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/.

Harbor Seal Pups in Tomales Bay

Harbor seal pup hidden amongst the rocks
Photo by Todd Johansen 2011

            While paddling close to shore north of White Gulch, looking for a sea star or two, our Saturday kayak tour suddenly stumbled upon a grey and white harbor seal pup resting on the shore, tucked into the rocks. While this offered us a rare opportunity to see a pup up close, it was important that we quickly move along and leave the pup alone.

            As humans, our first instinct is to help the little guy, assuming that it has been abandoned or is sick. In actuality, mother harbor seals often leave their pups on shore for periods of time. The mother seal needs to hunt to provide sustenance for herself and for her pup, but cannot effectively snag a meal if the pup is tagging along, slowing her down. Therefore, the mother tucks the pup away, hidden amongst the shoreline, and returns in a couple of hours, once she has caught enough to eat.

            In Point Reyes, Drakes Estero is a popular pupping ground for harbor seals. It is protected March through July and access routes to the pups are closed off to protect the pups and mothers from human disturbance. Smaller numbers of pups can also be found in Tomales Bay, however, and only a few certain areas are protected, so it is important to be aware when paddling in the bay, what to do if you see a harbor seal.

            If you see a harbor seal pup along the shore in Tomales Bay, do not approach it. Quietly move away from the seal, as human presence will not only cause stress for the pup, but will prevent the mother from returning.

            The east shore of Hog Island is a popular haul out spot for harbor seals in the bay. It is illegal to land on the east side of the island, or to approach close enough to cause disturbance to the hauled out seals. It is important for them to haul out on land so that they can rest and regulate their body temperature. They also use haul out sites to give birth and to nurse their young. Human activity too close to harbor seals causes them to “flush” or rush into the water. If they are flushed often enough, they will abandon favorite haul out sites or even their young pups.

            Harbor seals are common this time of year in Tomales Bay, and can often be seen swimming near Hog Island. Even while staying clear of Hog Island, a kayaker can get an up close and personal view of a harbor seal as the curious animal swims by and investigates the boat. They feel much more comfortable in the water, and will get quite close to a kayaker, or follow the boat for a short distance.