Forage Fish like Anchovies and Sardines are Vital to the Health of Marine Ecosystems
Updated: Sep 23, 2019
Understanding the major significance of these fish and why they need more attention
Oceans are extremely complex ecosystems that provide habitat and resources for millions of plants and animals. There is a delicate balance that needs to be maintained or the entire system will begin to fall apart. Forage fish are one of the most important elements for keeping this balance in order.
Forage fish have been defined as, “any fish or invertebrate species that contributes significantly to the diets of other fish, birds, mammals, or sea turtles, or otherwise contributes disproportionately to ecosystem function and resilience due to its role as prey.” Some of the primary species commonly considered to be forage fish are anchovies, sardines, herring, menhaden, krill, and small squid. These small fish swim throughout the oceans in large schools and are a vital source of food for a wide variety of animals.
Maintaining a healthy abundance of these tiny fish is critical to ensure our oceans remain productive for generations. Some regulations have been set by state and federal agencies to manage a few of these species, but some groups are concerned forage fish aren’t getting proper attention. Organizations like Oceana, Pew Charitable Trusts, and Audubon Society are calling on the regulatory agencies to take a more comprehensive science-based approach to assessing stock sizes that takes the whole ecosystem into account.
Forage species feed upon nutrient-rich plankton before becoming prey themselves. They are essentially the foundation for the entire marine food web. Marine mammals like dolphins, whales, and seals feed almost exclusively on forage fish. Larger fish like tuna and salmon also rely heavily on these tiny fish for their primary source of food. And seabirds like gulls, terns, cormorants, and pelicans regularly prey upon forage species as well.
According to a report from Oceana on marine forage species, there are 19 marine mammal species, 33 seabird species, and over 40 species of larger fish that need forage fish to survive. Some of those predator species are endangered or threatened. The report illustrates that there is a direct link between the availability of forage species and the health of the predatory species. Declines of animals like salmon, marine mammals, and some birds have been observed as a result of insufficient amounts of forage fish. They also highlighted that since 2003 there has been a 75% drop in predatory fish populations in the California Current which may be linked to a lack of forage fish.
A study published in the scientific journal Fish and Fisheries analyzed the ecological and economic value of forage fish. The study explains how there has been a growing consensus within scientific communities that there should be a more ecosystem-based approach when considering management policies for fisheries. Currently, most forage fish are monitored and regulated by what is known as single-species management. This approach leaves out many of the ecosystem factors like water temperature that can dramatically affect forage fish numbers.
Importance for Birds
Forage fish clearly serve as an important food source for the fish and marine mammals that live in the ocean, but they are also essential for many bird species. Gulls, terns, pelicans, cormorants, and many other seabirds rely on forage species for their survival.
Megan Flaherty, Restoration Program Manager for the San Diego Audubon Society, says seabirds are excellent bioindicator species. She says, “Seabirds are the perfect kind of canary in the coal mine for ocean ecosystem health.” She explains that through monitoring seabirds it can become apparent whether or not there is a healthy amount of forage fish. “[O]nce seabird populations start to decline, or if they're breeding and productivity goes down, or if they start having mass die off events, that kind of implies that there's something going on with the food that they rely on,” says Flaherty.
The California Least Tern is an endangered species that nests along the sandy shorelines of Southern California every year. They are especially dependent on a steady supply of forage fish, not only for themselves, but for their chicks as well. “[A]nchovy really is the perfect fish to feed to their chicks for two reasons - one, they're thin bodied, so it's easy for the chicks to swallow them - two, they're really high in fat. So, [they] can fatten up a chick really quickly with really healthy and very nutritionally dense food for the chicks,” says Flaherty.
A study was conducted from 1994 to 2012 that looked at Brandt’s Cormorants and their breeding success relative to the availability of forage fish. The study shows that anchovies turned out to be a critical factor in how successful the cormorants were during their breeding season. An abundance of anchovies appears to contribute significantly to a strong population of Brandt’s Cormorants.
A similar study was conducted to monitor the diets of three different species of puffins in the North Pacific. Monitoring the overall health of Tufted Puffins, Horned Puffins, and Rhinoceros Auklets helped researchers better understand the stability of the marine ecosystem.
Flaherty and Audubon San Diego have joined with other groups like Sea and Sage Audubon, Audubon California, Pew Charitable Trusts, and Oceana to advocate for more ecosystem-based management practices. She recently went with fellow Audubon staff members and several volunteers to speak before the Pacific Fisheries Management Council and push for these more comprehensive methods of assessing fish populations.
Forage fish benefit so much more than just the oceans and marine wildlife. Commercially, these little fish are used as a food source for humans, and they are found in pet food, livestock feed, fertilizers, cosmetics, and health supplements.
A report released by the Lenfest Forage Fish Task Force determined the total economic value of forage species is roughly $17 billion to global fisheries. That breaks down to about $6 billion from direct forage species fisheries and around $11 billion in contribution to other commercial fisheries.
Dr. Tim Essington, Director for the University of Washington’s Center for Quantitative Science, sits on the technical advisory board for the Marine Stewardship Council and was part of the Lenfest Forage Fish Task Force. He says, “The task force was convened to basically give guidance to fisheries management around the world on best practices to apply for managing forage fish, largely because of their import ecological role and their importance to fisheries, and basically to sort of balance those two needs.”
He says it can be difficult to establish precise numbers to go off when trying to manage these species. For example, forage fish can go through major population swings. “They have these big booms and busts. They'll be super abundant for a while and then they'll be really scarce for a while,” says Essington. “So, that's already hard to try to come up with good harvest rules to kind of deal with them. And then it's doubly hard when you're trying to think about how you plan to make sure that there's enough food for the other valued species in the ecosystem,” he adds.
Suzzane Musson works at Dave’s Fuel Dock in Ventura Harbor and sells live bait for the local fishing community. Sardines and anchovies are the primary bait fish offered. She also owns a commercial fishing boat and recognizes just how important it is to have fresh live bait in order to successfully catch fish and make a living. “[T]he quality is really important as well, because if you've got bait that's not healthy and it’s lost all its scales it's not going to entice other fish,” she says.
Musson believes there is need for some regulation but cautions how it can adversely impact the industry. “If they were to close [sardine fishing] down and not let them catch sardines it would be a really big fiasco. I mean lots of people out of work, lots of money. That would be a mess,” she says.
Travis Mitchell of Channel Islands Sportfishing sees value in regulation as long as it’s calculated comprehensively. He says, “If we don't really have an idea of how much [fish] there are, or how fast they might be diminishing, then it would be hard to say.” He understands the idea behind an ecosystem-based management strategy of analyzing population swings and environmental fluctuations before setting limits.
Using forage species like sardines and anchovies are important for the sportfishing business. Steve Arroyo, who also works for Channel Islands Sportfishing, agrees the solution comes from looking at the entire ecosystem. “They’d be looking at things like climate change, and what’s causing the tuna depletion. And then they look at other fish and if they’re collapsing due to overfishing, or because we harvest all the bait fish and they can’t eat, or is it a mixture of both,” says Arroyo. “Let's look at the problem as a whole, let's find the root of the problem,” he adds.
Aquaculture, which is the farming of fish for consumption, has been a rapidly growing industry over the past several years because of the increasing demand for healthy seafood. Aquafarms use forage fish to feed their stock. And so, as the demand for farm-raised fish increases, more forage fish are needed to sustain the industry. One study explains how the aquaculture industry will likely have to search for an alternative to forage fish that is equally nutritional for their stock to remain sustainable.
One major commercial use for forage fish that has also seen a steady increase in demand is fish oil supplements. The component of fish oil that makes it appealing is the omega-3 fatty acids it contains. These omega-3 fatty acids have been suggested to potentially reduce heart disease and inflammation, slow the effects of aging, and aid brain function.
Anchovies are one of the primary forage species used in the production of omega-3 fish oil supplements. But it turns out these fish actually form these healthy omega-3s by consuming algae and plankton that produce it naturally. There are even vegetarian options for omega-3 supplements which may have the same level of health benefits without needing to harvest fish to produce.
Paul Greenberg, author of "American Catch" and "The Omega Principle," has given presentations and has written extensively on this subject, encouraging a more sustainable approach to food production and the pursuit of health. He believes we can obtain these essential omega-3 fats from sources like mussels and kelp that can be raised in a more environmentally responsible way than how food is currently grown. Not only does production of these nutritious plants and animals produce less carbon, they also help clean and purify the ocean, which would benefit the entire ecosystem.
It’s a Big Ocean
Even though the oceans are vast and filled with life, they are sensitive ecosystems that require balance. Forage fish are a key element to these systems, and if they are not managed properly the planet will suffer, wildlife will struggle to survive, economies will falter, and human health will decline. It is critical that scientists, researchers, politicians, and management agencies join together and come up with comprehensive sustainable solutions to ensuring these tiny fish gain more attention.
One recent step that appears to be in the right direction is the bill introduced to congress earlier this year known as the Forage Fish Conservation Act (H.R.2236) which aims to create better management practices dealing with forge species. The bill is making its way through the appropriate committees right now before moving on to a vote. Hopefully, this will be the first of many steps in the process of ensuring there is a bounty of these critical little fish for generations to come.
Take Action Now
Please visit organizations like Oceana, SeaLegacy, Pew Charitable Trusts, Blue Sphere Media, and Audubon Society to learn more about the issues facing our oceans and how you might be able to help. Staying informed and educating others is the best way to make progress. The oceans need your help.