Trawl-survey data from the “expedition Hvar” in the Adriatic Sea (Mediterranean) collected in 1948-1949

OBIS and EurOBIS

The “expedition HVAR” (1948-1949), organised by the Institute of Oceanography and Fisheries of Split (IOF, Croatia), was the first large-scale fishery-independent trawl-survey ever performed in the Adriatic Sea. The survey was conducted with the motorboat “Hvar” (250 HP; LOA = 25 m) in the territorial waters of the former Yugoslavia (currently territorial waters of the Republics of Slovenia, Croatia, Bosnia and Herzegovina and Montenegro) and Albania, and in the international waters to approximately 20 nautical miles off the Italian coast.
The database includes CPUE (n/h and kg/h) indexes of 95 demersal species for 271 hauls at 151 fixed stations. Species synonymies were updated according to the World Register of Marine Species (WoRMS). Some species are grouped into multispecies categories that group taxonomically similar species, i.e. species of the same genus or family (e.g. Raja spp., Triglidae). Information on the sediment type was also reported for each station. The depth of each station was extracted from the EMODnet Digital Bathymetry. Fish samples were taken with a cotton bottom otter-trawl net with wing mesh size of 55 mm, cod-end mesh size of 26 mm, foot-rope of 44 m and head-rope of 35 m. Trawling was carried out during daylight. The average tow speed was 3 knots. The purpose of the research was to determine the qualitative and quantitative characteristics of the demersal communities of fish, crustaceans and cephalopods and to assess the possibility of their exploitation. This survey was conducted in the period when the demersal fish and invertebrate communities were not intensely exploited (“post-war conditions”), and thus this data Jucan serve as a reference baseline for the following changes.

N/A

This dataset was downloaded from OBIS (https://obis.org/). The records for only marine mammals, seabirds, sea turtles and rays and sharks were extracted. Records with no longitude/latitude or no date (eventDate) were excluded.
OBIS dataset page:
https://obis.org/dataset/143e83d6-a818-4ac4-9909-146009f0fd0d
Data Provider's dataset page:
http://ipt.vliz.be/eurobis/resource?r=hvar_trawl_survey_1948_1949

Overview

This section explains attributes included in the original dataset. OBIS-SEAMAP restricts the attributes available to the public to date/time, lat/lon and species names/counts only. Should you need other attributes described here, you are encouraged to contact the data provider.

Attributes described below represent those in the original dataset provided by the provider.
All attributes are included in the downloadable file (CSV or ESRI File Geodatabase) for "Complete Set of Dataset".

Attributes in dataset

Attribute (table column)	Description
oid	Internal ID
id	Record ID
dataset_id	Dataset ID
scientificname	Scientific name
vernacularname	Vernacular name
aphiaid	Aphia ID
taxonrank	taxononic rank
individualcount	Group size / individual count
eventdate	Event date (precision varies)
eventtime	Event time
decimallatitude	Latitude in decimal degrees
decimallongitude	Longitude in decimal degrees
coordinateprecision	Coordinate precision
catalognumber	Catalog number
collectioncode	Collection code
occurrencestatus	Occurrence status
basisofrecord	Basis of record (HumanObservation / MachineObservation)
modified	Date/time the record was modified
node_id	Node ID
occurrenceid	Occurrence ID
occurrenceremarks	Occurrence remarks
eventid	Event ID
institutioncode	Institution code
lifestage	Life stage
sex	Gender of the animal if known
species	Species by provider
datasetid	Dataset ID by provider
country	Country
locality	Location of ocean
waterbody	Details of ocean
dropped	Flag indicating the record was dropped (always false)
absence	Flag indicating the record represents the absence of the species (always false)
marine	Flag indicating the record is for marine life (always true)