Whale and dolphin species off Pico

Where these numbers come from

Every count on these pages comes from OBIS, the Ocean Biodiversity Information System, an open database that pools species occurrence records from research surveys, monitoring programmes and other contributors. Each figure is the answer to one query: one species, inside a fixed box of sea around Pico that also takes in the channel to Faial, which the boats from Madalena work. The query is linked beside each figure, so anyone can run it again and get the same answer, or a newer one.

What a record is, and is not

A record is one logged observation of a species at a place and a time. It is not an animal: the same group seen from three boats on one morning can be three records, and a whale nobody saw is not in the data at all. It is not a probability either. Records are made by people on the water, and people are on the water mostly in the warmer months, so the counts follow boats as much as they follow whales. A quiet month can mean a quiet harbour as easily as an empty sea.

Read the counts as "when and how often this species has been logged here", and they are useful. Read them as "my chance of seeing one in May", and they will mislead you.

The five species covered

• Sperm whale: the most-recorded cetacean in these waters by a wide margin, and the only one of the five logged in every month of the year.
• Common dolphin: the most-recorded dolphin, logged from March to October.
• Fin whale: logged from March to September, with May the busiest month.
• Blue whale: logged from March to July, and almost entirely between March and June.
• Orca: rare in the data, with records scattered across spring and early summer.

The season calendar sets these side by side with six more species (sei whale, short-finned pilot whale, and the bottlenose, Risso's, Atlantic spotted and striped dolphins), month by month, with the query behind every row.

What this section does not tell you

Body size, weight, diving depth and the share of trips that see a given species are absent. None of them has been checked against a primary source here, so they are left out rather than approximated. For the rules a boat works to around all of these animals, and the licensed operators who run trips, see whale watching on Pico.