Developing research capacity for management of Indonesia’s pelagic fisheries resources. ACIAR Project FIS/2009/059.
Indonesia’s pelagic fisheries resources are of considerable importance to the nation’s economy and as an important source of protein for Indonesia’s large population of 261 million people. Two species of critical importance to Indonesia and to neighbouring countries in the Indian and Western Pacific Ocean regions are yellowfin tuna (Thunnus albacares) and bigeye tuna (Thunnus obesus), and together accounted for around 6.3% of total value of Indonesia’s capture fisheries commodities in 2015 (MMAF 2016). Current assessments and management strategies are based on assumptions of single, separate Indian Ocean and Western Pacific Ocean stocks of both species. Understanding of connectivity of these species across the Indonesian archipelago and adjoining oceans was considered a high priority for improved management.
During the project development phase there was considerable concern about the rapidly increasing number of fish aggregating devices (FADs) in Indonesian waters, the associated impacts of increased fishing pressure on stocks of juvenile tunas, and likelihood of unsustainable fishing practices.
To improve Indonesia’s capacity to assess and manage its tuna fisheries by addressing key information gaps, particularly for yellowfin tuna (YFT) and bigeye tuna (BET), and to improve Indonesia’s pelagic fisheries research capacity. The immediate objectives of the project fell within three primary components: 1. defining the population structures of YFT and BET in Indonesia’s archipelagic waters and connectivity with adjoining regions; 2. assessing and characterising Indonesia’s FADs associated tuna fisheries, and 3. the communication of the project’s findings and recommendations to the Indonesian and international science and policy communities.
Population structure study methodologies:
Using three independent, complementary techniques – genetics (next generation sequencing and Single Nucleotide Polymorphism markers), otolith chemistry1 (analyses of stable isotopes and elements) and occurrence of parasites - to determine the degree of population structure and connectivity of YFT and BET between the central Indian Ocean, IAW and Western Pacific Ocean.
FAD fisheries study methodologies:
1. A review (as a bibliography compilation) of earlier FAD related studies in Indonesian waters; 2. An enumeration program at 4 key tuna landing locations (Padang, Palabuhanratu, Kendari and Sorong) to gather information on a wide range of aspects of the FADs and the FAD-based fisheries; 3. A preliminary survey of socio-/bio-economic aspects of FAD-based fisheries at Kendari and at Palabuhanratu; and 4. Trials of acoustic and visual census of assessing fish aggregations on and around FADs.
Population structure study outcomes:
The three techniques provided outcomes that were consistent with the inference of multiple populations for YFT and BET across the geographic range of the project. The outcomes of the genetics analyses suggested at least 2 or 3 genetic groupings for both species, with clines of genetic variation across the geographic range. The patterns of distribution of parasites suggested limited to no movement of fish (both species) westwards from the Indonesian archipelagic waters (IAW) into the eastern and central Indian Ocean, and also little movement from the Western Pacific Ocean westwards into the Indonesian archipelago. The overall outcome from the otolith chemistry analyses was that the YFT and BET had not moved large distances in their first 4 - 6 months of life. These results suggest that the current national and regional governance arrangements are likely to be consistent with the structure and connectivity of YFT and BET populations. The study achieved capacity development for Indonesian scientists in the analytical fields of three techniques, in addition to skills associated with the large-scale sampling program.
FAD fisheries study outcomes:
1. The literature review produced a bibliography of 116 FAD related research studies from Indonesian waters; 2. The enumeration program achieved 2,564 fishing trips surveyed for 3 vessel types (hand-line/troll-line, pole & line, and purse-seine) across the 4 focus locations and a total of 48,368 fish measured in the biological sampling program, and was sustained at two of the locations for 39 months; 3. The socio-/bio-economic study provided useful insights into the cost ‘dynamics’ of the FAD fishery operations, and capacity development in assessing the socio-economic aspects of the fisheries; and 4. The acoustic and visual census trials on FADs provided a foundation for further research on the behaviour of fish species following fishing events i.e. ‘recovery’ times around the Indonesian anchored FADs.
The population structure study, albeit a ‘first-look’ investigation involving only the juvenile life- history stages of the two species, has outcomes that will be a valuable contribution to current considerations by Indonesia and Regional Fisheries Management Organisations (including as inputs into the structure of regional stock assessments) on appropriate management for these globally significant resources. The study’s results will play a key role in defining future research activities to further investigate the degree of connectivity of the tuna populations in IAW and adjoining oceans, in particular the level of exchange with the WCPO. The capacity developments achieved in the project will ensure Indonesia’s fisheries scientists play key, prominent roles in the future research.
The FAD study was initiated in response to the need for targeted information on the deepwater tuna FADs and associated fishing operations, and, overall, its outcomes have met that need. The catch characterisations results have already assisted in gear selectivity analyses as part of Indonesia’s current Harvest Strategy (HS) development and confirmed that juveniles of both species comprise significant proportions of the catch of the gears (hand-line/troll-line in particular) fishing on Indonesian deepwater anchored FADs. This information has informed the HS process and will assist the technical development of management measures for improved sustainability of the fisheries. The capacity development achieved in the preliminary study assessing the socio-/bio-economic aspects of the fisheries will be directly relevant to minimising the impact of new management measures on the most vulnerable components of the fishery (i.e. the small-scale subsistence fishers).
This project demonstrated that the question of connectivity between IAW and adjacent oceans can be addressed through a combination of populations structure methods. Refining
and extending these result through multi-year sampling of spawning adults and or larvae and use of methods that provide more direct estimates of annual exchange between areas, such as close-kin Mark Recapture, should be a high priority for future work.
With increasing recognition of the importance of including socio-economic impacts on fishing communities (in particular impacts to small-scale fishers) in development of new management measures, the capacity development of Indonesian scientists in socio -/bio-economic assessment skills should continue and, if possible, be expanded.
Similarly, there is need for an ongoing capacity development2 for Indonesia’s fisheries scientists and relevant staff within the Directorates of MMAF in all aspects of developing and implementing harvest strategies, including operating models, Management Strategy Evaluation, and identifying realistic and practical management measures for the complex Indonesian fisheries.