Sharks are marine predators whose survival and ecological roles are closely tied to water temperature. This relationship explains how they thrive across diverse marine habitats.
Understanding Shark Temperature Needs
Most sharks are ectothermic, meaning their body temperature largely mirrors the surrounding water. While they inhabit a wide range of ocean temperatures, from frigid polar regions to warm tropical seas, most species prefer warmer, temperate to tropical waters.
Tropical waters, typically 21°C to 30°C (69.8°F to 86°F), are home to many shark species year-round. Temperate regions, with temperatures between 10°C and 21°C (50°F and 69.8°F), also support large shark populations. Even polar regions, where waters stay below 5°C (41°F), host specialized shark species adapted to cold conditions.
The Biological Impact of Water Temperature
Water temperature fundamentally impacts shark physiology. As ectotherms, their metabolic rate is directly influenced by water temperature. When temperatures drop, a shark’s metabolic rate decreases, impacting essential functions like vision, nerve impulse transmission, and muscle activity.
Temperature affects oxygen consumption in sharks, with rates generally increasing in warmer waters. Extreme cold can impair a shark’s ability to move and breathe. Conversely, excessively warm waters can speed up metabolism, leading to increased energy demands and reduced nutrient absorption.
Diverse Temperature Preferences Among Shark Species
Shark species exhibit varied water temperature preferences, reflecting adaptations to specific marine environments. Tropical species like nurse, tiger, and bull sharks thrive in warm waters, often between 20°C and 30°C (68°F and 86°F). Nurse sharks are non-migratory, remaining in warm areas. Blacktip reef sharks also prefer warm, shallow waters ranging from 21°C to 30°C (70°F to 86°F) around coral reefs.
In contrast, some species are adapted to cold water environments. The Greenland shark, for example, inhabits arctic and subarctic waters where temperatures typically range from -2°C to 7°C (30°F to 45°F). These sharks have physiological adaptations enabling them to function in extreme cold. The Pacific sleeper shark is another cold-water adapted species.
Large sharks like the great white possess regional endothermy, enabling them to tolerate a wider range of temperatures, typically between 12°C and 24°C (54°F and 75°F). Shortfin mako sharks, another partially warm-blooded species, live within a narrower range of about 17°C to 22°C (62.3°F to 71.6°F).
Temperature’s Influence on Shark Behavior and Distribution
Water temperature significantly impacts shark behavior and distribution. Many species undertake extensive migrations, often driven by seasonal changes in water temperature and prey availability. Sandbar sharks, for example, migrate north in spring as water temperatures rise to 16°C (60.8°F) in their northern range.
Water temperature changes can shift shark populations and migratory routes. Tiger shark migrations, for instance, have extended farther poleward and they arrive earlier in northern areas during periods of high sea-surface temperatures. This can alter predator-prey interactions and lead to ecological imbalances. Warmer ocean temperatures can also affect shark breeding and increase disease outbreaks in some species.
Highly migratory species, like blue sharks, can swim across entire ocean basins and tolerate a wide range of temperatures, from 3.9°C to 31°C (39°F to 87.8°F), by adjusting their depth. However, prolonged exposure to temperatures outside their preferred range can increase their metabolic rate, demanding more oxygen and affecting survival.