| Title | Processed CTD data from the Pelagic Biomass Survey on the Africana Voyage 290, October 2016 |
|---|---|
| Project | Pelagic Biomass Survey |
| Authors |
Marcel van den Berg |
| Publisher | Department of Forestry, Fisheries and the Environment (2017) |
| Contributors |
Contact Person: Marcel van den Berg |
| Abstract | This is processed Conductivity, Temperature, Depth (CTD) data from the Pelagic Biomass Survey on the Africana Voyage 290 from 25 October - 14 December 2016. The cruise operated from Hondeklip Bay to Port St Johns, South Africa.The principal aim of the Pelagic Biomass Surveys is to obtain estimates of the total biomass of anchovy, sardine and west coast round herring and to obtain data on their population length frequency compositions, for input to the operational management procedure (OMP) for making Total Allowable Catch (TAC) recommendations for the following year. The surveys also obtain information on the environment and food regime impacting anchovy, sardine and west coast round herring around the coast, although recent surveys (~2009 onwards) have included much less environmental sampling than earlier years. The survey uses hydro-acoustics to estimate fish density and abundance, and midwater trawling to identify acoustic targets and to obtain length frequency and other biological data, and ichthyoplankton and environmental sampling are also conducted. The abundance and biomass estimates from these surveys are an essential input into the management process and serve as a scientific basis for the setting of TAC recommendations for the small pelagic fishery. The area covered by the pelagic surveys extends over much of the continental shelf around South Africa, and initially extended from Hondeklip Bay on the west coast to Port Alfred on the south coast, but has extended further east in some recent years. This dataset was processed using older standards which may not align with international best practices and the standards currently adhered to by the Department of Forestry, Fisheries and the Environment (DFFE). The Department is re-processing and replacing data to ensure everything has the same format and is of the same quality and datasets will be marked as obsoleted once that is done. As such the user assumes the entire risk related to the use of these data in its current state and format. DFFE disclaims all warranties of the data whether expressed or implied, including without limitation, any warranties of merchantability or fitness for a particular purpose. For any concerns regarding the data, the user may decide to liaise with the listed PIs who will share their insight on the data quality, where possible. It is also strongly recommended that the user liaises with the listed PIs regarding their proposed projects to mitigate against duplication of research efforts. |
| Methods | The CTD raw data was converted to scientific units using SBEDataProcessing software (ver 7.26.7.114). The following modules (SBEDataProcessing) were then run on the converted data using the recommended default values: Align CTD, Filter, Loop Edit and Cell Thermal Mass. The data was then split into the up cast and the down cast. The down cast data was then bin averaged on pressure, every 1db. |
| Data | |
| Temporal extent | 26 Oct 2016 – 14 Dec 2016 |
| Geographic extent |
Hondeklip Bay, Port St Johns, South Africa
North: -30.0 |
| Keywords | Africana, Africana 290, Conductivity, CTD, Depth, INDIAN OCEAN, SOUTH ATLANTIC OCEAN, Temperature |
| Related resources |
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