Nature Today

Bultrugmigratie in de wateren rondom St. Maarten

19-MEI-2014 - Zeezoogdieren in de Nederlands Caribische wateren, van de kleinere dolfijnachtigen tot de grotere walvissen, hebben altijd op veel aandacht kunnen rekenen. Nog niet zo lang geleden is het proces gestart om de Exclusief Economische Zones (EEZ) rondom Saba, St. Eustatius en St. Maarten aan te wijzen als zeezoogdierreservaat. Toch is nog steeds weinig bekend over de exacte ligging van de migratieroutes van bijvoorbeeld de Bultrug, of waar deze walvissen die elk jaar van januari tot juni in de wateren van de noordelijke Kleine Antillen te vinden zijn naartoe migreren, of zelfs waarom ze naar deze wateren terugkeren.
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Bericht uitgegeven door Dutch Caribbean Nature Alliance (DCNA) [land] op [publicatiedatum]

Zeezoogdieren in de Nederlands Caribische wateren, van de kleinere dolfijnachtigen tot de grotere walvissen, hebben altijd op veel aandacht kunnen rekenen. Nog niet zo lang geleden is het proces gestart om de Exclusief Economische Zones (EEZ) rondom Saba, St. Eustatius en St. Maarten aan te wijzen als zeezoogdierreservaat. Toch is nog steeds weinig bekend over de exacte ligging van de migratieroutes van bijvoorbeeld de Bultrug, of waar deze walvissen die elk jaar van januari tot juni in de wateren van de noordelijke Kleine Antillen te vinden zijn naartoe migreren, of zelfs waarom ze naar deze wateren terugkeren. Andere soorten, zoals de Potvis, zijn ook elk jaar in deze wateren te vinden, maar of dit dezelfde individuen zijn als rondom Guadeloupe en Dominica gezien worden, is onduidelijk, evenals de vraag of potvissen hier hun jongen ter wereld brengen. Dit zijn slechts enkele van de vragen waar een tiendaagse wetenschappelijke expeditie, genaamd "Megara Project", antwoord op hoopt te vinden.

Lees verder in het Engels…

The marine mammals in Dutch Caribbean waters, from the smaller dolphin species to the larger Humpback Whales, have always received a lot of attention. Not so long ago the plan to designate the Exclusive Economic Zones (EEZ) around Saba, St. Eustatius and St. Maarten as a marine mammal sanctuary was set in motion. However, little is still known about the exact migratory routes species like the Humpback Whale use, or where these whales that frequent the waters of the northern Lesser Antilles from January to June migrate to, or even why they come to our waters. Other species, like the Sperm Whale, also frequent our waters, but are they the same individuals that are seen in Guadeloupe and Dominica? And are these waters also used as a nursery by Sperm Whales? These are some of the questions a ten-day scientific mission baptised “Megara Project” hopes to answer.

Humpback Whale mother with calf spotted in the waters around Saint-Martin (photo: Megara Project)

In 2008, the Regional Activity Centre of the Specially Protected Areas and Wildlife Protocol (SPAW-RAC) adopted a Marine Mammal Action Plan at their Conference of Parties, which recommends the implementation of a cooperative strategy for conservation and management of marine mammals in the Caribbean. The aim of this plan is to facilitate the management of marine mammal migration corridors and protected areas for marine wildlife populations common to several countries.

At the Second International Conference on Marine Mammal Protected Areas (ICMMPA) in 2011, the Dominican Republic, France for the Agoa Sanctuary, covering Guadeloupe, Martinique, Saint-Martin and Saint-Barthélemy, the Netherlands for the Dutch Caribbean islands, and the U.S.A. for the Stellwagen Bank Sanctuary, demonstrated their commitment to this initiative, by establishing “twinning” partnerships. In 2012 regional parties adopted a standardised scientific protocol on observation and identification of marine mammals in the EEZ of the French Antillean islands, the Dutch Caribbean islands and the British island of Anguilla. The sanctuaries of these collaborating governments together make up an enormous area designated for the conservation and protection of marine mammals.

Humpback Whale on the Stellwagen Bank (photo: Kai Wulf)

The first phase of the "Megara Project" took place between 24 March and 3 April 2014 in the waters of Saint-Martin, Saint-Barthélemy and Anguilla. The St. Maarten Nature Foundation joined La Résèrve Naturelle de Saint-Martin, the conservation organisation for the Agoa Sanctuary, and its marine conservation partners for the duration of the project. Argos marine transmitters were implanted into the fatty tissue of seven Humpback Whales which will allow scientists to follow their journey via satellite tracking. Led by Mads Peter Heide-Jørgenson of the Greenland Institute of Natural Resources, the project also included taking skin samples of the tagged Humpback Whales for DNA analysis. These samples will be analysed by Dr. Per J. Palsbøll at the Dutch University of Groningen to determine the sex and origin of each individual. The samples will be compared to a database of over 8,500 samples collected from animals in the Northern Atlantic. This may help to resolve speculation within the scientific community that local Humpback Whales migrate to Greenland or the coast of Norway.

The project also includes an exciting educational component. The deployed satellite tags transmit real-time information on their location via satellites, so the public can follow the migratory path of the whales live on the internet. At the time of writing, one Humpback Whale is travelling in northeastern direction towards the open Atlantic Ocean, one is travelling in northwestern direction towards Florida and one is currently residing in Barbudan waters. The remaining four stopped transmitting several days after deployment.

Geographical location of four Marine Mammal Sanctuaries in the northern Caribbean and western Atlantic (photo: Google Earth)

With the information from this project, the Nature Foundation and its partners will lobby for a whale sanctuary to be established in local waters. The research also suggests that whale-watching activities done under proper guidelines may be a beneficial activity and help to boost the economy of St. Maarten.

The Agoa Sanctuary covers the territorial waters and Exclusive Economic Zones of Guadeloupe, Martinique, Saint-Martin and Saint-Barthélemy and is a vast 138,000 km2. It was established in 2010 to reinforce the protection of emblematic yet threatened cetaceans, to sustainably manage their habitats and to ensure that they are considered in the development of human activities.
The Sanctuary for the Marine Mammals of the Dominican Republic was established in its current form in 1996 and measures around 25,000 km2. It encompasses not only the shallower calving and breeding grounds of the Silver Bank, Navidad Bank and Samana Bay, but also all of the deeper ocean waters between, which are heavily travelled migration routes for whales headed to other parts of the Caribbean.
The Stellwagen Bank National Marine Sanctuary was established by US Congress in 1992. Measuring over 2,180 km2, the area is heavily used by maritime shipping and as a migratory route for several whale species. Close monitoring of marine mammals is necessary to prevent ship strikes and net entanglement and consists of visual and acoustic monitoring and tagging whales to better understand their behaviour in the sanctuary and nearby waters.
The Dutch Caribbean Marine Mammal Sanctuary will be officially established later this year. It encompasses the Exclusive Economic Zones of Dutch Caribbean Windward Islands and measures roughly 22,000 km2. It includes the well-known Saba Bank, which takes up 10% of the total area. Whales visit the area frequently on their migratory routes and the Saba Bank is thought to be a calving area for Humpback Whales due to its relatively shallow depth compared to the surrounding waters.

Lees het hele artikel in BioNews.

Tekst: Tadzio Bervoets, Nature Foundation
Foto's: Megara Project; Kai Wulf, Saba Conservation Foundation
Kaart: Google Earth
Nederlandse inleiding: Paul Westerbeek, Dutch Caribbean Nature Alliance

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