The Maui Ocean Center, located in Wailuku, is definitely a “locals-only” facility. In this case, the “locals” are animals indigenous to the waters surrounding the Hawaiian Islands. At the Center, visitors are able to see in close proximity the marine life of the Pacific Ocean.
It is here, in the Hawaiian waters, that Manta rays, stingrays and eagle rays call home. The most common of these rays are the Hawaiian stingray (Dasyatis lata), also known as the broad or brown stingray. Although common, sightings of these rays are rare in the wild as they are relatively inactive during the day, lying half-buried in the silt or muddy bottom of the ocean floor. These animals are most commonly found in Ma’alaea Bay off of the island of Maui and Kaneohe Bay off of the island of Oahu in depths of 50 feet or greater. Like most stingrays, they are scavengers and feed off of crustaceans or other small bottom dwelling fish.
Hawaiian stingrays can reach up to five feet in width and have been recorded weighing as much as 123 lbs. They are olive to brown in color on the top and white underneath with a diamond-shaped disc and round snout. The length of its whip-like tail measures two times the width of its disc. Although they are non-aggressive by nature, they possess a serrated spine located on the upper surface near the base of the tail. This spine, or barb, lays flat against the tail over a neurotoxin producing venom gland. If the ray becomes threatened, it can bend its tail towards the head causing the barb to rise at an angle and impale anything located above it. In most cases the barb, made of dermal denticles, will break off in its victim leaving the ray defenseless until a new barb is regenerated.
All animals in the Maui Ocean Center are brought in from the waters surrounding the islands where they are maintained for up to two years. During my visit, I was able to observe four Hawaiian stingrays in the Open Ocean exhibit. This is the largest exhibit at the center containing 750,000 gallons of water and home, not only to stingrays, but also sharks and fish.
Diving in the tank with these amazing animals gave me the unique opportunity to observe their behavior. It was obvious these Hawaiian stingrays were acclimated to the occasional diver, as they did not pay much attention to me at first. They were aware of my presence, but did not shy away from me when I approached them resting at the bottom of the tank. As I pulled out a few pieces of food, the rays remained stationary and had no reservation eating directly out of my hand as long as the food was brought to them.
Overall, their behavior seemed like that of a casual tourist taking in the sights. They lazily swam the perimeter of their enclosure, occasionally resting on the bottom of the tank. Unlike the other animals in this exhibit, they frequently swam up to the large viewing glass or underwater walkway and skimmed its surface. This was a highlight for the guests viewing the tank as well as a point of interest to the stingrays. The four stingrays did not seem to oppose being next to each other (no aggressive behavior was noted), but also did not swim in a group or “fever” as many rays do.
About 30 minutes into the dive with no food in my possession, two of the stingrays became increasingly curious of me. Their passes became closer and closer until one finally swam directly towards me and rested at my knees. As I remained still, the stingray inched closer allowing me to reach out and touch its disc! The movements of the ray seemed gentle and deliberate as if evaluating my movements and actions. It raised the tip of its nose, or rostrum, and placed its disc over my hands and legs for a closer “look.” Stingrays, like sharks, possess a sixth sense as they are able to detect electrical pulses in the water using small pores called ampullae of Lorenzini. These pores are located around the rostrum (nose), bottom of disc and most densely around the mouth. Through physical contact of its mouth over my hands and legs, the stingray was able to increase its evaluation of me by assessing the beat of my pulse.
Sitting on the ground, connecting with the Hawaiian stingray is a unique experience. Stingrays continue to impress and fascinate me for their intelligence, social behavior and gentle disposition.