We have been seeing high levels of plankton in our water lately. Many Aquarium exhibits were a bit cloudy last week from all the algae and other planktonic organisms that are becoming more numerous as the season progresses.
Salt and pepper sea cucumber
Creeping pedal sea cucumber
Suspension-feeding animals, meaning animals that feed on material that’s suspended in the water, really shine during plankton blooms. Many of our sea cucumbers, hydroids, bivalves (clams, scallops, and mussels) and barnacles have been very visible during this time. When white, salt and pepper, burying or creeping pedal sea cucumbers sense high levels of plankton, they unfurl their feeding tentacles and start pulling in suspended material from the water. Barnacles extend their cirri (modified feet) into the water and literally comb out the plankton, pulling it into their test (shell) down to the mouth inside.
Other animals, such as pink-lipped hydroids, are seasonal—only appearing in our exhibits from about mid-April through September. The hydroids are only about half an inch high at present, but will soon expand to about one and a half inches in length. These colonial animals have stinging cells, or nematocysts, that capture tiny zooplankton from the water. They, in turn, will attract their own predators, small nudibranchs that come in with the water from about May through August to feed on the hydroids.
A Dungeness crab
This culinary term refers to any crab that has just molted its old exoskeleton and is still soft and flexible on the outside. The species most commonly sold as soft-shell crab in the U.S. is the blue crab, Callinectes sapidus, which has the convenient habit of mass molting between April and September on the East Coast.
The back of a crab’s carapace popping up (as shown by the green arrow)
A crab with a new, pale-colored exoskeleton
At any time in its life, a crab has two exoskeletons—the one we see on the outside and another one just underneath it, which is always in the process of growing. A few days before the old exoskeleton is shed, the crab stops eating. Hormones, directed by the eyes of the crab, initiate the separation of the outer from the inner exoskeleton and from the fleshy part of the crab. Within a few days, the back of the crab’s carapace pops up and the crab pulls itself out, completing the molt. The new exoskeleton hardens over the next several hours to several days; during this time, the crab sucks up water to expand the new pale-colored exoskeleton.
Robert W. Davidson, President & CEO, Seattle Aquarium; Stephanie Kornblum, Harbor Seal Capital Campaign Chair; Dan M. Guy, III- Co-Chair, SeaChange Breakfast; Ted Ackerley- Co-Chair, SeaChange Breakfast — at Four Seasons Hotel Seattle.
The Seattle Aquarium held the first of what will be an annual fundraising breakfast, SeaChange, on April 23. Over 200 guests joined us to support our Harbor Seal Capital Project, generously donating over $183,000 toward the beautiful new exhibit that’s currently being constructed for Barney and his pool-mates. The event’s keynote speaker—Jim Toomey, creator of the nationally syndicated, marine-themed comic strip “Sherman’s Lagoon”—proved to be a big hit as he created a series of custom animal sketches.
View this video to see how much we appreciated the support, and see photos from the event on our Flickr page.
Picture of the Duwamish Valley taken by Paul Joseph Brown
Right across Elliott Bay from the Seattle Aquarium is the mouth of Seattle’s only river, the Duwamish River. Did you know that the Lower Duwamish is a Superfund site? Declared by the U.S. Environmental Protection Agency (EPA) in 2001, this designation means the site is extremely contaminated by pollution and needs to be cleaned up for wildlife and human health.
The Aquarium is encouraging members of our community to learn more about the EPA’s proposed cleanup plan, and to voice your opinion on it. The EPA is hosting public hearings on April 30, May 15 and May 29. The Duwamish River Cleanup Coalition (DRCC), EPA’s designated Community Advisory Group and a partner of the Seattle Aquarium, is hosting more public meeting, workshops, boat tours and events.
Visit the DRCC’s website for resources regarding the EPA’s proposed cleanup plan for the Lower Duwamish. More details can also be found in a recent article by Seattle Times reporter Lynda Mapes.
Harbor seal, Q from the Seattle Aquarium
We are excited to learn from the Point Defiance Zoo & Aquarium that one of their harbor seals is pregnant and a second may possibly be expecting as well! Our harbor seal, Q, who is living at the Point Defiance Zoo & Aquarium as part of a breeding exchange, is the father.
Harbor seal, Qilak from Point Defiance Zoo & Aquarium
Qilak’s (pronounced Kee-lak) impending pup delivery is confirmed by ultrasound.
Harbor seal, Shila from Point Defiance Zoo and Aquarium
Shila (pronounced Shi-lah) is thought to be pregnant, but she is reluctant to have a probe placed on her abdomen, and veterinarians have been unable to verify a pregnancy with ultrasound. Her weight and behavior are pointing towards pregnancy.
The pups are expected in June but a precise due date can’t be determined since harbor seals have a period of delayed implantation of the fertilized egg, which means gestation can range from 9 to 11 months.
In the wild, harbor seals generally have one pup per year.
Q, who is 14 years old, came to Tacoma from the Seattle Aquarium a year ago as part of a cooperative Species Survival Plan breeding program. Qilak, 9, and Shila, 8, were both born in the wild. They came to Point Defiance Zoo & Aquarium in 2009 from Alaska Sea Life Center. You can see them all in the facility’s Rocky Shores exhibit!