In New Zealand commercial fisheries, captures of protected marine species are monitored at sea by Government observers. Observers are placed on selected vessels by the Ministry for Primary Industries and the Department of Conservation. Observers collect information on any protected species captures that occur during the fishing,
These pages contain data on observed captures of seabirds, marine mammals, and turtles from 2002–03 to 2017–18. The data cover all trawl, longline, set net, and purse seine fishing within the New Zealand Exclusive Economic Zone during this period. The observed captures will be used to estimate total captures across all (observed and unobserved) commercial fishing, using statistical modelling.
The core data are the records of observed captures. These are animals reported by fisheries observers as captured and then either released alive or landed dead. Observed captures do not include cryptic mortality (e.g., birds killed by warp strikes, but not brought on board the vessel ). Captures also do not include seabird deck strikes (such as birds whose deaths were unrelated to the deployment of fishing gear per se) or animals captured in a decomposing state (as these were assumed to have died of causes unrelated to the observed fishing effort).
A status of ‘dead’ or ‘alive’ reflects the animal’s state on capture or release (if alive). The status of ‘alive’ does not indicate a prognosis for survival after release.
When birds are captured they are identified by the observer, to the extent that the observer is able. Dead animals may subsequently be returned to the Department of Conservation for necropsy. This allows an accurate identification to be made. Since 2010, observers have routinely photographed captured animals, and these photographs allow expert identification to be made.
As expert identifications often differ from the observer identification, an imputation process has been used to correct observer identifications (based on comparing observer and expert identifcations of the same animals). This is particularly important for seabirds, as observers are often not able to identify them to the species level.
The identification used in preference is the expert identification from the necropsy, then the identification made from the photographs, and then the identification from the imputation. If the imputed identification is different from the observer reported identification it is listed in the tables as imputed.
The scientific and common names follow the recommendations of the Ornithological Society of New Zealand checklist committee (2010).
Fishing effort may either be presented as events (individual tows for trawl fisheries, and sets for longline fisheries), or as tows (trawl fisheries), and hooks (longline fisheries). Fishing effort is not shown on the maps or reported in tables where the fishing is by fewer than three vessels.
Fisheries are defined by the fishing method and the target species (the fish that the fishing was intending to catch). When defining the target fishery, the target species reported by the fisher from each fishing event s used. In some cases the target species was missing, or else an unusual target species was reported. In these cases the fishery was assigned based on fishing by the same vessel with a defined fishery.
The following fisheries were used for summarising the data. The codes in brackets are three letter codes used by the Ministry of Fisheries.
Observers are placed on selected vessels by the Ministry for Primary Industries. Observers are not present on all vessels. Fishing effort is therefore categorised as observed or unobserved in the figures and tables. The observed fishing may be reported either as an amount of fishing effort, or as observer coverage (the proportion of fishing effort that was observed).
A set of areas were developed for summarising the fishing effort and the protected species captures. These areas were chosen for the purpose of grouping related fishing effort together, and are not the Fishery Management Areas. A map showing the areas is available here, and may be downloaded as an ArcGIS shapefile.
In general, Ministry for Primary Industries fishing years run from 1 October to 30 September, and at this stage all captures are reported by fishing year. In places such as plots, where only a single year is given, this refers to the second year in the period. For example, 2010 refers to the 2009/10 fishing year, covering the period from 1 October 2009 to 30 September 2010.
For some fisheries, such as Southern Blue Whiting a different fishing year is usually used. The data may also be viewed by calendar year.
Data are made available for reuse by the Ministry for Primary Industries and the Department of Conservation, under a creative commons attribution licence, following the recommendations of NZGOAL. Figures are available under the same licence, but copyright Dragonfly Science. This licence allows the figures and data to be used for any other purpose and republished, provided only that attribution is given to the source. At the bottom of each page, a citation is given with a preferred format for referencing the data.
Each release of the data has a version number. The data are subject to change if any errors are found, or when further analysis is carried out in subsequent years. Any changes to the data will be accompanied by the release of a new version. Including the version number in citations will allow for reference to the data as they were when the version was published.
Creative commons images have been sourced to illustrate each species. These may also be reused, subject to the conditions of the original licence.
We are especially grateful to the many observers who have collected these data. This analysis was carried out through Ministry for Primary Industries project SEA2013-08: Data Preparation for protected species bycatch.
Abraham, E. R., & Thompson, F. N. (2011b). Summary of the capture of seabirds, marine mammals, and turtles in New Zealand commercial fisheries, 1998–99 to 2008–09. New Zealand Aquatic Environment and Biodiversity Report No. 80. 170 pages. Download from Ministry for Primary Industries.
Ornithological Society of New Zealand checklist committee (2010). Checklist of the birds of New Zealand, Norfolk and Macquarie Islands, and the Ross Dependency, Antarctica. Ornithological Society of New Zealand and Te Papa Press, Wellington, New Zealand. 500 p.