Blue Shark Monitoring Study in Cap de Creus

Project Objectives

• Raise awareness of the presence of blue sharks in Cap de Creus waters
• Describe the habitats and movement patterns of blue sharks in Cap de Creus waters
• Understand the population structure of blue sharks in Cap de Creus waters

Although the first outings in search of blue sharks in Cap de Creus took place in 2019, the monitoring study officially began in 2020.
In the 2020 season, 14 monitoring outings were made.
In the 2021 season, 18 outings were made.
In the 2022 season, 54 outings were made.
The project was fully funded by Sotamar Shark Tour (Divecreus S.L.).

In the 2023 season, 49 outings were made, funded 50% by Sotamar Shark Tour (Divecreus S.L.) and 50% by the General Directorate of Environmental Policies and Natural Environment from the Department of Climate Action, Food, and Rural Agenda of the Generalitat de Catalunya.

In the 2024 season, 53 outings were made. The study was funded 33% by Sotamar Shark Tour (Divecreus S.L.), 33% by the General Directorate of Environmental Policies and Natural Environment from the Department of Territory, Housing, and Ecological Transition of the Generalitat de Catalunya, and 33% by Forestal Catalana S.A. (Government of Catalonia).

With this study, we aim to:

• Review the legal status of the blue shark in Spain (IUCN has already classified it as critically endangered in the Mediterranean).
• Modify the ISRA’s to include areas crucial for the blue shark.
• Implement specific conservation measures for the blue shark, whether by protecting its habitat or certain zones, adopting effective fishery management measures and collaborating with the fishing sector.

Location

The Cap de Creus underwater canyon (Catalonia) is located about 3 km off the coast. It is 40 km long with a maximum depth of 1,400 m.

The study and sampling area for this project is the part of the canyon (and surroundings) closest to the Cap de Creus point.

Boat trips are carried out from Cadaqués (the closest town).

2024 Team

In 2024, the team consisted of:

• Carla Valdés (Veterinarian)
  Responsible for data collection
• Jordi Riera (Technical Director of Sotamar)
  Responsible for logistics and chief of operations
• Jordi Ruiz-Olmo (PhD in Biology)
  Responsible from the Department of Climate Action, Generalitat de Catalunya
• Elisabeth Salvador (Environmental Scientist)
  Responsible from Forestal Catalana, S.A. (Government of Catalonia)

2023 Team

In 2023, the team consisted of:

• Isa Lobato (Biologist)
  Responsible for data collection
• Jordi Riera (Technical Director of Sotamar)
  Responsible for logistics and chief of operations
• Jordi Ruiz-Olmo (PhD in Biology)
  Responsible from the Department of Climate Action, Generalitat de Catalunya

2022 Team

In 2022, the team consisted of:

• Isa Lobato (Biologist)
  Responsible for data collection
• Clara Calatayud (Biologist)
  Scientific Director of the study
• Jordi Riera (Technical Director of Sotamar)
  Responsible for logistics

Methodology

The technique used to search for pelagic sharks in open waters is based on combining five simultaneous operations from the boat.

These 5 operations are the preparation of "chum," the practice of "chumming," the deployment of the "chum box," the placement of bait, and the data collection.

Chum Preparation
A mixture of fish remains, blood, viscera, and other tissues with seawater is pressed into a "chum," created on board in barrels.

Chumming
The process of attracting sharks by continuously throwing chum into the water. The boat may move slowly, drift without the motor, or remain stationary with dynamic positioning via GPS. In any case, the "chum" will leave an olfactory trail that the sharks can follow by sensing the smell from a distance and/or depth, which will lead them to the boat. This entire operation may take several hours to either succeed or not.

Chum Box
Semifrozen fish scraps, viscera, and various tissues are placed inside a box, a perforated rigid buoy, or a washing machine drum. It is submerged, hanging from a buoy or the boat itself. The fish gradually defrosts, and its smell attracts the sharks, which have a highly developed sense of smell.

Bait
A piece of fish or squid tied to a rope (without a hook) to keep sharks near the boat. It is not used for feeding them.

Data Collection

Species identification: Observations are made from the boat or during immersion/snorkeling encounters. Data collected includes size (cm), sex (M/F), presence of parasites or hooks, and any other relevant observations.

Environmental data: Cloud cover, wind speed/direction, current, sea state, and water temperature are recorded. Sampling position (latitude/longitude) and the number of boats in the area, including whether they are professional or recreational fishers, are also noted.

Chum details: The type of fish used and the amount (in kg) is recorded, along with any changes to the chum box and times of changes.


Shark behavior: When bait is used, behavior is noted, and photos/videos are taken.

Results

The study results of the 2022 seaso n were presented as a scientific poster at the 4th World Shark Congress, SHARKS INTERNATIONAL, held at L'Oceanogràfic in Valencia from October 19 to 22, 2022.

Results of the 2023 and 2024 seasons will be published in scientific articles and made available in the Publications section once completed and reviewed.

PHOTOS

VIDEOS 2021

VIDEOS 2020