Maui #12 -- Dolphins and Flying Fish

Spinner Dolphin in Maui

This my final blog on my two trips to Maui and I am covering a special treat. In previous trips to Hawai’i, I have seen dolphins, by never as many and as close as we experienced on this trip. Among our whale watches, three featured good encounters with two types of dolphins: Spinner and Pacific Bottlenose.

Spinner Dolphins

The Spinner Dolphin is a relatively small dolphin found in offshore tropical waters around the world. The ones we saw were, to be more precise, Gray's or Hawai’ian Spinner Dolphins.

Spinner Dolphin off the bow of the whale-watch boat

This delightful creature is known for its acrobatic displays in which it spins along its longitudinal axis as it leaps through the air. It is quite a treat to witness and a real thrill to capture it in a photo because they are wicked fast.

A big spin

Much smaller than the Bottlenose Dolphins I will talk about later, adult Spinner Dolphins are typically four to almost eight feet long with a body mass of 50-175 lbs. They have a very long snout, but, like in all whales and dolphins, the snout is not a functional nose; the nose has instead evolved into the blowhole on the top of their heads. As I discussed before, as toothed whales, dolphins have single blowholes.

Spinners have a single blowhole

The Spinner has a triangular dorsal fin that is less hooked than the Bottlenose. Its dorsal area is dark gray, the sides light gray and the underside pale gray or white. When the get excited, their bellies can turn pink, as is evidenced in some of the leaping ones I photographed.

The color pattern is evident here

Spinner Dolphins live in nearly all tropical and subtropical waters, primarily in coastal waters or near islands or banks. Some in the eastern tropical Pacific, however, do live far out at sea.

They eat mainly small fish, squid and shrimp, often diving up to almost 1,000 feet down to catch them. They feed cooperatively – swimming around the prey in a circle and sending a pair through the circle to make a catch.

These shots demonstrate how clear the waters in Maui are

Spinner Dolphins are preyed on by sharks, Orcas, False Killer Whales, Pygmy Killer Whales and Short-Finned Pilot Whales.

Underwater view

Seeing them so active on our whale-watching trips was extra special because they are actually primarily nocturnal, usually spending the daytime resting in shallow bays near deep water. At dusk, they travel offshore to feed.  

Jump

Spinner Dolphins of Hawai’i live in family groups, but also have associations with others beyond their groups, loosely changing affiliations as conditions dictate. It is common for pods to include around 200 dolphins, but some have had up to 1,000. Mothers and calves form strong social bonds. Like Humpback Whales, they are fairly promiscuous, without forming any long-term relationships with mates.  

Spin

Vocalizations of Spinner Dolphins include whistles, which may be used to organize the school, burst-pulse signals and echolocation clicks. 

When performing the breed's famous acrobatics, a Spinner Dolphin comes out of the waterfront first and twists its body as it rises into the air. When it reaches its maximum height, it falls back into the water, landing on its side. 

Dive

They may also make nose-outs, tail slaps, flips, head slaps, "salmon leaps," and side and back slaps.

Did you notice how pink this Spinner's tummy is as it jumps? That means they're happy.

I guess they really enjoy performing for an appreciative crowd. And, that crowd is probably their pod, not us silly humans oohing and aahing on a little raft.

Tens of thousands – probably half of all eastern Spinner Dolphins – were killed from the 1959 through 1980s by getting caught in purse seine fishing nets used for tuna fishing. 

Now, there are regulations limiting annual mortality and promulgating regulations for the safe release of captured dolphins. They have also been contaminated by pollutants such as DDT and PCBs.

We were so thrilled to see these frisky critters, especially the spinning ones off the Zodiac and the pod that swam directly under our snorkeling catamaran.

Oh, and did I mention we saw babies, too?

Mama and baby

Pacific Bottlenose Dolphins

We also saw some Pacific Bottlenose Dolphins and got some reasonably good video of them. I posted my video in the last post. 

Shot pulled from my video

Here is Caty’s video.

The ones we saw were part of the Pacific branch of Common Bottlenose Dolphins. The larger species group are the most familiar dolphins due to the wide exposure they receive in captivity in marine parks, movies and television programs (Flipper, anyone?). 

Flipper was a popular TV show from 1964-67

They are the largest species of the beaked dolphins and live in temperate and tropical oceans throughout the world, absent only from polar waters. Until recently, all Bottlenose Dolphins were considered as a single species, but now the Indo-Pacific Bottlenose Dolphin and Burrunan Dolphin have been split out. With considerable genetic variation among members of this species, even between neighboring populations, many experts believe additional species may be eventually recognized. For my purposes, I split the Pacific from the Atlantic, which I have seen in Florida.

Atlantic Bottlenose Dolphin photographed in Clearwater, Florida

Much bigger than the Spinner, the Bottlenose ranges from six and a half to 13 feet long and weighs between 330 and 1,430 lbs. Males are generally larger and heavier than females.  

The snout is quite short

Newborn calves are between two and half and four and a half feet long and weigh between 33 and 66 lbs. 

Dolphins have a short and well-defined snout that looks like an old-fashioned bottle, which is the source for their common name. Some explanations say a "gin bottle," but I am not sure how that is different.

Their necks are more flexible than other dolphins' because five of their seven vertebrae are not fused together as in other species.

Bottlenose Dolphins live in groups called pods that typically number about 15 individuals, but group size varies from pairs to more than 100 or even occasionally over 1,000 animals for short periods of time. The Bottlenose Dolphins we saw were in much smaller groups than the Spinners – probably no more than six.

Two Bottlenose Dolphins surface together

Their diet, like the Spinners’, consists mainly of eels, squid, shrimp and wide variety of fish. They do not chew their food, instead swallowing it whole. Dolphin groups often work as a team to harvest schools of fish, but they also hunt individually. Dolphins search for prey primarily using echolocation, which is a form of sonar. They emit clicking sounds and listen for the return echoes to determine the location and shape of nearby items, including potential prey. You can hear some clicking here:

Dolphins also use sound for communication, including squeaks emitted from the blowhole, whistles emitted from nasal sacs below the blowhole and sounds emitted through body language, such as leaping from the water and slapping their tails on the water. Their heads contain an oily substance that both acts as an acoustic lens and protects the brain case.

One of the dolphins we videoed seemed to lunge toward the boat; my video revealed it was chasing a fish.

Dolphin chasing a fish

The average life expectancy is about 17 years, but in captivity they have been known to live to up to 51 years old.

Some Bottlenose populations live close to the shore and others live offshore populations. Generally, offshore populations are larger, darker and have proportionally shorter fins and beaks. These characteristics protect it from predators and help retain heat. Plus, their blood chemistry is better suited to deep diving.

This is what you most frequently see on the surface

Coastal dolphins appear to adapt to warm, shallow waters with a smaller body and larger flippers, for maneuverability and heat dispersal. They can be found in harbors, bays, lagoons and estuaries.

Offshore populations can migrate up to 2,600 miles in a season, but inshore populations tend to move less. However, some inshore populations make long migrations in response to weather.

Movie Star Winter, Clearwater Marine Aquarium

The Bottlenose Dolphin has a bigger brain a human and has demonstrated high intelligence. In addition to being used in the entertainment business (against their wills, I assume), they have also been trained for military uses such as locating sea mines or detecting and marking enemy divers. 

In some areas, they cooperate with local fishermen by driving fish toward the fishermen and eating the fish that escape the fishermen's nets.

Swimming just below the surface

Swimming with dolphins is a popular tourist activity and, indeed, our girls have done it. Now, I no longer support this amusement.

Becca swimming with dolphins in 1999

 Dolphin hunting for food is still allowed in multiple countries, including Japan and dolphins are sometimes killed inadvertently as a bycatch of tuna fishing. They are also negatively affected by water pollution, especially oil spills.

View from the raft

Fun to See, But at What Cost?

We were thrilled to see so many dolphins, especially since we were not actually seeking them. But, recently, there have been criticisms about the number and frequency of dolphin-watching trips in Hawai’i. Efforts are being made both to educate the public and to minimize human impact on the dolphins.

Plunging down

Flying Fish

I mentioned earlier that we had seen some Flying Fish, but didn't really talk about them. Here's the lowdown.

While they don't fly in the same way as a bird does, Flying Fish sure look like they do. They leap out of water and use their long wing-like fins to glide over the surface of the water. They can "fly" for up to 40 seconds while traveling distances up to 1,300 feet. Their average flights are about 160 feet at about 40 mph. They normally glide about a foot above the water, but they can "fly" as high as 20 feet up.

Flying Fish off the boat's bow

At the end of a glide, they fold their pectoral fins to re-enter the water, or drop their tails into and push against the surface to lift for another glide, often changing direction.

A closer look

Flying Fish are commercially fished in Japan, Vietnam and China by gillnetting, and in Indonesia and India by dipnetting. In the Solomon Islands, they are caught while they are flying, using nets held from outrigger canoes. In Japanese cuisine, they are dried and used to flavor broth and their roe is used in sushi. 

As I mentioned, Flying Fish are a favorite treat of many seabirds, No wonder they move so fast

Goodbye Maui
That's it for my Maui posts. The two trips were both great. What fun!

I love Maui

Trip 1 date: January 31-February 8, 2019

Trip 2 date: February 25-March 2, 2019