TYPES OF STRANDINGS

Types of Stranding Events:

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Stranding events - natural phenomena that have occurred for centuries and the mechanisms behind these events, in many instances, remain one of the great mysteries of the animal kingdom.

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Types of Stranding Events:

Mass strandings or unusual mortality events (UMEs) refer to simultaneous standings of two or more cetaceans of the same species, other than a mother and calf, and simultaneous strandings of two or more cetaceans from mixed species groups.

Generally mass strandings are associated with toothed whales, particularly pilot whales and beaked whales. Mass strandings may occur for a variety of reasons, among them, are behavioural tendencies in some species to follow a “leader”, extreme weather events and geomorphological distortion of echolocation signals due to shallow sloping topography, known as acoustical “dead zones”.

However, overall causes for strandings are often inconclusive and vary in explanatory power based upon the number of stranded individuals, the area of stranding, in addition to conspicuous anthropogenic implications (e.g. seismic surveys, pile driving, by-catch and ship-strikes).

Over a period of six weeks from the 3rd of August 2018 to the 12th of September 2018, 21 Cuvier's beaked whales (Ziphius cavirostris) were reported to the Observers App stranded along the Irish coastline from Co. Mayo to Co. Donegal and Co. Antrim.

Pilot whales mass stranding at Golden Bay, in New Zealand February 2021. Image by Louisa Hawkes/ Project Jonah.

Types of Stranding Events:

HOTLINE: +353 89 4625374.

DEAD STRANDED: Various stages of decomposition.

LIVE STRANDED: Alive but in a helpless position, for example one that has come ashore because it is ill, weak or disorientated.

MASS STRANDING: Mass stranding events include beachings alive or dead, of more than one individual of the same species over a short period of time.

UME’s - UNUSUAL MORTALITY EVENT: involve a mass stranding of mixed species over a short period of time.

One notable unusual mortality event (UME) resulted in more than 80 Cuvier's beaked whales stranded between Ireland, Iceland and Scotland, in addition to one sperm whale and one northern bottlenose whale in Iceland and another northern-bottlenose whale in Norway in August 2018.