Marine Animals: Emperor Penguin

There are 17 species of penguin known to exist on planet Earth. Aptenodytes forsteri, the Emperor Penguin, is the largest, standing around 4 feet tall and weighing 51 pounds. Like all other penguins, emperor penguins are flightless, with specially-adapted flippers for swimming. The bodies of emperor penguins are counter-shaded, with black backs and white bellies, with characteristic bright orange necks. This pattern of colors helps to hide emperor penguins from predators while they are hunting or swimming.

The life cycle of Emperor Penguins

Emperor penguins are the only penguins that breed on the main Antarctic land mass in winter. Colonies of up to 60,000 breeding pairs can be found scattered across the Antarctic continent. The breeding cycle begins in the austral autumn, when sea ice is thick enough to support large colonies of penguins. Emperor penguins engage in a variety of behaviors when attracting a mate, including strutting around on the ice, singing, and head bowing or swinging. Once an egg has been produced, the male penguin will balance it on top of his feet and incubate the egg under a fold of skin, keeping it warm at a temperature of about 38 C, despite temperatures dropping to a teeth-chattering -35 C. Females spend the period between late May and July hunting while males guard the eggs. When the females return, mates locate each other by calling.

Rising global temperatures may threaten emperor penguin populations in the future. Warmer oceans will decrease the extent of sea ice in winter, which is vitally important for krill, an important prey species of emperor penguins. Coupled with overfishing of krill populations by humans, emperor penguins face considerable threats to their survival in the future.

The range of Emperor Penguins is restricted to Antarctica. Image from: https://upload.wikimedia.org/wikipedia/commons/c/c1/Manchot_empereur_carte_reparition.png

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: James Chapman and Christopher Crookston

Editor: James M. Fiorendino

Contributing Professor: Dr. Lisa Campbell

Cover Image: Vlad Silver, https://www.wildimages-phototours.com/photography-tours/emperor-penguins-antarctica/

Marine Animals: False Killer Whales

The false killer Pseudorca crassidens, is neither a killer whale nor a whale at all, but a large species of dolphin! When it was discovered, the skull of this cetacean was determined to be very similar to that of the killer whale, Orcinus orca, which lead to its description as “false killer whale”.

False Killer Whales grow to between 15 and 17 feet long, with females growing on average 1 to 3 feet shorter than males. Their characteristic features include dark grey or black skin, with a light patch of skin on the underside of the neck below the eye. With streamlined bodies, these dolphins are powerful swimmers.

Photo: Peter Jucker, from: https://uk.whales.org/sites/default/files/styles/flexslider_full/public/species/pseudorca_crassidens-peter_jucker_swiss_whale_society.jpg?itok=PIov2cZk

False killer whales inhabit tropical and semitropical regions around the world, usually in open ocean waters but venturing into coastal waters occasionally. Populations have been found in Hawaiian waters and the Gulf of Mexico. The Hawaiian population of False Killer Whales is classified as endangered; numbers of Hawaiian False Killer Whales have declined at a rate of 9% per year since the early 2000s. A survey conducted in 2010 estimated the size of this population of False Killer Whales to be around 1550 individuals. Unfortunately, the Hawaiian False Killer Whales are the only well studied population in United States waters.

Distribution of False Killer Whales in the world oceans. From: https://www.fisheries.noaa.gov/species/false-killer-whale

Fisheries are the primary threat to False Killer Whales. False Killer Whales try to eat bait or fish caught on commercial fishing lines, becoming hooked or entangled leading to serious injury or death. Commercial fisheries target many of the same species False Killer Whales feed on, including tuna, billfish, wahoo, and mahi mahi. Other threats include exposure to toxic chemicals from pollution, resulting in disease or damage to the reproductive systems of False Killer Whales.

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: Aleck Hernandez and Cydney Sutherland

Editor: James M. Fiorendino

Contributing Professor: Dr. Lisa Campbell

Featured Image: NOAA

Marine Animals: Dall’s Porpoise

Top Image from: NOAA

The Dall’s Porpoise Phocoenoides dalli, is one of the fastest animals in the ocean, and the fastest cetacean. These porpoises can swim as fast as 35 miles per hour. The great speed of the Dall’s porpoise allows it to effectively elude predators and hunt prey. The diet of the Dall’s porpoises consists primarily of small fish and cephalopods. They are known to dive to depths of over 300 feet. Dall’s porpoises are commonly hunted by killer whales and great white sharks.

Porpoises are closely related to dolphins, differentiated from dolphins by their spade-shaped teeth, triangular dorsal fins, and the shape of their heads, which are compared in contrast to a dolphin’s elongated jaws. The Dall’s porpoise is identified by its thick body, small head, and coloration similar to that of killer whales. Their dorsal side and most of their body are dark grey or black, with white patches on their sides and belly. The tip of their dorsal fins and flukes may also be white or grey. Dall’s porpoises, and porpoises in general, are smaller than dolphins and whales. They grow to lengths of 7.5 feet and weigh between 290 and 490 pounds. Males are general larger than females.

The white-tipped dorsal fin of a Dall’s Porpoise. Image from Ocean Ecoventures https://oceanecoventures.com/wildlife-galleries/dalls-porpoise/

Unfortunately, the Dall’s porpoise’s great speed cannot help it outrun other threats. These cetaceans are commonly caught in fishing nets, becoming completely stuck or dragging the net along with them, hindering their swimming speed and making them unable to hunt or avoid predators. Dall’s porpoises are also hunted for food by Japan, the only country to still do so. Japan harvests 18,000 porpoises annually. Pollution and noise from human activities also have a negative impact on Dall’s porpoises.

Dall’s Porpoises captured by Japanese fishing vesesls. Image from: https://www.ecowatch.com/japan-animals-hunting-2617103070.html

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: Caroline Burks and Kayla Inman

Editor: James M. Fiorendino

Contributing Professor: Dr. Lisa Campbell

 

Paleoceanography 5: Chasing a Ghost

Is it possible to catch a ghost? Major ocean features like western boundary currents are fairly stable today, but millions of years ago they may have been quite different. Unfortunately, unlike living things which may leave fossils or biomarkers for scientists to find, currents have no physical remains. Scientists at Texas A&M University are working to capture a long-dead specter as they attempt to uncover the location of the Kuroshio Current millions of years ago.

Surface waters flow in a circular pattern in major ocean basins, clockwise in the Northern Hemisphere and counter clockwise in the Southern Hemisphere. Western Boundary Currents like the Kuroshio Current occur at the western edge of ocean basins. They are fast and narrow, transporting massive amounts of warm water from the equator to the poles. As the Kuroshio current flows north, it turns to the right, extending into the middle of the Pacific Ocean basin. The greatest temperature gradient with latitude in the western Pacific Ocean occurs between 38- and 40-degrees north. This gradient is associated with the Kuroshio Extension, where the current turns into the open ocean.

This diagram shows the general circulation patterns of the North and South Pacific Ocean. Boundary currents are circled; western boundary currents are found on the western edge of ocean basins, in this case off the coast of New Zealand and Japan. Image from: https://oceanservice.noaa.gov/education/tutorial_currents/04currents3.html

The Kuroshio Extension shifts north or south seasonally and over long time periods. Identifying where both the Kuorshio Current and Extension were millions of years ago is important for reconstructing past heat transport and carbon cycles in the ocean. As the Kuroshio Current flows northward and releases heat, the water cools and the solubility of CO2 increases. Therefore, regions of large temperature gradients associated with western boundary currents are where the greatest amount of CO2 enters the oceans.

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.

Featured image from: Mikkel Juul Jensen/SPL/Cosmos (left) and Aphelleon/Shutterstock (right)

Script Author: James M. Fiorendino

Contributing Professor: Dr. Yige Zhang