HTML Document Marine fauna

Release date 26/12/2007
Geographical coverage Morocco
Keywords Marine Fauna, endemic, Endangered species, introduced and invasive

Marine fauna, again incompletely inventoried, is counted at 7,136 known species.  Its organization is analoguous to that of world marine fauna, with the predominance of Arthropods, Mollusks, and Vertebrates that, together, constitute among 65% of the total of known fauna in Morocco, a value very close to that calculated on the world scale. The Arthropods (27% of the total fauna) are especially represented by Crustaceans; the Mollusks (22%) by the Gasteropods and Lamellibranches; andn the Vertebrates (16%) by fish. The rest of this fauna is divided over 15 branchings of variable importance.

Zooplanctonic marine fauna of Morocco seems the most diversified of all the Mediterranean, with 1063 species, represented in great part (65%) by Crustaceans, especially the Copepods (cf. Table 8). Fish, represented under the form of eggs and spawn, constitute around 3% of zooplancton species. The zooplancton represented an extremely important link in the trophic chain of numerous species of economic interest.

Endangered species

The endangered marine species in Morocco include 271 species (or 3.75% of the total marine fauna of our country), of which 108 are corrals, 85 species of fish, 23 crustaceans, 21 marine mammals, 20 mollusks, 6 marine turtles, 5 sponges, and finally 2 agnathes".

The endangered sponges belong to two genuses Spongia and Hippospongia. These sponges are not, of course, overexploited nor even exploited in Morocco, but they are so rare and probably affected by a viral epidemic that has decimated their population in the Mediterranean that they should be ‘strictly forbidden’ to fishing.

The endangered Cnidaires of our coasts count 108 corrals, or almost a third of the total of this group. They are equally menaced at the international scale.  It concerns the red Coral (Corallim rubrum), numerous black, and white corral (Scleractiniaires, Stylasterides and Antipathaires), as well as the Gorgonaire Eunicella verrucaria. The danger essentially weighs on the species and the over exploitation of their stocks and the destruction of their population by various fishing machines like the deep trawl.

On the national scale, red Coral, endangered in all its area of dispersion, is over exploited in numerous points (Asilah, Larache, Al Hoceima, etc.). For example, in the Mediterranean deposit of Al Hoceima, the collection of red Corral has fallen 4815 kg, in 1984 to only 183 kg in 1991.

For other species of corral we recognize practically nothing on their status apart from the fact that they are known to be endangered in practically all areas of distribution. These very vulnerable corrals demand tens of years to reach their commercial height, and should be considered endangered in all parts of the world.

The most endangered Mollusks of our waters number 20, which constitutes 1.12% of the total of the group. It is more particularly about the Cephalopodes and the Bivalves. They are essentially menaced by the antropique action (pollution, overexploitation and destruction of their habitats). It is principally about the Venerupis decussata and Cerastoderma edule, which are limited in estuaries and lagoons, as well as Callista chione, Perna perna and Mytilis sp. The first species is very exploited in the Mediterranean, the second in the Atlantic, and the mussels (Mytilus) along the two maritime facades.

The species Pinna nobilis and Ostrea edulis, which have disappeared from many points of the Mediterranean, exist still in small deposits in the Lagoon of Nador, but are subjugated to pollution and to poaching.  Another Gasteropode Mollusk, Patella ferruginea, equally endangered in the Mediterranean, is becoming more and rarer on our rocky coasts.

Among the most endangered Crustaceans, figuring 23 species: Aristeomorpha foliacea, Aristeus antennatus, Plesiopenaeus edwardsianus, Aristeus varidans, Crangon crongon, Palaemon serratus, Heterocarpus ensifer, Parapandalus narval, Plesionika martia, Solenocera membranacea, Parapenaeus longirostris, Penaeopsis serratus, Penaeus kerathurus, penaeus notialis, Sicyonia galeata, Scyllarides latus, Scyllarus arctus, Homarus gammarus, Nephrops norvegicus, Palinurus elephas, Palinurus mauritanicus, Palinurus regius.

The majority of species are shrimp, but, there are also ‘Homard’, ‘les Cigales de mer’, crayfish and prawn, which begin to be rarer on our coasts, especially in the northern zone of the Kingdom. One must perhaps add to this list the crab Cancer pagurus, very appreciated by European consumers. The crab exists in our country, though rare and its status is practically unknown. The most endangered group is certainly the Pisces, a group which plays a strategic role in the Moroccan economy and a crucial ecological role in the equilibrium of the marine ecosystem. A great number of species (close to 90) are exploited as much by coastal ships and high Moroccan seas as by those of other countries connected to Morocco by fishing treaties (The European Union, Russia, Japan, etc...). Among these fish, there are essentially sardines, ‘sardinelle’, anchovies, ‘chinchard’, ‘les thonides’, “les scobrides, ‘merlu’, ‘pageot’, red mullet, etc... which constitute the essential of the fishing.  Other species like ‘aloses’ (Alosa alosa, Alosa falax) and eel (Anguilla anguilla), amphihaline species, suffer other types of dangers. The ‘aloses’ have been affected by pollution (in particular in the principal sites of the Oued Sebou and Oued Bou Regreg), but also by the construction of hydrolic openings (dams) that have considerably lessened the arrival of freshwater in the estuaries, as well as by the intense pressure by fishers on the very valued species in Morocco.  As for eel, added to these anthropic actions, it is subjected to an anarchical overexploitation of its larval stage (‘civelle’) which are of very high market demand.

All the six species of marine turtles that can be encountered on the Moroccan coasts are endangered, just as on the world scale. The most common species in Morocco, the Caouanne turtle (Caretta caretta), is often accidentally pulled out in the nets of fishermen. For example, the only given statistics which exist on this species and which dates from 1991 shows that in only one year, 3581 of these species were pulled out on the Mediterranean facade of our country. The Turtle-luth (Dermochelys coriacea) is equally endangered by accidental fishing, especially on the Saharan coasts of Morocco. In the south of Morocco and in Mauritania, another species, the green turtle (Chelonia mydas), is very well liked by the local population, which could hinder the maintainance of this population if rational measures of exploitation are not instituted. Other species, like the overlapping Turtle (Eretmochelys imbricata), the Kemp turtle (Lepidochelys kempi) and the olivace Turtle (Lepidochelys olivacea), are all very rare in our region.

The majority of marine Mammals which can be found along the Moroccan coast (21 species), of which the numerous Odontocetes, all the Mysticetes and the Pinnipede (Monachus monachus), are much endangered on our coasts, just as on the world scale. Two of these Mammals, the blue Whale (Balaenoptera musculus) and the ‘franche’ Whale (Balaena glacialis), have completely disappeared from our waters, the latter having been in the Bay of Cintra (Saharan coast at the extreme south of Morocco) an appropriate place for its reproduction and more particularly the place where it gave birth. The Jubarte (Megaptera novaengliae), equally very endangered at the world scale, has become extremely rare on our coasts, even though the Moroccan Atlantic waters are considered its route of migration.

The monk Seal (Monachus monachus) has practically disappeared from all the Mediterranean facade of the country and from all the northern part of the Atlantic facade to be confined in a very restricted zone on the Saharan coast called “The coast of seals.”  Among the causes for this dramatic regression are the massacres of the Saharan population of this species by the Portugueese, accidental fishing, the overexploitation of halieutic ressources constituting its food, the destruction of its sites of reproduction. There are also some natural causes like the collapse of certain of the caves that served as shelters for this species, or, in June 1997, the poisoning and the death of sixty of them by colored waters.

The hump-backed Dolphin (Sousa teuszii), found recently on our southern coasts (1990) is essentially menaced because of weak strength at the regional and world scale but, also, because its repartition area is very restricted.

The other Cetaces of Morocco are essentially menaced by the accidental capture and by rarefaction following an overexploitation of halieutic ressources.

Endemic species

Many systematic groups have endemic representatives in our country: Spongidae, Coelenterata, polychetes Annelida, Sipuncula, Bryozoa, Brachiopodes, Mollusca, Echinoderata, Chaetognatha, Urocordata and Pisces.

The Spongidae are constituted by 12 endemic species of the ibero-Moroccan species (the total of endemism at 3.3%), discovered mostly over nine genuses (Petrosia, Bubaropsis, Gellius, Halicometes, Histodermion, Polymastia, Quasilina, Oceanapia and Raspailia).

The Coelenterata are represented by 8 endemic species (the endemic total at 1.83%), of which the majority has not been discovered until recently in the waters of the Moroccan region, and which are part of the genuses Plumularia, Halecium, Asterosmilia, Placotrochides, Stylaster and Crypthelia.

Polymastia Annelidas are counted at 9 endemic species (endemic total at 2.05%) belonging to the genuses Lysippe, Melinna, Mastobranchus, Ambo, Cirrinereis, Nereis and Panousea. The two recently discovered species in Moroccan waters respectively in 1995 and 1996 are Tharyx retieri and Diopatra marocensis.

The Arthropods are counted at 58 endemic species (endemic total at 1.88%) representing for them alone the quarter of the total of endemic species, and belonging generally either to the very little studied groups on the scale of Morocco, or to little or not at all studied regions (estuaries and Saharan region). They are species belonging to the genuses Danielopolina, Eupolycope, Hemicytherura, Leptocythere, Loxoconcha, Neocytherideis, Ruggiera, Semicytherura, Trachyleberis, Junctichela, Sarsiella, Rutiderma, Euphilomedes, Philomedes, Pseudophilimedes, Parastenope, Synasterope, Balanus, Lithoglypptes, Diastylis, Campylaspis, Makrokylindrus, Apseudes, Cyathura, Eurydice, Lakenosphaera, Pentidotea, Parachiridotea, Ganthesia, Arcturella, Astacilla, Gnathia, Unciola, Maeropsis, Euonyx, Socarnopsis, Liropus, Asthenognatus, Phyllactella, Lilljeborgia, Sympleustes and Podoceropsis.

The Sipunculas are counted at two under-species (Golfingia abyssorum punctata and G. rugosa mauritaniense) endemic to the Moroccacn region, though the Chaetognathes, the Brachiopods, the Echiuriens and the Pisces are each represented by one endemic species (respective endemic total of 3.44%; 0.2%; 11.11% and 0.08%).

The Urocordata are counted at 18 endemic species (endemic total at 15.78%) belonging to the genuses Molgula, Psilotyela, Polycarpa, Styela, Polycitor, Eudistmoa, Liouvillea, Ypsilocarpa, Synoicum, Trididemnum, Didemnum, and Aplidium. With the Echinodermatas, the endemic total is at 6%. They are species belonging to the genuses Hyphalaster, Luidia, Zoroaster, Ophiacantha, Antedon, Gephyrocrinus, Pentacrinus, Neomorphaster, Ophiernus and Ophiomitrella.

The faunistic group which shows the greatest number of endemic forms in the Moroccan region is the Mollusks who, with 84 known species, represents a little more than the third of the total of endemic species; the endemic total remains nonetheless relatively small (5.2%). The majority of these species come from the Saharan region that is not yet entirely explored, and belong to the genuses Cerithium, Actaeopyramis, Haminaea, Runcina, Aplysia, Berthellina, Aglaja, Limopsis, Crenella, Dentalium, Arca, Nesis, Abra, Cuspidaria, Pholadomya, Verticordia, Donovania, Anura, Turbonilla, Calliostoma, Monodonta, Doto, Gibbula, Solariella, Cerithiopsis, Cyclostrema, Cymbium, Turris, Cythara, Thesbia, Odostomia, Eulimella, Fissurella, Fussus, Hydrobia, Marginella, Persicula, Nassa, Ringicula, Cingula, Rissoa, Murex, Placida, Tornatina, Tritonalia, Trophon, Ercolonia, Styliger, Chromodoris, Bermudella, Favorinus, Vexillum, Euthria, Mytilimeria and Tambja.

Finally, the Bryozoaires are counted at about thirty endemic species belonging to the genuses Idmonea, Entalophoroecia, Tubilipora, Cellarina, Cellaria, Cellepora, Costozzia, Schismopora, Puellina, Spiralaria, Hippodiplosia, Schizomavella, Schizoporella, Schizellozoon, Codonella, Smittina, Porella, Microporella, Holoporella, Electra, Adeonellopsis, Schizotheca, Acanthodesia, Rigionula and Peristomella.

In conclusion, with an endemic total of 3.31%, Morocco is among the countries which have a normal endemic percentage, but this endemic amount should, in principal, be more elevated for two reasons: numerous sectors of the Moroccan coasts are still unexplored; the real prospective surface is considerably weaker than that one used for the calculation of this indication.

Harmful species (introduced and invasive)

The only species which can be considered invasive are the medusas.  These Cnidaires, under certain hydorlogical conditions, become very abundant on coastal zones, causing sometimes trouble for the summer bathers. The two species known until today in Moroccan waters are Aurelia aurita and, mostly, Pelagia noctiluca. This last one has particularly retained the attention of biologists because of its spectacular swarming, to the point that we speak of “bloom” in the manner of “phytoplanctonic bloom”. The ancient designation of “Medusa soups” describing from the eighteenth century the amplitude of the proliferation of this species, is eloquent.  The invasive swarming of this species coincides generally with a deficit of rainfall, periods of high pressure and high temperatures.

It is equally possible to consider the proliferation of mussels (Mytilus, Perna) in the pipes of heated water in thermo-electric factories as a sort of invasion since, under the effect of the temperature of used waters, they take on an exuberant development, considerably reducing the diameter of water canalizations; this results in negative repercussions on the production of electricity and the profitability of factories.

Harmful species total 81, dominated essentially by the group of Crustacean (47 species), Bacteria and Viruses (14), Mollusks (5), Plathelminths (5), Polychetes (4), Acanthocephales (2), Echinoderms (2), and Cnidairs (2).

The germs identified in the waters, in the sediment or in the marine Mollusks of Morocco are: Aeromonas hydrophila, Esherichia coli, Streptococcus bovis, S. equinus, S. faecalis, S. faecium, Vibrio alginolyticus, V. anguillarum, V. fluviatilis, V. harveyi, V. metschinokovii, V. parahaemolyticus, V. vulnificus, staphylococs, clostridums and salmonellas.  Like all germs, they can cause dermic or instestinal diseases, sometimes very serious for man, just as they can be at the origin of considerable damage in the population of Lamellibranches in certain aquacole sites.

The above mentioned Cnidaire, Pelagia noctiluca, discomforting and noxious for summer bathers, can be at the origin of considerable damage in fisheries. The cutaneous lesions left by this medusa on the surface of the body of amassed fish in floating cage can render them very vulnerable to parasites and, thus, have a negative repercussion on their production and their market value.

For the Acanthocephales, the harmful species Neochinorhynchus agilis and Acanthocephalus propinquus are at the origin of serious metabolic perturbations of fish populations, in particular the slowing down of the growth and the massive mortality of young ones, especially in fisheries. 

The Plathelminthes are also parasites of fish that can affect the metabolism of their hosts (especially growth and then their market value). The species found on Moroccan coasts are: Metamicrocotyla cephalus, Microcotyle mugilis, boothriocephalus andresi, B. gregarius and B. renaudii.

The four Polychetes Polydora ciliata, P. hoplura, P. caeca and P. armata are the parasites of oysters especially in ostreiculture parks and depreciate often the quality of their market value.

The Echinoderm Asterides are voracious predators of Lamellibranches. Among the most harmful of these species along the Moroccan coasts, one can cite Asterias rubens (oyster Star) avid of mussels and oysters. It is considered as one of the most menacing enemies of ostreiculture parks. Another asterid (Marthasterias glacialis) prefers to attack other Echinodermic Echinides, such as Paracentrotus lividus which may have an economic value.

Numerous Crustaceans are parasites of fish.  By acting on the resistance of their hosts which become thus more vulnerable to diseases, they can cause damage that is not negligible in the natural populations as well as in fisheries.  Among the species found on Moroccan coasts, one can cite numerous Isopodes Cymothoides (Meinertia aesteroides, M. steindachneri, M. collaris typica, M. collaris africana, M. collarisu globulifera, M. italica, Nerocila cephalotes, N. maculata, N. orbignyi, Lironeca sp., Anilocra physodes. A. frontalis, A. capensis, Cirolana cranchi, Cymothoa brasiliensis, Irolana nana, Cymothocya epimerica and Iduso dieuzeidei).

The Bopyres Pleurocryptella formosa and Bopyrus squillarum are equally important by the amplitude of damage that they can cause on their hosts; the female of Bopyrus squillarum, for example, provokes a high deformation on one side of the pink shrimp, which is of great commercial value.

The Gnathiidae (Gnathia falax, G. inopinata and Paragnathia formica) are also Isopodes parasites of fish: their larvas attach themselves on the fish, feed on their blood and fall, afterwards, on the bottom so as to sedentarize, metamorphosize and give adults.

As parassites of fish, there is also the Copepodes of which Alella macrotrachelus, Clavellopsis sargi, C. strumosa, C. characis, Caligus pageti, c. ligustus, C. apodus, C. pagelli, C. mugilis, Cucullanus sp., Ergasilus lizae, Lernaea branchialis, Lernanthropus brevis, Neobranchia cygniformis, Hateschekia pagellibogneravei, Elytrophora brachyptera and Nogagus elongatus. The Mytilicoles (Mytilicola intestinalis), other Copepodes, parassites this time of Lamellibranches, in particular the intestines of mussels, oysters, and coche, attacking themselves to these mollusks (in natural settings as well as conchylicole park), bringing about the reduction of their resistance, their thining and, sometimes, great mortality in these mytilicolic and ostreiculture parks. The infested mollusks are weakened and are less able to be conserved and thus to be commercialized.

The Rhizocephalas are parassite Crustaceans almost exclusively of crabs that, once invaded, have their metabolism greatly modified with a slowing down of growth and, especially, atrophy of genital glands.  The two common species of Moroccan coasts are Sacculina carcini and Sacculina gonoplacis.

The Pinnotheres (Pinnotheres pisum) are parassite crabs of mussels and oysters, sometimes very abundant in their hosts. These crabs feed on nutritiants that the mollusks have concentrated in their cavities, without causing other damage than the weak erosion of their gills.

Another Crustacean (Limmoria lignorum) bores large and long galleries in immersed wood, landing stages and the hull of ships; the damage caused can be very great.

The two Crustaceans Calappa granulata and Carcinus maenas, benthic Decapodes, though they may have a nutritive value, are considerable harmful along Moroccan coasts since, very abundant in some areas, they are at the origin of plugging and thus of the loss of fishing nets.

The harmful Mollusks are mostly those that attach themselves to wood and to rocks.  In immersed wood, landing stages, and the hull of ships, the ‘tarets’ (Teredo convexa, T. malleolus, T. norvegica, T. pedicellata, T. phaseolina) bore equally long and large galleries; the damage caused can be considerable.  The piers of stone are also attacked by many other species of mollusks, especiallly the lithopages (Lithophagia aristata and L. lithophaga).

Among the harmful Vertebrate which could have serious consequences on the development and yield of fish, there are the lampreys (Pteromyzon marinus and Lampetra fluviatilis) and the ‘myxines’ (Myxine glutinosa and Myxine ios). The lampreys attach themselves on their prey with their suction-mouth; their rapacious tongue and their rough edged ‘cornees’ tap the skin of fish and provoke open and bleeding plaits, tearing deeply the tissue and sucking in the stripped meat.  As for ‘myxines’, they attack large fish (cod, tuna, etc...) and do not let go. They incrust themselves deeply in the body of their host to live there completely; the fish is thus slowly devoured alive in a process that can last months.