Ria Formosa seahorse population shows signs of recovery
Photo: João Rodrigues-Chimaera Visuals

Ria Formosa seahorse population shows signs of recovery

Conservation efforts to save Ria Formosa’s endangered seahorse population are proving successful, with researchers reporting a “considerable increase” in numbers this year.

The good news came from Sea Science Centre (CCMar) researcher Jorge Palma during a boat trip on November 24, which was open to the press, to release several captive-bred specimens into the wild in Ria Formosa.

The short boat trip, from the University of Algarve’s Marine Centre of Ramalhete to one of the seahorse sanctuaries off the coast of Faro, involved much preparation, but the birth of seahorse babies along the way made it all the more memorable.

CCMar researcher Rui Santos went for a first dive to check if the conditions were right for their release, in a 100sqm area with seagrass.

“It is the ideal habitat and we do not want them to be dragged away when we open the transportation boxes,” Jorge Palma explained.

Although they were bred in captivity, the seahorses have the same “genetic heritage” as those already living in the wild.

Ria Formosa seahorse population shows signs of recovery
Photo: João Rodrigues-Chimaera Visuals

“Their grandparents came from Ria Formosa and were also released into the wild,” he explained.

As the situation stands now, researchers are focusing on releasing more short-snouted seahorses (Hippocampus hippocampus), which are less abundant in the wild than the long-snouted searhorses (Hippocampus guttulatus).

To put things into perspective, Jorge Palma said there is currently one short-snouted seahorse for every 10 long-snouted seahorses.

Populations are monitored on a daily basis and researchers are able to recognise each individual seahorse that has been released.

Ria Formosa seahorse population shows signs of recovery
Photo: Bruno Pires/Open Media

“All animals are previously photographed so that we can check if those in the sanctuaries are the ones that were released. Their spot patterns and the profile of their head varies,” the researcher explained, adding that these unique traits can be recognised by specialised software.

All these efforts have borne fruit, as the monitoring carried out since the last release in November 2021 shows that the Ria Formosa seahorse population has increased both in sanctuaries and in other areas of the estuary.

“While there was a decrease which reached 96% in 2021, the truth is that we are already seeing an increase, which we hope will continue,” Palma told reporters.

In the last 10 years, thousands of marine animals have been bred at the Marine Centre of Ramalhete.

“Breeding an animal in captivity is a conservation tool, it helps investigation, and it can also be a resource for aquaculture, although breeding seahorses is much more difficult than fish aimed for human consumption,” Palma explained.

“Seahorses are already miniature adults when they are born,” he said, explaining that they have to eat the same amount as adults and that they need mostly natural food sources, mainly small crustaceans.

Ria Formosa seahorse population shows signs of recovery
Photo: Bruno Pires/Open Media

Indeed, researchers have been carrying out several projects to study their nutritional needs in order to ensure they get what is required to survive.

When Jorge Palma started studying the breeding of seahorses in captivity in 2007, the survival rate was zero. Today, it is between 50 and 60%.

What is particularly interesting is that researchers have found that seahorses are intrinsically dependent on their environment – in this case, Ria Formosa.

“Even if we provide them a good nutritional profile, if we feed them only with artificial rations that are devoid of enzymes and amino acids which they need to process their digestion, they do not grow or survive. They always need a fraction of natural food,” the researcher explained.

The difficulty of breeding these marine creatures is one of the reasons why CCMar is the only centre of its kind in Europe to breed them and deepen their studies on these species.

This dependence on their natural environment does pose some risks to their survival, as the environmental quality of Ria Formosa has changed due to the “pressure” it is under nowadays.

“There was a time when illegal fishing for Asian consumption directly impacted (seahorse) populations,” Palma said, adding that now the main problem is the “degradation” of their ecosystems.

Climate change is also playing a role, with abnormally high temperatures posing great risks to the local seahorse population.

“We get the food (for the seahorses) from lakes near Ramalhete. In July, when we had that brutal heatwave, the water temperature exceeded 30ºC, which for marine life is a very high temperature. Due to evaporation, salinity levels reached 52%.

“The oxygen diminished, and everything died. We were left with practically no food for the seahorses. To give you an idea, this area here is at 35.7%, which is the average salinity of Ria Formosa at this time of year,” the researcher said.

The proliferation of Caulerpa prolifera, a type of invasive green algae which has invaded the estuary, may also pose a risk to the local seahorse population.

“We want to understand if there is any impact on the availability of food for seahorses,” researcher Rui Santos explained.

Studies carried out so far have shown that seahorses eat a larger variety of organisms in seagrass than they do around this invasive species.

Removing the algae is an impossible task, researchers say, adding however that they are optimistic that the seahorses will adapt to the new environment.

“We just hope there will be enough variety of food around the Caulerpa,” Santos added.

Original article written by Bruno Filipe Pires for Barlavento newspaper