In normal conditions, cold water, rich in nutrients, flows in a northerly direction along the west coast of South America. This is accompanied by an upwelling of nutrients, caused by winds blowing form the south. This results in the water having a high productivity, with very large numbers of anchovies and sardines feeding in the plankton-rich water. This high productivity supports a substantial fisheries industry and many species of sea…
Wolffish are known to migrate small distances base on a study conducted by Templeman, (1984). The study suggested that they may follow food short distances in order to protect the bait from other fish. Their primary food Ctenophora or Comb Jellies (Concepción González, Xabier Paz, Esther Román and M. Alvárez, 2006) (Figure: 2) are were found most often in the stomachs of Northern Wolffish. Northern Wolffish are distributed over a wide range of depths, from 38 to 1504 m the maximum depth surveyed by Concepción González, Xabier Paz, Esther Román and M. Alvárez (2006). The densest concentrations of fish occurred offshore between 500m and at temperatures ranging from 2 to 5° C. Temperature is an important feature of wolffish habitat. All the species of…
Forsythe attempts to magnify the size of the issue by suggesting that the only solution to solving the number of attacks is to kill a number of sharks reducing the species population. He uses statistics of “seven attacks in the last 4 years” to encourage the reader’s support. This positions the reader to view the writer’s argument as more convincing because it appears to be objective and reliable.…
Since the 1970’s when the movie Jaws first showed up on big screens around the country, people have been afraid of beaches, in fear of shark attacks. Not only have they been apprehensive about swimming in the ocean, but some have such malicious feelings towards sharks (especially Atlantic White Sharks due to their role in the movie) that they have taken to hunting and killing this already dwindling species. (Earth Island Institute) It is no secret that pollution and overfishing, as well as numerous other factors have caused the biodiversity of marine life to drastically decrease. It is also known that the ocean ecosystem relies much on all members of the food chain- particularly top predators like sharks. Larger sharks,…
maenas is cannibalistic, especially in postlarval and juvenile stages (Moksnes et al., 1998). This cannibalism tends to be density dependent and self-regulates populations of C. 5 maenas (Moksnes, 2004). Mortality by means of predation by H. sanguineas serves to further thin populations. C. 5 maenas is also very efficient in selecting habitats with low risk of predation (Moksnes, 2002). H. sanguineus populations are at higher densities in rocky intertidal areas, the same refuge habitat preferred by juvenile C. maenas. In response, C. 5 maenas has shifted habitat usage to areas with reduced refuge (Jensen et al. 2002). 5 This habitat shift also creates a shift in diet in adults from primarily consuming mussels to primarily consuming red algae (Griffen et al., 2008). Reduced refuge creates risk of predation by seabirds, fish, and other predators. Dietary shifts of C. 5 maenas in the presence of H. sanguineus could reduce C. maenas populations in two ways. First, this shift in diet decreases nitrogen consumption which slows growth rates of C. 5 maenas, potentially extending the time susceptible to size dependent predation (Griffen, 2008). In the presence of H. sanguineus, C. maenas typically forages for red algae (Chondrus crispus) containing 0.4%-1.4% nitrogen with higher values in winter and lower in summer (Chopin and Floch, 1992). Otherwise, C. maenas would prey on mussels (Mytilus edulis) containing 7.7%-9.6% nitrogen with higher values in spring and lower in late…
Zebra Mussels have been becoming more and more of a topic since they first came into the US by a boat to the Great Lakes. This shows how they have come here and the effect of the being here and possible ways to control the mussels.…
Nale, M. (2004, September 8). The Crayfish Corner - Information. mackers.com. Retrieved November 27, 2011, from http://mackers.com/crayfish/info.htm…
Devil fish, also known as suckermouths, have invaded the waters of the Mexican state of Tabasco. This armored catfish is cherished among aquarium owners because they eat the algea that grow in the tanks, but out in the wild, this behavior harms underwater plant life and erodes shorelines. Along with this, the introduction of these fish has resulted in a decrease in numbers of Robalo, or snook, in these impacted waters. It’s unclear as to how these devil fish became a problem, but it’s thought to be a combination of aquaculture facilities accidentally releasing them, and the “Nemo effect, where the fish grew too large for their tanks and were then released into the wild by. After the initial release, the populations exploded due to their abilities to mature quickly, lay 500 eggs at a time, and their long life spans (7 to 15 years). In an effort to try and reduce the number of devil fish, Acari was born, a company that has attempted to catch and sell these invaders as food. Although this fish isn’t poisonous, marketing it for human consumption has proven to be difficult. In addition to selling fillets to restaurants, Acari hopes to help migrants and refugees through the donation of fish.…
A steep decline of predatory fish and a new oceanography that allows larvae to flow into their “nursery”.…
Many people aren’t sacred to enter the territory of sharks and their environment. A number of Australian’s oppose the culling of sharks and do not fear of getting back into the ocean. Miranda Devine published an opinion piece with the headline “A tasty dish for a very big fish… and it’s all our fault” in The Daily Telegraph newsletter on February 12th, 2014 with the contention that it is our fault that we have become part of shark’s food chain. This is directed to the people that do not support the culling with a very direct tone.…
Particularly, some top predators, such as groupers and Bluefin tuna can lead to changing marine communities with reduction of the great big, long lived, and high value carnivorous. Instead, the smaller, short lived, and lower value such as sardines and anchovies increase (Lubchenco). Although we do not know exactly how much Bluefin tuna are left in the ocean, we estimate the amount we caught. Some experts said, "The Atlantic Bluefin population has declined up to 85 percent from its original numbers" (Richardon). Some fishermen find and catch Bluefin because of their profits even thought some Bluefin do not become the target of catching to fatten. Bluefin are 11 ages to reproduce, and scientists believe in that (Richardon). About the environment and the other organisms, we should get a good understanding how Bluefin tuna affects. It is one of parts of the marine food web, so it is at the top and feeds on smaller fish to balance the organisms. The process of photosynthesis between plants and sun is created the energy for humans. The environment becomes too worst if ocean has no Bluefin tuna ("Overfishing: A Global Concern"). NOAA states that the mission of NOAA is to predict the changes in the Earth's environment, from the depths of the ocean to the surface of sun, and it understands how to conserve and manage the marine resources. Bluefin tuna currently do not warrant species protection under the Endanger Species Act, so NOAA needs human to realize how Bluefin tuna is important fish in the ecosystem to save them for the next generation ("Endangered Species Listing for Atlantic Bluefin Tuna not Warranted"). Because of some activities causes, Bluefin's birth is interrupted. Definitely, Bluefin tuna could disappear if we fished in the same way…
Large sharks such as tiger and bull sharks, both of which do enter bays, estuaries and river mouths, may pose a threat to Florida manatees in those waters. Other potential predators include American alligators and crocodiles, the latter wide-ranging along the South Florida coast. Orcas, which have been implicated in attacks on dugongs in the Indian Ocean, aren’t particularly common in manatee range. Calves are likely more vulnerable than adults to such…
Did you know that almost eighty percent of the fish living on a reef could be killed by a single fish that is only about the size of a human hand? This fish happens to be called the lionfish and is mostly known for its beautiful features and deadly poison. Lionfish are indigenous to the Pacific Ocean; however, they have recently invaded the Atlantic Ocean and are growing in population at an uncontrollable rate. Marine biologists and even everyday snorkelers fear the dangers of these fish and have even started taking the matters of getting rid of them into their own hands. On the other hand doctors, chefs, and even snorkelers consider lionfish to be very useful and entertaining. According to marine biologists, the…
Great white sharks are known as the most dangerous of the shark species because of their sheer size and their quick mind that make them the ultimate predator. A comparison can be seen in Figure 1, where the great white shark is seen next to a human, this image is showing the sizing difference between the two species. The shark is so captivating that there is an entire week each year dedicated to these creatures to learn more about them and the world they live, in an area that is vastly undiscovered. There is enough evidence through fossils that can date the shark back four-hundred million years ago, which was a time before dinosaurs were roaming the Earth (“Shark Basics”).…
Before the 1990s, few people had heard of the Patagonian toothfish. But in the 1990s, it…