Critical Marine Habitats Research Articles

Biodiversity of coral reefs and associated seagrass beds in Quy Nhon Bay, Binh Dinh Province

The distribution of critical marine habitats in Quy Nhon Bay, Binh Dinh Province, was assessed with the combination of resolution of Google Earth images and local knowledge through local consultations and ground truthing using small boats to check the sites supporting coral reefs and seagrass beds with local involvement. Detailed surveys on species diversity and conditions of marine habitats were conducted at 24 sites of coral reefs and four sites of seagrass beds at three sites (Nhon Ly, Nhon Hai, Ghenh Rang, and Nhon Chau) in 2016–2017. More than 152 ha of coral reefs, 5 ha of seagrass beds, and 720 species belonging to 7 key groups (290 species of fishes; reef-building corals: 194, molluscs: 123, seaweeds: 47, echinoderms: 40, crustaceans: 20 and seagrasses: 6 species) associated with the above habitats were recorded in the Bay. Among them, 92 species were facing different threats, in which 3 species were endangered (EN), including branching corals (Alveopora minuta), flat pen shells (Atrina vexillum), and top shells (Tectus pyramis); 38 species at vulnerable (VU); and 51 species at near threatened (NT) following the IUCN Red List and Vietnam Red Book. In general, the coral reefs and seagrass beds at Bai Dua and Seo Island (Nhon Ly); Kho Nho Island, Bo Dap (Nhon Hai); S. Ngang Island, Bai Nam and Bai Nom of Dat Island (Ghenh Rang); Da Ban, Bai Lang, Bai Lang Ba and Ong Gia Island (Nhon Chau) supported higher diversity and better conditions than other sites. Establishing restricted zones at these sites is an urgent need, but it also holds the premise of sustainable utilization and conservation of resources in the future.

Diving into warming oceans: Assessing 3D climatically suitable foraging areas of loggerhead sea turtles under climate change

Climate change impacts on marine species have been mainly studied considering only the sea surface despite the fact that most species depend on habitats at different depths. With sea temperatures warming unevenly across depths, identifying critical marine habitats while considering the three-dimensionality of the seascape is a major conservation challenge. Unfortunately, this research field remains largely unexplored and only few examples permit the identification of vertically coherent areas. Here, we developed a climate niche-based framework to delineate critical areas across different depths and assess their consistency over space and time. We use loggerhead sea turtles as a model species to identify climatic suitable areas for the present and future three-dimensional marine space of the Mediterranean Sea, using temperatures from three bathymetric layers of 5 m, 25 m and bottom neritic waters. We analyzed both juvenile and adult sea turtles, which use different depth-related habitats. Our analysis revealed that the coherence among thermal suitable habitats of different depths varied across the different life stages. Although near-surface habitats of juvenile sea turtles spanned across a vast area of the Mediterranean, their water-column habitats were spatially restricted. Near-surface, deep and water-column habitats of adults shared similar distribution patterns. Under future conditions, all types of three-dimensional habitats seemed to primarily maintain thermal stability, however, even opposite changes were predicted for different depths. Our study provides an advanced spatial mapping of sea turtle habitats, highlighting the significance of the three-dimensional marine space and how the selection and combination of specific bathymetric zones may impact patterns in distribution.

Seagrass repression by green turtles (Chelonia mydas) around Taiping Island in the south China sea: Experimental evidence and management insights

Seagrass meadows serve as critical marine habitats, offering numerous benefits to both humans and wildlife. Taiping Island, situated in the South China Sea, has been historically known for its abundant seagrass meadows. However, satellite imagery suggested there was a low density of seagrasses around Taiping Island. On the other hand, many green turtles (Chelonia mydas) were observed from the shore. To investigate this phenomenon, we conducted drone surveys of the shallow reefs and discovered a density of 902 ± 601 (mean ± SD) individual turtles per square kilometer during high tides. In addition, we conducted a cage experiment to test the hypothesis that large herbivores are impacting seagrass abundance negatively. The results indicated that the blade lengths of seagrasses in cages were significantly longer than those outside. It is likely that large herbivores such as green sea turtles are the key consumers of seagrass on the shallow reef flats of Taiping Island. Accordingly, further research and management should take into account that the increasing number of sea turtles may deplete the seagrasses and have an impact on the seagrass ecosystems.

Threatened North African seagrass meadows have supported green turtle populations for millennia

"Protect and restore ecosystems and biodiversity" is the second official aim of the current UN Ocean Decade (2021 to 2030) calling for the identification and protection of critical marine habitats. However, data to inform policy are often lacking altogether or confined to recent times, preventing the establishment of long-term baselines. The unique insights gained from combining bioarchaeology (palaeoproteomics, stable isotope analysis) with contemporary data (from satellite tracking) identified habitats which sea turtles have been using in the Eastern Mediterranean over five millennia. Specifically, our analysis of archaeological green turtle (Chelonia mydas) bones revealed that they likely foraged on the same North African seagrass meadows as their modern-day counterparts. Here, millennia-long foraging habitat fidelity has been directly demonstrated, highlighting the significance (and long-term dividends) of protecting these critical coastal habitats that are especially vulnerable to global warming. We highlight the potential for historical ecology to inform policy in safeguarding critical marine habitats.

Natural threat to the Turkish straits sea area: the mucilage

The Turkish Straits Sea Area comprises the Istanbul, the Canakkale Straits, and the Marmara Sea. The area is the most essential natural waterway connecting the continents of Asia and Europe. However, as of May 2021, it is polluted with Mucilage which is a slippery mass of microorganisms mostly clustered together, covering large areas, mainly in the Sea of Marmara and locally in the Turkish Straits. Unicellular organisms release fatty acids from the body under stressful environmental conditions. The Turkish Straits Sea area, which also connects the Black Sea and the Aegean Sea, constitutes a critical marine habitat among marine species. On the one hand, ballast operations create a sticky surface on the ship's hull and the underwater structure in contact with water. At the same time, there is also the necessity of cooling the ship's machinery with seawater. Ship cooling systems use seawater to cool the ship's engine block, while filtration prevents damage to the system. However, the mucilage effect affects the control of the vessel by causing clogging of the filters that serve to protect the system. The fact that the water taken by filtration is affected by Mucilage, clogging, and involving the outer surface of the ship affects the safety of the vessel at a high level. This research article tries to explain the damage and effects of Mucilage on ships sailing in the Turkish Straits.

Marine habitats and related fishery resources in Ly Son and adjacent waters in the Northern part of Quang Ngai province

The study assessed the distribution of key marine habitats and related fishery resources and spawning and nursery grounds of target species in the waters of Ly Son islands and adjacent locations of Tra Bong and Sa Ky estuaries using data from analysis of the Sentinel-2 satellite image and ground-truthing. There were about 1,787 ha of coral reefs, 117.3 ha of seagrass beds, and 309 ha of nipa palm (Nypa fruticans) distributed in this area, in which the water surrounding Ly Son marine protected area (MPA) supported more than 1,706 ha of coral reefs and 116 ha of seagrass beds. The area also supported 12 nursery grounds of 10 target resources, including giant trevally, mangrove-red snapper, orange-spotted spinefoot, orange-spotted grouper, malabar grouper, barramundi related to nipa palms in Tra Bong and Sa Ky estuaries. In contrast, sea cucumbers, turbo snails, top shells, and giant clams were associated with coral reefs in Ly Son MPA. Related fishery resources, spawning, and nursery grounds of target species involved 8 consultations of local experienced fishermen and a field investigation of the presence of spawning and nursery grounds from November 2019 to September 2020. A total of 1,278 tonnes of commercial resources were harvested in the coral reefs and some 4.647 thousand juveniles of fish and crabs were collected from the adjacent estuaries, in which some essential species of reef fishes indicate linkages between juveniles collected from the nipa palm and seagrass beds in Tra Bong and Sa Ky estuaries and adults fished in the coral reefs in Ly Son MPA. So, conservation and management of exploitation of fish juveniles related to the nipa palm and seagrass beds in Tra Bong and Sa Ky estuaries are considered important solutions for the maintenance of the linkages of fish resources associated with critical marine habitats and fisheries in the waters of Ly Son MPA and adjacent locations in the future.

Oil spill assessment maps of the central Salish Sea – Marine seafloor & coastal habitats of concern – A tool for oil spill mitigation within the San Juan Archipelago, Washington State, USA

The potential for oil spills within the San Juan Archipelago of the central Salish Sea of Washington State, USA, has been an increasing concern for some time. Within this region, the spectacular islands, coastline, and underwater environment has drawn tourists, fisher people, residents, and researchers from around the world to play, live, and study. The diverse biological resources of the region provide sustenance for many of the islanders and supports a valuable tourist industry for whale watching; salmon, crab, and shrimp fishing; and underwater diving – all of which can be adversely impacted by an oil spill.The present plans to ship more hydrocarbon products, including diluted bitumen (dilbit), from transfer sites located along the coastline of mainland British Columbia, Canada, has the potential to increase tanker vessel traffic seven-fold through the San Juan Archipelago (Seattle Times, June 22, 2019). This, along with other types of marine traffic such as cruise ships, tug-and-tow barges, articulated tank barges, bulk carriers, freighters, and general cargo shipping will increase the risk of a collision, grounding, or other events that may lead to a significant oil spill. To date, the central Salish Sea region is only marginally prepared for an oil spill tracking, containment, and recovery action. Thus, a need exists to stage equipment for the mitigation of an oil spill event if critical marine habitats are to be protected. We focus on some of these critical benthic habitats such as for rockfish (Sebastes spp.), lingcod (Ophiodon elongatus), the forage fish Pacific sand lance (Ammodytes Personatus), eelgrass (Zostera marina) meadows that are recruitment habitat for herring (Clupus herengus), and kelp (Nerocystis luetkeana) forests.To strategically locate or assemble any mitigation apparatus for a rapid response to an oil spill, a map showing critical marine habitats is a necessity. Such a map should highlight the most critical habitats along the marine transportation corridors (primarily Rosario Strait, Haro Strait, and Guemes Channel) as well as the relatively isolated sounds and bays including Padilla Bay, Samish Bay, and Fidalgo Bay that could act as depotcenters for oil accumulation. This study addresses that need and usefulness for such a map, as no longer can it be said that what lies beneath the sea's surface is “out-of-sight”, and thus “out-of-mind”. This means that this study is critical to the development of realistic Natural Resources Damage Assessment (NRDA) settlements and can be used to inform developments of future Geographic Response Plans (GRPs) of the State of Washington. The process described here is not unique to the central Salish Sea and can be used as a template elsewhere for NRDA's and other protective measures after being modified to account for specific habitats deemed critical to those areas.

Spatial Dynamics of Two Host-Parasite Relationships on Intertidal Oyster Reefs

Intertidal reefs comprised of the eastern oyster (Crassostrea virginica) have long experienced habitat loss, altering habitat patch characteristics of size and distance from edge to interior, potentially influencing spatial dynamics of host-parasite relationships. Using two parasitic relationships, one between eastern oyster host and parasitic oyster pea crab (Zaops ostreum) and the other between a xanthid crab (Eurypanopeus depressus) and a parasitic rhizocephalan barnacle (Loxothylacus panopaei), we examined how host-parasite population characteristics varied on intertidal reefs by season, reef size, and distance from edge to interior. Pea crab prevalence was more related to habitat characteristics rather than host density, as pea crab prevalence was the highest on large reefs and along edges, areas of comparatively lower oyster densities. Reef size did not influence densities of parasitized or non-parasitized xanthid crabs, but densities varied from edge to interior. Non-parasitized xanthids had significantly lower densities along the reef edge compared to more interior reef locations, while parasitized xanthid crabs had no significant edge to interior pattern. Organismal size had a varied relationship based upon habitat characteristics, as pea crab carapace width (CW) varied interactively with season and reef size, whereas CW of parasitized/non-parasitized xanthid crabs varied significantly between edge and interior locations. These results demonstrated that influential habitat characteristics, such as patch size and edge versus interior, are both highly species and host-parasite specific. Therefore, continued habitat alteration and fragmentation of critical marine habitats may further impact spatial dynamics of host-parasite relationships.

Marine ecosystem restoration in a changing ocean

Multiple human impacts on natural ecosystems cause ongoing widespread habitat loss, with consequent decline of biodiversity and ecosystem services. Seas and oceans, the largest biomes of the biosphere, show increasing numbers of degraded habitats. Ecological restoration offers a major tool to reverse this trend and recover biodiversity, along with human health and well‐being. The United Nations Decade on Ecosystem Restoration promotes global‐scale restoration of degraded habitats and we can exploit lessons learned from terrestrial restoration projects to improve and accelerate marine ecosystem restoration science, practice, and policy. Nonetheless, major differences in land and sea limit direct transfer of terrestrial approaches. Limited ecosystem baselines, greater stochasticity and connectivity, longer timescales needed for effective restoration, associated high costs and advanced technologies required to access and intervene in marine environments (especially in the deep sea), and difficulty in scaling up restoration efforts all hinder the effectiveness and expansion of marine ecosystem restoration. Pilot actions in European waters over ca 5 years in the EU‐funded MERCES consortium (Marine Ecosystem Restoration in Changing European Seas) have identified and developed new, promising tools and strategies to catalyze restoration actions, including engagement of funding organizations, governmental bodies, scientists, and citizens. We are now better positioned to implement restoration actions on a wide range of protected, vulnerable, and critical marine habitats, including seagrass meadows, algal forests, shallow rocky shore, and even some deep‐sea habitats. Outcomes from the MERCES project support future restoration initiatives by demonstrating restoration potential in the marine environment.

Evaluating benthic impact of the Gulf of Maine lobster fishery using the Swept Area Seabed Impact (SASI) model

The Magnuson–Stevens Fishery Conservation and Management Act mandates US fisheries minimize adverse effects of fishing on essential fish habitat (EFH). The Gulf of Maine (GoM) American lobster (Homarus americanus) fishery is the most valuable US fishery and can deploy more than three million traps annually. To date, the impact of this fishery on benthic EFH has not been addressed quantitatively. To evaluate the impact of the GoM lobster fishery on EFH, we incorporated lobster fishing effort into a model linking habitat susceptibility and recovery to area impacted by fishing gear: the Swept Area Seabed Impact model. Impact to EFH was localized along the coast and highest along midcoast Maine. Upwards of 13% of the benthos is in the process of recovery, but between 99.92% and 99.96% of initially affected habitat fully recovers. These estimates suggest that lobster fishing negligibly contributes to accumulation of EFH damage in the GoM due to the expansive area fished and the small footprint of each trap. Identifying areas of persistent impact is crucial in developing effective fisheries management for critical marine habitats.

From South Asia to the world: embracing the challenge of global sustainable nitrogen management

From South Asia to the world: embracing the challenge of global sustainable nitrogen management

Hydrogen sulphide sensitivity and tolerance in genetically distinct lineages of a selfing mangrove fish (Kryptolebias marmoratus).

Mangroves are critical marine habitats. High hydrogen sulphide (H2S) is a feature of these important ecosystems and its toxicity creates a challenge for mangrove inhabitants. The mangrove rivulus (Kryptolebias marmoratus) is a selfing, hermaphroditic, amphibious fish that can survive exposure to 1116μM H2S in the wild. These fish rely on cutaneous respiration for gas and ion exchange when emerged. We hypothesized that the skin surface is fundamentally important in H2S tolerance in these mangrove fish by limiting H2S permeability. To test our hypothesis, we first disrupted the skin surface in one isogenic lineage and measured H2S tolerance and sensitivity. We increased water H2S concentration until emersion as a measure of the ability to sense and react to H2S, which we refer to as sensitivity. We then determined H2S tolerance by preventing emersion and increasing H2S until loss of equilibrium (LOE). The H2S concentration at emersion and LOE were significantly affected by disrupting the skin surface, providing support that the skin is involved in limiting H2S permeability. Capitalizing on their unique reproductive strategy, we used three distinct isogenic lineages to test the hypothesis that there would be genetic differences in H2S sensitivity and tolerance. We found significant differences in emersion concentration only among lineages, suggesting a genetic component to H2S sensitivity but not tolerance. Our study also demonstrated that external skin modifications and avoidance behaviours are two distinct strategies used to tolerate ecologically relevant H2S concentrations and likely facilitate survival in challenging mangrove habitats.

Ecological costs of climate change on marine predator-prey population distributions by 2050.

Identifying and quantifying the effects of climate change that alter the habitat overlap of marine predators and their prey population distributions is of great importance for the sustainable management of populations. This study uses Bayesian joint models with integrated nested Laplace approximation (INLA) to predict future spatial density distributions in the form of common spatial trends of predator–prey overlap in 2050 under the “business‐as‐usual, worst‐case” climate change scenario. This was done for combinations of six mobile marine predator species (gray seal, harbor seal, harbor porpoise, common guillemot, black‐legged kittiwake, and northern gannet) and two of their common prey species (herring and sandeels). A range of five explanatory variables that cover both physical and biological aspects of critical marine habitat were used as follows: bottom temperature, stratification, depth‐averaged speed, net primary production, and maximum subsurface chlorophyll. Four different methods were explored to quantify relative ecological cost/benefits of climate change to the common spatial trends of predator–prey density distributions. All but one future joint model showed significant decreases in overall spatial percentage change. The most dramatic loss in predator–prey population overlap was shown by harbor seals with large declines in the common spatial trend for both prey species. On the positive side, both gannets and guillemots are projected to have localized regions with increased overlap with sandeels. Most joint predator–prey models showed large changes in centroid location, however the direction of change in centroids was not simply northwards, but mostly ranged from northwest to northeast. This approach can be very useful in informing the design of spatial management policies under climate change by using the potential differences in ecological costs to weigh up the trade‐offs in decisions involving issues of large‐scale spatial use of our oceans, such as marine protected areas, commercial fishing, and large‐scale marine renewable developments.

Morphological plasticity in a Fijian Seagrass: Halophila ovalis subsp. bullosa

Seagrasses are marine flowering plants found along both tropical and temperate coastlines; they possess great ecological importance as nurseries, nutrient sinks, and providers of critical marine habitat. Understanding the distribution and diversity of seagrass habitats is important for their conservation and management, however this is impeded by varying species’ diversity, the extensive distribution of seagrasses and taxonomic uncertainty. In the Fiji Islands, the tropical seagrass Halophila ovalis and its subspecies H. ovalis bullosa are the subject of taxonomic controversy, as a singular morphological characteristic distinguishes the two. This characteristic is the bullated, or blister-like leaves of the latter, compared to the smooth leaves of the former, which in some instances have been observed on the same plant (S.S., pers. obs.). This study examined material from both taxa, along with three other seagrass species (Halodule pinifolia, H. uninervis and Syringodium isoetifolium; total n=95) and used independent morphological and molecular barcoding approaches to assess the conspecificity of the two Halophila taxa. Examination of vegetative and reproductive characters was not able to distinguish between H. ovalis and H. ovalis subsp. bullosa, while phylogenetic reconstructions using ITS2, matK and trnH-psbA barcodes supported their monophyly. We recommend revision and merger of these taxa, while the approach used here is highly useful for taxonomic resolution in other seagrass taxa, for their conservation, restoration and management.

An ecosystem based approach to the assessment and governance of the Bay of Bengal Large Marine Ecosystem

The Bay of Bengal Large Marine Ecosystem (BOBLME) is one of the largest and most important globally. In recent years Bangladesh, India, Indonesia, Malaysia, Maldives, Myanmar, Sri Lanka and Thailand have come together to build consensus around a Strategic Action Programme (SAP) with the support of the Global Environment Facility (GEF) International Waters, Norway, Sweden and the Food and Agriculture Organisation of the United Nations (FAO). The Transboundary Diagnostic Analysis (TDA) process identified a number of key issues including overexploitation of marine living resources, degradation of critical habitats and pollution and water quality. The TDA process identified several key drivers which contribute to these issues. These include socio-economic drivers, institutional, legal and administrative drivers and climate change. The agreed SAP identified four key objectives including that fisheries and other marine living resources are restored and managed sustainably; degraded, vulnerable and critical marine habitats are restored, conserved and maintained; coastal and marine pollution and water quality are controlled to meet agreed standards for human and ecosystem health; and social and economic constraints are addressed, which should lead to increased resilience and empowerment of coastal people. Analysis of the BOBLME SAP shows that just over 70% of the identified activities are being undertaken to some extent by countries already. SAP implementation recognises the importance of approaches such as the Ecosystem Approach to Fisheries (EAF), Integrated Coastal Management (ICM) and the focus on Small Scale Fisheries. Whilst BOBLME countries vary considerably in their governance arrangements and capacity to implement, they recognise the importance of regional coordination and cooperation to address transboundary issues.

MARINE PROTECTED AREA NETWORK DESIGN: CASE STUDY OF MALUKU PROVINCE


 Since 2014, the Ministry of Marine Affairs and Fisheries has started to initate the development of MPA Network in several provinces in Indonesia. The objective of this study is to provide scientific recommendations to the government and stakeholders on MPA Network design that maximizes the ecological functions, protects critical marine habitats and maintains fisheries stocks. Multi-stages spatial analysis and larva connectivity modelling using the best available data in a provincial level were applied. Until December 2015, Maluku Province had seven MPAs with a total of 288,414 ha. Based on spatial analysis, those MPAs had good Replication of critical habitats, but low Representation of critical habitats (3,8% from 20% of ideal representation percentage) that were protected within MPAs. Besides that, only five out of seven MPAs that were connected, i.e. the distance between MPAs is less than 100 km, meanwhile the other two MPAs were isolated from other MPAs. Maluku Province also had several nodes of strong larva connectivity values. This study demonstates the potential to develop an MPA Network in Maluku Province under these several considerations: (1) build new MPAs in several locations such as Buru Island, Maluku Barat Daya, Aru Islands, etc. (2) enlarge the existing MPAs, especially the small size MPAs, and (3) strengthen the roles and functions of management bodies in each MPA and promote an integrated management plan development with all MPA management bodies.
 
 
 Keywords
 MPA Network, Maluku Province, 3K (Representation, Replication and Connectivity), Larva Connectivity

Building the future of MPAs – lessons from history

Abstract Marine protected areas (MPAs) have a long history, originating in traditional and cultural initiatives often focused on reserving resources for food security. A handful of ‘parks’ were established between the 1870s and 1940s and, following World War II, increased awareness of threats to the ocean led to global programmes that started in the 1970–1980s. Initially IUCN became the leader, piloting a science‐based ‘critical marine habitats’ approach, by which MPAs were aimed at conserving the healthiest and most diverse ecosystems, endangered and charismatic species, and high‐profile habitats. During the 1970s, with the support of WWF, UNESCO, UNEP, and growing national efforts, the MPA concept evolved to include biosphere reserves, marine reserves and sanctuaries, large ocean reserves, and other designations that aimed to reconcile long‐term protection with human use. From the 1980s, MPAs greatly expanded in number and scope. By the turn of the millennium, MPAs were proliferating, and principles and methodologies were available to guide their establishment and management in a harmonized manner. Zoning for different uses was widespread, but questions were being raised about the efficacy of biodiversity conservation in areas where extractive uses were permitted. MPA implementation accelerated once targets were introduced by the Convention on Biological Diversity. Campaigns and fundraising by non‐governmental organizations and further national efforts resulted in a rapid increase although, by 2015, less than 4% of ocean surface was protected. Current challenges include: (1) understanding the role of MPAs in maintaining ecosystem services, fishery management, climate change adaptation and mitigation, and other emergent problems; (2) more rigorous network design; (3) effective governance and demonstration of ‘success’; and (4) integrating MPAs with marine spatial planning. While MPAs have provided one of the most viable and politically acceptable approaches to marine conservation for 50 years, their role in developing a fully effective marine ecosystems management regime has yet to be fully explored and understood. Copyright © 2016 John Wiley & Sons, Ltd.

The structure of biogenic habitat and epibiotic assemblages associated with the global invasive kelp Undaria pinnatifida in comparison to native macroalgae

Kelp forests dominate temperate and polar rocky coastlines and represent critical marine habitats because they support elevated rates of primary and secondary production and high biodiversity. A major threat to the stability of these ecosystems is the proliferation of non-native species, such as the Japanese kelp Undariapinnatifida (‘Wakame’), which has recently colonised natural habitats in the UK. We quantified the abundance and biomass of U. pinnatifida on a natural rocky reef habitat over 10 months to make comparisons with three native canopy-forming brown algae (Laminaria ochroleuca, Saccharina latissima, and Saccorhiza polyschides). We also examined the biogenic habitat structure provided by, and epibiotic assemblages associated with, U. pinnatifida in comparison to native macroalgae. Surveys conducted within the Plymouth Sound Special Area of Conservation indicated that U. pinnatifida is now a dominant and conspicuous member of kelp-dominated communities on natural substrata. Crucially, U. pinnatifida supported a structurally dissimilar and less diverse epibiotic assemblage than the native perennial kelp species. However, U. pinnatifida-associated assemblages were similar to those associated with Saccorhiza polyschides, which has a similar life history and growth strategy. Our results suggest that a shift towards U. pinnatifida dominated reefs could result in impoverished epibiotic assemblages and lower local biodiversity, although this could be offset, to some extent, by the climate-driven proliferation of L. ochroleuca at the poleward range edge, which provides complex biogenic habitat and harbours relatively high biodiversity. Clearly, greater understanding of the long-term dynamics and competitive interactions between these habitat-forming species is needed to accurately predict future biodiversity patterns.

Responses of estuarine circulation and salinity to the loss of intertidal flats – A modeling study

Intertidal flats in estuaries are coastal wetlands that provide critical marine habitats to support wide ranges of marine species. Over the last century many estuarine systems have experienced significant loss of intertidal flats due to anthropogenic impacts. This paper presents a modeling study conducted to investigate the responses of estuarine hydrodynamics to the loss of intertidal flats in Whidbey Basin of Puget Sound on the northwest coast of North America. Changes in salinity intrusion limits in the estuaries, salinity stratification, and circulation in intertidal flats and estuaries were evaluated by comparing model results under the existing baseline condition and the no-flat condition. Model results showed that loss of intertidal flats results in an increase in salinity intrusion, stronger mixing, and a phase shift in salinity and velocity fields in the bay front areas. Model results also indicated that loss of intertidal flats enhances two-layer circulation, especially the bottom water intrusion. Loss of intertidal flats increases the mean salinity but reduces the salinity range in the subtidal flats over a tidal cycle because of increased mixing. Salinity intrusion limits extend upstream in all three major rivers discharging into Whidbey Basin when no intertidal flats are present. Changes in salinity intrusion and estuarine circulation patterns due to loss of intertidal flats affect the nearshore habitat and water quality in estuaries and potentially increase risk of coastal hazards, such as storm surge and coastal flooding. Lastly, model results suggested the importance of including intertidal flats and the wetting-and-drying process in hydrodynamic simulations when intertidal flats are present in the model domain.

Marine Protected Areas in the Coral Triangle: Progress, Issues, and Options

The six Coral Triangle countries—Indonesia, Malaysia, Papua New Guinea, Philippines, Solomon Islands, and Timor-Leste—each have evolving systems of marine protected areas (MPAs) at the national and local levels. More than 1,900 MPAs covering 200,881 km2 (1.6% of the exclusive economic zone for the region) have been established within these countries over the last 40 years under legal mandates that range from village level traditional law to national legal frameworks that mandate the protection of large areas as MPAs. The focus of protection has been primarily on critical marine habitats and ecosystems, with a strong emphasis on maintaining and improving the status of near-shore fisheries, a primary food and economic resource in the region. This article brings together for the first time a consistent set of current data on MPAs for the six countries and reviews progress toward the establishment of MPAs in these countries with regard to (i) coverage of critical habitat (e.g., 17.8% of the coral reef habitat within the region lies within an MPA), (ii) areas under effective management, and (iii) actions needed to improve the implementation of MPAs as a marine conservation and resource management strategy. The contribution of MPAs to the Coral Triangle MPA System as called for in the Coral Triangle Initiative on Coral Reefs, Fisheries and Food Security Regional Plan of Action is clarified. Options for scaling up existing MPAs to networks of MPAs that are more ecologically linked and integrated with fisheries management and responsive to changing climate through the Coral Triangle MPA System development are discussed. A key point is the need to improve the effectiveness of existing MPAs, and plan in a manner leading to ecosystem-based management.