Planning tools for environmentally sustainable tropical finfish cage culture in Indonesia and northern Australia

The project commenced in April 2005, with collaborative activities initiated with partner laboratories in Bali and South Sulawesi. In consultation with staff of the Gondol Research Insitute for Mariculture (GRIM), and the Research Institute for Coastal Aquaculture (RICA). sampling methodologies were agreed upon that could be applied to all study sites in order to ensure consistency of approach. The RICA team commenced regular sampling of study sites in Barru Regency, South Sulawesi, in July 2005, concentrating on water quality parameters and chemical composition of the sediments in the vicinity of an experimental sea cage array owned by RICA. Collaboration was also commenced with the Centre for Coral Reef Studies at Hasanuddin University, Makassar. Two postgraduate studies and a number of undergraduate studies were commenced in the same area as the RICA studies, with an emphasis on the productivity of primary producers that may be active in taking up waste nutrients from aquaculture. In August Dr. Halmar Halide, an ACIAR-funded Post-Doctoral fellow, commenced duties at AIMS to undertake the modelling components of the project. Dr Halide has a PhD in physics and is an Indonesian national, which has greatly aided with communication and in establishing linkages with Indonesian agencies. The first field trip to the Australian study site, the Marine Harvest farm at Port Hurd, Bathurst Island, occurred in September 2005. Two staff from RICA joined the AIMS team for this work prior to visiting partner laboratories and aquaculture facilities in Darwin, Cairns, Townsville and Sydney. Physical oceanographers from AIMS made a separate visit to the farm in November to conduct measurements of water movement within the Port Hurd estuary, and to collect the data necessary to provide accurate tidal predictions for the farm.

Results to hand from the regular monitoring of seacages in South Sulawesi, and from the single field trip to Port Hurd, indicate that the environmental effects of these farms appear to be quite small and very localised. Though the Marine Harvest farm is the only industrial-scale fish farm in SE-Asia, the high tidal energy and high natural assimilative capacity of the waters of Port Hurd appear to effectively dissipate wastes from the farm. Consequently, in November we visited potential study sites in Lampung, Indonesia, where aquaculture activity is far more developed and where there are potentially greater environmental effects.

The National Steering Committee for aquaculture planning, an essential extension mechanism for the outputs of this project, was launched in Jakarta on November 24, and the project formally launched in Makassar on November 25. Following these events, AIMS) and UNSW staff from the parallel land-based aquaculture project collaborated with RICA staff in a field trip to Barru, and met with project staff to share the data to hand and plan future activities.

Project activities during 2006 emphasised the collection of field data to support the development of models of aquaculture impacts with field trips to both Australian and Indonesian study sites - these are described in detail below. In May 2006 we visited the Balai Budidaya Laut laboratory in Lampung to arrange access to commercial scale sea cage sites in Lampung Bay. In addition, during this visit AIMS staff members conducted training activities for the staff of RICA, as well as selected participants from Hasanuddin University (UnHas), BBAP Takalar, Muslim University of Indonesia (UMI) and Poltek Petanian Pangkep Regency. A progress review of this project and its partner project FIS 2002/076 Land Capability Assessment and Classification for Sustainable Pond-Based, Aquaculture Systems occurred concurrently, and was attended by Mr Barney Smith, Dr Ketut Sugama (CRIA) and Dr Fatuchri Sukardi (DGA). Project liaison and co-ordination meetings were held in August and December 2006. In December 2006 Dr Sudirman, the Dean of Fisheries from Hasanuddin University, Makassar, visited AIMS for 2 weeks to complete a manuscript detailing the activities of wild fishes around sea cages - the first such account from the tropics. Wild fish are attracted to both the structure of sea cages and to wastes from the cages and constitute a significant sink for aquaculture effluents that is very poorly parameterised in the existing literature.

Field activities: Our goal is to be able to compare the environmental footprint of sea cage farms in the tropics, where there is a distinct dry and wet season. The Australian study site was the Marine Harvest barramundi farm in Port Hurd, NT. The Port Hurd site is a high energy environment - with an 8m tidal range and 2 knot tidal currents. In August 2005, during our dry season field trip, the farm was the only industrialised sea cage farm in SE Asia, and was holding 1300 tonnes of barramundi. Unfortunately the farm was severely damaged by bad weather in January 2006, and our wet season field trip in February 2006 found the farm holding ~100 tonnes of barramundi. The Port Hurd farm was subsequently decommissioned, and Marine Harvest applied to the NT government for licences to operate in other areas, but subsequently withdrew from their Australian operations at the end of 2006. Our studies indicate that the strong tidal currents are the primary mechanism of waste dissipation from the farm, with no detectable accumulation of wastes on the scoured sediments under the farm, and only an extremely localised farm effect in the water column itself.

In South Sulawesi, RICA has been undertaking fortnightly water and sediment sampling in the vicinity of seacages in Arawange and Labuange Bays, Barru Regency. This regular monitoring study is forming the backbone of the data we will use to estimate background levels of nutrients in a coastal zone with multiple uses, and to put the environmental effects of sea cage aquaculture in the context of other inputs. The Hasanuddin University component of the project, which involved field measurements of seagrasses, macroalgae and wild fishes has been completed successfully, and the data passed to AIMS. These data will be used to estimate environmental assimilative capacity.

In August - September 2006 AIMS undertook the first of two field trips to Indonesia to measure key ecosystem processes. These include studies of circulation and currents, respiration and production, nutrients, plankton, nitrogen turnover and fixation, denitrification, ammonification and sulphate reduction. Field studies commenced at BBL Lampung, and concentrated on a commercial grouper farm (Ayong) and also on the experimental cage site adjacent to the laboratory itself, in Hurun Bay. After 10 days the equipment was shipped to our study site at Arawange Bay in South Sulawesi, and the same measurements made there. This field work has involved a considerable logistic exercise in the importation and trans-shipment of a large amount of field gear and has been made possible by the excellent working relationship we enjoy with our Indonesian project partners. The gear has been left in South Sulawesi for our wet season field trip scheduled for March 2007.

Project activities during 2007 were aimed toward the completion of field studies in Indonesia and in the finalisation of aquaculture planning tools.

In March AIMS scientists undertook the second of 2 field trips to Indonesia to complete the wet season - dry season comparison, as well as complete work at our study sites in South Sulawesi. A project variation funded in March 2007 allowed us to expand studies to Lampung, where the fish farms are larger and we expected a more significant environmental impact. In May AIMS' physical oceanographers conducted studies of currents and circulation in Teluk Lampung, with particular attention to the area around Tanjung Putus, where there is a concentration of sea cages. The emerging picture from our studies in Indonesia is that in these microtidal environments there is little physical dispersal of aquaculture wastes, since the currents are very weak. Consequently, the main mechanisms by which aquaculture wastes are dissipated are by biological assimilation rather than physical dispersal. However, the footprint of the farms we have visited appears to be very small, with noticeable changes in benthic processes limited to sites within 100m of the cages, and little effect on water column processes at all.

In July 2007 the RICA team completed 2 years of water quality sampling in the vicinity of sea cages in Awarange and Labuange Bays, South Sulawesi. Water quality and the occurrence of toxic algal blooms has occasionally been problematic in these areas. These issues are important because of the location of RICA's new hatchery in Awarange Bay and because of the presence of commercial farms in Labuange Bay. RICA has also completed 4 field trips to the Tanjung Putus area of Lampung, towards the project goal of comparing the environmental effects of land-based and seacage aquaculture. In addition, RICA has produced an estimate of waste loading into Hurun Bay, Lampung, and completed a study of uptake of waste grouper feeds by wild fish communities at Awarange Bay.

In order to progress completion of the mapping products in May 2007 Gajah Madah University was engaged as a project partner for this project- they are already partners in the parallel land-based project FIS/2002/076 and will now take primary responsibility for mapping 4 focus areas in South Sulawesi to identify sites suitable for sea cage aquaculture, taking into account adjacent land-based aquaculture. This collaboration was facilitated by a workshop held at Sydney in Sept 2007, in which the site selection criteria were drafted and a strategy developed for delivering the map series needed for the coastal classification scheme.

In conjunction with FIS/2002/076, we have established a National Steering Committee for Aquaculture development in Indonesia, as well as a Local Advisory Committee in South Sulawesi. In November 2007 both projects participated in an LAC meeting in Makassar chaired by Dr Fachturi Sukadi. The meeting was part of an extension workshop to identify and address stakeholder needs to underpin the development of extension materials for 2008. The meeting was attended by 85 participants from South Sulawesi, including land- and sea-based farmers, Regency and Provincial managers, Dinas Perikanan and other stakeholders and interested parties.

A major project deliverable, the model to calculate carrying capacity (entitled CADS_TOOL) was finalised in the second half of 2007. CADS_TOOL was developed by Dr Halmar Halide, and is a Decision Support System which includes modules for site classification, site selection, 4 carrying capacity models, as well as an economic calculator. In November 2007 a workshop held in Lampung was jointly convened by ACIAR and NACA to compare carrying capacity models from the region and to identify information gaps and problems. The workshop involved participants from 7 Asian countries. The CADS-TOOL model was previewed at the workshop and subsequently adopted as the working model for aquaculture development in the region. CADS_TOOL has now been recoded in Java and is available on the AIMS web site.

Dr Halmar Halide, employed as a Post Doc with the project, completed his employment at AIMS in January 2008. During the period of this report, the project has won a John Allwright Fellowship for one team member (Muh Chaidir Undu), supported 5 collaborators in study tours in Australia, completed all field studies, and convened one international workshop.