Ferries Project

Ferries, a means to studying cetaceans

The Strait of Gibraltar is the only point of connection between the Mediterranean Sea and the Atlantic Ocean and encompasses Spanish, Moroccan and British waters. The area is characterised by narrow passages, intense anthropogenic activities and the presence of resident cetacean populations. Up to seven species of cetaceans can be sighted, including the fin whale (Balaenoptera physalus), the sperm whale (Physeter macrocephalus), the killer whale (Orcinus orca), the pilot whale (Globicephala melas), the bottlenose dolphin (Tursiops truncatus), the striped dolphin (Stenella coeruleoalba) and the common dolphin (Delphinus delphis).

what is the ferries project?

It is a project to monitor cetaceans from ferries with the aim of gathering scientific knowledge of the distribution of these animals in the Strait of Gibraltar and improving their conservation strategies. The target species are the common dolphin, bottlenose dolphin, fin whale and sperm whale, which are under threat in the Mediterranean Sea, according to the IUCN.

It also aims to investigate current practices and provide guidelines for their improvement, as well as to establish guidelines for action in the presence of cetaceans, as some species, such as fin whales and sperm whales, are particularly affected by collisions with large vessels.

With the support of Fundació Balearia and in collaboration with researchers from the University of Cadiz, the project started in 2018 through the companies Marine Mammal Information, Research & Conservation (MMIRC) and Ecolocaliza, and since 2020 it has been under the management of the Nereide assotiation.

This project enables technical personnel to embark on Balearia ferries to carry out marine surveys in the Strait of Gibraltar, specifically on the Algeciras – Ceuta and Algeciras – Tangier Med routes. These are line transects during which information is collected on the cetaceans inhabiting these waters. For this purpose, shipments are made 2 to 4 times a month for surveillance purposes.

© Akris Photography | Cristina Otero Sabio

© Akris Photography | Cristina Otero Sabio


The methodology followed is that described by the Mediterranean Network – Fixed line transect using ferries as platform of observation monitoring protocol (Mediterranean Network – Fixed line transect using ferries as platform of observation monitoring protocol). Each census includes a return trip to the destination city and is carried out in sequence. Visual observation with/without binoculars is carried out during surveys to confirm the presence of cetaceans.

For each sighting, data such as species identification, estimated number of individuals, age class, behaviour, etc. are collected. The position of the ferry is obtained by GPS and the distance between the platform and the sighted individual/group is estimated. The number of observers or volunteers on board can vary between 1 and 2 per census, plus another expert responsible for the census.

The field work is complemented by training days in which the area and the animals that inhabit it, the conservationist research that has been carried out, and the importance of marine fauna in the ecosystems are explained. During these days, the aim is also to train volunteers so that they can collaborate with the project by boarding the ferries and identifying the different species of cetaceans that can be found.

“Ferries, a means to study cetaceans” is part of the PhD project on the integrated management of marine areas characterised by the presence of cetaceans, carried out under the supervision of researchers from the University of Cadiz and the University of Aveiro, in collaboration with the University of Victoria (Canada).

Results to date

Since the beginning of the project, up to 270 sightings of more than 5000 animals belonging to different cetacean species, among which common and striped dolphins predominate, have been recorded in a total of 119 hours and about 3850 km travelled during 60 surveys.


+ 5000 ANIMALS


+ 3850 KM


© Asociación Nereide

Advantages of ferry-based monitoring

© Asociación Nereide

For more information about the project or about upcoming training dates, please send an email to info@nereide.org directed to Alessia Scuderi.

With the support of