Saving the Algarve’s seahorses

By: Bruno Filipe Pires

They were once endangered, but today the Ria Formosa seahorses are making a comeback

On a quiet autumn afternoon, a trip from the Ramalhate Marine Centre from the University of the Algarve to one of the seahorse sanctuaries (protected area) of Faro marked the special moment a number of these captive-bred animals were released into the wild.

But before releasing the seahorses into the Ria Formosa, Rui Santos, researcher and associate professor at the Centre for Marine Sciences (CCMAR), conducted a dive to check the conditions as it was vital to wait until the tide calmed down. It was also important that the animals gradually got used to the water temperature.

“This is the ideal habitat, but we don’t want them to be dragged away when we open the transport boxes,” explained researcher Jorge Palma before diving in. Because these animals were bred in captivity, the release had to fulfil “all the mandatory requirements needed for reintroducing them into the wild. They have the same genetic heritage as their grandparents came from the Ria Formosa and have also been released”.

These days, it makes more sense to release animals of the less abundant species, the Hippocampus hippocampus (short-snouted variety). In terms of proportion, there is one of these for every 10 Hippocampus guttulatus (long-snouted variety), another common species in the Ria Formosa.

Scientists carry out monthly monitoring. “All the animals have been photographed beforehand so that we can identify and better monitor them after their release in the sanctuaries. The pattern of spots and the profile of the head varies”; these are unique individual characteristics that are recognised by software.

Since the last release in November 2021, the outcome has been positive. “Fortunately, we have already noticed an overall increase in populations either in the sanctuaries or in other places of the Ria Formosa. After a 96% decrease in 2021, we are already seeing an increase that we hope will continue,” said Jorge Palma.

Over the last 10 years, thousands of seahorses have been bred at the Ramalhate Marine Centre – at least 14 consecutive generations. And there have been others, outside this count, in order to avoid inbreeding.

“Breeding an animal in captivity is regarded as a conservation tool; it is useful for research and can also be a resource for aquaculture, although the breeding of seahorses is much more difficult than that of fish produced commercially for human consumption. By the time the juveniles are born, they are already mini-adults”, and they require mainly a natural diet based on small crustaceans. “We have carried out research into their nutritional requirements, and seahorses need, for example, carotenes just like we do as vertebrates,” he explains.

When Jorge Palma began studying captive breeding in 2007, “the survival rate was zero. Today it is around 50% to 60%”. But if there is one very important aspect that researchers have realised is that seahorses are intrinsically dependent on their environment in the Ria Formosa.

“Even with a good nutritional profile, if we only give them artificial feed, which is sterile in terms of the enzymes and amino acids they need to process digestion, they won’t grow or survive” successfully. “You always need a fraction of natural feed.”

This is why they “depend a lot” on their environment, even during the process of breeding in captivity. And this is also one of the reasons why CCMAR is today the only centre in Europe to reproduce, breed and study these marine animals in depth.

Environmental quality, however, is changing “due to the pressures that the Ria Formosa is under. There was a time when illegal fishing directly impacted on the populations”, but today the problem is mainly to do with “the degradation of the waterbed”, Jorge Palma said. Another problem is the invasion of Caulerpa prolifera (seaweed), a Mediterranean species which is growing fast due to climate change. “Winter waters are warmer now”, which has facilitated the alga’s invasion of lagoon systems like the Ria Formosa. However, scientists believe the seahorses will be able to adapt and that nature will find a balance.

Soon, the sanctuary areas will be signposted. In the Culatra area (560,000 square metres), buoys will be placed to prevent navigation. In the area near Faro (100,000sqm), on the banks of the main channel, information boards will be put up, backlit at night with photovoltaic energy.

Since the time Jorge Palma started working with wild seahorses in the laboratory, much has changed in collective awareness. Thanks to the work of scientists, the public is now more aware of the need to conserve this iconic animal living in the Ria Formosa.

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