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 is being 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 chosen to cover areas where United States (U.S.) Navy activity is substantial, including Chesapeake Bay waters near Naval Station Norfolk, Joint Expeditionary Base (JEB) Little Creek (LC), and JEB Fort Story, as well as a Mine Exercise (MINEX) Area (W-50) in the Atlantic off the coast of Virginia Beach, Virginia. Twenty-five line-transect surveys were completed in two zones (INSHORE and MINEX) between August 2012 and November 2013, with 2,810 kilometers (km) and 8,942 minutes completed on-effort. The majority of sightings were bottlenose dolphins (Tursiops truncatus), although humpback whales (Megaptera novaeangliae) and short-beaked common dolphins (Delphinus delphis) were also sighted in the study area on occasion. In addition, loggerhead sea turtles (Caretta caretta) and leatherback sea turtles (Dermochelys coriacea) were sighted during the study period. Conventional line-transect analysis of bottlenose dolphin sightings showed both spatial and seasonal variation in density and abundance, with greatest abundance in the INSHORE zone during summer months. INSHORE densities were calculated as 3.05 individuals per square kilometer (km2) (N=948) in fall, 0.40 individuals per km2 (N=123) in winter, 1.09 individuals per km2 (N=337) in spring, and 3.52 individuals per km2 (N=1,094) in summer. MINEX densities were calculated as 0.11 individuals per km2 (N=105) in fall, 0.00 individuals per km2 (N=0) in winter, 0.10 individuals per km2 (N=90) in spring, and 0.16 individuals per km2 (N=148) in summer. A photo-ID catalog was created using photos taken during both dedicated photo-ID and line-transect surveys through July 2013; it contains 308 identified individuals to date. Thirty-three individuals were re-sighted; however, most sightings were less than three months and 15 km apart. Additional survey effort will be required before any clear movement patterns can be determined. C-POD acoustic data loggers (www.chelonia.co.uk) were deployed at four sites throughout the study area to cover areas of high U.S. Navy activity. Harbor porpoises (Phocoena phocoena) were detected in low numbers near NSN and JEB-LC during winter and spring deployments, and bottlenose dolphins were detected in each deployment location during all deployments from August 2012 to September 2013. Deployments, however, did not provide consistent coverage due to loss of gear. Further study is required to improve accuracy in seasonal density estimates and allow further stratification of those estimates, and to better describe the movement patterns and site fidelity of the bottlenose dolphins in these waters. Visual surveys and additional C-POD deployments are currently planned through August 2014.

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.

[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.

The dataset has been updated over time as outlined below. Each entry includes the version number, release date, type of change, and a short description.

Overview

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
bearing
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
counttotbest
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
latanimal
latplatform	The latitude of the platform in decimal degrees
legnumber	A unique identifier for the leg associated with the survey
longanimal
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
datetime
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)
spcsnmsci
sp_tsn	ITIS 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
contract
geom	Geometry field added by OBIS-SEAMAP