Creature Feature: Pacific White-Sided dolphin

Davidson Seamount: Exploring Ancient Coral Gardens: January 26 L

Image ID: anim0912, NOAA’s Ark – Animals Collection Location: California, Davidson Seamount Photo Date: 2006 January 26 Credit: Image courtesy of NOAA/MBARI 2006.

Streaks of grey speeding through the ocean, jumping, twirling, playing, and smiling – these creatures know how to have fun! That’s what Marilou, MSI’s Executive Director, loves about the Pacific White-Sided dolphin, Lagenorhynchus obliquidens. They will live and play together in groups called pods.  Pods can range in size from 10 to one hundred, even to thousands of dolphins in the temperate waters of the North Pacific. You can even find them swimming with other species of cetaceans (whales, dolphins, or porpoises).  Dolphins are very social so if you spot one dolphin at the surface of the water, you can be sure that there are many more hidden beneath the waves.

The Pacific White-Sided dolphin can be distinguished from other species by their body structure and color patterns. The beak is short, round, and black on the tips. The fluke (which is the tail) is also black. It’s body is mostly dark-gray with a white underside. Adults can reach 7-8ft long and about 300 pounds. White-Sided dolphins have a unique dorsal fin (that’s the one on the top) with white stripes on both sides.  Their dorsal fins are larger and more severely curved than those of other dolphins.

When dolphins get hungry, they rely on teamwork to fill their bellies.  Like a football team running a play, the pod members will corral schools of small fish and then each dive through the school to grab a bite.  In addition to munching a mackerel or two, dolphins also eat squid. Some scientists hypothesize that dolphins they mostly feed at night when the squid rise to the surface of the water.  Late night calamari anyone?

Working as a team helps dolphins to survive but it can’t always protect them from ever-growing human activity in the ocean. Though dolphins are not commercially hunted anymore, many still fall victim to large fisheries.  Japanese, Korean, and Taiwanese fisheries target squid with their gillnets and driftnets that drag through the water.  Animals like dolphins can be unintentionally snared by these nets, injuring and killing them.  When this happens, these creatures are known as bycatch and are a major conservation issue.  The Pacific White-Sided Dolphins are protected under the Marine Mammal act but are considered low-risk-least concern under The International Union for Conservation of Nature and Natural Resources (IUCN).  Here are some links to learn more about bycatch and how to protect vulnerable marine creatures:

http://wwf.panda.org/what_we_do/endangered_species/cetaceans/threats/bycatch/

http://oceana.org/en/our-work/promote-responsible-fishing

http://ocean.nationalgeographic.com/ocean/take-action/sustainable-seafood/

Reference:

Edited by KC O’Shea

Image: http://www.photolib.noaa.gov/htmls/anim0912.htm

http://www.nmfs.noaa.gov/pr/species/mammals/cetaceans/whitesideddolphin_pacific.htm

http://acsonline.org/fact-sheets/pacific-white-sided-dolphin/

http://www.marinemammalcenter.org/education/marine-mammal-information/cetaceans/pacific-white-sided-dolphin.html

http://marinebio.org/species.asp?id=353

http://www.arkive.org/pacific-white-sided-dolphin/lagenorhynchus-obliquidens/video-06a.html

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