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Assessment of the potential to develop mariculture in Western Australia

D.P. Shepherd

Research Officer
Agriculture Western Australia
Baron-Hay Court, South Perth WA 6151
(08) 9368 3853, (08) 9368 3939 (of corresponding author)
dshepherd@agric.wa.gov.au

Abstract

Since 1998 the Spatial Resource Information Group at Agriculture Western Australia has used a comprehensive Geographic Information System (GIS) to identify potential coastal locations for land-based Abalone and Finfish aquaculture or Mariculture. These analyses have been used by Fisheries Western Australia and the fisheries industry in WA to investigate specific locations for development of these industries.

Potential locations for land-based Abalone production and Mariculture were assessed against series of environmental conditions suitable for the location of production facilities. These conditions were defined by scientists from Fisheries WA in consultation with staff from Agriculture WA. These conditions included maximum distances from the tidal low water mark, from infrastructure such as population centres, roads and the power grid, steepness of the coastline and soil types and water quality for specific sites.

Following the refinement of selection criteria for site suitability mapping in July 1998, GIS analysis was commenced at Agriculture WA.

The GIS analysis was carried-out in three steps.
- Collation and preparation of digital data for analysis.
- GIS analysis of relationships between land parcels and site selection features.
- Comparison with contour data/terrain models and coastline features of parcels identified through the previous step to identify suitable sites for production.

Areas identified through the GIS analysis as potentially suitable for Abalone production were verified in the field by a staff from Fisheries WA and an industry consultant in 1999.

The methodology, results and database developed during these analyses are now valuable resources for the assessment of potential for expansion of other fisheries industries in Western Australia. The use of GIS for this application has greatly improved the efficiency of a previously labour-intensive exercise, and should improve the level of resources available for on-ground site assessment and industry liaison.

Introduction

Previously knowledge on potential sites for the expansion of existing fisheries industries and the potential for new industries in Western Australia has been difficult or expensive to develop. To acquire suitable sites, aquaculture proponents have undertaken similar site identification, selection and application processes. This has resulted in substantial replications of effort and resources. In order to remove the need for future aquaculture proponents and applicants to repeat the basic survey work, Fisheries WA proposes to make the relevant information about coastal areas and selected locations more definitive and available (Makaira Pty Ltd 1999).

The first stage of this process involved the engagement by Fisheries WA of Agriculture WA to use a Geographic Information System (GIS) on a broad scale, using limited selection criteria, to conduct a site-suitability for mapping exercise of coastal areas of Western Australia between the South Australian border and Shark Bay for land-based Abalone production. This work is now complete and a final report has been produced (Shepherd, 1998).

In late 2000 Fisheries Western Australia approached Agriculture Western Australia to cinduct a similar exersise to identify potential sites for mariculture along the entire Western Australian coastline. This report describes the methodology used and results of this project.

Methods

Scope and criteria for mapping potential sites for mariculture

Potential sites were identified for mariculture in two regions: the Extensive Land-Use Zone (ELZ), which extends from the Zuytdorp Cliffs of Shark Bay north to Kunnunurra; and the Intensive land-Use Zone (ILZ), extending southwards and eastwards from Perth to the southern Western Australia border.

The main selection criteria used to identify the preliminary sites were: proximity to power and roads; distance from the low water line, distance from a river mouth and the nearest town; and site tenure. Details of elevation above mean sea level and site areas are also provided as indicators of site suitability but were not used in the GIS analysis. A table of criteria used to identify suitable sites in provided in Table 1.

Table 1. Themes used in GIS analysis for site suitability

Theme

Unit of measure

 

Selection Criteria

 
   

High

Medium

Low

Distance from Low Water Mark

Km

0 - 1

1 - 2

2 - 5

Distance from major population centre (>=2000)

Km

0 - 50

50 - 100

100 - 200

Distance from River Mouth

Km

>7

3 - 7

<3

Proximity to roads & power

(Sealed and Primary Unsealed / >33Kv)

Km

0 - 2

2 - 5

5 - 10

Other themes considered

Elevation (above mean sea level)

Metres

0 - 7

7 - 12

12 - 17

Area of potential site

Ha

>5

3 - 5

<3

Land tenure

 

Free-hold

Unallocated crown land

Reserves and parks

Freshwater availability

M3

10,000

50,000

<50,000

Site soil type

 

Clay

Sand

Rock

Data collation

The initial part of the project involved collation of the datasets described in Table 1. Existing data holdings at Agriculture WA included land tenure, infrastructure (roads and power), hydrology (major water courses and river mouths), the coastline, population centres and some height above sea level data. Additional height above mean sea level data were acquired from the Department of Land administration in the form of spot heights for some areas in the ELZ. At Agriculture WA GIS software was used to interpolate height contours at 7, 12 and 17 metres. For the ILZ existing contours at 5, 10 and 15 metres were used as a surrogate.

Additional data for local soils types and freshwater availability were supplied by officers from Fisheries Western Australia for some of the sites identified.

GIS analysis

The second stage of the project involved GIS analysis of some of the datasets collated in stage one. Buffers were generated around each theme according to the rules described in Table 1. These buffers were then intersected to identify potentially suitable sites. Initially distance from population centre buffers were intersected with distance from coastline buffers. The results of this intersection were then intersected with distance from infrastructure buffers. This result was then intersected with distance from river mouth buffers to create an interim dataset describing potentially suitable sites. Slivers and other processing artifacts were then removed from the interim dataset.

The third stage involved intersecting the result from stage 2 with tenure data. Only areas of high to medium suitability were intersected with the tenure dataset. The area of each cadastral parcel within areas of potential suitability were calculated. These can be used on close inspection of the dataset to determine areas of common tenure.

At this stage a series of ten maps were produced showing medium to highly suitable sites by tenure type (freehold, unallocated crown land and reserves). The ten maps cover all sites identified along the Western Australian coastline. These maps were passed onto Fisheries WA officers for comment.

From these maps and some field inspection Fisheries WA officers identified twelve sites of particular interest. Data on local soil types and freshwater availability collected by Fisheries WA for these sites were supplied to Agriculture WA for incorporation into the suitability dataset.

Results

Identification of sites of high, medium and low potential for mariculture

From the GIS analysis a total of 56 individual sites of high to medium were identified - 46 in the ILZ and 10 in the ELZ. Maps of these sites have been presented to Fisheries WA. A total of 2854 cadastral parcels occur within the areas of high suitability. Of these 13 percent are privately owned or leased, 3 percent are vested with commonwealth authorities and 3 percent are vested with state government agencies. Thirteen parcels are vested with local Authoroties. The remaining 80 percent of parcels are either vested with DOLA (coastal reserves) or are very small parcels in built-up areas.

A total of 37,334 cadastral parcels occur within the areas of medium suitability. Of these 9 percent are privately owned or leased, 9 percent are vested with commonwealth authorities and 2 percent are vested with state government agencies. One percent of the parcels are vested with local authorities. The remaining 88 percent of parcels are either vested with DOLA (coastal reserves) or are very small parcels in built-up areas. The area of each parcel potentially suitable for mariculture is available on the CD_ROM accompanying this report.

The medium to highly suitable sites identified are presented in Figure 1.

Figure 1. General location map for potential mariculture sites

Sites of particular interest

Twelve sites are been selected by Fisheries WA officers as being of particularly high suitability. These include sites identified having high or medium suitability from the GIS analysis. Local conditions not included in the GIS analysis make some sites originally identified as having medium suitability highly suitable. An example of a detailed site map for one of these sites is presented in Figure 2.

A potential Mariculture site information package for Fisheries WA

The datasets produced through this project as well as detailed report and tabular information on areas of interest were packaged onto a CD-Rom for Fisheries Western Australia. This CD-Rom product is now being used by Fisheries WA to investigate further the potential sites for commercial Mariculture identified in this project. Further investigation will involve on-ground assessments, liaison with industry, and negotiation with land-holders in potentially suitable areas.

Figure 2. Example of a detailed site map for potential mariculture sites

References

Makaira Pty Ltd, 1999. Land-based Abalone Farming – Site Suitability Assessment. Fisheries WA, Perth WA.

Shepherd, D.P., 1998. Land-based abalone mapping − GIS Site Suitability Mapping. Final Report on Site Suitability Mapping. Spatial Resource Information Group - Agriculture Western Australia, Perth WA. Unpublished Report to Fisheries Western Australia.

Shepherd, D.P., 2001. Indentification of potential sites for Mariculture using a Geographic Information system (GIS). Final Report on Site Suitability Mapping. Spatial Resource Information Group - Agriculture Western Australia, Perth WA. Unpublished Report to Fisheries Western Australia.

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