Why are no Tuemmler endangered

Federal Agency for Nature Conservation

Bottlenose dolphins are particularly endangered not only in the North Sea by disruptions from shipping and other human activities, as well as by creeping poisoning. It is not considered endangered worldwide, but the number of areas with declining populations is increasing. In otherwise optimal habitats, the species seems to be less sensitive to underwater noise, as in other parts of the world industrial harbors are also part of the regular annual habitat. However, environmental toxins there are likely to endanger reproduction and health all the more.

The loss of habitat associated with heavy shipping traffic and construction of the coast could have been responsible for the extinction of the bottlenose dolphin in the southeastern North Sea. For example, the well-known bottlenose dolphins in Marsdiep in the Netherlands (from January to May between Den Helder and Texel) stayed away after previous dikes had caused the spring migration of the local “Zuyder Zee herring” to extinguish. At the same time, the annual number of strandings in the Netherlands also fell to zero (Camphuysen et al. 2006).

  • A reduction in food fish, in particular herring, can deprive the bottlenose dolphin of its livelihood locally - and presumably also supraregional - as the Dutch example shows.
  • In addition, bottlenose dolphins can be “caught” in fishing nets and perish in them, which is a major problem, at least on the US east coast.
  • The embankment of estuaries and natural rivers and their tributaries as well as other hydraulic engineering measures have led to extensive habitat destruction in the German Bight.
  • The introduction of heavy metals and long-lived organic poisons, such as polychlorinated biphenyls (PCB) and much more, lead to a constantly increasing accumulation, e.g. in the fatty tissue of the relatively long-lived bottlenose dolphins, and can lead to reduced reproductive success and weakened immune defense.
  • Heavy shipping, such as in the southern German Bight, leads to a constant burden of constant disturbances with various disadvantages also for the social structure and, as a result, for reproductive success.

Overview of the status of Art

Habitats DirectiveII, IV
Red List Germany (Meinig et al. 2020)0 (extinct, ca.1970)
Red list worldwide (www.iucnredlist.org/initiatives/europe)DD (insufficient data)
Accountability (Meinig et al. 2020)General accountability