3,220 research outputs found
Range expansion of an invasive goby in the River Tiber basin (Central Italy): effects on the abundance and shelter occupancy of a congeneric native goby
No full textGiannetto, D./0000-0002-3895-5553;WOS: 000433177000008Padogobius nigricans and Padogobius bonelli are two gobies native to Italy and characterized by an allopatric distribution: P. nigricans is endemic to the Tyrrhenian catchment of central Italy, while P. bonelli is endemic to the Adriatic catchment of Northern Italy. In the past two decades P. bonelli has successfully established in central Italy outside of its original area of distribution, coming into contact with populations of P. nigricans. The superiority of P. bonelli in competition for breeding sites is well documented by laboratory studies; however, little evidence from the field has been provided. In this study, the occurrence and abundance of the two gobies were investigated in the River Tiber basin (central Italy) to assess the impacts of P. bonelli expansion on P. nigricans populations. Moreover, to investigate nest interference by P. bonelli towards P. nigricans, shelter occupancy of the two Italian gobies was investigated in the field with respect to individual density. Sampling was conducted by electrofishing in 77 sites throughout the upper River Tiber basin and nest occupation was analyzed in 8 river stretches. Padogobius bonelli has further expanded its distribution in recent years, following both natural and human-mediated dispersal patterns. It is numerically dominant over P. nigricans and fewer P. nigricans juveniles were found in the invaded than the uninvaded areas. Depending on adult density, P. bonelli can occupy up to 97% of nest sites and can seize a significant percentage of shelters even at low adult abundance. The expansion of P. bonelli into newly colonized areas in recent years has increased concern for the conservation of P. nigricans. In the invaded areas, the survival of P. nigricans populations is mostly through migration of individuals from the uninvaded areas located upstream of weirs, allowing isolated populations of this vulnerable and endangered species to persist
Age Structure and Length-Weight Relationship for Four Species of Aphanius Nardo, 1827 (Actinopterygii: Aphaniidae) Endemic to the Lake District, Central Anatolia, Turkey
No full textGiannetto, D./0000-0002-3895-5553; GUCLU, Salim Serkan/0000-0002-9256-449XWOS: 000474315900008Age structure and length-weight relationship are examined for four species of the genus Aphanius Nardo, 1827 endemic to the Lake District, Central Anatolia, Turkey: A. iconii Aksiray, 1948, A. saldae (Aksiray, 1955), A. sureyanus (Neu, 1937) and A. transgrediens (Ermin, 1946). Specimens were sampled by a shore seine net from Lake Egirdir (A. iconii), Lake Salda (A. saldae), Lake Burdur (A. sureyanus) and Lake Acigol (A. transgrediens) during 2014-2015. A total of 1246 specimens are examined (A. iconii: n=206; A. saldae: n=525; A. sureyanus: n=350; A. transgrediens: n=165). The maximum age for A. iconii, A. saldae and A. sureyanus was 4 years and for A. transgrediens was 5 years. The values of the b parameter of the length-weight equations for A.transgrediens, A. saldae, A. sureyanus and A. iconii populations are 3.027, 2.587, 3.221 and 2.713, respectively. A new maximum total length of 6.1 cm for A. transgrediens is reported.Mehmet Akif Ersoy UniversityMehmet Akif Ersoy University [0205-NAP-13]This research was financially supported by the Mehmet Akif Ersoy University under the Project numbered 0205-NAP-13
Age Structure and Length-Weight Relationship of Non-native Redbelly Tilapia Coptodon zillii (Gervais, 1848) (Cichlidae) in the Pinarbasi Spring Creek (Burdur, Turkey)
No full text7th Workshop of the East-and-South-European-Network-for-Invasive-Alien-Species (ESENIAS) / Scientific Conference on Networking and Regional Cooperation towards Invasive Alien Species Prevention and Management in Europe - MAR 28-30, 2017 - Sofia, BULGARIA0000-0002-3895-5553WOS: 000422703200016The redbelly tilapia, Coptodon zillii, is found in more than 56 countries as a native or introduced fish. In Turkey it is a non-native species and it is present with several acclimatised populations. A population of C. zillii, which almost certainly originated from aquarium industry ponds located in the area of Burdur, is well-established in the Pinarbasi Spring Creek (Burdur, Turkey). This paper aims to study the population structure and some growth properties of C. zillii living in Pmarbast Spring Creek. For this purpose, age and sex composition and length-weight relationships were examined and then compared with those reported for other populations. During the study period (from November 2013 to June 2016), a total of six fish species (C. zillii, Oreochromis niloticus. Oxynoemacheilus anatolicus, Gambusia holbrooki, Carassius gibelio, Clarias sp.) were caught by electrofishing. Among all, C. zillii has the highest abundance (54.77%). Totally, 155 specimens of C. zillii, ranging in size from 2.4 to 20.5 cm in total length and from 0.16 to 166.1 g in total weight, were collected. Of all the examined C. zillii, 80 specimens were immature, 44 were female and 31 were male. The overall sex ratio of females to males was 0.7:1. Ages of captured specimens ranged from 0 to IV. The length-weight relationship for all individuals was described by the parameters a = 0.0078 and b = 3.3543.E & S European Network Invas Alien Species, IBER BAS, DIAS, Republ Bulgaria, Natl Sci Fun
Age and growth of Capoeta erhani Turan, Kottelat and Ekmekci, 2008 from the Seyhan River (Southeast of Turkey)
No full text0000-0002-3895-5553WOS: 000383781700004Capoeta erhani is an endemic species to Southeast of Turkey. To date the information on biology of this species from inland waters of Turkey is very limited. The present study aims to provide the basic age and growth parameters of C. erhani from the middle basin of the Seyhan River. In total, 255 individuals were collected seasonally between October 2013 and September 2014. The overall sex ratio was 3.47: 1 M : F. The total length of the specimens ranged from 10.4 to 33.0 cm and the weight from 9.0 to 360.0 g. The ages of total examined fish ranged from 0 to 5 years. Maximum age was found to be 5 years for both sexes. Length-weight relationship was described as logW = -5.067 + 3.168 logTL (r(2)=0.972). The von Bertalanffy growth parameters were: L-infinity = 32.51 cm; k = 0.400 year(-1); t(0) = -0.930 year for the entire population. Munro's phi prime index in males, females and both sexes was calculated as 6.00, 6.12 and 6.04
Length-weight relationships of two sympatric species (<i>Knipowitschia byblisia</i>Ahnelt, 2011 and<i>K. caunosi</i>Ahnelt, 2011) in Köycegiz Lake, Turkey
No full text0000-0002-3895-5553WOS: 000405112800034This study provides basic information on length-weight relationships for Knipowitschia byblisia Ahnelt, 2011 and Knipowitschia caunosi Ahnelt, 2011, two endemic species of Koycegiz Lake Basin (Southern-West of Turkey). Samplings were carried out seasonally from 2014 to 2015 by means of beach seine nets with mesh sizes from 10 to 35mm. A total of 343 individuals from the two fish species were examined, with more specimens belonging to K.byblisa (90.4%). The total length-weight relationships were calculated as: W=0.0054 TL(3.384)for K.byblisia and W=0.0058 TL(3.417)for K.caunosi, respectively
Fig. 1 in New sighting of the endangered species blackchin guitarfish, Rhinobatos cemiculus, in the South Aegean Sea
No full textFig. 1 Map showing the locations of Rhinobatos cemiculus records in the Aegean Sea (1-Corsini-Foka (2009), 2- Akyol and Capapé (2014), 3-Present study)Published as part of Halit Filiz, Gökçen Bilge, Daniela Giannetto & Sercan Yapı c, 2016, New sighting of the endangered species blackchin guitarfish, Rhinobatos cemiculus, in the South Aegean Sea, pp. 1-4 in Marine Biodiversity Records 9 (13) on page 2, DOI: 10.1186/s41200-016-0009-6, http://zenodo.org/record/26945
Deleuze e l'innocenza del divenire-animale. Per la figurazione di un'etica dell'immanenza assoluta
No full textSaggio contenuto nel volume: AA.VV. Di stelle, atomi e poemi. Verso la physis, a cura di Enrico Giannetto, Aracne, Roma 2018.
Trascrizione ed ampliamento di una conferenza pronunciata in occasione del "Seminario Deleuziano" organizzato dalla prof.ssa Daniela Angelucci e svoltosi il 28 Settembre 2017 presso l'Università degli Studi Roma Tre
Length-Weight Relationship of Knipowitschia ephesi Ahnelt, 1995 (Actinopterygii: Gobiidae) from the Kocagoz Lake, Izmir, Turkey
No full text0000-0002-3895-5553WOS: 000454472300017This study reports the first data on length-weight relationship for the Ephesus dwarf goby Knipowitschia ephesi Ahnelt, 1995, an endemic species of the Aegean Region of Turkey. Fish sampling was carried on from January to November 2015 in the Kocagoz Lake. A total of 61 specimens of K ephesi were collected: 23 females and 38 males, with an overall M : F sex ratio of 1.6 : 1.0. Their size ranged from 1.73 to 3.40 cm and a new maximum total length of 3.4 cm was reported for the species. The overall length-weight relationship was: W = 0.0122 TL2.7517. It was W = 0.0141 TL2.5683 for males and W = 0.0064 TL3.3873 for females
Reproductive parameters in native and non-native areas of Padogobius bonelli and comparison with P-nigricans (Actynopterigii, Gobiidae)
No full text0000-0002-3895-5553WOS: 000382045600013The introduced goby Padogobius bonelli has established abundant populations in the River Tiber basin (Central Italy) and its expansion coincided with the decrease of the endemic P. nigricans. P. bonelli exhibits a more aggressive behaviour than P. nigricans, but other biological attributes may advance its colonization success. To test this hypothesis, some reproductive parameters (gonado-somatic index, age at maturity, egg size, absolute and relative fecundity) of a long-time established non-native population of P. bonelli were analysed and compared to a population from the native area as well as to those of P. nigricans inhabiting the same river. As a result, no differences between non-native and native populations of P. bonelli were observed. On the contrary, non-native P. bonelli showed higher values of gonado-somatic index for both sexes, a more protracted spawning season and produced a greater number of eggs than P. nigricans. These results indicated a greater reproductive output of P. bonelli that can enhance its invasion process and favour the expansion outside of its native range, causing further decline of P. nigricans populations
Feeding ecology of Padogobius nigricans (Canestrini, 1867) and P. bonelli (Bonaparte, 1846) in Aggia River (Umbria, Italy) and their diet overlap
No full textThe Arno goby Padogobius nigricans is
an endemic species to Central Italy. The populations
of this species are in sharp decline due to habitat
modifications and potentially competition with Padanian
goby Padogobius bonelli, an endemic species to
Northern Italy, introduced in some watercourses of
Central Italy. The purposes of this paper were to
analyze dietary composition of the two species,
determine the degree of overlap in their diets and
investigate the feeding ecology of P. nigricans in
terms of absence and presence of the alien species.
Specimens were collected from the Aggia River, a
tributary of Tiber River. Gut contents were analyzed
and prey items were identified to the lowest recognizable
taxa and counted. All the obtained results showed
that P. nigricans and P. bonelli in the Aggia River
share a similar diet. Both species fed extensively on
Chironomids and no statistically significant ontogenetic
changes in feeding habits were found. A high
degree of diet overlap was observed. Diet of P. nigricans
and P. bonelli also included fish and where the
species live in syntopy, individuals belonging to
Padogobius genus were found in stomach, suggesting
that mutual predation may occur
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