The hippocampus, mythical and mysterious marine animal officially declares itself in crisis. In reality, the crisis has spread to the whole of its submerged world and each living species that constitutes it is now fighting for its survival.
Every fight has its icon and thanks to its popularity, the seahorse is naturally the best ambassador of the seabed of our coast. Portrait of a muse:
The hippocampus, a hybrid that is not one!
Make no mistake about it, despite its chivalrous demeanor, the seahorse is very clearly identified as a fish, it breathes through gills and moves with its pectoral and dorsal fins.
It is part of the large family of syngnathids and is found under the genus Hippocampus, which represents at least thirty species in the world.
In Europe, however, we only identify two, l'long-nosed seahorse (hippocampus Guttulatus) or the short-nosed seahorse (hippocampus Hippocampus).
Their difference is mainly due to the length of their mouths and their heads, the long-nosed seahorse sports a small crown while the short-nosed seahorse has a triangular crest at the top of its skull. It would also appear that the former is slightly larger and more widespread.
Anatomy of an original fish.
Darwin and his theory of evolution would be very bothered to explain the amazing physical characteristics of the hippocampus. Biopsy of a unique fish:
A head that resembles that of a small horse with a long toothless mouth but capable of dazzling aspirations. The system of the inverted blowpipe which therefore allows the hippocampus to quietly suck up its prey when they are within range.
Its independent eyes give it binocular vision, ideal for spotting prey while monitoring the predator area. It is also a major asset for accurately measuring the distance of a prey and thus triggering an effective attack.
A body devoid of scales but reinforced by a skeleton lined with subcutaneous bony plates which guarantee it good protection against small predators.
Some more wacky seahorses even sport pretty growths and skin filaments. The body of the hippocampus is capable of'homochromy and d'homotypy, perfect for remaining invisible.
In the male, an incubator bag guarantees the reproduction and protection of offspring.
Finally, the hippocampus, deprived of ventral and caudal fins, is endowed with a prehensile tail, a feature as unique as it is useful underwater. An ability directly from the monkey? Who knows…
Hippocampus, instructions for use.
Where does he live ?
In France, the two species of seahorses are found mainly in infralittoral areas with high organic productivity such as lagoons (Bassin d'Arcachon and Thau basin…) or other parallel environments (Ria d'Etel, Rade de Brest, Gulf of Morbihan…) but it is theoretically possible to see them all along the coast.
His favorite biotope? Sandy and sandy-muddy bottoms colonized by eelgrass or Posidonia-type meadows, but it is also found in rocky areas rich in algae, sponges or ascidians.
In reality, seahorses are able to adapt to the different ecosystems of our coasts. It is common to find the same species with strong morphological variability depending on its habitat area.
Its particular morphology and the miniaturization of its fins make the hippocampus not very fast and not very enduring. It is therefore not very mobile and its only chance to make long sea voyages remains the drift, clinging to floating debris.
In fact, the seahorse swims little and the use of its two dorsal fins rather helps it to crawl or to maneuver elegantly in restricted areas.
To move is to take the risk of being spotted, so it is his camouflage abilities that offer him the best chance of survival. Capable of homochromy (ability to take the color of its environment) and homotypy (ability to take the forms of its environment), the hippocampus has serious assets and its steadfast immobility allows it to avoid its predators while by feeding without the slightest effort.
Serve the meal or serve the meal?
To survive, the rule is simple and identical for each species: feed without being eaten.
And it must be admitted that the technique of hunting the hippocampus is particularly well established, to remain motionless, invisible and wait for a prey to enter its perimeter of aspiration.
As soon as it is within range, the hippocampus slowly raises its head and begins its suction process which lasts only a fraction of a second. The suction is so clean that no eddies will disturb its prey. The latter has no chance of escaping it and sometimes even, will not realize its fate until once in the mouth of the hippocampus.
His favorite prey? Copepods and other small molluscs or crustaceans in the larval stage which are particularly abundant in their habitat area.
The hippocampus is toothless and has a rather simple digestive system, it is quite gluttonous and misses few opportunities to swallow prey.
A hunting device that is not unlike that of the Frog fish (frog fish). The latter is also a formidable predator for the seahorse in tropical waters but in our latitudes, modestly more temperate, the main natural predators of seahorses are other fish such as rays, wrasses and small sharks but sometimes also cephalopods, or even sea birds whose predation is well established in the Arcachon basin.
But unfortunately the biggest and most dangerous predator of the hippocampus is us, but we'll get to that later.
A perfect husband.
Like all animal species, the life of the hippocampus ultimately boils down to protecting itself, eating and reproducing.
And on this last point, the hippocampus is not left out in terms of originality. Monogamous, faithful and devoted, the seahorse is a perfect husband.
Concerned about the health of Madame, it is the gentleman who, after having exhilarated his beautiful with a love parade, will receive his eggs in his incubator pocket. He will then take care of their fertilization and the gestation of the eggs for a period of 3 to 4 weeks, until the birth of their offspring.
The breeding season usually starts with the first warming of the water and it can be trying for our male seahorse. An entire breeding cycle lasts between 3 and 4 weeks and can be repeated up to 5 times per season. With an average of 300 births per cycle, our couple could be parents of 1500 little seahorses per season. And yes, when we love, we do not count… However, let's relativize because only 10 to 15% of newborns reach adult size.
In Europe, our seahorses have an average lifespan of 4 to 5 years and can reach a size of 12 to 15cm or even up to twenty centimeters for the largest specimens encountered.
With its hunting, camouflage and reproduction powers, the seahorse seems armed to last but the reality is quite different.
The seahorse, a battleship in turmoil.
Beyond its air of infallible battleship, the seahorse is vulnerable and even if this is mainly due to the direct exposure of its habitat to human activities, it is also the target of vast global trafficking.
Victim of mythology.
The Greeks saw the seahorse as a creation of Poseidon and therefore associated it with strength and power. Asians, they saw the seahorses rather as a dragon spirit and gave them attributes of power and luck, a symbol also shared by sailors and it is still relevant to be offered a dried seahorse as a lucky charm.
Obviously, this symbolism relates only to ancestral beliefs where the imagination served as science.
In the world, between 35 and 40 million seahorses are estimated to be caught each year, half serving only traditional Asian medicine which lends it fortifying and aphrodisiac properties, the other half being exploited by the food industry, aquarists, or the trade in macabre souvenirs.
Ironically, the Chinese, who seem to have taken over the majority of the world's catches, prohibit seahorse fishing on their territory, preferring to source more discreetly, as evidenced by the last seizure of 12 million seahorses on a ship. Peruvian in September 2019.
This targeted and often artisanal fishing remains a disaster for monogamous seahorses who, orphaned by their half, will no longer reproduce.
Like sharks, therefore, seahorses are victims of ancestral beliefs and are the subject of vast global trafficking.
Are Europeans more serious?
In Europe, things are a little different, several conventions have given a status to the hippocampus:
- the Bern Convention on the conservation of wildlife places the two species of European seahorses in the category of " strictly protected species '.
- The Barcelona convention relating to the protection of protected areas and Mediterranean biodiversity places seahorses in the appendix of "eendangered or threatened species ».
- The OSPAR convention, for its part, places the seahorse in the category of endangered species and in decline in areas ranging from the North Sea to the Atlantic.
We can also mention the Washington Convention (CITES) which governs its trade between the 183 signatory countries. Spurred on by Amanda Vincent and Project Seahorse, the convention placed the seahorse on its Appendix II in 2002. It was then the first marine species to be protected under its agreements.
The species therefore clearly has a recognized status of threatened and protected species, but this legal framework is only a basis, and the conditions for the sustainability of the species and especially its habitat will require much more.
Stifling human demographics.
Due to their proximity to the coastal zone, seahorses and their biotope are directly subjected to the pressure of human activities, in particular:
- Non-selective fishing: trawling is indiscriminate fishing that can destroy populations and entire habitat areas in a single pass. Fishing of this type is clearly the number one enemy and to this day this practice is ecological nonsense!
- Port constructions and other dredging operations often have a heavy impact on seahorse habitat, very often causing substantial changes in the environment such as shifts in coastal marine currents or excessive and lasting sedimentation.
- Water pollution is an undeniable factor and increasingly threatens the sustainability of coastal marine biodiversity areas. Industrial discharges of pollutant-laden water, maritime transport and its hydrocarbons, agriculture and its fertilizers rich in nitrates, but also the plastic or organic waste that we throw into nature every day and which ends up sooner or later in the sea .
- And finally, let us no longer neglect the demographic pressure that the coastal areas where human activity is increasing considerably. Tourism and nautical and underwater activities or shore fishing encroach directly on the seahorse's living area.
The pressure of these activities becomes all the more worrying as it follows an ascending demographic curve and as the latest studies on eelgrass, the favorite habitat of the hippocampus, shows a clear decrease in colonized spaces.
Eelgrass, a mangrove in temperate zones.
Along our French coasts, there is an ecosystem that is considered today as a “hot-spot” of biodiversity, it is eelgrass beds. Like the Posidonia which exclusively inhabits the Mediterranean, the eelgrass meadows play a major ecological role.
Eelgrass, a flowering plant.
There are mainly two species, eelgrass and dwarf eelgrass, the first being of course larger than the second and their distribution area is slightly different, if we find eelgrass in the infralittoral zone, dwarf eelgrass, it, is found rather in the intertidal zone.
Eelgrass is not an algae but a phanerogamous plant which develops on sandy or sandy-muddy bottoms and like its terrestrial cousins, it has a foliar system composed of leaves, a stem (rhizome) and a system root.
The herbaria have a dual role, like the mangroves. They protect coasts from erosion and provide quality habitat for many species.
A giant filter that protects against erosion
By reducing the hydrodynamic energy, they are able to trap sediments and macroalgae, fix them and then filter them, greatly helping to reduce the turbidity of the water column. If you can see your feet when you bathe, eelgrass beds are no stranger to it.
This ability to fix the sediments allows them to strengthen their anchoring by stabilizing their soil and the cover of their foliage is able to attenuate the force of the waves, especially at low tides, thus limiting the movement of sediments and therefore the erosion of our ribs.
Eelgrass beds are the basis of an extremely rich ecosystem that is essential for a large number of species. In Brittany for example, it is possible to list more than 150 species of invertebrate macrofauna in a herbarium.
The role of eelgrass goes much further and its ability to provide protection to predators correlated with the abundance of nutrients available makes it an excellent breeding and nursery area. Many non-resident species choose seagrass beds to deposit their eggs and their offspring, so it is very common to find spawning squid, cuttlefish, rays or small sharks such as fruit bats.
It is obviously a very favorable environment for pipefish and seahorses, the majority of observations in Brittany coming from elsewhere in a herbarium or a nearby area.
If eelgrass is not consumed by its marine hosts, it represents a delicacy of choice for some migratory birds such as geese geese or whistling ducks which, during their passage, can destroy an area fairly quickly but their overall impact remains. quite limited.
Eelgrass, an endangered ecosystem.
Eelgrass is able to adapt to different environments but it remains very sensitive to anthropization of its environment and to rapid and prolonged changes in its parameters. Among other things, we can cite four major causes: a change in sedimentation, an increase in turbidity, an over-supply of nutrients and grubbing.
Sedimentation, luminosity and nutritional contributions:
Sensitive to sedimentation conditions, eelgrass can loosen in the event of low sediment input, but it is more often an increase in sediment that causes its loss by burial. This increase in sedimentation can occur when heavy dredging operations or port works take place but also after increasingly regular meteorological phenomena, such as storms or torrential rains.
This can also cause a marked increase in nutrient salts in the water causing the proliferation of epiphytic algae, and this sometimes results in mats of algae literally suffocating the seagrass like the green tides in Brittany for example.
This phenomenon is not uncommon in spring but it lasts longer and longer, reducing the amount of light essential for the operation of the herbarium, thus limiting the fixation of sediments and nutrients, which will end up increasing the turbidity of the plant. water and a vicious circle is then set up, the herbarium cannot regenerate and dies.
The eutrophication of coastal aquatic environments is becoming worrying and if the main reason remains high levels of nitrogen and phosphorus in Brittany, it is rather abnormal levels of hydrocarbons and biocide in the Arcachon basin.
So many different terrigenous nutrients that pollute and modify the infralittoral marine ecosystem and whose main culprits remain agriculture, industry and transport.
Fishermen and boaters not always well informed.
The coastal zone subject to the tides regularly sees hordes of foot fishermen scraping, digging and trampling the foreshore. This practice, however strictly supervised, is responsible for the crushing and destruction of many herbaria.
French and European regulations protect seagrass, whether Zoster or Posidonia, and the ban on fishing in these areas is clear. If this ban remains however respected by most fishermen, some remain capable of destroying dozens of square meters of eelgrass at each tide, with disastrous consequences on the biodiversity which the people.
The same goes for boaters who logically love sheltered coastal areas, and who regularly drop their anchor there, tearing many shots in the process.
This direct destruction by man should not be marginalized as these activities tend to increase considerably. The regulations exist, it is now a matter of making them known and applying them because bad behavior is very often the result of simple "ignorance".
Act to protect.
It is therefore urgent to make our practices sustainable because if the seahorse is in danger, it is clearly not the only one and a whole marine ecosystem could disappear. Fatality is not an option and the first thing not to do is'is to do nothing!
Each of us has an opportunity to act to conserve and perpetuate what nature offers us most incredible. Seahorses need allies, and although we are their number one enemy, we can also be their primary ally.
Learn, share and act.
There is an essential basis for all protection, and that is research. Without science and its contribution of knowledge, it is impossible to understand the interactions and their consequences on our environment. Without it, no discoveries, no wonder and no future ... Fortunately, today we have enough knowledge to share to act accordingly.
We can all act, whether through individual or collective initiatives, each civic initiative is a positive signal and will make it possible to change the practices of each one but also of industry, agriculture, transport and fishing. etc ...
Examples of individual actions:
- Respect underwater habitat areas such as eelgrass beds and Posidonia. Do not go fishing on foot in these areas, do not anchor anchors there and during our dives, focus on exploring the peripheral area, have good buoyancy and of course, nothing is taken.
- Limit your consumption of plastic and other unnecessary packaging. During our immersions, it is very common to find waste, let's collect it as much as possible. If each diver collects a piece of waste on each trip, it's a hell of a cleanup at the end of the year.
- Favor products from sustainable and especially local agriculture. Eat seasonal produce.
- Boycott fish from trawl fishing and processed fishery products such as surimi or certain seafood terrine that exclusively use fish from this type of fishing. Give priority to local and artisanal fisheries, ideally longline or line.
- Don't buy souvenirs made from animals. A dried seahorse has never brought luck, favor the 4-leaf clover.
- Denounce illegal and fraudulent practices. Social networks can mobilize public opinion quickly, a fishmonger's stall with protected species, a factory that rejects its polluted waters, so many inappropriate behaviors to denounce.
- Participate in participatory science actions and help research through our photos and other observations.
Let us act together.
Collective actions are the logical continuation of our individual actions, they are only the pooling of our actions but have some additional means and more media coverage.
With associations for the protection of nature or citizen and local initiatives, the fights waged become more visible and have a certain weight in the development of public policies and the change of global practices.
All actions in this direction deserve to be supported, either through your participation or through donations that will finance the campaigns.
Public awareness remains in my opinion the basis for the protection of seahorses and other animal species. Children are receptive and curious in this sense, they are sometimes even the first ambassadors to their families. It is therefore important to organize awareness campaigns in schools. The idea being to create an emotional or curiosity bond with the new generations, which will naturally act accordingly, it will pay off in future years.
Sustained and visible collective actions often have an influence in the development of national and European policies for the protection of species. The creation of marine protected areas (MPAs), essential for the management and control of these areas with high biodiversity, are for example only possible with the work of scientists and the support of associations.
We all have a role to play in protecting our nature and I have no doubt that everyone will understand it ...
List of associations and participatory science programs related to the hippocampus:
Blue skin: The skin-blue association is certainly the most representative for the protection of seahorses and their environment in France. Founded in 1995 by Patrick Louisy, a recognized biologist who is passionate about seahorses, among other things, the association has developed an ambitious “Hippocampus Inquiry” program which brings together several projects such as HIPPO-ATLAS, HIPPO-THAU, HIPPO-HABITAT where everyone can contribute in its own way. The results of this research are regularly published and the magnificent work by Patrick Louisy "Hippocampes, une famille d'éccentriques" is recommended to all those who are curious by nature.
Also note the Fish watch forum, managed by the association Blue Skin which is a participatory observatory collecting the many marine observations in Europe and in which anyone can participate.
Project seahorse: Founded and managed by Amanda Vincent, world specialist in seahorses, Project seahorse participates in research, awareness and actions for the protection of seahorses in the world. Their greatest feat of arms? The inclusion of the seahorse in Appendix II of CITES in 2002. Their site and its regular publications are a real gold mine.
Ocean obs: Ocean Obs is a sea sentinel network operating on the Atlantic coast and the cross-checked data is then shared with different scientific projects. Their participatory marine biodiversity observatory program (OBPM) essentially aims to monitor seahorses and cuttlefish in their eelgrass habitat.
An ocean of life: "A small gesture for a great cause", such is the motto of the association Founded by René Heuzey. The objective is simple, to raise public awareness against pollution by our daily waste and to encourage citizen action by organizing collection campaigns on our beaches and seabed. An essential objective ensured by a strong media presence, thus their blue mesh bag, used for waste collection, is known to all.
Longitude 181: Founded by François Sarano and his wife in 2002, Longitude 181 is now recognized around the world. On the strength of its ability to communicate, the association plays an essential role, that of raising awareness, and the various Chartres that it has established against divers and boaters are now adopted and displayed everywhere.
There are many other initiatives and projects from which each will derive a different sensibility, but all deserve our support. Let us act now, together and preserve what nature offers us most incredible ...
A Breton diver above all, I do not hesitate to leave my land of spray to discover the small world that populates our oceans.Wonder being the most direct route to sensitivity, I needed a way to share this universe that so many earthlings ignore.This is how I discovered underwater photography and long immersions ...Find her instagram here.