Cogitationis Poenam Nemo Patitur

rhamphotheca:

Why Are So Many Dolphins Beaching Themselves

by Jennifer Viegas

From New England to Peru, an unprecedented number of dolphins have been beaching themselves in recent weeks, and experts are grappling as to why.

On Cape Cod alone, 177 short-beaked common dolphins have stranded and 124 have died, according to an Associated Press report. The report goes on to say that the total is nearly five times the average of 37 common dolphins that have stranded annually there during the last 12 years.

More than 200 dolphins have washed up dead on the beaches of Chiclayo, Peru, according to The Blaze. In that case, dead anchovies were also found. Since these small fish are prey, the dolphins may have become ill as a result of eating them, but the deaths remain a mystery.

Katie Moore, of the IFAW, and other experts have offered the following as possible reasons for the dolphin strandings:

1. This year’s unusually warm winter. As Discovery News recently reported, the unusually warm temperatures are affecting animal reproductive cycles, hibernation patterns and more. The change could also somehow be impacting dolphins.
2. Geography. Moore said the hooked shape of Cape Cod appears to be trapping the dolphins and confusing them. But the question still remains, why are the dolphins going in that direction in the first place?
3. Movement of prey. Climate cycles could be altering the course of fish and other dolphin prey, the AP report suggests. Dolphins following the prey could then become stranded. That might help to explain why both sardines and dolphins washed up in Peru.
4. Disease. This is an obvious reason, but workers at the IFAW are tagging and taking blood samples of the stranded animals, AP has reported. Researchers have also conducted necropsies on dead dolphins, and yet still there are no clear answers. A Congressional briefing was even held earlier this month in the push to resolve the problem.
5. Decompression. I would be curious to know if the dolphins have internal air bubbles that can cause decompression sickness, more commonly known as “the bends” in humans. That might seem far fetched, but scientists have determined that the blood and tissues of some deceased beaked whales stranded near naval sonar exercises are riddled with bubbles.

(read more: Live Science)     (photo: mikeledray | shutterstock)