MARINE LIFE

 

THE SEA TURTLES OF CRETE

 

The Loggerhead Sea Turtle, known by its Latin name 'Caretta-caretta', the name is derived from the massive block-like head and broad, short neck. It is the only turtle in the genus 'Caretta' and is listed as a threatened species it is also the only marine turtle nesting in Greece and the Mediterranean, the females returning each year to the same beaches they were born on, to lay their own eggs. Zakynthos in the Ionian Islands is the most important hatchery in the Mediterranean where about 2,000 nests are laid annually, and  4,000 sea turtles have been tagged since 1982.

  

 

Sea turtles resemble land turtles in form but their limbs are swimming paddles rather than walking legs and they cannot withdraw into their shells. Sea turtles have existed for more than 175 million years. Today, there are seven species of sea turtles in the world, belonging to five classifications. The loggerhead is characterised by a large head with blunt jaws, they are one of the largest of the hard-shell turtles, with the adults weight ranging between 200 to 350 pounds, but larger specimens have been reported. 

Sea Turtle with Fishing Hook in its mouth

 
The limbs are paddle-shaped and each have two claws. As with all sea turtles, the adult make has a long tail, whereas the females is much shorter. Sea turtles belong to the reptile family, cold-blooded vertebrates, laying white leathery looking eggs. The turtle's main diet is shellfish, crabs, fish, and other marine animals including jelly fish. Sometimes they can mistake plastic bags for jelly fish and have been known in this land of the ubiquitous plastic bag to choke on them.

After initial surveys carried out between 1989-1990, Sea Turtle Protection Society of Greece identified significant numbers of nests along some of the beaches of Crete. Nest protection and monitoring as well as public awareness activities were started in 1990. Ever since, ARCHELON has been running a project in the three most important nesting areas of the island, along the northern coast of Hania where on a total of 13km of beach, 116 nests have been monitored, 385 nests, the largest, in Rethymnon approx 10km of beach and 58 nests around the Bay of Messara on the Southern coast on a total of 8km of beach. Totalling some 33km of beach and approx 559 nests annually. Monitoring and excavation data give an estimated annual production of 37,000 hatchlings.

In many areas some of the beaches are so far untouched by human development and therefore offer the turtles a safe place to nest, secluded from the outside world. However, in the past 20 years tourist development has been encroaching into these untouched nesting habitats.  ARCHELON monitored and recorded the feeding and breeding behaviour of the turtles nesting on these sandy beaches. Incorporating a conservation programme to promote the protection of these main nesting areas from any rapid development, most are already stable and therefore offer the females a safe nesting ground to lay their eggs.  With the data collected its being used to produce a conservation plan in an effort to protect the turtles and their habitats throughout the island of Crete.

  

All nests identified on daily morning surveys are assessed as to the suitability of the location. If it is decided that they are not in danger of inundation or destruction they are left in place and a metal cage is placed on top of them. The cages identify the location of each individual nest and protect it from accidental destruction by beach users. (see opposite picture). They bear a sign in three languages (Greek, English and German) informing people of their purpose.

 

The nesting season is June to August during this time the beach is monitored nightly from 10.00 pm. to 6.00 am. where every emerging turtle from the sea is recorded. This includes the length and width of the shell and the health of each female. The nest position, and the number of eggs in each clutch, each female can lay between 80 to 180 eggs. The tag numbers are recorded and turtles without tags are marked. After an incubation period of around 55-60 days, the hatchlings emerge late at night or early hours of the morning and make the precarious journey to sea. These tiny creatures sense the right direction in which to go because they are attracted to bright light. At night, the sea is the brightest area with the moonlight reflecting off the water. Each hatchling makes this journey often precarious over lots of obstacles such as sandcastles, holes and the chance of being eaten by seabirds, large crabs and even rats on shore , whilst at sea they become victims of other inhabitants of the deep. This this mad dash is two fold, the first to strengthen their muscles and the other survival. Those lucky to escape - 1 in 1000 - can reach maturity in 12 to 30 years. 

The loggerhead is found in temperate and subtropical waters, worldwide, with major nesting beaches in eastern Australia, Sultanate of Oman, and the south-eastern United States. However, in the Mediterranean the population  is severely reduced and areas where it used to breed, such as Italy, Israel and Syria it has all but disappeared. Loggerheads have been known to migrate over long distances with some tagged specimens recaptured up to 1,500 miles from where they were released. 'Caretta caretta' care found hundreds of mile out to sea, as well as inshore in bays and lagoons, reefs, rocky places, inlets and ship wrecks are all used as feeding areas.

It is hoped that with the help and support of the local fisherman and compensation for any damaged nets, the support and co-existence of people and turtle, locals and tourists alike is giving valuable support and is essential in the protection of these nesting grounds.

 

ARCHELON operates four seasonal and portable information stations throughout Crete.  ARCHELON volunteers run these stations during the entire summer season, providing information and distributing leaflets to visitors. These stations are located around the old harbour in Hania, next to the GNTO office in Rethymnon and in the south coastal resort of Matala. They are open daily from May 15 to October 10, operating hours 10:00-14:00 & 18:00-22:00.

A First Aid Station and Environmental Station started operating in August 2005, in the Municipality of Arkadi, Rethymnon. The Station operates in the context of LIFE-Nature project for the reduction of the mortality of sea turtles at sea and is located close to the nesting beach of Rethymnon, which is one of the most important nesting beaches of the sea turtle 'Caretta caretta' in the Mediterranean.
 

 

THE MEDITERRANEAN MONK SEAL

 

FACT: The Mediterranean monk seal is the No1 endangered marine mammal in Europe. It is also in the top 6 of the most critically endangered mammals list on earth and in the top 12 most critical list of endangered animals WORLDWIDE.

 

Centuries ago seeing The Mediterranean Monk Seal was an everyday event, found in great numbers emerging from the sea and stretched out lazing on the sandy shores. The Mediterranean seal, its Latin name 'Monachus monachus' today is the number one species under threat of extinction in Europe. The other two 'Monachus' species are the Hawaiian monk seal 'Monachus schauinslandi', also critically endangered, and the Caribbean monk seal 'Monachus tropicalis', is considered extinct, with the last recorded Caribbean Monk Seal dying in the early 1950's.

 

The Mediterranean Monk Seal once lived in colonies along the coasts of the Black Sea, the Mediterranean, and the Atlantic Ocean from Portugal to Senegal. But today they are one of the rarest mammals in the world. Only around 500 remain, scattered between Turkey, Greece, Morocco, Western Sahara, Mauritania, and the Madeira Islands. With only 200-250 living and breeding in Greek waters it is the largest global population of the species.  Diminished into two surviving areas, one habitat is the Atlantic coast of northwest Africa and the other, here in the waters of the Mediterranean. Where they remain still the most endangered mammal in Europe. Today, the remaining seals seek refuge in inaccessible caves along remote coasts with cliffs. Eking out a precarious existence in isolated pockets off the east end of Crete.  Around 300 monk seals - the largest population - live in the Aegean Sea, the part of the Mediterranean bounded by Turkey to the east, mainland Greece to the west, and the island of Crete to the south. 

 

They survive in these waters with another threatened and endangered species, the sea turtles 'Caretta caretta'. The surviving monk seal population in Greece has decreased to seriously low levels. Apart from the common hostility to these marine creatures from fishermen, the disruptive effects of two world wars and the now rapid progress of industries and the associated pollution, the most significant factor in the species’ decline is the accelerated increase in mass tourism. This along with tourist developments next to the coastlines inevitably brings the increasing disturbance and destruction of the natural habitats. Not to mention the rapid increase in pleasure and motorboat activities which, during the breeding and weaning seasons, are regarded as a major threat to the species. This reckless pursuit of enjoyment by an inconsiderate minority can cause fear, abandonment of the pups and sadly, in some cases, death. 

 

Believe it or not in ancient Greece, Monk Seals were protected. Their display of great love for sea and sun placed them under the guardianship of the gods Poseidon and Apollo. These animals were mentioned by Homer and Aristotle and even depicted on one of the first coins to be stamped in 500 B.C. The fishermen and seafarers, who caught sight of the animals playing in the waves or plodding slowly on the beaches considered that to be a omen of good fortune.

Chronicled throughout history, we have all been made well aware that humans have hunted seals for their own survival for many hundreds of years. The trusting and inquisitive nature of these creatures has made them easy prey for hunters and fishermen who dispatched them instantly using spears, but when the animals were netted and clubs were used, these savage culls became a blood bath. The seals were killed mainly for the pelts that went into making of clothing, shoes and tents giving excellent protection against adverse weather conditions. The meat of the animal was consumed with the fat being rendered down for oil to be used in lamps.

Evidence has suggested that after the fall of the Roman empire the species was severely depleted. However, a decrease in its necessity, with the introduction of the more refined olive especially within the Mediterranean areas may have possibly allowed the monk seal to gain a interim recovery period, though not to original levels. During the Middle Ages trading in seal pelts once again peaked in certain regions, practically wiping out the larger colonies. For the ones that survived a hard lesson was learnt, they no longer grouped together on open beaches and rocky outcrops, but instead found refuge in caves and along inaccessible and rocky coast lines. Nowadays, pollutants, plastics and fishing lines fill the sea and ride the waves, and fishermen kill them because they believe that they steal 'their' fish. Consequently today these reclusive creatures hide so well that little information is available.

The seal 'Monachus monachus' is so called because of the flap of skin behind its head, which looks like a monk’s cowl and belongs to one of the largest species of seal in the world. Its life span is up to 40 years but today mostly only 20 if lucky, with males and females looking almost identical. Males weigh in at about 315 kg with an average length of 2.4 m. The females are only slightly smaller, weighing approximately 300 kg. Adults are generally brown or grey on the back. A white patch is common on the underside of the belly, and others have irregular mottled light patches on the stomach. The older males tend to be black. Pups are born between 88 -103 cm in length and weigh 16 -18 kg. The Mediterranean monk seal pups are born with a white or yellow patch on the stomach and have a black, woolly coat.   

The Mediterranean monk seal has been virtually eradicated from most of its original habitat by human encroachment and females now pup only in caves in remote and relatively undisturbed areas. Males and females are thought to reach sexual maturity between 5 and 6 years, although some females may mature as early as 4 years. The Mediterranean seals give birth about once a year, usually every two years. The seals are always born on land, in dark, well-protected sea-caves. The birth period last from August to December. The new-born are about one metre in size and weigh approximately 15 kilos. They will suckle for about three months and then learn to find their food for themselves.  Monk seal pups can swim and dive at about two weeks of age and are weaned at about 16-17 weeks. They need food equivalent to 5% of their body weight per day and will travel huge distances to find it. Their main diet is fish, octopus, squid and seaweed. Despite being a mammal, the Monk seals metabolism allows it to hold its breath under water for up to 15 minutes. Special muscles in the nose block off its nostrils helping it to dive down to depths of around 100 metres. Around Crete's rugged coastline there are many large sea caves and these make ideal places for these creatures to live. If you are lucky enough to see a monk seal, do not follow it or frighten it disturb any way only observe from a distance. 
 

Greek scientists, conservation organizations and wildlife authorities have developed a collaborative Greek National Program for the Protection of the Monk Seal under the coordination of  MOm/The Hellenic Society for the Study and Protection of the Mediterranean Monk Seal.

MOm, is a non-profit, non-governmental organization, which was established in 1988 by a group of biologists and researchers from the Departments of Ecology and Zoology of the University of Athens.
 

 

THE DOLPHIN

 

For thousands of years the dolphin has been a symbol in Greece that has played an important role in the cultural and artistic heritage of its people, and for them it represents an expression of freedom and beauty. No other animal on the planet has had such a magical connection with humans. Since ancient times the dolphin’s lack of aggression, sense of fun and ability to contact the deepest human emotion and spirit has become legendary. Cetaceans have inspired people since antiquity, they appear on many wall paintings, urns, coins, jewellery etc.

 

 In fact, cetaceans have been a part of the Greek civilisation for over three and a half thousand years. Furthermore, 'cetology', the field of biology which focuses on the study of cetaceans, originated in Greece. The first scientific report of these animals is 'Historia Animalium' written by Aristotle and dating back to 350 B.C. Dolphins are mammals from the whale-porpoise family known as cetaceans which scientists believe may have evolved from early land mammals that returned to the sea. Their skeletons have uncanny similarities to ours, and they have a complex language, each dolphin having a personal signature tune as unique as a fingerprint. Although they are quite large and powerful animals there have been no reports of any unprovoked attacks on man. However, many have been known to kill a shark with a single blow. Dolphins will allow people to grasp their strong dorsal fin for a ride, carry children on their backs and even leap out of the water next to swimmers. There have been numerous instances of dolphins saving peoples, from fishermen to swimmers, divers and windsurfers. In the last decade dolphins have even been used in the treatment of depression.

International Dolphin Watch, an organisation established to protect these mystical creatures, believe it is essential for the overall well being of dolphins that they be able to breed, feed and roam in their natural environment. Unfortunately through the polluting of the Mediterranean as well as the excessive fishing with the use of fine filament nets, the dolphin population has been drastically reduced and is continuing to do so in the sea surrounding Greece.  It is hoped that with the tighter environmental control and stricter regulations from the EEC and the Greek government, particularly concerning fishermen, we will once again see these magnificent animals thrive.
 

Adult Striped dolphins reach an average size of 2.2 m and a weight of 80-100 kg. Males are slightly larger than females. They are characterised by a long thinned rostrum, small and sharpened teeth, a slender torpedo-shaped body, a small and falcate dorsal fin and small slender flippers. Similarly to the Common dolphin, also in the Striped dolphin the colour pattern is characteristic for the species. Its dorsal colour varies from light to dark and to bluish grey, its sides are light grey and its belly is white. A black band begins behind the eye and extends along the flank to the anus. The light spinal blaze originates as an open V above and behind the eye, narrowing to its vertex below and behind the dorsal fin. Striped dolphins can swim very fast, often performing great leaps. 

 

As well as being found in the pelagic zone (any water in the sea that is not close to the bottom is in the pelagic zone. The word pelagic comes from the Greek word 'pélagos', which means open sea. These wonderful creatures can be found In the Mediterranean much closer to the coast particularly in areas where the shoreline descends steeply into the sea, or in a channel between two islands. Striped dolphins live in herds of a variable number of individuals, from about 20 to about a hundred animals. In Mediterranean Sea it is the most common species. They feed on fish and squid and show opportunistic feeding behaviour. Although the species is generally abundant, some populations are in danger. Between 1990 and 1992 in Mediterranean Sea a measles virus caused the death of more than 1.000 individuals. Pollution and the decline of food resources were identified as the causes starting off the infection.

 

The adult Common dolphin reach 2.5m in length and 75kg in weight. Its colouration is geographically variable. The upper side is black or blackish brown while the side presents a hourglass effect, with a tan or yellowish region making up the lower half of the hourglass. Below the dorsal fin is a typical V-shaped black or dark grey saddle with downward-oriented apex on the sides. A dark stripe connects the dark eye patch with the corner of the mouth and another connects the lower jaw with the flipper.

Common dolphins can swim fast performing great leaps. They can dive quite deep, up to about 280m, sometimes more than 8 minutes at a time. They can live both in both deep water and inshore habitats and can be often observed with bottlenose dolphins.

The species is widely spread in the free waters of all tropical, subtropical and warm temperate seas, however the Mediterranean population has declined dramatically in the last decades. In October 2003 the Mediterranean population was listed as Endangered. 
 

SPERM WHALES

 

The presence of sperm whales in Southern Crete is related to the very steep underwater cliffs that exist near the coastline. At these depths, squids on which sperm whales feed, are abundant. Research has shown that Southern Crete is the only known area in the world where females and their offspring, along with solitary males, co-exist all year round. The most plausible explanation for this unique phenomenon is that living conditions in this area are ideal for sperm whales with little threat.

   
 

The eco-volunteer programme 'Meet the Sperm Whales and Dolphins of Southern Crete' was initiated in the summer of 1999 with great success. One of the primary aims of the program is to acquaint people with the sperm whale, a most magnificent animal, not only of Greece, but also of the planet. It is not however, widely known that these peaceful giants inhabit Greek waters, people are amazed when they find out. By exposing people to sperm whales, dolphins and the Greek natural heritage, the program ultimately aspires to raise public awareness regarding the value of the natural environment and the need to protect it. Furthermore, the eco-volunteer program is the primary source of funding for the 'Cretan Sperm Whale Project'. This research project which focuses on the broadening of our knowledge and understanding of sperm whales and the monitoring of their population, would not be possible without the support of volunteers.

Visit the Pelagos Cetacean Research Institute and learn more about its activities and the ways that you can join its eco-volunteer program. 

  

The sperm whale is the largest of all 'Odontocetes' (have only one blowhole and teeth) with its average size of 18m and its average weight of 50 tonnes. Females are smaller than males about 11m. Characteristic of the species is the box like shape of its huge head (40% of the body length). The colouration is of a dark brownish uniform grey along the external part of the upper and lower jaws. The belly and the front of the head may be greyish to off-white. The body has a corrugated or shrivelled appearance. Calves are much lighter grey overall.

 

 A single blowhole is located on the left side of the front of its huge head and the spout is low and projects forward at a 45° angle. The end of the tail holds the fluke, or tail fins these are broad and triangular, straight rather than concave, and deeply notched. The narrow under-slung lower jaw contains eighteen to twenty five functional teeth, which are thick and conical and fit into sockets in the generally toothless upper jaw.

Sperm whales can dive up to 3000m in depth. Before diving they remain on the surface for 10-20 minutes, then they curve their back and draw out the big tail fins.

The social structure of sperm whales is based on a group, or nursery school, containing females and juveniles of both sexes.  Inside the social group the relation between individuals is stable and the offspring are nursed for many years. Whilst females appear to remain in their native group for their whole life, males leave their mothers once they come to age between 15 and 21 years old. That's when they form with other males, the so called 'bachelor herds'. Growing older males tend to be isolated from other individuals. Older males are usually solitary lone bulls, except during the breeding season, when they may join with nursery schools for mating.

 

Sperm whales live mainly in deeper water like the dolphins (pelagic zone) but still they can come closer ashore whenever the land drops steeply into deep water. Sperm whales feed on squid, tuna, barracuda and fish such as cod, hake, weaver fish.  Because of the commercial hunting of sperm whales due to the high value of its meat, oil and spermaceti, (see below) the species is declining. In the Mediterranean Sea their mortality rate, attributable to the high level of collisions and by  getting caught in nets and drowning, is alarmingly high.

 

Spermaceti, again coming from a Greek word 'sperma', for seed, and cetus, which was a sea Whale in Greek mythology. It is a wax present in the head cavities of the sperm whale 'Physeter macrocephalus'. Spermaceti is extracted from whale oil by crystallisation at 6 °C, when treated by pressure and a chemical solution of caustic alkali. Spermaceti forms brilliant white crystals that are hard but oily to the touch, and are devoid of taste or smell, making it very useful as an ingredient in cosmetics, leatherworking and lubricants. The substance was also used in making candles, in the dressing of fabrics, and as ointments, particularly in pharmaceutical carriers. 

 

Grinding and pressing of crude Spermaceti

Filling bottles with Sperm Oil

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