Pacific spiny dogfish

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The Pacific spiny dogfish or northern Pacific spiny dogfish (Squalus suckleyi) is a common species of the Squalidae (dogfish) family of sharks. Dogfish is known to be one of the most abundant species of sharks in the world. Squalus suckleyi was previously thought to be identical to the Squalus acanthias species. Although, the two species have different genetics, body structures, and morphological features. These differences between the two animals led to form a new species of dogfish, Squalus suckleyi.[1] American Fisheries Society recommends the common name "Pacific Spiny Dogfish" for Squalus suckleyi  and "Spiny Dogfish" for Squalus acanthias. The maximum length of a Pacific dogfish can be 1.6 meters and they can live up to 66 years. Squalus suckleyi has a slower growth rate, larger maximum size, and later maturity compared to Squalus acanthias species. The slower growth rate and time of maturity could be related to the colder temperatures these sharks face.[2] Pacific spiny dogfish prefer to be in temperatures ranging from 7-15 degrees Celsius. Dogfish are found all over the world, but the Pacific spiny dogfish are found in the North Pacific Ocean. These areas range from the Korea's, Japan, and Russia.They are also found in the gulf of Alaska down to Baja, California.They are known to be meat eaters and eat other fish such as octopus, squid, and crustaceans. Squalus suckleyi have a slow reproduction rate compared to other sharks. Their gestation period is roughly about two years. This makes the Pacific dogfish more vulnerable to threats because they take longer to reproduce.[3]

Anatomy

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Size, Growth, and Age

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The Pacific Spiny Dogfish are small and skinny members of the Squalidae family. Throughout the entire Pacific Ocean, male and female dogfish measure up to be around 100 to 130 centimeters. Their length happens to be 10 centimeters more than the North Atlantic dogfish.[4] . Female Pacific dogfish reach a weight of 15 to 20 pounds by maturity, while the males tend to be much smaller in weight. The average maturation of the sharks normally take up to around 25 years and they can even live to the age of 100 years old.[5] This makes the Northeast Pacific spiny dogfish the longest living out of all sharks since the 1940s***** .

Appearance

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Its distinctive snout, large eyes, and flattened head are just a few of the physical characteristics that give the Pacific spiny dogfish its distinctive look.[6] The dogfish has a cylindrical shaped body. This type of shark also contains a unique body coloring. The top half of the shark has a gray color with scattered white spots while the bottom half has a white/light gray color. The scales of the dogfish is composed of the same material of shark teeth called dermal denticles, making the skin very hard and durable.[7] The skin of the sharks used to be used as sandpaper once dried to do woodwork or even be used as leather once the denticles are removed.[8] Lastly, the Pacific Spiny dogfish has a set of teeth specialized for grinding instead of tearing by the teeth being flat with sharp edges. If any of the teeth are worn down or broken, new teeth replace them from the two rows that are not being used to prey on other animals[9].

Spines and Fins

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Another specific characteristic of this type of shark is the structure of their fins. Relating to their name, the spiny dogfish have two spines that are in front of each dorsal fin, and does not contain an anal fin. The use of two spines on the outer body have been proven for the use of protection against enemies such as other sharks, humans, and even whales. The two fins are known for it's venomous nature. This is where the name "Spiny" comes into play due to the thorn like spines that are in front of each dorsal fin. The shark forms into a curled up ball and then attacks its predators[10]. Another use of the dorsal spines is being able to see age. The back set of fins closest to the tail is the best method of determining how mature the sharks are [11]. Not only does the spines provide useful attributes for this type of species, but the dorsal fins also give the shark advantages. The first pair of dorsal fins help the spiny dogfish maintain a stable body position while swimming. The second set of dorsal fins nearest to the tail aids in generating thrust. [12] The caudal fin is larger than normal, which helps the sharks maneuver through the water quickly and efficiently.[13]

Gills

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The Pacific spiny dogfish has a unique system of ventilation. This type of dogfish has five gills on each side of their heads, but do not have gill covers like bony fish. The shark is able to breath with these gills by swimming or staying in a current. The Pacific spiny dogfish also has a special feature called a spiracle. These are gills that are behind the eyes of the shark that give oxygen to the eyes and brain. It is also used to breathe while resting or eating.[14] The breathing of the dogfish happens as a two step process. First, the dogfish has water enter its mouth and exit through the parabranchial cavity, which then goes out through the five gill slits. The first three gill slits are primarily used for suction action. The four gill slit has the same purpose, but with a weaker activity. Finally, the fifth gill slit has water escaping while the Pacific spiny dogfish feeds on its prey.[15]

Habitat

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Location

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Dogfish in general live in three main areas of the ocean: the Pacific, Atlantic, and Indian ocean. This species can be found all around the world, but this specific type of spiny dogfish lives in the Pacific ocean. Spiny dogfish in the northern Pacific Ocean have recently been reevaluated and found to constitute a separate species, now known as the Pacific spiny dogfish.

Natural Habitat

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The Pacific dogfish's habitat consists of baysinshore and offshore waters. Female dogfish usually are usually seen in inshore waters while smalls pups are seen maneuvering in offshore waters.These animals are usually spotted at the bottom of the continental shelf or in other words the bottom of the sea. The Pacific dogfish prefers to live mainly in saltwater, but they can live in and tolerate brackish water (a mix of salt and fresh water).[16]

Threats

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Threats to Humans:

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The Pacific dogfish poses no immediate threat to humans. It is rare to hear about this type of shark attacking and injuring humans. The only significant way that the Pacific dogfish can cause harm to a human is if a person get near the poisonous spikes that are located at the dorsal fin.

Human Threats:

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The status of this species has been threatened over the past years by humans. This species is very vulnerable and has been suffering from overfishing which is having a significant effect on the Pacific dogfish population.[17] In the 1980s and the 1990s, the National Marine Fisheries Service influenced fisheries and fisherman to fish out the spiny dogfish because other types of valuable fish populations were declining due to overfishing.[18]Since all fisheries started to target the spiny dogfish population, their population started to rapidly decrease and became a threatened species. During the 1990s, there was a 75% reduction in female mature dogfish because dogfish fisheries started to increase.[19]Fisherman and fisheries usually target female dogfish because they are larger in size than males. Fisherman also target female dogfish because since they are larger in size, it is easier for fisheries to hold and cut them. From the start of 1998, people began to see that this population of spiny dogfish was declining, so the National Marine Fisheries Service decided to implement restrictions in the federal waters to help the population regrow.[20] The human race is threatening this species because dogfish is in high demand for food delicacies because the decline of other fish populations.[21]Scientists also ask for fisheries to fish out dogfish because they can secrete the molecule squalamine which is an aminosterol compound with potent broad spectrum antimicrobial activity discovered in the tissues. Scientists use this compound as an antibiotic for people with cancer.[22]

Threats from other species

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The main species of animals that threaten the Pacific dogfish population are sharkskiller Whalesseals, and larger bony fishes.[23] There would be a lot more predators of the Pacific dogfish if it wasn't for their size and aggressive nature, but mainly why these animals are not attacked is because poisonous spikes which are attached to the shark's dorsal fin which can be lethal to any predator who tries to attack and consume the Pacific dogfish.

Migration

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The Pacific dogfish usually undertake long migrations depending on the fluctuation of food that is available in the ocean and also depending on the temperature of the water.[24] Due to the changing temperature of the ocean, the dogfish usually migrate north in the spring and summer and they usually migrate south in the fall and winter.[25] This aquatic species is know to migrate seasonally off the shores of Canada. gran The species is known to travel a long way during migration. Some travel as long as 5,000 miles.[26] There have been some researchers who have suggested that the species do not mass migrate, only a small percentage of the spiny dogfish do based off their scientific research and evidence. This idea depends on where the dogfish is specifically located because the location, temperature, and food source can affect if there will or not be a small or big migration of dogfish.

Reproduction

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The Pacific dogfish have a longer reproduction rate compared to other sharks. The gestation period for spiny dogfish is normally 18 to 24 months.[27] Dogfish that live in cooler water may have an increased duration of pregnancy. Females are also known to migrate from deep to shallow water as the pregnancy continues.This migration pattern is known to influence embryonic growth. Baby dogfish found near Newfoundland had an average of 1.1 cm/month and 24 month pregnancy period, while a warmer area such as Massachusetts had an average of 1.3 cm/month and 20-22 month pregnancy period.[28] The sexual maturity of a dogfish is hard to determine because it varies anywhere from 10-30 years. Food supplies and water temperature also play a role in growth and development of the dogfish.The length of a newborn Pacific dogfish is around 22 to 23 centimeters. Females seem to be significantly larger than male dogfish. At sexual maturity the male dogfish is 60-70 cm while the female is about 70-100 cm. This length difference can be caused by the reproduction process of the female. Their bodies need to be bigger to carry and protect their eggs within their bodies. Pacific dogfish are ovoviviparous. This means that they produce eggs that hatch within the body. The size of the litter ranges from 1 to 20 newborns. Fertilization usually occurs from the beginning of October to the beginning of February.[2]

Diet

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The Pacific dogfish is an elasmobranchs or cartilaginous fish which includes sharks, skates and rays. Dogfish are carnivorous or meat eaters. Their teeth are sharp and are inclined laterally in order to cut through their prey. The Pacific dogfish usually eat on mollusks or crustaceans such as squid, krill, and shrimp. They will also eat other small sharks and fish. According to Jennifer Bigman, a marine scientist, concluded that there is no difference between what male dogfish eat versus what female dogfish eat.[29] Their prey are usually found on the sea floor, so the Pacific spiny dogfish has to scan the bottom in order to invest in their prey. Elasmobranchs consume very little carbohydrates and glucose. During times of starvation, they rely on ketone bodies to give them enough energy to survive. Cartilaginous fish are able to endure severe hypoglycemia due to their ketone oxidation. Although, Squalus suckleyi are able to eat more carbohydrates compared to other elasmobranchs. The rectal gland is activated when a dogfish consumes food. This gland helps the Pacific dogfish become glucose dependent. This means that they have the ability to break down small amount of glucose.[30]

From Wikipedia, the free encyclopedia

Pacific spiny dogfish
Conservation status
Least Concern (IUCN 3.1)
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Chondrichthyes
Order: Squaliformes
Family: Squalidae
Genus: Squalus
Species: S. suckleyi
Binomial name
Squalus suckleyiGirard, 1854
  1. Jump up^ Bigman, J.S., Ebert, D.A. & Goldman, K.J. 2016. Squalus suckleyi. The IUCN Red List of Threatened Species 2016: e.T195488A2382480. http://dx.doi.org/10.2305/IUCN.UK.2016-1.RLTS.T195488A2382480.en. Downloaded on 23 October 2017.
  2. Jump up^ Froese, Rainer and Pauly, Daniel, eds. (2016). "Squalus suckleyi" in FishBase. 10 2016 version.
  3. Jump up to:a b 
  4. Jump up^ Page, L.M., Espinosa-Perez, L.T. Findley, C.R. Gilbert, R.N. Lea, N.E. Mandrak, R.L. Mayden, and J.S. Nelson. 2013. Common and scientific names of the fishes from the United States, Canada, and Mexico, 7th edition. American Fishes Society, Special Publication 34, Bethesda Maryland.

The Pacific spiny dogfish stub only describes what kind of species the shark is. With the new table of contents that we have created, it will take the article more in depth with the life of the Pacific spiny dogfish.

1.) Word Count: 102 words

2.) There is no table of contents in the Pacific spiny dogfish Wikipedia article.

3.) There are only 4 sources.

Annotated Bibliography

Alejandro, G., Ana Carmen, D., A. Victoria De, A., Pablo, N., & Ramón, M. (1997). Anatomy and development of the sinoatrial valves in the dogfish (Scyliorhinus canicula). The Anatomical Record Part A: Discoveries In Molecular, Cellular, And Evolutionary Biology, 248(2), 224.

  • This source will help us understand the anatomy and development of the heart or sinoatrial valves of the dogfish.

Bigman, Jennifer (Summer 2013). "TROPHIC ECOLOGY OF NORTH PACIFIC SPINY DOGFISH (SQUALUS SUCKLEYI) OFF CENTRAL CALIFORNIA WATERS". Moss Landing Marine Laboratories California State University Monterey Bay.

  • This scholarly source will help writing about the diet and habitat of the Pacific dogfish.

Cooke, I. (1980). Functional aspects of the morphology and vascular anatomy of the gills of the endeavour dogfish, Centrophoms scalpratus (McCulloch) (Elasmobranchii:Squalidae). Zoomorphologie, 94(2), 167. doi:10.1007/BF01081932

  • This source explains the anatomy of the gills of the dogfish.

"Diets of Spotted Spiny Dogfish, Squalus suckleyi, in Marmot Bay, Gulf of Alaska, Between 2006 and 2014" (PDF). U.S. DEPARTMENT OF COMMERCE: 3. November 2016

  • This source explains the diets of the Pacific dogfish in Alaska.

Guffey, S. C., & Goss, G. G. (2014). Time course of the acute response of the north pacific spiny dogfish shark (squalus suckleyi) to low salinity. Comparative Biochemistry and Physiology - A Molecular and Integrative Physiology, 171, 9-15. doi:10.1016/j.cbpa.2014.02.004

  • This source will explain how salinity levels effect the Pacific dogfish.

Jones, T. S., & Ugland, K. I. (2001). Reproduction of female spiny dogfish, Squalus acanthias, in the Oslofjord. Fishery Bulletin, 99(4), 685-690.

  • This source is crucial for our reproduction portion in our article.

Ketchen, K. S. (1972). Size at maturity, fecundity, and embryonic growth of the spiny dogfish (squalus acanthias) in british columbia waters. Journal of the Fisheries Research Board of Canada, 29(12), 1717-1723.

  • This source talks about the size and maturity between a male and female dogfish.

Maia, A., & Wilga, C. A. (2016). Dorsal fin function in spiny dogfish during steady swimming. Journal Of Zoology298(2), 139-149. doi:10.1111/jzo.12300

  • This source will be used for the anatomy portion of our article.

McFarlane, G. A., & King, J. R. (2003). Migration patterns of spiny dogfish (Squalus acanthias) in the North Pacific Ocean. Fishery Bulletin101(2), 358-367.

  • This scholarly journal talks about migration patterns of the spiny dogfish in the North Pacific Ocean.

Natanson, L. l., McCandless, C. T., James, K., & Hoey, J. (2017). Gestation period and pupping seasonality of female spiny dogfish (Squalus acanthias) off southern New England. Fishery Bulletin115(4), 473-483.

  • This source will be helpful to explain the reproduction of the dogfish.

Penaluna, B. E., & Bodensteiner, L. R. (2015). North Pacific Spiny Dogfish ( Squalus suckleyi) Presence in Eelgrass Habitat in the Salish Sea, Washington. Northwestern Naturalist96(3), 222-226. doi:10.1898/1051-1733-96.3.222

  • This source is helpful in describing the habitats of Pacific dogfish.

R. W. Tanasichuk, , D. M. Ware, , W. Shaw, and , G. A. McFarlane. Canadian Journal of Fisheries and Aquatic Sciences, 1991, 48(11): 2118-2128,

  • This source talks about the variations of diets in a dogfish.

Reum, J. J., & Essington, T. (2013). Spatial and seasonal variation in δN and δC values in a mesopredator shark, Squalus suckleyi, revealed through multitissue analyses. Marine Biology, 160(2), 399-411.

  • This source will help us understand the locations of the dogfish.

Taylor, I. G., Gertseva, V., & Matson, S. E. (2013). Spine-based ageing methods in the spiny dogfish shark, Squalus suckleyi: How they measure up. Fisheries Research, 14783-92. doi:10.1016/j.fishres.2013.04.011

  • This scholarly journal compares the spine to aging a Pacific dogfish.

TRIBUZIO, C. A., MATTA, M. E., GBURSKI, C., ATKINS, N., & BUBLEY, W. (2016). Methods for the Preparation of Pacific Spiny Dogfish, Squalus suckleyi, Fin Spines and Vertebrae and an Overview of Age Determination. Marine Fisheries Review, 78(1/2), 1-13. doi:10.7755/MFR.78.1–2.1

  • This scholarly journal gives a brief overview of Squalus suckleyi.

Yıgın, C. C., & Ismen, A. (2016). Age and Growth of Spiny Dogfish Squalus acanthias (Squalidae: Chondrichthyes) in the North Aegean Sea. Pakistan Journal Of Zoology48(4), 1185-1191.

  • This scholarly journal discusses the age and growth of dogfish.

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Mount Everest Summary

Mount Everest is known to be the tallest mountain frame in the world. The official height of the Mount Everest is 8,848 m (29,029 ft). Although, some argue that the actually height is 8,844.43 m because the snow and ice is included within the actual height. The mountain range is an international border between China and Nepal. In Tibet, China the mountain is known as Chomolungma and Nepal it is known as Sagarmatha. The official English name "Everest" was named by the Royal Geographical Society. Also, Andrew Waugh, a British Surveyor General of India, suggested to name the mountain frame "Everest" which is named after his predecessor in the post, Sir George Everest. Although, the dangerous mountain frame has severe wind, weather, breathing conditions, and safety hazards this does not stop climbers from wanting to climb Mount Everest. The standard route of Everest is located in Nepal, but there is also another climbing route in Tibet, China. Since the first attempt of climbing Everest in 1921, on average 4.8 people have died each year trying to climb the mountain. The British were the first people to attempt climbing Mount Everest. During this time, Nepal would not allow foreigners in the country, so the British climbers tried climbing from the Tibet, China route making it 7,000 m. Later in the 1922 expedition, the British made it 8,320 m making it the first time a human being climbed over 8,000 m. There also has been many deaths and mysteries concerning Mount Everest. George Mallory and Andrew Irvine attempted to climb Mount Everest on June 8, 1924, disappeared in the clouds, and never returned. Mallory's body was found in 1999 at 8,155 m on the north face. Despite the fact there have been many failures trying to climb Everest, the first recorded success of climbing Mount Everest peak was done by a Chinese climbing team: Wang Fuzhou, Gonpo, and Qu Yinhua.

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  4. ^ "Web Login Service". search.proquest.com. ProQuest 17936290.
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  29. ^ Bigman, Jennifer (Summer 2013). "TROPHIC ECOLOGY OF NORTH PACIFIC SPINY DOGFISH (SQUALUS SUCKLEYI) OFF CENTRAL CALIFORNIA WATERS". Moss Landing Marine Laboratories California State University Monterey Bay.
  30. ^ "Diets of Spotted Spiny Dogfish, Squalus suckleyi, in Marmot Bay, Gulf of Alaska, Between 2006 and 2014" (PDF). U.S. Department of Commerce: 3. November 2016.