SMRU Grey Seal UK 1991-1993

Sea Mammal Research Unit (SMRU), University of St. Andrews

The movements of 14 grey seals Halichoerus grypus Fab. caught at the Farnes in north-east England (n = 12) and Abertay in eastern Scotland (n = 2) between August 1991 and July 1993 were investigated using Argos Satellite Relay Data Loggers (SRDL). The data are a spreadsheet of points representing seal locations. The low and irregular uplink rate from an SRDL on a seal to the Argos satellites can result in potentially significant errors in some location fixes. Therefore, locations were filtered using an algorithm based on a [maximum speed parameter] of 2 m s-1. This filter rejected 17% of the primary locations that would have required an unrealistic rate of travel to achieve. However, this does not remove all invalid locations hence there are still some data points occurring inland. There are 9,454 locations in the spreadsheet covering all months of the year except February and March.

Grey seals Halichoerus grypus Fab. are large, numerous marine top predators. The British population in 1994 was estimated to be 108,000 individuals and it has been steadily increasing since. Fears concerning competition with fisheries have prompted calls for control measures under the UK Conservation of Seals Act 1970. However, little is known about the areas where grey seals forage or of the distances they may travel. Management must be based on an understanding of the complex seal-fishery interactions, a component of which is having information on the temporal and spatial distribution of seals.

N/A

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.
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Attributes in dataset

Attribute (table column)	Description
series	Tag ID
date	Date of the observation
time	Time of the observation
latitude	Latitude in decimal degrees
longitude	Longitude in decimal degrees
lq	Location quality
species	scientific name
geom	Geometry field added by OBIS-SEAMAP
oid	Unique ID number (generated by OBIS-SEAMAP)