Coho salmon and Atlantic salmon are entirely different species from separate evolutionary branches. Coho (Oncorhynchus kisutch) are Pacific salmon native to North America and Asia, while Atlantic salmon (Salmo salar) evolved in the Atlantic Ocean and European rivers. The most important difference for anglers: coho max out around 33 pounds and die after spawning once, while Atlantic salmon can reach 103 pounds and spawn multiple times.
You’ll also find them in completely different waters. Coho run from Alaska to Baja California and across the North Pacific to Japan. Atlantic salmon inhabit cold rivers from Quebec to Connecticut in North America, plus northern Europe, Iceland, and Russia — though wild populations are severely depleted and most fishing today targets landlocked or stocked fish.
Quick Comparison
| Feature | Coho Salmon | Atlantic Salmon |
|---|---|---|
| Scientific Name | Oncorhynchus kisutch | Salmo salar |
| World Record | 33 lb 4 oz (Salmon River, New York) | 79 lb 2 oz (Tana River, Norway) |
| Where to Find Them | Pacific Coast from Alaska to California, Great Lakes tributaries, introduced in some inland waters | Maine rivers, landlocked populations in northern New England and eastern Canada, introduced in Pacific Northwest and Great Lakes |
| Key Identifying Feature | Small black spots only on back and upper tail lobe, lighter gumline in lower jaw | X-shaped spots above lateral line, spots rarely extend below lateral line, jaw extends to rear of eye |
| Fight | Explosive strikes with acrobatic jumps and tail walks, multiple powerful runs | Spectacular aerial displays with sustained deep runs and exceptional stamina |
Physical Identification
Both species flash bright silver in saltwater, but their spotting patterns tell the story. Coho have small black spots concentrated on their backs and the upper lobe of the tail only — the lower tail lobe stays clean. Atlantic salmon display distinctive X-shaped spots above the lateral line that rarely venture below it.
Check the jaw and gumline if you’re still unsure. Coho have noticeably lighter pigment along the gumline of the lower jaw compared to chinook salmon. Atlantic salmon have a relatively small head — about one-fifth of their body length — and the jaw extends back to the rear of the eye but not beyond.
Body Markings and Color
Ocean-phase coho sport dark metallic blue or greenish backs with brilliant silver sides and a light belly. When they enter freshwater to spawn, they transform dramatically — males develop a strongly hooked snout, large teeth, and dark reddish-maroon coloration on the sides.
Atlantic salmon go through even more color changes throughout their life cycle. Juveniles show brown to bronze bodies with dark vertical bars and red and black spots for camouflage. Before migrating to sea, they lose these markings and become silvery with nearly black backs. Spawning adults return bright silver, then darken to bronze before spawning. Post-spawn fish — called black salmon or kelts — darken further before (if they survive) returning to the ocean and regaining their silver sheen.
Size Differences
Atlantic salmon dwarf coho in maximum size. The world record Atlantic salmon weighed 79 pounds from Norway’s Tana River, and the species can reach 103 pounds. Coho top out at 33 pounds — still a substantial fish, but less than half the Atlantic’s potential.
Average sizes differ less dramatically. Most coho you’ll catch run 8-12 pounds, with 20-pounders considered trophies. Atlantic salmon average similar weights in most fisheries, though fish over 20 pounds are more common where conditions allow them to thrive. Atlantic salmon also live longer — up to 13 years versus 5 years max for coho — which contributes to their larger maximum size.
Habitat and Range
Coho salmon inhabit the entire North Pacific rim. In North America, they’re native from Point Hope, Alaska, south to Chamalu Bay in Baja California, Mexico. Across the Pacific, they range from Russia’s Anadyr River south to Hokkaido, Japan. They’ve been successfully introduced to the Great Lakes, where they support major sport fisheries in tributaries throughout Michigan, Wisconsin, and New York.
Atlantic salmon once thrived throughout the North Atlantic in both Europe and North America. Today, wild populations are severely reduced. In the U.S., you’ll find them primarily in Maine rivers. Landlocked populations exist in lakes and rivers across northern New England and eastern Canada. They prefer cold water — 50-60°F in freshwater, 40-50°F in the ocean — and cease feeding entirely above 68°F.
Both species are anadromous where conditions allow, hatching in freshwater before migrating to saltwater to feed and grow. Coho spend about a year in their natal streams, then 1.5 years in the ocean before returning to spawn at ages 3-4. Atlantic salmon may spend 1-3 years in freshwater and 1-3 years at sea before returning. The critical difference: coho die after spawning once, while Atlantic salmon can survive to spawn multiple times.
Fishing Tactics
Coho fishing revolves around aggressive presentations that trigger their predatory instincts. In the ocean, troll with spoons and hoochies behind dodgers or flashers using 20-30 pound mainline. Productive spoons include Krocodiles, Cleos, and Pixees in silver, chartreuse, and pink. When coho enter rivers, switch to 10-15 pound line and drift fish with cured salmon eggs, cast spinners like Vibrax Blue Fox or Panther Martins, or float fish with yarn flies in pink, orange, and cerise.
Atlantic salmon fishing demands a completely different approach — especially in freshwater where they largely stop feeding. Fly fishing dominates, using classic patterns like Blue Charm, Green Highlander, and Undertaker swung across current on 7-9 weight rods with 12-20 pound tippet. You’re triggering territorial aggression or reflexive strikes, not hunger. Single barbless hooks are required in many jurisdictions. In saltwater, Atlantic salmon feed aggressively on herring, capelin, and sand lance, and you can troll spoons or cast plugs with spinning gear.
Coho strike explosively and fight with spectacular aerial displays — tail walks, multiple jumps, and powerful runs that test your drag. They’re exceptionally strong for their size. Use size 1/0 to 3/0 octopus or siwash hooks for bait, and keep your hooks needle-sharp.
Atlantic salmon are even more challenging. They’re selective in freshwater, requiring technical presentations and careful fly selection. When hooked, they deliver explosive runs and spectacular jumps with exceptional stamina. They’re considered one of the most difficult freshwater game fish — not just because of their power, but because of how selective they can be about taking flies.
Regulations and Conservation
Check regulations carefully before targeting either species. Many Atlantic salmon populations are protected, with catch-and-release-only rules or complete closures in areas with wild fish. Coho regulations vary widely by state and province, with some rivers open and others closed to protect specific runs. Great Lakes coho are typically managed for harvest, while Pacific Coast regulations often restrict retention to protect wild stocks while allowing harvest of hatchery fish (marked by clipped adipose fins).
Both species face habitat challenges from dams, warming water temperatures, and degraded spawning grounds. Atlantic salmon are particularly vulnerable due to their depleted populations and complex life history requiring pristine conditions in both freshwater and marine environments.
Frequently Asked Questions
Which is better, coho salmon or Atlantic salmon?
For sport fishing, it depends on where you live and what you’re after. Coho are more accessible to West Coast and Great Lakes anglers, fight aggressively, and are managed for harvest in many areas. Atlantic salmon offer a more technical challenge with spectacular fights, but access to quality fishing is limited due to depleted wild populations. Both are exceptional game fish.
Is coho salmon the healthiest?
Both coho and Atlantic salmon are excellent sources of omega-3 fatty acids and protein. Wild-caught fish of either species provide similar nutritional benefits. The “healthiest” depends more on whether the fish is wild or farmed — wild salmon of both species typically have better omega-3 ratios and fewer contaminants than farmed fish.
Why is coho salmon cheaper?
Coho salmon costs less than Atlantic salmon primarily because Atlantic salmon dominates commercial aquaculture worldwide. Farmed Atlantic salmon production is massive and efficient, driving down retail prices despite the species’ larger size. Most coho sold commercially is wild-caught, which typically commands higher prices, but market demand for Atlantic salmon keeps it premium-priced.
Why avoid Atlantic salmon?
Concerns about Atlantic salmon focus on farmed fish, not the species itself. Farmed Atlantic salmon may contain higher levels of contaminants and have lower omega-3 ratios than wild fish. Environmental issues include farm waste, escaped fish competing with wild populations, and disease transmission. Wild Atlantic salmon are rarely available commercially due to conservation restrictions, so most Atlantic salmon in stores is farmed.
Verdict
Choose your target based on where you fish. If you’re on the Pacific Coast or near the Great Lakes, coho are your fish — accessible, aggressive, and available in healthy numbers. They hit hard, fight spectacularly, and many fisheries allow you to keep your catch. Target them in summer and fall, focus on river mouths and estuaries during runs, and bring medium spinning or fly gear with 10-15 pound line.
Atlantic salmon fishing is a specialized pursuit requiring access to specific rivers — primarily in Maine, eastern Canada, or landlocked fisheries. The challenge is part of the appeal. You’ll need to master fly fishing techniques, learn to read water, and develop patience for selective fish. The reward is hooking into one of freshwater’s most powerful and acrobatic fighters.
For most anglers, coho offer better odds and easier access. But if you’re near Atlantic salmon water and up for a technical challenge, few fish match the thrill of swinging flies for salmon in a classic river. Both species deserve a place on your bucket list — just fish the one that swims in your backyard first.