虾池环境生物修复作用菌的生产发酵与菌体收集工艺优化

为了实现所筛选的对虾养殖环境生物修复作用菌的产业化生产,本文选择三株具有高效降解有机污染物能力的菌株为代表,对作用菌的发酵生产和菌体收集工艺进行了优化。结果表明,作用菌的最适发酵培养基配方(g/L)为蛋白胨 25,酵母粉 5,磷酸铁 0.2,灭菌前培养基的 pH 可先调为 8.0,搅拌方式为搅拌1h 间隔 1h, 出罐时间以 20h 为宜。菌体收集以等电点沉降法效率最高、成本最低,其中菌株 Lt7222 的最适沉降 pH 为 3.67、Gy7018 为 4.02、Lt7511 为 3.40。菌体回收率可达 90 %,回收后菌体的存活能力几乎不受影响。     

Assessing prospects for shrimp culture in the Indian Sundarbans: A combined simulation modelling and choice experiment approach

India's Sundarbans region lies within the state of West Bengal and is part of the world's largest mangrove ecosystem. Low-intensity shrimp aquaculture is present, but the potential exists for more intensive development. We argue for avoiding environmental damage and social conflict by adopting appropriate policies now. In this study, we combine ecological simulations and a choice experiment to evaluate several policy scenarios. Such comparative evaluations combining different disciplinary tools are rare. While our ecological modelling supports severe restrictions on shrimp farming activities, local stakeholders prefer a more diverse strategy. Both models indicate that large-scale commercial shrimp aquaculture is least desirable.     

养殖用海管理问题与对策研究

我国是世界最大的养殖用海国家,养殖用海不但影响人民自身利益和社会的和谐稳定,并且也关系到沿海地区的经济发展。当前,我国养殖用海在自然资源统一管理和生态文明建设的新形势下存在规划繁杂重叠、环境污染、产权制度不完善等问题。文章将从养殖用海历年确权及注销面积和当前养殖用海管理现状出发,阐述我国当前养殖用海面临的问题,找出养殖用海空间保障不足的原因,并依据我国当前养殖用海管理所处的形势,提出了划定养殖用海基准线、编制“多规合一”下的养殖用海专项规划、施行养殖用海用途管制和整治修复、加强养殖用海监督管理等建议,解决当前养殖用海问题。     

Experiments on wave transmission coefficients of floating breakwaters

To find a simple, inexpensive, and effective type of floating breakwater for deep-sea aquaculture, we studied three types of structures: the single box, the double box, and the board net. We conducted two-dimensional physical model tests in a wave-current flume in the laboratory to measure the wave transmission coefficients of the three types of breakwaters under regular waves with or without currents. Based on the initial comparison of the wave transmission coefficients, we proposed the use of the board-net floating breakwater for use with fish cages; we then conducted detailed experiments to examine how wave transmission coefficients are affected by several factors, including the width of the board, the row number of the net, the rigidity of the board, and the current velocity. The experimental results show that the board-net floating breakwater, which is a simple and inexpensive type of structure, can effectively protect fish and fish cages and may be adopted for aquaculture engineering in deep-water regions.     

New Zealand seafood firm competitiveness in export markets: The role of the quota management system and aquaculture legislation

New Zealand's quota management system (QMS) was implemented in 1986 to address problems caused by a regulated open entry management system in place for the previous two decades. Excess capacity in the inshore fisheries caused several stocks to become depleted and conflicts to intensify between fishing sectors. The allocation of individual transferable quota (ITQ) was viewed as the best way to improve efficiency within the over-capitalised inshore fisheries and provide incentives for developing the deepwater fisheries. The expected benefits of the QMS fit with the political climate at that time, as the government was using market forces to address the deteriorating economy. This article outlines the results of a research project that involved four medium to large-sized, highly vertically integrated New Zealand seafood firms. The purpose of the project was to identify these firms’ sources of competitiveness in export markets and the process the firms used to develop sources of competitiveness, while adapting to rapid and radical changes to the political and business environment and transformation of the fisheries management system. The project's results show that the basis to seafood firm competitiveness is the security of supply to the fisheries resource provided by the QMS and aquaculture legislation. The project also outlines the role that government policies have in sustaining firm- and industry-level competitiveness. This article contributes to the broader discussion on the application of ITQ and other types of long-term access rights to the management of fisheries and does not express the views of the Ministry of Fisheries.     

Variability of the partial pressure of CO2 on a daily-to-seasonal time scale in a shallow coastal system affected by intensive aquaculture activities (Bay of Cadiz, SW Iberian Peninsula)

The present study describes the temporal variability of the water fCO₂ as well as the different driving forces controlling this variability, on time scales from daily to seasonal, in the Rio San Pedro, a tidal creek located in a salt marsh area in the Bay of Cadiz (SW Iberian Peninsula). This shallow tidal creek system is affected by effluents of organic matter and nutrients from the surrounding marine fish farms. Continuous pCO₂, salinity and temperature were recorded for four periods of approximately one month, between February and September in 2004.Major processes controlling the CO₂ variability are related to three different time scales. Daily variations in fCO₂ are controlled by tidal advection and mixing of the water from within the creek and the seawater that enters from the Bay of Cadiz. Significant cyclical variations of the fCO₂ have been observed with the maximum values occurring at low tide. On a fortnightly time scale, the amplitude of the daily variability of fCO₂ is modulated by the variations in the residence time of the water within the creek, which are related to the spring–neap tide sequence.On a third time scale, high seasonal variability is observed for the temperature, salinity and fCO₂. Maximum and minimum values for fCO₂ were 380 µatm and 3760 µatm for February and July respectively. Data suggest that seasonal variability is related to the seasonal variability in discharges from the fish farm and to the increase with temperature of organic matter respiratory processes in the tidal creek. The fCO₂ values observed are in the same range as several highly polluted European estuaries or waters surrounding mangrove forests. From the air–water CO₂ flux computed, it can be concluded that the Rio San Pedro acts as a source of CO₂ to the atmosphere throughout the year, with the summer accounting for the higher average monthly flux.     

Deterring effects of 8-45 kHz tone pulses on harbour seals (Phoca vitulina) in a large pool

The marine aquaculture industry suffers losses due to pinniped attacks which damage net enclosures and fish stocks. Acoustic harassment devices (AHDs) emit loud sounds which are intended to deter pinnipeds from approaching aquaculture enclosures. At present, many AHDs emit sounds in the 8-20 kHz frequency range. It is not known whether sounds of higher frequencies have a deterrent effect on seals. Therefore five captive harbour seals (Phoca vitulina) were subjected to four series of tone pulses together spanning a broad frequency range (8, 16, 32 and 45 kHz). Pulse duration was 250 ms and pulse interval was 5s. Each of the four sounds was made deterrent by increasing the amplitude. The seals reacted by swimming away from the sounds. The displacement effect of each sound was judged by comparing the animals' surface positions, and number of surfacings, during ten 45 min baseline periods with ten 45 min test periods per frequency (one frequency per day in rotation, 40 sessions in total). The seals were displaced by all four frequencies throughout the 40 trial days. The seals came to the surface more often when the test tones were produced than in the baseline periods. The initial displacement distances did not change over the 40 test days. This suggests that operating AHDs for only short periods will be more effective and less likely to result in habituation by the seals than operating them continuously. The discomfort threshold sound pressure level (SPL) was established for each of the four pulse frequencies. The acoustic discomfort threshold SPL is defined as the boundary SPL between the area that the animals generally occupied during the transmission of the sounds and the area that they generally did not enter during sound transmission. The discomfort threshold SPL may depend on the context.     

湛江红树林湿地沉积物有机碳分布特征及影响因素

红树林生态系统位于海洋与陆地的交界处,具有重要的生态服务功能。红树林湿地是重要的碳库,对全球碳平衡有重要影响。然而,由于受到人口增长、社会经济发展和城市化进程加快等人类活动和全球气候变化的影响,红树林正在加速消失。文章以广东湛江市国家级红树林自然保护区为研究区,通过分析红树林沉积物中的有机碳含量及分布特征,讨论人类活动(如,人工养殖)在湿地碳循环中的影响。本研究在研究区内获取15个样品,利用重铬酸钾氧化—还原容量法测定了沉积物中有机碳含量。结果表明:研究区内沉积物有机碳(TOC)含量介于0.68%～2.50%,同时TOC含量与研究区内人工养殖场排污口的距离有密切关系:离排污口越近,TOC值越低;离排污口越远,TOC值越高。此外,研究区内红树林TOC含量与其他红树林湿地TOC含量相比明显偏低,可能与养殖排污抑制红树林的生长和繁殖,从而使其TOC含量明显减少有关。     

Implementation barriers to establishing a sustainable coastal aquaculture sector

For much of the last century, the prerequisites for establishing a new primary industry were property rights to secure access to the required natural resources, the appropriate technology, brood stock and labour, and a willing investor. In contrast, in many western nations although all these prerequisites have been in place for the establishment of new coastal marine farming sectors, fledgling aquaculture operations have failed to establish. A prime reason for this is that under increasingly consultative integrated coastal zone management regimes, local stakeholders are expressing a desire for prospective aquaculture operations to demonstrate that they will be sustainable. Many potential marine farmers and regulatory authorities have stumbled on this demand and the work presented here aims to elucidate the nature of sustainability in a coastal aquaculture context and provide a framework for investigating these critical ‘non-traditional’ factors limiting the establishment and development of coastal aquaculture activities.     

Occupational health and safety hazards in Atlantic Canadian aquaculture: Laying the groundwork for prevention

The growing aquaculture industry is projected to feature ever more prominently in the lives and economies of rural coastal communities in Atlantic Canada and around the world. Both private industry and government have a responsibility to ensure employment opportunities created in aquaculture take place in healthy, safe environments. However, systematic occupational health and safety (OHS) research within this industry, an important prevention tool, is still in its infancy. With particular emphasis on marine aquaculture in Atlantic Canada, we provide a detailed outline of the structure of the industry from feed production through to processing, identify potential OHS hazards associated with each of these activities and make recommendations for future research and action.