Self-thinning, biodeposit production, and organic matter input to the bottom in mussel suspension culture

Future mussel suspension-culture methods may increasingly bypass standard population density adjustment on culture gear. This likely to exacerbate mussel fall-off. The potential extent of mussel fall-off is unknown. Here I use Dynamic Energy Budget theory and self-thinning theory to model the contribution of mussel fall-off to the total input of organic matter to the bottom. I focus on mussel populations grown on collector ropes and undergoing space-regulated self-thinning. Over a complete growth cycle, fall-off of mussel biomass was three times as high as the quantity harvested and accounted for 59% of total input of organic matter to the bottom. Biomass fall-off with collectors was 6-30 fold higher than with sleeving methods, as estimated from the literature. The relative contribution of mussel fall-off increased in a step-like fashion with initial population density, indicating that either mussels or biodeposits may dominate the organic input to the bottom, unless year-to-year variability in spat abundance is very high. The relative contribution of mussel fall-off did not increase appreciably with the intensity of second-set, but total mussel fall-off did. Assessment of each input type to the bottom is required for forecasting the consequences of a shift in culture methods, as they have different, spatially structured, effects on benthic environments.     

Market driven management of climate change impacts in the Spanish mussel sector

Mussel farming is the largest aquaculture activity in Spain both in volume and value, being a key pillar for the development of the coastal areas in Galicia (NW Spain), where this production is concentrated. The available scientific knowledge suggests that in the long term the primary productivity of the Galician estuaries will be reduced due to climate change. Consequently, adaptive management will be required to face this challenge. The impact of the likely production decrease will depend, among other factors, on the availability of substitutes, being their identification the main object of this research. So, it was analysed whether this markets are integrated or not through cointegration tests, finding that only the French and the Spanish markets are partially integrated. This implies that since very little substitutes are available for the Galician fresh mussels, decreases in production will not necessarily affect producer's income, as prices increases will compensate the (eventual) reduction in volume. In terms of policy, this study suggests that market intelligence may contribute to an adaptive, pragmatic and flexible framework to face climate change impacts, avoiding too anticipated or blind responses that may result in economic, environmental and social costs.     

Political regulation and radical institutional change: The case of aquaculture in Norway

This study investigates the transformation of the political regulation of the Norwegian aquaculture industry. The study is conducted as a historical-institutional analysis of industrial development combined with analyses of the multiple impacts of directives produced by changes in international political institutions. We describe a transformation from a corporate regulation regime to a new regime based on control and monitoring. The origin of these changes is very much a result of the interplay between actors and organizations at separate but interconnected levels. Our empirical discussion is informed by the neoinstitutional organization theory.     

The management of the blue whiting fishery as complex social-ecological system: The Galician case

In Europe, 88% of fish stocks are being fished beyond Maximum Sustainable Yield and 30% of stocks are outside of biological limits. The blue whiting fishery is also following a consistent trend of a declining, and the EU recently adopted a 93% quota decrease for this species. Despite the abundant literature related to genetic aspects of population structure of aquatic resources, few studies have specifically addressed the link between fisheries management and population genetics. Given potential differences in the behavior of different subpopulations, population genetics has great relevance in the correct interpretation of the evolution of stocks. Ignoring the congruence of spatial scales between the population structure of fish species and management units can result in reduced productivity and local reduction of populations.     

The promise and perils of building a co-management regime: An institutional assessment of New Zealand fisheries management between 1999 and 2005

This article uses a longitudinal survey (1999–2005) of commercial stakeholder organizations (CSOs) to assess the development, strengths and weaknesses of New Zealand's fisheries co-management over its first six years. After presenting the current characteristics and activities of CSOs, the institutional analysis and development (IAD) Framework is used to examine the regime. Results show a pattern of strengths and weaknesses with some areas substantially improved since earlier waves of the survey, while other areas have experienced surprising setbacks. These results suggest that in 2005 the regime remained fragile. Finally, New Zealand's recent move towards inshore “Shared Fisheries” management is explored in light of these findings.     

Transferability of fishing rights: The Spanish case

Some authors defend the implementation of regulation mechanisms such as individual transferable quotas, that is, the capacity to assign every fisherman an individual right so that he can fish a certain quantity of a specific species during a concrete period of time, as the most efficient way to reach a greater resource assessment and to guarantee biological sustainability. Nevertheless, much attention has been brought to the fact that, since these rights can be sold, negotiated, exchanged or transferred by the owners, it can bring about a concentration process, which would not favour social equity.     

Searching for sustainability in aquaculture: An investigation into the economic prospects for an integrated salmon–mussel production system

The pollution effects of cage aquaculture represent an external cost to society, and the challenge for environmental economists has been to estimate the magnitude of these costs and to suggest ways in which they can be mitigated or ‘internalised’. One possible mitigation strategy involves the development of integrated production systems based on polyculture, and this paper examines the financial viability of such a system that integrates the farming of salmon and mussels. The results demonstrate the commercial potential of an integrated salmon–mussel production system under present market conditions, but highlight the critical role played by future price trends.     

深海半潜浮式生产平台关键理论与技术问题

深海半潜浮式生产平台FPU(floating production unit)是国际海洋油气资源开发的关键基础性装备。针对半潜浮式生产平台的技术特点,系统阐述其各方面特性(包括:总布置、系泊和立管、水动力性能、结构设计与分析等)及相关研究现状和未来发展趋势。并结合我国南海地理、水文和资源环境等特点,对未来半潜浮式生产平台的开发提出了一些建议。     

Institutional change,fishing rights and governance mechanisms: The dynamics of the Spanish 300 fleet on the Grand Sole fishing grounds

The “Spanish 300 Fleet” on the Grand Sole fishing grounds has been one of the most important fleets in Europe for decades. This paper analyses the process of institutional change that has determined the governance mechanisms and the property-rights system in the case of the Spanish 300 fleet. It studies the centralized top-to-bottom process of institutional change that has included some relevant legal norms such as the approval of the compatibility of the vessel scrapping grants while retaining ownership of the fishing rights, the transferability of rights and lastly the implementation of ITQs in 2007, among other changes. This evolution of the governance mechanisms has facilitated the modernization and size adjustment of this fleet, which has been oversized for the fishing opportunities provided by the TACs. The paper explains how this process of institutional change has implied a reduction of the “300 fleet” to a 100 fleet while shedding light on the relationships between institutional change, governance mechanisms and the property-rights system in this case of fisheries management.     

Economic incentives for sustainable hilsa fishing in Bangladesh: An analysis of the legal and institutional framework

Bangladesh's hilsa shad (Tenulosa ilisha) comprises the largest single-species fishery in the country, constituting 11 per cent of the total catch and employing 2.5 million people directly or indirectly. Since 2003, following a sharp decline in catch figures, the hilsa fish has been the subject of a government conservation programme offering fishers economic incentives or payments for ecosystem services (PES). While PES schemes are widely used to conserve natural resources such as forests and watersheds, Bangladesh's programme is a rare example of PES for sustainable fishery management. Catch figures have improved since the programme was introduced; but concerns remain about fishers’ socioeconomic conditions and the long-term sustainability of Bangladesh's hilsa fishery. This paper analyses the conservation scheme's legal and institutional frameworks, identifying challenges to its design and implementation, and makes recommendations to overcome them.     

青岛灵山湾筏式养殖魁蚶食物来源的季节变动研究

魁蚶（Anadara broughtonii）是我国北方重要的经济贝类,筏式养殖是其主要的生产方式。2014年5月至2015年1月,测定了不同季节灵山湾筏式养殖魁蚶及其3种潜在食物源（表层颗粒有机物SPOM、底层颗粒有机物BPOM和附着微藻AM）的碳氮稳定同位素（δ13C和δ15N）,结合胃含物分析研究了海区食物源结构的季节变化对魁蚶食物组成的影响。结果显示,魁蚶及其食物源的稳定同位素比值均存在明显的季节差异,魁蚶的δ13C值（-19.6‰~-19.2‰）介于SPOM （-23.3‰~-21.8‰）、BPOM （-22.1‰~-21.2‰）和AM（-17.0‰~-16.0‰）之间,δ15N值范围集中在8.7‰~9.9‰。冬季魁蚶的δ13C值最低,δ15N值则最富集。水体颗粒有机物（主要由浮游植物组成）是魁蚶的主要食物来源（60.0%~77.8%）,以夏季的饵料贡献率最高;海区再悬浮作用使BPOM的贡献率始终维持在较高水平（30.8%~47.1%）;而养殖网笼上的附着微藻也可为魁蚶提供约22.1%~40.0%的食物。研究揭示了筏式养殖魁蚶可以混合滤食颗粒有机物和附着微藻,附着微藻是其重要的食物补充。     

The institutional implications of environmental ethics for fishery management in the US exclusive economic zone

The public discourse surrounding many fishery management issues suggests that ethical concerns may be an important aspect of these issues for a segment of the American public. Questions have been raised about the capacity of regional fishery management councils created under the Fishery Conservation and Management Act to be adequately responsive to different ethical values. To date, legislative efforts to broaden council membership have been unsuccessful, but pressure for institutional reform is likely to increase with the adoption of an ecosystem approach to fishery management.     

气象条件对滨海旅游经济产出的弹性影响——以青岛为例

从计量经济学的角度,采用柯布-道格拉斯(Cobb-Douglas,C-D)生产函数模型,分析了不同气象变量对青岛地区滨海旅游的经济产出弹性影响。结果表明:滨海旅游经济产出与高温日数在1%水平下显著正相关,与降水日数、大雾日数、雷暴日数和大风日数均在1%水平下显著负相关;降水、雷暴、高温和大雾天气是影响经济产出的高敏感性因子,在每提高1%水平的情况下,其弹性影响分别达到-0.679%、-0.507%、0.311%和-0.288%;21世纪以来,青岛地区降水和雷暴天气呈减少的趋势,高温天气则呈增多的趋势,均有利于滨海旅游产值的增加。     

The effects of reflection coefficient of the harbour sidewall on the performance of floating breakwaters

This paper studies the interaction of linear water waves with a moored floating breakwater with a leeward boundary composed from a vertical wall. This describes a real modelling for the case of ports in contrary to the problems of unbounded domains. It involves the application of a partial reflection boundary condition for this sidewall. In fact, the partial reflection problem in practical application is of great importance in the design of a harbour or breakwater and mainly for short waves. The reflection coefficient of the harbour boundary (sidewall) plays an important role in modifying the performance of the floating breakwater. Moreover, it reduces the resonant peaks appearing inside the ports due to the energy accumulation in an enclosed domain. The effects of the variation of structural parameters of the breakwater on the transmitted wave height are discussed in details for various values of partial reflection.     

Patterns of fisheries institutional failure and success: Experience from the Southern Gulf of St. Lawrence snow crab fishery,in Nova Scotia,Canada

This paper examines why market and government institutions failed to prevent over fishing in the Southern Gulf snow crab fishery, whereas non-market institutions succeeded. A general conclusion is that the institutional environment in which economic behaviour must be coordinated for successful fisheries management is complex. More specifically, collective action dilemmas arise from the interdependency of human and fish species interactions. However, successful institutions are capable of resolving these dilemmas when they achieve credible commitment. Coordination mechanisms such as co-management contracts, horizontal patterns of communication and win–win negotiations all contribute to building an institutional arrangement in which participants are motivated to comply with conservation objectives.     

Focusing on artisanal fleets in a new scenario: The case of Andalusia (Spain)

This paper analyses how artisanal fleets in the South Atlantic Coast of Spain (Andalusia) are transformed at the macro-level by political and economic processes. The article will first describe the web of economic and political dynamics, and it will then outline several socioeconomic and cultural patterns of artisanal fleets, examining strategies that are used to encourage commercial specialisation, technological innovation, capitalisation and productive intensification. The resulting social conflict is also examined. From such a study, this essay intends to promote a theoretical debate concerning the importance of new conceptions of artisanal fishing today, a time when local and global processes are highly interconnected.     

The economic impact of aquaculture expansion: An input-output approach

While the expansion of aquaculture production can confer positive economic impacts, under certain conditions, aquaculture can also have negative environmental impacts. Understanding the total economic impacts of aquaculture expansion is therefore necessary in order to make informed decisions when weighing economic considerations against environmental concerns. This paper considers the wider economic impacts, both direct and indirect of expansion in the Irish aquaculture industry. By disaggregating the aquaculture sector from Ireland's 2010 Input-Output table and calculating the resultant Leontief inverse matrix a number of economic multipliers for the aquaculture sector are estimated and used to calculate the potential indirect impacts of expansion. These multipliers are then used to estimate the economic impacts of reaching the targets set out in the recently published Irish national strategic plan for sustainable aquaculture, highlighting the potential for such an expansion to contribute to the rural economy.     

东海细菌丰度和生产力的季节变化及与浮游植物生物量和生产力的关系

The East China Sea is a productive marginal sea with a wide continental shelf and plays an important role in absorbing atmospheric carbon dioxide and transferring terrigenous organic matter to the open ocean. To investigate the roles of heterotrophic bacteria in the biogeochemical dynamics in the East China Sea, bacterial biomasses(BB) and productions(BP) were measured in four cruises. The spatial distributions of the BB and the BP were highly season-dependent. Affected by the Changjiang River discharge, the BB and the BP were high in shelf waters(bottom depth not deeper than 50 m) and generally decreased offshore in August 2009. In December 2009 to January 2010, and November to December 2010, the BB and the BP were high in waters with medium bottom depth. The onshore-offshore decreasing trends of the BB and the BP also existed in May–June 2011, when the BB was significantly higher than in other cruises in shelf break waters(bottom depth deeper than 50 m but not deeper than 200 m). The results of generalized additive models(GAM) suggest that the BB increased with the temperature at a range of 8-20°C, increased with the chlorophyll concentration at a range of 0.02–3.00 mg/m3 and then declining, and decreased with the salinity from 28 to 35. The relationship between the temperature and the log-transformed bacterial specific growth rate(SGR) was linear. The estimated temperature coefficient(Q10) of the SGR was similar with that of the phytoplankton growth. The SGR also increased with the chlorophyll concentration. The ratio of the bacterial to phytoplankton production ranged from less than 0.01 to 0.40, being significantly higher in November–December 2010 than in May–June 2011. Calculated from the bacterial production and growth efficiency, the bacterial respiration consumed, on average, 59%, 72% and 23% of the primary production in August 2009, November–December 2010, and May–June 2011, respectively.