NEFSC Marine Mammal Abundance Cruise 2004 Passive Acoustic Monitoring - Rainbow Click Detections

Sofie Van Parijs

The primary objectives of the survey were to:
(1) determine the spatial distribution and abundance of cetaceans and turtles in the study region,
(2) determine the spatial distribution and relative abundance of sea birds in the same region, and
(3) use passive acoustics to record vocalizing cetaceans that will hopefully be used to improve the abundance estimates derived from the visual surveys.
A secondary objective was to compare the distribution of these species with each other, physical characteristics, such as depth contours and water temperature, and biological characteristics, such as relative plankton distributions.

A total of 241 sperm whales were detected during Leg 1 and 220 during Leg 2. Note that sperm whale encounters may not be independent and these numbers are likely to over estimates.

Rainbow Click (medium frequency click detector) detected clicks 53,804 attributed to sperm whales and 2428 clicks to dolphin. Clicks were grouped into events attributed to individual sperm whales and dolphin groups. Where it was not possible to attribute clicks to individual animals estimates of group size associated with an event are given as low, best and high. Note that these events do not reflect the total number of vocalizing cetaceans, nor do they reflect the total number of encounters with cetaceans.

Rainbow Click is a software based click detector developed by Douglas Gillespie for the International Fund for Animal Welfare. It was originally developed to detect the broadband clicks of sperm whales and some dolphin species; although recent hardware developments now allow it to detect narrow band ultrasonic clicks made by Phocena spp. or Kogia spp. The latest implementation of Rainbow Click is in the PAMGUARD software. Currently (2009), Automated species classifiers exist for sperm whales and Phocena spp. New click classifiers are now under development for beaked whales, north Atlantic dolphin species and Kogia spp. at the Sea Mammal Research Unit, University of St. Andrews. Time Of Arrival Differences (TODA) are used to calculate bearings to detected clicks, and clicks are grouped into click trains by an experienced operator. Click trains typically represent one animal. Crossed bearings are used to determine the location of the vocalizing animals.

Additional attributes caveat: The ranges and bearings associated with these data have not been validated or corrected in any way so they may vary from fairly accurate to completely wrong.

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	Observation ID number
obs_date	Date of observation
obs_time	Time of observation start (UTC)
latitude	Latitude of ship
longitude	Longitude of ship
sp_obs	Data provider
sp_tsn	ITIS number for species
obs_count	Number of animals detected
nclicks
duration
perpendiculardistance
id
origeventid
colour
startdate
startdatenum
enddatenum
firstfile
lastfile
comment
firstrange
firstbearing
timeabeam
shiplat
shiplon
whalelat
whalelon
leg