Presentation Structure

The challenge

GIS solution

Site suitability for Aquaculture

Spatial analysis options

Climate change

GIS future is Green

The ChallengeAnthropogenic influence

Population growth

Increase in pressure on land and ocean

Food insecurity & Poverty

Natural fish resources nearing depletion

Alternative food (protein) source to capture fisheries: Fish farming -

inland

African aquaculture 2% of global aquaculture production (5% of

Africa's fish)

GIS Solution

Aquaculture fastest growing agricultural sector globally

(>50% of fish)

Increase protein production

Reduce poverty

Increase food security

Existing resources (water, manure, food processing

mills, available land, smallholdings, dams)

Sustainability

Affordability (relatively low cost)

Small-scale farmer benefit

GIS Solution

Gauteng Department of Agriculture and Rural

Development (GDARD)

Phase 1: “Low cost Integrated Aquaculture

and Layer Hen’s Production Unit”

Pond, cage but not recirculating tank

production systems

Edible fish considered

Perception: Gauteng too cold/warm for

aquaculture

Site Suitability for Aquaculture

Fish species considered

Cold water fish:

Rainbow trout (Oncorhynchus mykiss)

Warm water fish:

Common carp (Cyprinus carpio)

African catfish (Clarias gariepinus)

Tilapia (Rendali, Oreochromis niloticus & mossambicus)


Mozambique tilapia

(Oreochromis Mossambicus)

Earth ponds (low cost)

Rivers, springs & boreholes

Cage culture

Dams, perennial pans

Current network of irrigation

systems in SA

60 000 ha of water

Large % might be suitable


Site suitability of Gauteng for inland fish farming

Spatial data integration concept

Spatial modelling in ArcGIS 10.1

Variables and thresholds - limiting or economic:

Water sources

Water temperature

Restricted areas

Infrastructure

Topography factors

Soil factors

Distance to processors

Site security

Spatial Analysis

Single expert knowledge in choosing parameters

Thresholds assigned to parameters

Parameters combined

Areas where all criteria were met

Yes/No answer

MSc thesis by Steer (2005)

Spatial AnalysisBuffering:

Distance from water source

Distance from substantial roads

Masks:

Wetlands

Built up areas

Eskom lines and substations

Water temperature

Slope

Population density and unemployment

High risk / Low risk (controversial)

Economic viability

Soil clay %

Soil pH

Distance to power lines

Distance from processors


Many other factors:

Sources of pollution

Water table heights

Occurrence of fish predators

Water quality

Proximity to chicken farms (manure), food

processing plants and waste (sewerage) water

Legislation

Distance to markets

Dam levels

Aspect

Land ownership

Flood zones

Seepage rates

Competition: other uses

Salinity

Input Criteria

Name of variable layer Source Threshold

Water sources SANBI, DWA, CDSM <= 1 km

Water Temperature

Grids

FAO AWRD database 20 - 30 oC

Tolerate 15 - 42 oC

Ideal 28 - 30 oC

Slope (for Ponds) Derived from SRTM

DEM, ARC-ISCW

0.5% – 2.5%

Population density Derived from

STATSSA census

data

>= 5000 p/km2

Unemployment rate Derived from

STATSSA census

data

>= 30%

Substantial roads Combination of

several road shape

files

<= 200 m

Fish processors Collected from

Google Earth

addresses and phone

calls

<= 100 km

GIS AnalysisModel Builder in ArcMap 10.1

Analysis Options

Multi Criteria Evaluation (MCE)

Weighting

Levels of suitability (classes)

Associated Yields

Multiple experts choosing

parameters

Delphi method

Based on Land-Types

Thematic layering in MS Access

Funding Options

Budget

Investment

Data and Tool OptionsFAO African Water Resource Database (AWRD)

Inland aquatic resource management

Spatial data archive and GIS-based tools:

Datasets covering the African continent: Surface water bodies, watersheds,

aquatic species, rivers, political boundaries, population density, soils,

satellite imagery, physiographic and climatological data

Custom-designed applications and tools programmed to run in GIS

software environment (ArcView 3.x)

Integration of different types of information in a GIS analytical

framework

To display and analyse

“Valuable instrument to promote food security”

Continental scale

Species DistributionMozambique tilapia endemic

Nile tilapia invasive species

Naturally occurring in coastal rivers of

Israel, Nile basin, various Ethiopian

lakes, West Africa other lakes and

river systems across Africa

Faster grower

Hybrids accumulate more Nile tilapia

genes over generations

Protect Mozambique tilapia from Nile

tilapia invaders

Preserving Pure O. Mossambicus

International Union for Conservation of Nature (IUCN) status of

Mozambique tilapia

2010 Least concern to near threatened as result of exotic Nile tilapia

introduction/invasion

No active steps by authorities in either Zimbabwe or South Africa to

protect established genetically unpolluted populations in reservoirs

No programmes to control established hybrid populations

Controversial zoning system proposed to allow Nile tilapia farming in

those regions where already present but not in regions where not

Environmental protection of local biodiversity

Promotion of the Mozambique tilapia as suited to small-scale

aquaculture in southern Africa

Climate ChangeGeophysical Fluid Dynamics

Laboratory (GFDL) Climate

model

Increase in water temperature

leads to increase in growth

Above 30 oC growth slows

down, death

Climate change adaptation of

the different species

Factors affecting water temp:

Air Temperature

ET (Potential

evapotranspiration)

Wind

Solar radiation

Future tilapia occurrence

Modelling Options

Model future species distribution

Ecological risk assessment

Based on feed & environment

Ecopath with Ecosim (EWE), Ecospace

MaxEnt

SANBI NFEPA fish sanctuaries

Sub-quaternary catchments

Characteristics of a Mozambique tilapia

sanctuary

Future fish sanctuary delineation

GIS Future is GreenSolving future problems now

GeoDesign: Integration of design tools with existing GIS functionality

Design for Anthropogenic elements of Earth systems

Understand the dynamics of the various systems

Develop robust models and tools

Planning framework that incorporates technology, science and nature

Choose the best alternative futures

Earth Systems Engineering and Management (ESEM)

ESEM: Design, engineering, analysis, and

management of complex Earth systems

ESEM takes a holistic view of multiple issues affecting

our Earth

Environmental, social and other considerations taken

into account up front in the design process

Adaptive systems approach: Ongoing analysis feeds

back into the continual management of the system

GIS and the emerging field of GeoDesign are critical

to the success of approaches such as ESEM and

other logical and rational models for dealing with the

environmental and planning problems of our and

future generations (Braden Allenby, "Biomass

Management Systems" in Reconstructing Earth,

2013)

Ethical practice of social studies moral imperative

GIS Green Solutions

Thank You

Celéste Dekker

[email protected]

(012) 310-2622

ARC-ISCW

GeoInformation Division

mailto:[email protected]

using gis in site suitability for aquaculture: green

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