Northern Elephant Seals at Chimney Rock

Bulls, cows, and pups at Chimney Rock
Photo by Casey Brechbill, 2011, All Rights Reserved. 

Northern elephant seals are amazing creatures.  They spend 80% of their life in the open ocean and most of that time is spent underwater.  They have the farthest migration of any mammal on land or sea because they migrate twice each year!  Northern elephant seals spend the year travelling from the beaches where they breed and have their pups to their feeding grounds far out in the Pacific Ocean, back to the beaches to molt, and then back to their feeding grounds.

Since 1981, when the first breeding pair returned to the Point Reyes National Seashore, the population of northern elephant seals at Chimney Rock has grown by leaps and bounds.  Though they have been seen at Chimney Rock year-round, the best time of year to see them is between December and March, when the seals return to Point Reyes to breed.

While at sea, elephant seals spend much of their time diving for food.  They can dive as deep as 5000 feet and stay down for 40 minutes!  Their normal dive is between 1,000 and 2,000 feet deep, where there are few other predators competing for the same food.  To dive this deep, elephant seals store extra oxygen in their blood, collapse their lungs, and slow their heart rate down to about 10% of normal.  Elephant seals eat fish, squid, octopus, and small sharks.

Bulls often have wounds around their neck from fights. 
 Photo by Casey Brechbill, 2011, All Rights Reserved.

Because they spend so much time in cold water, northern elephant seal s have a thick layer of blubber, or fat, under their skin.  In the 1800’s, northern elephant seals were hunted almost to extinction for their blubber, which was used for lamp oil.  In the 1920’s, Mexico and the United States banned the hunting of elephant seals.  The species has made an amazing recovery, from less than 100 animals to over 100,000.

There is still plenty to learn about elephant seals.  Until recently, much of what was known about them came from studying animals that were deceased.  With improvements in technology, researchers have been able to learn much more.  Northern elephant seals have been fitted with satellite and radio tags as part of the Tagging of Pacific Predators (TOPP) study.  Attaching a tag to a female elephant seal that weighs between 1,000 and 2,000 pounds is quite a process! Studies like these help researchers learn more about elephant seals and about the ocean environment that they travel through. 

Males have an extra large nose and are much larger than females.  
Photo by Casey Brechbill, 2011, All Rights Reserved.

 There are several places to see elephant seals in Point Reyes.  For some of the best viewing, take a drive out to Chimney Rock and walk on the paved trail to the Elephant Seal Overlook.  On weekends and holidays during peak viewing season, the Park operates a shuttle bus service between the Ken Patrick Visitor’s Center at Drakes Beach and Chimney Rock and the Lighthouse.  More information on the shuttle bus can be found here: http://www.nps.gov/pore/planyourvisit/shuttle.htm

For more information on these fascinating mammals, visit our sources: http://www.nps.gov/pore/naturescience/elephant_seals.htm  or  http://topp.org/species/elephant_seals

Sea Nettles!

Sea Nettles are a type of jellyfish found along the California coast.

 Watching jellyfish float and swim in an aquarium is often a relaxing experience, but finding them washed up on a beach or swimming next to you can be anything but soothing. We have several types of jellies in northern California waters, and sometimes swarms of them will be washed up onto beaches. Recently, Sea Nettle jellies (Chrysaora fuscescens) have been washing up onto the beaches of Tomales Bay, which is unusual for this time of year.


Sea Nettles washed up
on Heart's Desire Beach,
Tomales Bay State Park



Though much is known about jellies in captivity, scientists are still studying how jellyfish populations behave in the wild and why we have been seeing larger numbers of them in recent years in the water and washed up on the beach. Jellyfish can swim, but spend most of their time drifting with the currents. As they get closer to shore, large swells or high tides will wash them up onto the beaches, where they die.

Sea Nettles are one of the types of jellyfish that we see in Tomales Bay. They usually live in the open ocean along the coasts of California and Oregon during spring and summer, then move into shallower bays for the fall and winter. The bell, or top part of the Sea Nettle, grows over 17 inches across. The four oral arms, the furry-looking tentacles underneath, can be up to 15 feet long. They have 24 thin brown tentacles hanging from the bell that capture and paralyze their food. They eat young fish, zooplankton, and other jellies. Marine animals such as birds and turtles eat Sea Nettles and are not hurt by their sting. Small crabs will sometimes hitch a ride on Sea Nettles as they move through the ocean. Sea Nettles only live 6 to 12 months in the wild.

Jellyfish have stinging cells called nematocysts. Thousands of these cells line each tentacle, and they react to pressure. The stinging cells shoot out a barb attached to a thread, much like a harpoon, which hooks into prey to keep it from swimming off. Because the sting is an automatic reaction, the cells can still fire even after the jelly has died or the tentacle has been broken off. Sea Nettle stings in people rarely require medical attention, but they can be quite painful, so don’t touch! If you are stung, rinse the area with saltwater first to try and remove all parts of the tentacle. A vinegar rinse can sometimes reduce the pain of the sting, but do not use fresh water or urine, as these can make the sting worse. If you have any doubts about the severity of the sting, seek medical attention.

Sea Nettles are beautiful jellies in the water or washed up on the beach, as long as you do not touch the stinging cells. Want to know more? Check out our sources: http://jellieszone.com/, http://montereybayaquarium.com/animals, and http://zoo.pgh.pa.us/.