Bernardo Nascimento: "Whales play a crucial role in marine ecosystems"
What is a whale? Who are their close relatives? Are there different types of whales?
Whales are large marine mammals that live in the ocean and belong to a group of animals called cetaceans. Cetaceans include animals such as dolphins, and according to evolutionists, they evolved from a land-dwelling mammal. There are two types of whales: those without teeth, also known as baleen whales (e.g., humpback whales), and toothed whales (e.g., sperm whales).
Whales play a crucial role in marine ecosystems. Could you explain their importance and their impact on the balance of the ocean environment?
Whales are essential contributors to marine ecosystems. Their excrement serves as a vital food source for phytoplankton, a type of "micro-plant" that drifts with ocean currents. Phytoplankton captures about forty percent of all carbon dioxide produced and generates half of the oxygen in the atmosphere.
Unlike large land mammals that release significant amounts of carbon dioxide into the air when they decompose, whales sink to the ocean floor when they die, sequestering large amounts of carbon for centuries. The ocean creates a layer that prevents this carbon dioxide from easily reaching the atmosphere. Over their lifetime, a whale captures the same amount of carbon as thousands of trees. In addition to their critical role in maintaining ecosystem balance as top predators, a healthy whale population at sea strengthens resilience against climate change.
Mauritius seems to be a prime location for whale watching. What factors attract whales to the waters around Mauritius, particularly in the Indian Ocean?
Like most animals, whales move based on two main motivations: food and reproduction. Most whale species feed in cold polar regions, where food is more abundant, and migrate to warmer waters to breed. Warmer waters typically have less available food. Experts mention three main reasons for these migrations: (1) their calves can grow faster in warm waters while nursing; (2) they face fewer significant predators such as orcas; and (3) whales shed their skin when they move to warmer areas, which is important for their overall health. Mauritius has warm waters, which is likely why some whales come to this region. Some species may stay in the area year-round. One example is female sperm whales and juveniles. Massive males, which can reach up to 18 meters, only come to the region to mate.
In recent years, have there been any observed changes in whale behavior or migration patterns near Mauritius? If so, what could be the reasons for these changes?
The presence of whales and their migration patterns, beyond water temperature and food availability, can also be influenced by human activities such as pleasure boats or commercial shipping routes. As a non-expert in marine mammals, I am not aware of specific studies showing these changes, but I wouldn’t be surprised if they were happening. I want to emphasize that temperature changes (linked to global warming) and food availability (impacted by fishing activities) are also driven by human activities, so ultimately, we can have a significant impact on whale populations in the region.
How does the presence of whales contribute to the local economy and tourism in Mauritius? Are there conservation efforts in place to protect these magnificent marine creatures?
Whales are a major attraction for tourists, so they undoubtedly have an impact on the local tourism industry. Unfortunately, there aren’t enough enforcement measures to ensure regulations are followed. Some non-compliant behaviors have injured animals in the past, and if boat operators do not start changing their practices, they could jeopardize the sustainability of the activity, which some operators say is already at risk.
Could you share information about the different whale species commonly observed near Mauritius? Are there any rare or unique species that might be of particular interest to enthusiasts?
There are several species in Mauritius, but I would say the two most charismatic and easiest to spot are sperm whales and humpback whales. Seeing mother humpback whales with their calves or one of the small groups of female, juvenile, and calf sperm whales is magical. And you can see both species during the right season relatively close to shore. However, it is extremely important to be respectful when approaching whales, especially if you find mothers with calves, to avoid disturbing and stressing them.
Given the potential threats to whale populations worldwide, what initiatives or projects is Odysseo involved in to raise awareness and contribute to whale conservation in the Indian Ocean?
Odysseo is part of a project developed by Professor Christine Erbe, Director of the Centre for Marine Science and Technology (CMST) at Curtin University, Australia, which will collect important data for whale conservation in Mauritius. In short, CMST has installed three acoustic receivers around Mauritius that will collect sounds from human and animal activities for a year. The recorded sounds will then be analyzed to understand, among other things, the impact of human activities on certain whale populations that migrate and live in the waters around Mauritius.
Whale watching has become a popular activity. What responsible practices do you recommend for individuals and tour operators to ensure minimal disruption to whales and their natural habitat during excursions?
Whale watching is highly regulated in Mauritius, but enforcement is lacking, and unfortunately, most operators engage in practices that can be very dangerous for the animals. Two of the most disruptive behaviors are boats getting too close to the whales or, even worse, blocking their path and forcing them to change direction constantly. Regulations state that boats must remain within a zone with a radius of 100 to 200 meters from the nearest whale. More precisely, within 100 meters is prohibited, the 100-200 meter zone is a slow-speed area, and swimming with whales is illegal in Mauritius unless you have a special permit granted only for research purposes.
How can the public actively contribute to whale conservation and habitat protection? Are there any specific actions or campaigns you would recommend supporting?
I would say the easiest and most important action is to be well-informed about whale watching regulations and to ensure that any operator they choose is very cautious about not disturbing or harming the whales. Another simple action is to support organizations such as the Marine Megafauna Conservation Organization (MMCO), which works to protect these magnificent animals.