April's featured species is the colonial Hydrozoan Velella velella, notable for its prolific presence during this time. FECDAS volunteers have reported numerous sightings of this species, which congregates in significant numbers on the ocean surface, particularly following storms or shifts in currents, often washing up on shore.

 
Figure 1. Velella velella observations. Observation uploaded to Minka’s platform. Loreto Rodriguez.

While commonly referred to as "sailboat jellyfish," these organisms are not classified as true jellyfish. They are colonial creatures composed of specialised individuals known as zooids, each dedicated to specific tasks like floating, feeding, and reproduction. The colony features a disk-shaped float resembling a sail, enabling navigation across the ocean surface propelled by wind currents. Beneath this float lies a transparent, polyp-shaped structure called a hydrocladium, housing the specialised individuals responsible for feeding and reproduction.

Throughout March and April, the Catalan Federation of Underwater Activities (FECDAS) undertook a series of initiatives as part of ANERIS, orchestrating a total of 13 actions. Among these endeavors were participatory surveys aimed at assessing marine biodiversity, primarily conducted through diving, except for one conducted using free diving, occurring on 3 March and 9 April, respectively.

Summary map of the activities in March and April.

Furthermore, dissemination activities took place during a video-sub competition hosted along the shores of Mataró. Participants were briefed about the ANERIS project, urging them to engage in biodiversity monitoring and report their findings through the MINKA platform. Over the past few months, 132 individuals have been educated and actively engaged in FECDAS’s activities, collectively providing 2,988 observations of marine biodiversity, all documented on the platform.

Biodiversity census dive at Platja d’Aro with DIVERS (20/04/2024)

The FECDAS team extends their gratitude to the diving clubs and centers that participated in these activities, particularly Blanes-sub, the VIMAR Vida Marina volunteer group, Unisub Estartit, La Sirena, Mateua Dive, DIVERS, SPAS MATARÓ, and the Centre d'Estudis Marins (CEM).

A full list of the organised activities is available in the Events section.