Cascaded neural networks improving fish species prediction accuracy: the role of the biotic information

Species distribution is the result of complex interactions that involve environmental parameters as well as biotic factors. However, methodological approaches that consider the use of biotic variables during the prediction process are still largely lacking. Here, a cascaded Artifcial Neural Networks (ANN) approach is proposed in order to increase the accuracy of fsh species occurrence estimates and a case study for Leucos aulain NE Italy is presented as a demonstration case. Potentially useful biotic information (i.e. occurrence of other species) was selected by means of tetrachoric correlation analysis and on the basis of the improvements it allowed to obtain relative to models based on environmental variables only. The prediction accuracy of the L. aulamodel based on environmental variables only was improved by the addition of occurrence data for A. arborellaand S. erythrophthalmus. While biotic information was needed to train the ANNs, the fnal cascaded ANN model was able to predict L. aula better than a conventional ANN using environmental variables only as inputs. Results highlighted that biotic information provided by occurrence estimates for non-target species whose distribution can be more easily and accurately modeled may play a very useful role, providing additional predictive variables to target species distribution models

Phylogeography of Sarmarutilus rubilio (Cypriniformes: Leuciscidae): Complex Genetic Structure, Clues to a New Cryptic Species and Further Insights into Roaches Phylogeny

Italy hosts a large number of endemic freshwater fish species due to complex geological events which promoted genetic differentiation and allopatric speciation. Among them, the South European roach Sarmarutilus rubilio inhabits various freshwater environments in three different ichthyogeographic districts. We investigated the genetic diversity of S. rubilio using two different mitochondrial markers (COI and CR), aiming to define its relationship with other similar taxa from the Balkan area and, from a phylogeographic perspective, test the effects of past hydrogeological dynamics of Italian river basins on its genetic structure and demographic history. Our analysis highlighted a marked genetic divergence between S. rubilio and all other roach species and, among Italian samples, revealed the existence of three deeply divergent geographic haplogroups, named A, B and C. Haplogroup C likely corresponds to a new putative cryptic species and is located at the northern border of the South European roach range; haplogroup B is restricted to Southern Italy; and haplogroup A is widespread across the entire range and in some sites it is in co-occurrence with C or B. Their origin is probably related to the tectonic uplifting of the Apuan Alps in the north and of the Colli Albani Volcano in the south during the Pleistocene, which promoted isolation and vicariance followed by secondary contacts

Trophic Requirements of the Sea Urchin Paracentrotus lividus Varies at Different Life Stages: Comprehension of Species Ecology and Implications for Effective Feeding Formulations

Investigations on trophic requirements of different life cycle stages of Paracentrotus lividus are crucial for the comprehension of species ecology and for its artificial rearing. The future success of echinoculture depends heavily on the development of suitable and cost-effective diets that are specifically designed to maximize somatic growth during the early life stages and gonadal production in the later stages. In this context, a considerable number of studies have recommended animal sources as supplements in sea urchin diets. However, with the exception of Fernandez and Boudouresque (2000), no studies have investigated the dietary requirements over the different life stages of the sea urchin. In the present study, the growth and nutrition of three life stages of P. lividus (juveniles: 15-25 mm; subadults: 25-35 mm; adults: 45-55 mm) were analyzed over a 4-month rearing experiment. Three experimental diets, with 0%, 20% and 40% of animal sourced enrichments, were tested in parallel in sea urchin three size classes. The food conversion ratio, somatic and gonadal growth were assessed in each condition in order to evaluate the optimal level of animal-sourced supplements for each life stage. A general growth model covering the full post-metamorphic P. lividus life cycle was defined for each condition. During the juvenile stage P. lividus requires higher animal supply (40%), while a feeding requirement shift takes place toward lower animal supply (20%) in sub-adult and adult stages. Our results evidenced that the progressive increase in size after the metamorphosis led to a consequent variation of trophic requirements and food energy allocation in the sea urchin P. lividus. Macronutrient requirements varied widely during the different life stages, in response to changes in the energy allocation from somatic growth to reproductive investment. This study sheds light on P. lividus trophic ecology, broadening our basic knowledge of the dietary requirements of juveniles, sub-adults and adults as a function of their behavior also in the natural environment

LAKE SHOREZONE FUNCTIONALITY INDEX (SFI) A tool for the definition of ecological quality as indicated by Directive 2000/60/CE

www.appa.provincia.tn.it/binary/pat_appa/pubblicazioni/IFP_Manual_english_ver2.1310115028.pd

THE CHECK-LIST OF THE ITALIAN FRESHWATER FISH FAUNA

The results of the Working Group (WG) on the Systematics and Nomenclature of the italian freshwater fish species established within the A.I.I.A.D. are showed. WG, in about four years of activities, focused on the current taxonomic situation of Italian fish species (Cyclostomes and Bony Fishes), with special reference to the doubtful cases, in the light of the most recent scientific findings. The considerable amount of literature data collected allowed us to clarify the different points of view expressed by the authors who over time contributed to the deepening of knowledge. The Check-list of the Italian freshwater fish fauna could be a useful tool to reach a shared starting point to fill the existing knowledge gaps. Moreover, this need arises from the awareness that the presence of a univocal scientific nomenclature could play a key role in improving the conservation status of the native fish fauna. Finally, we believe that the scientific debate that will hopefully arise, as well as from the activities within WG, also from the presentation of the results to the Association, can represent a useful moment of comparison and cultural growth of all members. The Check-list with the proposed nomenclature for the Italian freshwater fish fauna, the notes drafted for each of the taxa examined (over 80), the sheets with the minutes of each of the discussion sessions carried out, and the archive including all the literature data collected represent useful tools that, through the website (http://www.aiiad.it), will become a shared heritage of the Association

I popolamenti ittici della Riserva Naturale Regionale Monterano

Abstract River fish assemblages, as well as representing an important research topic related to the community of aquatic systems, are also the target of many actions linked to the implementation of EU Directives aimed at the sustainable management of these systems and biodiversity conservation, such as the Water Framework Directive (EC, 2000) and the Habitat Directive (EC, 1992), the latter specifically referring to indigenous fish species and aquatic communities taken as sensitive biotic components to be monitored in order to devise plans for their protection and safeguarding. Ecologically speaking, fish assemblages represent a fundamental biotic component of river systems, where they occupy the highest levels of the trophic networks and exert a strong influence on the structuring and functionality of the ecosystems. Precisely because of their position in the trophic networks and their sensitivity to environmental changes, fish assemblages are often used as bioindicators to evaluate the ecological status of aquatic systems (Tancioni et al., 2005; Scardi et al., 2006). The existing structure of fish assemblages has been affected by a series of remote natural “filters”, such as zoogeographic factors, which have led to the selection of primary endemic taxa (that is, which are confined to fresh or salt waters) as well as by more recent factors of anthropic origin that, after they have become acclimatized, are added to and often compete with similar primary taxa. An analysis of fish assemblages and fish populations, above all in protected fluvial areas, such as the Monterano Regional Nature Reserve (RM), a site of EU interest (Fiume Mignone-Medio Corso IT 6030001), is a fundamental step in the identification of conservation and sustainable management actions regarding original fish biodiversity and that of the river ecosystem concerned. The hydrographic profile of the protected area consists essentially of the middle course of the Mignone River, with its left tributary Torrente Lenta and other secondary water courses. These lotic environments were studied for the purpose of characterizing the fish fauna both in the distant past (Cataudella, 1977; Bianco, 1989), and in more recent times, in order to draw up the Fish Chart for the fish fauna conservation management plan (Bianco and Santoro, 2004), to prepare the Fish Map (Tancioni and Cataudella, 2009) and the Biodiversity Fish Map of the Province of Rome. During the last two study phases regarding the main stretch of the Mignone and along the Lenta, 8 sampling stations were set up, representing different environmental conditions. At these stations experimental fish catches were performed and the environmental characteristics recorded in order to analyse the composition, abundance and structure of the populations and the fish assemblages in conformity with the ISPRA-MATTM sampling protocol for fish fauna in lotic environments (Scardi and Tancioni, 2007). The experimental catches allowed the identification of 14 fish taxa, 6 of which autochthonous and 8 allochthonous (5 taxa transferred from north Italian river basins and 3 taxa of exotic origin), the latter having been introduced principally in the 1980s. Of the observed taxa, the autochthonous species (chub, S. cephalus, Italian soufie, T. muticellus, Apennine barbel, B. tyberinus, Italian brook goby, G. nigricans, Italian orange-fin roach R. rubilio and eel, A. anguilla) account for 43% of the total. The transferred taxa (north Italian bleack, Alburnus alburnus alborella, Italian orange-fin nase, Chondrostoma genei, Italian red-eye roach, Rutilus erythrophthalmus, Po river goby, Padogobius martensii and Po barbel, Barbus plebejus) represent 36%; the exotic taxa (carp, Cyprinus carpio, goldfish, Carassius auratus and pumpkinseed sunfish, Lepomis gibbosus) make up the remaining 21%. Nevertheless, autochthonous species are more prevalent than allochthonous ones, both in terms of number and weight densities. With reference to the various anthropic pressures exerted on the system (e.g. changes in the hydrological and morphological characteristics caused by the presence of a dam on the main stretch of the Mignone, and by a weir on the final stretch of the Lenta; excessive water withdrawals; pollution of domestic origin) the assemblages appear to have distinct structures. In particular, the “healthier” local assemblages from the conservation point of view seem to be those found upstream from the dams and upstream from the Mignone river weir, as well as in the stretch upstream from the Lenta Torrente weir, where endemic and sub-endemic taxa prevail almost exclusively, as is indicated also in annex II to the Habitat Directive. However, while on the one hand these weirs and barrages have had a positive effect on fauna integrity, as they form an insurmountable barrier for the allochthonous taxa moving towards the upstream sections of the watercourses, on the other they prevent the free movement towards the river of migratory indigenous species like the eel (A. anguilla) which are constrained in the downstream stretches. A. anguilla was also recently included on the IUCN red list as one of the species in serious danger of extinction for which specific conservation and sustainable management plans at both EU and national level are being prepared. As far as the conservation and sustainable management actions regarding fish fauna are concerned, several possible actions have been indentified, to be carried out with both in situ and ex situ approaches: construction of “fish-passages” at the level of the weirs to allow selective eel migration (elvers and glass eels); selective transfer of autochthonous fish species from the less tainted zones to those more heavily colonized by allochthonous taxa; reassessment of minimum instream flow conditions downstream from the weir in order to reduce summer-time concentration of specimens in highly confined areas; launching of allochthonous taxa eradication programmes; launching of programmes to produce authochthonous taxa using ecological techniques in order to ensure, wherever necessary, responsible restocking using selected broodstocks that are ‘certified’ on a genetic, morphological and health basis

I pesci come indicatori di qualità ambientale: indici biotici ed altri approcci.

www.cisba.it/Pesci_Tancioni_Scardi pd