The sea surrounding the Spanish peninsula and archipelagos is much more than a beautiful landscape for going to the beach: it is a true mosaic of marine species, habitats and biological communities which number in the thousands. From the cold Atlantic waters to the more temperate Mediterranean, organisms of very different origins mix together, having found here an ideal place to live, reproduce or simply make a stop in their migrations.
In this article we will explore, in an orderly fashion, a good part of that diversity: algae, invertebrates, fish, marine mammals, turtles, marine plants And, in addition, we'll cover the main legal measures and conservation programs being implemented. We'll also review those species that, while fascinating, can cause stings or injuries to swimmers, so you know what's in the water when you swim and why it's so important to protect it.
Marine biodiversity on the Spanish coast
The combination of factors such as the Strait of Gibraltar, the Atlantic influence, the Mediterranean and subtropical African waters means that in areas like Malaga or the Canary Islands Atlantic, Mediterranean, Macaronesian and subtropical speciesThis means that only in certain sections of the coastline have the following been described:
- More than 100 different species of seabirds or aquatic birds.
- More than coastal plants and 3 species of phanerogams (flowering marine plants).
- More than cetaceans different (whales, dolphins, pilot whales, beaked whales…).
- 4 species of sea turtles present on a regular basis.
- More than 200 species of fish coastal and pelagic.
- More than marine invertebrates among mollusks, crustaceans, echinoderms, cnidarians, polychaetes, bryozoans and sponges.
- More than 150 species of seaweed, both green, brown and red.
This biological richness is organized into some 60 different biotic communities, which range from sandy beaches and cliffs to underwater meadows, dune systems, marshes, river mouths and coralligenous rocky bottoms where corals, gorgonians and sponges proliferate.
Algae and marine plants: the foundation of ecosystems
Algae and marine plants are the first link in many food chains and also generate oxygen and fix CO₂2 and provide refuge for a multitude of species. Official lists of marine fauna and flora highlight the following: dozens of different algae and several marine flowering plants, as shown by cases of Toxic algae that threatens marine life.
Among the green algae (chlorophyceae) are species such as Caulerpa prolifera, Codium bursa, Flabellia petiolata, Ulva lactuca, Ulva rigida o Valonia utricularis, which cover rocks, tidal pools and shallow bottoms, serving as food for herbivores such as the salema or the vieja.
Brown algae (Phaeophyceae) include large formations, for example Cystoseira mediterranea, Cystoseira tamariscifolia, Laminaria ochroleuca or Sargassum vulgareThese "tree algae" form veritable underwater forests where juvenile fish, invertebrates, and numerous species of mollusks find refuge.
Also very striking are the red algae (Rhodophyceae), with representatives such as Asparagopsis armata, Gelidium spinosum, Jania rubens, Laurencia obtusa o Nemalion helminthoidesSeveral of them form calcareous (coralline) crusts that consolidate the rocky substrate and participate in the formation of the coralligenous habitat.
As for true marine plants (phanerogams), in Spain we find meadows of Posidonia oceanica (in the Mediterranean) and of Cymodocea knotosa y zoster noltiiThese meadows act as "nurseries" de peces and invertebrates, stabilize the sand and are key to the health of the coastline, which is why many are under special protection.
In the waters of the Valencian Community, for example, small populations of Halophila decipiens, a phanerogam with delicate leaves popularly known as "sand leaves", which colonizes soft substrates and adds complexity to the habitat.
Marine invertebrates: sponges, corals, worms and company
Invertebrates make up the bulk of cataloged marine speciesTheir variety of shapes, colors, and ecological functions is enormous, and many of them are completely unknown to the average bather even though they are right under their feet.
Cnidarians and “coelenterates”: jellyfish, anemones, corals and gorgonians
Within the cnidarians we find sea jellyfishAnemones and corals range from microscopic species to large colonial organisms. Jellyfish such as [insert jellyfish species here] are particularly prominent on our coasts. Cotylorhiza tuberculata (fried egg jellyfish or curdled water), Rhizostoma pulmo (blue jellyfish or acalefo azul), Aurelia aurita (common jellyfish) and Pelagia noctiluca, famous for its luminescence and its particularly painful sting.
The most dangerous species occasionally documented in Spanish waters is the Portuguese man-of-war (Physalia physalis)It is actually a floating colony of polyps and not a "pure" jellyfish. Its tentacles can extend for several tens of meters, and its venom can cause severe burns and even life-threatening situations in sensitive individuals, children, or the elderly.
The group of sea anemones includes many species well known to divers and fishermen: Actinia equina (sea tomato), Anemonia sulcata (sucking), Aiptasia mutabilis, several species of Telmatactis and the striking polyps of Parazoanthus axinellaeAll of them possess stinging cells, but the degree of reaction in human skin varies greatly from one to another.
Corals and gorgonians are also well represented: there are hard corals such as Dendrophyllia ramea (orange coral), Leptopsammia privoticold-water white corals such as lophelia pertusa y Madrepora oculataas well as numerous gorgonians (Eunicella verrucosa, Leptogorgia sarmentosa, Paramuricea grayi, among others). Many of these species form three-dimensional habitats that increase the complexity of the seabed and associated biodiversity.
Sponges and sea squirts
Sponges (Porifera) carpet rocky walls, caves, and shady areas with a wide variety of shapes and colors. Species such as [insert species here] appear in catalogs of the Spanish coast. Verongia aerophoba (yellow sponge), Suberites domuncula (hermit sponge), spongia officinalis (bath sponge), Axinella damicornis, Axinella polypoides, Chondrosia reniformis o Clathrina clathrusSome have had historical importance in the fishing of sponges for domestic use.
The ascidians and other tunicates (subphylum Tunicata), such as Ascidia mentula o Halocynthia papillosaThey often go unnoticed but are very efficient filters: they pump large volumes of water, helping to purify it and recycle nutrients.
Marine worms and other less visible groups
Marine worms (mainly polychaetes) include such striking species as the fireworm (Hermodice carunculata), with stinging bristles, or the spectacular tube-dwelling creatures like Sabella Spallanzanii y Serpula vermicularis, which display fan-shaped filtering plumes.
Other inconspicuous but abundant invertebrates are the bryozoans, some with a coral-like appearance (for example Myriapora truncata, known as false coral, or Reteporella grimaldii, the “Venus lace”), which form fine calcareous structures on rocks. There are also little-known groups such as the ctenophores (for example Beroe ovata) and gelatinous organisms such as salps (Salpa fusiformis, Salpa maxima), which form floating chains that filter plankton.
Echinoderms, crustaceans and mollusks: the "classic" fauna of the seabed
When we think of marine fauna found on rocky and sandy shores, sea urchins, starfish, crabs, shrimp, octopuses, and seashells come to mind. All of these are extraordinarily well represented along the Spanish coast, with official lists that include dozens of species of echinoderms, almost a hundred crustaceans and more than 150 mollusks.
Echinoderms: sea urchins, starfish, and sea cucumbers
Among the echinoderms, sea urchins stand out, such as paracentrotus lividus (common sea urchin), Arbacia lixula (black hedgehog), Sphaerechinus granularis (puffer hedgehog) or heart hedgehogs like Spatangus purpureusIts thorns can cause very painful injectionswith stinging and inflammation; some species even secrete toxic substances from glands located in the spines.
In the group of starfish we found the robust Marthasterias glacialis (pointed star), Echinaster sepositus (red star), Ophidiaster ophidianus (purple star), as well as brittle stars (fragile stars) like Ophiothrix fragilis u Ophiocomina nigra, which are usually hidden under stones and in crevices.
The holothurians, popularly known as sea cucumbers or “pingaburros”, include species such as Holothuria sanctori o Holothuria tubulosaThey are great recyclers of sediments: they ingest sand and organic matter and return the sediment "clean", contributing to the oxygenation of the bottom.
Crustaceans: crabs, lobsters, and shrimp
The group of marine and freshwater crustaceans includes crabs, lobsters, prawns, shrimp, barnacles, and barnacles. They have been cataloged dozens of different species, with an enormous diversity of life forms, from hermit crabs to cleaner shrimp.
Among the coastal and rock crabs are Pachygrapsus marmoratus (juyón), Eriphia verrucosa (Moorish crab or jack), Carcinus maenas (green crab) or Necora puber (crab). In deeper waters, species of fishing interest appear such as cancer pagurus (edible crab) or the royal crabs of the genus Calappa.
Lobsters and related creatures are represented by the European lobster (Homarus gammarus), red lobster (Palinurus elephas) and the "muscled" lobsters like Scyllarus arctus (santiaguiño) or Scyllarides latusDecapod crustaceans also include commercially valuable shrimp and prawns such as Nephrops norvegicus (crayfish), Aristaeopsis edwardsiana (police officer) or Parapenaeus longirostris (white shrimp).
Symbiotic crustaceans are not lacking, such as small shrimp that live in association with anemones, sea urchins, sponges or gorgonians, nor the barnacles (Pollicipes pollicipes) and other barnacles such as Balanus trigonus o Megabalanus tintinnabulum, which cover rocks in the surf zone.
Mollusks: from limpets and snails to squid and octopus
The group of mollusks and related organisms is one of the most prolific along the entire coastline: more than 160 cataloged species which include bivalves (clams, mussels), gastropods (snails, limpets, nudibranchs) and cephalopods (octopuses, squid, cuttlefish).
Among the bivalves, commonly consumed species include leg leg (clam), Warty Venus (warty clam), Noah's Ark (Noah's Ark), Pinna rudis (sea comb) or Spondylus senegalensis (oyster). Some, like the date palm (Lithophaga lithophaga)They are strictly protected due to the significant impact their extraction has on the rock where they live.
Limpets are abundant in rocks and tidal pools (Patella ulyssiponensis, Patella candei, Patella piperata), as well as small snails such as the “burgados” (Osilinus atrata, Gibbula magus, Gibbula cineraria) or the “little shells” of the genre Trivia and the porcelain (Luria lurida, Zonaria pyrum).
Cephalopods constitute another star group: the common octopus (Octopus vulgaris), cuttlefish (Sepia officinalis), the common squid (Loligo vulgaris), various open-water squid and cuttlefish (Ommastrephes bartramii, Todarodes sagittatus, Illex coindetii), as well as curious species such as the Spirulina (Spirula spirula) or vampire octopus (Tremoctopus violaceus).
Nudibranchs and sea slugs are a special case: they are small, colorful, and highly prized by underwater photographers. Species such as Hypselodoris picta, Limacia clavigera, Peltodoris atromaculata (the Swiss cow) or various Aplysia, known as sea rabbits.
Marine fish: from the shallow shore to the great depths
The list de peces The marine life that can be observed in Spanish waters is impressive: they have been cataloged More than 350 species, from small gobies and blennies to large ocean predators such as tuna, swordfish and various sharks.
The shallow bottoms of rock and sand are home to the species most familiar to bathers: red mullet (Mullus surmuletus), gilthead seabream (Sparus auratus), sargos (Diplodus spp.), salemas (Sarpa salpa), old women (Sparisoma cretense), mackerel (Scomber colias), bogas (Boops boops) or the colorful ones Green fish (Thalassoma pavo) y maidens (Coris julis).
In mixed areas of rock and sand, there are many wrasses (rosemary, cowherds), the mountain ranges such as the little cow (Serranus scriba) or the goats (Serranus atricauda, Serranus cabrilla) and, in places with crevices and shelters, groupers and abbots (Epinephelus marginatus, Mycteroperca fusca), which are authentic emblems of Mediterranean and Canary Island fauna.
In deeper, more open waters move large migratory birds such as the bluefin tuna (Thunnus thynnus), the yellowtail amberjack (Thunnus albacares), prickly pear (Thunnus obesus), the bigeye wolf (Thunnus alalunga), tuna (Auxis rochei), bonitos (Katsuwonus pelamis) and other tunas and scombrids such as sarda sarda o Orcynopsis unicolor.
There is no shortage of curious species such as the moonfish (Mola mola) and his relatives, the clockfish (Zeus faber), pejesables (Lepidopus caudatus, Aphanopus carbo), various stripes (genres Raja, Dipturus, Leucoraja), guitarfish (Rhinobatos) and a multitude of sharks, from the basking shark (Cetorhinus maximus) even deep-sea species like Etmopterus spinax, Centrophorus granulosus, Oxynotus centrina or the enigmatic pejesremios (Regalcus glesne).
In the intertidal zone and down to a few meters deep, small fish such as the blennies (bellied blennies), gobies (cabozos), needlefish and seahorses (Hippocampus hippocampus, Hippocampus guttulatus), especially vulnerable to the degradation of their habitats.
Sea turtles, mammals, and other large marine vertebrates
Also de peces and invertebrates, our waters harbor large marine vertebrates that arouse much social and scientific interest: turtles, cetaceans and, although already extraordinarily scarce, the monk seal.
Sea turtles
In the Mediterranean and the Atlantic near the peninsula, four species of sea turtles are observed with some frequency: the loggerhead sea turtle (Caretta caretta), leatherback turtle (Dermochelys coriacea), hawksbill turtle (Eretmochelys imbricata) and green turtle (Chelonia mydas)Many of them are regular visitors that use these waters as feeding grounds or migratory stopover points.
All sea turtles are included in lists of protected and endangered species internationally, and Spain has an obligation to protect them through the sea turtle protection, the reduction of accidental catches, the proper management of spawning beaches and the care of stranded or injured specimens.
Cetaceans and monk seal
The list of marine mammals that can be sighted in Spanish waters is very extensive: sperm whales (Physeter macrocephalus), various rorquals (blue, common, minke, bowhead, tropical), right whales (Eubalaena glacialis), humpback whales (Megaptera novaeangliae), orcas (Orcinus orca), pilot whales (Globicephala melas, G. macrorhynchus), dolphins (common, striped, bottlenose, spotted, rough-toothed, Fraser's), false killer whales (Pseudorca crassidens) and several beaked whales (Ziphius cavirostris, Mesoplodon spp., Hyperoodon ampullatus).
Historically, it was also present monk seal (Monachus monachus)It is now practically extinct from our coasts but still has populations in other areas of the eastern Mediterranean and eastern Atlantic. It is one of the most endangered seals on the planet.
Dangerous species for swimmers: jellyfish, poisonous fish and other common hazards
The large number of species means that, from time to time, some may cause us harm. bites, punctures, or injuries If we step on them, touch them, or inadvertently cross paths with them. This isn't about causing alarm, but about knowing what's there and how to react.
Among the latests Moravia's compositions Jellyfish We have already mentioned several relevant ones: Cotylorhiza tuberculata (very slight or almost imperceptible sting), Rhizostoma pulmo (intense itching), Aurelia aurita (slight discomfort) and Pelagia noctilucawhich can cause intense burning, pain, and slow-healing injuries. The occasional presence of the Portuguese caravel It requires taking extra precautions when the authorities issue warnings.
Among the fish that are dangerous for bare feet are the weever fish (Trachinus draco, Echiichthys vipera)which buries itself in the sand in shallow areas and has poisonous spines on its back and head, and the toadfish or miracielo (Uranoscopus scaber), which also has a poisonous spine and lives half-buried in soft bottoms.
La scorpionfish or scorpionfish (Scorpaena scrofa and related species) It is another species to be aware of: its dorsal spiny rays have venom glands, and the sting can cause very intense pain, local edema and even general symptoms such as dizziness or alterations in blood pressure.
Los sea urchins, especially Paracentrotus lividusSea urchins are a common cause of emergency room visits in summer: the spines can pierce the skin deeply, break, and continue to release irritants if not properly removed. The best prevention is simple: wear appropriate footwear in rocky areas and avoid leaning against walls covered in sea urchins or anemones.
We also need to consider the Stingrays (Dasyatis pastinaca and other stingrays)which have a venomous stinger on their tail. Although they do not usually attack, they can defend themselves if stepped on or disturbed, producing very painful wounds that require medical attention.
Legal framework and marine species conservation programs
The extraordinary diversity described is not free from threats: overfishing, Marine contaminationhabitat destruction, climate change The presence of invasive species is behind the decline of many populations. To curb this trend, Spain has developed a fairly robust legal and operational framework.
La Law 42/2007, on Natural Heritage and BiodiversityIt establishes the basis for protecting biodiversity, including marine species of community interest. Royal Decree 139 / 2011 It develops the List of Wild Species under Special Protection, which has subsequently been updated (for example, by Order AAA/1771/2015) to incorporate new species or change their threat category.
Furthermore, the Order AAA/75/2012 It defines the periodic assessment of the conservation status of the taxa included in that list and regulates the prohibition of actions that could negatively affect their situation. This covers everything from cetaceans and sea turtles to sharks, seabirds, and other vulnerable species.
At the regional level, regulations such as LAW 5/2017, on Maritime Fishing and Aquaculture of the Valencian CommunityThey set clear objectives: to protect fishing grounds, conserve marine biological resources and ensure sustainable exploitation from an environmental, economic and social point of view.
At the same time, the following have been launched specific programs of study, recovery and reintroduction of marine fauna, in collaboration between administrations, scientific foundations and fishermen's associations. A prime example is the agreement between the Ministry of Agriculture, Rural Development, Climate Emergency and Ecological Transition of the Valencian Community and the Oceanogràfic Foundation.
Collaboration with fishermen and stranding networks
Fishing professionals are on the front line of contact with marine wildlife, so their collaboration is key to the detection of accidental captures, strandings and sightings of protected speciesIn the Valencian Community, for example, a specific protocol has been established with the fishermen's guilds for:
- Report sightings of cetaceans and record interactions with fishing gear.
- Report accidental captures of sea turtles, elasmobranchs (sharks and rays) or other sensitive species.
- Collaborate in the collection and delivery of live specimens to the recovery teams.
Reports of strandings or accidental captures of turtles, dolphins, whales and other protected animals are usually channeled through the emergency telephone number 112, which activates the stranding network protocol and mobilizes specialized teams.
Some specific programs that are being developed include a sea turtle recovery programMarine mammals and elasmobranchs from accidental capture, which includes their collection, diagnosis, treatment, rehabilitation and subsequent release into the natural environment.
Another interesting project is the one intended to to recover populations of seahorses (Hippocampus hippocampus and H. guttulatus) and corals on the Valencian coast. The accidental capture of these animals in nets is relatively frequent, and thanks to collaboration with the fishermen's associations they can be collected, kept in specialized centers and, after studying the suitable habitats, reintroduced into the environment.
A pilot protocol is also being implemented for the Breeding and reproduction in captivity of sea urchins (Paracentrotus lividus and Arbacia lixula), with the aim of reinforcing natural populations and evaluating their evolution through scientific monitoring by institutions such as the Institute of Coastal Ecology.
Finally, applied studies such as the project are developed “Studies of the reproductive characteristics of the common octopus (Octopus vulgaris) in the waters of the Valencian Community”, coordinated by IMEDMAR-UCV together with the fishermen's guilds and the fisheries administration, to adjust fishing bans, minimum sizes and management to the actual biology of the species.
This entire network of species, habitats, regulations, and conservation programs shows the extent to which the sea we see from the shore is a complex and fragile universe, in which many coexist. jellyfish, sea urchins, turtles, whales, algae, corals and fish of all kindsKnowing them, knowing which ones can cause us problems and which ones are on the verge of collapse, and understanding how efforts are being made to protect them, is the first step to enjoying the sea with respect and ensuring that it remains a haven for life for many more generations.
