Biševo Geotrail

Check out the geotrail

The existing Biševo Geotrail, which originated in Mezoporat and lead to Polje, then Salbunara and ended in Porat, has now been added new legs from Polje to the Biševo’s highest point Stražbenica, then Potok, ending at Cape Gatula. Thus the Visitor Centre is now connected to Mezoporat, Porat, Gatula, Salbunara and Stražbenica.

Next to the trail, intended for walking and cycling, there are signposts, information panels, cycle stands, gazebos, a viewpoint with a panoramic telescope, as well as two cameras used for observing the nesting of Eleonora’s falcon. Four coastal artillery batteries had been renovated and transformed into rest areas with tables.

Next to the trails, the visitors can find a total of 25 information panels, presenting the tourist map of Biševo and the most important locations of the island, such as the Blue Cave, the Monk Seal Cave, Salbunara cove etc. They also present features of Biševo, such as its vegetation, the most important animal species – the common bottlenose dolphin, the Eleonora’s falcon and the passage birds; the speleological and geological phenomena and objects, historical buildings such as the old Biševo school, the Church of St. Silvester, the Roman well and artillery batteries, as well as the traditional agriculture of the island.

The concept of educational-thematic trails that are used for the interpretation of the natural and cultural heritage, has both an educational and recreational character. The visitors may choose any segment of the educational trail, in line with their preferences, fitness and abilities.

You have set your foot on the island of Biševo in the Vis archipelago. Biševo boasts two monuments of nature. The Blue Cave is the most attractive monument of nature in the archipelago, featuring a unique light effect that simply leaves you breathless. The other monument of nature – the longest semi-submerged cave in the Adriatic, the Monk Seal Cave, is only a mile away. With the total length of 160 metres, this cave used to be a home of the Mediterranean monk seal species, which reared their young on a small pebble beach at the end of the cave hall.

This trail describes the geological origin of the island of Biševo, as well as the cultural and natural heritage of the inhabitants of this beautiful, exotic island.

In the end of the Mesozoic or the Age of the Dinosaurs, i.e. at the beginning of the Cenozoic or the Age of Mammals, Biševo was located in a tropical belt in the middle of the ancient Tethys Ocean. Biševo was a part of a small continent located between Europe and Africa called the Adriatic Carbonate Platform. It was covered by shallow and warm sea teeming with life and numerous organisms.

Biševo’s sedimentary layers were built from numerous shells and remains of these organisms. When the Adriatic Carbonate Platform collided with Europe, these sediments were tectonically elevated, resulting in the formation of the Dinaric mountains and the present-day islands of the Vis archipelago.

The Quaternary period, when the sea level was 140 meters lower than today, was marked by dry and cold Ice Age. Strong winds carried the sand from the steppes to the surrounding hills and present-day islands. In that manner the fertile soil which yields the finest quality grape and the beautiful sandy beaches of Biševo were created.

The Blue Cave – beautiful beyond words
Inside the Blue Cave

The Viennese painter Eugen baron Ransonnet discovered the Blue Cave on the island of Biševo. On Thursday, 7th August 1884, the Viennese daily Neue Freie Presse published the article by Baron Eugen Ransonnet:  Die blaue Grotte der Insel Busi.

This article sparked a massive interest of the Austrian public in the natural beauty of the coast and islands of the Austro-Hungarian Empire. It was a sensational news story about the discovery of the natural Adriatic phenomenon – The Blue Cave on the island of Biševo.

In Ransonnet’s opinion, the beauty of this cave topped the more famous Grotta Azzurra on the island of Capri which was then considered the most beautiful sea cave in the world. As you leave behind a bright summer day and enter the dark tunnel of Biševo’s Blue Cave, you soon encounter the deep blue beauty which flashes at us from the sea, that colour which turns all objects and bodies immersed in it into liquid silver.

And you can tell with certainty that you are in a mythical place, in a temple of beauty, that you have crossed over from reality to a supernatural realm, into an inexplicable mythical ambient of a sea deity which fills us with inexplicable feelings and miraculous strength.

The newest pages in the stone “book” of Biševo island are the limestones formed during the Paleogene, the geological period dominated by mammals.

Like small pieces of rock tumbling down a snowy slope, these stone balls were formed by the sliding of the sediment down the slope of the sea bottom. Such biogenic limestone is commonly found in the central part of Biševo island and can easily be recognised by the coarse (rough) surface and nodular (“ball-like”) layers. They are easily decomposed into calcareous sand which was carried by the wind to the island’s sandy plains and the valleys during the last Ice Age.

The sand was formed of the millions of tiny calcareous shells of protozoa (foraminifera), algae, sea urchins, shells and their debris. The accumulated grains of sand in the sediment have been subsequently bound by the crystallised carbonate cement, forming solid rock – the limestone.

Stone balls from the bottom of the ancient sea
A stone ball in the nodular Biševo limestone at Mezoporat bay

Approximately 100-120 million years ago, some land plants became underwater plants again. One of such plants is the Posidonia oceanica, commonly known as Neptune grass or Mediterranean tapeweed – an aquatic plant bearing flowers and fruits, endemic to the Mediterranean Sea. The posidonia seagrass species is the most widespread endemic sea flowering plant of the Mediterranean. It was named by the famous Swedish botanist Linné, after the Greek sea god Poseidon.

Posidonia plays an important role in the ecosystem of coastal waters in multiple ways. Up to 400 various plant species and a couple of thousand animal species live in posidonia meadows. Only upon careful inspection one may notice that the seemingly empty posidonia meadows are actually habitats teeming with marine life. Posidonia’s leaves are a home to a plenitude of plant and animal species called the epiphytes (from the Greek words epi meaning “upon” and phyton meaning “plant”). They are a food source to fish, molluscs and crustaceans. Due to its elongated leaves and a developed network of rhizomes, posidonia catches sediment particles, adding to the sea transparency. In the autumn, the posidonia seagrass, also known as “lažina” in Dalmatia, protects Biševo’s sandy beaches from sand erosion. It has been estimated that Biševo island is surrounded by 200 hectares of posidonia, making up the area called “The Biševo Sea” within the ecological network Natura 2000 together with sea caves, coralligenuous reefs, sand beaches and the seabed. Just like continental forests, the posidonia meadows represent the “climax” community (i.e. the final stage in the long ecological succession) in the coastal submarine area, which produces significant amounts of oxygen crucial to life. Due to its slow growth, averaging between 1 and 7 cm a year, posidonia meadows take a long time to restore. It is therefore of exceptional importance to take all preventive measures to protect posidonia by regulating the negative human impact – by constructing the necessary sewage systems, prohibiting laying pebbles in the sea and the usage of trawl nets as fishing tools, as well as regulating the anchoring.

The Mezoporat bay on Biševo has an ecological mooring system. The boats are tied to the floating buoys in order to avoid the repeated anchoring to the seabed where the sensitive posidonia meadows are located. Throughout history posidonia was used as fertilizer, as a roof-covering material and for the construction of resting mats. In the Lazaret cave in Nice, the remains of a posidonia bed used some 10,000 years ago were found.

In the hinterland of the Blue Cave the consequences of the violent dynamics of the Earth’s crust can be seen. Due to the action of the Earth’s tectonic forces and the slow movement of large blocks of the upper parts of the crust, the rocks were fractured, resulting in the blocks moving along these fractures – flat surfaces known as the faults. Traces of tectonic movement or scraping of the Blue Cave’s block against the central mass of Biševo island’s rocks can be seen along the sleek fault plane called the paraclasis. This fault intersects the rocks so it can be traced from the southern entrance to the Blue Cave to the narrow northern passage between the shore and a small islet along which the boats with the Blue Cave visitors are sailing.

The Blue Cave was probably formed through selective erosion (abrasion) during the interaction of the tectonic (diapiric) rise of the island and the rises of the sea level after the last Ice Age. More precisely, the rocks of the terrestrial phase are softer than the surrounding carbonate rock, and that very horizon, i.e. a “page” from the stone “book” is presumably located in the level of the submerged parts of the Blue Cave. Massive waves propelled by strong southern winds crashed into the softer rocks, carving out a large hole in them – the present-day geomorphological phenomenon, the Blue Cave. These rocks are still under the influence of the strong winds and waves that carve them.

Tectonic forces and the fault plane
A photograph of the fault between nodular limestones and Blue Cave limestone block
Coexistence with the rocks
A panoramic view of platy limestones that are used on the roofs of traditional houses at Porat cove

People have been exploiting rocks since prehistoric times. On the island of Biševo there are various types of limestone which occur naturally in various forms – as massive, thickly bedded, nodular (wavy) and platy. That natural material was hence used for the construction of houses and other objects on the island.

On Biševo flatlands there is a spacious plain (Polje, meaning “field” in Croatian) with the largest settlement in this picturesque countryside, bearing the same name. The Church of Saint Sylvester is the largest building on the island, built from various types of meticulously selected Biševo stone (carved blocks, boulders and plates). The second largest building on the island is the former elementary school, the site of the future Visitor Centre. It was also made of the local Biševo stone, as are most of the other objects on the island.

The inhabitants of the island used various types of geological substrates for various crops that supported life on this distant island. Due to the specific geological substrate, the highest quality of the soil is in the Polje area, offering breath-taking views of Svetac island. The area is gorgeous in spring, when macchia turns into a floral oasis.

In 1050 a priest from Split by the name of Ivan erected a church on Biševo’s plateau and dedicated it to Pope St. Sylvester (314 – 335), the first Pope in the history of Christianity to secure Christians’ right to publicly declare their faith. Father Ivan gave the church over to the Benedictines from the Tremiti Islands. The Church of St. Silvester was built in the pre-Romanesque style, but its original shape had been changed in later centuries. At the period of the construction of the church, the Benedictines arrived to Biševo and erected their monastery in the vicinity of the church.

In the tumultuous period of battles between Venice and the Byzantine Empire over these areas, the monastery of St. Silvester on Biševo turned to Pope Alexander III for protection. On 2 May 1181, the Pope signed a privilege under which he placed this monastery. The letter begins with the Pope’s address to the monastery’s superior, abbot Urso: “Bishop Alexander, a servant of God’s servants, to his dearest son Urso, abbot of St. Silvester’s monastery on the island of Biševo and his monastic brethren, the present and future ones, for times to come.”

One of the oldest paintings of Madonna in Croatia, the Madonna from Biševo, painted in the proto-Venetian style and dating from the 13th century (1220), was preserved in this church on Biševo. The painting was believed by the locals to have miraculous powers.

The Church of Saint Silvester on Biševo
Painting of Madonna from Biševo
Peter’s essay
Peter’s essay

In 1921, the first elementary school on Biševo was founded in a private family home in the village of Porat. In 1937, the inhabitants of Biševo built their own school building in the village Polje. The school was operational until 1961, when it had to be shut down due to a small number of school children. Before World War 2, Biševo had 350 inhabitants, in comparison to the 2011 population census which registered only 11 permanent residents on the island. Many of its former residents permanently emigrated to the United States, mainly to San Pedro in California, or to Australia.

A pupil’s notebook from 1956 was found in this building. In it was an essay on the subject of their native island:

Biševo, 14 February 1956

Fifth school essay

My village

“My village is called Biševo, it is in the middle of the Adriatic. People here are farmers and fishermen. My village is surrounded with hills and a small forest. The houses are scattered around and people say it’s quite desolate. My village has no railroad and power stations, no cinemas or theatres. We don’t get the big steamboats as in big cities. My village is small and it has one world-famous cave.”

These words were written down by a little boy named Petar on a cold winter morning of 1956. A third-grader, he wrote about his island in the middle of the Adriatic, known for its Blue Cave.

In 1990, the town of Komiža joined forces with the University of Zagreb, initiating the restoration of the Biševo school building with the idea it would eventually house an international research centre. This happened around the time when the island of Vis and its archipelago ceased being an isolated military zone after 45 years and when the first foreign tourists were allowed to the island. A hope flared up that this historically unique moment could be used to start a sustainable development programme on this desolate archipelago. This project was paused by the onset of the Homeland War but the idea remained alive, only to be realized 28 years later, with the Biševo school building undergoing renovation that will transform it into a new Visitor Centre on Biševo.

At the end of the Age of Dinosaurs (the Cretaceous), the wider area of the island of Vis surfaced from the sea. Once exposed, the limestone rocks slowly became subject to the new, terrestrial conditions. Just as present-day muddy rains contain desert dust from the Sahara, back then the openings in the paleokarst were filled with the reddish-brown dust. Today that dust is found in the form of reddish-brown petrified soil.

Acting as a time capsule, the ground has preserved animal bones as a memorial of the times when, instead of the present-day islands of the Vis archipelago, there was once a large island in the middle of the Tethys Ocean. Dinosaurs, crocodiles and other terrestrial animals inhabited the island.

The sea life flourished again after the sea flooded this area once more during the Paleogene. During this period an entirely different type of limestone rocks were deposited compared to the limestone rocks of the Cretaceous. These new rocks took the form of biogenic limestones, not reddish-brown but light-brown in colour.

The terrestrial phase on the island in the middle of the ocean
A photograph of the reddish deposit from “terrestrial phase” in the cutting of new road
The aeolian sand from the Ice Age
A vineyard covered in the Ice Age aeolian sand

In the most recent geological period – the Quaternary, you would not be able to reach Biševo by boat, but by an SUV. During the ice ages of that period, the climate was dry and cold and the sea level was 140 meters lower than today. The Adriatic was not seabed but a vast steppe landscape and the islands were scattered peaks of the hills. The steppe landscape was dominated by sand which the winds scattered over the surrounding hills. The present-day sand fields are just erosive remnants of those larger sandstone roofs. Such specific soil has enabled the cultivation of high-quality grapevines and has become home to a numerous population of land snails. Most of the sand washed by the floods ended up in the valleys that were submerged by the sea following the sea levels rise after the last Ice Age. Due to this reason, some of the most beautiful sandy beaches of the Vis archipelago are found on Biševo island: Porat and Salbunara.

He was born on Biševo island in 1893. In order to avoid serving the Austro-Hungarian army, he decided to go to the USA in 1913. He boarded the steamboat Martha Washington in Trieste and, after an eighteen-day journey, disembarked in New York without knowing a word of English and carrying only $22 in his pocket. Nevertheless, arriving to the States, Pavao Martinis possessed enormous fishing experience gained in his homeland, fishing with his father since childhood. He arrived to Astoria, Oregon. Having heard that there were fishermen from Komiža in Tacoma, he decided to find them. It was a pioneering time of fishing in Alaska, when fishing boats were still powered by sails and oars. They fished salmon under horrible conditions.

Pavao Martinis went down in history of American fishing not only because of the record catches of salmon in Bristol Bay and the Bering Sea, but also as the first American fisherman who discovered salmon in the rich and dangerous waters of the Aleutian Islands. In 1956, the US President Dwight D. Eisenhower awarded him the title King of Salmon for his fishing endeavours.

Pavao Martinis
Pavao Martinis
The “Stone book” from the Age of Dinosaurs
The “Stone book” from the Age of Dinosaurs

Salbunara, one of the three coves on Biševo, was named after the Komiža expression for sand – “sarbun”. On the north-western edge of the island an entire epoch of the Earth’s crust emerged from the sea depths in the form of the “books”. The collision of the Adriatic Carbonate Platform and Europe resulted in a tectonic rise that shaped the Dinaric mountains and these hills, present-day islands of the Vis archipelago. Due to this reason, spectacular cliffs can be found all along the coasts of these islands. Each “page” of this geological “book” tells us a thousand-year-old story. The rich records of this “Poseidon’s Library” are found all along the Salbunara Bay, and are decorated with fossilized ornaments depicting the contours and textures of prehistoric life. Carbonate sludge and sand, petrified (lithified) later on into a layer of solid limestone rock, formed from ground parts of fossil shells.

In the lagoons of the then Adriatic Carbonate Platform, a group of bivalve molluscs called the rudists lived burrowed in the muddy bottom of the tropical sea. An asteroid impact some 66 million years ago sealed the fate of these protozoa, together with the dinosaurs. The fine sand was formed of the rudists’ and snails’ shells in the period when the sea level rose. It was swirled around by the sea currents, creating sandbars.

The legend of Martin Bogdanović, a man from Biševo island, tells us how one day Martin was busy tilling his vineyard, breaking the handle of the hoe in the process. He was in a dilemma whether to fix it or simply leave to America. He opted to toss the hoe and go to America. He had just finished his service in the Austro-Hungarian Navy and was free to leave his homeland.

He became a fisherman in San Diego. Having saved some money from fish trading, he decided to establish a fish-processing factory in San Pedro in 1917. But in order to be able to organise offshore fishing, he had to find a way of preserving the freshness of the caught fish. Book The Port of Los Angeles states that Martin Bogdanović is the innovator who first used crushed ice to preserve fish on a fishing ship. This invention allowed him to fish in the vast Pacific Ocean. The success of his cannery was based on the experience of immigrants from his island whom he employed in his factory. Coming from a poor country, Martin Bogdanović came to a land that offered opportunity of success to the competent and the courageous. Thus, a poor fisherman from Biševo island became the greatest name of American fishing industry.

Martin Bogdanović
Martin Bogdanović
The endangered sea daffodil (Pancratium maritimum) with white blossom
The endangered sea daffodil (Pancratium maritimum) with white blossom

The coasts of the island boast a number of interesting geological forms, extinct molluscs from the Age of Dinosaurs, as well as lithified sandbanks built of millions of ammonites. The Salbunara sands are home to the rare and endangered species, the sea daffodil (Pancratium maritimum), which is not to be picked. The upper Salbunara sands are home to an abundant snail community and sand vegetation with the stenoendemic species, the woodruff (Asperula staliana), that can be found only on Biševo island. It is accompanied by the prickly dropseed (Sporobolus pungens), the critically endangered cogon grass (Imperata cylindrica) and the rock rose (Helianthemum jonium), only recently discovered in Croatia.

Big wildfire of 2003 that engulfed more than three-quarters of the island had a major impact on the forming of the current vegetation cover of Biševo. Only the northernmost part of the island was spared. Thus, the island is currently dominated by the rosemary (Rosmarinus officinalis) and the Mediterranean Heather (Erica multiflora) garrigue. Before the fire, the south part of the island was covered in the natural Mediterranean evergreen forest of the holy oak (Quercus ilex). Today, only the forest of the Aleppo pine (Pinus halepensis) has grown on some locations. So far, a total of 485 plant species have been recorded in the terrestrial flora of Biševo island. The island boasts 43 plant species that belong to various categories of endangered species, 88 protected plant species and seven endemic species. Although to a lesser extent, Biševo vegetation is also represented by the cultivated scenery, mostly covered in vineyards, which once dominated the island.

Biševo vegetation
Bushes of rosemary (Rosmarinus officinalis) in Polje settlement
Passage birds
Small passage birds such as the European sand martin and the barn swallow fall prey to the Eleonora’s falcon

The Mediterranean Sea and its bordering seas pose an obstacle for bird migration, so the birds use islands along the way, especially pelagic islands, to rest. Biševo is one of these islands. The best time of the year for bird watching on Biševo is autumn, because the autumn migrations are slower and the birds stay at way stations for a longer time. Nevertheless, one should bear in mind that different species migrate at different periods of the year, so the “autumn” begins already in the second half of July, lasting until mid-November. Thus, the autumn bird migration across Biševo and other pelagic islands over tens of thousands of years actually created an entirely new ecological niche, to which a new species, Eleonora’s falcon, adapted throughout the years of evolution. Read more about the Eleonora’s falcon on the panel number 25.

Starting from 2007, the Blue World Institute carries out scientific research of the bottlenose dolphins in central Adriatic. Numerous schools of dolphins have been observed in the area ahead of you. Gaze at the sea and try finding a school of dolphins yourself! Several hundred individuals live in the wider Biševo area, so you may notice Kulfor, Napuhavac or Babalina, who owe their names to local terms for the species, as well as centuries-old co-existence of people and dolphins in the Vis archipelago. If you visit the island in the spring or early summer, you will get the chance to see the new dolphin calves swimming next to their mothers. Waters immediately surrounding the island and representing an important habitat for those animals have been declared a designated protected area under the Natura 2000 ecological network in order to ensure favourable conditions for the survival of the animal community.

The common bottlenose dolphin
A common bottlenose dolphin (Tursiops truncatus) dives out of the sea near Cape Biskup on Biševo
Biševo geology
A geological map of Biševo showing the geological and geomorphological (speleological) sites

The creation of the two most prominent caves, the Blue Cave and the Monk Seal Cave, is related to the tectonic processes that determined the orientation of the caves (the Blue Cave fault, the Biskup fault), while the erosion and corrosion processes expanded and shaped their passages. The creeps in the southern Trešjavac cove have also been formed by the tectonic processes, probably by rising of the salt diapir. In the north of Biševo, the elevated and sloping deposits of the former Adriatic Carbonate Platform form a stone book called Libar, which keeps records from the Age of Dinosaurs. Significant surfaces of the island are covered in thin, up to 10 m thick cover of aeolian sand, which has been deposited by the wind, as its name suggests (Aeolus, from Greek: Αἴολος, Aiolos, the Greek God of wind). The greatest deposits of aeolian sand are found in Salbunara and Potok.

Throughout the history, the seas of Biševo have been a source of food for the island’s inhabitants, while today they are the source of income for the entire community of the Town of Komiža. Should there been no Blue Cave as the most recognisable sea phenomenon of the entire story, there would have been neither the Visitor Centre nor the panel you are currently reading. The two most prominent semi-submerged sea caves, the Blue Cave and the Monk Seal Cave, are the most famous tourist attractions of the central Dalmatia. Nevertheless, Biševo waters hide even more valuable sea treasure. You can read about posidonia habitats on the panel no. 4 above the Mezoporat and about the aeolian sands of the beaches on the panel no. 15 at Salbunara beach, while the story about the deepest parts of Biševo, the coralligenous reefs named after the red algae of Corallinaceae family is kept for the top of Stražbenica. Those deep rocks are overgrown with corals such as the gold coral (Savalia savaglia) and the small polyped gorgonian (Paramuricea clavata), while the red coral (Corallium rubrum) lives in the greatest depths and in the hidden crevices. The shallower reefs in the tide level are covered in the algal pavements mainly constructed of the  Lithophyllum byssoides algae, which serves as an excellent indicator of the median sea level.

The coralligenous undersea world
The seabed of the southern cape Gatula
The palaeogeographic reconstruction of the south Adriatic area during the last glacial maximum.
The palaeogeographic reconstruction of the south Adriatic area during the last glacial maximum.

The composition and the shape of the grains of sand (predominantly grains of carbonate rocks, as well as extra small quantities of minerals from igneous rocks) together with their structure, show that these sands formed in the dry climate conditions. In addition, the fossils of the Quaternary land snails that lived in the arid and relatively cold climate some 25,000 years ago were found in the sands. At that time, the northern hemisphere was predominantly covered in ice and the level of the Adriatic Sea was some 120 m lower than today. Consequently, Biševo was only a hill in lowlands, influenced by big rivers Cetina and Neretva that carried material from the distant Dinarides. The wind carried such material, including the material formed by the erosion of small local islands built from igneous rocks, to hills such as Biševo.

Next to the villages there are vineyards and small areas of arable land covered in orchards and vegetable gardens. Fruit cultures grown on the island comprise vineyard peaches, nectarines, sour cherries, plums, olives and citrus fruit. There is a saying: “Praise all wine sorts, but cultivate plavac”. The autochthonous Croatian grape variety plavac mali is the most important variety of the central and south Dalmatia. As it is strong, it is often called “the wild wine”. Its special taste comes from the aeolian sand, the high-quality substrate it thrives on. The Plavac Mali wine is the first wine to receive the protected geographical indication in the Republic of Croatia. Due to its characteristics, the Biševo Plavac was a very popular wine on the European market in the end of 19th and the beginning of the 20th century. In that period, the outbreak of phylloxera (Dactulosphaira vitifoliae) struck Europe, destroying almost all European vineyards. Luckily, the phylloxera has difficulties developing in sandy soil, so vineyards of Biševo survived the European wine crisis.

Sketches of Smokvina grotto and Jezera grotto on Gatula
Sketches of Smokvina grotto and Jezera grotto on Gatula

Smokvina grotto, originally called “grotto of Gatula” got its name after a big fig tree growing from its opening. The diameter of the opening averages 7 m and the furthest and the deepest SW part of the grotto ends in the impassable narrowing, buried in deposits, suggesting that the grotto was even deeper in history. The second grotto on Gatula, Jezera, is located across the macadam road, some 50 m from Smokvina grotto. It has two entrances, the cave-type entrance and the grotto-type entrance. A few thin stalactites (called the macaroni pasta) are visible on the ceiling of the main cave hall, while following the creeps there are bigger speleothems – primarily calcite formations, stalagmites and stalactites. The 29 m deep Jezera grotto is the deepest grotto discovered on Biševo island so far. It belongs to the habitat type 8310, so the public is banned from visiting the grotto. Protected Chiroptera bats inhabit the grotto. It is the typical habitat (locus typicus) of the diplopoda class centipede (Eroonsoma Adriatica), first described in 2003.

A total of 74 artillery batteries existed along the eastern shore of the Adriatic Sea, with 31 located on the mainland and 43 on islands. The island with the largest number of batteries was Vis (7), followed by Korčula and Lošinj (4 each), then Veli and Mali Brijun, Cres, Žirje, Veli Drvenik, Hvar i Mljet (2 each). A battery is an artillery military unit consisting of artillery weapons. It consists of 50-60 soldiers and 3-6 artillery pieces. It can serve as an air defence, coastal artillery defence etc. There is a stationary artillery battery with four cannons at cape Gatula. Fortification objects are dug in beneath the surface. Masking of the open section of the gun position facilitated the camouflage of the battery into the environment. The illustration shows the sketch of the mines organised in a manner that allowed the soldiers to spend longer periods of time underground. The inventory of the Adriatic coastal artillery dating from 1948 states that the Biševo coastal artillery battery had four 80mm cannons of the Czech origin, of Škoda brand, with a total of 5088 pieces of ammunition.

A monk seal pup
A monk seal pup

The only Mediterranean seal, known in the area as “morski covik”, is currently believed extinct in the Adriatic Sea. Today, the Mediterranean monk seal abides only in the NE Mediterranean Sea, the Cabo Blanco peninsula in West Sahara and the archipelago of Madeira. The monk seal was last seen on Biševo in 1964, when a fisherman killed it. The genetic research revealed it was an adult female. The northern, narrower and less passable section of the 160 m long Monk Seal Cave ends in a small pebble beach, ideal for the monk seal to raise their young. The entrance to the cave is impressive, featuring a big, ribbed fault plane (paraclasis), resembling huge, stone sliding doors, the so-called tectonic entrance, some 27 m high and 7 m wide.

Eleonora’s falcon (Falco eleonorae) primarily nests in the Mediterranean and the pelagic islands. The wider area of the Vis archipelago, including Biševo island, is one of such areas. The largest number of nests can be seen in the south of the island, surrounding the Trešjavac cove. There are two interesting facts pertaining to Eleonora’s falcon – its unusual preference for the pelagic islands and the time of its nesting – summer and early autumn. All other birds nest in the spring. Why is that so? The animal communities are synchronised and intertwined in a miraculous manner, with each species filling its niche. Thus, Eleonora’s falcon – a small bird of prey feeding on small birds – set its reproduction in the time and at the location of the highest concentration of small birds which they bring to their hatchlings – at the pelagic islands in the time of autumn migration. And then, when the young birds spread their wings in October and November, these falcons slowly head south, all the way to Madagascar, where they spend the winter.

Eleonora’s falcon with a nest of hatchlings on a rock
Eleonora’s falcon with a nest of hatchlings on a rock