Rescuing biogeographic legacy data: The "Thor" Expedition, a historical oceanographic expedition to the Mediterranean Sea.
BACKGROUND
This article describes the digitization of a series of historical datasets based οn the reports of the 1908-1910 Danish Oceanographical Expeditions to the Mediterranean and adjacent seas. All station and sampling metadata as well as biodiversity data regarding calcareous rhodophytes, pelagic polychaetes, and fish (families Engraulidae and Clupeidae) obtained during these expeditions were digitized within the activities of the LifeWatchGreece Research Ιnfrastructure project and presented in the present paper. The aim was to safeguard public data availability by using an open access infrastructure, and to prevent potential loss of valuable historical data on the Mediterranean marine biodiversity.


CONCLUSIONS
The datasets digitized here cover 2,043 samples taken at 567 stations during a time period from 1904 to 1930 in the Mediterranean and adjacent seas. The samples resulted in 1,588 occurrence records of pelagic polychaetes, fish (Clupeiformes) and calcareous algae (Rhodophyta). In addition, basic environmental data (e.g. sea surface temperature, salinity) as well as meterological conditions are included for most sampling events. In addition to the description of the digitized datasets, a detailed description of the problems encountered during the digitization of this historical dataset and a discussion on the value of such data are provided.
Institute of Marine Biology, Biotechnology and Aquaculture, Hellenic Centre for Marine Research, Heraklion, Crete, Greece.
Dimitra
D
Mavraki
Institute of Marine Biology, Biotechnology and Aquaculture, Hellenic Centre for Marine Research, Heraklion, Crete, Greece; Australian Museum Research Institute, Sydney, NSW, Australia.
Lucia
L
Fanini
Institute of Oceanography, Hellenic Centre for Marine Research, Anavyssos, Athens, Greece.
Marilena
M
Tsompanou
Institute of Marine Biology, Biotechnology and Aquaculture, Hellenic Centre for Marine Research, Heraklion, Crete, Greece.
Vasilis
V
Gerovasileiou
Institute of Marine Biology, Biotechnology and Aquaculture, Hellenic Centre for Marine Research, Heraklion, Crete, Greece.
Stamatina
S
Nikolopoulou
Institute of Marine Biology, Biotechnology and Aquaculture, Hellenic Centre for Marine Research, Heraklion, Crete, Greece.
Eva
E
Chatzinikolaou
Institute of Marine Biology, Biotechnology and Aquaculture, Hellenic Centre for Marine Research, Heraklion, Crete, Greece.
Wanda
W
Plaitis
University of Patras, Department of Biology, Laboratory of Zoology, Rio, Patras, Greece; Institute of Marine Biology, Biotechnology and Aquaculture, Hellenic Centre for Marine Research, Heraklion, Crete, Greece.
Sarah
S
Faulwetter
 Clupeiformes ;  Digitization ;  Polychaeta ;  Rhodophyta ; Danish Oceanographical Expedition; Data archaeology; Data management; Data rescue; Historical dataset; Marine biodiversity