Name: Processed CTD discrete observations from the West Coast Hake Biomass Survey on the Africana Voyage 075, July 1989
License: https://creativecommons.org/licenses/by-sa/4.0/

DOI: 10.15493/DEA.MIMS.11692023

Title	Processed CTD discrete observations from the West Coast Hake Biomass Survey on the Africana Voyage 075, July 1989
Project	West Coast Hake Biomass
Authors	Mbulelo Makhetha Oceans and Coastal Research, Department of Forestry, Fisheries and the Environment (DFFE); role: Marine Scientific Technician; contact details: email: MMakhetha@environment.gov.za Gavin Tutt Oceans and Coastal Research, Department of Forestry, Fisheries and the Environment (DFFE); role: Marine Scientific Technician; contact details: email: Gtutt@environment.gov.za Tarron Lamont Oceans and Coastal Research, Department of Forestry, Fisheries and the Environment (DFFE); role: Marine Scientist; contact details: email: tlamont@environment.gov.za
Publisher	Department of Forestry, Fisheries and the Environment (2023)
Contributors	Contact Person: Gavin Tutt Oceans and Coastal Research, Department of Forestry, Fisheries and the Environment (DFFE); role: Marine Scientific Technician; contact details: email: gtsglider@gmail.com
Abstract	Here we present processed Conductivity-Temperature-Depth (CTD) discrete data from the upcast collected between 14 July and 17 August 1989 during Voyage 075 on the FRS Africana, in the Benguela Current Large Marine Ecosystem (BCLME) region on the west coast of Southern Africa. Neil Brown MK3 and MK4 CTD instruments were used to measure pressure, temperature and conductivity through the water column during research and monitoring cruises between 1983 and 2000. The objectives of the West Coast Hake Biomass Survey were to survey by means of trawling the abundance of adult and recruiting hake in South African waters; to investigate the diurnal cycle of hake and other demersal species; to investigate the environmental and ecological interrelationships of hake and demersal species; to make some experimental trawls in deep water to determine hake distribution limits and to collect deep-water specimens of fish and squid; to collect routine biological material on demersal species from South West African waters; to investigate the occurence, distribution and abundance of squid and squid larvae; to study demersal community interrelationships; to study the biology of sharks and selected non-commercial fish species; to investigate zooplankton scattering layers and their influence on the feeding behaviour of small hake and to extend the primary production data further offshore as well as north and eastwards from the Cape Peninsula - Cape Columbine area.
Methods	Neil Brown MK3 and MK4 Conductivity-Temperature-Depth (CTD) instruments were used to measure pressure, temperature and conductivity through the water column during research and monitoring cruises between 1983 and 2000. Temperature was converted from the IPTS-68 scale to the ITS-90 scale, and salinity was computed from conductivity measurements on the 1978 Practical Salinity Scale, according to UNESCO (1991) algorithms. UNESCO (1993) quality control procedures were applied to the data, and obvious erroneous values resulting from problems including electronic spikes, data collection in air, inadequate flow through the conductivity cell, among others, have been removed. Any additional calibrations or corrections have been specified in each data file, where applicable and available.
Data	Attribution-ShareAlike 4.0 International (CC BY-SA 4.0) Cite 10.15493/DEA.MIMS.11692023 Style Terms of use These data are made available with the express understanding that any such use will properly acknowledge the originator(s) and publisher and cite the accession numbers and/or associated Digital Object Identifiers. Anyone wishing to use these data should properly cite and attribute the data providers listed as authors in the metadata provided with each dataset. It is expected that all the conditions of the data license will be strictly honoured. Use of any material herein should be properly cited using the dataset’s persistent identifiers such as accession numbers and DOIs. I agree to the terms of use
Temporal extent	14 Jul 1989 – 16 Aug 1989
Geographic extent	Benguela Current Large Marine Ecosystem (BCLME) North: -28.5 South: -36.0 West: 14.5 East: 20.0
Vertical extent	Max: -881 m Min: -0.01 m
Keywords	Africana, Africana 075, Conductivity, CTD, Depth, Neil Brown CTD, SOUTH ATLANTIC OCEAN, Temperature
Related resources	This digital object is described by https://unesdoc.unesco.org/ark:/48223/pf0000090489 This digital object is described by https://unesdoc.unesco.org/ark:/48223/pf0000138825 This digital object is part of West Coast Hake Biomass Survey on the Africana Voyage 075, July 1989 (10.15493/DEA.MIMS.11862023)

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