An extremely precautionary management framework has been implemented in the fishery. For stock assessment purposes the fishery is divided into two key areas – the Arafura Sea and Gulf of Carpentaria. It is important to note that in setting catch limits for the fishery only estimates from the Arafura Sea assessment area have been used and therefore do not even consider the large resources available in the Gulf of Carpentaria area of the fishery. Actual available yields are therefore likely to be far greater however this approach provides very conservative catch limits for the fishery as a whole.
Stock assessments for the fishery were conducted in 1996 and 2004. The initial assessment used a stock reduction analysis model developed by Professor Carl Walters (Ramm 1997). The more recent assessment used yield per recruit and biomass dynamics models, which incorporated updated biological parameters (Blaber et al. 2005).
It has been agreed that a harvest level of 10% provides further precaution in the system. Current assessments provide sustainable yield estimates for the red snapper species group of between 2500t to greater than 5000t. The lower risk estimate of 2500t is currently the catch limit for the fishery while the biological parameters used in the assessments are refined.
Further securing the sustainability of the fishery are genetic studies showing some separation of saddle-tail snapper (L. malabaricus) stocks between Australia and Indonesia.
The Marine Environment
The fishery operates in an extremely clean manner with 80% of the catch being made up of the key red snapper target species. The precautionary management arrangements means we operate approximately two full time vessels in an area over 200,000 km2 (it would take hundreds of years to fish all of the fishery!!). Further operations are not permitted for more than 45 km from the coastline and large offshore areas are closed to trawl fishing as a further insurance against any negative impacts. Despite the fishery being assessed as having little if any impact on the marine environment Australia Bay Seafoods have instigated four key initiatives to further minimise the impacts of our operations.
Semi Demersal Trawl Nets
Fishing operations are conducted using a semi-pelagic demersal trawl. The trawl net was developed cooperatively by Australia Bay Seafoods and the government to minimise habitat disturbance whilst ensuring commercial catch rates were maintained. The quality of the retained catch was also improved by the reduction in the number of sponges and other unwanted species associated with the operations of traditional demersal trawls.
Different styles of aluminium grids are used in many prawn trawl fisheries to allow larger bycatch such as sharks to escape unharmed. Unfortunately these grids are simply unusable in trawling for fish as they would have to be would onto a net drum which simply cannot occur. To overcome this problem Australia Bay Seafoods have developed a large grid made from stainless steel wire rope which while successfully allowing larger bycatch to escape unharmed can also be wound onto the vessels net drum. A significant drop in shark catches has been seen since the grids implementation and again the quality of retained catch has improved.
Hopper release system
To assist in reducing release mortality, Australia Bay Seafoods has developed a system comprising grids and rails on the fish hopper to enable sharks and rays to be returned alive to the water via a chute with minimal handling. The hopper system is now being evaluated by other trawl fisheries interstate with the intention of incorporating its use as standard operating practice.
Square Mesh Net
This is used to allow small fish to escape.
As the Cod end fills with fish there is more tension on the meshes of the net, this tension reduces the size of normal netting and causes excess catch of unwanted small fish. To minimise the catch of small fish, Australia Bay seafoods utilise a square mesh (T90) Cod end extension. As the tension increases this section of netting stays open and allows small fish to escape.
The principal species landed in the Finfish Trawl Fishery are red snappers (Lutjanus malabaricus and L. erythropterus). Products from this fishery are marketed primarily as whole fresh fish, mostly on the Australian domestic market. The Northern Territory (NT) Fisheries Joint Authority (NTFJA), through the NT Fisheries Act 1988, manages all finfish taken in the fishery while the day-to-day management of the fishery is conducted by the Department of Resources (DoR). The management system is supported by strong legislation and implemented accordingly.
The fishery is managed under a strict quota system limiting catch of all species to very precautionary catch limits. In addition to these catch limits any fishing gear used in the fishery must be endorsed by the management agency. The management framework is further enhanced by the use of objectives, performance indicators, trigger points and defined management actions to ensure the fishery remains in its current healthy state.
The fishery is monitored primarily through logbooks, which the company are required to fill out on a daily basis during fishing operations. The logs provide detailed catch and effort information, as well as information on the spatial distribution of fishing activity within the fishery. The company also provides marketing information to the agency to further aid fishery assessment and compliance.
In addition to logbooks, DoR observers conduct on-board monitoring of commercial fishing trips. While on-board, observers document vessel and gear information, location, depth, fishing practices, catch composition (including bycatch), and where possible, measure most landed species. These independent observer trips allow for independent validation of Australia Bays Logbook information.
The fishery was assessed in 2009 by the then Australian Government’s Department of Environment, Water, Heritage and the Arts against the Guidelines for the Ecologically Sustainable Management of Fisheries. Full export exemption accreditation was subsequently issued under the Australian Government’s Environment Protection and Biodiversity Conservation Act 1999. The assessment demonstrated that the fishery was managed in a manner that does not lead to over-fishing and that fishing operations have minimal impact on the structure, productivity, function and biological diversity of the ecosystem. The fishery is scheduled for re-assessment in May 2014.