Mediterranean seabird surveys 99/00/02

Institut de Ciències del Mar, CMIMA (CSIC), Barcelona, Spain

Replicate springtime (May - June) vessel-based surveys in the western Mediterranean during standardized trawl surveys of the Spanish continental shelf and slope over three years (1999, 2000, 2002), provide broad-scale information on seabird distributions from the Strait of Gibraltar to Cape Creus.


All observations were made by the same observer (Jose Maria Arcos) during 1999, 2000, and 2002 using standardized strip-transect techniques (Tasker et al. 1984) with specific adaptations to the study area. A 300 m strip-width transect band was used, counting at both sides of the vessel (i.e., surveying a 600 m band) when the conditions (light and wind) were appropriate. Snap-shot counts for flying birds were used. All birds observed during the surveys were recorded and aggregated into 10-minute bins.

To study the distribution and oceanographic habitat of seabirds in the Western Mediterranean during the spring (May - June) of multiple years. Surveys were conducted onboard B/O Cornide de Saavedra research vessel, as part of the annual MEDITS trawl surveys, extending along the Mediterranean coast of the Iberian Peninsula, from the Strait of Gibraltar in the southwest to Cape Creus in the northeast.


Maite Louzao processed the at-sea data, as part of her Ph.D. dissertation, in the laboratory of Dr. Daniel Oro, at the Mediterranean Institute for Advanced Studies (IMEDEA), in Mallorca, Spain.

[2020-10-01] The following invalid species names were corrected according to the Integrated Taxonomic Information System (ITIS).
Larus audouinii (176842) => Ichthyaetus audouinii (824066)
Little Tern: Sterna albifrons (176899) => Sternula albifrons (824126)
Mediterranean Gull: Larus melanocephalus (176858) => Ichthyaetus melanocephalus (824070)
Sandwich Tern: Sterna sandvicensis (176927) => Thalasseus sandvicensis (176932)

The original dataset includes 17 species names (columns) whose values represented animal counts for each 10-minute survey bin. In the OBIS-SEAMAP dataset, these columns are transposed to rows, each of which is a record for a single species.

Due to recent changes in the taxonomy of Mediterranean seabirds, the species Puffinus yelkouan can include either Puffinus yelkouan or Puffinus mauretanicus because the latter has not been assigned an ITIS number. Even though both species are identified by the same code, they can be told apart using the field 'sp_obs.' Puffinus mauretanicus is coded as 'PM' and Puffinus yelkouan as 'PY.'

The original dataset also includes ancillary data on the survey effort (length, survey strip width, area surveyed for each 10-minute bin, and vessel speed) and environmental conditions during surveys (Beaufort sea state, presence/absence of rain, and the proportion of cloud cover in the sky).

Reference: Tasker, M.L., P.H. Jones, T. Dixon, and B.F. Blake. 1984. Counting seabirds at sea from ships: A review of methods employed and a suggestion for a standardized approach. Auk 101:567-577.

Overview

Attributes described below represent those in the original dataset provided by the provider.
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Attributes in dataset

Attribute (table column)	Description
dataset
lineno
date	Observed date
year	Year of observation
month	Month of observation
day	Day of observation
time	Time of observation
hour	Hour of observation
minute	Minute of observation
lat	Latitude of observation
lon	Longitude of observation
beaufort
clouds
rain
ship_speed
strip_m
distance
area
species	Species observed
scientific
tsn	Species ITIS TSN
obs_count	Number of animals observed
excluded
oid	Unique ID number (generated by SEAMAP)