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.

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Understanding the relationship between habitat and fish distribution is a central component in the recent shift towards ecosystem based fisheries management (EBFM). Determining the habitat requirements of commercially and ecologically important species will be essential if spatial management strategies such as marine protected areas (MP As) are to be used successfully to conserve marine resources. A review of demersal fish habitat research highlighted numerous areas lacking in this field of habitat science. These included the propensity for studies to focus on abiotic habitat variables such as depth and sediment over large spatial scales (≥ 100s km²) and the low number of studies analysing biotic habitat variables in general. I conclude that development of sound predictive science in this field is reliant on a change in research focus toward reductions in study scale, or increases in resolution for abiotic habitat variables and more integration of biotic variables into studies. The three field studies included in this thesis analyse the importance of prey resource for the distribution of demersal fishes over spatial scales ranging from hundreds of metres to tens of kilometres. The first study investigates the relationship between prey and predator abundance and prey size and predator mouth gape size for nine demersal fish species around the Balearic Islands in the Mediterranean. The results demonstrate that prey abundance and size are of significance for some demersal fish species feeding primarily on benthos and will help in defining habitat requirements of demersal fish species. Demersal fish feeding ecology is studied in more depth when I investigate the effects of a bottom trawl fishery on an invertebrate benthic community and the subsequent effects this has on two commercially important flatfishes (P. platessa and L. limanda). This chapter closes the gap between the effects of bottom fishing on benthic communities and the reduced condition of some fishes found within these areas. The results of this study suggest that alterations in prey abundances, sizes and availabilities caused by chronic bottom trawling may lead to reduced feeding efficiencies, particularly for species with narrow prey spectrums. This in turn could result in reduced conditions of affected fishes living in chronically disturbed areas. The final data chapter uses detailed habitat maps, based on differences in sediment characteristics between three sites to take a small spatial scale, high resolution approach to describing demersal fish habitat. This investigates changes in the feeding ecology of a demersal fish species, Callionymus lyra, with body length. Although significant differences in prey size and prey taxa selectivity were found, no significant relationships between prey resource and predator distribution were apparent for any of the year classes analysed. The potential ecological and methodological reasons for these findings are discussed in-depth. Finally, a general discussion examines the main findings and suggests areas for future development.

This thesis uses data collected between 2007 and 2010 in an intensive, effort-based visual monitoring survey in southwest Cornwall, UK. The survey was carried out from a strategic watchpoint overlooking a regionally unique seabed feature, the Runnelstone Reef, which has previously been identified as key site for all three of the study’s target species: harbour porpoise Phocoena phocoena, basking shark Cetorhinus maximus and Balearic shearwater Puffinus mauretanicus. The location of the survey site is perceived as a productive, coastal marine ‘hotspot’ by local wildlife observers, eco-tour companies, conservation bodies and commercial fishermen. The aim of the study was to use a multidisciplinary approach to investigate the drivers behind the increased abundance and diversity of mega-vertebrates at the site. A wide range of environmental data, from fine-scale bathymetry to remote-sensed oceanographic data, were utilised in an attempt understand the potential interactions between the target species and the environment at a variety of scales. Although the target species have very different ecologies and each represent a different taxonomic Class; they each face significant threats throughout their range due to human impacts and are all listed as species of conservation concern on a number of UK, European and International Directives and Conventions. Therefore, improving our understanding of their distribution and highlighting interactions between the animals and their environment is an important objective, both for science and conservation. Harbour porpoise sightings showed significant fine scale temporal clustering associated with tidal flow, as well as spatial clustering around parts of the survey area with steepest seafloor slopes. The timing and location of highest porpoise densities coincided with tidal-topographically controlled hydrodynamic features identified using fine-scale current profile data (ADCP). The sightings and acoustic monitoring (C-POD) data both showed a high amount of temporal variability at seasonal, daily and hourly scales, highlighting the complex nature of the fine scale animal-environment interactions. Daily patterns in basking shark sightings data were investigated as a function of physical environmental covariates, with particular focus on the effect of meso-scale thermal fronts. In line with previous national scale studies of the species, shark sightings were significantly affected by sea surface temperature (SST) and there was evidence for a change in seasonal abundance compared to the long-term pattern. In addition, the variance of SST over the preceding weeks was identified as being a key predictor of the abundance of sharks in the survey area. Surprisingly, there was not a significant effect of the presence, persistence or thermal gradient strength of fronts on daily shark sightings. The implications of this result are discussed with reference to results of previous studies and the focus of marine protected area policy in the UK. The broad scale spatio-temporal analyses of Balearic shearwater sightings data from the UK, Ireland and France indicate that the birds continue to be recorded in significant numbers throughout areas previously considered to be at the northernmost extent of their range. Record counts of passing birds were recorded off southwest UK in the last two years, along with unprecedented aggregations in bays along the Brittany coast, comprising approximately 20 % of the estimated global population. The data presented provide much-needed quantitative information on the at-sea distribution and behaviour of this Critically Endangered species during the interbreeding period, and support earlier studies suggesting a northwards shift in their migratory distribution.

This thesis explores some important practical considerations concerning the use of species distribution models in marine conservation planning. Using geo-referenced gorgonian distribution data, together with explanatory environmental variables, predictive models have been used to map the spatial distribution of suitable gorgonian (sea fan) habitat in two study sites; Hatton Bank, in the Northeast Atlantic, and Lyme Bay on the south coast of Devon. Generalized Linear Models (GLMs), Generalized Additive Models (GAMs) and a Maximum Entropy (Maxent) model have been used to support critical investigation into important model considerations that have received inadequate attention in the marine environment. The influence of environmental data resolution on model performance has been explored with specific reference to available datasets in the nearshore and offshore environments. The transferability of deep-sea models has been similarly appraised, with recommendations as to the appropriate use of transferred models. Investigating these practical issues will allow managers to make informed decisions with respect to the best and most appropriate use of existing data. This study has also used novel approaches and investigated their suitability for marine conservation planning, including the use of model classification error in the spatial prioritisation of monitoring sites, and the adaptation of an existing presence-only modelling method to include absence data. Together, these studies contribute both practical recommendations for marine conservation planning and novel applications within the wider species distribution modelling discipline, and consider the implications of these developments for managers, to ensure the ongoing improvement and development of models to support conservation planning.

The marine environment provides essential ecosystem services that are critical to the functioning of the earth’s life support system and the maintenance of human well-being. Marine Protected Areas (MPAs) are recognised as being the mechanism though which marine natural capital may be conserved. This thesis focuses on the value associated with marine conservation in a case study area, Lyme Bay, England where a ‘closed area’ was created in 2008. A review of literature spanning 20 years shows that despite sound ecological knowledge of a marine area, the reliance on traditional neo-classical economic valuations for marine spatial planning can obscure other issues pertinent to the ecosystem approach. A further valuation of the marine leisure and recreation industry shows that the industry is of economic significance and that the MPA enables the protection of the most valuable sites but has limited benefits for protecting the full resource base. In terms of ecological value, a ‘service orientated framework’ was developed to enable decision makers to understand the links between benthic species, ecological function and indirect ecosystem services. Results spatially identify which ecosystem services occur and demonstrate the value of the MPA in ensuring delivery of these ecosystem services. In relation to the social value of the MPA the research reveals that support for the MPA is strong amongst the majority of stakeholder groups. Values are expressed as the economic, environmental and social benefits of the MPA. However, there have been clear social costs of the MPA policy and these have been borne by mobile and static gear fishermen and charter boat operators. Each valuation methodology can inform decision making. Though, if ecosystem service valuation is to become a deliberative tool for marine conservation and planning, then there is a need for a larger societal discussion on what activities and trade-offs society considers acceptable.