MMS Low Altitude Survey 1980-1983
Minerals Management Service

Dataset credit

Minerals Management Service

Contacts

RoleNameOrganization 
Primary contact Glenn Ford
Primary contact Janet Casey N/A
Primary contact Thomas P. Dohl University of California, Santa Cruz N/A
Data entry Benjamin Best Duke University

Citation

Abstract

This dataset is from the marine mammal and seabird surveys of central and northern California studies: Central/northern California - low aerial [birds and mammals] study code: CL, Contract number: 14-12-0001-29090, Principal investigator: Thomas P. Dohl, Center for Marine Studies, University of California, Santa Cruz

Time period: February 1980 through June 1983
Study area: Shelf, slope, and offshore waters to a distance of 100 nm off the California coast from Point Conception to the California-Oregon boundary.

Methodology: Offshore transect surveys were flown twice-monthly at two different altitudes (200 ft and about 750-1,000 ft ASL) along approximately 40 east-west transect lines extending an average of 60 nm offshore. The transects sampled on a given survey were selected randomly from a set of 92 standard (predetermined) lines spaced at intervals of 5’ of latitude. Standard transects provided systematic coverage of shelf, slope, and offshore waters in the study area. Sightings of seabirds, pinnipeds, and sea otters were recorded only on low-altitude surveys. Sightings of cetaceans and turtles were recorded on both low- and high-altitude surveys. Seabird sightings were recorded only on the shaded side of the aircraft within a strip transect of 50 m width. Marine mammal and turtle sightings were recorded within an unbounded corridor on both high- and low-altitude surveys, but only the shaded side of the aircraft was searched on the low-altitude surveys. Cross-legs connecting standard transects were searched only on high-altitude surveys. Offshore cross-legs were searched on both sides of the aircraft, while only the nearshore side was searched on cross-legs along the coast. Declination angle was measured and noted for each marine mammal/turtle sightings and later used to calculate a probability density function of frequency with right-angle sighting distance. Navigation was by Loran and VLF-Omega.

Databases produced: Three databases of sightings at sea were produced by these studies (data on numbers of seabirds and pinnipeds on land were also collected but are not addressed in the present study). These include: 1) sightings of cetaceans and turtles recorded on 36 high-altitude aerial surveys, 2) sightings of cetaceans, pinnipeds, sea otters, and turtles recorded on 36 low-altitude aerial surveys, and 3) sightings of seabirds on 36 low-altitude aerial surveys. Each sighting database is accompanied by files providing the search effort on transect and environmental characteristics of the waters surveyed (e.g., sea surface temperature).

Purpose

To determine species composition, distribution, abundance, and seasonal variation for marine mammal and seabird populations, provide a description of habitat use, and identify areas of special biological importance to these populations in the central and northern California study area.

Supplemental information

N/A

References

Bonnell, M.L., M.O. Pierson and G.D. Farrens. 1983. Pinnipeds and sea otters of central and northern California, 1980-1983: Status, abundance, and distribution. Part of Investigator’s Final Report, Marine Mammal and Seabird Study, Central and Northern California, Contract No. 14-12-0001-29090. Prepared by Center for Marine Sciences, University of California, Santa Cruz, for the Pacific OCS Region, Minerals Management Service. OCS Study MMS 84-0044. 220 pp.
Briggs, K.T., W.B. Tyler, D.B. Lewis and K.F. Dettman. 1983. Seabirds of central and northern California, 1980-1983: Status, abundance, and distribution. Part of Investigator’s Final Report, Marine Mammal and Seabird Study, Central and Northern California, Contract No. 14-12-0001-29090. Prepared by Center for Marine Sciences, University of California, Santa Cruz, for the Pacific OCS Region, Minerals Management Service. OCS Study MMS 84-0043. 246 pp.
Dohl, T.P., R.C. Guess, M.L. Duman and R.C. Helm. 1983. Cetaceans of central and northern California, 1980-1983: Status, abundance, and distribution. Part of Investigator’s Final Report, Marine Mammal and Seabird Study, Central and Northern California, Contract No. 14-12-0001-29090. Prepared by Center for Marine Sciences, University of California, Santa Cruz, for the Pacific OCS Region, Minerals Management Service. OCS Study MMS 84-0045. 284 pp.

Attributes

Overview

Attributes described below represent those in the original dataset provided by the provider.
Only minimum required attributes are visible and downlodable online. Other attributes may be obtained upon provider's permission unless otherwise noted below.

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 in dataset provided

Attribute (table column)Description
idID
studyStudy code
platformPlatform code
on_On (Y) or off (N) effort
effdateeffort date
date_0Date in original format
dateDate of the observation
time_0Time in original format
timeTime of the observation
speciesSpecies name
species_codeSpecies code
numberGroup size
latLatitude in decimal degrees
lonLongitude in decimal degrees
widthWidth of the transect
newbornsNumber of calves
malesNumber of males
femalesNumber of females
ageAge
sexSex
plumagePlumage
assocAssociation
directionDirection
group_Group size
behaviorBehavior code
altitudeAltitude in feet
declineDecline
distanceDistance
perpdistdefinition not provided
reldirdefinition not provided
distcodedefinition not provided
commentComments
weatherWeather code
cloudsCloud code
windWind
seastatusSea status
glaredirGlare direction
glareGlare
seatempSea temperature (-99: not available)
recordRecord No.
geomGeometry field added by OBIS-SEAMAP
oidUnique ID number (generated by OBIS-SEAMAP)
OBIS-SEAMAP ID41
Seabirds52,471
Marine mammals4,055
Sea turtles17
Rays and sharks0
Other species14,910
Non spatial0
Non species6
Total71,459
Date, Begin1980-02-25
Date, End1983-01-29
Temporal prec.111111
Latitude34.03 - 42.07
Longitude-126.48 - -119.43
Coord. prec.4 decimal digits
PlatformPlane
Data typeAnimal sighting
EffortN/A
Registered2006-03-21
Updated2013-11-25
StatusPublished
Sharing policy CC-BY-NC (Minimum)
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