Zakynthos Boat Trip

A Zakynthos boat trip sails along the coasts of Zakynthos, an island in the Ionian Sea off western Greece. The trip is one of the Greece Tours on Greece Ville, listed with the other Ionian Islands tours and Greece boat tours.

This post covers the Ionian Sea, how its sea floor formed, its currents, why the water is so clear, its corals and sponges, and the seabirds of the cliffs.

The fish, how the sea is kept clean, earthquakes at sea, sea warming, the best months and common questions come last. The sections include Zakynthos boat trips that can be booked online.

What is a Zakynthos boat trip?

A Zakynthos boat trip sails the Ionian Sea off western Greece. Kefalonia lies 15 km north of Zakynthos. The Strofades islands lie about 44 km south-southeast of it. The Ionian Basin, a deep and narrow ocean basin, stretches south of Italy, Albania and Greece.

The International Hydrographic Organization sets the western edge of the Ionian along the east coast of Sicily. The edge continues along the south-east coast of Italy.

A Zakynthos boat trip sails a sea whose eastern limit follows the mainland coast to Cape Matapan. Its northern limit starts at the mouth of the Butrinto River in Albania. It then crosses Corfu to Cape Santa Maria di Leuca in Italy.

The Strait of Otranto links the Ionian to the Adriatic and is less than 72 km wide. Under the strait, the sea floor rises to the Otranto Sill at about 780 m deep.

To the west, the Strait of Sicily is about 145 km wide. It separates the eastern Mediterranean from the western Mediterranean. Where it meets the Ionian, south of the Malta Bank, a sill lies 560 m deep.

A Zakynthos boat trip crosses part of the eastern Mediterranean, which covers about 1.65 million km². A shallow ridge between Sicily and Tunisia splits it from the western Mediterranean.

• Messina: The Strait of Messina links the Ionian to the Tyrrhenian Sea and narrows to 3.1 km.
• Depth: The Strait of Messina is only about 250 m deep at its deepest point.
• Kyparissia: The Gulf of Kyparissia curves along the western Peloponnese between Cape Katakolo and Cape Konello.

How did the sea floor form around a Zakynthos boat trip?

A Zakynthos boat trip crosses a sea floor shaped by a sinking plate. Beneath the Ionian Islands, the African plate began to sink about 4 million years ago, in the Pliocene. Africa and Eurasia move toward each other by only about 5 mm a year.

The Hellenic Trench begins near the mouth of the Gulf of Corinth and curves to the south. From the Kefalonia fault zone to south of Crete, it forms a line of deep basins. Underwater rises split these basins.

Sediment fills the trench below a Zakynthos boat trip and hides its main fault scarp from view. Seismic scans trace the sinking slab down to 410 km deep.

In the western part, the sinking slab dips about 30° between 20 and 100 km deep. Below that, it dips 45° down to 150 km. More than 1,500 km of old Neotethys ocean floor has sunk along this zone or its earlier versions.

The Mediterranean Ridge is the fastest-growing accretionary complex in the world. An accretionary complex is a pile of sea-floor sediment scraped off a sinking plate. The ridge’s thick sediments rest on Neotethys crust thought to be Jurassic.

The Malta Escarpment is 290 km long and up to 3.5 km high. Its 45° slope makes it one of the steepest sea-floor features. More than 500 canyons cut it, and the largest, Heron Canyon, runs 100 km.

• Fault: The Kefalonia fault zone is thought to reach 15 km down into the Ionian Abyssal Plain.
• Basement: The Ionian Abyssal Plain rests on a Mesozoic basement pushed down farther east.
• Tethys: One view holds that the Ionian Basin is a remnant of the ancient Tethys Ocean.
• Salt: Salt layers more than 3 km thick once built up on parts of the Mediterranean floor.

A Zakynthos boat trip sails a sea refilled by the Zanclean flood, possibly about 5.33 million years ago. The likeliest route for the water into the Ionian was the Noto Canyon off Avola, Sicily. The spill formed a waterfall about 1.5 km high and left sediments up to 900 m deep.

Which currents move the sea of a Zakynthos boat trip?

A Zakynthos boat trip sails over layered currents. In the top 200 m of the Strait of Sicily, Atlantic water flows east. Salty Levantine Intermediate Water flows west beneath it. Deep Adriatic water spills over the Otranto Sill into the Ionian.

One branch of the Atlantic water, the Atlantic Ionian Stream, runs eastward along the Sicilian coast. Levantine Intermediate Water forms off the coasts of Turkey. It flows west along the Greek and south Italian coasts.

Below a Zakynthos boat trip, the layer from 50 to 600 m deep is mainly Levantine Intermediate Water. Its high salt content helps deep water form in the southern Adriatic and the Gulf of Lion.

Cold winter winds such as the Bora stir the Adriatic and form deep water. This Adriatic Deep Water spills over the Otranto Sill. It forms the main part of Eastern Mediterranean Deep Water.

In the Ionian, this deep water hugs the western continental slope. After very cold winters in the mid-1990s, the Aegean briefly became the region’s main deep-water source.

The North Ionian Gyre is a large ring of current. In its clockwise phase, low-salinity Atlantic water reaches the Ionian and the Adriatic.

• Gyre: The North Ionian Gyre turns anticyclonic, which means clockwise, in its commonest phase.
• BiOS: The Adriatic-Ionian Bimodal Oscillating System, or BiOS, drives the flips of the gyre.
• Depth: The reversals of the gyre involve about 2,000 m of the water column.

A BiOS phase change comes about every five years, at irregular times. After the harsh winter of 2012, the gyre switched to clockwise in late spring 2012. In June 2017, surface salinity above 39.0 appeared in the northern Ionian, south of the Strait of Otranto.

What makes the water clear on a Zakynthos boat trip?

A Zakynthos boat trip crosses clear, low-nutrient water. Offshore Ionian waters recorded Secchi depths of 23.0 to 24.0 metres. A Secchi depth is how far down a white disc stays visible. Chlorophyll-a there measured only 0.05 to 0.1 micrograms per litre.

The Atlantic supplies nutrient-poor surface water through the Strait of Gibraltar into the Mediterranean. Dense salty water formed in the eastern Mediterranean flows outward and carries nutrients away. This exchange limits suspended plant material in the sea.

About 75% of the world’s oceans are low-nutrient, low-chlorophyll regions, and the Mediterranean is one of them. Wind-blown dust still brings iron, which can boost plant growth in the Mediterranean Sea.

Plant growth averages 0.16 grams of carbon per square metre a day in the eastern Mediterranean. Near Gibraltar, the figure reaches about 0.25 grams. The lower eastern figure reflects limited nutrients.

In nutrient-poor Mediterranean water, over half of plant growth happens in the deep chlorophyll layer. Prochlorococcus, the smallest known photosynthetic organism, measures 0.5 to 0.7 micrometres and dominates these seas.

A Zakynthos boat trip floats above water where, at 10 metres down, only 16% of surface sunlight remains.

• Clarity: Greece counts good water when Secchi depth reaches at least 6.6 metres.
• Nutrients: Greece sets good status at 0.53 micrograms of chlorophyll-a per litre.
• Coasts: Ionian coastal stations recorded Secchi depths from 9.47 to 11.29 metres.
• Exceptions: Greece rates Ionian waters good for nutrients, except poorly flushed Amvrakikos Gulf and Navarino Bay.

A 53-metre eastern Mediterranean Secchi depth ranks among the deepest readings on record. Pure water has a theoretical Secchi depth of 70 to 80 metres. Italy averaged 30.32 metres in 1865 and 16.41 metres in 2023.

What corals and sponges live along a Zakynthos boat trip?

A Zakynthos boat trip passes corals, gorgonians, algal reefs, sponges, urchins and starfish. Pillow coral and pig-tooth coral live only in the Mediterranean. Algal reefs called coralligenous formations grow from 10 to 140 metres deep. The EU protects them as habitat type 1170, Reefs.

Cladocora caespitosa, called Mediterranean pillow coral, has lived in the Mediterranean since the Upper Pliocene period. It is common on rocky seabeds from shallow water down to 60 metres deep.

The pig-tooth coral, Balanophyllia europaea, is a solitary Mediterranean coral measuring 4 to 6 cm wide. It stays in bright water down to 50 metres because partner algae need sunlight.

A Zakynthos boat trip can pass yellow gorgonians in the Ionian Sea, chiefly between 10 and 30 metres. The colonies reach 150 metres on rare occasions. The violescent sea-whip forms red fans up to one metre high. Its colonies can live well over 50 years.

These algal reefs grow where 0.005% to 3% of surface light reaches the seabed. Growth measures 0.006 to 0.83 millimetres per year in the north-western Mediterranean.

A Greek survey mapped 906.85 square kilometres of Ionian seabed. Coralligenous formations covered 75.92 square kilometres of it, or 8.37%. A Greek model predicts high formation chances in the Zakynthos–Kefalonia Straits.

• Zakynthos: Habitat 1170 covers about 428 hectares of site GR2210001 on the west and north-east coasts.
• Red coral: It grows 10 to 300 metres, but fishing has cut back colonies above 50 metres.
• Sponge: Petrosia ficiformis is purple-brown with cyanobacteria and white without light.

The orange-red sponge Crambe crambe can cover one square metre of rock at 5 to 30 metres. The violet sea urchin reaches fifteen centimetres across, with purple or white spines. The purple starfish ranges from red to orange and can show brown spots.

A Zakynthos boat trip can pass the noble pen shell. In December 2019, the IUCN listed it as critically endangered. It makes pinnaglobin, a rare protein that contains manganese. The snakelocks anemone turns dull grey when its partner algae dwindle.

Which seabirds nest on the cliffs of a Zakynthos boat trip?

A Zakynthos boat trip passes cliffs and islets used by Eleonora’s falcons, shearwaters, shags and gulls. Zakynthos has two bird protection areas, GR2210001 and GR2210004. The second covers Stamfani, Arpyia and the sea around them, about 116 square kilometres.

Eleonora’s falcon belongs to Falco, a genus named from Latin falx, meaning sickle, after its claw shape. It catches large insects such as dragonflies and eats them during its flight.

Satellite tracking of Eleonora’s falcons showed migration inland across the Sahara, rather than along the African coastline. Scopoli’s shearwater has the genus Calonectris, joining Greek words for good and swimmer.

Over 75 percent of Scopoli’s shearwaters breed on Zembra, an island off Tunisia. Its colony holds 141,000 to 223,000 pairs. In Greek, this shearwater is called Artemis.

Yelkouan shearwaters stay silent at sea, while their colonies fill with raucous cackling calls at night. The European shag has the genus Gulosus, taken from a Latin word meaning glutton.

European shag chicks hatch without down. They need parental warmth for two months before flight. Payraudeau described the Mediterranean shag subspecies in 1826; it also lives on Black Sea coasts.

• Gulls: Yellow-legged gulls honour zoologist Karl Michahelles through the name michahellis.
• Calls: The yellow-legged gull gives a loud, deep, nasal laugh unlike a herring gull.
• Audouin’s: Ichthyaetus joins Ancient Greek words for fish and eagle.
• Eggs: Audouin’s gull lays 2 to 3 eggs and reaches adult plumage after four years.

A Zakynthos boat trip can sail toward Stamfani and Arpyia, the two Strofades islands. Illegal hunting, introduced rats, disturbance and fires threaten them. The islands form a core zone of the marine park, where hunting is forbidden.

What fish swim below a Zakynthos boat trip?

A Zakynthos boat trip passes picarel and bogue in the east Ionian Sea. Boat seines aimed at them made up 88% of sampled fishing trips from 2002 to 2006. Other targets were red mullet, European squid, common pandora, chub mackerel and European pilchard.

Greek trawlers mainly work down to 400 m, leaving deeper Greek waters largely unfished. Test trawls at 300 to 500 m found fish formed 89 to 92% of catch weight.

In 2010, 150 professional fishers on Zakynthos answered a survey on seabirds caught in fishing gear. They were about 90% of the local fleet. Longlines and, to a lesser degree, gillnets caught mostly Scopoli’s shearwaters and Mediterranean shags.

Greece’s registry listed 12,101 professional motor-powered fishing vessels in 2022. Greece also had 364 registered fishing ports. About 76% of Greek fishing jobs were on boats up to 11 metres long.

A Zakynthos boat trip enters Ionian waters covered by the 2018 marine report of Greece. In that report, new alien species in Greek seas fell from 42 in 2006-2011 to 36 in 2012-2017.

• Bogue: Boops boops takes its name from Ancient Greek for “ox-eyed” because of large eyes.
• Garfish: Belone belone has green biliverdin bones, and that colour is harmless.
• Red mullet: Mullus surmuletus lives between 5 m and 409 m deep.
• Picarel: Spicara smaris grows to about 20 cm and has a black fin spot.

Common pandora, Pagellus erythrinus, carries the nickname king of the breams. It can reach 60 cm, but a typical fish is about 25 cm.

The greater amberjack, the largest member of the jack family, reaches 190 cm and 80.6 kg. The name Dentex means “with large teeth”, after the canine-like teeth of the fish. EU Regulation 2019/1241 sets a Mediterranean minimum size of 33 cm for red sea-bream.

How is the sea kept clean around a Zakynthos boat trip?

A Zakynthos boat trip sails past beaches judged by Blue Flag awards and EU bathing-water tests. Tsilivi held the Blue Flag every year from 1992 to 2018. In July 2018, Zakynthos had 18 Blue Flag beaches.

The Hellenic Society for the Protection of Nature then withdrew Zakynthos’s flags island-wide for two years. Sewage had reached the Agios Charalambos river. The 2019 list gave Kefalonia 16 beaches and Corfu 9, but none to Zakynthos.

A Zakynthos boat trip can pass Katragaki, which first won the flag in 2012. In 2020 it was the island’s single Blue Flag beach. Six Zakynthos beaches won the flag in 2021. Alykanas 1, Alykes 1 and Laganas 2 later lost it.

Five Zakynthos beaches won the flag in 2022. Agios Sostis 2 and Makrys Gialos later lost it. Seven beaches flew the flag in 2023, including Tsilivi, Bouka, Psarou and Banana Vasilikou.

A Zakynthos boat trip leaves from an island with no marina on the 2023 Blue Flag marina list. Greece tested bathing water at 171 monitoring points in the Ionian Islands region during the 2023 season.

Those Ionian points formed 169 bathing water profiles, from 1,664 profiles across Greece. The EU bathing-water list grew by 108 to 21,766 in 2023. Greece added 49 entries.

• MARPOL: The global treaty against ship pollution was signed on 17 February 1973.
• In force: MARPOL came into force on 2 October 1983.
• Annex V: The garbage annex took effect on 31 December 1988 and fully bans plastic dumping.
• Since 2012: Ships can discharge only food waste, cargo residues, wash-water and animal carcasses.

A Zakynthos boat trip sails under MARPOL Annex V. It counts fishing gear, cooking oil and incinerator ash as garbage. Fresh fish caught during the voyage do not count.

What earthquakes struck the sea of a Zakynthos boat trip?

A Zakynthos boat trip crosses waters struck by the 2018 Ionian Sea earthquake. It began at 01:54 Greek time, or 22:54 UTC. Its focus lay 14 km below the surface. Its offshore epicentre lay 45 km south-west of Zakynthos island.

The 2018 earthquake was felt in at least 8 countries, up to 800 km away. Malta, Libya and Italy were among them. Its tsunami peaked at 11 cm at Kyparissia and 8 cm at Le Castella in Italy.

A Zakynthos boat trip follows a sea watched by tsunami centres NOA in Greece and INGV in Italy. NOA lifted its alert 1 h 47 min after the quake. INGV lifted its alert after 4 h 48 min.

By 15 November 2018, 172 aftershocks of magnitude 4.0 or more had followed the earthquake. The port of Zakynthos suffered major damage. A state of emergency was declared there.

A Zakynthos boat trip crosses a plate boundary where scientists found two breaks. A small low-angle thrust slip came first. A larger strike-slip break followed in the upper plate during that earthquake.

The 18 November 1997 Strofades earthquake struck at 13:07 UTC. It lay 22 km south-west of Lithakia and 33 km deep. An earthquake at Zakynthos on 29 December 1820 set off a tsunami.

• 1867: An Ionian Sea tsunami on 19 September 1867 killed 12 people.
• 1886: After the 27 August 1886 earthquake, a small tsunami washed the coast from Filiatra to Pylos.
• Cable: The 1886 quake cut the telegraph cable to Crete about 47 km south of Zakynthos.
• Ship: La Valette reported smoke and flames toward the Strofades half an hour later.

Greece’s backbone seismic network, code HL, is run by the National Observatory of Athens. It dates from 1975. The University of Patras has run a western and central Greece network since 2000. ITSAK has over 200 stations.

How has the sea warmed around a Zakynthos boat trip?

A Zakynthos boat trip crosses the Mediterranean, a climate change hot-spot. Warming has reached the whole water column since the 1950s. From 1982 to 2019, the Mediterranean warmed by 0.38 °C per decade. The global average was 0.11 °C per decade.

A marine heatwave means sea temperatures above a seasonal threshold, the warmest 10% of past values. It lasts five days or longer. Scientists grade these heatwaves as moderate, strong, severe or extreme.

A Zakynthos boat trip sails a sea that overheated in summer 2003. Hotter air and weaker winds overheated the central Mediterranean. Less heat escaped upward, and the top 15 m took the heat. The heat changed the path and strength of the Atlantic Ionian Stream.

Average Mediterranean surface temperatures in 2015, 2016 and 2018 were higher than in 2003. That year brought the worst marine heatwave on record. The 1999 and 2003 die-offs struck more than 40 species along thousands of kilometres of coastline.

A heatwave that began in spring 2022 hit the Gulf of Taranto at nearly 5 °C above average. Warm anomalies lasted into spring 2023. That made the 2022/23 event the longest Mediterranean marine heatwave of the last four decades.

In June 2023, western Mediterranean waters ran up to 3 °C above average. In July 2023, a heatwave reached category four, “extreme”. At its 20 July peak, it covered almost the entire sea.

• Taxa: Recent mass die-offs struck 50 taxa from 8 phyla, from the surface down to 45 m.
• Sites: Of 142 monitored areas, 78% showed die-offs in at least one year.
• Cnidarians: Cnidarians were hit hardest, with 14 taxa and more than 54% of die-off records.
• Gorgonians: Paramuricea clavata and Corallium rubrum made up about 30% of die-off records.

A Zakynthos boat trip passes the coral Cladocora caespitosa. The IUCN lists it as endangered, mainly because of heatwave die-offs. Warmer water also changes when fish mature, when they breed and how fast they grow.

Which months suit a Zakynthos boat trip?

A Zakynthos boat trip suits the warm months. The sea around Zakynthos averages 22 °C in June and 24 °C in July. Late spring and September bring about 9 hours of sunshine a day. April gets about 8.

October averages about 7 hours of sunshine a day on Zakynthos, and March about 6. February and November average about 5 hours. December and January get the least sun, about 4 hours a day.

A Zakynthos boat trip can use wind data from Argostoli, on neighbouring Kefalonia. Its HNMS station stands 11 m above sea level, with data for 1970-2010. South-east winds prevail there in February, March, October, November and December.

In summer, Argostoli averages 6.2 knots of wind in June, 6.6 in July and 6.1 in August. April averages 6.4 knots, while late spring and October both average 6.0.

• Calm month: Argostoli’s mean wind speed is lowest in September, at 5.7 knots.
• Windy month: February has the highest mean wind speed there, at 7.2 knots.
• North wind: January is the only month with a northerly prevailing wind at Argostoli.

A Zakynthos boat trip meets waves much like those of the Aegean. A wave hindcast of more than four decades found very similar mean wave-height ranges in both seas. In summer, the two seas also show similar extreme wave heights.

A Zakynthos boat trip in late summer sails in waterspout season. September is the main month for waterspouts in the Northern Hemisphere. They are more frequent within 100 km of the coast than farther out.

Fair-weather waterspouts form and fade in under 20 minutes. In the Ionian, Aegean and Adriatic, tornadic waterspouts can make up half of all waterspouts. The Ionian is the second main area for medicanes, hurricane-like Mediterranean storms, with about 0.32 a year.

What do visitors ask about a Zakynthos boat trip?

A Zakynthos boat trip raises questions on ship classes, life jackets, seasickness and wave codes. EU Directive 2009/45/EC sets the classes of passenger ships. The directive sets life jackets for everyone a ship can carry, plus 5% extra.

Which ship classes serve a Zakynthos boat trip?

Under Directive 2009/45/EC, a Class A ship sails beyond the limits for Classes B, C and D. A domestic voyage starts at a port of a member state. It ends at the same or another port in that state.

How rough are the waters of Class C and D boats on a Zakynthos boat trip?

Class C ships sail where waves top two and a half metres less than 10% of the year. Class D ships sail where waves top one and a half metres less than 10% of the time.

What life-jacket rules apply on a Zakynthos boat trip?

Each person who works on board in exposed areas must get an inflatable life jacket. EN ISO 12402 replaced the older European standards EN 393, EN 395, EN 396 and EN 399. Outside the body-weight range on its label, a life jacket cannot promise a safe face-up position.

Which life jacket suits a child on a Zakynthos boat trip?

A 50-newton buoyancy aid, EN ISO 12402-5, cannot keep an unconscious wearer face up. It does not suit children under 30 kg. Over thick layers and oilskins, a 150-newton jacket can fail to roll the wearer onto their back.

Why can a Zakynthos boat trip cause motion sickness?

The vestibular system and the cochlea together form the labyrinth of the inner ear. Balance signals go mainly to the nerves that move the eyes. This vestibulo-ocular reflex keeps vision clear. Nearly everyone feels motion sickness at least once in a lifetime.

What does the sea-state code mean for a Zakynthos boat trip?

In the WMO sea state code, code 0 means calm, glassy water with no waves. Code 4, “moderate”, means waves of 1.25 to 2.5 m. Code 5, “rough”, means 2.5 to 4 m. The code also grades swell as low, moderate or high.