Forecast: cloudy with a touch of sediment

Cloudy Exhibit

Why is the water in the Seattle Aquarium’s exhibits sometimes a bit cloudy? Because it’s pumped directly from Puget Sound, where the underwater weather report has recently included (in addition to 100% humidity) colder temperatures and partially cloudy waters. With continued winter rain events on the horizon, we can expect to see less-than-crystal-clear water in our exhibits many more times this year.

This begs the question: what causes the water in the Sound to get cloudy? Seasonal rains and wind stir up sediment from the bottom of local rivers; the sediment is then carried down to Puget Sound, where it causes reduced visibility. This is a natural cycle that provides nutrients (like carbon and nitrogen) to Puget Sound. Read on for answers to some common questions we’ve received about our cloudy water.

Does the Aquarium have a filtration system?

The pumps off Pier 59 bring in over 4,000 gallons of saltwater from Elliott Bay every single minute. That water goes through various sand filters, UV filters and coolers depending on the destination. Despite all that, the water in our exhibits still provides a very good indication of what water conditions are like out in Puget Sound. When it’s cloudy in the Sound—it’s cloudy in our exhibits.

How does this affect animals in the Sound?

These seasonal rains are helpful to adult salmon! When salmon are born, they imprint on the scent of their home stream, since each river and stream has a distinct chemical “fingerprint.” These seasonal rains wash the scent of the river downstream, helping to lead adult salmon home.

Is it pollution?

Though the cloudiness is not pollution, it is a good reminder that all the rain from our streets and neighborhoods washes down to the Sound, either directly or through storm drains. No matter where you live, all drains lead to the ocean.

Here are a few ways you can help keep the Sound clean:

Remember that untreated water from storm drains goes directly into Puget Sound, right into the homes of our underwater neighbors. We can carefully dispose of chemicals and fertilizers and pick up after our pets to keep Puget Sound clean. Also, keep your car tuned up to ensure that leaking oil and chemicals don’t get washed into the Sound—and wash it at environmentally friendly carwashes.

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Here comes Hogan!

We’re thrilled to introduce the newest Seattle Aquarium resident, Hogan the harbor seal! Hogan arrived on Tuesday, December 8 after moving from his previous home at the Point Defiance Zoo & Aquarium (PDZA), where he was born on June 2, 2013.

Hogan is actually returning to his roots by coming to the Seattle Aquarium—his father is our very own Q! Here’s the backstory on that: The Seattle Aquarium and PDZA, both accredited members of the Association of Zoos & Aquariums (AZA), participate in the organization’s harbor seal Species Survival Plan (SSP). As part of the SSP, Q was transferred to PDZA in April 2012 on a breeding loan. While there, he sired two pups with two different females: Shila, Hogan’s mother, and Qilak, who gave birth to a pup named Saya.

At two and a half years old, Hogan is gray with light gray spots. His weight varies seasonally, but he’s still growing and currently weighs 121 pounds. Along with Q and Barney, he’ll enjoy a diet composed of a variety of fish including herring, capelin, mackerel and squid. Like his weight, his diet will fluctuate seasonally and range between six and 15 pounds of food per day. He was named after Holly Hogan Reed, a beloved veterinarian at PDZA who passed away in 2012.

Come say hello to Hogan during your next visit to the Seattle Aquarium! And read our harbor seal fact sheet for more information about these charismatic animals.

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Ectotherms vs. endotherms

Do you know the difference between an ectotherm and an endotherm—or even what these terms mean? They both refer to the ways that animals stay warm. When the weather outside is frightful, a blog post about thermoregulation is so delightful! Keep reading to find out which animals need help from the environment to stay warm (ectotherms), and which animals produce their own heat (endotherms).


For these animals, heat comes from outside (ecto-) their bodies—their environment provides their warmth. That means they require less food, and are consequently able to inhabit places that would be off-limits to endotherms. However, their activity level is limited by the surrounding conditions. If it gets too cold, they simply can’t move.

Banggai cardinalfish (Pterapogon kauderni)

Like most fish, Banggai cardinalfish are ectotherms. Because of this, these fish appear less hungry during winter months.

Banggai cardinalfish

Widehand hermit crabs (Elassochirus tenuimanus)

Hermit crabs, along with all invertebrates, are ectotherms. Since invertebrates account for more than 95 percent of animal species, that means that most animals are ectotherms

Widehand hermit crab

Tripod fish (Family Ipnopidae)

These fish live in the abyssal zone, where conditions are so stable that their body temperatures don’t change.

Tripod fish


These animals produce their own heat inside (endo-) their bodies. Creating that warmth speeds up their body processes: muscles, neurons and all of their processes work faster. That also means they require a lot of food—between five and 20 times more food than an ectotherm of the same size!

Sea otters (Enhydra lutris)

These marine mammals have to eat roughly 25 percent of their body weight per day to keep their bodies warm.

Sea otter

Anna’s hummingbirds (Calypte anna)

These high-energy birds have needs that can’t be met at night when they’re at rest. The solution? Torpor, a state of deep sleep and lowered metabolism. Some animals extend torpor over the whole winter; this is called hibernation.

Anna's hummingbird

Opahs (Lampris guttatus)

These fish generate heat mainly by constantly flapping their pectoral fins, which helps their bodies stay warmer than the water even when they dive over 1,500 feet below the surface. Opahs have been sighted in Washington waters twice since 1935.


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Ominous and obscure animals at the Seattle Aquarium

Just in time for Halloween, here’s a peek at some of the creepy creatures on exhibit at the Seattle Aquarium. Get to know them here, then come check them out in person during your next visit!

Creeping pedal sea cucumber

Creeping pedal sea cucumber, Psolus chitonoides

This scaly echinoderm can be found creeping along in our Puget Sound Fish and octopus exhibits. It uses its oral tentacles to ensnare detritus floating in the water; however the tentacles themselves contain a toxin to deter any potential predators of the cucumber itself.


Sablefish, Anopoploma fimbria

Something about those beady eyes makes this fish look a little creepy! But many find it mightily tasty too—and may know it by its other common names: butterfish and black cod.

Red brotula

Red brotula, Brosmophycis marginata

This deceptive fish is longer than it appears and uses slime to protect itself from predators. Although unknown to many visitors, it’s been living in our Puget Sound Fish exhibit for over 10 years. A recent den rearrangement makes its hiding place slightly more visible.

Spotted ratfish

Spotted ratfish, Hydrolagus colliei

This cartilaginous fish is a marine-world Frankenstein, appearing to have the head of a rabbit, the body of a fish and the tail of a rat. There are dozens of species of ratfish in the Order Chimaera. In Greek mythology, the Chimera was a monster with the head of a lion, body of a goat and tail of a serpent. Other names for ratfish include ghost shark and spookfish. Learn more about them here!

Devil scorpionfish

Devil scorpionfish, Scorpaenopsis diabolus

This motionless, amazingly well-camouflaged fish could easily sneak up and scare you. With venomous spines, a downturned mouth and those eyes—there’s just something about them!

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Halloween quiz: poisonous vs. venomous sea creatures

With the celebration of ghosts, goblins and things that go bump in the night nearly here, there’s no better time to talk about poisonous and venomous critters at the Seattle Aquarium. Do you know the difference between poison and venom? Most people associate venom with snakes, which provides a good hint about the correct answer to our question: venom is always delivered via a wound (a sting or a bite, for example), while poison is ingested, inhaled or absorbed through the skin.

Both poison and venom contain both contain toxins, which sea creatures use to catch prey and/or defend themselves. Toxins are molecules, often in a cocktail of combinations that may affect the nervous system (neurotoxins), overstimulate the immune system (allergens) or even eat away at the flesh (proteolytic toxins)!

Do you know what animals at the Seattle Aquarium are poisonous and which are venomous? Test your knowledge below!

Sea anemone:

sea anemone




Venomous. A rockfish’s dorsal, pelvic and anal spines all contain a mild venom.

Sea urchins:

Sea urchins

Gotcha! Local sea urchins, like those on exhibit at the Aquarium, have long, sharp spines but don’t produce toxins. Some tropical species of sea urchins are venomous, however.




Cabezon eggs:


Poisonous. If you ate cabezon eggs, although we can’t imagine why you’d want to, you could experience nausea, diarrhea or—at the extreme end—go into a coma. It’s thought that the poison in these eggs may be an adaptation to provide protection after they’re laid, typically in shallow water.



Venomous—but not poisonous, so this fish is actually recommended for human consumption in many areas.



Venomous. An octopus bites with its beak, then injects venom into the wound via its saliva.

Puffer fish:

Puffer fish

Poisonous. Tetrodotoxin is what makes the puffer fish poisonous—it’s the same toxin found in blue-ringed octopuses, which are venomous (one of the marine world’s most venomous animals, in fact, and NOT on display at the Seattle Aquarium!).


Moon jellies

Venomous. Moon jellies, like those found in the Ring of Life exhibit at the Seattle Aquarium, deliver a mild sting to humans that results in little to no reaction.

Moray eel:

moray eel

Gotcha again! Moray eels can deliver a very painful bite but aren’t venomous.


Get to know more about these animals on your next visit to the Seattle Aquarium!

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