Year 2 Antarctica -Life among the frozen

Life among the frozen

The term “biological hotspot” is not one you expect to connect with Antarctica, the most remote and inhospitable continent on Earth. Antarctica remains the only continent to be surrounded by a single current, the Antarctic circumpolar current, which flows eastward and connects water from all of the other major oceans. Scientists have long studied this frigid landscape and marveled at the whales, seals and penguins that call this land and the surrounding ocean their home. Just below the surface of the ice, however, a hidden ecosystem teems with life. Microscopic, photosynthesizing “plants” called phytoplankton fill these nearshore waters, making the water below the ice look green or brown. These organisms form the base of the Antarctic food chain, and serve as food for the larger organisms up through food chain. How do these phytoplankton live below the ice where water temperature is below freezing? Sufficient light is able to pass through the ice to support photosynthesis, and the cycle of ice formation and melt produces natural turbulence that carries the essential nutrients that these phytoplankton need up to the surface. This upwelling phenomenon occurs most often in the shallow, nearshore waters, such as along the Western Antarctic Peninsula (WAP), or the “tail” of the Antarctic continent. The strong biological activity in the nearshore regions is in stark contrast to the majority of the Southern Ocean, which is largely devoid of phytoplankton. We’ll talk about why that is on the next On the Ocean! This has been On the Ocean, a program made possible by the Department of Oceanography and a production of KAMU-FM on the campus of Texas A&M University in College Station. For more information and links, please go to ocean.tamu.edu and click “On the Ocean”.

Script Author: Laramie Jensen

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Krill larvae under the sea ice in Antarctica

Fisheries -Atlantic Salmon

I’m McKensie Daugherty, your host for On the Ocean. Have you ever eaten salmon because you have heard of it’s “many” health benefits… Like shinier hair, speedier metabolisms, improved brain function, or maybe because it’s the perfect source of lean protein? Well, at a whopping 28-30 inches long and 8-12 pounds, these gigantic and adaptable fish, the atlantic salmon, have a wide range of amazing aspects. These fish are what you would call anadromous – where they spend half their life in freshwater, and the other half in the ocean, only to return to freshwater, fighting through deadly currents, to spawn and die. The atlantic salmon, scientific name salmo salar, also called kelts, black salmon, or the red run salmon, are the only type of salmon that are native to the atlantic ocean, and can be found on the north-east coast of the United States. However, in the wild, these beautiful black-spotted silver-blue salmon are actually endangered, with the population being at a record low. The salmon that you get from your local grocery store are raised on farms because of this. Commercial fishing for the atlantic salmon is illegal due to the overfishing and habitat destruction from 1979 to 1990 in which total catches fell from 4 million to 700,000 per year. Don’t worry too much though because the fishing and farming of these beautiful animals are managed by an abundance of regulations such as the Endangered Species Act, the National Environmental Policy Act and the Clean Water Act. Current worldwide aquaculture production of the atlantic salmon exceeds 1,000,000 tonnes per year, account for over 50% of the total global salmon market, and are mostly farmed in Japan, the european union, and the united states. It is legal to catch retired salmon recreationally in some states through angling but because these fish near extinction in the wild, we must all work together to keep this unique species safe. This has been On the Ocean, a program made possible by the Department of Oceanography and a production of KAMU-FM on the campus of Texas A&M University in College Station. For more information and links, please go to ocean.tamu.edu and click “On the Ocean”.

Script Authors: Kalan Barnes & Patrick Chandler

salmondiagram

Figure 1: The physical characteristics for identification of the atlantic salmon.

http://www.aquaticnuisance.org/fact-sheets/atlantic-

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Figure 2: From the 1970s to the 1990s and on, the wild population of atlantic salmon decreased drastically and has been struggling to grow.

http://www.asf.ca/greenland-take-was-63-of-harvest-for-salmon-returning-2014.html

Species in the Spotlight: Atlantic Salmon

http://www.nmfs.noaa.gov/stories/2015/12/spotlight_atlantic_salmon.html

North Atlantic Salmon Conservation Organization

http://www.nasco.int/atlanticsalmon.html

Salmo Salar: The Atlantic Salmon

http://www.fao.org/fishery/culturedspecies/Salmo_salar/en

Fisheries -Swordfish

Fisheries -North Atlantic Swordfish

The North Atlantic swordfish is appropriately named for its long, sword-like bill and they are one of the fastest predators in the ocean due to its streamlined body.  Contrary to popular belief, the “sword” is not used to spear, but instead is used to slash at its prey to injure the animal, to make for an easier catch. On average, swordfish are about 10 feet in length, but can reach up to 15 feet and 1400 pounds!  Swordfish are found widely in tropical and temperate parts of the Atlantic, Pacific, and Indian Oceans. Swordfish are caught both commercially for their tasty meat and recreationally, as they are a challenge to catch because of their speed and agility in the water. Commercially, fishermen usually use pelagic longline gear to harvest swordfish. Recreationally, use rod-and-reel, harpoon, and buoy gear. These types of gear have no impact on the habitat because they don’t touch the ocean floor. NOAA Fisheries and the Atlantic Highly Migratory Species Management Division manage swordfish in the North Atlantic and the Gulf of Mexico. Since the Atlantic Swordfish is a highly migratory species, they have more complicated management plans that require international cooperation. Fortunately, the management has proven to be highly effective and swordfish have not been overfished, and are not endangered.  This has been On the Ocean, a program made possible by the Department of Oceanography and a production of KAMU-FM on the campus of Texas A&M University in College Station. For more information and links, please go to ocean.tamu.edu and click On the Ocean.

Script Authors: Lindsay Sauer and Greg Matunas

Additional Information

swordfish

http://marinesciencetoday.com/wp-content/uploads/2012/12/Swordfish-and-tuna-account-for-more-than-half-of-the-mercury-intake-from-seafood-in-the-US.-Photo-credit-NOAANMFS..jpg

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Fisheries -Skipjack Tuna

I’m McKensie Daugherty, your host for On the Ocean.  Skipjack tuna are the smallest and most abundant of the major commercial tuna species.  Larger tunas such as yellowfin, Bluefin, and albacore, are being fished at or near maximum sustainable levels, and there has been a rapid acceleration in efforts to develop skipjack tuna fisheries.  They range in size from 40cm up to 110cm and can weigh as much as 76 lbs.  Skipjack tuna are found mainly in the tropical areas of the Atlantic, Indian and Pacific Oceans, with the greatest abundance seen near the equator.  They inhabit the surface waters in large shoals of up to 50,000 fish.  Skipjack are commercially important as the main species of canned tuna.  In the Gulf of Mexico, vessels may only fish using a general rod and reel, longline, purse seine or harpoon method.  Since juvenile yellowfin and bigeye tuna often school with adult skipjack, they are sometimes inadvertently caught by purse seine vessels that target the skipjack.  Rod and reel or fishery options are currently being promoted as ecologically preferable.  As stated by NOAA Fisheries, there are currently no catch quotas in place for the skipjack tuna.  In 2013, Skipjack tuna accounted for 68% of the total tuna catch of 2.6 million tons. This has been On the Ocean, a program made possible by the Department of Oceanography and a production of KAMU-FM on the campus of Texas A&M University in College Station. For more information and links, please go to ocean.tamu.edu and click On the Ocean.

Author: Anita Boggs

tuna

Photo of a skipjack tuna shoal.

Photo credit: http://www.worldwildlife.org/species/skipjack-tuna

A net bulging with tuna and bycatch on the Ecuadorean purse seiner 'Ocean Lady', which was spotted by Greenpeace in the vicinity of the northern Galapagos Islands while using fishing aggregating devices (FADs). Around 10% of the catch generated by purse seine FAD fisheries is unwanted bycatch and includes endangered species of sharks and turtles. The catch of large amounts of juvenile bigeye and yellowfin tunas in these fisheries is now threatening the survival of these commercially valuable species. Greenpeace is calling for a total ban on the use of fish aggregation devices in purse seining and the establishment of a global network of marine reserves LAT 04:09 NORTH / LONG 091:31 WEST

A net bulging with tuna and bycatch on the Ecuadorean purse seiner ‘Ocean Lady’, which was spotted by Greenpeace in the vicinity of the northern Galapagos Islands while using fishing aggregating devices (FADs). Around 10% of the catch generated by purse seine FAD fisheries is unwanted bycatch and includes endangered species of sharks and turtles. The catch of large amounts of juvenile bigeye and yellowfin tunas in these fisheries is now threatening the survival of these commercially valuable species. Greenpeace is calling for a total ban on the use of fish aggregation devices in purse seining and the establishment of a global network of marine reserves
LAT 04:09 NORTH / LONG 091:31 WEST

Photo credit: http://www.greenpeace.org/usa/eat-tuna-know-fish/