May 21st is World Fish Migration day! It is a one-day global initiative to educate people about the importance of global fish migrations. The first ever World Fish Migration Day (WFMD) was held in 2014 and was largely successful. This year, we continue to reach out to the public to share the marvel of fish migrations and demonstrate the value of this behavior. As an ecologist studying a fish migration, I think they are a big deal. But humans have been taking advantage of these annual migrations since the dawn of civilization.
The Types of Migration
There are two main modes of annual fish migrations: fish that migrate from the ocean to freshwater, and fish that migrate from freshwater to the ocean. The general term that applies to all fish that migrate through rivers to spawn is diadromous fishes (to be clear, many species of fish migrate on a regular basis from one area of ocean to another. However, these migrations are not the focus of WFMD or this post because these migrations are not profoundly impacted by humans the way fish that migrate from oceans to rivers and vice versa are).
Most diadromous fish would fall into the category of anadromous, or fish that spend most of their adult life in the ocean, but come into freshwater to spawn. Salmon are the most famous example of anadromous fish with herring, striped bass, and sturgeon joining their ranks. The flip side of this strategy is catadromous fish which spend the majority of their life in freshwater but migrate into the ocean to spawn. Eels are the primary example of catadromous fish. Thanks to their highly predictable natural spawning migrations, anadromous fish like salmon or herring leave the large ocean where they are very difficult to catch and come right to our backyard in highly concentrated numbers. Because anadromous fish have proven extremely easy to catch relative to many other fish species, they have been a staple to human diets for centuries.
The Peril of Migratory Fish
It should come as no surprise that any fish that was harvested literally by the boat-load (Figure 1) eventually had population problems. The problem of overfishing is all-too-familiar for so many fish species. But migratory fish in particular have another major issue to be concerned about – dams. Any obstacles built on the river, such as a large dam, prevents the fish from reaching their spawning grounds upstream and ultimately from reproducing (Figure 2). The combination of harvesting adults and preventing reproduction is a recipe for disaster that has resulted in severely depleted stocks of most diadromous fishes around the world.
Fig, 1 Fishermen unloading salmon from a lighter, Nushagak, Alaska, 1917. University of Washington Libraries, Special Collections, Cobb 4148, http://www.bristolbaysockeye.org/historic-photos/
Fig, 2 An example of a fish ladder – engineers’ attempt to allow diadromous fish to pass dams – on the Columbia river. Photo by USACE, Public Domain.
The Role of Migratory Fish
These migratory fish species are more than a convenient (and admittedly delicious) meal. They serve an incredibly important ecological role. After rain storms, soil, leaves, and many other bits of matter and nutrients wash into streams and rivers and are subsequently swept out to sea. Therefore, there is constant delivery of material and nutrients to the ocean. Anadromous fish are one of the only mechanisms to return energy and nutrients back to freshwater and terrestrial systems. After spending years feeding in the ocean, anadromous fish carry all those ocean-based nutrients accumulated in their tissues with them into rivers where bears, eagles, osprey, raccoons, otters, turtles, and so much more can receive energy inputs from the ocean.
What You Can Do
Interested in participating in WFMD? There’s a few things you can do. You’ve already done the first step by reading this post! Next, feel free share this post with others to spread the word about WFMD. Then, go to the World Fish Migration Day website or their Facebook page to learn more about the mission and what is being done. You can search for local events that may be taking place near you using this interactive map. If you are in Western Massachusetts, but not near one of the sponsored events listed on the site, consider visiting the Holyoke Dam fish lift which has a public viewing window to watch anadromous fish continue their journey past the dam (Figure 3). Or, if you live near a river that has a herring run, you may be able to volunteer to assist in estimations of river herring population trends by conducting visual counts. The most important thing you can do is help to educate yourself and others about the value of these species and our impacts on them.
Fig. 3 Salmon passing the viewing window at Ballard/Chittenden locks fishway in Seattle, WA (similar to the Holyoke Dam viewing window). Photo by Joe Mabel, Wikipedia commons.
Herring volunteer count opportunities
Video count option
More From Thats Life [Science]
- When You Call a Fish a Frog
- Who’s Got the Biggest Genome of Them All?
- The Biology of Booze ft. Tequila
- Dying Tomatoes, Healthy Kittens, and the EMP500: Why you should care about the International Society for Microbial Ecology
- The Purebred Poodle Problem
- Let It Glow
- I’m Likin’ That Lichen
- Celebrate the Holidays with a Decorative Parasite
- Sleeping One Hemisphere at a Time
- Through the Mycologist's Hand Lens: Deceptive Decomposers
- Life Science in Outer Space!
- 5 Things You Didn’t Know About Rats
- Watermelon Snow
- Critter Candid Cam
- Three Cool Plants in Hot Places
- A parasite only a moth could love
- Telling tales of plants and their names
- The Colorful World of Primate Hair
- Where do fish go in winter?
- You Scratch My Back and I’ll Scratch Yours
- Alien Microbes: How studying hyperthermophiles can help us discover life on other planets
- Life, the universe, and everything: Dreams of being a biophysicist
- Bug Sleuth – One Entomologist’s Mission to ID a Mysterious Swarm of Wasps
- Horny and Hungry: The Dilemma of Sexual Cannibalism
- Who’s who? The elusive difference between butterflies and moths
- Tuberculosis - A Romantic Disease?
- Ode to a Few Arachnids
- Monotropa uniflora - This wildflower is pretty wild
- Eavesdropping in the Animal Kingdom: Sneaky Creatures Just Trying to Get Ahead
- Trypanosomes - A Weird Pathogen You Haven't Heard Of
- A Beautiful 9/11 Tribute, but a Fiasco for Migratory Birds
- Cats can have AIDS, too.
- Part 2: Does catching Pidgeys help you notice Pigeons? Interviews with Pokémon Go Researchers
- Biodiversity in my Backyard: Encounters with Pidgeys and Dratinis, Part 1
- Fins, Limbs, Rays, and Digits – A Beginner’s Guide to Terrestrial Living
- Fins, Limbs, Rays, and Digits – A Beginner's Guide to Terrestrial Living
- Five things that really stink about the Brown Marmorated Stink Bug
- Tricks but no Treats - An Orchid’s Guide to Making a Fool of Your Pollinator
- Tracking the lost years - where do baby sea turtles grow?
- Posing as a Bird Mama: the adventures of a researcher-turned-bird-parent
- Hot moves and sexy sons · When Boys Become Men By Dancing
- The hungry caterpillar in real life
- Mantis Shrimp Vision - Seeing in Secret Code
- When It Comes to Bird Beaks - Size Matters
- Is your gut trying to kill your resolve? · Mind over microbe
- Recent talk of walls in the media has brought up a lot of emotions, but what do walls do in nature? · When a Wall is just a Wall
- Bees are more than buzzing insects around you · May the Bees Be With You: Maintaining the Sweet Balance in Life
- Neither a toad nor a worm · Nematodes: The super microscopic animal!
- Snap! Flash! Bang! Find out how ocean-dwelling pistol shrimp fire bubble ‘bullets’ to stun their unsuspecting prey. · How Pistol Shrimp Kill with Bubbles
- Who needs males after all?
- Ecology and Behavior of Woodchucks · Opposition Research on My Garden’s Greatest Nemesis
- Vision in Jumping Spiders · Watching Your Every Move
- Slimed and Consumed - The Blob is Real!
- The Evolution and Ecological Impacts of Cats · Lion in Sheep's Clothing
- What happens when frogs have to compete for acoustic space and a chance to be heard? · Struggling to be Heard - Competition in a Complex Soundscape
- Think Genghis Khan and Napoleon were the most successful invaders? Think again. · Invasive Species and Invasion: Part 1
- When, and how, terror birds invade
- 8 Reasons Plants Are Amazing
- Too Clean for Comfort · How our obsession with cleanliness might be hurting our health
- Stop, evaluate, and listen - serotonin surges when a female is present
- No Teeth, Long Tongue, No Problem - Adaptations for Ant-eating
- The Good, the Bad, and the Ugly - Predators, Parasitoids, and Parasites
- How our microbiome affects our health and vice versa · If you don't care for your microbiome, you might want to start
- Finding new ways to grow bacteria to progress science · Culturing the Least Cultured Members of Society
- Hit the Road Jack
- What Happened to Your Nose?
- Building better plants - Norman Borlaug and the Green Revolution
- Love Songs for Nobody - Birdsong in Winter
- We know we get infections from time to time. Why does this happen? · The Evolution of Virulence
- How cheese rinds may be a valuable tool for microbial discovery · The Unseen World – On Cheese?
- Find Me Where the Wild Things Are
- A commentary on how to make science more ‘clickable’ · You won’t believe this simple trick to tell if your coral is healthy or not
- Some species hide in plain sight, but scientists have ways to suss them out · Cryptic Species Hide in Plain Sight
- Minuscule Hitchhikers Pinch a Ride · Creature Feature - Pseudoscorpions
- World Fish Migration Day 2016!
- Walking With Giant Anteaters
- Why we should care about sea turtles · When A Sea Turtle Balanced Earth
- More ›