Last Bite: No Fish Oil No Footnotes

The exponential growth of off-shore mariculture that has occurred worldwide over the last 10 years has raised concern about the impact of the waste produced by this industry on the ecological integrity of the sea bottom. Investigations into this potential source of impact on the biochemistry of the sea floor have provided contrasting results, and no compelling explanations for these discrepancies have been provided to date. To quantify the impact of fish-farm activities on the biochemistry of sediments, we have investigated the quantity and biochemical composition of sediment organic matter in four different regions in the temperate-warm Mediterranean Sea: Akrotiri Bay (Cyprus), Sounion Bay (Greece), Pachino Bay (Italy), and the Gulf of Alicante (Spain). In these four study regions, the concentrations of phytopigments, proteins, carbohydrates, and lipids in the sediments were measured, comparing locations receiving wastes from fish farms to control locations in two different habitats: seagrass beds and soft nonvegetated substrates. Downward fluxes were also measured in all of the regions, up to 200 m from the fish farms, to assess the potential spatial extent of the impact. In all four regions, with the exception of seagrass sediments in Spain, the biochemistry of the sediments showed significant differences between the control and fish-farm locations. However, the variables explaining the differences observed varied among the regions and between habitats, suggesting idiosyncratic effects of fish-farm waste on the biochemistry of sediments. These are possibly related to differences in the local physicochemical variables that could explain a significant proportion of the differences seen between the control and fish-farm locations. Biodeposition derived from the fish farms decreased with increasing distance from the fish-farm cages, but with different patterns in the four regions. Our results indicate that quantitative and qualitative changes in the organic loads of the sediments that arise from intensive aquaculture are dependent upon the ecological context and are not predictable only on the basis of fish-farm attributes and hydrodynamic regimes. Therefore, the siting of fish farms should only be allowed after a case-by-case assessment of the ecological context of the region, especially in terms of the organic matter load and its biochemical composition

Thermal adaptation and physiological responses to environmental stress in tunicates

Understanding the multifaceted nature of environmental fluctuations is crucial to predicting the physiological adjustments utilised by organisms in resisting or adapting to changes over time. Here we investigate the effects of 2 environmental stressors on tunicates, whose fitness can have important repercussions on the quality of habitat. Specifically, we report respiration rate (RR), clearance rate (CR), and assimilation efficiency (AE) of the ascidian Styela plicata in response to a range of temperatures and varying food availability. Temperature-dependent RR was observed only within a portion of the thermal window of the species. Significant differences in clearance rates were detected among organisms fed with varying algal concentrations, while no significant influence of food concentrations on AE was observed. This plasticity of the physiological rates and the development of ubiquitous mechanisms such as temperature-insensitive aerobic metabolism suggest a competitive advantage of this group. Such knowledge may allow for more accurate predictions of the physiological and evolutionary mechanisms driving current and future distribution of this species

The role of juveniles in structuring demersal assemblages in trawled fishing grounds

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High Throughput Protein Similarity Searches in the LIBI Grid Problem Solving Environment

Bioinformatics applications are naturally distributed, due to distribution of involved data sets, experimental data and biological databases. They require high computing power, owing to the large size of data sets and the complexity of basic computations, may access heterogeneous data, where heterogeneity is in data format, access policy, distribution, etc., and require a secure infrastructure, because they could access private data owned by different organizations. The Problem Solving Environment (PSE) is an approach and a technology that can fulfil such bioinformatics requirements. The PSE can be used for the definition and composition of complex applications, hiding programming and configuration details to the user that can concentrate only on the specific problem. Moreover, Grids can be used for building geographically distributed collaborative problem solving environments and Grid aware PSEs can search and use dispersed high performance computing, networking, and data resources. In this work, the PSE solution has been chosen as the integration platform of bioinformatics tools and data sources. In particular an experiment of multiple sequence alignment on large scale, supported by the LIBIPSE, is presented

Thermal and Mechanical Characterization of Yarn Samples from Flemish Tapestry of the Sixteenth Century

We propose a physico-chemical approach for theharacterization of the conservation condition of yarns from a Flemish tapestry of the sixteenth century. The aging effect on the yarns' performance was evaluated by comparison with commercial materials. Water uptake experiments highlighted the aptitude of yarns toward water sorption and their increased hydrophilicity upon aging. Thermogravimetric analysis can be considered a fast approach for the fiber identification and assessment on the material life-time. The dynamic mechanical analysis provided direct evidence on the yarns, conservation state and their performance under different mechanical stresses. The proposed characterization path can be relevant for stating the condition of the tapestry and for designing a conservation protocol for the preservation of the artwork

Concern about the spread of the invader seaweed Caulerpa taxifolia var. distichophylla (Chlorophyta: Caulerpales) towards the West Mediterranean

The new Australian alien seaweed Caulerpa taxifolia var. distichophylla, after being established along the Turkish Mediterranean coast in 2006, was recorded in Southern Sicily in 2007. Since then local fishermen claimed support to counteract the effects of entanglement of large amounts of the alien strain wrack in their trammel nets, causing the gear to become ineffective. The further northward and westward spread of the new alien strain is supposed to be limited by winter temperature. We present novel data confirming that the new alien strain is fully naturalized in Central Mediterranean and is expanding its range beyond such limit (i.e. the 15°C February isotherm), thus becoming potentially able to colonize the western basin. By means of a preliminary estimation of effects on native polychaete assemblages, and considering some peculiarities of Sicily (mostly linked to its geographical position in the Mediterranean Sea), the risk linked to the increasing range of distribution of the invasive algae is highlighted

Site fidelity of Hippocampus guttulatus Cuvier, 1829 at Mar Piccolo of Taranto (Southern Italy; Ionian Sea)

Lack of detailed knowledge on ecological niche, life cycles, spatial distribution, reproductive biology and space use strongly affects the selection of useful tools and measures in the conservation of threatened marine species. Especially for sedentary and slow species, behaviour and movement capacities are supposed to be the most important functional traits. Indeed, behavioural variability concerning available space and the close presence of individuals is considered a crucial trait for the population dynamics assessments, especially when disturbances of various causes are present in the environment. The present study aimed to investigate the site fidelity and degree of movement of Hippocampus guttulatus, an emblematic and threatened Mediterranean seahorse species. With this aim, a number of seahorses were tagged and monitored throughout two years within a limited area of the lagoon of Mar Piccolo of Taranto (Southern Italy). The studied individuals were initially morphometrically measured for size, sex and life-cycle stage and subsequently monitored through repeated four-month surveys each year. Obtained results indicated high site fidelity regardless of habitat type. Movement pattern was in line with the data on congeneric species, although values were slightly higher. The analyses showed differences in movement degree among different sexes and life-cycle stages and indicated greater mobility of adult females compared to males and juveniles. The investigated parameters showed a great variability suggesting that even small-scale environmental factors can influence the species mobility. Finally, a change in the population structure has been observed, with the loss of large individuals in 2016 and reduced recruitment in 2017. These findings indicated the possible presence of stressors that could lead to the alteration of the seahorse population at Mar Piccolo of Taranto

Functional role of biofouling linked to aquaculture facilities in Mediterranean enclosed locations

Biofouling is generally considered a serious threat for human coastal activities such as aquaculture, and the ecological role of fouling organisms associated with fish-farm cages remains one of the most debated topics in the ecological field. However, although biofouling may cause significant problems related to human health, environmental impact and financial losses, in the past decade there has been an increasing interest in developing methods to promote the growth of biofouling on artificial structures as a strategy to mitigate human impacts and reduce the organic enrichment caused by net-cage fish farming. Here we investigated the filtration activity of biofouling assemblages colonizing artificial substrata located within a harbor. The main objective of the study was to determine if and how changes in composition and functioning of biofouling may be affected by hypoxic conditions that periodically occur within the port site selected for this study. To this purpose, artificial panels were used as biofouling collectors and were brought back to the laboratory seasonally where they were divided in 3 subgroups and acclimated at 3 different oxygen levels to mimic the naturally occurring oxygenic conditions. Clearance and respiration rates of each community were measured 6 and 24 h after the beginning of each treatment. Regardless of experimental conditions, performance of the communities was affected by the seasonality and the amount of biomass recruiting on the panels, mainly composed of crustaceans, ascidians, polychaetes, seaweeds and several introduced species. Our study demonstrated that, in particular cases, fouling assemblages linked to aquaculture facilities may contribute to reducing environmental impact and at the same time may serve as input for their re-use in different disciplines

Fish-farm impact on metazoan meiofauna in the Mediterranean Sea: Analysis of regional vs. habitat effects.

The worldwide exponential growth of off-shore mariculture is raising severe concerns about the impacts of this industry on marine habitats and their biodiversity. We investigated the metazoan meiofaunal response to fish-farm impact in four regions of the Mediterranean Sea. Meiofaunal assemblages were investigated in two habitats (seagrass meadows of Posidonia oceanica and non-vegetated soft bottoms) comparing sites receiving faeces and uneaten food pellets from fish farms to control sites. We report here that, consistently across different regions, the meiofaunal abundance typically responded positively to fish-farm effluents. Biodeposition caused also significant changes in assemblage structure and the reduction in the richness of higher meiofaunal taxa, but the multivariate analysis of variance revealed that the effects were region- and habitat-specific. In non-vegetated systems, three of the four regions investigated displayed significant effects of the fish farms on richness of meiofaunal taxa. In vegetated habitats, meiofauna did not respond to biodeposition (except in one region), suggesting that seagrass meadows can mask the effects of fish-farm effluents on benthic biodiversity. We conclude that different indicators of fish-farm impact are needed in vegetated and non-vegetated benthic system