Posidonia oceanica re-implantation technology of the marine gardeners is now operational on a large scale

Posidonia oceanica meadows form the most representative community of the Mediterranean shores. However, Posidonia oceanica meadows are fragile and in a bad way because of pollution and other nuisances. In several areas, Posidonia meadows have been replaced with vast deserts of dead ‘mattes’ or sand and mud.We owe to Cooper, now dead, the idea of using derelicts of Posidonia to regenerate the meadows in the areas where the aggressive factors were eliminated. For that purpose he perfected a kind of concrete frame called ‘constraint’ which offers optimal conditions for these cuttings to take root.So a study of scientific evaluation of Cooper's method has been undertaken in an experimental field of about 10 000 m² in the bay of Cannes. The ‘constraints’ were implanted over a period of 10 years, which gives particularly favourable conditions for studying their development. The work consisted of quantifying the vitality and the capacity of development of these cuttings with the help of classical tests such as the number of foliar bundles by surface unit, the biomass, the productivity, the number of running rhizomes and the surface of conquered ground. The results prove the effectiveness of the method which is now operational on a large scale.We can now foresee and hope for a reconquest of the ruined bottoms, provided of course we first remove the causes of the disappearance of the natural meadows of Posidonia oceanica.     

Wave interaction with ‘’-type breakwaters

The wave transmission, reflection and energy dissipation characteristics of ‘’-type breakwaters were studied using physical models. Regular and random waves in a wide range of wave heights and periods and a constant water depth were used. Five different depths of immersion (two emerged, one surface flushing and two submerged conditions) of this breakwater were selected. The coefficient of transmission, K_t, and coefficient of reflection, K_r, were obtained from the measurements, and the coefficient of energy loss, K_l was calculated using the law of balance of energy. It was found that the wave transmission is significantly reduced with increased relative water depth, d/L, whether the vertical barrier of the breakwater is surface piercing or submerged, where ‘d’ is the water depth and ‘L’ is the wave length. The wave reflection decreases and energy loss increases with increased wave steepness, especially when the top tip of the vertical barrier of this breakwater is kept at still water level (SWL). For any incident wave climate (moderate or storm waves), the wave transmission consistently decreases and the reflection increases with increased relative depth of immersion, Δ/d from −0.142 to 0.142. K_t values less than 0.3 can be easily obtained for the case of Δ/d=+0.071 and 0.142, where Δ is the height of exposure (+ve) or depth of immersion (−ve) of the top tip of the vertical barrier. This breakwater is capable of dissipating wave energy to an extent of 50–80%. The overall performance of this breakwater was found to be better in the random wave fields than in the regular waves. A comparison of the hydrodynamic performance of ‘’-type and ‘T’-type shows that ‘T’-type breakwater is better than ‘’-type by about 20–30% under identical conditions.     

Fish Larvae Abundance and Distribution in the Coastal Zone off Terminos Lagoon, Campeche (Southern Gulf of Mexico)

Fish larvae abundance and distribution in the coastal zone off Terminos Lagoon and their relation to the environmental features of the Lagoon inlets were analysed (1986–87). The sampling grid consisted of 24 stations extending between 0·5 and 10 km off the Lagoon, including both Terminos Lagoon Inlets; El Carmen and Puerto Real. A total of 23 families and 43 species were identified. Highest larval abundance was registered during the rainy period (July and September) when the fluvial discharges favoured the planktonic development. The lowest larval abundance was recorded in the period of northern cold wind (January–March) when the fluvial discharges decreased. Bray-Curtis index defined two groups of stations, corresponding to each of the lagoon inlets, persisting throughout the year. The first one, ‘ El Carmen ’, was characterized by larvae of Engraulidae and Gobiidae; estuarine-dependent inhabitants. This group could be considered as a functional extension of the Lagoon to the sea. The second group, ‘ Puerto Real ’, was characterized by highest larval abundance of marine dwellers (e.g.Opisthonema oglinumandHarengula jaguana). This situation suggests that the Puerto Real Inlet could be the main entrance of marine fishes into the Lagoon. These results indicate that the coastal zone off Terminos Lagoon constitutes an important nursery area both for species spending part of their life cycle linked to this estuarine system, and for marine species that migrate towards the Lagoon, carried by local currents.     

Architectural characteristics of two bed types of the seagrass Posidonia oceanica over different spatial scales

Seagrass beds occur in various morphological forms, ranging from small patches to continuous meadows. The endemic Mediterranean seagrass Posidonia oceanica forms dense and extensive stands that occur in several different morphotypes, including reticulate (seagrass interspersed with a different habitat type, such as bare sand) and continuous beds. This study, undertaken in the Maltese Islands, examined whether reticulate and continuous P. oceanica beds, located adjacent to each other and at similar depths, had different within-bed architectural characteristics. Five commonly used architectural measures (shoot density, number of leaves per shoot, mean leaf length, mean leaf width and shoot biomass) were measured from P. oceanica shoots collected from the two bed types at three different spatial scales: (1) tens of metres (‘small’ scale); (2) hundreds of metres (‘medium’ scale); and (3) kilometres (‘large’ scale). Results of 2-factor ANOVA (factor 1=bed type; factor 2=sampling locality) carried out at the three spatial scales indicated significant differences between the two bed types in shoot density (P<0.01) and leaf length (P<0.05) at the small scale, and in leaf number (P<0.05) at the large scale. Significant interactions were also apparent for shoot density (at the large scale) and for shoot biomass (at the medium scale). However, the results obtained did not indicate consistent architectural differences between the two P. oceanica bed types over the spatial scales considered. Spatial variations in within-bed architectural characteristics observed were therefore thought to be attributable mainly to the influence of local environmental factors. The findings are discussed with reference to the conservation and management of P. oceanica habitat.     

Ten myths concerning ecosystem approaches to marine resource management

Ecosystem approaches to marine resource management (EAM) offer comprehensive decision making based on rationalization of currently fragmented ocean policies and their implementation. However, despite the apparent utility in addressing these problems, EAM has also been criticized as being nonspecific, immature, invalid as a basis for decision making, and not fully supported by science. While it is commonly perceived that a paradigm shift in governance and science institutions awaits implementation to address these criticisms, in fact, ecosystem considerations are being incorporated more frequently, employing existing authorities as the basis for mitigation of sectoral impacts and for resource allocation. Management ‘best practices’ for EAM are emerging based on these experiences. Ten common criticisms of EAM, which I believe to be myths propagated primarily to maintain the status quo among sectoral interests, are discussed. Accelerated evolution of EAM will occur as science better articulates feedbacks, cumulative ecological effects and economic consequences framing policy choices, and more formal “rules of engagement” among sectors (e.g., fishing, coastal development, water quality, and energy) are negotiated. These operating procedures would be established under informal arrangements, in national law, and by international agreement. The management paradigm for marine resources is shifting and EAM will eventually be considered redundant with established practice.     

Seakeeping assessment of fishing vessels in conceptual design stage

The main idea of this paper is to identify functional relations between seakeeping characteristics and hull form parameters of Mediterranean fishing vessels. Multiple regression analysis is used for quantitative assessment through a computer software that is based on the SQL Server Database. The seakeeping attributes under investigation are the transfer functions of heave and pitch motions and of absolute vertical acceleration at stern, while the ship parameters influencing motion dynamics have been classified into two groups: displacement (Δ) and main dimensions (L, B, T), coefficients that define the details of the hull form (C_WP, C_VP, LCB, LCF, etc.).Four multiple regression models having different parameter combinations are here investigated and discussed, giving way to the so-called ‘Simple Model’, ‘Intermediate Model’, ‘Enhanced 1 Model’ and ‘Enhanced 2 Model’. The obtained results are more than satisfactory for seakeeping predictions during the conceptual design stage.     

Local effects of blue mussels around turbine foundations in an ecosystem model of Nysted off-shore wind farm, Denmark

The development of off-shore wind farms along the coastline of north-west Europe is rapidly increasing; it is therefore important to study how this will affect the marine environment. The present study modelled the growth and feed-backs of blue mussels in natural beds and on turbine foundations in an off-shore wind farm (OWF) located in a shallow coastal ecosystem by coupling a dynamic energy budget (DEB) model to a small-scale 3D hydrodynamic–biogeochemical model. The model results showed that blue mussels located higher up in the water column on turbine pillars achieved a 7–18 times higher biomass than those located on the scour protection because the former experience an enhanced advective food supply. Secondly, the high biomasses of blue mussels on foundations created local ‘hot spots’ of biological activity and changed ecosystem dynamics due to their feed-backs e.g. ingestion of microplankton and copepods, excretion of ammonium and egestion of faecal pellets. The model results were supported by field measurements around foundations of Chl a concentrations and biomasses of the fauna community. Our study emphasised that OWFs seem to be particularly favourable for blue mussels in the western Baltic Sea and that the functioning of the OWFs as artificial reef ecosystems depends upon how the blue mussels interact with their local pelagic and benthic environment.     

Classification of marine bioregions on the east coast of South Africa

Marine bioregional planning requires a meaningful classification and spatial delineation of the ocean environment using biological and physical characteristics. The relative inaccessibility of much of the ocean and the paucity of directly measured data spanning entire planning regions mean that surrogate data, such as satellite imagery, are frequently used to develop spatial classifications. However, due to a lack of appropriate biological data, these classifications often rely on abiotic variables, which act as surrogates for biodiversity. The aim of this study was to produce a fine-scale bioregional classification, using multivariate clustering, for the inshore and offshore marine environment off the east coast of South Africa, adjacent to the province of KwaZulu-Natal and out to the boundary of the exclusive economic zone (EEZ), 200 nautical miles offshore. We used remotely sensed data of sea surface temperature, chlorophyll a and turbidity, together with interpolated bathymetry and continental-slope data, as well as additional inshore data on sediments, seabed oxygen and bottom temperature. A multivariate k-means analysis was used to produce a fine-scale marine bioregionalisation, with three bioregions subdivided into 12 biozones. The offshore classification was primarily a pelagic bioregionalisation, whereas the inshore classification (on the continental shelf) was a coupled benthopelagic bioregionalisation, owing to the availability of benthic data for this area. The resulting classification was used as a base layer for a systematic conservation plan developed for the province, and provided the methods for subsequent planning conducted for the entire South African EEZ. Validation of the classification is currently being conducted in marine research programmes that are sampling benthic biota and habitats in a sampling design stratified according to the biozones delineated in this study.     

Reconciling customary and constitutional law: managing marine resources in Palau, Micronesia

As in much of Oceania, Palauan society of the pre-European contact era practiced sophisticated systems of tenure and management that extended to the fish and other resources of the surrounding coral reefs and lagoons. With its colonial experiences, the opening up of economic and social links with the outside world, and the introduction of highly efficient fishing technologies, Palau’s customary marine resource management systems have eroded.Like most Pacific Island countries, the Republic of Palau only recently gained independence from a western administrating nation. Its constitution, being based on western models, emphasizes democratic and egalitarian ideals. At the same time, it seeks to preserve and revitalize many aspects of customary Palauan society, particularly its institutions and processes of chiefly authority. These customs, however, are based on titled elitism and other principles contrary to those emphasized in the constitution. Through a combination of a series of court decisions that illustrate the incompatibility of the two bodies of law and a lack of any legislative initiative that could reconcile them, the exercise of purely customary authority has been relegated to matters of only minor importance. Thus, as in many Pacific Island nations, independence has contributed to the erosion of traditional tenure and management systems.Some recent village-level initiatives, however, may portend an important shift back toward decentralized, if not exactly traditional, control over the use of Palau’s inshore resources. The constitution’s critical provision that inshore resources are owned by the 16 states has allowed these relatively new village-level political and social units, with their mix of titled and elected leaders, to exert increasing control over inshore resources. They have done so in response to increasing resource scarcity owing to increasing fishing pressure, increasing demand by the booming marine-based tourism sector, and impending resource degradation from physical development. The effectiveness of these emerging local-level management regimes will be determined largely by the degree of support offered by the national government. Little has been forthcoming. The executive branch has been hesitant to support the marine property rights of the states, the judiciary has interpreted the constitution in a manner that has limited the authority of traditional leaders, and the legislature has not enacted laws that might guide the other two branches in interpreting and implementing the constitution with regard to either customary law or state ownership of marine resources.     

Biogeochemistry of sterols in plankton, settling particles and recent sediments in a cold ocean ecosystem (Trinity Bay, Newfoundland)

In the context of a multidisciplinary study to determine current and past ecosystem health and the relative contributions of sources of organic matter (marine vs. terrestrial and natural vs. anthropogenic input), sterols were determined in plankton, settling particles and sediments from Trinity Bay, Newfoundland, a sub-polar Atlantic Ocean ecosystem. The centric diatoms Chaetoceros spp., Thalassiosira spp. and Leptocylindrus danicus were all prominent in the plankton samples, and centric diatoms predominated in the settling particles. Plankton samples contained 0.4±0.4 mg/g dw (1995) or 1.4±1.3 mg/g dw (1996) total sterols, with cholesta-5,24-dien-3β-ol (mean 26% of total sterols), cholest-5-en-3β-ol (24%) and cholesta-5,22(E)-dien-3β-ol (13%) chief among these, denoting diatom and zooplankton sources. In settling particles, the prominence of cholesta-5,24-dien-3β-ol (24%), cholest-5-en-3β-ol (24%), cholesta-5,22(E)-dien-3β-ol (13%) and 24-methylcholesta-5,22(E)-dien-3β-ol (9%) again suggested mainly marine sources. The sterol composition of plankton and settling particles from different sampling periods showed a high degree of consistency. Higher plant C₂₉ sterols (notably 24-ethylcholest-5-en-3β-ol, 9–26%) were prominent in sediments from both inshore and offshore sites. No decreasing trend in total or individual sterols was observed down the 30-cm sediment cores, suggesting good overall preservation. No 5β-stanols such as 5β-cholestan-3β-ol (coprostanol) were detected in offshore sediments, plankton or settling particles, with only low levels (5β-cholestan-3β-ol max. 4.4%, 5β-cholestan-3α-ol max. 5.1%) in certain inshore sediments. This suggests that raw sewage discharges in rural Newfoundland are being efficiently degraded or dispersed, or that inputs are highly localized. Source apportionation of organic matter in the sediment samples based on sterol composition was attempted. This highlighted the large terrestrial contribution to the sterols in marine sediments (up to 58% of sterols inshore, 24% offshore) and suggests either degradation or effective recycling of marine sterols.     

Interaction between water flow and oxygen deficiency on growth in the infaunal brittle star Amphiura filiformis (Echinodermata: Ophiuroidea)

Interactions between ‘oxygen concentration’ (normoxia: >80% oxygen saturation, and hypoxia: 18% oxygen saturation) and ‘water flow velocity’ (low: 0.1 cm s⁻¹, and moderate: 0.5 cm s⁻¹) were studied on growth rates in the brittle star Amphiura filiformis in a flow-through aquaria system. Effects of ‘sublethal predation’ on growth rates were investigated as ‘number of amputated arms’ (1 and 3 arms) and ‘amputation of the disk’. A significant interaction between oxygen concentration and water flow velocity was observed in mean arm regeneration rate, but in both flow velocities higher mean arm regeneration rates were observed in normoxia compared to hypoxia. In hypoxia a positive response in arm regeneration rate was observed in moderate flow compared to low flow velocity. In normoxia, however, no response to flow velocity was observed. The latter observation indicates that Amphiura filiformis is able to maintain the ventilation of the burrow at low flow velocities, but in low oxygen concentrations hydrodynamic forces seem to affect growth. A significant interaction between oxygen concentration and disk amputation was observed in both arm and disk regeneration rates, indicating that the disk is the major organ for gas exchange in this species. The number of arms amputated, however, did not affect mean arm regeneration rate. The results obtained in this study suggest that the secondary production in subtidal infaunal populations could be negatively affected by low oxygen concentrations and that this response is even more negative in combination with low flow velocities in the near-bottom water.     

Ancient Mediterranean harbours: a heritage to preserve

Management and protection in coastal areas mainly addresses the natural environment and rarely addresses cultural and technical resources. This paper represents a plea for diverting more attention to some valuable historical features which exist, abandoned, along the Mediterranean shores.Along these shores a UN inventory identified some 1255 submerged archaeological coastal sites, many of which showed no signs of any protection from the attack of the sea and of growing coastal tourism. Many of them are remnants of harbour structures which are over 2000 years old.A condensed overview is given of the historical evolution of ancient harbour engineering, particularly related to the Roman age, describing the most interesting and innovative technological aspects, which could still add a valuable insight to the design of modern coastal structures. This knowledge was initially derived from literary and pictorial evidence and is now greatly expanded by the recent discoveries of underwater archaeology and by the developments of remote sensing technology.Co-operation between coastal engineers and archaeologists is encouraged, both for the preliminary surveys before the execution of new coastal works and for the interpretation, defence and revaluation of discovered maritime remains.Finally, recommendations for the restoration and creation of major ancient port sites as museums, possibly within innovative ‘coastal submarine archaeological parks’, are given.     

Upstream dams and downstream clams: growth rates of bivalve mollusks unveil impact of river management on estuarine ecosystems (Colorado River Delta, Mexico)

We studied how the extensive diversion of Colorado River water, induced by dams and agricultural activities of the last 70 years, affected the growth rates of two abundant bivalve mollusk species (Chione cortezi and Chione fluctifraga) in the northern Gulf of California. Shells alive on the delta today (‘Post-dam’ shells) grow 5.8–27.9% faster than shells alive prior to the construction of dams (‘Pre-dam’ shells). This increase in annual shell production is linked to the currently sharply reduced freshwater influx to the Colorado River estuary. Before the upstream river management, lower salinity retarded growth rates in these bivalves. Intra-annual growth rates were 50% lower during spring and early summer, when river flow was at its maximum. Growth rates in Chione today are largely controlled by temperature and nutrients; prior to the construction of dams and the diversion of the Colorado River flow, seasonal changes in salinity played an important role in regulating calcification rates.Our study employs sclerochronological (growth increment analysis) and geochemical techniques to assess the impact of reduced freshwater influx on bivalve growth rates in the Colorado River estuary. A combination of both techniques provides an excellent tool to evaluate the impact of river management in areas where no pre-impact studies were made.     

The need and practice of monitoring, evaluating and adapting marine planning and management—lessons from the Great Barrier Reef

An increasing number of scientists and resource managers recognise that successful marine management approaches, including marine spatial planning (MSP), cannot occur without effective monitoring, evaluation and adaptation. These basic components are necessary to ensure that any marine planning or marine management measures are both effective and efficient. While a number of fundamental principles for marine monitoring, evaluation and adaptive management exist, there are varying levels of understanding about how these should be undertaken and what they may achieve. Challenges include the development of realistic and measurable objectives and indicators against which effectiveness can be practically measured. The matter becomes even more complicated as the focus of marine planning and management strategies changes from ‘single species’ to ‘habitats’ and ‘ecosystems’ that may enable a diversity of permitted uses consistent with a variety of overall objectives. Over the last 30 years, the Great Barrier Reef Marine Park (GBRMP) has successfully established a multiple-use spatial management approach that allows both high levels of environmental protection and a wide range of human activities. Drawing on this unique long-term experience in the GBRMP, this article discusses key aspects of effective monitoring and evaluation, and summarises lessons learned from over two decades of adaptive management.     

Dietary Studies on the Predatory Fishes of the Norman River Estuary, with Particular Reference to Penaeid Prawns

The predatory fish community and their prey in the Norman Rivere estuary, Gulf of Carpentaria Australia, are compared with the communities of other tropical inshore areas, to investigate patterns of predation in tropical inshore areas particularly in relation to penaeid prawns. Abiotic factors (turbidity, freshwater input) and diversity of habitat types affect the composition of both prey and predator communities, resulting in large differences in the communities of tropical inshore waters. The stomach contents of 2059 predatory fish from the Norman River estuary were analysed over four sampling trips in the wet and dry seasons. The stomachs of 61% (1255 fish) of 54 species contained a total of 676·2 g (dry weight) of food, while 39% (804 fish) were empty. Teleosts were the main component of the diet (by dry weight) of 13 of the 22 species analysed, followed by annelids for two species. Five species had only teleosts in their stomachs. Most predator species ate benthic or bentho-pelagic prey, while three species—Rhizoprionodon taylori, Scomberoides commersonianusandLeptobrama mulleri—ate mainly pelagic prey. Although 19 species ate some penaeids, onlyPolydactylus sheridaniate little else. This species,Lates calcariferandEleutheronema tetradactylumate 94·5% of all the penaeid prey and 97·9% of all the commercially important penaeid prey recorded in the study. Penaeid predation indices (calculated from gillnet catch rates, proportion of penaeids in the diet and a consumption rate of 3% body weight per day) were 0·23 g of penaeid per net-metre per day forP. sheridani, 0·15 forL. calcariferand 0·03 forE. tetradactylum. Commercially important penaeid predation indices were 0·11, 0·13 and 0·01, respectively. These values are intermediate between those previously recorded for the main penaeid predators in other inshore areas of the Gulf of Carpentaria (Embley River estuary and Groote Eylandt).     

Recovery of Mytilus edulis L. from chronic oil exposure

Previous laboratory studies¹ have shown that physiological and cellular processes of Mytilus edulis are affected by exposure to low and environmentally realistic concentrations of oil. However, there is little information concerning the rate of recovery from oil exposure and the extent to which physiological recovery may be related to the depuration of hydrocarbons from the tissues. The present study has shown a marked reduction in the feeding rate and scope for growth of mussels exposed to two concentrations of diesel oil (30 and 130 μg/litre) for 8 months. During recovery from oil exposure the depuration of hydrocarbons from the tissues was concomitant with the recovery of physiological performance. Mussels exposed to high oil concentrations (‘high-oil’ mussels) were found to recover more rapidly than those exposed to low oil concentrations (‘low-oil’ mussels), both in terms of depuration and scope for growth, and there was evidence of ‘catch-up’ growth. Recovery of both low- and high-oil mussels was complete after approximately 55 days.     

Fishing industry and related perspectives on the issues raised by no-take marine protected area proposals

In the face of growing calls for no-take marine protected areas (NTMPAs), the views of fishing industry representatives in south-west (SW) England on related issues are analysed. Only 23% thought NTMPAs were the way forward and a range of concerns were expressed, e.g. that the ‘terrestrial’ protected areas approach and related biodiversity conservation objectives will be extended to the seas, and that fish yield reductions from the loss of access to NTMPAs are very unlikely to be compensated for through spillover/export. Some interesting approaches to ameliorating these concerns emerged, such as being open and honest that NTMPAs are primarily intended to achieve biodiversity conservation benefits, reducing uncertainty concerning the potential for any secondary fisheries spillover/export benefits, justifying NTMPAs on an objective, rational basis rather than on a subjective, precautionary basis, and the quid pro quo streamlining of wider fisheries management approaches. This research reveals a more diverse range of perspectives amongst fishing industry representatives on the issues raised by NTMPA proposals than is often assumed.     

基于海洋生态文明建设的我国近岸海域综合治理

为持续改善海洋生态环境和提升海洋生态服务功能,进一步促进海洋生态文明建设和沿海地区可持续发展,文章梳理我国已开展的近岸海域综合治理工作内容,深入分析存在的问题,并基于目标和任务提出对策措施。研究结果表明:20世纪90年代以来,我国陆续实施一系列近岸海域综合治理项目,取得显著成效,但在整体规划、管理机制、统筹协调和科学支撑方面仍存在不足;基于近岸海域综合治理在海水质量、生态服务功能、人居环境和能力建设方面的目标和任务,应加强顶层设计、完善运行监管、坚持陆海统筹和强化基础研究。     

Sustainable development and integrated coastal management

Agenda 21, the 40-chapter action plan, agreed to by all nations participating in the 1992 Earth Summit represents an ambitious effort to provide policy guidance across the entire spectrum of environment, development, and social issues confronting mankind. In the area of oceans and coasts (Chapter 17 of Agenda 21), the Earth Summit underscored that the management of oceans and coasts should be ‘integrated in content and anticipatory in ambit.’To assist those responsible for implementing the Earth Summit guidelines on ocean and coastal management, this article first reviews the fundamental shift in paradigm reflected in the Earth Summit agreements as well as the specific recommendations contained in Chapter 17. Next, the article examines the central concept of ‘integrated management,’ noting both its importance and its limits. A general or ‘synthesis’ model of ‘integrated coastal management’ is then presented, addressing such questions as management goals, what is being managed, where, how, and by whom.In a concluding section, methods are proposed whereby the general or ‘synthesis model’ can be tailored to diverse national contexts, involving varying physical, socio-economic, and political conditions.