Multidisciplinary appraisal of the effectiveness of customary marine tenure for coral reef finfish fisheries management in Nggela (Solomon Islands)

Abstract

The failure of centralised fisheries management systems to prevent the overexploitation of coral reef resources has led many scholars and conservation practitioners to promote the use of customary marine tenure (CMT) as an alternative devolved means of fisheries management. The effectiveness of CMT for fisheries management is debated; some scholars argue that CMT is embedded within particular historical, socio-economic and political contexts and that unless it evolves to changing circumstances, its effectiveness for fisheries management will wane under external influences and changing exploitation patterns. Each CMT regime is unique; hence its response to changing circumstances may vary. A better understanding of the circumstances under which a CMT regime is likely to succeed is important if it is to be effectively used for fisheries management. This research is posited on the DPSIR (Driver, Pressure, State, Impact, Response) model and employs multidisciplinary methods to investigate the effectiveness of CMT for reef finfish fisheries management. The aims of this thesis are: (1) To investigate the role of markets and subsistence as driving factors for fishing; (2) To investigate fisher spatial allocation of fishing, methods and target taxa (as proxies for pressure and impact); (3) contribute to the biological knowledge of a prominent vulnerable species (Plectropomus leopardus) by investigating aspects of its demography and reproduction (as a proxy for state); and (4) Investigate relationships between the Nggela CMT governance system and modern governance system (as a proxy for response), to improve understanding of how this knowledge may be applied to enhance small-scale fisheries management. The role of markets and subsistence as driving (D) factors for fishing was investigated using the sustainable livelihoods approach (SLA). Ninety three (43 from the western zone and 50 from the eastern zone) household surveys were conducted in 10 (5 from the eastern zone and 5 from the western zone) randomly selected villages in Nggela to determine the contribution of different livelihood activities to fisher livelihoods. The reason for comparing the eastern and western zone was to determine the role of available natural land capital as one contributing factor (besides markets) to fishing drivers. Quantitative data generated from the household surveys were analysed using the statistical package SPSS. Additional key informant interviews to generate qualitative data to support the quantitative data were also conducted. Spatial allocation of fishing and target taxa was investigated using household surveys (the same household survey mentioned above but with questions to address the issue of spatial allocation and fishing methods used), participative fishing with fishers to confirm spatial allocation of fishing and fishing methods employed and recording of landings data to determine the types of fish taxa targeted. One of the initial aims of studies on P. leopardus was to compare the age-based demographic parameters of P. leopardus between CMT areas and offshore sub-tidal areas, the hypothesis being that if CMT was effective agebased demographic parameters would reveal the non vulnerability of P. leopardus in CMT areas. Such a comparison was not possible as only 4 specimens were obtained from inshore CMT areas compared to 116 specimens from offshore sub-tidal reefs. To determine the age-based demographic parameters of Plectropomus leopardus, fish total lengths (mm) and otoliths of fish were collected in the field, this was followed by otolith annuli counts of ages (tagged to a particular fish of certain total length) at the laboratory. A von Bertalanffy growth curve was then fitted to the fish total length data and to the age data to determine asymptotic length, Brody growth coefficient and theoretical age at length zero. Total mortality rate was determined by generating catch curves where the frequency of fish in each age class was regressed against age. Longevity was determined by calculating the mean age of 10% of the oldest individuals. Demographic parameters of P. leopardus in Nggela were also compared to those of Australian locations to determine variations in age-based demography. Data analysis of P. leopardus data was done using the statistical software R and Microsoft Excel 2003. Reproductive aspects of P. leopardus were determined from the fish gonads collected from the field. Fish gonads were used to determine different sexual reproductive stages. Data on the different sexual reproductive stages was used to determine sexual maturity and sex change. The relationship between CMT governance and modern governance and how they may be combined for an effective reef finfish fisheries management was investigated using literature research, key informant interviews and dynamite fisher interviews. Investigations of livelihoods show that Nggela fishers were engaged in more than one livelihood activity for their livelihoods. Subsistence gardening was the most important livelihood activity. While finfish was important for subsistence purposes, accessible markets and the role of middlemen in the villages made it especially important for income generation. A comparison of the role of fishing between eastern and western zone showed that available natural land capital was also an important driver for fishing; fishing was higher in the western zone where there was a narrow natural land capital. Fisher perceptions indicate a declining trend in fisheries resource abundances within CMT areas; such decline has resulted in changes in the spatial allocation of fishing with a shift in fishing to offshore sub tidal reefs. Although some spatial closures were observed, fishing within the CMT areas is flexible. Three MPA’s currently existed in West Nggela and fishing prohibitions within the areas were observed mainly because people thought that the MPA’s were underscored by the government. Line fishing from dugout canoes remains the main method of fishing. Median trophic level of fish catch was between 2 - 3.84 while median standard length of catch was between 19 - 24 cm. Age-based demographic studies show that the Brody growth coefficient of Nggela P. leopardus was 0.13 yr-1, longevity was 12.9 years, maximum age was 15 years and mortality rate was 0.22% yr-1. Female sexual maturity of Nggela P. leopardus began at 2 years of age with 50% sexual maturity achieved at 3.22 years. Sexual transition from female to male began at 3 - 10 years of age with 50% sex change achieved at 11 years. Mature female to male ratio was 3:1. The age-based demographic parameters of P. leopardus in Nggela were similar to those in Swain and Lizard Island in Australia. For Swain reef, growth coefficient was 0.17 yr-1, longevity was 10.1 years, maximum age was 14 years and mortality rate was 0.39% yr-1. For Lizard Island, growth coefficient was 0.26 yr-1, longevity was 7.2 years, maximum age was 10 years and mortality rate was 0.59% yr-1. Age-based demographic parameters of P. leopardus in Nggela were different to locations in Western Australia – Scott and Abrolhos reefs. For Scott reef, growth coefficient was 0.42 yr-1, longevity was 6.4 years, mortality rate was 0.30% yr-1 while the maximum age was 8 years. For Abrohlos reef growth coefficient was 0.08 yr-1, longevity was 13 years, mortality rate was 0.24% yr-1 and maximum age was 18 years. Sea temperature may be one contributing factor to regional variations in age-based demographic parameters. The current CMT governance system has undergone changes which has rendered it ineffective as a coercive force for reef finfish fisheries management. While CMT is recognised by the modern governance system through National legislations, necessary ordinances at the provincial level are absent which prevent the effective use of CMT for fisheries management. For CMT to be effective it requires empowerment at the provincial government level. Positioning the above results within the DPSIR model, markets and narrow natural land capital are important drivers within the Nggela finfish fisheries. The main pressure within the Nggela finfish fisheries are increase in population growth and use of improved fishing technology some of which are destructive, this has resulted in the demise of the state of finfish fisheries (as revealed by fisher perceptions and low catch of P. leopardus in inshore areas), hence a shift in pressure to offshore sub tidal reefs. CMT as a policy response system is currently unable to effectively manage reef finfish fisheries; it needs to be empowered by the modern governance system to be effective for reef finfish fisheries management. Knowing how best to manage fisheries in an effective and sustainable way remains arguably equivocal around the world. Contemporary debates on fisheries governance increasingly highlights the importance of examining drivers of marine resource users’ behaviour and policy responses, as these information are considered essential for developing management goals that are more likely supported by those targeted. The research presented herein makes an original contribution to current thinking on the governance and management of coral reef finfish fisheries in locations where CMT is practiced.