Ontogeny of movement patterns in naïve grey seal pups inhabiting a complex continental shelf ecosystem
Data files
Sep 18, 2023 version files 3.47 MB
-
2016PupDeployments-Locations.csv
-
2016PupDeployments-PupData.csv
-
README.md
Abstract
Most vertebrate offspring must transition from the relative security of parental care (nutrition and protection) to independent foraging. Offspring face many challenges during this critical period, particularly in species where parental care ends at weaning, such as the grey seal (Halichoerus grypus). We studied the development of movement behaviour in naïve grey seal pups from their first trips to sea to about five months of age. Twenty-five (12 males and 13 females) newly-weaned pups were fitted with satellite-linked GPS tags on Sable Island, Nova Scotia, Canada in January 2016. The influence of fixed effects (pup size, sex, week) and the random effect of pup identity on trip characteristics were examined. Movement behaviour was analyzed using a move persistence mixed-effects model. Habitat use was highly variable among individuals and covered much of the geographic distribution of the population. Unlike older juveniles, subadults, and adults in this population, most naïve pups used multiple haulout sites to begin and end trips. There was little evidence of area-restricted search behaviour during trips, suggesting that naïve pups were using an opportunistic foraging tactic that may result in more variable foraging success than that of older, experienced animals. Naïve pups made longer trips with longer haulout durations between them than observed for older greys seals. Males and females differed in some trip characteristics, but sex effects were small over the first few months of life. Offspring size at weaning was not a useful predictor of trip characteristics. Move persistence of grey seal pups was initially high and then decreased over time as individuals gained experience. Both intrinsic and extrinsic factors were influential on the movements of grey seal pups. Greater body length at weaning, longer duration spent on shore after weaning, shallower water column depth, and farther distance from shore were all associated with lower move persistence. Female grey seal pups had lower move persistence than males. Overall, the movements of naïve grey seal pups during the first few months of life were characterized by extensive exploration, but move persistence decreased over time suggesting they may be using an exploration-refinement foraging tactic.
README
DFO Sable Island Grey Seal Pup Project
Twenty-five newly-weaned pups were fitted with satellite-linked GPS tags on Sable Island, Nova Scotia, Canada in January 2016. We studied the development of movement behaviour in naïve grey seal pups from their first trips to sea to about five months of age. We explored the influence of intrinsic factors on the trip characteristics and move persistence of grey seal pups and how their movement behaviour changed over time.
Description of the data and file structure
The data for this project includes two files:
(1) 2016PupDeployments-PupData.csv
This file includes the biometric data collected on grey seal pups selected for inclusion in this study with the following columns:
DeployID - unique identifier for each individual grey seal included in the study
PTTID - Argos Platform Transmission Terminal identifier, which is a unique number identifying each Mk10-AF Fastloc GPS tag
SerialNo - serial number for each Mk10-AF Fastloc GPS tag
Cohort - year grey seal pups were born where 2016 corresponds to December 2015/January 2016
Sex - individual sex where male = 1 and female = 2
WeanDate - the date each grey seal pup was weaned
WeighDate - the date each grey seal pup was weighed
WeanWeight - the mass (kg) of each grey seal on the WeighDate
StdLength - the standard length (cm) of each grey seal at the time of instrumentation
TagDeployment - date the Mk10-AF Fastloc GPS was instrumented on each grey seal pup
Comments - any additional comments regarding data transmission
(2) 2016PupDeployments-Locations.csv
This file includes the Fastloc GPS and Argos locations collected by grey seal pups instrumented with Mk10-AF Fastloc GPS tags (www.wildlifecomputers.com) with the following columns:
DeployID - unique identifier for each individual grey seal included in the study
PTTID - Argos Platform Transmission Terminal identifier, which is a unique number identifying each Mk10-AF Fastloc GPS tag
Instr - Wildlife Computers instrument family
Date - date and time (AST) of each location
Type - type of location, either GPS (Fastloc GPS) or Argos
Quality - class of location generated by Argos for the satellite pass containing this message - values in ascending order of quality are "Z", "B", "A", "0", "1", "2", "3"
Latitude - latitude of the location
Longitude - longitude of the location
Sharing/Access information
This project was financially supported by the Department of Fisheries and Oceans, Canada and The Ocean Tracking Network, Dalhousie University, Halifax, Nova Scotia.
All sampling protocols were conducted in accordance with the requirements of the Canadian Council on Animal Care and were approved by Fisheries and Oceans Canada's Maritime Region Animal Care Committee (protocol number 15-27) and Dalhousie University’s Committee on Laboratory Animals (protocol number 15-115). Work was undertaken under the Parks Canada Agency Research and Collection Permit SINP-2012-12974.