The Orca season 2018

by Jörn Selling

Fotos: firmm

The killer whales are one of the undisputed highlights of all whale watching trips. They come to the Strait of Gibraltar especially in midsummer, when the big tunas swim back from spawning in the Mediterranean. Then the fish are pulled up by the fishermen with lines and hooks from a depth of 200 meters. When the worn out fish are brought to the surface, they are a seductively easy victim, which the killer whales have learned to take advantage of. Not all of them take their share from the fishermen. Some Orca pods stick to their old way of life. This is also the case among humans; when a new line of business emerges, not everyone rushes into it. Some will prefer to remain faithful to their familiar way of life.

The hope for the killer whales to appear was this summer unfortunately hardly fulfilled. From the end of June to the end of August we offered 69 three-hour trips, but found the killer whales only on 7 of them. That's a sighting probability of only 10%! 2005 was also a poor Orca year, with a probability of only 18%. On an annual average, we see the orcas on 50% of the three-hour trips, so it's like tossing a coin. A risk many are willing to take. This is considerably less than the over 90 percent probability of other whales being sighted during the two-hour trips. But there have also been above-average Orca years, such as 2011 and 2016, with a sighting probability of more than 70% (see figure 2).

Orca tours in blue, the ones crowned with success in orangeResulting probability of sightings

So what we've experienced this year is unusual, but not extraordinary. We can only speculate about the causes, they could be both, either natural or human. The fact that we can even find the orcas in a limited marine area during the high season has to do with us humans from the very beginning. If the tuna fishery didn't exist, the killer whales wouldn't be there because there still would be enough fish left. The Strait of Gibraltar is marked by us humans in such a way that our influence must always be taken into consideration. These include defensive measures by fishermen who are not happy about the orcas. In 2004 it was the last time shots were heard, but grappling hooks and stones are still used to scare off the killer whales. Rumours of fishermen carrying firearms continue to circulate.

Among the natural causes, the fluctuation in the migratory behaviour of the tunas could be named above all. Perhaps there are years with enough migrating fish, so the orcas would rather hunt on their own than run the risk of being attacked by the fishermen. Moving between the lines can also cost a pectoral fin. That happened to Lucia, whom we didn’t see this year. Maybe it even cost her calf the life.

Photos of the last encounter on the 16th of August

Camorro Female Calf playing

The killer whales belong to the most intelligent animals, together with apes and us. They certainly weigh carefully whether it is worth taking a certain risk. If pinching tuna from the fishermen were risk free we would probably find the orcas there much more often. So there must be a catch, except for the already dangerous fishhook!

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