Aquatic Species Distribution Database

Aquatic Species Distribution Database,

a collaboration between ALCOM, the J.L.B. Smith Institute and WWF

The Aquatic Species Distribution Database (ASD) was conceived in order to recommend the use of appropriate species for stocking to avoid transfer of alien species between different catchments. It has evolved however to a much more powerful instrument for ecologists and zoogeographers based on information from a number of important museum collections from inside and outside the region.

This project is driven by Dr. Paul Skelton, Director of the J.L.B. Smith Institute in Grahamstown (South Africa), who is providing ALCOM with records from the most important museum collections on fish species in Southern Africa. Collection records which are already included or are planned to be included originate from:

  • J.L.B. Smith Institute, Grahamstown (South Africa)
  • Albany Museum, Grahamstown (South Africa)
  • Michigan Museum, Michigan (USA)
  • Bulawayo Natural History Museum, Bulawayo (Zimbabwe)
  • Namibia Museum, Windhoek (Namibia)
  • Royal Museum for Central Africa, Tervuren (Belgium)
  • Royal Ontario Museum, Toronto, Ontario (Canada)
  • Various biomonitoring datasets (e.g. NAEBP in South Africa)

ALCOM's task in the ASD project is to integrate the collections in a GIS, based on ALCOM's watershed model for Southern Africa. Through an overlay of the locations where certain fish species have been found and the subwatersheds, distribution polygons are determined. These polygons have to be checked by the J.L.B Smith Institute for possible errors or inaccuracies. When this will be done, digital species distribution mapping will be available, including historical changes in species distribution which might be reflected in the collections. On top of this, the method offers a unique chance to verify records for possible errors in geographical locations.

The interface and methods for the digital species distribution mapping have been developed already and we are currently merging the different databases and checking for errors in locations. Some examples of the first distribution mapping are given below.

Figure 1: Distribution points of Orechromis mossambicus in the JLB Smith and Alabany Museum collections:

The distribution of Oreochromis mossambicus according to the records in the JLB Smith and Albany museum collections is first plotted as points on the map. One can observe the high collection rate in certain areas whilst in others, very few specimens of Oreochromis mossambicus were recorded. This is partly related to the fact that O. mossambicus is not considered by many collectors as an interesting species for museums and thus not often sent for determination in contrast with some of the smaller and more difficult species (such as many Barbus spp.).

After checking for obvious erratic locations, the records are overlayed with the catchment map (subwatersheds) and the subwatershed ID for each record is linked to the species record. This enables one to export a datafile and crosstable with all the Watershed ID's for each species in order to visualise a digital distribution map.

Figure 2: Distribution of Oreochromis mossambicus based on an overlay of distribution records from JLB Smith and Albany museum with the ALCOM-WWW watershed polygon layer. The table on the right indicates the number of records in each watershed.

Oreochromis mossambicus distribution polygons

For more information contact:

The Fisheries Officer, ALCOM
Mail:       PO Box  3730, Harare, Zimbabwe
Location :  Fisheries Research Unit, National Parks Complex,
            Sandringham Drive, Harare, Zimbabwe
Telephone: 263-4-734797, 724985
Fax:       263-4-736847
Telex:      260-40 FAO ZW

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