Hydrographic conditions affecting two fishing grounds of Mallorca island (Western Mediterranean): during the IDEA Project (2003–2004)

This paper describes the hydrographic conditions observed during six surveys carried out during 2003 and 2004, in the framework of the “IDEA Project” (acronym for “Influence of oceanographic structure and dynamics on demersal populations in waters of the Balearic Islands”). The surveys were developed on the shelf and slope of Mallorca Island, in particular in two fishing grounds at the north and south of the Mallorca channel. Periodic movements of the fishing fleet between these two areas have been regularly reported, suggesting a seasonal variability of the resources which could be in turn associated with the hydrodynamic variability. With this motivation, water masses affecting these grounds have been identified and their seasonal variability has been studied. Different oceanographic and environmental conditions have been found between the two fishing grounds. These differences are related to the presence of mesoscale structures, associated with the Western Mediterranean Intermediate Water (WIW) at the north of the Ibiza channel and big gyres detached from the Algerian Current. The former has been shown to have influence on the regional oceanic circulation and the latter could affect the progress of fresh Atlantic Water (AW) towards the channels and make possible the presence of high salinity values at intermediate waters at the south of Mallorca Island. Historical data from other oceanographic cruises carried out in the region are finally used to discuss the interannual variability of these mesoscale structures.     

Relationship between condition and recruitment success of red shrimp (Aristeus antennatus) in the Balearic Sea (Northwestern Mediterranean)

This study evaluates the reproductive potential and condition of the red shrimp (Aristeus antennatus) population inhabiting the waters around the Balearic Islands (Northwestern Mediterranean Sea), between 1991 and 2004. Red shrimp is one of the most valuable exploited demersal fishery resources in the western Mediterranean. To assess the condition of this species, we use two indices based on weight and length data, one including the gonad weight and another excluding it. Different biological parameters of the population dynamics and reproductive biology, such as sex-ratio, maturity, gonadosomatic index and presence of the spermatophore in females have also been analysed. A negative relationship was found between the gonadosomatic index and the condition of red shrimp, indicating that energy reserves are transferred from the body to the gonad during the reproductive period. The condition of adults reached minimum values during the maturation and spawning period after mating, when the gonadosomatic index, the spermatophore presence in females and the proportion of females in the population were highest. The relationship between the condition of adults during the months prior to spawning and the number of recruits in the following year was significant and positive. This relationship was stronger when only male condition was considered, suggesting that males have an important role on the reproductive potential of this species. Overall, our results suggest that condition of red shrimp, particularly males, is an important aspect for the reproductive and recruitment success of this species. The observed decreasing trend in male condition over years may raise concern on the future reproductive potential of that population.     

Population dynamics of the red shrimp Aristeus antennatus in the Balearic Islands (western Mediterranean): Short spatio-temporal differences and influence of environmental factors

The red shrimp Aristeus antennatus is one of the target species of the bottom trawl fishery of the Balearic Islands. The objective of the present paper is to study the short spatial and temporal differences of this important economic resource between two different locations off Mallorca (Cabrera: CA; Sóller: SO), where a fleet mobility pattern has been detected, and to study the influence of environmental conditions on this species. Six simultaneous bottom-trawl and oceanographic surveys were carried out at these two locations in order to collect data from the demersal species, hydrography (temperature and salinity), trophic resources and sediment characteristics. The commercial fleet from both locations was monitored by monthly on-board sampling, log-books and daily landings obtained from sales slips. Additional data was obtained from other fishing surveys. Short spatial and temporal differences have been detected between both locations. The population at CA was more demographically homogeneous, while that at SO showed important variations, like high abundance of juveniles recruiting to fishing grounds in autumn–winter and high abundance of large females during summer. Several differences have also been found in the biology of the species between locations, such as males were more abundant in SO than in CA. Also, the reproductive period started sooner in SO than in CA, and the condition of pre-spawning females was better in SO. The percentage of total lipids in the hepatopancreas was minimal during the spawning period, showing their importance as a reserve of energy for the ovary ripening. Water masses could play an important role in these differences, the characteristics of water masses being more stable in CA than in SO. Red shrimp adult females seemed to be more correlated with the warmer and more saline Levantine Intermediate Waters, while juveniles (males and females) and adult males were more correlated with the colder Western Mediterranean Deep Waters, detected only in SO during autumn–winter. Two different hypothesis of mobility patterns for the species are discussed in relation to these observed differences.     

A Participatory Approach to Marine Habitat Mapping in the Grenadine Islands

Increasing interest in implementing an ecosystem-based management approach has made stakeholder involvement vital and has highlighted the need for an effective participatory framework. In this study we used a participatory geographic information systems (PGIS) framework to collaboratively map the marine resources of the transboundary Grenadine Islands with a broad range of stakeholders from the two sovereign nations. We found the application of PGIS allowed the collective resolution of an appropriate mapping scale and a locally relevant habitat classification scheme that would not only serve the needs of resource managers, but could also be understood by resource users. Furthermore, multi-level stakeholder involvement in the mapping process captured resource use profiles and other fishing-related attributes, gave credibility to local knowledge and ownership of information, and was instrumental in building capacity to access and use the produced information. Lessons learned included the importance of investing considerable time early in the participatory process, which was later rewarded by stakeholder buy-in and led to financial and in-kind support. Furthermore, hosting the information in multiple formats on a project website has resulted in easy access and use by a wide range of stakeholders over a cross-country scale. We believe our experiences will be valuable to other practitioners considering using PGIS, particularly for those working in similar resource-limited, developing nation contexts.     

21世纪地缘政治中的南沙群岛

随着南沙群岛油气资源的发现和开发,南沙群岛的价值和意义增加了,其战略价值也更加突出.本文认为,随着中国的发展和南沙群岛本身所拥有的资源及其战略地位的提升,人们在新的世纪里需要关注南沙群岛的动态和发展,及时制定和采取相应的应对措施,为我国的发展和外交创造良好的战略和安全环境.从地缘政治的视角看,南沙群岛对我国的战略意义至少表现在两个方面：第一,领土主权安全的标志和石油运输的战略通道;第二,油气资源的战略储库.     

Do Marine Protected Areas Affect Human Nutrition and Health? A Comparison between Villages in Roviana,Solomon Islands

The implementation of marine protected areas (MPAs) for fisheries management has increased recently due to the perceived role of MPAs in conserving biodiversity, increasing fish stocks, and enhancing the food security of coastal communities. However, it is unclear whether MPAs may restrict the availability of marine resources and decrease overall food security and the health of the people. In the Roviana Lagoon of the Solomon Islands, we conducted cross-comparisons of villages with MPAs and a village without an MPA to assess whether MPAs influenced local perceptions of governance, environmental change, livelihood strategies, and actual human nutrition and health. Results showed that residents of villages with effective MPAs had higher energy and protein intake than those who had no MPA or an ineffective MPA. We conclude that “no-take” marine reserves do not have adverse effects and that when MPAs are effectively sustained they may enhance local nutrition and health.     

The influence of oceanographic scenarios on the population dynamics of demersal resources in the western Mediterranean: Hypothesis for hake and red shrimp off Balearic Islands

The aim of the present paper is to study the relationships between some climatic indices and parental stock, recruitment and accessibility to trawl fishery of hake (Merluccius merluccius) and red shrimp (Aristeus antennatus) off Balearic Islands (western Mediterranean). Available annual catch per unit effort, recruitment and spawning stock biomass have been used as biological data. As environmental data, the meso-scale IDEA index and the large-scale North Atlantic Oscillation (NAO) and Mediterranean Oscillation (MO) indices have been used. To analyze possible links between these indices with the population dynamics of demersal resources, two non-linear approaches have been applied: (i) stock–recruitment relationships from Ricker and Beverton–Holt models, by sequentially incorporating environment factors; (ii) generalized additive modelling, both classical general and threshold non-additive models were considered. The latter simulate an abrupt change in explicative variables across different phases (time periods or climatic index values). The results have shown that two oceanographic scenarios around the Balearic Islands, associated with macro and meso-scale climate regimes, can influence the population dynamics of hake and red shrimp. This is especially true for recruitment, which seems to be enhanced during low NAO and IDEA indices periods. During these periods, colder-than-normal winters generate high amounts of cold Western Mediterranean Intermediate Waters (WIW) in the Gulf of Lions, which flow southwards and reach the Balearic Islands channels in spring, increasing the productivity in the area. This oceanographic scenario could also be favourable to the distribution of hake on the fishing grounds where the trawl fleet targets this species, increasing its accessibility to the fishery. Both spawning stock and abundance of red shrimp seems to be also enhanced by high MO index periods, which could reflect the increased presence of the saline and warm Levantine Intermediate Waters (LIW) in the study area, extending over the fishing grounds of this species. The proposed interactions can be useful to assess and manage these important demersal resources.     

岛屿自动综合原则和方法研究

自动制图综合是地图学的核心技术之一，随着信息社会和计算机制图技术的飞速发展，自动综合方法的研究成为制图自动化技术亟待解决的问题。在分析岛屿的制图特点的基础上，提出了岛屿自动综合的原则和方法，并给出了实际应用的例子。     

Clean energy and transport pathways for islands: A stakeholder analysis using Q method

Introducing sustainable ways to use energy and transport resources is of paramount importance for creating pathways to more liveable futures. Islands not interconnected to the main grid offer, because of their typically small size, short point-to-point travel distances that suit better than most landscapes the range limitations of today’s electromobile eco-systems. This makes them a unique test-bed that may assist researchers, businesses and policy-makers in developing a better understanding of the diverse opportunities and challenges that come with supporting electric-drive vehicle (EV) infrastructure investments that actively prioritise renewable energy sources (RES). This paper reports the findings of a Q method study that looks into the attitudes of 44 key stakeholders that have a thorough theoretical and empirical knowledge of the existing power and mobility portfolios in such islandic landscapes. Our analysis identifies and presents three distinct groups of stakeholders with different priorities and visions: the ‘Tech Enthusiasts’, the ‘Transform Transport First Supporters’ and the ‘Fiscal Focus Executives’. All our respondents agree on the need for radically transforming the current transport-energy nexus offering. They identify the importance of integrated and clean solutions and recognise that support of pilot applications is more critical than research and development (R&D). They also expect technological breakthroughs to increase market maturities and reduce renewable energy production costs and feel that end-users are still hesitant to buy EVs and need incentives to do so.     

Book review

The Cost of Environmental Protection: Regulating Housing in the Coastal Zone by Dan K. Richardson. Published by the Center for Urban Policy Research Rutgers University, 1976. 250 pp., $10.00.