Marine Mammal Research Organisation - Part 2 - Whales
Set: Part No: ST011836
Set: CTO: ST011837
Set: FDC: ST011838
The Bahamas Marine Mammal Research Organisation (BMMRO) is a Bahamian non-profit organisation whose mission is to promote the conservation of marine mammals in The Bahamas through scientific research and educational outreach. Since 1991, BMMRO has been conducting small vessel surveys primarily around Abaco Island to document the occurrence, distribution and abundance of marine mammals in The Bahamas. The majority of species found here are deep diving toothed whales that inhabit the pelagic waters surrounding the shallow Bahama banks. Some migrate through The Bahamas, but many species are year-round residents, including some of the world’s least known whales. By photographing the pattern of natural nicks and scars on each animal’s dorsal fin or tail flukes, a technique known as photo-identification, we are able to keep track of individuals - gaining an understanding of their population demographics, reproductive success, and social structure. BMMRO’s field work has expanded over the past ten years to include larger vessel surveys in the Great Bahama Canyon, including at the US Navy’s Atlantic Test and Evaluation Center in Tongue of the Ocean, where use of tactical sonars potentially pose a risk for some species. This work has provided a wider picture of marine mammal distribution in the northern Bahamas and have aided in identifying important areas for deep-diving whales. Genetic studies and pollutant analyses have helped to identify stocks and will allow further investigation of the health of local populations. Through on-going partnerships with universities and oceanographic institutes, BMMRO has many new projects underway including the use of time-depth recording tags to investigate beaked whale foraging behavior and hexacopters to photograph whales to assess their health.
Short-finned pilot whales (Globicephala macrorhynchus) can grow to 18 feet in length and weigh over 5,000 pounds, with males being significantly larger than females. They have a bulbous forehead with no perceptible beak, a faint grey diagonal stripe behind each eye and a faint grey “saddle” behind and below the dorsal fin. The rest of their body dorsally is jet black, which prompted whalers to name them “blackfish”, a term that also includes three other species known from The Bahamas (melon-headed whales, pygmy killer whales and false killer whales). Pilot whales can readily be distinguished from the other blackfish species by the position of their large, broad-based dorsal fin, which is set quite far forward on their body. They live in matrilineal pods consisting of up to three generations of related females and their offspring. On calm days, they can be seen in tight groups lying abreast, resting at the surface for hours. Pilot whales are seen in The Bahamas year-round but are more common during the spring and summer months, and are not a resident species. Pilot whales found in The Bahamas appear to have large ranging patterns; pilot whales tagged in The Bahamas have travelled as far north as North Carolina suggesting they are part of the US southeast population.
Sperm whales (Physeter macrocephalus) have dark brown, wrinkled-looking skin and an enormous square-shaped head that comprises one third of their total body length. Males can attain a body length of 60 feet while females are considerably smaller, reaching 35-40 feet in length when mature. Their single blowhole on the left side of the head at the front causes a distinctive “blow” which angles to the left and forward. Sperm whales dive to great depths (>3,000 feet) for more than an hour at a time where they feed on large squid, their primary prey. When a sperm whale prepares to dive, it raises its massive tail, allowing researchers to photograph the distinctive pattern of notches in the trailing edge of the tail flukes to aid in monitoring individuals over time. Adult females form nursery groups which are long-term social units made up of related females that can be found in The Bahamas year-round. Some of these females have been repeatedly seen in The Bahamas over the past 20 years. Mature males frequent the islands only during the winter breeding season and spend the rest of the year feeding in more productive Arctic waters.
Blainville’s beaked whales (Mesoplodon densirostris) are found in all the world’s tropical and temperate waters and are one of the most common species seen near Sandy Point, Abaco, where BMMRO is based. These medium-sized whales reach 14-16 feet in length, are brownish-grey in color and have a spindle-shaped body that tapers at both ends. They have a small dorsal fin found almost two thirds of the way back along their body and a well-defined beak or snout, which usually breaks the water first as the whale surfaces to breathe. This species has only two teeth located in the lower jaw which erupt above the gum line in males when they become sexually mature, and are used as “tusks” during combat with other males and not for feeding purposes. Adult males look quite bizarre as they often have clusters of stalked barnacles growing on their protruding “tusks”. Older whales have numerous white oval scars caused by cookie cutter sharks and multiple paired linear scars caused by the “tusks” of their con-specifics. Each whale’s unique scarring pattern has allowed BMMRO to track individuals over multiple generations. This work has revealed that there are small, resident subpopulations of Blainville’s beaked whales inhabiting the deep submarine canyons in The Bahamas. This unprecedented long-term study of a
deep-diving, cryptic whale is recognized globally for its importance in increasing knowledge of the natural life history of this species.
Dwarf sperm whales (Kogia sima) are the most common marine mammal seen in the oceanic waters in The Bahamas. Adults reach only 8-9 feet in length, and the dorsal fin is set mid-way down the body and is falcate or triangular in shape, so they can easily be confused with dolphins at a distance. These small whales are often found solitary or in small groups, and have adapted numerous ways to avoid predators such as killer whales. They have counter shading, being dark grey dorsally and white on the underside making it more difficult to see them from the surface or from below. They also have a white line of pigmentation on each side behind the head, known as a false gill, making them look like a shark. When threatened, they expel ink which they have ingested from squid, their primary prey, creating a dark cloud allowing them to escape. Their behavior while at the surface is very cryptic, and they are most typically seen logging, or lying motionless. When a vessel approaches them, they dive and swim away, making them very difficult to observe.
FDC Photograph: BMMRO
Designer: Andrew Robinson
Printer: Cartor Security Printing
Process: Stochastic Lithography
Perforation: 13 ¼ x 13 ½ per 2cms
Stamp size: 28 x 42mm
Sheet Layout: 20 (2 x 10)
Release Date: 10 April 2017
Production Co-ordination: Creative Direction (Worldwide) Ltd