2 Kina Population Surveys
2.1 Data sources
This database results from the experimental fishing of kina
(Evechinus chloroticus) off Fiordland.
Recent surveys of kina in Dusky Sound revealed abundant stocks,
but insufficient information to predict sustainable yields from any
fishery (McShane & Naylor 1991). To gain a detailed stock
assessment of kina, a small number of fishers (participants) have
been granted permits to harvest 1000 tonnes per annum of kina between
them, commencing in the 1992-93 fishing year in Dusky Sound.
Fishing is restricted to free dive harvesting within the fishdown
area, with permanent non-fish (control areas) established within the
Sound. Each participant can have several divers fishing for them.
Small-scale records of catch and effort are collected from the
participants, which can be verified by scientific observers.
Observers also record morphometric data from random samples of the
During the survey, Marine Research divers from the Kina Research
Group regularly survey sites within the fishdown and control areas.
Stratified random surveys of kina in Dusky Sound (McShane et
al. 1993) were conducted prior to the commencement of fishing. These
surveys allow changes in kina stock structure and disturbances to the
marine community caused by fishing to be accurately assessed.
As at September 1993, these surveys may be repeated at other sites
within New Zealand, such as the Marlborough Sounds.
Data therefore come from three sources: (a) commercial catch and
effort, (b) the Scientific Observer Programme (SOP) catch sampling,
and (c) research dive surveys.
2.1.1 Commercial Catch and Effort
Each participant in the Kina Development Programme must complete
daily catch log sheets at the end of each fishing day. This log is
over and above the catch and effort landing returns that must also be
completed. On this daily log sheet the participant records the landed
catch weight, total time spent diving, and position for each catch
site used that day by a diver; i.e., there is one daily log sheet for
each diver. Hence, differences in catch and effort between individual
divers can be estimated. Catch and effort for kina landed from a
single dive site, but from multiple divers, are divided equally
between the divers concerned.
2.1.2 SOP Catch Sampling
Scientific observers present on fishing boats during the Kina
Development Programme collect biological data from the daily catches.
Each observer takes representative samples from a participant's
daily catch. Samples are taken only from catches that can be traced
back to a single dive site, and preferably from a single diver.
Samples from a single dive site and diver can be linked back to
the catch details as listed in the daily log sheet. Samples from a
single dive site but multiple divers cannot be linked back to any
catch details, but are still very useful in determining stock
From a sample, an observer collects two sets of information:
The observer collects length frequencies
of the commercial catch sample. This is achieved by measuring the
test (shell) diameter (to the nearest millimetre) of about 200
individual kina. Each length frequency sample contains header
information including, the participant's name, fishing date, grid
reference, diver's names (there may be more than one diver), etc.
The observers are also required to
provide information on kina morphometrics and biology (length/total
weight/roe volume). Observers are instructed to take a random sample
of 25 individual kina from the original sample of 200. For each
kina, observers measure the test diameter to the nearest millimetre,
weigh the whole animal to the nearest gram, record roe volume to the
nearest millilitre, and record the colour, hence quality, of roe on
a scale of 1 to 5 (with 5 representing top quality).
Observers also complete a daily catch log sheet, which is very
similar to the participant's log sheets.
Therefore, on most fishing days there are two sets of catch
information. The compulsory filling of the logs by the participants
ensures catch data for every fishing day, and the observer filled
catch logs allow verification of the participant's logs. The kina
database contains mostly observer collected catch data. Participant
catch data are substituted only when there is no observer coverage.
2.1.3 Marine Research Dive Surveys
At randomly selected sites within a defined area, currently within
Dusky Sound, two divers each descend to a randomly chosen depth (0-10
metres). Beginning in a randomly chosen direction, each diver turns a
1 metre square quadrat over 25 times. Each quadrat is thoroughly
searched and all kina are counted and collected. The collected kina
form the length frequency sample for that site.
For some sites, a sub sample of 20 kina are randomly selected from
the mature sized fish in the sample for a morphometric and biological
examination. Data are collected and recorded as for the SOP sampling.
2.2 Data Validation
While the kina database structure enforces data validation and
integrity with the use of referential constraints and range checks,
the data also goes through a rigorous data validation and error
checking process before being inserted.
The punched data are reformated using the checkq [See the local
Unix manual page on checkq] program, which performs range checks,
and the data are checked for invalid entries. The data are then
loaded into temporary tables in the database where cross checks are
made including checking that the grid references are valid, i.e., not
on land or in too deep water, nor outside the valid area. Strata are
allocated based on the grid references.
Each SOP sample is also checked to ensure it has an accompanying
catch record, and each biological record has a corresponding length