Hector’s dolphin, a unique marine mammal, is one of the smallest and rarest dolphin species. Endemic to New Zealand, these dolphins are identified by their distinctive features. They possess a stocky body with striking grey, white, and black markings, and a rounded dorsal fin that resembles a Mickey Mouse ear.
Primary Food Sources
Hector’s dolphins are generalist feeders, consuming a varied diet primarily based on prey size rather than specific species. Their diet consists of small, schooling fish and invertebrates. Key fish species include red cod, ahuru, sprat, and sole (flounder), along with stargazer and barracouta juveniles.
Beyond fish, they also prey on cephalopods like arrow squid and occasionally crustaceans such as crabs. Most prey items are smaller than 10 centimeters, though they can consume fish up to 60 centimeters. Red cod contributes significantly to their diet by mass. Their diet also includes both demersal (bottom-dwelling) and free-swimming prey found throughout the water column.
Hunting and Foraging Habits
Hector’s dolphins are active hunters that employ echolocation to locate their prey in coastal waters. This biological sonar system involves emitting high-frequency clicks that provide dolphins with an acoustic picture of their surroundings and prey location. Echolocation is effective for detecting fish hidden beneath the sand or navigating through turbid conditions.
These dolphins forage individually or in small groups, sometimes forming larger temporary aggregations. Their small size and agility allow them to maneuver effectively in complex shallow environments, pursuing prey near the seabed. They have also been observed foraging near fishing trawlers, likely targeting fish disturbed by the gear rather than those caught in nets.
Influence of Coastal Habitat on Diet
The Hector’s dolphin’s diet is linked to its specific habitat, as these dolphins exclusively inhabit shallow, inshore coastal waters around New Zealand. They are found in waters less than 100 meters deep and often within seven kilometers of the shoreline. This restricted range means their food sources are limited to species thriving within these nearshore environments.
Their diet directly reflects the abundance of small, schooling fish and invertebrates that populate these coastal zones. Seasonal shifts in prey availability within these shallow waters can also influence the dolphins’ movements closer to or further from the shore. Unlike offshore dolphin species, Hector’s dolphins depend on the marine life supported by their unique coastal ecosystem.