Most divers encounter southern stingrays (Dasyatis americana) buried in the sandy bottom during a dive in the open ocean. During our time on Bimini island in the Bahamas, we decided to snorkel around the shallow mangroves in search of juvenile lemon sharks. Mangroves are critical environments for juvenile fish and sharks because it acts as a nursery for many species. Protected from the predators in the open ocean these shallow waters with their massive root systems provide protection.
We didn’t find any sharks but we were surprised to see so many southern stingrays around the shallow mangroves. There is a relatively large population of great hammerhead sharks that inhabit these waters at this time of year. Because the main predator of these rays is the great hammerhead shark we wondered if they modified their behavior at this time of year to try to avoid these sharks.
The focus of our trip was to photograph the giant mantas (Manta birostris) at San Benedicto Island in the Revillagigedo Archipelago. These are the largest mantas in the world and can be more than 20 feet (6 meters) across and weigh up to 3,500 pounds (1600 kilograms). The dive site called “the Boiler” is a cleaning station for these mantas where fish remove parasites from their bodies. Consequently, this site provides the best opportunities to see and photograph these gentle giants.
The Revillagigedo Archipelago lies approximately 390 kilometers (240 miles) off the coast of Cabo San Lucas in Mexico. These Pacific islands are more commonly referred to as the Socorro Islands. Aboard the Southern Sport, we dove 3 of the 4 islands (Roca Partida, San Benedicto, and Socorro).
A color variant from the more common black and white manta is an all black or nearly all black manta. It is not a different species of Manta birostris. However, it is exciting when one showed up as it looks so different.
San Benedicto is the island for the giant mantas. They are used to divers and show no fear of people. They swim It seems a bit surreal, even a few weeks after our encounter with them, to have had huge mantas swim within a few meters of us.
The purpose of our dive was to photograph Horn sharks and we got lucky on our second dive around Danzante Island in the Loreto Bay National Marine Park, Sea of Cortez, Mexico. Thank you to Juan Carlos Reyes Valerio our dive master for finding these rather reclusive sharks. Although we found 3 different horn sharks, 2 were deep in crevices and they were impossible to photograph. However, it only takes one and this shark was out in the open apparently waiting to be photographed. Horn sharks are not strong swimmers and this shark is trying to tuck as close to the rocks as possible.
This area has more than sharks and we saw 3 different species of ray, two that stayed still long enough for us to photograph. The ocellated electric ray or bullseye electric ray (Diplobatis ommata) can generate a moderate electric charge for self-defence. The bullseye or ocellus on the back is very distinctive and is where it derives its name. It is a small ray reaching about 10 inches (25cm) in length.
The second ray we were able to photograph was the spotted round ray also known as the Cortez round ray (Urobatis maculatus). They have short tails compared to many other rays and reach a length of about 17 inches (45cm). This ray didn’t stick around for very long before it headed to deeper water.
A surprise for us to come across was the banded guitarfish (Zapteryx exasperata). We were not aware that there were a guitarfish species in the Sea of Cortez. This fish can reach up to 4 feet (1.25m) and has both dorsal fins of nearly identical size. Unfortunately, it had its head facing away from us partly going into a crevice.
From our perspective, Banded Houndsharks are the main attraction of the reef we spent 3 days diving on. Of course there is always other life on a reef. Three rays we were able to photograph were the Red Stingray, the Thornback Ray and the Japanese Butterfly Ray. The Banded Houndshark and the Red Stingray hang out together competing for the same food source. These two look like they are best buds!
Japanese Butterfly Ray
A couple of unusual fish that we came across were the Guitar Fish and the Asian Sheepheads Wrasse. Of course there are always the Moray Eels.
Asian Sheepshead Wrasse
If it wasn’t for the sharks we would have spent more time photographing the reef. The underwater strobes bring out some of the bright colours of the marine life.
Chiba Peninsula in Japan is home to numerous varieties of shark. Banded Houndsharks, seen in the video of our last post, are the most numerous in the location where we are diving. We have seen hundreds on most of our dives. Big Fish Expeditions has organized this trip and the local dive company we are diving with is Ito Diving Service Bommie (known as Bommies) and is owned by Kan Shiota. Kan has been indispensable assisting us on every dive. Here Kan is giving the dive briefing along with Kenji Ichimura. Kenji has been part of our group from the beginning and has acted as chauffeur, dive guide, and most important, our interpreter. Meals and menus would have been a challenge without him so thanks Kenji!
The dive boat behind us (photo below) is just a short 5-minute ride to the dive site. The gear gets packed up after the dive and is ready to go back to the shop. Amazing what you can store in these tiny pickup trucks!
Of course, the highlight of the trip is the Banded Houndsharks. There are literally hundreds of these beautiful sharks at this site. Although typically shy, they will come near you, if you stay in one place. Tricia, as you can see is making some new friends.
However, their generally shy and cautious nature can change in a moment when food is around. There can be a hundred in a feeding frenzy all jostling for position. It is a bit surreal to swim through them when this is going on but they are only interested in the food, not divers.
In amongst the Banded Houndsharks are curious & often pushy Red Stingrays who we felt a number of times brushing against our heads. It is interesting to see the vibrant yellow markings on the underside of their body. As Larry swims off to locate some more sharks I captured this picture.
Our trip to Isla Mujeres, Mexico to swim with whale sharks (Rhincodon typus) was all we hoped it would be. The visibility here is better than some other locations as whale sharks come to Isla Mujeres to feed on Bonito (tuna) eggs which are clear, unlike other areas in the world where they feed on plankton.
Although we were focussed on whale sharks (Rhincodon typus) it is not uncommon to find manta rays in the same areas. On our 3rd & 4th day we had fewer encounters with the whale sharks but found areas where there were also manta and mobula rays. We had some great encounters with these rays!
One of the photography techniques we would like to perfect is Over-Under such as this one. Over-Under photos are tricky as you need to take into account the lighting and focus of both below and above the water line.
Whale Shark Facts:
they are called the Gentle Giants for a good reason as they can grow to over 40′ in length & weigh up to 21.5 tons (47,000 lb)
they are filter feeders and feed mostly on plankton, copepods, krill, fish eggs as well as small crabs & fish
their life expectancy is 70 to 100 years
they reach sexual maturity at 30 years and give birth to live young
they prefer to stay near the surface but can dive down to 5000′
they have no natural predators and humans are their only threat to survival
their mouths can grow to over 4.5′ wide
they filter an average of 1,500 gallons of water every hour