Seagrass ecosystems represent a global marine resource that is declining across its range. To halt degradation and promote recovery over large scales, management requires a radical change in emphasis and application that seeks to enhance seagrass ecosystem resilience. In this review we examine how the resilience of seagrass ecosystems is becoming compromised by a range of local to global stressors, resulting in ecological regime shifts that undermine the long-term viability of these productive ecosystems. To examine regime shifts and the management actions that can influence this phenomenon we present a conceptual model of resilience in seagrass ecosystems. The model is founded on a series of features and modifiers that act as interacting influences upon seagrass ecosystem resilience. Improved understanding and appreciation of the factors and modifiers that govern resilience in seagrass ecosystems can be utilised to support much needed evidence based management of a vital natural resource.

The concept of Ecological Potential was explored using the macrobenthic communities of the Mondego estuary (Portugal). Different scenarios (loss of a primary producer and intertidal habitat, and habitat modification due to hydromorphological changes and continued press perturbation) were tested to predict changes in the biology if hydromorphological pressures could be reversed, assuming that differences with and without the pressure could indicate the potential.Results showed noticeable changes in the system biology in each scenario. The approach followed, indicates that when data sets exist, differences in the measurement of ecological status with and without the hydromorphological change could be a way forward to determine the potential. In the particular case of the Mondego estuary, the South arm (physically unaltered water body) proved to be richer than the North (HMWB). For the Ecological Potential determination, the South arm could thus be used to derive and adjust future reference conditions for the North.

Visual pollution is the visible deterioration and negative aesthetic quality of the landscape. Erosion, marine wrack, litter, sewage, and beach driving are affecting the coastal scenery and are generating a visual pollution problem on the Rabigh coastal area, Kingdom of Saudi Arabia. This work provides the scenic evaluation of 31 coastal sites using the Coastal Scenery Evaluation System (CSES) to determine the current state of this situation and give management inputs. The CSES assesses values from a checklist of 18 physical and 8 human parameters and allows the calculation of a scenic evaluation index (D Value), which classifies coastal sites into five classes: Class I, usually natural areas of top scenic characteristics, to Class V, poor scenic natural areas with a higher impact of human interventions. Along the study area, three sites (9.7 %) appeared in Class II; five (16.1 %) in Class III; 15 (48.4 %) in Class IV, and eight sites (25.8 %) in Class V. Class I sites were not found in the study area. Assessment presented in this work provides a complete overview of the Rabigh coastal scenery and serves as a baseline for implementing management strategies to cope the visual pollution problem.

A ridge-to-reef framework was developed for 26 watersheds around Guam. Dissolved inorganic nitrogen (DIN) data were collected for one year at the base of streams while coral and fish surveys were conducted on adjacent reefs. Two independent analyses revealed a similar 0.10 mg/l DIN threshold beyond which negative impacts to water quality and coral reefs existed. The influence of DIN was next partitioned with respect to a second primary stressor, fishing pressure. While coral diversity was negatively influenced by DIN, the cover of some stress-tolerant corals increased, such as Porites rus, making coral cover alone a poor indicator of watershed pollution. Less intuitive, DIN predicted increased food-fish biomass that was accounted for by generalist herbivores/detritivores, representing homogenized assemblages, while fishing pressure reduced biomass. Our DIN thresholds resonated with a similar study in American Samoa suggesting broader guidance for water quality legislation may be emerging.

Seagrass ecosystems exist throughout Pacific Island Countries and Territories (PICTs). Despite this area covering nearly 8% of the global ocean, information on seagrass distribution, biogeography, and status remains largely absent from the scientific literature. We confirm 16 seagrass species occur across 17 of the 22 PICTs with the highest number in Melanesia, followed by Micronesia and Polynesia respectively. The greatest diversity of seagrass occurs in Papua New Guinea (13 species), and attenuates eastward across the Pacific to two species in French Polynesia. We conservatively estimate seagrass extent to be 1446.2 km², with the greatest extent (84%) in Melanesia. We find seagrass condition in 65% of PICTs increasing or displaying no discernible trend since records began. Marine conservation across the region overwhelmingly focuses on coral reefs, with seagrass ecosystems marginalised in conservation legislation and policy. Traditional knowledge is playing a greater role in managing local seagrass resources and these approaches are having greater success than contemporary conservation approaches. In a world where the future of seagrass ecosystems is looking progressively dire, the Pacific Islands appears as a global bright spot, where pressures remain relatively low and seagrass more resilient.

The present study aimed to develop monitoring methods for shallow water sessile and mobile epifauna with the main focus on enhancing the chance of early detection for new non-indigenous species (NIS) invasions. The field sampling was conducted between June and September in 2012, in the Archipelago Sea (Finland). The tested monitoring methods included baited traps that capture organisms and habitat collectors that provide habitat and refuges for organisms, as well as fouling plates. Catch efficiency of a trap/collector was defined as the number of NIS and all species caught, including their abundances. The American collector with oyster shells (habitat collector) caught the highest number of NIS, and their use is recommended in all places, where oyster shells are easily accessible. Sampling of all habitats of interest between 1 and 2 m depth is recommended with at least three habitat collectors per site.

The present study describes the novel use of fatty acids (FAs) and element profiles of Octopus vulgaris inhabiting three coastal areas in the W-Mediterranean Sea. These populations are exposed to different anthropogenic activities, and were compared at different geographical scales. The FA composition in the mantle of O. vulgaris exhibited significant differences in 22:6 n−3 (DHA) and 22:5 n−3 (EPA) among the sampled populations. The essential microelements Fe, Cu, Zn and Ni, and the non-essential microelements As, Sr, Al and Cd were the main contributors of variability among sampled octopus populations, with some notable differences among tissues. The variations in the FAs and elemental composition in octopus tissues were detected with other populations throughout the species distribution range, which might reflect differences in natural habitats and foraging strategies. Therefore, these may be considered biomarkers as a proxy to distinguish the origin of octopus specimens at different scales.

Understanding population dynamics of established invasive species is important for designing effective management measures and predicting factors such as invasiveness and ecological impact. The kelp Undaria pinnatifida has spread to most temperate regions of the world, however a basic understanding of population dynamics is lacking for many regions. Here, Undaria was monitored for 2 years, at 9 sites, across 3 habitats to investigate habitat-related variation in population structure, reproductive capacity and morphology. Populations on marina pontoons were distinct from those in reef habitats, with extended recruitment periods and higher abundance, biomass, maturation rates and fecundity; potentially driven by lower inter-specific and higher intra-specific competition within marinas. This suggests that artificial habitats are likely to facilitate the spread, proliferation and reproductive fitness of Undaria across its non-native range. More broadly, generalising population dynamics of invasive species across habitat types is problematic, thus adding high complexity to management options.

Tropical sea cucumber fisheries are generally traditional, small-scale, multispecies and poorly managed. Many recent studies have improved our knowledge on the biology and ecology of the commercially important species; the main results are analysed and the remaining gaps discussed. The fisheries and the patterns of trade changes during the last decade are presented from the data available and confirm overexploitation in the traditional Indian Ocean and West Pacific countries and territories. Several Latino-American countries now have active fisheries. Despite the management and conservation issues which have recently received more attention at international, regional and national levels, more measures are still needed at all these levels, to ensure sustainable exploitations of these resources.

Increasing accessibility of coral reefs from the latter third of the 20th century led quickly to recognition of the vulnerability of coral reef communities to a combination of direct and indirect human impacts. Coral reefs are confronted by the stark threats of climate and ocean changes from the increasing number, intensity and forms of human use impacting global and marine systems. Management, particularly of accessible coral reefs, occurs in the context of multiple scale transboundary water column linkages of lifecycle processes and increasing human use of coastal and marine space. Four decades of experience have demonstrated the combined importance of biophysical and socio-economic sciences and sharing knowledge with communities for developing implementing effective management. In the face of environmental and socio-economic change the challenge for science and management is to develop knowledge and management responses that can better understand and increase resilience to improve he outlook for coral reef communities.