Multi-species marine sighting survey in Golfo Dulce, Costa Rica, Jan-Feb 2010

Brooke Bessesen

During the months of January and February 2010, 30 daily marine fauna sighting surveys were systematically conducted across the waters of Golfo Dulce, a tropical fiord-like embayment in the South Pacific region of Costa Rica. Special focus was placed on cetaceans, chelonids, whale sharks and pelagic sea snakes. Within the 233 logged observation hours, 234 first-hand sightings were recorded from a small panga; photo-identification was collected for 76% of those sightings. Dozens of marine species were documented during the survey period, but those that played most prominently in the survey were Humpback whales (Megaptera novaengiae), bottlenose dolphins (Turciops truncatus), pantropical spotted dolphins (Stenella attenuata), green/black sea turtles (Chelonia mydas agassizii), olive ridley sea turtles (Lepidochelys olivacea), hawksbill sea turtles (Eretmochelys imbricata), and pelagic sea snakes (Pelamis platurus). The study was marked by a lack of sightings for whale sharks (Rhinocodon typus), a species expected inside Golfo Dulce at the time of study.

This pilot project was designed to collect baseline data regarding the marine species that enter or reside in Golfo Dulce during the dry season months of January and February, and to determine spatialdistribution for species seen during the study period.
Sighting coordinates are based on the display of a handheld Garmin handheld GPS III. Measure accuracy is untested. Several other data attributes were also collected during our survey, including: Geographical area, distinctive markings, initial distance from boat, closest approach distance, swim direction, behavior, associated fauna, and environmental conditions (bi-daily).

The best estimate recorded was used as the obs_count; when it was blank, the minimum estimated number of animals was used; when it was blank, too, the sum of the number of adults and young was used.

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.
Only minimum required attributes are visible and downloadable online. Other attributes may be obtained upon provider's permission.

Attributes in dataset

Attribute (table column)	Description
oid	Unique ID number (generated by SEAMAP)
sighting	Sighting number
obs_date	Observed date
obs_time	Observed time
latitude	Latitude of observation
longitude	Longitude of observation
sp_obs	Species observed
sp_tsn	Species ITIS TSN
idrel	ID reliability code
bestest	Best estimated number of animals
minnum	Minimum number of animals
maxnum	Maximum number of animals
adults	Number of adults
young	Number of young
obs_count	Observed count