Lior Shek, Zoyt - news agency for science and the environment
The North Atlantic osprey, one of the largest mammals in the world, was recently defined as a species that is "one step away from total extinction". What caused this situation and what can be done, also in our Mediterranean Sea, to protect marine mammals?
One of the largest mammals in the world, a whale of the North Atlantic oblaine species (black oblaine - Eubalaena glacialis), rose this month Officially From the "endangered" category to the "severely endangered" category On the Red List of the International Union for Conservation of Nature (IUCN). This is the last step before moving to the "extinct species" category.
in an annual report של NARWC organization ((North Atlantic Right Whale Consortium) As of the end of 2018, it was estimated that the number of adult whales of this species living in the wild is lower than 250, out of a total number of 409 individuals.
For the past 300 years, the population of the Black Balena has been suffering from intensive hunting for commercial purposes, which has caused a significant reduction in the number of individuals to the point of extinction. The whale is a particularly attractive and easy target for hunting, because it consumes its food by slowly filtering plankton on the surface of the water. In addition, after it is killed, its body floats on the surface of the water thanks to a thick layer of fat - hence its foreign name, "Right Whale", a "good" target for hunting.
Although, in recent decades, whaling has been completely prohibited, except for the granting of individual permits to local fishermen in countries such as Iceland and Greenland, but despite this, the baleen populations continue to disappear, and conservationists, environmentalists and marine biologists work with the help of a combination of innovative technologies and various scientific tools to monitor the remaining population, while Identification and analysis of all the risks that cause a sharp increase in mortality.
When a man and a whale meet
Today, the main causes of mortality and the threats that the black whale populations face, stem from human-whale encounters: Current tracking data They show that out of 30 cases of serious injury or death resulting from human-whale encounters between 2016-2012, 26 were caused by whale entanglement in commercial fishing gear. In just the last few days, for example, A record of a sperm whale has been published that a fishing net was wrapped around its tail near the coast of Italy in the Mediterranean Sea.
High-resolution underwater photographs revealed About 83 percent of the black whiting population suffers from external wounds caused by repeated entanglements in fishing gear. In cases where entanglement in nets or fishing lines does not cause a direct impairment of function, instead a long-term effect such as a decrease in fertility is caused, the result of which is a significant reduction of the individual's and the population's potential to recover.
Additionally, In 2012 a study was published of a group of researchers from the US National Oceanic and Atmospheric Administration (NOAA) who showed that underwater noise, caused by the passage of large vessels such as cargo ships and tankers, makes it difficult for individuals to communicate with each other during breeding and searching for food sources when 63-67 percent of the calls of black puffins Lost in the noise. In addition, the remaining population suffers from a limited genetic diversity that harms the reproduction and restoration potential.
These problems have solutions that can be implemented. for example, A study published in 2018 by NOAA on marine mammal populations in the Atlantic Ocean and Gulf of Mexico Show that the number of deaths caused per year as a result of boating accidents Decreased from 2 to 0.4 whales, this is due to changes in sailing routes and their diversion from areas where there are a relatively large number of whales.
Dealing with climate change
Climate change, which is also obviously related to human activity, has intensified and exacerbated the threats faced by the whale population in the North Atlantic Ocean. The rise in seawater temperature has pushed the whales' main food sources further north, to areas where the whales are exposed to human encounters. In 2017, for example, 12 whales died in the Gulf of St. Lawrence region of the North Atlantic Ocean as a result of entanglement in fishing gear and collisions with ships.
Therefore, specific areas that are a focal point for foraging, mating and spawning, which have been significantly reduced as a result of global warming have been defined in the annual report of the NARWC organization as "critical habitat areas", which are of utmost importance in preserving and saving the species from extinction.
Low birth rate
Unfortunately, it is possible that the situation of the black whale, and of other species of whales, is even worse than that presented by the latest studies, this is because the populations have a limited number of individuals, and are on the verge of extinction, characterized by fertility problems and a decreasing birth rate. In order to maintain a functioning and vital population, there must be a minimum amount of individuals in order to create genetic diversity. Among the Black Balena, the birth rate is significantly lower than in previous years, evidence that raises questions about the real chances of the population to recover.
Scientists, environmental activists and nature conservationists hope that the unfortunate transition of the black baleen whales to the category of "severely endangered species" will help bring its dire situation to international recognition, raise awareness and mobilize additional necessary resources for the restoration of the black baleen population in the wild.
Threats in the Mediterranean as well
The waters of the Mediterranean are a habitat for many species of marine mammals: whales, among them the common whale, the gray whale, the common dolphin and the striped stella.
"There is a lot of information about species that move along the shores of Israel in the Mediterranean, such as the common bottlenose dolphinTursiops truncatus), or species that arrive in the eastern Mediterranean at regular intervals such as the common gray whale. However, species that stay in deep water are more difficult to monitor and there is not much information about them, mainly because in these areas it is more expensive to carry out surveys", says Dr. Aviad Sheinin, from the Maurice Kahn Marine Research Station, Charni School of Marine Sciences, Haifa University.
According to Sheinin, the threats that the native species face are similar to the threats to marine mammals around the world. "The level of risk and exposure of marine mammal species to fishing equipment increases the closer the distribution of the species is to the coastal area. As you go deeper, the risk of entanglement with fishing gear gradually decreases. In addition, water pollution also affects coastal marine mammals such as the common dolphin (Delphinus delphis) observed in recent years only south of the Tel Aviv line, the common dolphin (Tursiops truncatus) and the Mediterranean monk seal. There are global hazards, such as ship noise, but the risk varies according to certain regions."
Sheinin explains that dealing with all the threats is complex, because marine mammals are characterized by a cross-border living space. "The Mediterranean Sea is not a single entity, therefore, the degree of influence of fishing or noise regulations in the jurisdiction of one country is not always valid in the jurisdiction of a neighboring country. In addition, threats such as noise have not yet been defined as a hazard or pollution as a result of difficulty in defining offensive noise thresholds for the indicator species (the use of indicator species is a tool for examining changes in biological diversity in order to take quick action against species loss).
Today, among the marine mammals in the Mediterranean Sea, there are several species that appear on the IUCN Red List: the common dolphin is in danger of extinction and the common dolphin is defined as "vulnerable". The monk seal populations are few, but they are recovering in the area of Greece and Turkey, therefore, the species recently changed its definition from "severely endangered" to "endangered". However, the deep sea species such as the striped Stenella dolphin are not properly monitored and there is not enough information about them in Israel.
In the document The action plan for marine mammals in Israel Published by Makhmalyi in 2017, they explain that "human activity dramatically affects marine biodiversity and in order to prevent irreversible damage to marine ecosystems, in-depth institutional and public responsibility is required. Marine mammals are considered 'symbolic species for global conservation' and their concern is important and legitimate, since most of the many human factors that threaten them are expected to increase in the future. In the waters of the Mediterranean Sea, several marine populations in severe distress are defined in the IUCN Red List as threatened populations. Failure to stop their depletion will be a cry for generations."
"In the last 20 years, a lot of effort has been made in Israel to cover marine mammals in the Mediterranean Sea. We aspire to continue conducting surveys for the purpose of collecting information that is currently missing on the deep sea mammal species and their representation on the IUCN Red List", concludes Sheinin.
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