Since 1991, the Department of Conservation has monitored NZ fur seal pup production at three breeding colonies on the West Coast – Wekakura Point, Cape Foulwind and Taumaka (Open Bay Islands). Pup production estimates are derived using both a mark-recapture methodology and direct counts of dead pups. The mark-recapture exercises take place in the last week of January each year.
At Taumaka Island, the largest of the Open Bay Islands and the furthest south of the three colonies being monitored, up to 800 pups are marked each year with the first 100 pups of each sex weighed and measured.
At Cape Foulwind, Westport, up to 200 pups are marked each year, with the first 50 of each sex weighed and measured.
At Wekakura Point, the furthest north of the monitored colonies, up to 500 pups a year are marked, with the first 75 of each sex weighed and measured.
The original data were recorded in two spreadsheets per colony per year: one containing marking and measurement data, and another with mark-recapture counts and pup production estimates. Data from the annual spreadsheets were combined and transferred into three spreadsheets (one each for tagging, mark-recapture, and dead counts) at the Department of Conservation, and then groomed further by Dragonfly Science to complete missing data and correct inconsistencies. A record was kept of all changes to the data. These changes are visible from individual tagging events, by following the details link. A record of all updates is available as a CSV file.
Data are made available for reuse by the Department of Conservation, under a creative commons attribution licence, following the recommendations of NZGOAL. This licence allows the data to be used for any other purpose and republished, provided only that attribution is given to the source.
All reports or presentations using the West Coast data must acknowledge:
DOC staff and volunteers, especially Hugh Best, who have been involved in the fieldwork over the years, and
The landowner Taumaka me Popotai Trust, for allowing DOC access to Taumaka.
At the bottom of each page, a citation is given with a preferred format for referencing the data.
This database was developed by Finlay Thompson and Richard Mansfield of Dragonfly Science. We are grateful to all the scientists who have collected these data, most recently Hugh Best, who coordinates the population monitoring programme. We also gratefully acknowledge the ongoing support for the West Coast fur seal pup counts provided by DOC Regional and District staff, Tai Poutini Papatipu Runanga and the trustee owners of Taumaka me Popotai. The development of this database was funded by the Department of Conservation's Marine Species and Threats team project focusing on improving accessibility to data.
For information about the New Zealand fur seal monitoring programme please contact the Department of Conservation's Marine Species and Threats Team (marine@doc.govt.nz). To report problems with the website, or for queries about the data grooming and preparation, please contact Finlay Thompson (finlay@dragonfly.co.nz).
Filters are typed into the search box as a key, followed by a colon,
followed by a value. For example year:2002 restricts the data to
pups that were tagged during 2002. Filters that are applied will
appear above the search box, and may be removed by clicking on the
cross beside them. Recognised filter keys are listed below:
from: Finds pups tagged on or after a date given in YYYY-MM-DD
format. For example: from:2002-02-02
to: Finds pups tagged on or before a date given in YYYY-MM-DD
format. For example: to:2003-03-03
year: Finds pups tagged in a calendar year. For example, entering
year:2003 will set the from date to 2003-01-01 and the to date to
2003-12-31.
month: Finds pups tagged in a calendar month. For example,
entering month:2003-04 will set the from date to 2003-04-01 and
the to date to 2003-04-30.
day: Finds pups tagged on the given day. For example, entering
day:2003-04-05 will set both the from and to dates to 2003-04-05.
tag: Finds pups associated with the given tag. This filter
expects a colour, shape, and tag number, in that order, separated by
colons. For example, tag:orange:button:1234 specifies the tag
with the colour blue, the button shape, and number 1234.
Components of the tag search can be left out and replaced by a
question mark. For example, to search for all tags with the number
4321, enter tag:?:?:4321.
Unknown digits in the tag number can also be given as a question
mark, for example, tag:orange:button:123? finds all orange button
tags with numbers starting "123"; tag:white:?:2?7? finds white tags
whose numbers start with 2 and have a 7 in the third position.
colour: Finds tags with the given colour. This filter has the
same effect as the first element of the tag filter.
shape: Finds tags with the given shape. This filter has the
same effect as the second element of the tag filter.
number: Finds tags matching the given number or partial number.
This filter has the same effect as the third element of the tag
filter.
notches: Finds tags exactly matching a given set of edge-notch
positions. For example, notches:2,3 finds tags with edge notches
in both the 2 o'clock and 3 o'clock positions; notches:6 finds
tags with an edge notch in the 6 o'clock position only, but it will
not find tags notched at both 6 and 7 o'clock) (see below);
notch: Finds all tags with an edge-notch in the given position.
For example, notch:2 finds all tags that have an edge-notch in the
2 o'clock position, including tags with additional notches in other
positions.
cap: Finds caps matching the given number.
location: Restricts the search to sightings at the given location,
for example: location:sector-4.
colony: Restricts the search to sightings at the given colony. Recognised values are wekakura-point, cape-foulwind and open-bay-islands.
sex: Finds pups of the given sex. The value must be one of M, F, or U (unknown).
event: By default, searches will return both tagging and
resighting events. To show tagging events only, use event:tag; to
show resighting events only, use event:resight.
Tags: Tags are identified by colour and shape, followed by a number.
At each of the three colonies, different coloured tags are given to male and female pups. Valid tag shapes are 'disc' and 'button'. The following tag types appear in the database:
Tag numbers are either a four-digit number, or an 'A' followed by a three-digit number.
Status of the tags at resighting.
L0,R0: No tags present.
L?,R?: The number of tags remaining is unknown, or was not recorded at the time of sighting.
L1,R1: Two tags recorded.
L1,R0: Left tag only.
L0,R1: Right tag only.
L1,R?: Left tag remaining, right flipper not seen.
L?,R1: Right tag remaining, left flipper not seen.
L0,R?: No left tag; right flipper not seen.
L?,R0: No right tag; left flipper not seen.
1 tag: One tag recorded. Not noted whether the tag was seen in the left or right flipper.
RECOV X1: Single tag recovered.
RECOV X2: Two tags recovered.
Tag notches: Since 1993, the tags have been clipped across the top and then edge notched to signify the year of tagging, in case the pigment or the identity numbers becomes indecipherable with time.
Numbers listed under the Notches column refer to the clock positions of any notches with respect to the writing on the face of the tag. In most cases, notched tags also have a straight piece cut off the top of the tag to indicate the 12 o'clock position.
Mark-recapture experiments are a way of estimating the pup population at a breeding site when the size of the colony precludes direct counts of the pups.
A known number of pups are marked with flipper tags, or by clipping fur on the pup's forehead. On subsequent days a series of recapture counts of both marked and unmarked pups is performed. The ratio of marked to unmarked pups may then be used as the basis for estimating the entire pup population.
Each season, dead pups are usually counted immediately before pups are marked for the mark-recapture counts. These dead counts do not represent all of the pup mortality that may have occurred prior to the mark-recapture experiment, because these colonies are infrequently visited. However, an estimate of total pup production for the season can be obtained by adding the number of prior dead pups to the mark-recapture estimate of the live pup population.
Dead pups are also recorded as they are found during the recounts. Freshly dead marked pups found during recounts are taken into account when calculating the live pup estimate.