Marine ecosystems all over the globe are facing multiple simultaneous stressors including rapid climatic change and increased resource exploitation, such as fishing, petroleum exploration and shipping. The EU-funded DEVOTES project (DEVelopment Of innovative Tools for understanding marine biodiversity and assessing good Environmental Status) aims to better understand the relationships between pressures from human activities and climatic influences and their effects on marine ecosystems. To achieve these goals, it is necessary among others, to test and validate innovative monitoring tools to improve our understanding of ecosystem and biodiversity changes. This paper outlines the application of a high frequency non-invasive (HFNI) valvometer as a potential tool for long-term marine monitoring and assessments. The principle of the method is based on the regular gaping behavior (closing and opening of the valves) of bivalve molluscs and the fact that physical or chemical stressors disrupt that gaping reference pattern. Bivalve gaping behavior is monitored in the natural environment, remotely, continuously over a time period of years, requirements that must be fulfilled if bivalve behavior is to be a useful biomonitoring tool. Here, we review the literature and highlight potential uses of the HFNI valvometry as a biosensor, to monitor and provide early-warning alerts of changes in water quality, such as global temperature increase, releases of contaminants and toxic algal blooms. Finally, potential relevant applications for monitoring and assessing environmental status of marine waters in the context of the Marine Strategy Framework Directive are identified. Relevant descriptors, criteria, and indicators of Good Environmental Status that might be monitored using the HFNI valvometer are discussed for monitoring bathing beaches and harbors, petroleum installations and aquaculture sites.

The ecology of common snook Centropomus undecimalis in Amatique Bay, a tropical estuary in eastern Guatemala, was investigated and life-history traits were used to conduct a meta-analysis of the species from Florida to Brazil. The reproduction cycle of C. undecimalis in Amatique was strongly related to the precipitation cycle, with a lag of 2 months. Spawning occurred from April to November with a peak spawning after the onset of the summer rains. Protandric sex reversal occurred early in the dry season (December) before somatic recovery from spawning. The growth cycle preceded that of body condition by c. 1 month, and was out of phase with the reproductive cycle. Growth was fast, as many individuals reached >70% of the maximum observed total length (LT , 102 cm) after 3 years. Sex transition occurred within a relatively narrow LT range (70-79 cm), but over a wide range of ages, indicating plasticity in this respect. The meta-analysis indicated a latitudinal-temperature gradient in life-history traits, as well as different seasonal patterns relative to temperature and hydrographical cycles. Centropomus undecimalis from cooler winter waters (e.g. Florida) reach larger maximum LT and LT at sex change, as well as greater gonado-somatic indices and longer life spans. Further, increased fishing mortality results in younger age at sex reversal and male predominance in the populations compared. Recognition of large-scale biogeographic patterns in this important, but little studied, fish species helps in the formulation of management advice in other areas of its occurrence.

Jellyfish blooms have increased in magnitude in several locations around the world, including in fjords. While the factors that promote jellyfish blooms and the impacts of live blooms on marine ecosystems are often investigated, the post-bloom effects from the sinking and accumulation of dead jellyfish at the seafloor remain poorly known. Here, we quantified the effect of jellyfish deposition on short-term benthic carbon cycling dynamics in benthic cores taken from a cold and deep fjord environment. Respiration was measured and 13 C-labeled algae were used as a tracer to quantify how C-flow through the benthic food web was affected over 5 d in the presence and absence of jellyfish carcasses. Benthic respiration rates increased rapidly (within 2 h) in the jellyfish-amended cores, and were significantly higher than cores that were supplied with only labeled phytodetritus between 17 h and 117 h. In the cores that were supplied with only labeled phytodetritus, macrofauna dominated algal-C uptake over the 5 d study. The addition of jellyfish caused a rapid and significant shift in C-uptake dynamics: macrofaunal C-uptake decreased while bacterial C-uptake increased relative to the cores supplied with only phytodetritus. Our results suggest that the addition of jellyfish detritus to the seafloor can rapidly alter benthic biogeochemical cycling, and substantially modify C-flow through benthic communities. If our results are representative for other areas, they suggest that jellyfish blooms may have cascading effects for benthic ecosystem functions and services when blooms senesce, such as enhanced bacterial metabolism and reduced energy transfer to upper trophic levels.

The Barents Sea is among the most productive areas in the world oceans, and its shallow banks exhibit particularly high rates of primary productivity reaching over 300 g C m−2year−1. Our study focused on the Svalbard Bank, an important feeding area for fishes and whales. In order to investigate how benthic community structure and benthic secondary production vary across environmental gradients and through time, we sampled across the bank and compared results with a similar study conducted 85 years ago. Considerable variability in community structure and function across bank corresponded with differences in the physical structure of the habitat, including currents, sedimentation regimes and sediment type, and overlying water masses. Despite an intensive scallop fishery and climatic shifts that have taken place since the last survey in the 1920s, benthic community structure was very similar to that from the previous survey, suggesting strong system resilience. Primary and secondary production over shallow banks plays a large role in the Barents Sea and may act as a carbon subsidy to surrounding fish populations, of which many are of commercial importance.

a b s t r a c tAmong the macro-invertebrates used for the assessment of soft-bottom communities, most polychaetes are classified as tolerant/opportunistic to pollution while amphipods are considered as sensitive. These taxa have been used in several ecological indices, such as the simple abundance ratio between Polychaeta and Amphipoda or the Benthic Opportunist Annelids Amphipods (BO2A) index, to assess the Ecological Quality Status -EcoQs-of soft-bottom communities. In terms of Taxonomic Sufficiency (TS), the polychaete/amphipod ratio (i.e. at the level of the class/order) has been proved to be effective in identifying major changes in benthic communities following disturbances. However, an underlying issue is to assess the acceptable TS limit value needed to state accurately the quality of the benthic environment. We tested three indices using 18 series of observations carried out in five north-eastern Atlantic and Mediterranean zones impacted by oil spills, oil and gas production, brine and urban sewage, harbours and aquaculture farms within impacted and control areas. Similar results to BO2A were obtained when limiting the TS at the level of Polychaete opportunistic families, which required a lower degree of taxonomic expertise, and classifying all amphipods as sensitive taxa. In such a way that the EcoQs given by the BPOFA (Benthic Polychaete Opportunistic Families Amphipods) was very similar to those given by the BO2A (Benthic Opportunistic Annelids Amphipods).