Barcelona Zoo’s work at Parc dels Esculls is helping to repair the coastal marine ecosystem

In 2003, 365 artificial concrete structures were installed along the Barcelona coast to help recover the city’s marine biodiversity and the quality of its seabed

Through its Foundation, Barcelona Zoo has monitored this project over the years and has strived to raise awareness of and preserve the marine ecosystem of the Barcelona coast

The next step will be the creation of the Marine Biodiversity Conservation Centre, which will work to preserve marine organisms and raise awareness of the need to protect endangered Mediterranean habitats

In 2003, a series of artificial concrete reefs were created along the Barcelona coast to promote the recovery of the city’s marine biodiversity and improve the quality of its seabed. This project arose as part of an initiative to repair the coast at the mouth of the Besòs river, which had undergone environmental damage due to sanitation infrastructures leaking the products of inadequately treated urban and industrial wastewater into the sea. Following improvements to the sanitation system (remodelling of the Besòs wastewater treatment plant with biological treatment and an end to sludge being pumped into the sea, environmental recovery of the mouth of the Besòs river, construction of rainwater collection tanks, etc.), there was a great opportunity to improve the environmental quality of both sea water and the seabed through marine environmental services and usages.

Sixteen years after the artificial reefs were installed, the local flora and fauna have been protected, the diversity of the marine organisms that inhabit them has increased, small-scale fishing in the area has improved and research into the local seabed has been supported, as the structure has been used as a platform for scientific trials.

During this time, Barcelona Zoo has monitored the project in a bid to protect marine biodiversity. In the process, it has observed how the artificial reefs have been colonised by various local species, such as sponges, soft corals, anemones, flat oysters, the common octopus, the European spiny lobster and a host of fish species, including the scorpionfish and the comber. The artificial reefs have also demonstrated the effects of marine current and wind storm dynamics on the coast.

Barcelona Zoo: helping to improve marine biodiversity

As detailed in its recently approved New Model, Barcelona Zoo works to preserve nature around the world, with special concern for the Mediterranean bioregion, and to combat the constant deterioration of most natural habitats. This task is carried out alongside other zoos, public authorities, institutions, universities and scientific centres, and involves promoting and collaborating on various conservation and research projects, both in the field and on the Ciutadella site.

The creation of the Parc dels Esculls artificial reefs and the studies and monitoring carried out there have improved the health of this coastal submarine habitat and led to a proliferation of diverse marine organisms. For this reason, one of the next challenges set out in the Zoo’s New Model is the creation of the Marine Biodiversity Conservation Centre, which will continue with this task, contributing to the preservation and conservation of endangered species and local and Mediterranean wildlife. The centre will also promote research and projects that aim to protect nature, as well as carrying out awareness-raising and educational activities.

For years now, the Barcelona Zoo Foundation has coordinated scientific and technical monitoring at Parc dels Esculls aimed at obtaining characteristic data on the state of the structures, their colonisation by living creatures, their possible impact on the nearby coast and the evolution of the fishing and marine communities.
Moreover, it has contributed towards raising awareness of the need to preserve marine diversity through exhibitions, educational activities, multimedia projections and scientific articles with Parc dels Esculls as the protagonist.

The purpose of the monitoring carried out by the Zoo team has been to analyse the overall situation in the area occupied by the artificial reefs and to track the diversity of the organisms found there, through observation of the marine species living around or on them and of the spatial structure of the populations linked to the modules.

It is worth noting that Parc dels Esculls is located in a natural environment that is permanently exposed to the dynamics of sea currents and to wind storms, some of which can be of a significant magnitude. One of the most serious wind storms of recent years took place in December 2008 but the area recovered quickly from its temporary loss of organisms.

The location and characteristics of Parc dels Esculls

Parc dels Esculls is located between the new entrance to Barcelona Port and the submerged groynes near the Bac de Roda wastewater pipe, covering around 11 square kilometres of seabed, over which a total of 365 submerged structures are installed.

The reefs are artificial structures made to resemble the natural rocky seabed from modules of different kinds with a rough texture to make it easier for different marine species to colonise them. As well as promoting biological diversity, the artificial reefs are designed to protect the organisms that live there from illegal fishing.

Biodiversity at Parc dels Esculls

The organisms attached to the artificial structures at Parc dels Esculls spread over any colonisable surface in contact with the water. The degree of reclamation of all the structures by plants and animals is above 100%, as several layers of organisms are located on the rough, concrete, artificial substrate.

The organisms that inhabit the structures are spread out according to the amount of light available and the type of diet they require. Algae are found at the top of the reefs, where the most sunlight reaches. On the vertical walls are filter feeders, which feed off substances suspended in the water: soft corals, Mediterranean fanworms, mussels, etc. Near the filter feeders, we find other organisms that feed off them, such as the common octopus: a soft-bodied mollusc that lives in caves and holes. Nudibranchs, a common species at Parc dels Esculls, are also soft-bodied molluscs, like a kind of marine slug, that are found in a wide range of shapes, sizes and colours. Compared to other points on the Catalan coast, Parc dels Esculls is home to a lot of this species.

Parc dels Esculls is also inhabited by the flat oyster, the European spiny lobster and the comber fish, and their population is expected to rise in the coming years. One of the fish species that has colonised this habitat most successfully is the scorpionfish, which lives in close contact with the rocky seabed and camouflages well with its surroundings.

As for the types of structures installed in 2003, the stacked cubic ones present the greatest number of inhabitants due to their horizontal and vertical dimensions, their large surface available for colonisation and their number of orifices that can be used as shelters.

The presence of marine wildlife at Parc dels Esculls

The latest studies carried out by the Zoo demonstrate that the wildlife that currently lives at Parc dels Esculls is as follows:

•    the so-called sea snail (Parablennius rouxi, Parablennius pilicornis and Parablennius gattorugine), found on all the structures, is most widely observed on the highest part of the artificial reefs
•    the scorpionfish (Scorpaena sp.) is found frequently and consistently across all the surfaces of the modules and is more abundant at night in all locations
•    the European conger (Conger conger) is increasingly present; the modules constitute an ideal habitat for it, and it often sits in the gaps on the lower levels
•    the comber (Serranus cabrilla), found on structures inhabited by highly territorial species, is mainly observed in the gaps at the intermediate and lower levels
•    various species of sea bream such as the common two-banded sea bream (Diplodus vulgaris) and the white sea bream (Diplodus sargus) are found around and inside the modules, where they find shelter and protection from their predators. Meanwhile, the saddled sea bream (Oblada melanura) moves in a school around the modules
•    the Mediterranean rainbow wrasse (Coris julis) is found at lower and intermediate levels
•    the damselfish (Chromis chromis) is abundant and, like the saddled sea bream, moves as part of a school of fish around the structures at the intermediate and upper levels during the day, but rests in the gaps in the modules at night
•    the common dentex (Dentex dentex), a species that was uncommon in this area of the coast until now, can be found between structures at the lower level
•    the grouper (Epinephelus sp.) is present in the gaps at the lower level
•    the forkbeard (Phycis phycis) is found between the stacked modules at the lower level and inside the tubes of the tubular modules
•    the cardinalfish (Apogon imberbis) is common in the gaps at the lower level
•    the bastard grunt (Pomadasys incisus) is abundant only in the spring and, like the saddled sea bream and the damselfish, moves as part of a school around the structures at the intermediate level


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