Food web

Puget Sound hosts more than 100 species of seabirds, 200 species of fish, 15 marine mammal species, hundreds of plant species, and thousands of invertebrate species. These species do not exist in isolation, but rather interact with each other in a variety of ways: they eat and are eaten by each other; they serve as vectors of disease or toxins; they are parasitic; and they compete with each other for food, habitat, and other resources.

--Source: Sound Science 2007 

Bear eats salmon. Photo: Robert Voors (CC BY-NC-ND 2.0) https://www.flickr.com/photos/robert_voors/1303192433

OVERVIEW

Food webs

The health of an ecosystem is tied closely to the health of its food webs. This article provides an overview of the concept, origin, and characteristics of a food web and how predator and prey relationships are shaped in the Salish Sea.  

RELATED ARTICLES

A harbor seal skull in a box
9/8/2020

History of food web found in harbor seal skulls

Tiny bone samples show that seals alter their diets as conditions change. The findings could help scientists understand whether seals are contributing to local salmon declines.

A harbor porpoise surfing in a boat wake in Burrows Pass, off Fidalgo Island, WA. Photo: Copyright Cindy R. Elliser, Pacific Mammal Research http://pacmam.org/
10/22/2018

Harbor porpoises become increasing players in the Puget Sound food web

With a population growth of about 10 percent per year in inland waters, harbor porpoises are having an undetermined but growing effect on food dynamics in Puget Sound.

Dead salmon. Photo: Boris Mann (CC BY-NC 2.0) https://www.flickr.com/photos/boris/3037705761
7/14/2017

The nearshore food web: Detritus

Detritus, or dying or decaying matter, is a central component of the nearshore food web in Puget Sound. This article was prepared as part of the Puget Sound Fact Book produced by the University of Washington Puget Sound Institute. 

Storm surges against the bulkheads protecting beach houses at Mutiny Bay, WA. Photo: Scott Smithson (CC BY-NC-ND 2.0) https://www.flickr.com/photos/dtwpuck/15725058917
3/22/2016

Shoreline armoring's effect on the food web

The removal of shoreline armoring in Puget Sound has become a priority for state and federal agencies, but until recently there have been relatively few scientific studies of armoring's local impact. New research looks at the pronounced biological and ecological effects of these common shoreline structures, especially for tiny beach-dwelling creatures that make up the base of the food web.

Early morning meal. Photo: jdegenhardt (CC BY-NC-ND 2.0) https://www.flickr.com/photos/jdegenhardt/2771107305
2/24/2016

Food web connections beyond the marine areas of Puget Sound

Food webs are natural interconnections of food chains and depict what-eats-what in an ecological community. While Puget Sound represents a specific food web, the organisms that reside within that web often travel outside the region. In this way, one community's food web can be drastically affected by a change in a neighboring ecosystem.

Pathogen-free herring are reared from eggs to allow a wide range of experiments on infectious organisms at the Marrowstone Marine Field Station. Photo: Christopher Dunagan
1/13/2016

Disease in herring threatens broader food web

Pacific herring have long been considered an essential part of the Puget Sound food web. Now, studies are beginning to reveal how diseases in herring could be reverberating through the ecosystem, affecting creatures large and small. We continue our coverage of the ecological impacts of disease in Puget Sound with this look at the region's most well-known forage fish.

Great blue heron fishing. Photo: Leo Shaw, The Seattle Aquarium.
2/16/2012

Food Web

Puget Sound hosts more than 100 species of seabirds, 200 species of fish, 15 marine mammal species, hundreds of plant species, and thousands of invertebrate species. These species do not exist in isolation, but rather interact with each other in a variety of ways: they eat and are eaten by each other; they serve as vectors of disease or toxins; they are parasitic; and they compete with each other for food, habitat, and other resources.

A stream full of hundreds of swimming salmon.
11/21/2023

Surging numbers of pink salmon raise ecological concerns

An estimated 70% of all the salmon in the North Pacific are pink salmon. Scientists say the extreme abundance of pinks could be causing a "trophic cascade" that is harming species across the food web.

Underwater view of shark and several smaller yellow and white fish swimming in coral reef.
6/25/2023

Quantitative models, including Ecopath, take food web studies to a higher level of analysis

The Ecopath model, designed to describe the flow of energy through a food web, as evolved since it was first developed in the early 1980s in Hawaii. This article is part of a series focused on different models and their uses within the Puget Sound ecosystem.

A purple sea star attached to a rock covered with mussels and seaweed.
3/31/2023

Oxygen for life: How low dissolved oxygen affects species in Puget Sound

Scientists are reporting a decline in oxygen-rich waters throughout the world. Causes for the decline vary from place to place but may involve climate change and increasing discharges of tainted water. In Puget Sound, low oxygen levels can occur naturally or due to eutrophication from human-caused pollution. In this five-part series, we describe the critical nature of oxygen to Puget Sound sea life. Scientists are finding that changes in oxygen levels can lead to physiological adjustments, shifts in predator-prey relationships and other repercussions throughout the food web.

Rhinoceros auklet carrying sand lance. Photo by Peter Hodum.
3/15/2023

Resilience to a severe marine heat wave at two Pacific seabird colonies (author summary)

A 2023 paper in the journal Marine Ecology Progress Series examines seabird reproductive and dietary response to a severe marine heat wave affecting the California Current ecosystem from 2014 to 2016. The study involved rhinoceros auklet colonies on Destruction Island (California Current) and Protection Island (Salish Sea). The paper's first author Eric Wagner describes some of the findings from the study in this informal summary.

Neotrypaea californiensis, the bay ghost shrimp. Image courtesy of Dave Cowles (wallawalla.edu)
10/25/2022

Eyes Under Puget Sound: Critter of the Month - Ghost Shrimp

Fall’s chill is in the air (finally!), leaves are turning colors, and skeletons and spider webs are popping up in yards all over town. Meanwhile, under the mud of Puget Sound, there’s a strange critter that stays in its ethereal costume all year long – the burrowing ghost shrimp.

Two people lift a basket of rocks from a stream flowing through a forest.
10/21/2021

Can 'bug seeding' improve the health of local creeks?

Bug seeding involves moving beneficial insects and other aquatic invertebrates from healthy streams to streams where these creatures are missing from the food web.

Researchers in a boat near killer whales
5/10/2021

Southern residents’ winter diet comes into focus

A 2021 paper in the journal PLoS ONE provides a clearer picture of what endangered southern resident orcas eat throughout the year. Chinook salmon make up the bulk of the whales' diet, but the paper suggests that other salmon species and non-salmonid fishes can also play important roles depending on the season.

A woman standing on a rock in a river holding a long pole with a net on the end. Photo: Rachael Mallon
12/15/2020

Once hearty 'hooligans' declining in the Salish Sea

A river spawning species of forage fish known as the longfin smelt is rare and getting rarer in the Salish Sea. Biologists are looking into the mysterious decline of the ‘hooligans’ of the Nooksack.

Volunteer Vernon Brisley surveys a bull kelp bed near Ebey’s Landing on Whidbey Island as part of the Island County MRC regional monitoring project. Photo: Rich Yukubousky
11/21/2019

Kelp crisis? Decline of underwater forests raises alarms

They rival tropical forests in their richness and diversity, but Puget Sound's kelp beds have declined steeply in recent decades. Scientists are just starting to understand the extent of these losses. What they are finding is bringing kelp to the forefront of Puget Sound's environmental concerns.

Eyes Over Puget Sound report cover
8/7/2019

Eyes Over Puget Sound: Surface Conditions Report - July 29, 2019

In July, the recent trends of warm, dry conditions lessened; however, river flows remain low. Extensive macroalgae drifted through South and Central Sound and washed up on beaches. Macroalgae growth is fueled by excessive nutrients and sunshine. When it washes onto the beach, it is called beach wrack, and it can be a health risk to beachgoers because of bacteria it can harbor. From our aerial photography, we saw that Southern Hood Canal looks tropical because of a bloom of coccolithophores coloring the water turquoise. Schools of fish congregate in South Sound and southern Hood Canal. Jellyfish are abundant in Quartermaster Harbor.

Clouds of herring milt in the water seen during spawning season near Brinnon, WA on Hood Canal, March 2019. Photo: copyright John Gussman, with permission http://www.dcproductions.com
4/11/2019

The herring defenders

Each winter and spring, researchers survey the sometimes spectacular spawning events of Puget Sound's Pacific herring. They have found wide swings in the fish's population and an overall decline in herring numbers since the 1970s, but little is known about the cause or what this might mean for the health of the food web. We spent a day with a biologist spotting herring eggs and considering the future of one of our region's most ecologically and culturally important fish species. 

Pacific herring (Clupea pallasii). Image courtesy of NOAA.
9/24/2018

Pacific herring distribution in Puget Sound

Pacific herring are a pelagic fish species found from northern Baja California to northern Honshu Island, Japan. They are found throughout the Puget Sound basin and are a mix of “resident” and “migratory” stocks. 

A milky, turquoise, phytoplankton bloom in Hood Canal visible from space. Natural color MODIS image from Landsat 8 acquired July 24, 2016. Photo: NASA Earth Observatory https://earthobservatory.nasa.gov/NaturalHazards/view.php?id=88454
3/6/2018

Does Puget Sound need a diet? Concerns grow over nutrients

As the region's population grows, scientists say we can expect to see increasing amounts of nitrogen and other elements flowing into Puget Sound. Known as “nutrients” these elements are naturally occurring and even necessary for life, but officials worry that nutrients from wastewater and other human sources are tipping the balance. That could mean big problems for fish and other marine life, gradually depleting the water of oxygen and altering the food web.

The rapid growth of a red-orange algae, Noctiluca scintillans, dramatically colors the waters of Puget Sound near Edmonds on May 16, 2013. Such algae blooms have been seen more frequently in recent years. Photo: Jeri Cusimano via WA Ecology (CC BY-NC 2.0) https://www.flickr.com/photos/ecologywa/8744775119
2/28/2018

Dead plankton leave clues to a food-web mystery

High amounts of elements such as nitrogen can cause blooms of phytoplankton that sometimes trigger perturbations throughout the food web. This occurs most often in the spring and summer after the long, dark, cloudy days of winter begin to fade.

Harbor Seals sunning on intertidal rocks of Puget Sound. Photo: Tony Cyphert (CC BY-NC-ND 2.0) https://www.flickr.com/photos/tony717/14630242564
1/17/2018

Study would explore changes to protections for seals and sea lions

As wildlife managers work to recover Puget Sound’s diminished Chinook population, a proposed white paper is expected to review the impacts of some of the salmon's chief predators. The study would include a section on potential management of seals and sea lions, prompting open discussion of a long taboo subject: Could officials seek to revise the Marine Mammal Protection Act — or even conduct lethal or non-lethal removal of seals and sea lions in some cases? Such actions are hypothetical, but we look at some of the ongoing discussions around the issue as prompted by a new resolution from the Puget Sound Leadership Council. 

A young resident killer whale chases a chinook salmon in the Salish Sea near San Juan Island, WA. Sept 2017. Photo: (CC BY-SA 2.0) https://flic.kr/p/21wV8rV
11/20/2017

Seals and sea lions may be slowing salmon recovery, hurting orcas

Increased consumption of Chinook salmon by seals and sea lions in the Salish Sea “could be masking the success of coastwide salmon recovery efforts,” according to a new study published in the journal Scientific Reports. Endangered resident orcas are said to be declining in part due to a lack of available Chinook, the orcas' preferred prey.

WDFW biologists sorting and measuring fish from PSEMP's index sites in the Duwamish River and near the Seattle Waterfront. Photo: WDFW
8/25/2017

Monitoring helps to reveal hidden dangers in the food web

Toxic chemicals have been showing up in Puget Sound fish for more than a century, but consistent testing over the past 30 years has helped to reveal some unusual patterns of pollution.

Sea lion sunbathing between meals in Seattle's Eliott Bay. Photo: Johnny Mumbles (CC BY 2.0) https://www.flickr.com/photos/mumbles/3283168713
1/25/2017

Study says predators may play major role in chinook salmon declines

A new study shows that increased populations of seals and sea lions are eating far more of Puget Sound’s threatened chinook than previously known, potentially hampering recovery efforts for both salmon and endangered killer whales. 

Toxic algal blooms are sometimes associated with invasive plankton. Photo: Eutrophication&Hypoxia (CC BY 2.0) https://www.flickr.com/photos/48722974@N07/5120831456
10/4/2016

Salish Sea snapshots: Invasive species and human health

Invasive species are considered a top threat to the balance of ecosystems worldwide. New discoveries of non-native green crabs in Puget Sound have highlighted that concern here at home, but invasive species can impact more than just the food web. Some introduced species can produce toxins that accumulate in shellfish or by directly infecting the human body.

Rhinoceros Auklet carrying sand lance. Photo by Peter Hodum.
9/20/2016

Salish Sea snapshots: Plastics in fish may also affect seabirds

Sand lance in parts of British Columbia are ingesting small pieces of plastic that may be passed through the food web.

Chinook salmon (Oncorhynchus tshawytscha). Photo: WDFW
6/17/2016

Contaminants higher in resident 'blackmouth' Chinook

Many of Puget Sound's Chinook salmon spend their entire lives in local waters and don't migrate to the open ocean. These fish tend to collect more contaminants in their bodies because of the sound's relatively high levels of pollution. 

Studies suggest that western sandpipers depend on biofilm for close to 60% of their diet. Storey's Beach, Port Hardy, BC. Photo:  Nicole Beaulac (CC BY-NC-ND 2.0) https://www.flickr.com/photos/nicolebeaulac/26579296150
6/1/2016

Salish Sea 'slime' vital for shorebirds

It turns out that a gooey substance known as biofilm is a big deal for Salish Sea shorebirds, providing critical food for some species. But could a proposed port expansion in Vancouver threaten this slimy resource?

Puget Sound's orcas are among the most contaminated marine mammals in the world. Photo: Minette Layne (CC-BY-2.0) https://en.wikipedia.org/wiki/Killer_whale#/media/File:Orca_porpoising.jpg
5/18/2016

New theory rethinks spread of PCBs and other toxics in Puget Sound

Researchers are proposing a shift in thinking about how some of the region’s most damaging pollutants enter Puget Sound species like herring, salmon and orcas.

Pacific herring (Clupea pallasii). Image courtesy of NOAA.
9/14/2012

Forage fish in Puget Sound

Forage fish occupy every marine and estuarine nearshore habitat in Washington, and much of the intertidal and shallow subtidal areas of the Puget Sound Basin are used by these species for spawning habitat.