Steller sea lions (Eumetiopias jubatus) are the only member of Eumetiopias and are one of the biggest of the eared seals. Steller sea lions feed mainly on fish, and sometimes even various types of shellfish. Many Steller sea lions can be found along the coast of Western Alaska. Generally, Western Alaska has relatively warm summers, cold winters, and mild temperatures during the spring and fall, with the highest amounts of rainfall during the summertime. Steller sea lions have recently come under the scope of many researchers because of their sudden and significant decline of population in recent times. In some places such as the Aleutian Islands, which is an island chain found in the Western part of Alaska, the population of Steller sea lions …show more content…
One hypothesis proposes that the reason Steller sea lions have been declining is because of low prey abundance. Animals should use their energy efficiently when they forage to maximize the net amount of energy gained in relation to the amount time and energy that is spent, but it is believed that the reason Steller sea lions are disappearing in such big numbers is because when prey abundance is lower, that Stellar sea lions are less efficient predators (Charnov, 1976). In a recent study conducted on the effect of prey abundance on foraging efficiency, it was found that the less prey that Stellar sea lions had available, the less efficient they were in foraging (Goundie et al., 2015). In the experiment, the researchers took 4 adult Stellar sea lions and had them dive up and down a tube while recording their oxygen consumption, and dive duration. The sea lions dove between the surface of the water and depths of 10 m, and 40 m, and the reason for this was to simulate diving depths of Steller sea lions in the wild (Merrick and Loughlin, 1997). While the sea lions were diving, researchers fed them pieces of fish through two different tubes that were placed away from each other in order to simulate real foraging movements and prey densities. The researchers fed the seals 12 pieces of fish in the …show more content…
An experiment documenting the effect of feeding low-quality prey like pollock to Stellar sea lions was conducted (Jeanniard du Dot et al., 2008). In the experiment there were two groups of Stellar sea lions, group H and group P. Group H was fed less herring and group P was fed pollock in equal amounts regarding caloric content. After feeding each group the restricted diets, the researchers recorded the foraging behaviors of the sea lions over the summer and the winter. All of the sea lions increased their foraging behaviors during the summer, when prey is abundant, but only group H conserved conserved energy during the winter when prey is less abundant. Group P did not reduce energy consumption in order to use energy more efficiently when it turned winter because they had less energy to use during the winter due to the low-quality diet, and that low-quality diets hurt the sea lions during times of nutritional stress (Jeanniard du Dot et al., 2008). A journal article also documented that young Stellar sea lions were more impacted by a low quality diet (Rosen, 2009). It was seen that young sea lions were more impacted by a low quality diet because of their higher energy requirements, and also their digestive capacity, which means they can't even consume a higher quantity of lower quality fish to compensate. Both of these experiments explain how low quality prey can
A Review of “The Devil and Deep Blue Sea” by Linda Pannozzo Introduction In her book The Devil and the Deep Blue Sea: An Investigation into the Scapegoating of Canada’s Grey Seal, Linda Pannozzo accomplishes few important things: she makes a compelling argument for the senseless killing of grey seal; she provides an analytic framework for the reasons of the decline of cod fish; and she provides a wealth of information on the politic behind scapegoating of Canada’s grey seal. Pannozzo presents The Devil and Deep Blue Sea in a clear and unbiased matter, but its presentation is by no mean elementary. Pannozzo’s book is meticulously researched, thus providing us with both quantitative and statistical account surrounding seal ways of life, their diet, history and other necessary aspects of marine life ecosystem. Book Summary
California Sea Lions are found off the west coast primarily in the Channel Islands off the California coast. Males can reach up to 850 pounds,
In 2008 the U.S Army Corps of Engineers observed 17 Steller Sea Lions eat 606 White Sturgeon below the Bonneville Dam. Which counted for 98 percent of the predation documented by sea Lions on Sturgeon that year. While California Sea Lions counted for 96 percent of the predation on Salmon and Steelhead that Year. As the facts shows the Steller Sea Lion is mainly the one preying on the White Sturgeon and the California Sea Lion is mainly preying on the
Bradshaw, C.J.A., Hindell, M.A, Best, N.J., Phillips, K.L., Wilson, G. and Nichols, PD. (2003). You are what you eat: describing the foraging ecology of southern elephant seals (Mirounga leonina) using blubber fatty acids. Proc. Roy. Soc. Lond. B. Biol. Sci. DOI 10.1098/rspb.2003.2371.
Bottlenose Dolphins are a very interesting animal. They have a fusiform (Spindle shaped) body that allows them to move quickly in the water. Because of the Dolphins’ shape they have bilateral symmetry. They also have a dorsal fin, flippers, and a fluke. However, Bottlenose Dolphins do not have ears on the outside of their bodies, hair, or hind limbs. The color of this type of dolphin is usually a light grey color to a black. Their stomach is white and sometimes has a pink hue. One physical adaptation these dolphins have is a telescoped skull. The skull is like this because it allows them to breathe more easily while swimming. Bottlenose Dolphins also have blubber that they use as insulation and vascular shunts that allow them to have cooling for certain types of organs and tissues in their bodies. Finally, Bottlenose Dolphins have sharp teeth that let them grasp onto their prey, so their tongue can push the prey down the dolphin’s throat. Bottlenose Dolphins have a range mass of 260 to 500kg which is 572.69 to 1101.32 in pounds. The average mass of the Bottlenose Dolphin is 400kg. Their average mass in pounds is 881.06.
Steller sea lions have few predators. Their main predators are killer whales, Great white sharks, Pacific sleeper sharks, and humans. Steller sea lions defend themselves by outswimming their predators. They can also sense when predators are nearby and their biggest defense is to get onto land. Their preys are the wide range of animals that they feed on. They track their behavior by diving deep as the prey moves deeper, and they gather in groups in locations that have seasonal runs of fish.
Most people would not appreciate a stranger walking into their home unannounced, taking their food, and making themselves at home. That is exactly what lionfish are doing along the Florida coastline. Lionfish are an invasive species that need to be contained. The reefs that they consistently invade off of the coast of the Florida are not the lionfish's natural habitat. This invasive species takes shelter and resources out of the reef that other species need to survive, and they destroy the environment around them. Humans have complicated the balance of the ecosystem by introducing lionfish, and now they need to help rectify the situation.
The seal lion population has decreased by eighty-percent. The weird thing is that there is no bodies to prove that the seal lions are gone. Some of the causes of the decrease could be fisherman, pollution, and killer whales. The sea lions could also be starving to death. The fisherman are taking all of their sources of food. But, in Alaska the sea lions are thriving and the whales are not. Thirty years ago ninety percent of the whale population was gone in Alaska. This resulted in an abundance of more krill and plankton, which lead to more pollock and herring. The sea lions ate the herring the most as it was healthier and kept them full. But, when the herring population decreased the sea lions had to eat pollock. Pollock is the “junk food
In the film we watched how scientists are trying to explain the mystery involves in the declining number of ocean lion. The scientists in Alaska are making some investigations; they already have set down some hypothesis for the disappearances of ocean lion. Their hypothesis state that the cause of the declining in number of the ocean lion can be caused by their food, the oil spill, or diseases. In this experiment, they are searching to identify the factors that are causing the premature dead of these young animals. They said because there is not body to study is hard to know what is happening to the ocean lions. For this reason, the scientists are taking some ocean lions from their natural habitat and are testing their DNA to identify any
The sea lions currently populating the docks in Astoria Oregon may be causing serious depletion of fish as well as causing problems for the infrastructure of the docks they reside on. They are native to the California coastline but have made their way to the docks in Astoria which lies on the Columbia River. The reason this can be such a problem is because when you introduce an animal population that does not have any predators in their new habitat it can lead to overpopulation which leads to underpopulation of what they consume. In this case, the california sea lions are overpopulated and eating too many of the fish in that area of the Columbia River. The overpopulation of sea
Orcinus Orca, or more commonly known as the Killer Whale, is found in waters worldwide ranging from the Antarctic to tropical regions. Killer Whales are considered to be apex predators of the ocean and have no natural predators. Killer Whales have been observed consuming a large diversity of different marine animals such as fish and squid (Coscarella et al., 2015) and also prey on Subantarctic Fur Seals, which is what they are more commonly known to feed on (Pistorius et al., 2012). Pitman and Durban (2010) also made observations of Killer Whales hunting penguins in the Antarctic. Trying to understand how this top predator regulates the food web involves knowing the relationships among species and also their population size and diet (Coscarella et al., 2015). Killer Whales use different hunting techniques while trying to catch their food and are also very social creatures and tend to hunt in pods. Some Killer Whales have been observed simply chasing their prey until they tire or using a more advanced hunting tactic such as diving to deep depths to get their food, also another unusual activity observed are Killer Whales playing with their food.
levels of chemicals which might have caused the decline of sea Otters. However, the lecture argues that Predation theory is
Our specialty is custom printed fabric including shower curtains, handbags, wall dividers, pillows, liturgical banners, theater backdrops and the alumiframe for both residential and commercial. The alumiframe is unique to Giant Printing; it’s a custom printed fabric frame system that will bring any residential or commercial interior to life.
Since 2001, Portugal has prioritized harm reduction in drug abuse and have treated addiction as a health issues instead of a crime issue. Many believe that this policy has reduced drug addiction, but others feel that it has encouraged the use of illegal drugs. I believe that Portugal is taking the wrong stance against drugs and should be viewing them in a criminal manner. This policy can be supported in historical context via the burning of opium by the Chinese government and by the use of methamphetamine by German soldiers in World War II.
Do you know what the biggest animal ever to live on Earth is? You would be wrong if you speculated a dinosaur, elephant, or giraffe. You may be surprised to find out that the biggest animal ever to live on Earth is the Blue Whale and it is still alive today. The Blue Whale weighs as much as 33 elephants and consumes about 4 tons of food a day. I bet if you knew of an animal that was as long as 3 school buses you would want to keep this animal in the world forever. Although, the Blue Whale may not stay for long, many things affect the blue whale’s inhabitance, mainly the acts of humans have caused the Blue Whale’s to become endangered. Though, if you know the information about them you can help.