Report on Striped Dolphins (Stenella coeruleoalba)

In the Strait of Gibraltar, Striped Dolphins (Stenella coeruleoalba) are still quite numerous. We usually meet big pods in the second half of summer - towards August both group size and sighting probability increase. According to our records, most calves are born in May and August.

Position Gestreifte Delfine 1999–2015
Positions of Striped dolphins from 1999 to 2015

The probability of sighting and the number of animals increase towards August. At the end of the season, the Striped Dolphins also move in larger groups. There seemed to be two peaks of birth: We saw most newborns in May and August.

Occasionally we can see smaller tunas in the Strait of Gibraltar, following pods of Striped Dolphins. It is not known whether there are adult tunas swimming below at greater depth, as has been observed with Bottlenose Dolphins and yellowfin tunas in the Pacific. However, this remains a common argument among big game fishermen to drive with their extended hooked lines through the whales off Tarifa.

Keydata from annual reports

2009

  • Very few sightings, both in the Strait - and in the Bay of Gibraltar (with Algeciras)

2010

  • Sightings increased in the Strait, but decreased in the Bay of Gibraltar
  • Largest pod with 1000 animals in June

2011

  • Sightings of Striped Dolphins increase earlier towards the end of the summer season, compared to sightings of Common Dolphins
  • Largest pods of up to 100 animals in September (three months later than 2010)

2012

  • Sightings increase earlier towards the end of the season than those of Common Dolphins
  • Largest pods of 1000 animals in June and September
  • 150 sightings in total

2013

  • Sightings increase earlier towards the end of the summer season than those of Common Dolphins
  • Largest pod fo up to 1000 animals in July and September
  • 202 sightings in total, many more than 2012 (the lack of Pilot Whales had made it necessary to search for other cetaceans in a wider area)

2014

  • Sightings of larger pods mainly in July, August and September, as with the Common Dolphins
  • Largest number of calves at September 9th: 150, accompanied by 400 adults
  • 232 sightings in total

2015

  • Sightings of larger pods with more than 400 dolphins mainly during the second half of the summer season, as with the Common Dolphins
  • Largest four pods: up to 1.100 animals in July, August, September and October
  • 213 sightings in total

2016

  • Sightings of larger pods with 600 to 1100 dolphins mainly during the second half of the summer season starting end of June, as with the Common Dolphins
  • Largest pod of up to 1100 animals from June 26th to October 2nd
  • 255 sightings in total, many of larger pods

2017

  • Sightings of larger pods with 600 to 1100 dolphins mainly during the second half of the summer season starting end of July, as with the Common Dolphins, exept for two pods on April 14th and June 24th
  • 249 sightings, 5 of them in the Bay of Gibraltar
  • Still frequent at the Strait of Gibraltar
  • No newborn detected (very difficult to discover inside larger pods)

2018

  • Sightings of larger pods with 400 to 550 dolphins mainly during the second half of the summer season starting end of July, as with the Common Dolphins, exept for two pods on May 8th and May 21st
  • 219 sightings off Tarifa (no trips into the Bay of Gibraltar)
  • Calves throughout the whole season, most of them in July and August
  • Two newborn on August 17th

For firmm reports sorted by years (in German) check out firmm-education.