Feeding behaviour of larval European sea bass (Dicentrarchus labrax L.) in relation to temperature and prey density

The feeding behaviour of larval European sea bass (Dicentrarchus labrax, L.) was analysed in relation to temperature and prey density under controlled laboratory conditions with the aim to assess the ability of larval fish to change the feeding tactic as a response to environmental changes. Larvae were acclimated for 20 days at three different temperatures (19, 22 and 26°C), and their feeding behaviour was then video-recorded in experimental trials, at two prey densities, consisting of swarms of 400/l and 1440/l Artemia nauplii. Results showed that there was a significant effect of the interaction between temperature and prey density on the proportion of swimming activity that was reduced at the high temperature-high prey density combination. This suggested a switching in the larval feeding behaviour from an active to an ambush tactic, when the temperature reached 26°C and the prey density was 1440 /l Artemia nauplii. These results are consistent with the current literature on fish larval behaviour in showing that the foraging tactic can be modulated by the interaction of different abiotic and biotic factors characterising the rearing environment

Waste from clam harvesting: a resource for environmental engineering in the Venice lagoon.

Clams harvesting has been widespread in the Venice lagoon since Ruditapes philippinarum introduction in 1983. Operations involved in this kind of activity include a sieving phase: operators pick out clams of commercial interest by using manual or mechanical tools. During this phase they obtain a waste that is usually discarded in lagoon. The Institution responsible of fisheries resources supervision in the Venice lagoon highlighted a management problem related to this kind of waste, that is mostly composed by shells, wood, sediment and different kind of inert materials: in the long term it can accumulate in specific areas covering the seabed and leading to an ecological quality decrease and, consequently, to a lower productivity. So it is necessary to define a strategy in order to collect this material and to avoid the need for its disposal: we took into account the possibility to use it as a filler, in total or partial replacement of the material currently used, for manufactured devices such as gabions and submerged barriers to be used for banks protection and consolidation in the Venice lagoon as well as for beaches protection from erosion. In order to do this, we worked in two directions: on the one hand we evaluated the scientific and technical devices feasibility and on the other hand we considered logistical and organisational aspects related to the project. For this reason we related to stakeholders and to local Authorities to better comprehend their issues, and find possible solutions and policies: in particular we were able to define quantities involved, collection, transport and storage strategies, operative problems related to different phases. This effort made possible the definition of a more effective solution: we were able to integrate ecological and technical issues with logistical and social aspects in order to define a holistic management strategy

The relationships between temperature changes and reproductive investment in the grass goby Zosterisessor ophiocephalus (Pallas, 1811)

OBJECTIVES: ANTXR2 variants have been associated with ankylosing spondylitis (AS) in two previous genome-wide association studies (GWAS) (p∼9×10(-8)). However, a genome-wide significant association (p<5×10(-8)) was not observed. We conducted a more comprehensive analysis of ANTXR2 in an independent UK sample to confirm and refine this association. METHODS: A replication study was carried out with 2978 cases and 8365 controls. Then, these were combined with non-overlapping samples from the two previous GWAS in a meta-analysis. Human leukocyte antigen (HLA)-B27 stratification was also performed to test for ANTXR2-HLA-B27 interaction. RESULTS: Out of nine single nucleotide polymorphisms (SNP) in the study, five SNPs were nominally associated (p<0.05) with AS in the replication dataset. In the meta-analysis, eight SNPs showed evidence of association, the strongest being with rs12504282 (OR=0.88, p=6.7×10(-9)). Seven of these SNPs showed evidence for association in the HLA-B27-positive subgroup, but none was associated with HLA-B27-negative AS. However, no statistically significant interaction was detected between HLA-B27 and ANTXR2 variants. CONCLUSIONS: ANTXR2 variants are clearly associated with AS. The top SNPs from two previous GWAS (rs4333130 and rs4389526) and this study (rs12504282) are in strong linkage disequilibrium (r(2)≥0.76). All are located near a putative regulatory region. Further studies are required to clarify the role played by these ANTXR2 variants in AS

The relationships between temperature changes and reproductive investment in a Mediterranean Goby: insights for the assessment of climate change effects

The relationships between changes in water temperature and the timing and level of reproductive investment were investigated in an estuarine fish, inhabiting the Venice lagoon: the grass goby Zosterisessor ophiocephalus. A time series of the mean monthly values of gonado-somatic index was coupled with thermal profiles of lagoon water temperatures over 14 years, from 1997 to 2010. Results showed that the reproductive investment was positively affected by water temperature changes, both in terms of monthly thermal anomalies and cumulative degree days. A predictive model was also developed to assess the temporal shift of reproductive peaks as a response to inter-annual thermal fluctuations. This model allowed the detection of deviations from the median level, indicating that during warmer years, the reproductive peak tended to occur earlier than during colder years. The model is therefore proposed as a tool to predict anticipated consequences of climate change on fish phenology in transitional waters, regarding recurrent biological phenomena, such as reproduction and recruitment