Climate Spotlight: Bottlenose Dolphin

Featured image from: https://www.inaturalist.org/photos/9420229?size=original, Photo Credit: Jeff K, from https://www.inaturalist.org/photos/9420229

Everyone has heard about how smart dolphins are. A dolphin’s brain is astonishingly complex, almost comparable to that of humans, and relative to their body size, quite large. Through magnetic resonance imaging, their brains have been found to be 4 – 5 times bigger than those of other similarly sized animals.

When you think of dolphins, the first image that comes to mind is probably the bottlenose dolphin (below), one of the most common species. Also known as the Atlantic bottlenose dolphin, these marine mammals can be found around the world in temperate and tropical waters. Bottlenose dolphins can grow to a whopping twelve feet long (3.5 meters) and weigh up to 1400 pounds (635 kg). Coastal dolphins are smaller and a lighter shade of grey than their darker, larger relatives that live further out to sea.

Photo credit: Joachim S. Muller, https://www.inaturalist.org/photos/9420228
Photo credit: Joachim S. Muller, https://www.inaturalist.org/photos/9420228

Bottlenose dolphins are generalists, meaning they are not picky eaters. Like radar, dolphins use sound, or echolocation, to find their prey. Once located, dolphins may stun fish with a quick strike from the fluke or flipper, a behavior known as “fish whacking.”

Rising temperatures due to climate change may threaten dolphins by changing the distribution of their prey, or by altering how far dolphins need to migrate to feed and reproduce. Additionally, higher temperatures may interfere with dolphins’ ability to thermoregulate, or maintain a constant body temperature. The bottlenose dolphin is listed as a species of “Least Concern” on the International Union for Conservation of Nature’s Red List since it is widespread and abundant. However, they are protected by the 1972 Marine Mammal Protection Act, as well as other regulations from the National Marine Fisheries Service.

To learn more about bottlenose dolphins, check out these links:

www.nsrl.ttu.edu/tmot1/turstrun.htm

http://www.nmfs.noaa.gov/pr/species/mammals/dolphins/bottlenose-dolphin.html

http://www.dolphins-world.com/dolphin-intelligence/

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: Cole Birmingham and Matthew Hyde

Contributing Professor: Dr. Lisa Campbell

Editor: James M. Fiorendino

Climate Spotlight: Humpback Whale

Featured image from: https://qz.com/902840/scientists-finally-figured-out-why-whales-leap-into-the-air/

When you hear “majestic songs” and “aerial acrobatic abilities”, you might be thinking of Olympic athletes or circus performers, or you might be thinking of one of the largest animals on the planet: the Humpback Whale. These marine mammals are known for their spectacular breaching behavior, leaping high out of the water and crashing back down. Humpback whales live in all major oceans, ranging from the equator to subpolar latitudes, and have one of the longest migration routes of any mammal, traveling from tropical to polar waters. Humpback whales, shown in Figure 1, are primarily dark grey, with some patches of white. Their tail fins, or flukes, have distinct pigmentation patterns which can be used to identify individuals, like fingerprints are used to identify humans. Humpbacks can be up to 60 ft long (18 meters) and weigh between 25-40 tons (23 – 36,000 kg).

Figure 1: Physiology of humpback whales. From: https://phys.org/news/2015-12-whales-threat-climate-impacts-migration.html
Figure 1: Physiology of humpback whales. From: https://phys.org/news/2015-12-whales-threat-climate-impacts-migration.html

Currently, climate change is threatening Humpback Whales by altering their food supply and migratory behavior. As ocean temperatures rise, Humpback whales are tricked into migrating earlier and traveling farther. Humpbacks migrate to Antarctica to feed on krill, tiny shrimp-like crustaceans. Decreasing krill abundance in Antarctica due to climate change has negative impacts on the survival of Humpback calves.

Of the 14 distinct Humpback whale populations (Figure 2), 1 is threatened and 4 are endangered. In the United States efforts have been made to protect these iconic marine mammals through the Endangered Species Act and the Marine Mammal Protection Act, which prohibits the capture of marine mammals in United States waters.

Figure 1: Global distribution of humpback whale populations. From: http://www.nmfs.noaa.gov/pr/species/mammals/whales/humpback-whale.html
Figure 1: Global distribution of humpback whale populations. From: http://www.nmfs.noaa.gov/pr/species/mammals/whales/humpback-whale.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.

To learn more about Humpback whales, check out these links:

https://www.federalregister.gov/documents/2016/09/08/2016-21276/endangered-and-threatened-species-identification-of-14-distinct-population-segments-of-the-humpback

Script Authors: Karen Ramirez and Raley Roberts

Contributing Professor: Dr. Lisa Campbell

Editor: James M. Fiorendino

Climate Spotlight: Minke Whales

Featured image from: https://oceanwide-4579.kxcdn.com/uploads/media-dynamic/cache/widen_1600/uploads/media/default/0001/05/thumb_4330_default_1600.jpeg

What would you do if you knew that your home was at risk of melting away? This is the problem that Antarctic Minke whales face due to Earth’s changing climate.

Minke whales, which grow to roughly 30 feet (10 m), are the smallest of the great whale species, which include blue, humpback, and sperm whales. Increasing temperatures have the potential to jeopardize the survival of Antarctic Minke whales through the melting of ice, an important component of the Antarctic ecosystem. Less ice means less food for the minke, which feed primarily on the millions of krill that share the icy Antarctic waters. Krill consume microscopic algae found on the underside of sea ice; a warming atmosphere means that the total surface area of sea ice will likely shrink, ultimately limiting the food supply of both krill and the Minke whale.

Fig 1: The above map shows the distribution of Minke whales globaly. From: http://us.whales.org/sites/default/files/styles/content_full/public/species/maps/map_antarcticminke_w.png?itok=4FxLbdd9
Fig 1: The above map shows the distribution of Minke whales globaly. From: http://us.whales.org/sites/default/files/styles/content_full/public/species/maps/map_antarcticminke_w.png?itok=4FxLbdd9

Studies of Antarctic ecosystems show that Minke whale numbers are declining, most likely due to habitat loss and shortage of food supply due to a warming climate. Luckily, abundance estimates suggest the Minke whale population is not endangered. Though Minke whales are protected by the International Whaling Commission moratorium, which prohibits the harvest of Minke and other whales, some countries still hunt them under the guise of scientific, subsistence, or cultural whaling.

To learn more about Minke whales, check out these links:

https://oceanwide-expeditions.com/to-do/wildlife/minke-whale

http://us.whales.org/species-guide/antarctic-minke-whale

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: Kendall Polk & Miranda Hooper

Contributing Professor: Dr. Lisa Campbell

Editor: James M. Fiorendino

Climate Spotlight: Narwhal

Featured image from: https://www.climate.gov/news-features/features/narwhals-tale-surviving-sea-ice-change

Have you ever heard of the “unicorn of the sea?” Unlike its mythical land dwelling counterpart, the narwhal is a very real species; a unique type of toothed whale known for the large tusk protruding from its head. A Narwhal’s tusk is actually an enlarged tooth that can grow up to 9 feet or more, complete with about 10 million nerve endings. Males utilize the tusk for friendly contact, dueling, or cleaning. Female narwhals rarely have a tusk. Narwhals are a migratory species that live in the Atlantic and Russian Arctic. During the summer they tend to stay near the shore before migrating below pack ice for the winter months.

In the Narwhal’s icy habitat, the simple but essential act of breathing can be a challenge. Narwhals are dependent on the presence of holes in sea ice, which provide a place to breath and rest in an otherwise ice-covered ocean. Climate change may be interfering with the ability of Narwhals to locate these critical ice holes. Additionally, increasing temperatures may alter the timing of Narwhal migrations, causing this marine mammal to stay in their summer territory for too long. When they finally begin to migrate, many of the ice holes on their migratory route will have closed, leading to entrapment and death of Narwhals. As ice holes become too distant from one another, Narwhals are left to either drowning while attempting to find another ice hole, or starve to death remaining at an existing hole. Increasing mortality, or death rate, is concerning for Narwhals because of their low fecundity, or reproductive rate.

NarwhalinIce_HR
A lone narwhal is spotted in this image captured by a survey plane. In this extreme environment, the narwhal is surrounded by ice of varying density. Image from: https://www.climate.gov/news-features/features/narwhals-tale-surviving-sea-ice-change

To learn more about narwhals, check out these links:

https://staff.washington.edu/klaidre/narwhalfaq.html

https://www.climate.gov/news-features/features/narwhals-tale-surviving-sea-ice-change

https://www.worldwildlife.org/stories/unicorn-of-the-sea-narwhal-facts

http://www.defenders.org/narwhal/basic-facts

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: Chris Coffman and David Dodge

Contributing Professor: Dr. Lisa Campbell

Editor: James M. Fiorendino