Salmon are amazing fish that have captivated humans for millennia. Their rich pink flesh, immense size, and incredible migratory patterns have made them a prized food source and cultural icon. But there is still much debate around whether salmon are vertebrates or invertebrates. In this article, we’ll explore the biology of salmon to uncover the truth.
What Are Vertebrates and Invertebrates?
Vertebrates and invertebrates are broad categories used to classify animals. Vertebrates are animals that possess a backbone or spinal column. This includes fish, amphibians reptiles birds, and mammals. Invertebrates, on the other hand, are animals without a backbone. This highly diverse group includes insects, spiders, worms, jellyfish, and shellfish.
The presence or absence of a backbone is an important anatomical distinction The vertebral column provides structural support and protection for the spinal cord and nerve roots, It also enables movement and facilitates balance Only vertebrates possess this defining anatomical feature,
The Biology of Salmon
Salmon belong to the family Salmonidae which includes trout, char, grayling, and whitefish. They are bony fish with a distinct fusiform body shape optimized for swimming upstream against currents. Salmon range in size from 1 to 5 feet long and can weigh anywhere from 8 to 120 pounds.
The skeletal structure of salmon includes a skull, vertebral column, ribs, and fin rays. Their vertebral column is composed of individual vertebrae that surround and protect the spinal cord Salmon possess between 52-58 vertebrae depending on the species Their rib bones connect to the vertebrae and protect internal organs.
Salmon anatomy clearly contains the defining feature of a vertebrate – the backbone. Their internal skeletal structure provides support, facilitates movement, and protects the spinal cord and nerves. From a biological perspective, there is no question that salmon are vertebrates.
Common Misconceptions
Given their obvious vertebrate anatomy, where does the misconception of salmon as invertebrates come from? There are a few possible explanations:
Lack of visible backbone: When you eat a salmon steak or fillet, the backbone is removed, leaving just the meat and ribs. This can give the impression that salmon lack a defined spine.
Confusion with other seafood: Shellfish like oysters, mussels, and shrimp are common invertebrate seafood. Their popularity may lead some to assume salmon are invertebrates too.
Similarity of appearance: Salmon and some large invertebrates like squid have a generally comparable torpedo-like shape. This could visually suggest a shared anatomy.
Unfamiliarity with fish anatomy: People unfamiliar with the internal anatomy of fish may not realize the vertebral column is present but obscured from view.
While these reasons may explain the misconception, they do not change the biological reality – salmon are clearly vertebrates.
Fascinating Facts About Salmon
Now that we’ve settled the vertebrate-invertebrate debate, here are some amazing facts about these incredible fish:
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Salmon hatch in freshwater but spend their adult lives at sea, making epic migrations between the two. Some species swim more than 900 miles each way!
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Salmon use their keen sense of smell to identify their exact natal stream and headwaters to spawn. Scientists think they may memorize the stream’s unique scent as juveniles.
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Grizzly bears rely heavily on salmon runs for food. They can eat up to 4% of their body weight daily when salmon are available.
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Salmon change color during spawning migrations, turning vibrant red or orange. This is due to changes in diet and hormone levels.
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Salmon are anadromous, meaning they migrate from saltwater to freshwater to spawn. Some trout species are catadromous, doing the reverse migration.
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Fossil records show salmon have remained anatomically unchanged for 50-60 million years. Their unique biology is optimized for their environment.
So while salmon may seem mysterious in some ways, one thing is certain – they are vertebrates through and through! Their internal spine and backbone clearly identify them as members of this broad biological classification. Next time you eat a salmon steak, take a moment to appreciate this fascinating vertebrate!
Nutrition Facts Servings: 1; Serving Weight: 100 g (raw); Calories: 142; Protein: 19.84 g; Total Fat: 34 g; Total Saturated Fatty Acids: 0.981 g; Carbohydrate: 0 g; Total Sugars: 0 g; Total Dietary Fiber: 0 g; Cholesterol: 55 mg; Selenium: 35 mcg; Sodium: 44 mg
Farmed Atlantic salmon makes a delicious, healthy meal! If you need some cooking inspiration, browse these recipes for salmon sushi cups, easy pesto salmon, and more!
Where Gulf of Maine Atlantic Salmon Live
Young salmon spend 2 to 3 years in the rivers and streams of Maine, then undergo physical changes to prepare them for life in the ocean. Once Gulf of Maine Atlantic salmon leave Maine streams and rivers, they migrate to the ocean. Some salmon return to Maine after their first winter at sea, but most spend a second year feeding in the Labrador Sea off the southwest coast of Greenland. Most Gulf of Maine salmon return to rivers in Maine after two winters at sea.
Atlantic salmon are endangered, with only a few runs remaining in Maine rivers.
The Gulf of Maine population of Atlantic salmon has declined significantly since the late 19th century. Historically, dams, overfishing, and pollution led to large declines in salmon abundance. Improvements in water quality and stocking from hatcheries helped rebuild populations to nearly 5,000 adults by 1985, but in the early 1990s there was a substantial decrease in marine survival that contributed to a significant population decline. Since 2015, annual returns to Gulf of Maine rivers have averaged less than 1,200. The rapid decline and dire status of the ESA-listed Gulf of Maine DPS makes it a priority for NOAA Fisheries and partners to prevent its extinction and promote its recovery.
Dams limit or block salmon access to important habitats in Maine. More than 90 percent of Maines rivers and streams are affected by dams, which directly kill or injure a significant number of Atlantic salmon on upstream and downstream migrations. Dams also harm important habitats by flooding free-flowing rivers, reducing water quality, and changing fish communities. Finally, dams worsen the effects of climate change by limiting Atlantic salmons access to cool-water habitats in higher elevation areas in Maine. Of the more than 400 dams along rivers and streams that support wild Atlantic salmon, only 75 have fishways, a structure that allows fish to swim around dams to reach their spawning grounds.
Coopers Mill Dam in 2016 before dam removal by Atlantic Salmon Federation.
Gulf of Maine DPS salmon survival in the ocean has decreased over the last 25 years. This means that an increasing number of salmon die in the ocean before they can return to Maine to spawn. Many Atlantic salmon die in the ocean due to predation, starvation, diseases and parasites, and changing ocean conditions. Marine survival is poor throughout the Atlantic Ocean and is affected by both nearshore and open ocean survival rates. This ongoing and significant threat has pushed populations of Atlantic salmon in the United States closer to extinction. The North Atlantic Salmon Conservation Organization leads international efforts to control and better manage foreign fisheries to reduce their impacts on Atlantic salmon born in the United States. Not all causes of low ocean survival are well-known. Threats like climate and ocean changes, plus shifts in predator and prey abundance and distribution, appear to affect salmon survival at sea.
Atlantic salmon coming out of the top of the Milford fish lift on the Penobscot River.
To work toward recovery of these fish, NOAA Fisheries and the U.S. Fish and Wildlife Service worked with scientists, tribes, and other partners to develop a recovery plan, which was finalized in February 2019. The recovery plan builds upon scientific studies and other observations and information sources to identify gaps in our knowledge and the research needed to fill those gaps. The recovery plan also identifies specific criteria that will signal the recovery of the species.
Primary threats with the potential to limit recovery of the Gulf of Maine DPS of Atlantic salmon include:
- Dams and road stream crossings
- Climate change
- Low marine survival
- Loss of genetic diversity
Additionally, the recovery plan identifies numerous secondary threats that, when combined, significantly affect the species chance of survival and recovery. They include:
- Reduced freshwater habitat complexity
- High catch rates in international fisheries
- Reduced instream flow
- Reduced water quality
- Disease
- Predation
- Depleted diadromous fish communities
- Artificial propagation
- Aquaculture
- Competition with non-native fish species
We work closely with the Penobscot Nation, the U.S. Fish and Wildlife Service, and the Maine Department of Marine Resources to manage Atlantic salmon cooperatively under the Collaborative Management Strategy for the Gulf of Maine DPS Atlantic Salmon Recovery Program.
Salmon Life Cycle
FAQ
Are salmon vertebrates or invertebrates?
Students will probably name foods such as fish and shellfish. Ask them to categorize their suggestions into “vertebrates” and “invertebrates.” Under vertebrates they might include bony fish with which they are familiar such as tuna, salmon, flounder, cod, halibut, and sole.
Is a fish an invertebrate?
No, a fish is not an invertebrate. Fish are vertebrates, meaning they have a backbone or spinal column.
What type of organism is a salmon?
Salmon (/ˈsæmən/; pl. : salmon) are any of several commercially important species of euryhaline ray-finned fish from the genera Salmo and Oncorhynchus of the family Salmonidae, native to tributaries of the North Atlantic (Salmo) and North Pacific (Oncorhynchus) basins.
What animal group is a salmon?
Salmon: the common name for several species of ray-finned fish in the family Salmonidae. There are seven species of Pacific salmon.Dec 10, 2021