The Dana expeditions were four Danish research expeditions undertaken by the ''Dana I'' and ''Dana'' ''II''. They were funded in part by the

Carlsberg Foundation Carlsberg Foundation ( da, Carlsbergfondet) was founded by J. C. Jacobsen in 1876, by allocating some of his shares in the Carlsberg Brewery to fund and operate the Carlsberg Laboratory and the Museum of National History at Frederiksborg Palace. ...

and led by Johannes Schmidt. The first three expeditions took place from 1920 to 1922 and the fourth and final was from 1928 to 1930. They centered around investigating the breeding of eels. The first two expeditions allowed Schmidt to prove his theory that European eels migrate to the

Sargasso Sea The Sargasso Sea () is a region of the Atlantic Ocean bounded by four currents forming an ocean gyre. Unlike all other regions called seas, it has no land boundaries. It is distinguished from other parts of the Atlantic Ocean by its charac ...

to spawn. The final expedition traveled to the

Indian Ocean The Indian Ocean is the third-largest of the world's five oceanic divisions, covering or ~19.8% of the water on Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia to the east. To the south it is bounded by th ...

and gathered numerous samples.

First expeditions (1920–1922)

Planning

From 1920 to 1922, ''Dana'' undertook a series of three expeditions that were led by the marine biologist Johannes Schmidt. Schmidt and C. F. Dreschel had first proposed an expedition that would explore the

deep sea The deep sea is broadly defined as the ocean depth where light begins to fade, at an approximate depth of 200 metres (656 feet) or the point of transition from continental shelves to continental slopes. Conditions within the deep sea are a combin ...

of the

Atlantic Ocean The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe ...

in 1916. Although the two men originally envisioned a single large expedition, in January 1917 Schmidt had suggested instead running two expeditions with the first focusing on the Atlantic and the second circumnavigating the world over the course of two years. The two decided to focus first on the Atlantic and began planning and purchasing supplies for it, an endeavor that was complicated by the ongoing

First World War World War I (28 July 1914 11 November 1918), often abbreviated as WWI, was one of the deadliest global conflicts in history. Belligerents included much of Europe, the Russian Empire, the United States, and the Ottoman Empire, with fightin ...

and Schmidt's battle with

bronchitis Bronchitis is inflammation of the bronchi (large and medium-sized airways) in the lungs that causes coughing. Bronchitis usually begins as an infection in the nose, ears, throat, or sinuses. The infection then makes its way down to the bronchi. ...

. By early 1918 they had gathered the bulk of necessary supplies. Schmidt continued to emphasize that he felt an attempted circumnavigation worthwhile, particularly for the attention it could generate at a comparable cost. Such an expedition also held the potential to increase the prestige of Danish marine science dramatically, as the

Challenger expedition The ''Challenger'' expedition of 1872–1876 was a scientific program that made many discoveries to lay the foundation of oceanography. The expedition was named after the naval vessel that undertook the trip, . The expedition, initiated by Wil ...

did for the UK. His efforts to convince Dreschel to refocus the planned expedition, although they continued into 1919, were unsuccessful. In January 1919 it was agreed that the first expedition would leave

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in March for a three month expedition. Upon the end of the First World War in November 1919, the first expedition was almost set to begin, as the ''Dana'' had been completed by H.N. Andersen's

East Asiatic Company The EAC Invest A/S, formerly known as the Santa Fe Group and East Asiatic Company ( da, italic=yes, Det Østasiatiske Kompagni or ''ØK'') is a multinational holding and investment company, based in Copenhagen, Denmark. History The East Asiat ...

. Andersen had agreed to loan Schmidt and Dreschel the vessel for their expedition and fund its operation for a three month period, but launching was delayed until 1920 so that equipment could be purchased at more reasonable prices. In the interim ''Dana'' was used by the company to ship freight. Next, Schmidt and Dreschel decided on an 'executive committee' for the expedition, which they determined would have

Prince Valdemar of Denmark Prince Valdemar of Denmark (27 October 1858 – 14 January 1939) was a member of the Danish royal family. He was the third son and youngest child of Christian IX of Denmark and Louise of Hesse-Kassel. He had a lifelong naval career. Early li ...

as the figurehead, include a representative from the

board of directors and include many other prominent Danes. The expedition was announced to the public in the summer of 1919. After the announcement, Schmidt rushed to execute their plans as he hoped to prove his theory that European eels migrate to the

to spawn before other researchers could beat him to it. As a result, the large expedition was divided into two, the first being one that could be conducted quickly and with minimal set-up. In autumn 1920 Schmidt and Dreschel came into conflict when Dreschel indicated a desire to invite member countries of the

International Council for the Exploration of the Sea The International Council for the Exploration of the Sea (ICES; french: Conseil International de l'Exploration de la Mer, ''CIEM'') is a regional fishery advisory body and the world's oldest intergovernmental science organization. ICES is headqu ...

to join the second expedition. Schmidt sought to keep the effort limited to Denmark and threatened to abandon the effort if it wasn't. Nothing came of the plans.

First and second

The expedition began in early 1920 in England, and ''Dana'' left the nation in 17 March for Gibraltar. Schmidt joined the boat in

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and it had arrived in the

Canary Islands The Canary Islands (; es, Canarias, ), also known informally as the Canaries, are a Spanish autonomous community and archipelago in the Atlantic Ocean, in Macaronesia. At their closest point to the African mainland, they are west of Morocc ...

by April. They left there on 11 April and arrived in the Sargasso Sea within seven days. Shortly thereafter, the crew began fishing large amounts of European eel larvae, searching for their breeding grounds. Before they could, the ship began to leak and was forced to travel to Charlotte Amalie, St. Thomas, for repairs. As a result of the failure, the East Asiatic Company agreed to give Schmidt another three months with the ship. They waited on St. Thomas for a month and returned to the Sargasso Sea in June. By then, however, the ship had missed the season where eel eggs were hatching. They caught 6,069 larvae of European eels, and 1,027 of

American eel The American eel (''Anguilla rostrata'') is a facultative catadromous fish found on the eastern coast of North America. Freshwater eels are fish belonging to the elopomorph superorder, a group of phylogenetically ancient teleosts. The America ...

before the first expedition ended on July 4 in the

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. ''Dana'' was shortly returned to the East Asiatic Company in

Charleston, South Carolina Charleston is the largest city in the U.S. state of South Carolina, the county seat of Charleston County, and the principal city in the Charleston–North Charleston metropolitan area. The city lies just south of the geographical midpoint o ...

, and the group returned to Denmark. They still retained a majority of funds that had been raised but had not gotten definitive evidence to support the claim that European eels spawned in the Sargasso Sea. A second expedition left on August 30 1921, with a similar aim.

Third

Schmidt's third expedition earned him a reputation "as a first rate marine scientist." In autumn 1920 the Danish government purchased a new research ship for marine research in Great Britain. It was transported to Denmark, overhauled, and renamed R/V ''Dana'' or ''Dana II''. The boat had of metal wire, allowing it to "fish deeper than anyone before." The expedition began in late 1921, arriving near Portugal and Spain in September, where they investigated the strait of Gibraltar. Over the course of ten months, the expedition did work. In early December, the Carlsberg Foundation agreed to fund an extension of the expedition to travel through the

Panama Canal The Panama Canal ( es, Canal de Panamá, link=no) is an artificial waterway in Panama that connects the Atlantic Ocean with the Pacific Ocean and divides North and South America. The canal cuts across the Isthmus of Panama and is a conduit ...

, which it did on 10 January. In the Pacific, ''Dana II'' took numerous samples that revealed the Pacific Ocean was cooler and less salty than the Atlantic. They also found an

oxygen minimum zone The oxygen minimum zone (OMZ), sometimes referred to as the shadow zone, is the zone in which oxygen saturation in seawater in the ocean is at its lowest. This zone occurs at depths of about , depending on local circumstances. OMZs are found worl ...

around below the surface, making those aboard ''Dana II'' the first researchers to document such a phenomenon. High plankton densities helped the expedition observe

upwelling Upwelling is an oceanographic phenomenon that involves wind-driven motion of dense, cooler, and usually nutrient-rich water from deep water towards the ocean surface. It replaces the warmer and usually nutrient-depleted surface water. The nutr ...

and deep-level samples gave them an image of species richness greater than that in the Atlantic. On 20 January, they left the Pacific and, after stopping in

Lake Gatun Gatun Lake ( es, Lago Gatún) is a large freshwater artificial lake to the south of Colón, Panama. At approximately above sea level, it forms a major part of the Panama Canal, carrying ships of their transit across the Isthmus of Panama. Gatun ...

where they found large amounts of

desmid Desmidiales, commonly called desmids (''Gr.'' ''desmos'', bond or chain), are an order in the Charophyta, a division of green algae in which the land plants (Embryophyta) emerged. Or in other words, Desmid, (order Desmidiales), order of single- ...

algae, they returned to Europe from Bermuda on 30 May.

Aftermath

From 1922 to 1923 Schmidt published his theory about the breeding of the eels, and his expedition found growing fame in magazines, pottery, and various awards. The expedition had discovered numerous new species, captured valuable live specimens, and made several important discoveries. A reenactment was filmed in October 1922. Dana II leaving Copenhagen

Fourth expedition (1928–1930)

Schmidt embarked on his fourth ''Dana'' expedition in June 1928 and returned in June 1930. Its official title was "The Carlsberg Foundation's Oceanographical Expedition round the World 1928-30 under the Leadership of Professor Johannes Schmidt" and was Schmidt's largest expedition. The ship traveled over from Europe to the

Indo-Pacific The Indo-Pacific is a vast biogeographic region of Earth. In a narrow sense, sometimes known as the Indo-West Pacific or Indo-Pacific Asia, it comprises the tropical waters of the Indian Ocean, the western and central Pacific Ocean, and the ...

. It was aimed in part at investigating the oxygen minimum zone that had been discovered in 1920 and also at investigating freshwater eels in the

. They found larva of a "true"

freshwater eel The Anguillidae are a family of ray-finned fish that contains the freshwater eels. Eighteen of the 19 extant species and six subspecies in this family are in the genus ''Anguilla''. They are elongated fish with snake-like bodies, their long dorsa ...

in the Pacific and numerous other samples. Schmidt also used the expedition to confirm his earlier research. ''Nature'' wrote that "From North Iceland and the

Davis Straits Davis Strait is a northern arm of the Atlantic Ocean that lies north of the Labrador Sea. It lies between mid-western Greenland and Baffin Island in Nunavut, Canada. To the north is Baffin Bay. The strait was named for the English explorer Joh ...

southwards to Brazil, and from the

Baltic Baltic may refer to: Peoples and languages * Baltic languages, a subfamily of Indo-European languages, including Lithuanian, Latvian and extinct Old Prussian *Balts (or Baltic peoples), ethnic groups speaking the Baltic languages and/or originati ...

and

Black Sea The Black Sea is a marginal mediterranean sea of the Atlantic Ocean lying between Europe and Asia, east of the Balkans, south of the East European Plain, west of the Caucasus, and north of Anatolia. It is bounded by Bulgaria, Georgia, Roma ...

in the east to the United States and Panama in the west, Prof. Schmidt and his collaborators have studied methodically the physical, chemical, and biological conditions of the waters from surface to bottom." The expedition also found a giant larva that they believed belonged to the

eel Eels are ray-finned fish belonging to the order Anguilliformes (), which consists of eight suborders, 19 families, 111 genera, and about 800 species. Eels undergo considerable development from the early larval stage to the eventual adult stage ...

genus. Based on the size and growth rate of the common eel, they estimated this larva would grow to be long. Eleven years later

Anton Frederik Bruun Anton Frederik Bruun (14 December 1901 – 13 December 1961) was a Danish oceanographer and ichthyologist. Educated at University of Copenhagen (1926) and employed at the Danish Commission for Marine Research (Kommissionen for Danmarks Fiskeri- ...

, who had helped lead the expedition, said "I believe in the

sea serpent A sea serpent or sea dragon is a type of dragon sea monster described in various mythologies, most notably Mesopotamian (Tiamat), Judaeo-Christian (Leviathan), Greek (Cetus, Echidna, Hydra, Scylla), and Norse (Jörmungandr). Mythology and folk ...

First expeditions (1920–1922)

Planning

First and second

Third

Aftermath

Fourth expedition (1928–1930)

Notes

References

Bibliography

Further reading