Identifying coho and king salmon is an essential skill for any angler fishing in Alaska’s pristine waters, especially around Seward. These two salmon species are prized for their size, fighting ability, and culinary appeal, making them some of the most sought-after catches in the region. However, their similar appearances can lead to confusion, which is why proper identification is crucial—not only to follow fishing regulations but also to contribute to sustainable fishing practices.
In this guide, we’ll break down the key differences between coho and king salmon, including size, coloration, fin shapes, and behavioral traits. You’ll also learn practical tips for identifying these fish in the wild and avoiding common mistakes. Whether you’re a seasoned angler or just starting your fishing journey, this blog will help you confidently distinguish between these iconic salmon species.
Overview of Coho and King Salmon
What Are Coho and King Salmon?
Coho salmon (Oncorhynchus kisutch), often referred to as silver salmon or silvers, are a medium-sized species found in the North Pacific Ocean and coastal rivers. Known for their vibrant silver bodies and aggressive behavior on the line, coho are a favorite among anglers for their sporting qualities and excellent table fare. They typically weigh between 6 and 12 pounds, though larger specimens are not uncommon.
King salmon (Oncorhynchus tshawytscha), or chinook salmon, are the largest Pacific salmon species, earning them the title of “king.” These fish can reach impressive sizes, with some weighing over 50 pounds. Their rich, fatty meat makes them a culinary delight, while their size and strength offer a thrilling challenge for anglers. Kings are most commonly found in deeper waters and larger rivers, making Seward an ideal destination for King and Silver Salmon fishing in Alaska.
Why Identification Matters for Anglers
Accurate identification of coho and king salmon is essential for several reasons. From a regulatory perspective, each species has specific bag limits, size restrictions, and seasonal closures to ensure sustainable populations. Misidentification could lead to unintentional violations, which may result in fines or other penalties.
Beyond compliance, proper identification enhances the overall fishing experience. Knowing what you’ve caught allows you to appreciate the unique traits of each species, from the fight they put up to their culinary differences. Furthermore, understanding these species helps anglers contribute to conservation efforts, ensuring future generations can enjoy the same thrilling opportunities.
This foundational knowledge sets the stage for identifying key differences between coho and king salmon, which will be explored in detail in the next section.

Key Differences Between Coho and King Salmon
Size and Weight
One of the most noticeable differences between Alaska Silver Salmon and Alaska King Salmon is their size. Coho salmon are smaller, typically weighing between 6 and 12 pounds, with some individuals reaching up to 20 pounds in exceptional cases. They generally measure around 24 to 30 inches in length, making them a manageable catch for most anglers.
King salmon, true to their name, are significantly larger. They can weigh anywhere from 15 to over 50 pounds, with some record-breaking fish exceeding 100 pounds. Their length ranges from 30 to 50 inches, making them the largest of all Pacific salmon species. Anglers targeting kings often need heavier gear to handle the sheer power and weight of these fish, while coho can be pursued with lighter tackle.
Coloration and Markings
Coloration is a key feature for identifying both species, though it can vary depending on their life stage. Coho salmon are renowned for their bright silver bodies, which give them the nickname “silver salmon.” During spawning, their bodies take on a reddish hue, particularly along their sides and belly, while their backs darken.
King salmon have a more subdued color palette. In their ocean phase, they display a blue-green back, silver sides, and a white belly. Spawning kings develop a darker, often reddish or bronze tone. A distinctive feature of king salmon is their black gum line, which remains consistent throughout their life and can be a reliable identification marker.
Tail and Fin Differences
The tails and fins of coho and king salmon offer additional clues for differentiation. Coho salmon have a slightly forked tail with fewer distinct spots, primarily concentrated on the upper lobe. Their dorsal fin is generally smaller and less pronounced, with subtle spotting.
King salmon, on the other hand, have a more robust and squared tail that is heavily spotted across both lobes. Their dorsal fin is larger, with pronounced spotting that is more noticeable even from a distance. These differences become particularly useful when handling a fish in low-light conditions or turbid waters.
Mouth and Teeth
Examining the mouth and teeth can provide a definitive way to distinguish between coho and king salmon. Coho salmon have a lighter gum line, with white or grayish hues that contrast with their teeth. Their teeth are relatively smaller and less pronounced, which aligns with their smaller size and diet preferences.
King salmon have a distinctly black gum line that stands out against their teeth, even in juvenile stages. Their teeth are larger and more robust, reflecting their position as apex predators in the ecosystem. This feature is particularly helpful when identifying fish that have similar body coloration but differ in mouth structure.
Understanding these key physical differences between coho and king salmon ensures that anglers can confidently identify their catch, avoid mistakes, and appreciate the unique characteristics of each species.

Tips for Anglers to Identify Coho and King Salmon in the Wild
Visual Cues to Look For
When identifying coho and king salmon in the wild, visual characteristics are the first and most straightforward indicators. Coho salmon are easily recognized by their bright, metallic silver bodies, especially during their ocean phase. Their bodies have a sleek, streamlined appearance with minimal spotting on the upper lobe of their tails. During spawning, their sides transition to a reddish hue, which can sometimes be mistaken for other salmon species, so it’s important to note other features.
King salmon, by contrast, are bulkier and have a more muted silver sheen. Their black gumline is a telltale sign, even from a quick glance when handling the fish. King salmon also have distinct spotting patterns, with spots covering both lobes of their tail and extending onto their dorsal fin, making them more visually patterned compared to coho salmon.
Behavioral Traits
Behavioral traits provide additional clues for distinguishing between coho and king salmon. Coho salmon are known for their acrobatic displays when hooked, often leaping out of the water and making quick, darting runs. This makes them a favorite among anglers seeking a more dynamic fight. They are commonly found in shallower waters and near river mouths, particularly during their spawning migration.
King salmon, on the other hand, are powerhouses. They tend to stay deeper in the water and rely on their sheer strength rather than agility. When hooked, king salmon often make long, sustained runs, testing the angler’s patience and gear. They also prefer deeper channels and larger rivers, making them slightly more predictable in their habitat preferences.
Tools and Resources for Identification
Anglers should take advantage of tools and resources to ensure accurate identification in the field. A laminated salmon identification chart is a practical tool to keep on hand, providing side-by-side comparisons of coho and king salmon features. There are also mobile apps available that allow anglers to upload photos for real-time identification help.
Booking fishing charters in Seward is another valuable resource, as local guides have firsthand knowledge and can teach you how to spot the differences quickly. Guides often share tips tailored to the region, such as where specific salmon species are more likely to be found during different times of the year, helping you make the most of your time on the water.
By combining visual observation, behavioral insights, and practical tools, anglers can confidently identify coho and king salmon in the wild, ensuring they stay compliant with regulations and enhance their overall fishing experience.

Common Mistakes and Misidentifications
Overlapping Features That Can Be Confusing
One of the most common mistakes anglers make is relying solely on a single characteristic to identify coho and king salmon. For instance, both species have a silver sheen in their ocean phase, which can make them look nearly identical at first glance. This is especially true when lighting or water clarity is poor. Similarly, during spawning, the reddish hues of coho salmon can resemble the darker tones of king salmon, further adding to the confusion.
Another overlapping feature is their tail spotting. While coho salmon have spots concentrated on the upper lobe of the tail and king salmon have spots on both lobes, these differences can be subtle. A quick, untrained look may result in misidentification, particularly for anglers who are new to Alaskan salmon fishing.
Stories from the Field
Misidentifications can happen even to experienced anglers, especially when under pressure to quickly release or keep a catch. For example, a common scenario involves mistaking a smaller king salmon for a large coho due to its size falling into the overlapping weight range. This can lead to unintentional regulation violations if anglers keep a fish assuming it’s within legal limits for coho salmon.
Another frequent mistake occurs during spawning season when coloration changes can throw off even seasoned fishermen. Kings with a slight reddish tinge might be assumed to be cohos, and vice versa. The best way to avoid these errors is to look for a combination of features—such as gumline color, body shape, and spotting—rather than relying on a single trait.
Quick Tips to Avoid These Mistakes
To reduce the risk of misidentifications, anglers should take their time to closely examine their catch. If unsure, start by checking the gumline: coho salmon have lighter gums, while king salmon have a distinct black gumline. Tail spotting and overall size should be the next factors to evaluate.
It’s also important to have a clear understanding of local fishing regulations. In Seward, Alaska, guides and fishing charters often provide updated information on bag limits and size restrictions, which can vary depending on the species. Utilizing identification tools like laminated charts or mobile apps ensures you have a quick reference, even in challenging conditions.
By learning from common mistakes and applying a careful, multi-factor approach, anglers can confidently identify their catch and avoid unnecessary fines or penalties.

Next Steps for Alaska Bound Anglers
Identifying coho and king salmon is a vital skill for any angler fishing in Alaska. By understanding their differences in size, coloration, tail spotting, and gumline, you can confidently distinguish between these two iconic species. Avoiding common mistakes, relying on visual and behavioral cues, and using helpful tools can further ensure accurate identification, especially in Seward’s abundant waters. Properly identifying your catch not only enhances your fishing experience but also helps maintain sustainable fisheries and compliance with regulations.
Ready to put your salmon identification skills to the test? Book a guided fishing trip with Gray Light Sportfishing and Captain Andy Mezirow. With years of local expertise, Captain Andy will help you target these amazing fish on your next trip for coho and King Salmon fishing in Alaska to make your trip memorable and successful. Don’t miss the chance to experience Seward’s world-class fishing—book your charter today!