The Atlantic cod (Gadus morhua) is one of the most iconic fish in the North Atlantic ocean These large, bottom-dwelling fish have been an important food source for coastal communities for centuries But what exactly do cod eat to get so big? As it turns out, cod have a remarkably diverse diet that changes throughout their lifetimes.
Plankton and Small Invertebrates – The Staples of a Young Cod’s Diet
When cod first hatch from their eggs as tiny larvae, they immediately begin feeding on plankton. Plankton are microscopic organisms that drift along ocean currents and serve as the foundation of the marine food chain. By consuming phytoplankton, larval cod gain sustenance and energy to grow.
As juvenile cod grow larger, they start preying on small invertebrates like copepods, krill, and amphipods. Copepods are particularly important, making up over 50% of a young cod’s diet. These tiny crustaceans provide protein and nutrients to help cod continue growing into adults.
Larger Invertebrates – Clams, Crabs, Shrimp and More
Within their first year, cod have typically grown large enough to start eating bigger invertebrate prey. Some of their favorites include
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Clams, mussels, and oysters – Cod use their powerful jaw muscles to crush the shells and access the nutrient-rich meat inside.
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Shrimp and prawns – Cod will chase down these quicker crustaceans and swallow them whole.
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Crabs and lobsters – Larger cod can swallow small crabs and lobsters in one gulp.
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Squid and octopi – These cephalopods are common prey for adult cod, providing protein.
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Sea worms and eels – Cod will dig up bottom-dwelling worms and swallow eels whole.
By diversifying their diets with these larger invertebrates, cod obtain a wide array of vitamins, minerals, healthy fats, and protein. This helps them continue growing into formidable predators.
Small Fish – Cod Cannibalism is Common
Once cod reach adulthood and exceed 60cm in length, they add small fish to their diets. Some of the most common fish prey include:
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Capelin – These small, oil-rich fish travel in large schools, making for easy targets.
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Sand lance – Another schooling fish that cod will consume in large numbers.
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Atlantic herring – These abundant fish are an important source of calories for cod.
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Juvenile cod – Shockingly, cod do not hesitate to eat smaller members of their own species. This cannibalism helps larger cod consolidate resources.
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Other small fish – Cod are opportunistic and will eat any small bait fish they can capture, including sand eels, rockling, and more.
For larger cod, fish become the main part of their diet and provide the bulk of their nutrition. Schools of smaller fish are easy targets for these master predators.
Hunting Strategies – How Cod Catch Their Prey
Cod are cunning hunters that use a variety of techniques to catch their prey:
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Stalking – Cod will hunker down and stealthily approach unsuspecting fish and crustaceans. They then rush forward and inhale their prey.
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Ambushing – By hiding in rocky crevices, cod can wait to ambush passing fish and seize them.
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Luring – Using a dorsal fin lure, cod can attract smaller fish then suck them into their mouths.
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Foraging – Cod use their barbels to feel along the seafloor and dig up buried invertebrates.
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Trapping – Schools of cod will circle and trap bait fish before attacking from all sides.
By mastering these hunting strategies, cod can consume a wide range of prey. The most successful hunters grow into giants exceeding 1.5 meters long.
Changing Diets Throughout Life Stages
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Larval cod – Plankton
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Juvenile cod – Copepods, krill, amphipods
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1-2 year olds – Larger invertebrates like clams, crabs, shrimp
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Adult cod – Small fish like capelin, herring, and juvenile cod
This dietary flexibility allows cod to take advantage of the most abundant food sources available in their habitats. By shifting their targets, cod receive proper nutrition during each phase of growth.
Threats to Cod Food Supply
Unfortunately, human activities are now threatening Atlantic cod’s food supply. Warming oceans and overfishing are depleting populations of prey species. As key food sources disappear, cod growth and survival is hindered.
Protecting smaller bait fish and invertebrates is crucial to restoring cod populations to healthy levels. If their prey cannot rebound, cod may not be able to either. Careful management of both cod and their prey species is needed to preserve these iconic predators for future generations.
In conclusion, Atlantic cod are voracious predators with highly diverse and flexible diets. By consuming plankton, invertebrates, and fish, they obtain the energy needed to grow into giants. However, overfishing and climate change now threaten cod’s food supply. Protecting cod prey species is essential to ensure the future of this commercially and ecologically important fish.
What Is Cod?
Cod is a firm, white fish that is often grilled, baked, steamed, fried, or broiling. It is popular in foods all over the world. Cod comes in two main types: Atlantic cod (Gadus morhua), which lives in the cold waters of the North Atlantic Ocean, and Pacific cod (Gadus macrocephalus), which lives along the coasts of North America, Asia, and Russia in the Pacific Ocean. Cod is from the same family, Gadidae, as haddock, whiting and pollock.
People have been eating salt cod, which is made by salting and drying cod, for hundreds of years along the Atlantic coast of North America, in the Caribbean, Europe, and South America. It is known as the prosciutto of the sea.
Cod Vs. Salmon Vs. Haddock Vs. Tilapia
A lot of people compare cod, salmon, haddock, and tilapia to each other because they are all very popular fish. Haddock and tilapia are the most like cod in terms of taste and texture. They are both firm, white fish with a mild flavor that cooks well in a variety of ways. Salmon, on the other hand, is more of a fatty fish with a stronger flavor.