Fish Archives - Seattle Aquarium

What makes a healthy ecosystem? A corpse, of course!

Posted on October 21, 2024October 21, 2024 by Emma Leiser

During Halloween, skeletons and other dead creatures make for great decorations. But did you know corpses play important roles in aquatic ecosystems year-round?

When animals die, their bodies are still full of nutrients. Nutrients are chemical substances that help living beings grow, repair themselves or maintain life. Humans need nutrients like carbohydrates, proteins and minerals.

Nature is not wasteful and there are many ways these nutrients can pass to other parts of the ecosystem. If an apple falls from its tree, straight to the ground, an animal might come along and gobble up its nutrients. Or the fruit might stay there and decomposers like worms, fungi and bacteria will help return its nutrients to the nearby soil.

Animal carcasses end up in similar scenarios: Someone eats them or they decompose into their environment. Often, both happen with the same carcass! Here are three fascinating types of marine corpses that play key roles in their ecosystems.

Night of the living salmon

Pacific salmon embark on the journey of a lifetime when they travel back from the ocean to the freshwater rivers and streams where they were born so they can reproduce, or spawn. When salmon return to rivers, their bodies bring with them important nutrients from the ocean. Along the way, some salmon are eaten by predators, who eagerly take in those nutrients for themselves.

After spawning, Pacific salmon naturally die and their carcasses feed many animals, including bears, wolves, small mammals, birds and insects. Those land-based animals can further pass nutrients from salmon to their environment through their waste. Whatever part of the salmon carcass is left over also gets broken down by microbes and erosion, giving nutrients to the surrounding soil and plant life. Salmon play a key role in supporting tree growth near riverbeds.

The nutrients from salmon have a distinct isotope signature that scientists use to track salmon’s impact in the local ecosystem. Researchers found that nutrients from salmon in Washington ended up in over 100 species of microbes and animals. The nutrients can reach animals up to seven miles away from their stream of origin.

During late summer and early fall, you can join Seattle Aquarium naturalists on the Cedar River to observe salmon. Because the Cedar River Salmon Journey occurs during the final days of salmon reproduction, we often see their carcasses along the river. And you can see salmon year-round, at various stages in their growth, on a visit to the Seattle Aquarium.

Creepy deep-sea feast

The massive, decaying corpse of a marine goliath would be hard to miss. Whale carcasses that wash up on shore are a big deal. And miles below the ocean’s surface, the scavengers and decomposers who live in the deep, dark waters of the seafloor also take notice.

When whales die in open waters, their bodies sink down to the bottom and end up as a buffet for these creatures of the deep, feeding them for years or even decades. This phenomenon is called a whale fall.

Entire ecosystems can pop up around whale carcasses. Different creatures feast on the carcass during different stages of its decomposition. The first to move in are the scavengers, including crabs, lobsters, sharks, octopuses and eels. These animals eat the whale’s meat and other soft tissue. When they’re done, other creatures like worms and snails move in to have their fill. Bone-eating bacteria and other microbes will spend years on the remaining skeleton. Nutrients from the carcass also enrich the seafloor’s surrounding sediment.

It’s rare for scientists to come across a natural whale fall. To study them in greater detail, researchers will sometimes intentionally sink whale carcasses that wash ashore. Now that’s an experiment that would make Frankenstein jealous!

Marine snow, seen here in the Gulf of Alaska, is made of “flakes” of bits of animal carcasses, dead plants, feces and sand, among other materials, that fall down to the seafloor. Video courtesy of NOAA/UAF/Oceaneering.

A ghostly snowfall

Snow in October? It might not be happening in Seattle, but down in the ocean’s depths, flurries of white are the norm. Marine snow is made of tiny plant-like organisms called phytoplankton combined with small bits of natural materials. That includes pieces from animal carcasses along with dead plants, animal feces and sand. When drifting through the water, these tiny specs look like the snow we see on land.

Like whale corpses, marine snow drifts downward. The snow “flakes” get larger as they go, gaining speed, but they still take weeks to reach the seafloor.

Along the way, some of the snow will be eaten by fish or marine mammals near the top or middle of the water column. Many benthic creatures, which are animals that live on the seafloor, rely on marine snow as a food source. They may filter the snow from the water directly or scavenge for it on the seafloor.

Uneaten marine snow accumulates in the “ooze” that covers the seafloor. And the bone-white snow also dusts the sunken ships and other marine debris of the ocean’s graveyard.

While corpse stories make for a frighteningly fascinating Halloween read, animal carcasses support living creatures all year long. With death, comes the chance for life to flourish. You can check out hundreds of types of thriving marine life at the Seattle Aquarium. Plan your visit today!

The doctors (and techs) are in: Getting to know the Seattle Aquarium’s veterinary care team

Posted on February 20, 2024April 11, 2024 by Emma Leiser

This story is part of our series, The Doctor Is In—highlighting our veterinary team’s expertise in service of animal wellbeing.

Providing medical care for the animals at the Seattle Aquarium—soon to be nearly 18,000 with the opening of the Ocean Pavilion!—is far from a one-person endeavor. Working to provide excellent animal health and wellbeing requires skill and expertise from a well-rounded veterinary team, one that is required to be available any time of the day or night, every day of the year.

The Seattle Aquarium’s veterinary care team is currently composed of six people:

Two full-time veterinarians—Our director of animal health and team leader, Dr. Caitlin Hadfield, MA VetMB MRCVS DiplAZCM DiplECZM and Dr. Sasha Troiano, DVM MS CertAqV;
Two relief veterinarians, who are available to step in when our staff veterinarians are unavailable and/or extra support is needed—Dr. Brian Joseph, DVM MFAS CertAqV and Dr. Alicia McLaughlin, DVM CertAqV; and
Two veterinary technicians*—Lindy McMorran, BS LVT Cert AqVN/T and Erika Russ Paz, BS LVT.

*Not sure what a veterinary technician is? Be on the lookout for our upcoming web story, in which we’ll introduce you to Lindy and Erika and share some highlights of what they do—as well as details about a prestigious new credential that Lindy recently earned!

Initials = hard-earned credentials

Did you happen to take in the initials following our vet team’s names? They’re credentials—each one representing extensive education and certification.

For instance, staff vet Dr. Sasha Troiano and relief vets Dr. Brian Joseph and Alicia McLaughlin have doctorates of veterinary medicine, or DVMs. The three also have certified aquatic veterinarian (CertAqV) credentials from the World Aquatic Veterinary Medicine Association (WAVMA), indicating their extensive experience working with aquatic animals. In addition, Dr. Troiano has a Master of Science (MS) degree; Dr. Joseph has a Masters of Fisheries and Aquatic Sciences (MFAS) degree.

Lindy McMorran and Erika Russ Paz have Bachelor of Science (BS) degrees—marine biology for Lindy; marine science with a minor in biology for Erika—and licensed veterinary technician (LVT) credentials. In addition, Lindy recently received a certified aquatic veterinary nurse/technician (CertAqVN/T) credential from WAVMA—more on that in our upcoming web story!

As for Dr. Hadfield’s credentials, we’ll let her explain them in her own words:

MA: “I did a bachelor’s degree in zoology that included a master’s.”
VetMB: “Then I did my vet degree, which goes by those initials at University of Cambridge —the initials vary a bit by school.”
MRCVS: “That means I’m in good standing as a member of the United Kingdom’s Royal College of Veterinary Surgeons. It’s an odd requirement from England!”
DiplACZM: “These letters are for board certification. This was my first one, with the American College of Zoological Medicine—that’s what the ‘ACZM’ is for. Qualifying to take the exam requires years of clinical experience and publications. That’s followed by a challenging exam—in my case, I specialized in aquatics for my second day of exams, while day one had everything from red-eyed tree frogs to rhinos.”
DiplECZM: “I was also able to get certified with the European College of Zoological Medicine—the ‘ECZM’ in the title—and become a ‘diplomate’ of that group.”

Benefitting animal wellbeing beyond the Aquarium's walls

Members of the Aquarium’s veterinary, water quality and animal care teams share their expertise with the larger community in many ways—for instance, serving in leadership roles with the Association of Zoos and Aquariums (a nonprofit, independent organization that accredits zoos and aquariums, including the Seattle Aquarium, worldwide); helping to rescue and rehabilitate stranded animals; participating in research on wild populations; making presentations; collaborating on and authoring papers and articles—and even co-authoring an entire textbook on fish medicine.

That’s right: On top of her regular duties, Dr. Caitlin Hadfield found time to co-author the 624-page Clinical Guide to Fish Medicine. Written for vets, vet techs, biologists and fish enthusiasts, it’s now required reading for zoological board exams.

What kind of exams are those? “Just like your dentist and knee surgeon have done additional exams to confirm their specialization, there are boards for vets who specialize in zoological medicine or specific types of animals,” Dr. Hadfield explains. “Boards require a lot of extra studying and difficult exams. It’s great to be on the required reading list because it ensures a steady stream of readers! But more importantly, it helps set high standards for health care of fish.”

The book was the first of its kind. “There are textbooks that provide practical information on clinical medicine of domestic species—like dogs and cats—that vets can refer to through the day while at work, but that resource just didn’t exist for fish,” notes Dr. Hadfield. “There are good textbooks on fish, but they are focused on specific aspects of fish medicine or particular diseases and aren’t as useful in a busy clinical setting. So we submitted a proposal to the publisher and they accepted.”

A true team effort

For any team to be successful, each member must bring something different and valuable to the table—and that’s definitely the case at the Seattle Aquarium. “I’m really proud of the team’s diverse skills and how we work together and learn from each other,” comments Dr. Hadfield. “We provide care whenever it’s needed: any time of day or night, any day of the year,” she adds, “so we need a team that can be one voice for animal care and wellbeing, and support the wellbeing of the staff and volunteers we work with. That’s a big task given the variety of species in our care.”

And that variety is increasing in a big way with the opening of the Ocean Pavilion this summer. Interested in a behind-the-scenes look at some of the species you’ll find there—and a chance to see Dr. Hadfield and other Seattle Aquarium team members in action? Check out episode six of our Animal Care Stories series. And if you’re curious about what it takes to become an aquarium vet, dive into this great conversation with Dr. Hadfield!

“When they’re hungry, they’ll let you know:” Caring for dogfish

Posted on September 6, 2022February 9, 2024 by Emma Leiser

Senior Aquarist Chris Van Damme gingerly holds one end of a herring when feeding Elliott and the other Pacific spiny dogfish at the Aquarium. Dogfish—who are just as enthusiastic about meals as their furry namesakes—can chomp through their food with astonishing speed and force. As Chris shares in our interview, it’s just one of the many reasons these creatures inspire awe and affection from their caretakers.

Q: What do you find fascinating about dogfish?
A: You wouldn’t know it from their name, but dogfish are sharks. They’re a smaller species of shark, but like all sharks, they’re fast and sleek. They can turn on a dime. They’re immensely strong.

Dogfish are also record-setters. They have among the longest pregnancies of any animal: 22 to 24 months. (Fun fact: Dogfish pups are born ready to hunt!) They reproduce late in life—as late as their mid-30s for females—and they live long lives—80 years or more! They’re also remarkable travelers. One of my colleagues found a dogfish in California that had been tagged in Alaska.

Q: What surprises people when they visit dogfish at the Aquarium?
A: Visitors who hear there are sharks living in the Aquarium’s Underwater Dome sometimes mistake the sturgeon—a prehistoric-looking animal—for dogfish. Dogfish are understated. They can be hard to spot, and you’ve got to be patient.

Q: Where can you spot dogfish in the Underwater Dome?
A: In the mornings, unless it’s time to eat, you’ll often see them sitting on the sand at the bottom. At other times, you’ll see them swimming about midway up in the Dome.

Q: How does the Underwater Dome mirror how dogfish live in Puget Sound?
A: First, the water here comes directly from the Sound. Its temperature and salinity match their natural environment. Also, the Dome is a multi-species habitat just like in the wild. And, like in Puget Sound, there are open sandy bottoms where they can rest.

Q: What do dogfish at the Aquarium eat?
A: They eat a variety of herring, anchovy, clam, squid and shrimp. Their diet here mimics their diet outside the Aquarium, and that’s important to their health.

Q: Do they consider other fish in the Dome as prey?
A: No, we dive and target-feed them by hand every afternoon to minimize the possibility of that happening. (And since they are primarily scavengers, it’s a highly unlikely scenario anyway.) We also do a surface feed, where we drop larger pieces of food to the bottom for them.

Q: What is it like to hand-feed dogfish?
A: They have very sharp teeth, so it’s important to release the fish before they get too close!

Q: How do they eat outside the Aquarium?
A: They often hunt in packs like dogs—that’s why they’re called dogfish—and can eat their way through schools of fish. (Fun fact: Dogfish can hunt in packs of up to 1,000!)

Q: Are local dogfish populations healthy?
A: Thankfully, our local dogfish populations are healthy. In part that’s because we don’t have a targeted fishery here (meaning that we don’t eat them). Atlantic spiny dogfish, by contrast, are eaten in Europe. Our local dogfish populations are also managed by National Oceanic and Atmospheric Administration fisheries and by the Pacific Coast Management Fishery Council, which helps keep populations healthy.

That said, dogfish and all the animals living in our local waters are affected by what goes in our sewers and drains. (Tip: Learn how you can protect ocean health on our Act for the Ocean page.)

Q: What is a good pathway to a career like yours?
A: I studied oceanography at the University of Washington, which is a good field for studying the marine environment as a system. Oceanography combines physical, chemical, biological and geological science. If you’re specifically interested in working with sharks or helping to manage healthy shark populations, you should consider studying marine biology.

Q: As a diver, have you encountered dogfish outside of the Aquarium?
A: I can think of only a handful of times I’ve seen them while diving. Their senses are a lot better than ours. They see and hear us before we know they’re around, and they move fast.

They’re beautiful animals. It’s such a treasure and a treat to find one as a diver. It’s a gift.

Now that you’ve read Chris’s thoughts, check out our dogfish page to learn more about Elliott and the other dogfish at the Aquarium. On your next visit to the Aquarium, look carefully for Elliott in the Underwater Dome!

What is it like to care for a porcupinefish? Our senior aquarist weighs in

Posted on August 16, 2022February 9, 2024 by Emma Leiser

It’s fair to say that Senior Aquarist Alan Tomita knows more about porcupinefish than most people. An expert on tropical fish, he’s worked at the Seattle Aquarium for more than three decades. In this Q&A, Alan shares insights from his years spent caring for porcupinefish.

Q: What’s especially amazing about a porcupinefish?
A: Its superpower is intimidation. It can scare off predators by swallowing air or water to blow itself to double its size or more. Once it does, its spines—which are otherwise tucked away—transform into dangerous spikes.

Q: Does being puffed up change the way a porcupinefish moves or swims?
A: When a porcupinefish fully puffs itself up, its buoyancy is altered, often causing it to flip upside-down. But the upside-down fish ball has no problem bobbing along. Researchers and caregivers have noticed that a porcupinefish will sometimes puff up for no known reason, and not to the point where it loses buoyancy. This is believed to be the fish’s way of stretching its “puffer” muscles.

Q: In the wild, what kinds of predators are willing to take on a porcupinefish?
A: Because of its clever emerging spikes, the porcupinefish has few enemies. Its main predators are sharks, or fish that are large enough to swallow it whole.

Q: So large fish can safely swallow a porcupinefish?
A: Yes—if the predator can deflate it with its teeth, is big and fast enough to swallow it before it inflates, or is big enough to swallow it whole, even inflated.

However, a porcupinefish has a secret weapon hidden in its organs―a lethal toxin 1,200 times stronger than cyanide. This toxin doesn’t bother all fish and is most dangerous to mammals, including humans. In Japan, where porcupinefish (called fugu in that country) are considered a delicacy, fugu handlers must undergo special training to ensure the fish can be safely eaten.

Q: Are large fish the only threat to a porcupinefish?
A: No, its biggest threats are caused by humans. Since a porcupinefish will bite at whatever it finds floating in the water, it’s at risk for consuming plastic, which is dangerous to its health. People also like to collect porcupinefish, dry out the fish’s skin and inflate it for use as a Christmas tree ornament or lamp.

Q: Where do porcupinefish make their homes in the wild?
A: The porcupinefish—like many types of pufferfish—lives mainly in tropical waters around the world.

Q: What’s an average day in the life of a porcupinefish in the wild compared to at the Aquarium?
A: Porcupinefish living at the Aquarium spend most of their time hanging out, bobbing around and enjoying their own company.

In the wild, this solitary species will mostly sleep during the day and spend nighttime looking for food. It will “hang out” in caves and under ledges, swimming around mostly alone. Only juveniles seek the comfort of other porcupinefish.

A porcupinefish can live peacefully among nearly any type of fish. It’s not often threatened and therefore doesn’t need to use its defense mechanism unless something big comes along to scare it. Kōkala—the featured porcupinefish living at the Aquarium—currently lives in a habitat with about 200 other fish, and everything is simpatico.

Q: What does Kōkala eat at the Aquarium versus what she would eat in the wild?
A: In the wild, a porcupinefish enjoys a diet of hard-shell crustaceans, sea urchins, snails and other invertebrates.

At the Aquarium, Kōkala eats a diet mainly of clams, shrimp and squid, along with a jelly made of vegetable matter.

Q: Does she like her veggie gel?
A: Not really, but it’s good for her, and I can usually get her to eat one small square before she realizes what she’s gulped down.

Q: Isn’t that like a parent trying to sneak veggies into their child’s meal?
A: Exactly!

Q: What practical knowledge have you gained while working with porcupinefish?
A: When I’m caring for Kōkala, “care” is the key word. It’s not just the spikes that make being around a porcupinefish risky; her beak-like teeth also require me to proceed with caution. The first rule is to keep my fingers clear of her mouth. I’m always aware of how easy it would be to lose a finger.

Q: What led you to your career at the Seattle Aquarium?
A: I grew up in Hawai‘i, and my degree is in zoology from the University of Hawai‘i. I’d always wanted to work for a reputable aquarium and had my eye on Seattle for a while. When a position opened, I jumped on it, which turned out to be a smart move because I’ve been here for 33 years now!

Even though Kōkala is a loner, she doesn’t mind visitors! Plan a visit to the Seattle Aquarium, and maybe you’ll be lucky enough to see Kōkala stretch her muscles and puff herself up. You might even catch a glimpse of Alan caring for his favorite fish! Look for the puffers in our care in our Pacific Coral Reef and Tropical Pacific habitats. You can also discover more cool facts about these amazing animals on our pufferfish and porcupinefish webpage.

Four policies to help salmon in Washington

Posted on January 26, 2022February 9, 2024 by Emma Leiser

Each year, thousands of Washington salmon migrate, swimming against the current to return to the rivers and streams where they were born. If you visit the Cedar River in the fall, you may spot bright-red sockeye flashing underwater, Chinook building a redd or coho migrating farther upstream to spawn. Adult salmon die within a few weeks after spawning, and the salmon life cycle begins again with the eggs left behind. Right now, young salmon may be emerging from the gravel, foraging for food and making their home in the Cedar River, where they will live and grow before heading out to sea.

Salmon are keystone species and critical for Washington ecosystems, economies and communities, as well as for the survival of the endangered southern resident orcas. Yet our salmon populations face many threats, and some species are dangerously close to extinction.

Salmon rely on a healthy habitat during all phases of their life cycle, including freshwater, estuarine and marine ecosystems. How can we recover salmon populations and protect their habitat? The Seattle Aquarium is working to advance several actions during the 2022 state legislative session that would support critical ecosystems and healthy salmon and orca populations for years to come. Learn more about these priorities and how you can take action below!

Marine Shoreline Habitat (SB 5885)

The time after juvenile salmon leave streams and rivers behind and enter the Salish Sea is a critical survival period. But along Puget Sound shorelines, structures like old docks and bulkheads that are either unpermitted or have fallen into disrepair disrupt and pollute that nearshore habitat. This bill would require shoreline surveys to map these types of structures, then enable steps to restore nearshore habitat.

Duckabush River Estuary Restoration Project

Estuaries—tidal wetland environments where rivers meet salt water—are important environments for all sorts of species, from migratory birds to juvenile salmon. A $50.2 million state investment in the Duckabush River Estuary Restoration Project would restore critical habitat that fish rely on, including threatened summer chum and Chinook salmon. With estuary restoration, there will be pools and slow water areas for fish to hide, rest and grow until they are ready for the marine environment.

Kelp Forests and Eelgrass Meadows (HB 1661/SB 5619)

Washington state is a global hotspot for kelp diversity and is home to eelgrass meadows that provide nursery habitat for juvenile salmon and feeder fish. Unfortunately, these habitats have declined dramatically. This bill would enable creation of a plan to restore or conserve 10,000 acres of kelp forests and eelgrass meadows by 2040—supporting vital habitat for all kinds of species in our coastal waters.

Lorraine Loomis Act for Salmon Recovery (HB 1838/SB 5727)

Named in honor of late Northwest Indian Fisheries Commission chair and Swinomish Tribe member Lorraine Loomis, this bill would protect and restore riparian habitat along Washington state rivers and streams. Shading these waterways keeps the water cool and clean, making salmon populations and the broader ecosystem more climate resilient as air and water temperatures rise. Stay tuned for updates on this bill as the legislative session advances.

Join us in taking action for salmon!

There are steps you can take right now to help salmon have a better chance of recovery:

If you live in Washington state, speak up this week for salmon. Email your elected officials or call the toll-free legislative hotline at (800) 562-6000 (TTY for hearing impaired (800) 833-6388) between 8am and 7pm, Monday through Friday, to leave a message for all three of your legislators at once. Ask them to support HB 1838/SB 5727, SB 5885, HB 1661/SB 5619 and a $50.2 million investment in the Duckabush estuary project.
Discover other ways to help salmon and protect ocean health.

Read about our other 2022 legislative priorities and sign up for our email action alerts.

Duckabush Estuary: An important opportunity for recovery

Posted on December 16, 2021February 9, 2024 by Emma Leiser

In discussions about conservation, certain habitats tend to come up as particularly important to restore and protect. Coral reefs and mangroves often immediately come to mind but feel far away from us here in the Pacific Northwest. However, there are critical aquatic habitats found right here in Puget Sound, including estuaries! Estuaries are tidal wetland environments where rivers meet salt water; these junctions are important environments for all sorts of species, from migratory birds to juvenile salmon. We now have a chance to restore a key estuary in Washington: the Duckabush River estuary.

Critical habitat

Juvenile salmon spend months in estuaries undergoing a process called smoltification, when they grow and develop a tolerance for salt water. This is a rare superpower—few aquatic species can survive in both salt and fresh water—and the estuarine habitat, at the junction between river and ocean, is needed for salmon to adapt!

Unfortunately, development has eliminated or degraded 75% of river delta tidal wetlands in Puget Sound. This enormous loss is especially problematic for juvenile salmon and other fish and wildlife that rely on estuaries. Many of those species are listed as threatened under the Endangered Species Act.

Salmon are keystone species, meaning their loss would reverberate throughout their ecosystems. Predators of salmon, such as orcas, birds, bears and people, are directly impacted by declining salmon runs, while other species are impacted in less direct ways. When salmon die after spawning or while traveling up rivers, for example, their bodies provide nutrients to trees and other plants along the riverbed. These trees then provide shade and keep the water cool enough for salmon eggs to survive and provide safe habitat for young salmon as they journey down the river. Trees also sequester carbon and provide habitat for many other animals. This intricate ecosystem interdependency is beautiful, but it’s at risk due to human impacts.

Duckabush Estuary Restoration Project

The Duckabush River estuary is located on the western shore of Hood Canal. Highway 101 runs right over it, giving drivers access to the Olympic Peninsula. When this segment of the highway was designed in 1931, 12 feet of fill was used to support the new roadbed. Most of us probably aren’t thinking about what’s under the road we drive on, so long as it’s flat and stable. Unfortunately, all the fill, dikes and road infrastructure block water channels and limit critical habitat that fish rely on, including threatened Hood Canal summer chum and mid-Hood Canal Chinook salmon. Water bottlenecks created by the current highway also cause seasonal flooding.

The Washington Department of Fish and Wildlife (WDFW), in partnership with the U.S. Army Corps of Engineers and the Hood Canal Salmon Enhancement Group, has proposed a project to elevate the highway and restore the estuary so that it is once again prime habitat for fish and other species. There is a unique opportunity for a federal-state partnership to share the cost of this project: $50 million in state funding would unlock $30 million in federal funding. Check out this video from WDFW to learn more about what’s being planned.

For this important project to move forward, we need Washington legislators to secure funding in this state legislative session.

Join us in taking action!

Updated February 2023: If you live in Washington state, please call or email your state legislator and ask them to support a $41 million state investment in the Duckabush River Estuary Restoration Project during the 2023 state legislative session! Email your elected officials or call the toll-free legislative hotline at 1-800-562-6000 (TTY for hearing impaired 800-833-6388) between 8am and 7pm, Monday through Friday, to leave a message for all three of your legislators at once. This is an opportunity to make a real difference for threatened salmon and a vital ecosystem.

Specialist surgeon visits Aquarium to help a red Irish lord

Posted on July 6, 2021May 9, 2024 by Emma Leiser

An egg-bound red Irish lord (Hemilepidotus hemilepidotus) at the Seattle Aquarium needed surgery, so a board-certified surgeon from Animal Surgical and Orthopedic Clinic (ASOC) performed the necessary procedure. Senior Veterinarian Dr. Caitlin Hadfield and Curator of Fish & Invertebrates Tim Carpenter here at the Aquarium explain more:

Q: What can you tell us about this species?

Tim: Red Irish lords are part of the sculpin family. They tend to rest on the bottom of shallow waters, down to depths of 1,500 feet. They’re common from the Bering Sea, near Alaska, to Washington, and are rarer south to central California. These fish are highly camouflaged and often overlooked by divers. Given that this species is not a common commercial or recreational fishing target, complete biological data on the species is not well-published. Based on limited fishing and other data gathered by the state of Washington, they can grow up to 20 inches long and 2.45 pounds in weight. Their maximum age is at least 6 years old.

Q: What does it mean for a fish to be egg bound?

Tim: Egg binding occurs when a female produces eggs but is not able to release them. This can lead to a buildup of eggs with each successive “clutch”, and the eggs become increasingly abnormal over time. There are many possible causes; we’re not sure why this species gets egg bound.

Q: Why was a board-certified surgeon needed to assist on a surgery for this red Irish lord fish’s case?

Dr. Hadfield: Aquarium and zoo veterinarians frequently reach out to specialists when we think it’s in an animal’s best interest. In this case, the anatomy is the main reason.

In fish like koi and salmon, the ovaries are two separate structures that sit loosely within a thin membrane and are easy to remove if they cause issues. In Irish lords, the two ovaries combine at the back, making them U-shaped, and that caudal aspect (i.e., near the tail) is tightly adhered to the body wall and the colon. Combined with that, these abnormal ovaries are very large—about 50% of the fish’s body weight—and the ovarian wall holding in all the little eggs is fragile.

These factors make this a particularly difficult surgery. We had tried environmental changes and hormones to induce egg laying but without success, and this surgery was needed to save the fish’s life. Dr. Alex Aguila, a board-certified surgeon from ASOC, and his surgical assistant, Sarah Gagliano, have extensive experience with difficult surgeries.

Alex was able to remove all the ovarian tissue, which is great news. The surgery is challenging and it is common to have to leave some of the ovarian tissue; this can regrow and cause more issues later on. Dr Aguila was also fast! This meant we were able to reduce the total anesthetic time to about 90 minutes, which also helps improve the long-term prognosis for the fish. And this was also a great opportunity for us all to work together and learn. The Seattle Aquarium has worked with ASOC for over 30 years, and we look forward to continuing our strong relationship well into the future.

Q: How does surgery happen on a fish?

Dr. Hadfield: To anesthetize a fish like this, we use a drug that is dissolved in the water. We keep that medicated water flowing over the fish’s gills through the surgery using a pump that moves the water through a big loop while we monitor the condition of the water. This lets us keep the fish’s belly out of water for the surgery. We also provide pain relief, similar to what you or your pet would receive, including anti-inflammatories, opioids, and local anesthesia around the surgery site. Once the fish is pre-medicated and on our surgical system, the surgeon can drape the site and get started. While there are differences in anatomy (like a lack of fur!), how surgery is done is similar to dogs and cats, including using the same types of sutures (stitches) to close up the body wall and skin.

Q: What happens next for the care of this red Irish lord?

Dr. Hadfield: The surgery was about a month ago, and the fish is doing great. She is eating again and looking like a healthy red Irish lord. She will get some more recheck exams and then move back to the Window on Washington Waters habitat. She has a small transponder now (just like your dog or cat), so we will be able to monitor her over time to see how she does.

Q: What are other examples of when specialists visit the Aquarium to help the animals in our care?

Dr. Hadfield: We are lucky enough to have a large support network of specialists in the zoo and aquarium field as well as in the private sector, including anesthesiologists, cardiologists, radiologists, ophthalmologists, and oncologists (lots of -ologists, really!). These specialists routinely donate their time and expertise to help improve the health and welfare of the animals under our care. One of the things that I appreciate most about this field is that we all want to learn and help each other out.

Q: When has the Aquarium shared our expertise in the community or with peer institutions and other organizations or efforts?

Dr. Hadfield: This is a hugely collaborative field, and we each try to help where we can. People often reach out to us to discuss challenges they may be having with species that we have under our care, as well as programs that we are particularly well known for, such as our animal welfare assessments and conservation programs.

You can come check out our Tropical Pacific habitat and try to find a red Irish lord during your next visit to the Aquarium. Be sure to book your ticket in advance; we look forward to seeing you!

Climate resilience in coral reef fish communities

Posted on June 9, 2021February 9, 2024 by Emma Leiser

Fish assemblage structure before and after a marine heatwave in West Hawaiʻi

Guest blogger Amy Olsen began her time at the Seattle Aquarium as a volunteer diver in the Underwater Dome habitat. She is now a laboratory specialist/research technician in the Conservation Programs and Partnerships department. Her Master in Marine Affairs program is in the School of Marine and Environmental Affairs at the University of Washington.

Coral reefs are subject to marine heatwaves caused by human-induced climate change. Long-term thermal stress can negatively affect corals and the associated marine organisms that use these areas as critical habitat by causing coral bleaching. Coral reefs provide important ecosystem goods and services such as fisheries and tourism as well as aesthetic and cultural value. Healthy coral reefs have been estimated to add $477 million annually to Hawaiʻi’s economy through tourism and subsistence, recreational and commercial fisheries (Cesar & van Beukering, 2004).

For my master’s thesis project, I examined coral reef resilience to climate change by analyzing changes in fish assemblages (i.e., which species exist in the same area at the same time) after a marine heatwave. I analyzed 11 years of subtidal video survey data in three areas in West Hawaiʻi, capturing a marine heatwave event from 2014 to 2016. Fish were counted and identified to species, then assigned to one of seven functional groups: predators, secondary consumers, planktivores, corallivores and three herbivore groups—scrapers, grazers and browsers.

The dataset I used was collected by my supervisor, Dr. Shawn Larson, curator of conservation research at the Seattle Aquarium. This work falls under climate resilience, one of our three organization-wide conservation priorities along with sustainable seas and clean waters.

The Seattle Aquarium has been conducting video-based reef monitoring surveys every year in Hawaiʻi since 2009. The goals of this monitoring project are the following:

Document changes in fish diversity and abundance over time.
Determine coral cover (how much of the ocean bottom is covered by coral versus rock or sand), identify coral species and calculate percentage of coral bleaching over time.
Collect environmental data such as bacteria, nutrients and microplastics.

I used statistical tests to evaluate how the fish communities changed after the marine heatwave. All three areas in West Hawaiʻi were found to be different in the years after the heatwave. Interestingly, regardless of how differently these areas are managed or how different the habitat is, all three communities became more similar to each other.

This has been previously described in the literature where climate changes in the marine environment favor small, generalist, algae-eating fish that are able to adapt to these changes. This is called biotic homogenization and has been cited as a pressing global biodiversity crisis (Dornelas et al., 2014, Magurran et al., 2015, McGill et al., 2015).

Kona, the Marine Life Conservation District with the highest level of fishing protection among our sites, showed the highest total fish abundance and least variation over time in abundance over the study period, suggesting ecosystem stability. These sites had the highest diversity values and also documented the highest coral loss. While the fish assemblage was significantly different after the marine heatwave, the observation that fish abundance remained high could indicate this area has higher resilience than the other two areas, and may suggest more stability to new or unusual environmental conditions (Bernhardt & Leslie 2013).

Marine protected areas can be an effective management strategy to prevent overfishing, protect diverse species and provide a refuge for life stages that are more sensitive, but they do not prevent warming of the ocean surface or coral bleaching. However, management policies that prevent overfishing of herbivorous fish, such as browsers or scrapers, can prevent phase shifts from healthy coral reef systems to algal-dominated systems which has been found to aid reef resilience (Hughes et al., 2003).

Protected reefs lead to higher abundance and biodiversity of reef fish (McLean et al., 2019). Coral and fish species responses to thermal stress is highly variable, so networks of marine protected areas require thoughtful place-based approaches for effective implementation. Success is dependent on an effective combination of science-based management, public support and political will (Bellwood et al., 2004).

Understanding how marine heatwaves impact coral reef communities can guide decision-making for effective coastal management. Continued long-term monitoring is necessary to evaluate disturbance impacts on the coral reef ecosystem, as we anticipate climate change and marine heatwaves will continue into the future.

Take action!

To help protect coral reefs from these stressors, the Seattle Aquarium is supporting policies such as the Restoring Resilient Reefs Act (S.46 and H.R.160). This act would provide new federal grants to support state coral reef management and restoration and respond to coral reef emergencies and disasters. You can help! Visit this Aquarium Conservation Partnership quick action page to encourage your members of Congress to co-sponsor this bipartisan legislation.

References:

Bellwood DR, Hughes TP, Folke C, Nyström M (2004) Confronting the coral reef crisis. Nature 429:827–833.

Cesar HSJ, van Beukering PJH (2004) Economic valuation of the coral reefs of Hawaiʻi. Pacific Sci 58:231–242.

Dornelas M, Gotelli NJ, McGill B, Shimadzu H, Moyes F, Sievers C, Magurran AE (2014) Assemblage time series reveal biodiversity change but not systematic loss. Science (80- ) 344:296–299.

Hughes T, Jackson J, Kleypas J, Lough J, Marshall P, Palumbi S, Pandolfi J, Rosen B, Roughgarden J (2003) Climate Change, Human Impacts, and the Resilience of Coral Reefs. Science (80- ) 301:929–933.

Magurran AE, Dornelas M, Moyes F, Gotelli NJ, McGill B (2015) Rapid biotic homogenization of marine fish assemblages. Nat Commun 6:2–6.

McGill BJ, Dornelas M, Gotelli NJ, Magurran AE (2015) Fifteen forms of biodiversity trend in the anthropocene. Trends Ecol Evol 30:104–113.

McLean M, Auber A, Graham NAJ, Houk P, Villéger S, Violle C, Thuiller W, Wilson SK, Mouillot D (2019) Trait structure and redundancy determine sensitivity to disturbance in marine fish communities. Glob Chang Biol 25:3424–3437.

Protect Bristol Bay

Posted on July 31, 2020December 19, 2023 by Emma Leiser

Last Friday, the U.S. Army Corps of Engineers cleared the way for permitting a huge mine at the headwaters of two major rivers that feed into Bristol Bay, Alaska—home to the world’s largest sockeye salmon fishery and one of the most prolific Chinook salmon runs.

The Canadian-owned Pebble Limited Partnership (“Pebble”) would extract gold, copper and molybdenum—materials of extremely high value, found in everyday items such as seatbelts, cell phones and electrical wires—through a new open pit mine.

The Seattle Aquarium strongly opposes the Bristol Bay Pebble Mine. Healthy oceans, fishing and Indigenous communities and local economies depend on wild and clean rivers and waterways. These will all be harmed if the Pebble Mine is developed. The science clearly shows the dangers posed by developing the mine are too great to allow the project to proceed. And yet, the Trump Administration is determined to do so, as it continues its relentless efforts to roll back environmental projections—from the National Environmental Policy Act to the Endangered Species Act—and ignores the call for environmental justice.

In the final environmental impact statement released last week, the Corps concluded that the mine “would not be expected to have a measurable effect on fish numbers” or “result in long-term changes to the health of the commercial fisheries.”

The science does not back up that finding. Mining in these rivers would cause both environmental and economic damage. The EPA’s earlier scientific assessment found that the mining activities would destroy more than 80 miles of streams and 3,500 acres of wetlands and generate billions of gallons of mine pollution. The surrounding marine ecosystem, $1.5 billion-dollar fishing industry, and over 14,000 jobs—including jobs held by fishermen from Washington state—that depend on these fish would be put in jeopardy.

We stand with Alaska Natives, fishing communities and others who have been opposing this mine for years. The salmon runs in Bristol Bay are essential to the health of the surrounding ecosystems and sustainable economies. We call on the EPA to follow the best available science and the principles of environmental justice and invoke a veto under Section 404(c) of the Clean Water Act.

If you’d like to take action, consider contacting your elected official and asking them to speak out against the Pebble Mine. Here in Washington, Senator Cantwell and Representative Kilmer have already done so—so please thank them if you are their constituent! You can also post your concerns on social media and tag @EPA and @USACEHQ.

Recovering Northwest salmon

Posted on April 7, 2020February 9, 2024 by Emma Leiser

We simply can’t have a week of online engagement about Puget Sound fish without devoting some very special attention to one of the most culturally significant and iconic local species, critical to the overall health of our Pacific Northwest marine and terrestrial ecosystems: the salmon.

Many people know that the broad term “salmon” encompasses several different species. Seven of those are found here in the Pacific Northwest: Chinook (also known as king), coho, chum, pink, sockeye, steelhead and cutthroat. And, within our Pacific salmon and Pacific trout species in Washington state are a whopping 486 distinct populations—each one a scientifically designated, biologically distinct group of individuals (e.g., Snake River spring/summer Chinook; Skagit River coho) adapted to specific streams, estuaries and other conditions.

When people join us for the Cedar River Salmon Journey each October to see salmon spawn, they’re witnessing the journey of a specific group of salmon, through specific conditions that only the Cedar River provides. Because of varying conditions from river to river and from the river mouth to the headwaters, each salmon population has slightly different timing for their reproduction: when they’re in the open ocean and signaled to return, when they start to move upriver, and when their eggs hatch.

Salmon start their lives as juveniles in local streams, rivers and estuaries before heading out to the open ocean. Depending on their species and population, salmon may spend anywhere from six months to five years in the ocean. Some travel thousands of miles during this time. Environmental factors like the availability of food, water temperature, river flows (which influence dissolved oxygen), ocean acidification and pollution all play a role in long-term health of all salmon species.

An additional challenge facing salmon is the destruction of their traditional spawning grounds through man-made structures, deforestation, climate change and habitat encroachment.

Policy action on behalf of salmon

One of the important conversations taking place around local salmon recovery is the improved operation or even removal of man-made structures, like dams, on salmon-bearing rivers. The Aquarium continues to advocate for science-based policies that can help conserve our marine environment, and recently took a position supporting the removal of the four lower Snake River dams to help recover and restore critically endangered salmon populations.

Salmon recovery and the lower Snake River dams

The Columbia River basin once saw 10 to 16 million salmon return to spawn, with the Snake River—the Columbia’s largest tributary—welcoming over 4 million returning salmon¹. But the cumulative impacts of habitat loss, climate change impacts on ocean temperatures, and the construction of 14 federal dams throughout the basin have nearly decimated these fish populations.

According to the 2017 ESA Recovery Plan, by the early 1990s, “abundance of naturally produced Snake River spring/summer-run Chinook salmon had dropped to a small fraction of historical levels.” Many salmon populations in the Columbia/Snake basin have already gone extinct, and nearly all remaining ones are listed as either endangered or threatened under the Endangered Species Act (ESA).

Unlike other dams in the basin, the four lower Snake River dams are not necessary for flood protection. In part for that reason, they have been the focus of discussions about potential dam breaching (removing the earthen embankments and putting other infrastructure out of commission) for more than two decades, with an eye to supporting salmon recovery. The science is clear: breaching the dams would significantly increase spring/summer Chinook returns. It would improve the chance of recovery for endangered Columbia and Snake River Chinook, sockeye and steelhead. It would also require both authorization and significant funding from Congress.

The connection to the orcas

Removing the four lower Snake River dams, as part of a broad suite of measures, could also improve salmon availability in the long term for the endangered southern resident orcas. These orcas spend part of the year off the coast, looking for food, and the science indicates that they rely on Chinook returning to the Columbia River in the spring.

For the orcas to recover, additional measures must also take place in the immediate to near term, including restoring and protecting salmon habitat in other places around the region, reducing vessel noise and disturbance, and reducing toxic runoff.

The draft environmental impact statement

In February, the agencies that operate the 14 dams released a draft environmental impact statement (DEIS). They found that breaching the four lower Snake River dams would result in the greatest benefits to endangered salmon. They did not select that as the preferred path forward for system operations, however, citing the loss of power generation at the dams, among other factors.

Seattle Aquarium position

We are deeply concerned about the declines in wild, endangered Chinook, sockeye and steelhead populations. The science points to breaching of the Lower Snake River dams as a way to improve the chance of recovery for salmon and steelhead populations in the Columbia River basin.

Broader local and regional conversations are needed to arrive at solutions in the basin that will work for both salmon and communities. We look to our governor and legislators to help continue these important conversations, and we thank the governor for the stakeholder engagement work that is already underway.

Opportunity to comment

The Seattle Aquarium will be submitting a comment letter on the DEIS. If you’d like to weigh in on the DEIS as well, you can submit a comment in the agencies’ online form by the April 13 deadline.

¹NMFS 2008 Recovery Plan for Southern Resident Killer Whales (Orcinus orca) at II-82