Appendix A — Commercial fisheries data

New Zealand’s fisheries management system recognises three catching sectors:

commercial fishers;
recreational/amateur fishers; and
customary fishers.

This chapter provides:

a brief introduction to the data submitted by commercial fishers since the establishment of the Quota Management System; and
references to documents that users of the kahawai database should be familiar with before using these data.

A.0.1 Data sources

Data on fishing effort, catch, and landings were originally collected on paper forms and managed in the warehou database. The structure of the kahawai database is based on the warehou tables, reflecting the concept that fishing events take place within trips that culminate in landing events (Figure A.1).

flowchart TD
    A(Fishing trip)
    A --> B(Fishing events)
    B --> C(Estimated catches)
    A --> D(Landing events)

Figure A.1: The general structure of commercial fisheries data collected in New Zealand.

Beginning in 2008, the collection of data from New Zealand commercial fisheries transitioned to an Electronic Reporting System with the data collection defined by a series of circulars.

Fisheries data are currently stored in MPI’s Enterprise Data Warehouse (EDW) which implements a dimensional fact model (DFM) format.

A.0.2 Data processing and grooming

All fisheries research publications should document the data sources used and how these data have been processed for use in the analyses reported. Over time, researchers have converged on particular data treatments that are generally accepted as ‘best practice’; these are what the kahawai database aims to implement.

Generic data treatments for the catch, effort, and landings data were first documented by Starr (2007). Later, Bentley (2012) developed a systematic approach for applying the rules proposed by Starr (2007), and subsequent developments.