Temperature data from CTD profiles. Different instruments used. Early period - surface bucket, mid-period: PML built instrument, Later period using SeaBird SBE19+. Bucket temperature corrected for early series (1988-2001) by using overlap of PML CTD profiles surface temperature: (bucketT - 0.625359)/0.987653. Bucket temperature corrected for in later series (2002-2011) by using overlap of PML CTD profiles surface temperature: (bucketT - 0.164208)/0.989273.Salinity data from CTD profiles using PML CTD (1996 - 2001) SeaBird SBE19+ (2002-2011). Data corrected for the early period (1996-2001) based on the median salinity at 50 m and applying an offset. Whole cast of data removed if 50 m depth salinity during 1996-2001 falls outside the maximum and minimum salinity at 50 m determined during 2002-2011.