Population structure and dynamics of the invasive Procambarus clarkii (Girard, 1852) in a Tiber river Ramsar site, Central Italy

Procambarus clarkii is a native species of Central America, but strongly invasive in many regions of the world. An investigation on the red swamp crayfish was carried out to obtain more information about its population dynamics in the Tiber River, in Central Italy. A total of 900 individuals, both males and females, were sampled within two different campaigns (2017 and 2019) aimed at collecting biometric data. A strong fishing effort was deployed (more than 100 nets set), to guarantee a large and randomized number of samples. The crayfish populations were grouped into seven different cohorts, according to Bhattacharya's method. The population showed a balanced sex ratio, the average cephalothorax length was 42.52 mm, with the most represented size class between 40-50 mm. K and L∞, as well as the growth parameter index (í˜), the mortality rate (Z), and longevity value (tmax), were calculated. K and í˜ values resulted very high, showing an impressive growth rate in the study area; tmax ranged from 4 to 5 years, L∞ values were lower compared with other studies (58.0-59.0 mm), while Z was very high for this population (4.2-4.5 year). The results revealed that crayfish population dynamics can be complex and vary depending on habitat type, available trophic resource and competition

Insights into different marine aquaculture infrastructures from a life cycle perspective

Aquaculture facilities represent an often-neglected process in environmental impact studies. This study focus on the environmental impact assessment of alternative net materials in Mediterranean marine aquaculture. A Life Cycle Assessment was conducted using primary and secondary data from specific databases and literature. Three baseline scenarios were compared: copper alloy net cages with 100 % of recycled material (CAN100), 75 % of recycled material (CAN75), and polyethylene net (PEN) System boundaries include manufacturing and disposal of cages, nets, and mooring system. The use and emissions of antifouling paints and CAN were considered. Sensitivity analysis of the most impacting sub-processes and Uncertainty analysis were also conducted. The use of CAN is advantageous in terms of environmental impact, but only considering a complete recyclability of the net at the end of its service life. Moreover, when considering a reduced service life of the PEN due to the detrimental effect of biofouling, the advantage of the CAN is even more evident. To counteract the negative effect of biofouling, copper-based antifouling paints are generally used in marine aquaculture. These products are a main environmental hotspot in PEN systems. Therefore, a higher consumption of such products could determine an environmental burden shifting from CAN to PEN ones. So far, CAN are not widespread in the aquaculture industry, mainly due to the high cost of initial investment compared to traditional PEN. Considering operational and environmental advantages, CAN cages could represent an affordable and resilient solution for aquaculture enhancing environmental, economic, and social performances of this industr

Hybridisation between two cyprinid fishes in a novel habitat: genetics, morphology and life-history traits

BACKGROUND: The potential role hybridisation in adaptive radiation and the evolution of new lineages has received much recent attention. Hybridisation between roach (Rutilus rutilus L.) and bream (Abramis brama L.) is well documented throughout Europe, however hybrids in Ireland occur at an unprecedented frequency, often exceeding that of both parental species. Utilising an integrated approach, which incorporates geometric morphometrics, life history and molecular genetic analyses we identify the levels and processes of hybridisation present, while also determining the direction of hybridisation, through the analysis of mitochondrial DNA. RESULTS: The presence of F2 hybrids was found to be unlikely from the studied populations, although significant levels of backcrossing, involving both parental taxa was observed in some lakes. Hybridisation represents a viable conduit for introgression of genes between roach and bream. The vast majority of hybrids in all populations studied exhibited bream mitochondrial DNA, indicating that bream are maternal in the majority of crosses. CONCLUSIONS: The success of roach × bream hybrids in Ireland is not due to a successful self reproducing lineage. The potential causes of widespread hybridisation between both species, along with the considerations regarding the role of hybridisation in evolution and conservation, are also discussed

Organic aquaculture - Weaknesses and opportunities in the sector

The tool offers information about the state of organic aquaculture in Europe, and specifically in Italy. You can also find information about the main certification bodies in Italy, insights from producers, specific breeds for organic aquaculture and information about certain EU regulations

Light and Shape: A Contribution to Demonstrate Morphological Differences in Diurnal and Nocturnal Teleosts

11 pages, 5 figures,1 table.Light intensity is an important environmental factor affecting the structure of fish assemblages during the day–night cycle. Light influences how organisms perceive their environment, modulating their intraspecific and interspecific relationships. The relationship between light intensity variations and biological cycles should be observed at the level of organismal morphology. In this study the relationship between activity rhythms, thus light intensity experienced by fish in the period of major activity and external morphology, have been investigated. The morphological traits of 97 selected fish species were compared in order to determine the existence of a common morphological plan in agreement with their diurnal or nocturnal activity rhythm. Species sorting was performed by maximizing the diversity of activity rhythm, habitat choice, ecology, and trophic habits within the same family, to assess the importance of the day–night cycle on species morphology in relation to other environmental features. The morphological characters selected for the geometric morphometric analysis were body profile and the position of mouth, eye, pelvic, pectoral, dorsal, and caudal fin. The present analysis allowed different consensus forms for nocturnal and for diurnal species to be identified. Two-block Partial Least Squares analysis was then performed for the purpose of modeling the covariation between the form and two important external variables (ecology and activity).Ministero Italiano per le Politiche Agricole e Forestali; Contract grant number: Law 41/82. J. Aguzzi is a postdoctoral fellow (Programa Juan de la Cierva), sponsored by Ministerio de Educacio´n y Cultura, Espa˜na.Peer reviewe

Skin Pigmentation in Gilthead Seabream (Sparus aurata L.) Fed Conventional and Novel Protein Sources in Diets Deprived of Fish Meal

The pattern of yellowish pigmentation of the skin was assessed in gilthead seabream (Sparus aurata) fed for 12 weeks iso-proteic (45%) and iso-lipidic (20%) diets deprived of fish meal and containing either a blend of vegetable protein-rich ingredients or where graded levels of the vegetable protein blend were replaced by insect (Hermetia illucens—10%, 20% or 40%) pupae meal, poultry by-product meal (20%, 30% or 40%), red swamp crayfish meal (10%) and marine microalgae (Tisochrysis lutea and Tetraselmis suecica—10%) dried biomass. Digital images of fish fed diets differing in protein sources were analyzed by means of an automatic and non-invasive image analysis tool, in order to determine the number of yellow pixels and their dispersion on the frontal and lateral sides of the fish. The relationship between the total carotenoid concentration in the diet and the number of yellow pixels was investigated. Test diets differently affected gilthead seabream skin pigmentation both in the forefront and the operculum, due to their carotenoid content. The highest yellow pixels’ number was observed with the diet containing microalgae. Fish fed poultry by-product meal were characterized by the lowest yellow pixels’ number, diets containing insect meal had an intermediate coloring capacity. The vegetable control, the microalgae mix diet and the crayfish diet had significantly higher values of yellow pixels at both inspected skin sites

Is Manila Clam Farming Environmentally Sustainable? A Life Cycle Assessment (LCA) Approach Applied to an Italian Ruditapes philippinarum Hatchery

Italy supplies approximately 96% of EU-farmed Manila clams. Following a reduction in wild seed availability, farmers started to depend on hatchery-produced seed, mainly imported from other countries. Indeed, only one hatchery is currently operating in Italy. This study quantifies the environmental impacts of seed production in this Italian hatchery facility to inform future planning for improving the sustainability of the supply chain. The environmental performance of the Manila clam hatchery was evaluated using the Life Cycle Assessment methodology. A cradle-to-gate analysis was performed, covering the following production phases: (1) microalgae production, (2) broodstock maintenance and conditioning, and (3) larval rearing until marketable size. The functional unit adopted was 1 kg of live clam seed. The main driver of the environmental impacts was electricity consumption, contributing over 80% for all impact categories. Other inputs showed minor contributions to different impact categories, including liquid oxygen, water pumps, and high-density polyethylene. This study highlights that the environmental burden associated with seed production could be reduced by switching to alternative technologies to meet energy needs, such as investments in photovoltaic and wind energy production systems

Is Manila Clam Farming Environmentally Sustainable? A Life Cycle Assessment (LCA) Approach Applied to an Italian <i>Ruditapes philippinarum</i> Hatchery

Italy supplies approximately 96% of EU-farmed Manila clams. Following a reduction in wild seed availability, farmers started to depend on hatchery-produced seed, mainly imported from other countries. Indeed, only one hatchery is currently operating in Italy. This study quantifies the environmental impacts of seed production in this Italian hatchery facility to inform future planning for improving the sustainability of the supply chain. The environmental performance of the Manila clam hatchery was evaluated using the Life Cycle Assessment methodology. A cradle-to-gate analysis was performed, covering the following production phases: (1) microalgae production, (2) broodstock maintenance and conditioning, and (3) larval rearing until marketable size. The functional unit adopted was 1 kg of live clam seed. The main driver of the environmental impacts was electricity consumption, contributing over 80% for all impact categories. Other inputs showed minor contributions to different impact categories, including liquid oxygen, water pumps, and high-density polyethylene. This study highlights that the environmental burden associated with seed production could be reduced by switching to alternative technologies to meet energy needs, such as investments in photovoltaic and wind energy production systems