Marine mammal sightings on Canada's Pacific coast, 2004-2008

Raincoast Conservation Foundation, University of Victoria, and Dalhousie University. At minimum, please cite Harvey et al. 2017, Best et al. 2015, and Williams & Thomas 2007 if using these data.

Global biodiversity is undergoing rapid decline due to direct and indirect anthropogenic impacts to species and ecosystems. Marine species are experiencing accelerated population declines leading to many species being considered at-risk by regional, national, and international standards. As one conservation approach, decisions made using spatially explicit information on marine wildlife populations have the potential to facilitate recovery and contribute to national and international commitments towards conservation targets. Mapping both the distributions and densities of species at-risk can inform future Marine Spatial Planning (MSP) and conservation efforts, including the identification of Marine Protected Areas (MPAs). The goal of this research was to map spatially continuous distributions and densities of nine marine mammal species to support coastal conservation and marine planning in British Columbia, Canada. In this study, marine mammal sightings from systematic line transect surveys were integrated with remote sensing variables using Generalized Additive Models (GAMs) to predict distribution and density for the north coast of British Columbia. Density estimates for each segment of the survey transects were calculated using Multiple Covariates Distance Sampling (MCDS; Best et al., 2015) which were then included in the GAM predictions. The final product of this work adds and expands upon existing marine mammal data by providing predicted species distributions and densities for unsampled areas of the north coast. Contributions from this study provide GIS data products for informing coastal management decisions and open access data to further marine mammal conservation and research.

N/A

This dataset does not include visual sighting records as of August 2017. Surface density estimates and transect density estimates are available as supplemental layers for viewing. These layers are included in the downloadable zip file (the layer for point sightings is empty). To download, choose "Dataset on Dataset Page" and "As shapefile" options through the download wizard. The density layers are not downloadable individually.

Marine mammal line-transect surveys were collected by Raincoast Conservation Foundation using Distance Sampling from 2005 to 2008. The data are provided as (1) density estimates along 1 nautical mile transects generated using Multiple Covariates Distance Sampling (MCDS) and (2) predicted density estimates per ~14km2 hexagon were calculated using Generalized Additive Models (GAM). Note, the hauled out and in water sightings for both harbor seal and Steller sea lion were collated to maximize sample size.

Species abbreviations:
-DP = Dall’s porpoise (Phocoenoides dalli)
-FW = Fin whale (Balaenoptera physalus)
-HP = Harbor porpoise (Phocoena phocoena)
-HS_haulout = Harbor seal (Phoca vitulina) hauled out sightings
-HS_inwater = Harbor seal (Phoca vitulina) in water sightings
-HW = Humpback whale (Megaptera novaeangliae)
-KW = Killer whale (Orcinus orca)
-MW = Common minke whale (Balaenoptera acutorostrata)
-PW = Pacific white-sided dolphin (Lagenorhynchus obliquidens)
-SSL_haulout = Steller sea lion (Lagenorhynchus obliquidens) hauled out sightings
-SSL_inwater = Steller sea lion (Lagenorhynchus obliquidens) in water sightings

(1) Marine Mammal density estimates along 1 nautical mile transect segments using Multiple Covariates Distance Sampling (MCDS).

Field names:
-“SegID” = unique line transect segment ID. Can use this field to join across species files.
-“Date” = year-month-day
-“Latitude”
-“Longitude”
-“Dhat = estimated density (number of individuals per km2) estimated using Multiple Covariates Distance Sampling (MCDS).

(2) Predicted density estimations per hexagon (approx. 14km2). Note: hauled out and in-water species estimates were collated for prediction.

Field names:
-“hexagonID” = unique hexagon cell ID. Can use this field to join across species files.
-“density” = predicted species density (number of individuals per km squared). Derived using a Generalized Additive Model (Harvey et al., 2017).
-“norm_den” = Normalized density value generated by dividing the predicted density values (“density”) by the maximum predicted value for each species. Normalized density values range between 0 and 1.

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	Unique ID number (generated by OBIS-SEAMAP)
fid	Internal Field ID
obs_time	Time of the sighting (local time) added by OBIS-SEAMAP
obs_date	Date of the sighting added by OBIS-SEAMAP
obs_count	Group size added by OBIS-SEAMAP
species	Species name recorded
sp_tsn	Taxonomic Serial Number added by OBIS-SEAMAP
longitude	Longitude in decimal degrees
latitude	Latitude in decimal degrees
geom	Geometry field added by OBIS-SEAMAP