SWFSC Marine Mammal Survey, Delphinus 2009, Cruise 1640

NOAA Southwest Fisheries Science Center (SWFSC)

The 2009 "Ecosystem Survey of Delphinus Species" research survey focused on the two species of common dolphin, Delphinus delphis and D. capensis, found off southern California, USA, and Baja California, Mexico. The primary objective was to provide information to improve conservation and management plans for these species. The project used a multidisciplinary approach. For both Delphinus species, data were collected to estimate abundance, pregnancy and birth rates, timing of reproduction, gene flow, and
contaminant concentrations. Oceanographic data were collected to characterize habitat, and data on distribution and abundance of seabirds, prey fishes, and squids were collected to further characterize the ecosystem in which these dolphins live. Photographs of dolphin schools were taken from a NOAA Twin Otter aircraft while the survey was being conducted. The aerial photographs will provide count and measurement data to calibrate observer
estimates of school size and to estimate timing of reproduction and birth rates. This research will facilitate understanding population demography of these species in an ecosystem framework. Essential information about the primary focal species, D. capensis, will greatly increase our knowledge about this coastal species and the geographic extent of a Mexico-U.S. transboundary stock. For additional information about the Delphinus cruise, please see http://swfsc.noaa.gov/prd-delphinus.aspx.

The primary objectives of the 2009 Delphinus ecosystem cruise were (1) to characterize the distribution, habitat and reproductive characteristics of long- and short-beaked common dolphins, and (2) to improve non-lethal sampling techniques for studying reproduction in wild, free-ranging cetaceans.

[2021-04-13] Updated with additional attributes.

SWFSC MMTD Cruise Number: 1640
Perpendicular distance will be released upon permission by the contributor. Please contact the contributor if needed.

Attribute descriptions for effort data:
dist: Length of the segment (km)
Mode: Effort mode type (C = closing mode; P = passing mode)

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	Unique ID number (generated by OBIS-SEAMAP)
event	S = marine mammal sighting; t = sea turtle sighting; p = pinniped sighting
datetime	Date and time of sighting (local time)
lat	Latitude (decimal degrees) of vessel when sighting was made
lon	Longitude (decimal degrees) of vessel when sighting was made
cruise	SWFSC Marine Mammal and Turtle Divison Cruise number
sightno	Sighting number (within Cruise)
nsp	Number of species observed in the sighting
mixed	TRUE for a multi-species sighting (nSp >= 2); FALSE otherwise (nSp = 1)
spcode	Species code
sp_tsn	Taxonomic Serial Number added by OBIS-SEAMAP
gsspbest	The mean of all observers
gssphigh	The mean of all observers
gssplow	The mean of all observers
perpdistkm	Perpendicular distance (km) to sighting from trackline; Available upon permission.
bft	Beaufort sea state, as assessed by looking upswell with the naked eye.
swellhght	Average swell height from trough to crest of typical swells (estimated in feet, by eye)
vis	A measure of air/atmospheric clarity
groupsize_sightno	Running count ID of all cetacean groups recorded (should be same as SightNo)
groupsize_count	Number of observers that provided a group size estimate (for calculating GsSpBest) for S events.
groupsize_count_obs	Number of unique observer codes per sighting for S events
geom	Geometry field added by OBIS-SEAMAP