2 Fisheries Oceanography Database

2.1 Data sources

The ctd (fisheries oceanography) database contains some physical oceanography data collected during trips conducted by the Marine Research Group of the Ministry of Agriculture and Fisheries, and later NIWA. Much of the data collected were obtained using a conductivity, temperature, and depth (ctd) probe, hence the name of the database. The data on the ctd database were collected during trips conducted between 1982 and 1993, and from 2002 onwards. It may be necessary to alter the structure of the database later to allow for the storage of data from mechanical bathythermographs (MBT) and expendable bathythermographs (XBTs).

The database has been set up in accordance with Marine Research Computing database standards (Ng 1992).

2.2 Uses of the ctd Database

Physical oceanographic features such as thermoclines and upwellings affect the distribution and availability of fish. Data from the ctd database can be used to locate and study the nature of water masses, currents and temperature fronts. These data can also be used to describe the physical environment where fish are found.

The ctd database is designed to be used in conjunction with other data collected during research trips, such as catch rates, catch composition, etc, to assist in the interpretation of trends in species abundance. Since these data also span a range of seasons and years in many areas of New Zealand they can also assist in trip planning.

2.3 Trip, cruise, or voyage?

Over the years, trawl surveys have been labelled many things. In the last few years research surveys have been called "trips", "cruises" or "voyages", but all represent the same thing.

As a consequence, while the trawl database labels all trawl surveys and associated tables with the word "trip", the words "cruise" or "voyage" can just as easily be substituted.