15.09.2026 – Columbus crabs

Published by Marlene Cabral on September 23, 2026

While the Christopher Columbus Festival is taking place on our neighboring island of Porto Santo, we came across the very crab he was the first to describe after discovering it in Sargassum seaweed. He considered the appearance of this crab a sure sign of land being nearby. Today, we know that the Columbus crab (Planes minutus) is a tiny pelagic crab that never goes ashore and reaches a size of only 1 to 1,7 cm. It inhabits a wide variety of substrates—ranging from all manner of floating debris in the open ocean to animals such as the loggerhead sea turtle.
We were able to examine the crabs’ tiny undersides and distinguish between males and females: males have a visible triangle on their abdomen, whereas on a female, we could identify the oval egg sac. The specimens we found were brownish, though the color can also lean towards yellow or red.

For those interested in learning more about crabs, here is a link to Paula’s 2019 blog post about “Light-footed Sallies” (rock crabs): https://blog.lobosonda.com/de/leichtfuessig/

On all our excursions today, we encountered bottlenose dolphins (Tursiops truncatus), and in the afternoon, we also spotted an ocean sunfish (Mola mola).

by Claudia Gomes

Sightings of the day

Ribeira Brava

09:00 Bottlenose dolphins

13:00 Bottlenose dolphins

Steno

09:30 Bottlenose dolphins

Stenella

13:30 Bottlenose dolphins, Sunfish