CavAlMar Project - Seahorses of Trafaria
The CavAlMar project is a partnership between Almada City Council, MARE and ISPA, with the aim of studying biodiversity along the riverside coast of the Almada region, with a special focus on seahorses. 
Known and appreciated all over the world, seahorses are small fish that are difficult to spot, even when they choose shallow coastal areas as their habitat. Imagine the amazement of Mário Rolim, now CavALMar's diving operations coordinator, when he first encountered them in the Almada area, between Trafaria and Alfeite.
“I saw long-nosed seahorses, Hippocampus guttulatus, and common seahorses, H. hippocampus. I also found seahorses (Syngnathus acus), which are from the same family, but differ in their elongated morphology and horizontal locomotion. They are also distributed throughout Almada's waterfront, with one of the most important populations in the municipality in Trafaria Bay,” said the MARE researcher in an interview with Sustentix.
After the discovery, dives began and censuses were carried out, recording the biodiversity of the area. “When we find a seahorse, we take the animal, photograph it, measure it, cut off a bit of its fin to take a DNA sample and then release it,” he explains.
The aim is to characterize the population of these animals, their habitat and the impact of marine litter, in order to define a conservation plan. Between September 2022 and July 2023, around 60 specimens were recorded. Gonçalo Silva stresses that these results are provisional and it is not yet known whether or not the population is stable, as it is subject to many threats such as marine litter, the collapse of pontoons that serve as their habitat, dredging, underwater noise and overfishing.
For the MARE researcher, the construction of the Trafaria fishing port could be an opportunity for conservation. “At the moment it's covered in garbage and diving there is even dangerous.” The APA has put out for public consultation a document relating to the Proposed Scope Definition (PDA) of the Environmental Impact Study (EIA) for the Trafaria Fishing Port project, in the town of Trafaria, in the municipality of Almada, but the project has stalled, despite the fact that various entities and fishermen have already given their opinion.
Gonçalo Silva stresses that it would be important for seahorses to be recognized, not least because they could be an attraction for the municipality, believing that nature can boost the economy of a given area.
Photographs by Mário Rolim