This blog is the first in a new series “Little Giants” exploring the importance of forage fish and the marine ecosystems they inhabit around the world.

Why Forage Fish Depend on Salish Sea Kelp Forests

Most people wouldn’t give “forage fish” a second thought.  These fish are small, silvery, and often not very impressive looking, swimming around the open ocean in giant schools feasting on microscopic plants and algae. Although it may seem a bit fishy, these little fish play a big role in marine ecosystems around the world.   

The truth is that forage fish are a vital part of the marine ecosystem serving as a source of food for many people and animals. Also called prey fish, forage fish transfer nutrients and energy up the food chain to predators like salmon, whales, seals, and seabirds. They are also an indicator of overall ecosystem health – when their populations dwindle, it’s a sign that something bigger may be happening.

The Salish Sea, in the Northeast Pacific Ocean, is one of the places where forage fish thrive. The Salish Sea is loosely defined as the inland sea that spans Washington State in the United States, and British Columbia in Canada — encompassing Puget Sound, Hood Canal, the Strait of Juan de Fuca, and the Strait of Georgia. Three important forage fish species – Pacific herring, surf smelt, and Pacific sand lance – call this special place home and provide valuable ecosystem services.

Pacific herring © Shutterstock/Ulovetrin Pacific sand lance © Shutterstock/BGP Mobile Surf smelt © Shutterstock/Alex Coan Why Do Forage Fish Inhabit Kelp Forests?

 These amazing little fish require a special underwater sanctuary, and that is exactly what the Salish Sea’s nearshore kelp forests provide. Known as the “forests of the sea,” kelp consists of brown algae species that form dense, towering canopies, which provide critical habitat for many marine species and important ecosystem services. Kelp are truly a powerhouse: they cycle key nutrients, draw down and store carbon in their fronds, protect coastlines from erosion and storm surges, and even combat ocean acidification.

For Pacific herring, the most common forage fish in the Salish Sea, kelp forests are particularly important for reproduction. The herring deposit their eggs on nearshore vegetation including kelp, creating a spawning spectacle so large it draws spectators to see the “fields of snow” formed by the massive amount of herring eggs amongst the waves.  

Aside from spawning, kelp forests play a vital part in the life cycle of all three Salish Sea forage fish species.  Pacific herring, surf smelt, and Pacific sand lance all rely on kelp forests to find food as these areas have a higher abundance of zooplankton than areas with no kelp.  

What Are the Top Threats to Forage Fish in the Salish Sea?

Nine million people live in the Salish Sea region. Like in many other coastal communities, human activity, such as shoreline armoring (i.e. bulkheads), and impacts on water quality and temperature have altered the coastline, destroying kelp forest habitat that forage fish rely on for spawning, shelter, and food.

 The Samish Indian Nation estimates a 36% decline of bull kelp forests, the primary Salish Sea kelp species, around the San Juan Islands in Washington State between 2006 and 2016.  

Rising water temperatures, coastal development, and diseases like sea star wasting syndrome all contribute to kelp loss and will continue to threaten kelp ecosystems that Salish Sea forage fish rely on.

How Can We Protect Forage Fish in the Salish Sea?

Protecting forage fish means protecting the kelp habitats they rely on. Luckily, researchers, advocates, and policymakers already understand the importance of kelp habitat in the Salish Sea.  In 2025, Washington State lawmakers designated bull kelp as the state’s official underwater marine forest.  Though these designations are largely symbolic, they give coastal communities a way to unite behind the importance of kelp to the region. 

Kelp recovery is an emerging strategy, and scientists are examining many pathways including cultivation and seed banking that may one day allow for more widespread ecosystem recovery.

Additionally, state agencies, Tribal Nations, and nonprofits are working together to understand the dramatic decline of kelp in the Salish Sea, and what can be done about it.  Organizations like the Vashon Nature Center are conducting kayak and snorkel surveys to observe changes in kelp forests and the animals living among them.  

 Saving these underwater forests won’t happen overnight, and it will take more than a single solution. It’s going to take innovation and a collective refusal to let this wild ecosystem slip away. The small but mighty forage fish of the Salish Sea are doing their part under the water. It’s time for us to do ours on the surface.  

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