By Dr. Sal Benezo
During a hurricane, fish experience dramatic changes in their environment that can affect their behavior, habitat, and survival. As the atmospheric pressure drops with an approaching hurricane, the water pressure at different depths also changes. Fish have swim bladders that help regulate buoyancy, and the rapid changes in pressure can affect how they swim and maintain their depth. Some fish may dive deeper to avoid the surface turmoil.
Hurricanes churn up sediment from the seabed, making the water murkier. This can reduce visibility, affecting how fish find food and avoid predators. In coastal areas, this turbidity can also carry pollutants and toxins from land runoff, negatively impacting the water quality.
Hurricanes generate powerful underwater currents and massive waves. Many fish seek refuge in deeper waters, coral reefs, or underwater structures to avoid being swept away. Shallow-water fish may struggle more to find shelter from the turbulence, which could lead to displacement or death.
Hurricanes often bring a rapid influx of fresh water from rain and runoff, lowering the salinity of coastal waters. Some species, especially those adapted to certain salinity levels, may be stressed or forced to move to more stable areas. Additionally, the mixing of ocean layers can lead to changes in water temperature, which can affect fish metabolism and spawning behaviors.
The disturbance of the water column can disrupt oxygen levels, particularly in areas where organic matter from land washes into the ocean. Decomposing plant material can deplete oxygen in the water, creating hypoxic (low oxygen) zones, which can force fish to flee or risk suffocation.
Fish, especially schooling species, may instinctively move to safer waters before or during a hurricane. Some species seem to sense the change in barometric pressure and migrate to deeper or more sheltered areas ahead of the storm. However, fish that get caught in the turbulent water may end up displaced far from their usual habitat.
After a hurricane, habitats may be altered significantly. Coral reefs, seagrass beds, and mangroves, essential fish habitats, can be damaged, leading to long-term impacts on fish populations. However, hurricanes can also bring benefits, such as replenishing nutrients and oxygen in certain water bodies, which can stimulate plankton growth and temporarily improve food availability for fish.
Fish have evolved to withstand many natural disturbances, including hurricanes, but the intensity and frequency of storms can have lasting effects on fish populations, particularly for those in fragile ecosystems.