Monthly Archives: January 2018

What is the difference between Atlantic and Pacific Salmon?

How are Atlantic and Pacific salmon related, and how do their lifecycles differ?

I’ll start with the obvious answer. Atlantic salmon are originally from the Atlantic Ocean, while Pacific Salmon are from the Pacific Ocean. You probably already knew that, though. Atlantic and Pacific salmon belong to the family Salmonidae, but Pacific salmon belong to the genus Oncorhynchus while Atlantic salmon (Salmo salar) are the largest members of the genus Salmo. Atlantic salmon are more closely related to certain species of trout, such as brown trout (Salmo trutta) than they are to Pacific salmon. Atlantic salmon have large, black spots on their gill covers and back.

The lifecycles of natural populations of Atlantic and Pacific salmon are similar. Atlantic salmon spend one to four years in the ocean before returning to spawn in the freshwater stream where they were born. One big difference, though, is Atlantic salmon don’t always die after they spawn. Pacific salmon are semelparous, meaning they die after they spawn. Atlantic salmon are iteroparous which means they may recover, return to the sea, and repeat the migration and spawning pattern. Spawning takes a huge physiological toll on a salmon, though, and most Atlantic salmon do not survive to spawn a second or third time.

Are Atlantic or Pacific salmon healthier to eat?

Controversy swirls over the health benefits of eating Atlantic and Pacific salmon. This debate has nothing to do with wild Atlantic salmon, though. Most salmon sold in the U.S. are farmed Atlantic salmon. Salmon sold as “wild” salmon are Pacific salmon. Sadly, most wild Atlantic salmon stocks were wiped out or severely depleted years ago by over-fishing, but in a few places, these wild stocks are recovering.

What are the health differences between eating a wild or farmed salmon?

Salmon are good for you. Both wild and farmed salmon are high in Omega-3 fatty acids, a fat with many health benefits. Farmed salmon, though, also have other fats that are not as good for humans. A half-pound filet of wild salmon has 281 calories, while a half-pound fillet of farmed salmon contains 412 calories. Farmed salmon is loaded with twice as much fat as wild salmon and three times more saturated fat. Wild salmon pack more calcium, iron, potassium, and zinc and less sodium than farmed salmon. Depending on the farm, farmed salmon may have higher levels of contaminants than wild salmon, but biologists believe farmed salmon are safe to eat.

Most experts agree if you have a choice, eat wild salmon, but farmed salmon are better than no salmon and farmed salmon are more readily available and can be found year-round.

I think the biggest difference to me is taste. Wild Pacific salmon has a rich, robust taste, while farmed salmon often tastes bland.

One of the biggest concerns about farmed salmon for biologists is the salmon will escape their pens and become an invasive species. How these farmed salmon might affect populations of wild salmon, no one knows, but biologists fear farmed salmon that have been fed antibiotics might spread diseases to wild salmon.

In 2017, 300,000 Atlantic salmon escaped from a farm in the San Juan Islands in Puget Sound, Washington, and alarmed Alaska Fish and Game biologists sent out an alert to all anglers to be on the lookout for invasive Atlantic salmon.

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Why Do Salmon Jump And Other Questions

Why do salmon jump?

This is the question our guests most frequently ask about salmon as they watch fish pop out of the water around them. The answer is: no one knows. Some speculate salmon jump to loosen their eggs from the membrane encasing them, but males also jump, so this reasoning doesn’t work. Another explanation is they jump to catch flying insects, but their jumping behavior increases in frequency as they near their spawning stream at the same time their digestive system is shutting down and they stop feeding, so this explanation also is not valid.

I like to tell our guests the salmon they see jumping are teenagers. As a salmon prepares to spawn, its hormones rage and its body changes color and shape. These jumping fish are the equivalent of a human teenager, so they act like teenagers. While this explanation is always good for a laugh, there is no scientific evidence to support it.

My opinion, for what it’s worth (and not much, since there is also no scientific evidence to support this), is salmon have evolved to jump because jumping is beneficial to their survival. Salmon that have inherited the genetic characteristic to jump when they near their home stream are more likely than those who cannot jump to make it upstream and spawn. They then pass along this trait to jump to their offspring. Evolution has selected this jumping trait. Most salmon spawn in small streams and they must navigate shallow water, rapids, and sometimes even waterfalls. If they couldn’t jump, many salmon would never make it to their spawning grounds. Again, this explanation is only my opinion, but I believe it has some merit.

The correct answer to the question, “Why do salmon jump?” is: no one knows.

Do all salmon return to spawn in the same river or stream in which they were born?

No. A small percentage of salmon spawn somewhere other than where they were born. This behavior is called “straying,” and it is adaptive because it allows salmon to colonize streams that do not currently have a salmon population. It also allows salmon to spawn somewhere if the stream where they were born no longer exists. Pink salmon and chum salmon both often spawn close to the mouths of small streams. If these streams are diverted by winter storms, as often happens, the returning salmon will stray to a nearby stream.

When a salmon returns from the ocean, how does it find its spawning stream?

Salmon must navigate a long distance from the open ocean to their spawning stream. Evidence shows they use magnetic cues, the position of the sun, and day length to know when to begin their migration back to their natal stream and how to get there. Once salmon near and enter fresh water, scientists think they use their sense of smell to find not only their home stream or river but the specific tributary or area of the river where they were born. Juvenile salmon imprint on the unique chemical signatures of the waters where they were born and occupied as fry as well as on the waters they migrated through to get to the ocean. When they return to spawn, they follow this chemical smell back to where they were born.

How many salmon eggs hatch, develop, and return as adults to spawn?

Salmon have tough lives. From the egg stage, until they spawn and die, they are a food source for a wide variety of fish, birds, and mammals, including man. Biologists estimate 1 in 1000 eggs will develop, find their way to the ocean, swim back to their natal stream, and spawn. Depending on the species and the age of the fish when she spawns, a female salmon lays between 1000 and 6000 eggs, so the survival rate is not good.

I hope I’ve answered a few of your questions about the amazing Pacific salmon. Next week, I will tackle a big question. What is the difference between Atlantic and Pacific salmon?

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If you haven’t seen my webinar on how I became an author and why I write Alaska wilderness mysteries, this is the link: http://bit.ly/2pcCOo6. If you like it, please share it with your friends. The free book offer is sincere, and there is no catch. Also, please sign up for my free, monthly newsletter about true murder and mystery in Alaska. This month I am writing about the Fairbanks Four. Four young men spent 18 years in prison for a murder they didn’t commit. 

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Which Salmon Is It?

Over the past several weeks, I’ve been writing about Pacific salmon, so this week, I want to pause a minute and review. In their marine phase, the five species of Pacific salmon are hard to tell apart. Their life cycles are similar, and sometimes all five species spawn in the same river/lake system. What are their differences, and how do you tell one species from another?

Perhaps you are thinking, why should I care if I can differentiate between salmon species? Let’s pretend you are fishing in Alaska on a river where all five Pacific salmon species are present. It is legal to keep pink salmon, chums, and cohos, but you must release sockeyes and kings. You catch a beautiful, silvery salmon. You know right away it hasn’t been in fresh water long enough for its color and body shape to change. You also know if it is still silver in color, its flesh will be firm, and it will be good to eat. Is this one of the species you can keep, or must you release this fish?

The size of the fish is a clue, but often, different year classes of a species return to the same river, so size is not definitive. Does the fish have spots, and if so, where and how big? Spots are more visible when a salmon gains its spawning coloration, but if you look closely, the spots are visible in the silvery marine phase. Pink salmon have large, oval spots on the back and both lobes of the tail. Cohos have small black spots on the back and the upper lobe of the tail. Kings have spots on the back and both lobes of the tail. Sockeyes and chums have no spots on their backs or tails.

While you are looking at the tail, do you see any silver streaks? Cohos and kings have silver streaks radiating along the rays of the tail. Chums also have silver streaks but only on half the tail.

The mouth is another distinguishing characteristic. King salmon have a black mouth with a black gum line and a black tongue. Pinks also have a black gum line, but they have a white mouth. The other three species all have white mouths and white gum lines.

A chum salmon has a white tip on the anal fin, an important characteristic to note when trying to differentiate a chum from a sockeye.

Other distinguishing characteristics you can use include the size of the eye, scale size, and the shape of the tail, but none of these are easy to employ unless you are comparing one salmon to another.

Take a look at the salmon you caught. It weighs about four pounds and has spots on the back and both lobes of the tail. You think you see silver streaks in the tail, but you’re not certain, so you check the mouth and note a black gum line and a black mouth. You are allowed to keep the fish if it is a pink,  chum, or silver salmon, but you must release it if it is sockeye or king. Will you be able to grill this salmon for dinner, or should you carefully release it back into the stream?

The size of the fish, and the spots on the back and both lobes of the tail may lead you to jump to the conclusion you caught a pink salmon, and you can keep it. Only pinks and kings have spots on both lobes of the tail, so you can quickly rule out the other three species. The silver streaks in the tail may be hard to see, so you wisely check the mouth. Both pinks and kings have black gum lines, but only king salmon have a black mouth, including a black tongue. Take a closer look at the fish. Are the spots small or are they large and oval? If you said small, you have your answer. You caught a small, probably a mature 3-year-old king salmon, and you must release it.  

It takes practice to identify a silvery Pacific salmon in its marine phase. Commercial fishermen can quickly differentiate one species from another, but if you only occasionally fish for salmon, one silver salmon looks much like the next. If you can’t identify the salmon you caught, you must release it, so if you plan to go salmon fishing in Alaska without a guide, you should do your homework first.

Next week, I’ll write about some of the questions we are commonly asked about salmon, and I will do my best to answer them.

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I am excited to announce the webinar I told you about last week explaining how I became an Alaska wilderness mystery writer and where I get some of my ideas for my novels, has now been released. To see the webinar, follow this link: http://bit.ly/2pcCOo6. I used many of Mike’s photos and my friend, Ryan Augustine’s photos and videos in the webinar, so I think you will enjoy it. Please share the webinar link with your friends and family. If you stay until the end, you can get a free e-book of one of my novels. The purpose of the webinar is to introduce myself and my books to a wider audience, so the more you share this link, the happier I will be! Thank you!

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