Puget Sound Foodweb

Objective: Students will learn about different organisms that live in Puget Sound. They will work together to assemble a food web, compare their designs, and then use their models to explore interactions in the ecosystem. Teacher Preparation: Download and print copies of this PDF. It is designed to be printed two-sided in color (or in B&W) on 8 ½ X 11 paper. Print one copy of the food web cards for every 2-3 students.

Time Needed: 50 minutes (30 minutes food web, 20 minutes for gallery walk/discussion)

Materials Needed: For every 2-3 students (1 set of Food web Cards, 1 larger sheet of paper, 2 pairs of scissors, 1 glue stick, 3-4 colored markers).

Introduction/Instructions: Divide students into pairs or threes and spread them out around the classroom. Tell students that they will be learning more about steelhead and other animals that live in Puget Sound. Each group will work independently to build a food web diagram that represents interactions in the ecosystem and then will share their work with their classmates.

Food Web Activity:Hand out a worksheet to each group. Ask students to cut their worksheet into food web cards and then start arranging the cards into food chains/webs on their desk. The back of the cards provide information to help them make connections between different organisms. Give students about 10 minutes to look through all of the cards and start making connections. You may want to have them pause at this point to review some relevant vocabulary words (ie. predator, prey, producer, consumer, decomposer, carnivore, herbivore, photosynthesis.) Once they think they have their cards organized, give each group a sheet of larger paper and a glue stick to start pasting their cards onto their poster. As a last step, students can personalize their webs by drawing in other connections or arrows, categories/groups (predators, sea birds), and other elements that are important for their web (the Sun for energy!) There is no perfect answer as it depends on how the students explain their work. Even scientists are always learning about new connections and relationships in the ecosystem.

Follow-Up Gallery Walk and Discussion:Have each group hang their food web diagram up on the wall. Give students a couple minutes to walk around the room looking at all the different webs and have them jot down 1-2 questions or observations about the different webs that they see. What is the same/different? What do you notice? What do you like about another group’s web? Come back together as a group and ask students to share a few of their thoughts with the whole group.

1. Why did some groups put a sun at the top when others put a human at the top? 2. Do the drawn in lines/connections look the same for everyone?3. Did you focus on the predator- prey relationships or the transfer of energy through the

web? Does this change what your web looks like? (Note: Younger kids tend to focus on who eats who and older students (middle school and up) will start switching over to focusing on transfer of energy through the food web which is more how scientists usually look at these interactions.

4. Ask students to use their Food Web model to answer a couple questions about ecosystem interactions.

5. Since we’ve been learning about steelhead, what is one animal in your web that would directly impact the amount of steelhead in the ecosystem? Indirectly?

6. Name two animals that compete for the same food source. What happens if the amount of prey increases or decreases? What if the number of one of the predators increased?

7. Conclusion: Ecosystems are complicated places with lots of different species and many varying interactions. When we try to study one organism, like a Steelhead, we have to look at a lot of different animals and investigate many different factors (predator- prey interactions, fluctuating population size, human impacts.) Scientists use complicated models on the computer to investigate food web and ecosystem interactions. (See sample images below. You may want to project these so students can see samples.)

Puget Sound Foodweb

phytoplankton zooplankton

jellyfishpacific oysters

crabs

market squid

spiny dogfish

salmon harbor seals

harbor porpoises humans

cormorants

forage fish

Puget Sound Foodweb

insects

steelhead

eelgrass

Southern Resident killer whales

Bigg’s transient killer whales

gadids & greenlings

bald eagles

Crab species are important prey for many fishes (including salmon) & birds. Larval (baby) crab eat phytoplankton & zooplankton. Adult crabs live on the seafloor & eat small crustaceans, clams, & fish. Spiny dogfish prey on adult crabs, & crabs also sometimes prey on other crabs. Humans love to eat many crabs especially Dungeness crab.

Market Squid is a carnivore that primarily eats zooplankton (krill, copepods) & small fish like herring. Squid are also cannibalistic; they will eat other squid. Squid use tentacles to catch their prey & a parrot-like beak to tear food into pieces. Birds, harbor seals, gadids, & humans like to eat squid.

Forage fish are small, silvery fishes that are eaten by almost everything. They are generally high-lipid prey, & are often some of the most ecologically important species in marine ecosystems. Puget Sound forage fishes include Pacific herring, northern anchovy, Pacific sand lance, & surf smelt. They eat zooplankton, including copepods, crab larvae, & krill. They are important prey for salmon, birds, & harbor seals.

Gadids (hake, cod, pollock) & green-lings (lingcod) are recreationally important. They eat a variety of prey, including zooplankton, forage fishes, squid, rockfish, sculpins, & some salmon. Adults can also cannibalize juveniles. Lingcod are one of the top predators in Puget Sound: they can get very large (> 1 m) & live for up to 20 years. Harbor seals, birds, & spiny dogfish prey upon these fish.

Cormorants can dive below the surface to catch food or look for fish, insects, or crustaceans in shallow water. Their hooked bill is a tool for hanging onto prey. They mostly feed on fishes, like surfperch, forage fishes & juvenile steelhead. They have few predators but may die accidentally by getting tangled in fishing gear.

Spiny dogfish are small (< 1.5 m), long-lived (up to 75 years) sharks that are common here. They eat a diverse diet including herring, gadids, ratfish, flatfish, octopuses, crabs, & salmon. During World War II, millions of spiny dogfish were harvested for their vitamin A rich livers. They are popular recreational & commercial food fish for humans & are also eaten by harbor seals, birds, & lingcod.

Bald Eagles are large, carnivo-rous birds that capture prey with their large talons. Their distinc-tive white heads are iconic. They build the largest nests of any bird in the world. They eat fish, other birds (like cormorants & ducks), & land mammals. They feed heavily on salmon carcasses after the salmon have spawned. Bald eagles have no predators but they may die accidentally from human activities like hunting or fishing.

Steelhead spend a year/two in rivers, eating insects, before they travel out to the ocean & eat zooplankton, small invertebrates, & other fish. They move offshore once they hit saltwater & travel great distances across the ocean; the longest of any salmon. They feed near the water’s surface, so are at high risk of consuming floating marine plastics. Many die on their way to the ocean; they are eaten by predators (harbor seals).

Harbor Seals are the most common pinnipeds in Puget Sound. They live here year-round & often stay near a favorite haul-out site (a rocky area, dock or other surface near the water). Harbor seals primarily feed on fish, like gadids, forage fish, salmon & squid. They are eaten by Biggs transient killer whales, may also die as a result of human activities like fishing or hunting.

Bigg’s (Transient) Killer Whales are toothed whales that reside in the North Pacific Ocean. They are fierce predators who sometimes hunt in packs. They are seen in Salish Sea waters in the fall & have increasingly been observed in Puget Sound. They don’t have predators & primarily eat marine mammals, but also eat birds, squid, sharks, & other whales.

Humans love to eat seafood. Some of their favorites are shellfish (clams, mussels, crab, oysters) & fin fish (herring, salmon, cod), but they also eat seaweed, sea salt, & fish eggs. Humans do not have any predators that live in the ocean.

Salmon are ecologically, eco-nomically, & culturally significant in Puget Sound. Many populations have declined & are struggling to survive. Salmon feed on terrestrial & aquatic insects, amphipods, & other crustaceans when they are young. As they grow older, they consume marine zooplankton (like larval crab & krill) & forage fish. Salmon are an important food source for killer whales, harbor seals, & humans.

Phytoplankton, like land plants, have chlorophyll & need sunlight to live & grow. Phytoplankton are highly productive in Puget Sound because of its unique patterns of tides, rivers, & winds. They bloom in spring, summer, & fall, & provide food for a wide range of organisms including whales, shrimp, snails, zooplankton & jellyfish.

Insects are invertebrates. They are part of the base of the food web. They feed on plants & bacteria & are eaten by many species of fishes & birds in rivers & estuarine environments. Aquatic or terrestrial insects that are transported into Puget Sound waters provide an important high-energy food source for juvenile salmon & other pelagic fishes.

Zooplankton is made up of many species of animals (mostly small crustaceans like copepods, amphipods, crab, shrimp, & krill). Some are larval (baby) forms of marine animals & others spend their whole lives as free-floating organisms. Many feed on each other & become the base for an entire food web, from the smallest fish to the largest whale. Most fish, birds & jellyfish eat zooplankton.

Pacific Oysters filter plankton from the water, straining up to 60 gallons of water a day. They depend on their very thick shells to ward off attacks by crabs or birds who want to eat them. Humans also love to eat oysters; oyster farming is an important industry in the Pacific Northwest.

Jellyfish are not fish; they are invertebrates. They thrive in warm, nutrient-rich waters & can tolerate low-oxygen environments. Jellyfish congregate into “blooms,” or “smacks,” of many individuals & can consume large amounts of phytoplankton & zooplankton. Few animals eat these soft, gelatinous creatures, so they are sometimes considered a “dead-end” in the food web.

Harbor Porpoises are common in some areas of the Salish Sea & their abundance may be increasing in Puget Sound. They are the smallest cetacean recorded in Puget Sound waters at < 2 m & < 100 kg. Observers rarely see more than their small dorsal fins, as they do not often leap from the water. Harbor porpoises primarily eat fishes & squids. They are eaten by Biggs transient killer whales.

Southern Resident Killer Whales are toothed whales that reside off the coast of the NW area of the US & Canada. The Southern Resident killer whale population is so small that they are listed as endangered. One important factor inhibiting their recovery is a lack of their favorite prey; the endangered Chinook salmon. Sometimes they feed on steelhead & chum salmon.

Eelgrass is not a seaweed; it is a blooming underwater grass which spreads by rhizomes or roots. Diatoms & bacteria gather on the leaves, providing food for many grazing invertebrates & birds. Its roots stabilize sediment & its leaves shelter small fishes like juvenile salmon. Eelgrass is also important spawning habitat; herring in Puget Sound lay their eggs on its leaves.

Puget Sound Foodweb