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MMS Ship Transect Survey for Mammals and Seabirds, Southern California Bight

Entry ID: seamap52

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Summary

Abstract: Marine Mammal and Seabird Surveys of The Southern California Bight Studies: -- So. Calif. Bight Ship Surveys [Birds and Mammals] Study Code: SS Contract Number: AA550-CT7-36
Principal Investigator(s)/Affiliation: K. S. Norris and B. J. Le Boeuf, University of California, Santa Cruz, and G. L. Hunt, University of California, Irvine.

Purpose: OBJECTIVES: Objectives of the study were to characterize the marine mammal and seabird fauna of the Southern California Bight, estimate abundance of species, describe the distribution, determine the timing and routes of migrations and movements, and document seasonal changes in numbers or patterns of habitat-use. In addition, studies were conducted to determine the size and status of breeding ... colonies of seabirds and pinnipeds, their productivity, and trends in growth.

SUPPLEMENTAL INFORMATION:

DATA COLLECTION:
TIME PERIOD: May 1975 through March 1978
STUDY AREA: The Southern California Bight, from Point Conception to the U.S.-Mexico boundary and offshore to the 2,000 m isobath.

METHODOLOGY: Aerial and ship surveys were conducted along pre-established transects designed to systematically sample marine mammal and seabird abundance in all waters of the study area. Aerial surveys were conducted at two altitudes (200 ft and about 750-1,000 ft ASL) alternating at 2-3 week intervals. Seabirds and pinnipeds were recorded only on the low-altitude surveys which predominantly sampled along eight lines of latitude, separated by 25 nm, and connecting lines of longitude. High-altitude surveys sampled cetacean abundance along 15 Loran lines oriented northeast-southwest and separated by 12-15 nm. On low-altitude surveys, seabirds were counted only within a 50 m corridor on the shaded side of the aircraft. Marine mammals were counted in an unbounded corridor on one side of the aircraft on low-altitude surveys and both sides of the aircraft on high-altitude surveys. A clinometer or marks on the wing-strut were used to estimate the declination, and the measurement or estimate later used to calculate probability density functions of frequency with right-angle distance. Ships were used for surveys of inshore waters along standard (i.e., predetermined and replicate) transects and for search, catch, and tagging/tracking of small cetaceans. The standard ship transect cruises sampled abundance of seabirds and marine mammals over banks, basins, and ridges in waters inshore of the Patton Escarpment (the shelf break). Seabirds and marine mammals were counted on both sides of the cruise track and distance estimated or measured with a range-finder. Catch cruises attempted to find and remain with schools of common dolphin and other small cetaceans; therefore, data on sightings from these cruises cannot be used as samples of animal abundance. The Southern California Bight Study also included ground and aerial censuses of pinniped and seabird colonies, and special studies of productivity, mortality rates, and foraging range.

DATABASES PRODUCED: Databases produced include 1) sightings of seabirds and marine mammals on 24 *low-altitude aerial surveys, 2) sightings of cetaceans on 35 high-altitude aerial surveys, 3) sightings of seabirds and marine mammals on 29 ship transect surveys, and 4) sightings of cetaceans on 34 catch cruises. Included in this database are the following: High Altitude Mammal Observations: 75,489 km of effort, 695 sightings of 68,557 individual animals Low Altitude Mammal Observations: 37,843 km of effort, 1,320 sightings of 15,070 individual animals Low Altitude Bird Observations: 35,445 km of effort, 7,950 sightings of 63,359 individual animals Ship Observations: 17,903 km of effort, 23,519 sightings of 181,287 individual animals

CURRENTNESS REFERENCE: ground condition

SPATIAL REFERENCE INFORMATION - GEODETIC MODEL
Horizontal Datum Name: D_WGS_1984
Ellipsoid Name: WGS_1984
Semi-major Axis: 6378137.000000
Denominator of Flattening Ratio: 298.257224

Related URL

Link: GET DATA

Description: Access data from the OBIS and OBIS-SEAMAP websites.

Multimedia Sample

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Caption: Ship Transect Survey for Mammals and Seabirds

Geographic Coverage

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Spatial coordinates

N: 34.57

S: 31.6

E: -117.18

W: -122.08

Data Set Citation

Dataset Originator/Creator: Minerals Management Service

Dataset Title: MMS Ship Transect Survey for Mammals and Seabirds, Southern California Bight

Dataset Series Name: OBIS-SEAMAP

Dataset Release Date: 2006-03-21 17:43:40-05

Dataset Release Place: http://seamap.env.duke.edu/

Dataset Publisher: OBIS-SEAMAP

Data Presentation Form: vector digital data

Online Resource: http://www.mms.gov/

Parent DIF

This data set description is a member of a collection. The collection is described in
OBIS-SEAMAP

Temporal Coverage

Start Date: 1975-01-06

Stop Date: 1978-03-29

Location Keywords

OCEAN > ARCTIC OCEAN

OCEAN > PACIFIC OCEAN > NORTH PACIFIC OCEAN

GEOGRAPHIC REGION > POLAR

CONTINENT > NORTH AMERICA > UNITED STATES OF AMERICA > CALIFORNIA

Data Resolution

Latitude Resolution: 0.000167 Decimal degrees
Longitude Resolution: 0.000167 Decimal degrees
Horizontal Resolution Range: 1 meter - < 30 meters

Science Keywords

BIOLOGICAL CLASSIFICATION > ANIMALS/VERTEBRATES > BIRDS