Author: Eleonora Barbaccia

Which eDNA filters were used?

The results obtained from the previous field sampling campaign, identified 10 L water samples and Smith-Root filters as the most practical option for eDNA cetacean research (Rodriguez et al., 2025).

Therefore, the 2024 season aimed to collect two Smith-Root filters (1.2 µm) for each encounter (2 x 10 L) and Waterra filters (0.45 µm) for population genetic analysis (2 x 30 L).

Italy Sampling Protocol 2024

Italy Sampling Protocol 2024

How many litres of water did you have to collect?

For each encounter, we collected 80 L of seawater, of which 2 × 10 L were subsequently filtered with Smith-Root (SR) filters and 2 × 30 L with Waterra (WAT) filters.

Which species were you targeting and why?

In 2024, the Italian fieldwork focused mainly on single individuals of large cetaceans, in particular sperm whales (Physeter macrocephalus) and fin whales (Balaenoptera physalus), as well as the most frequently sighted dolphin species.

Results

During the 2024 sampling campaign in the Ligurian Sea, a  total of 61 SR (57 filters + 4 blank controls) and 22 WAT (20 filters + 2 blank controls) collected from 31 encounters (individuals and/or groups) belonging to 7 cetacean species, among which were elusive and rare ones:

10 sperm whales (Physeter macrocephalus), 10 fin whales (Balaenoptera physalus), 5 striped dolphins (Stenella coeruleoalba), 1 bottlenose dolphin (Tursiops truncatus), 3 long-finned pilot whales (Globicephala melas), 1 Risso’s dolphin (Grampus griseus) and Cuvier's beaked whale (Ziphius cavirostris).

Fin whale (Balaenoptera physalus)

Fin whale (Balaenoptera physalus)

Were you working with citizen scientists? If so, were they interested in eWHALE?

On board Pelagos, the Tethys Research Institute’s research vessel, most citizen scientists were very interested in learning about environmental DNA (eDNA) and the eWHALE project. While many participants were initially unfamiliar with eDNA, over the course of the week-long cruise, as they observed and discussed the sampling procedures and project goals, their knowledge and interest grew markedly, together with a stronger willingness to contribute to marine conservation.

Mario Gabualdi & Eleonora Barbaccia

Mario Gabualdi & Eleonora Barbaccia

What was the most interesting thing that happened in the field?

During the 2024 season, for two consecutive days we had the opportunity to sight and sample Cuvier’s beaked whales (Ziphius cavirostris), a species that is generally very rare to encounter in our study area as it usually occurs on the other side of the Pelagos Sanctuary. This group of three individuals made us extremely happy and, for most of us, it was our first ever encounter with this species.

Which eDNA filters were used?

During the 2024 field season, we used Smith-Root eDNA filter cartridges with a pore size of 1.2 µm. For each whale encounter, we aimed to collect two replicate samples, filtering up to 10 L of seawater per replicate (2 × 10 L) with a maximum filtration time of 45 minutes for each. The sampling strategy was designed to obtain at least one eDNA sample per week throughout the season.

Iceland Sampling Protocol 2024

Iceland Sampling Protocol 2024

Which species were you targeting and why?

In 2024, fieldwork in Skjálfandi Bay (Iceland) focused mainly on humpback whales (Megaptera novaeangliae), the most frequently observed baleen whale in the area, which are regularly present in the bay from early spring to late autumn (approximately March–November). Sampling also opportunistically included blue whales (Balaenoptera musculus), which migrate through Skjálfandi Bay in spring and early summer, with most sightings typically occurring between April and June.

Results

A total of 98 samples were collected from fluke prints using Smith-Root filters in Iceland, onboard North Sailing whale watching boats and citizen science weekly tours. These included 9 field controls, 85 samples from humpback whales, and 4 from blue whales, collected between April and November. Two replicates were collected for each sample, with filtration volumes per replicate ranging from 4.5 to 10 L, limited by a maximum filtration time of 45 minutes.

Which was the research focus?

The objective of the Italian team during the 2023 field data collection period (19/07/2023 - 05/10/2023) was to collect varying water volumes (2, 5, 10 litres) for the purpose of investigating the minimum quantity of water required to locate eDNA traces inside.

Which eDNA filters were used?

The eDNA filters which were used during the first sampling campaign of eWHALE project in the Med Sea were: Sylphium (0.8 µm) and Smith-Root (1.2 µm).

How many litres of water did you have to collect?

For each encounter 20 L of water were collected, from which 2 litres, 5 litres and 10 litres were subsequently filtered with SR or SYL.

Italian sampling protocol 2023

Italian sampling protocol 2023

Which other species are possible to encounter in the study area?

In addition to cetacean’s species, other megafauna are also likely to be found in the Pelagos, including sea turtles (Caretta caretta), sunfish (Mola mola), mobula (Mobula mobular), and seabirds.

Where did you go sampling?

The sampling campaign was carried out in the Pelagos Marine Protected Area, a Special Marine Protected Area established on 25 November 1999 for the protection of marine mammals in the Mediterranean Sea, covering some 90,000 km² in the north-west Mediterranean between Italy, France and the island of Sardinia, including Corsica and the Tuscan archipelago.

How were the weather/sea conditions?

During the summer in the Pelagos Sanctuary, the weather is usually ideal for research cruises and data collection. Only on a few occasions during the course of the season can rough seas and storms occur, and on these occasions, the daily sea trip must be cancelled.

Pelagos Sanctuary Map

Pelagos Sanctuary Map

Results

At the end of the first sampling campaign, we totalized 27 Sylphium + 3 of controls and 27 Smith-Root  + 3 of controls, resulting in 60 filters.

The target species of Italy in 2023 was the sperm whale, but we also managed to sample the most common ones, obtaining sampled from 22 encounters (individuals and/or groups of individuals) of 6 different cetacean species, including: 7 sperm whales, 6 fin whales, 2 striped dolphins, 2 bottlenose dolphins, 3 long-finned pilot whales and 2 Risso's dolphins.

Were you working with citizen scientists? If so, were they interested in eWHALE?

On board Pelagos (the Tethys Research Institute research vessel), most of the citizen scientists were very interested in learning about the ecology of Mediterranean marine mammals and the eWHALE project. As in the other two locations, most of the whale watching customers were unfamiliar with environmental DNA, but by the end of the week-long cruise, they had significantly increased their knowledge by being able to observe and learn about the whole process.

What was the best part of fieldwork?

Apart from meeting marine mammals, which is always an unforgettable experience, the best part of this job is being in contact with people who are passionate and willing to learn more about the ecology and conservation of these magnificent species.

What was the most interesting thing that happened in the field?

During one of the sightings, a very curious sperm whale approached the bow of the boat, stuck its head out of the water, and looked at us intently. It was a wonderful feeling and an unforgettable experience.

Citizen scientists learning about the eDNA sampling process on board Pelagos

Citizen scientists learning about the eDNA sampling process on board Pelagos