Norfolk/VA Beach MINEX Vessel Surveys

The U.S. Navy Marine Species Monitoring Program

A combination of visual line-transect survey, photo-identification (photo-ID), and automated acoustic monitoring methods was used to gather important baseline information on the occurrence, distribution, and density of marine mammals near Naval Station Norfolk (NSN) and adjacent areas. The study area was designed to cover areas where United States Navy activity is substantial, including Chesapeake Bay waters near NSN and Joint Expeditionary Base Little Creek-Fort Story, as well as a Mine Exercise (MINEX) Area (W-50) in the Atlantic Ocean off the coast of Virginia Beach, Virginia. Sixty-one line-transect surveys were completed in two zones (INSHORE and MINEX) between August 2012 and August 2015, with 6,550 kilometers (km) and 349.6 hours completed on-effort. The majority of sightings were of bottlenose dolphins (Tursiops truncatus), although humpback whales (Megaptera novaeangliae), harbor porpoises (Phocoena phocoena), and short-beaked common dolphins (Delphinus delphis) were also sighted in the study area on occasion. In addition, loggerhead sea turtles (Caretta caretta), leatherback sea turtles (Dermochelys coriacea), and a Kemp’s ridley sea turtle (Lepidochelys kempii) were sighted during surveys. Conventional line-transect analysis of bottlenose dolphin sightings showed both spatial and seasonal variation in density and abundance, with greatest density in the INSHORE zone during fall months. Densities in the INSHORE zone were calculated as 3.88 individuals per square kilometer (km2) (abundance[N]=1,203) in fall, 0.63 individuals per km2 (N=195) in winter, 1.00 individuals per km2 (N=311) in spring, and 3.55 individuals per km2 (N=1,101) in summer. Densities in the MINEX zone were calculated as 2.14 individuals per km2 (N=1,277) in fall, 0.06 individuals per km2 (N=37) in winter, 1.53 individuals per km2 (N=913) in spring, and 1.39 individuals per km2 (N=829) in summer. Twenty-seven photo-ID surveys were completed, and a photo-ID catalog was created using photos taken during both dedicated photo-ID and line-transect surveys through May 2014; it contains 878 identified individuals to date. Subsequent photos will continue to be added and analyzed. One hundred ten individuals were re-sighted; however, most re-sightings were less than 4 months and 30 km apart. Additional survey effort and further analysis will be required before any clear movement patterns can be determined. C-POD acoustic data-loggers were initially deployed at four sites throughout the study area to cover areas of high United States Navy activity. Bottlenose dolphins were detected in each deployment location during all deployments from August 2012 to December 2015. Though deployments did not provide consistent coverage in all seasons for all sites due to loss of gear, results from two deployment sites nearest to NSN showed a greater level of occurrence during fall months, and a diel pattern of occurrence with increased detections during nighttime hours for three deployment sites.

The HDR Marine Species Monitoring (MSM) Team was tasked to initiate a monitoring project in coastal waters around NSN, JEB-LC, JEB-FS, and the Virginia Beach waterfront, including the VACAPES MINEX W-50 training area. The main objective is to provide quantitative data and information on the seasonal occurrence, distribution, and density of marine mammals. Effort was dedicated to working with local researchers and employing proven marine mammal monitoring and research techniques to accomplish the following:

1. Conduct monthly systematic line-transect surveys to determine distribution of marine mammals in the vicinity of NSN, JEB-LC, JEB-FS, and the MINEX W-50 area.

2. Conduct monthly photo-identification (photo-ID) surveys during summer months to determine the site fidelity and distributional patterns of marine mammals utilizing the areas listed above.

3. Supplement visual surveys by deploying and retrieving four C-POD acoustic recording devices to monitor for dolphin echolocation clicks in specific locations.

[2019-08-27] New data were appended and some columns with empty values were removed. The dataset name is changed by dropping the time period part.

[2014-11-25] Attributes were reorganized so that they meet provider's data schema and effort data (tracklines) were added.

The project is on-going and more data will be added
periodically.
The sighting coordinates represent the locations of the animals (not the vessel platform) calculated from reticle and bearing.

This dataset includes a subset of the data collection for the Norfolk-VABeach Vessel surveys.
Other data of the collection are available in the following datasets:
Norfolk/VA Beach Inshore Vessel Surveys Nov 2012- Nov 2013
Norfolk/VA Beach Photo-ID Surveys Aug 2012-Sep 2013

All the US Navy-funded survey datasets are found in the OBIS-SEAMAP US Navy page.

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	oid for internal use
bearingabs	True (not magnetic) bearing to sighting. Calculated from relative bearing and platform bearing. degrees
beaufortscale	Beaufort sea state (0-12)
behavior	Initial behavioral state of the animal or group when first observed. Examples: Travel, Mill, Rest
countcalves	The number of calves in the sighting
counttotmax	The highest estimate of the number of animals in the sighting
counttotmin	The lowest estimate of the number of animals in the sighting
cue	The sighting cue that initially drew the observers attention
depthsounding	Depth as determined in situ via sounding in meters
distsight	The radial distance to the animal
distsightperp	The perpendicular distance to the animal from the trackline
effortstatus	The effort status of the platform. Options: On-effort (systematic), on-effort (focal follow), on-effort (circling), on-effort (random), off-effort (connector lines), off-effort (transiting), off-effort (other)
glareleft	The amount of glare (0-100%) on the left (port) side of the platform. Refers to glare from 0 to 90 degrees, or viewshed for which observer is reponsible (percent).
glareright	The amount of glare (0-100%) on the right (starboard) side of the platform. Refers to glare from 270-360 degrees, or viewshed for which observer is reponsible (percent).
headingplatmagnetic	Heading of the observation platform relative to magnetic North in degrees
headingplattrue	Heading of the observation platform relative to true North in degrees
latplatform	The latitude of the platform in decimal degrees
legnumber	A unique identifier for the leg associated with the survey
longplatform	The Longitude of the platform in decimal degrees
observer	The name of the observer who first sighted the animal
observerleft	Name of the observer on the left (port) side of the platform
observerright	Name of the observer on the right (starboard) side of the platform
ocean	The ocean where the survey took place (Pacific, Atlantic, Indian, etc.)
percentcloudcover	Cloud cover as represented by a percentage (percent)
photoframes	The photo frames used for the sighting; or total frames taken
photogapher	Name of the photographer
photos	Were photos taken as part of the sighting? (Y/N)
pic	Pilot in command
platformded	Indicates if the survey was a dedicated marine mammal survey, or if data was gathered opportunistically from a platform on a different mission (Y/N)
platformspeed	Speed of the platform at the time of the sighting in knots
platformtype	Type of survey platform (e.g., "aerial", "vessel")
rangecomplex	The Range complex (or complexes) associated with the survey (JAX, SOCAL, Cherry Point, etc.)
reactioninit	The type of reaction at the initial time of the sighting relative to the observation platform
recorder	Name of the person recording data
datetimeutc	Date and Time together in one cell value (UTC)
sightingnotes	Notes field to capture information not covered by existing attributes or other information of interest
sightingnumber	The sighting number for the particular survey day
spcsnmcom	Common name of the sighted species. Output should be singular (e.g. bottlenose dolphin)
sp_tsn	Taxonomic Serial Number added by OBIS-SEAMAP
surveyid	A survey identifier consisting of data collector, range complex, platform, year, month, and day. (Data Collector/Source)_(Range Complex)_(Platform Type or Details)_(Year)(Month)(Day) (eg. SES_SOCAL_Aerial_20120417)
surveypoint	A waypoint taken along a trackline OR a start/end point for a trackline
swell	Swell height in ft
vertangleorreticle	Reticle or declination angle in degrees
visibility	The estimated distance at which an animal could potentially be sighted in km
geom	Geometry field added by OBIS-SEAMAP