Energy Metabolism
A great white shark has a metabolic rate about three times higher than the average sea creature. Sharks burn fuel efficiently. Metabolism ( exchange of energy and materials with the environment). The study of energy flow is called thermodynamics. Sharks cannot manufacture their own energy to maintain itself. They steal energy from plants or other animals. Great white sharks power their journey with energy stored as fat and oil in their livers. This helps us understand how important their habitats are as fueling stations.
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Build up blubber to later burn off on their migrations. Carry fat in their lives instead of on the external blubber.
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Body mass is correlated to the amount of stored oil in the liver.
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Oil accounts for a ¼ of their body weight
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"They carry a huge store of energy in the form of oil in their massive livers, but they also depend on that volume of oil for buoyancy. So, if they draw on those reserves, they become heavier and heavier." https://news.stanford.edu/news/2013/july/sharks-fuel-source-071713.html
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Largest fish with regional endotherms
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Sharks are apex marine predators. They have a circumglobal distribution. They are highly susceptible to overexploitation due to their longevity, late maturity around 15 years old, and low fecundity renders. The population is poorly known due to the lack of indicators that are given to protect them. White sharks are caught in traps.
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Sharks repeatedly dive around 29m and swim at the surface between deep dives, maxing out around 108m. Swim speeds average around 0.80-1.35 ms^-1/
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Metabolic rates derived from the estimated swimming speed that helps understand their feeding.
“Energy requirements of large sharks are poorly documented. The only published study of white shark energetics in the wild estimated the field metabolic rate (MR) of a single individual from telemetered muscle temperature data as the individual moved from cold to warm water12. The authors used their MR estimates to suggest a 943 kg white shark could survive on 30 kg of marine mammal blubber for approximately 1.5 months; a widely cited figure that has perpetuated the assumption that large sharks only need to feed every few weeks to maintain net energy gain.” https://www.nature.com/articles/srep01471
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When a shark eats a meal, it consumes energy in the form of chemical bonds, it holds atoms together in a stable arrangement, this is called molecules. During digestion, the molecules are broken down and absorbed through the intestinal walls.
During a study, a shark was tracked for 3 ½ days in deep waters. The shark moved 190 km. It made one excursion to the surface and then back down. The muscle temperature of the shark was 5 C warmer than the surrounding water. It functions as heat exchangers. Due to the warming of the muscle as the shark swims into warmer temperature water, it has allowed us to estimate the rate of metabolism. Sharks can swim for a month without having to feed, if they eat a large meal prior to beginning their journey.
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Large retia mirabilia allows sharks to raise their internal temperature higher than surrounding water.