The trawl database is the major fisheries research database. It results from data collected by research trawl surveys on research vessels and chartered commercial fishing vessels. This database is maintained by NIWA for MPI. Trawl surveys are a major tool used by research scientists for stock assessment. They are used to estimate basic parameters of commercial fish populations, including biomass, sex ratio, and the proportion of sexually mature fish, and the distribution of ages and lengths in the population. These parameters may be used in estimating mortality and growth rates. Sampling frequency: variable. Database records start in 1960 and continue to present. Number of sites: variable. Extent of site: entire EEZ and beyond. Lat/Long provided for all data. Number of replicates: N/A. Measured variables: Data include sea temperature, depth, location, fishing vessel, date, catch weight, species, trawl speed, trawl time, weight of each fish species caught, and length, sex and age data for selected species. Sampling protocol & QA: inshore and deepwater research trawl surveys conducted in New Zealand waters. In addition to the trawl information other information collected during trawl surveys are also included in the database e.g. camera deployments, CTD probes, plankton, physical measurements, blue cod potting. Depth range: 2 to 3500 m.