16 research outputs found
Sound production in the Ponto-Caspian goby (Neogobius fluviatilis (Pallas, 1814)) and its acoustic affinity with mediterranean species
Cilj provedenog istraživanja bio je opisati vokalni repertoar ponto-kaspijskog rijeÄnog glavoÄiÄa (Neogobius fluviatilis) te usporediti njegova akustiÄna svojstva s vokalnim mediteranskim vrstama iz Gobius grupe. Produkcija zvuka bila je inducirana ātestom uljeza. Istražili smo 5 akustiÄnih svojstva za 13 jedinki. Vokalni repertoar rijeÄnog glavoÄiÄa sastoji se od niza kratkih zvukova produciranih tijekom agresivnih i reproduktivnih interakcija. Zvukovi se sastoje od rapidno ponovljenih pulseva, tipiÄnog tonalnog karaktera. Zvukovi traju oko 200 ms uz prosjeÄnu vrijednost frekvencije od oko 80 Hz. Struktura zvuka se nije mijenjala s obzirom na etoloÅ”ki kontekst, Å”to potvrÄuje njen stereotipski karakter. Podaci o akustiÄnim svojstvima rijeÄnog glavoÄiÄa zajedno sa podacima mediteranskih vrsta, analizirani su pomoÄu Faktorijalne diskriminantne funkcijske analize (DFA) kako bi procijenili u kojoj se mjeri vrste mogu razlikovati s obzirom na njihova akustiÄna svojstava. Rezultati pokazuju kako je stopa ponavljanja pulseva najvažnije svojstvo za razlikovanje vrsta. Smatramo kako upravo ta karakteristika zvuka sadrži informacije o samoj vrsti zbog Äega je kljuÄna pri odreÄivanju filogenetskih odnosa. NaÅ”e istraživanje pokazuje, sukladno molekularnim filogenetskim analizama, da se vrste koje produciraju tonalne zvukove grupiraju zajedno. Rezultati provedenog istraživanja interpretirani su sukladno geoloÅ”kim i filogentskim dogaÄajima za koje se vjeruje da su potaknuli specijaciju europskih glavoÄa.The aim of this study was to describe the vocal repertoire of the Ponto-Caspian goby (Neogobius fluviatilis) and to compare its acoustic properties with those of the other soniferous Mediterranean gobies belonging to the āGobiusā lineage. Sound emission was elicited by means of āintruder testsā. 5 acoustic properties were measured from 13 individuals. The vocal repertoire of the species consisted of sequences of short vocalizations (average 200 ms) showing an average fundamental frequency of about 80 Hz during both agonistic and reproductive intraspecific interactions. Sound properties did not differ between reproductive and the aggressive contexts, and the general structure of sounds were highly stereotyped. Discriminant Function Analysis was performed with individual means of five acoustic properties for seven species to assess how well species could be differentiated on the basis of acoustics, and their degree of affinities. The results suggested that the pulse repetition rate of the sounds was the most important property in differentiating the species. The species producing tonal sounds clustered together in line with the results of recent molecular phylogenic studies. The results were discussed in light of the geological and phylogeographic events believed to have driven the diversification of European gobies
Distribution and morphological variations of invasive macrophytes Elodea nuttallii (Planch.) H. St. John and Elodea canadensis Michx in Croatia
The invasive species Elodea nuttallii was recorded for the first time in the Croatian flora in 2006, in the drainage channels of KopaÄki rit (Baranja). After its establishment, E. nuttallii begins to spread to the eastern and northern part of the drainage channel network from 2006ā2009. High water levels are responsible for the linear spreading direction of E. nuttallii, E. nuttallii and E. canadensis show a wide range of morphological variation, which is characteristic of successful invaders. To show morphological variations of two Elodea species, the most impor tant characters indicated in the literature were measured on 24 fresh collected samples from the seven sites in Croatia. In spite of some overlap in leaf length and width between the two Elodea species, the differences of all morphological traits except internode length are statistically significant. In E. nuttallii leaf width, length and internode length show a higher morphological variability as a result of the higher adaptive strategy to environmental parameters. The most reliable morphological characters distinguishing E. nuttallii and E. canadensis are leaf width 0.5 mm below the tip and the angle at the apex. E. nuttallii can be expected to spread to other areas of Croatia
A REVIEW OF EXTANT CROATIAN FRESHWATER FISH AND LAMPREYS Annotated list and distribution
Prvi je put izraÄen popis hrvatskih slatkovodnih riba. Temelji se na 1360 povijesnih i novijih literaturnih podataka. Na temelju pregleda literature, u Hrvatskoj je, do danas, zabilježeno 137 vrsta riba iz 30 porodica i 75 rodova. Popis je organiziran sistematski i u njemu se navode podaci o rasprostranjenosti slatkovodne ihtiofaune te jesu li vrste endemiÄne, unesene ili prenesene (translocirane).A checklist of the freshwater fish fauna of Croatia is presented for the first time. It is based on 1360 publications of historical and recent data in the literature. According to the literature review, there were 137 fish species in 30 families and 75 genera recorded in Croatia. The checklist is systematicallyarranged and provides distributional data of the freshwater fish fauna as well as whether the species is endemic, introduced or translocated
THREATENED FISHES OF THE WORLD: Orsinogobius croaticus (MrakovÄiÄ, Kerovec, MiÅ”etiÄ and Schneider, 1996) (Teleostei: Gobiidae)
Orsinogobius croaticus je slatkovodna riba s malom i ograniÄenom rasprostranjenosti u Jadranskom bazenu u Hrvatskoj i Bosni i Hercegovini gdje nastanjuje hladne krÅ”ke rijeke i izvore. Glavne prijetnje populacijama su fragmentacija staniÅ”ta, smanjena kakvoÄa staniÅ”ta i unoÅ”enje stranih vrsta. Predlažu se preporuke zaÅ”tite za poboljÅ”anje uÄinkovitog oÄuvanja staniÅ”ta i proÅ”irenje znanja o ovoj vrsti.Orsinogobius croaticus is a freshwater fish with a small and limited distribution range in the Adriatic basin in Croatia and Bosnia-Herzegovina, where it inhabits cold karstic rivers and springs. The main threats to its populations include habitat fragmentation, declining habitat quality and the introduction of alien species. Conservation recommendations are proposed to improve effective habitat preservation and to expand the knowledge about this species
Navike hrvatskih potroÅ”aÄa u online i offline kupovini
kupovina postaje sve prominentnija u svijetu, ali i u Hrvatskoj. Iako se graÄani Hrvatske prilagoÄavaju online kupovini, nije istraženo koje proizvode ili usluge preferiraju kupovati online, a koje offline.
Cilj rada je istražiti navike hrvatskih potroÅ”aÄa pri online i offline kupovini u korelaciji s vrstom proizvoda ili usluga.
NaÄin provoÄenja istraživanja: Na prigodnom uzorku od 108 ispitanika izmeÄu 18 i 60+ godina, primijenjen je online upitnik od 64 Äestice kojem su, uz demografske podatke, dobivene informacije o preferencijama online i offline kupovine obzirom na:
naÄin nabavljanja robe,
uÄestalost nabavljanja robe iz Hrvatskih internet duÄana,
miŔljenje o cijenama proizvoda prilikom kupovine,
važnost doticanja i izboru proizvoda,
procjenu jednostavnosti vraÄanja proizvoda,
usporedbe kvalitete usluge,
praktiÄnost i informiranja prilikom kupovine.
Ovi podaci su se odnosili na osam kategorija proizvoda ili usluga; hrana i bezalkoholna piÄa, odjeÄa i obuÄa, pokuÄstvo, zdravlje, komunikacija i aplikacije, rekreacija i kultura, obrazovanje, restorani i hoteli.
Rezultati: Prema dobivenim rezultatima utvrÄena je statistiÄki znaÄajna korelacija izmeÄu navika online kupovine i dobi ispitanika te da je kronoloÅ”ka dob znaÄajno povezana s edukacijom, ali i sumnjom u sigurnost online kupovine. Dobiveni rezultati su u suprotnosti s rezultatima istraživanja Lyera i Eastmana (2006) koji su utvrdili da su pismenije i tehnoloÅ”ki svjesnije starije osobe motiviranije koristiti internet trgovine.
Sivansan, Monisha et. al., (2017) utvrdili su da žene kupuju viÅ”e online, nego muÅ”karci te da osobe starije od 35 godina rjeÄe kupuju online u usporedbi s mlaÄim stanovniÅ”tvom, Å”to naÅ”im istraživanjem nije potvrÄeno, veÄ dobiveni rezultati sugeriraju da ispitanici pokazuju podjednaku preferenciju online kupovini u odnosu na spol.
ZakljuÄak: Hrvatski kupci naÅ”eg uzorka iskazuju veÄu nesigurnost prema online kupovini s porastom kronoloÅ”ke dobi, žene i muÅ”karci podjednako preferiraju online kupovinu ovisno o financijskim moguÄnostima. Obzirom da je istraživanje provedeno na relativno malom prigodnom uzorku ispitanika, za generaliziranje rezultata, trebalo bi navike prema online ili offline kupovini ispitati opsežnijim istraživanjima na reprezentativnom uzorku.Online shopping is becoming more prominent in the world but in Croatia as well. Even though Croatians are adapting to the trend of online shopping, it has not been researched which goods and services they prefer to buy online, and which do they prefer to buy offline.
The aim of the paper is to research Croatian consumer habits when buying online and offline in correlation with the type of product or service.
Procedure: On a suitable sample of 108 examinees between the ages of 18 and 60+, an online questioner was used with 64 particles where, with the demographic data, information was acquired concerning the preferences of online and offline shopping with regards to:
The way goods are bought,
The frequency of bought goods from Croatian internet stores,
Thoughts about product pricing when shopping
Importance of touch and product diversity
Assessing the ease of returning a product
Comparing product and service quality
The practicality of being informed and shopping
This data referred to the eight product or service categories; food and non-alcoholic drinks, clothes and footwear, household items, health, communications and application, recreation and culture, education, restaurants and hotels.
Results: From the given results a statistically significant correlation was found between the habits of online shopping and age. This also indicated that the chronological age was significantly connected with education but also suspicion concerning online purchases. The results are different to what Lyera and Eastman (2006) found which was that more literate and technology aware older people tend to use online shops more.
Sivansan, Monisha et. al. (2017) have found out that women buy more than men online and also that people older than 35 years of age buy items online more rarely compared to younger people which is not the case in our research data which suggests
iv
that there are no gender differences concerning online shopping habits.
Conclusion: Croatian customers from our sample show greater insecurity towards online shopping as age increases, men and women have the same preference towards online shopping depending on their financial status.
Since the research was done on a relatively small sample, in order to generalize the results further research needs to be done on a bigger sample
Acoustic properties and phylogenetic relationships of gobies from the family Gobiidae (Teleostei; Gobiiformes)
GlavoÄi su najbrojnijih skupina riba zrakoperki. TakoÄer, oni su jedna od akustiÄki najistraživanijih skupina zrakoperki danaÅ”njice, sa 23 poznate vrste koje se glasaju. U sklopu ove disertacije, u Äetiri znanstvene publikacije prvi je put istražena, upotrebom bioakustiÄkih metoda i analiza, sposobnost stvaranja zvukova i vokalni repertoar glavoÄa linije Gobius Neogobius melanostomus, Neogobius fluviatilis i Ponticola kessleri, kao i Perccottus glenii (Odontobutidae). Nadalje, ovom su disertacijom istražene anatomske strukture ukljuÄene u proces produkcije zvukova kod rotana, a rezultati su pokazali kako se mehanizam najvjerojatnije temelji na kontrakcijama kranijalno-pektoralnih miÅ”iÄa. Upotrebom molekularnih analiza koje ukljuÄuju metode filogenetske rekonstrukcije s mitohondrijskim i jezgrenim genetiÄkim biljezima, rekonstruirani su odnosi vokalnih glavoÄa linije Gobius te istražena korelacija izmeÄu genetiÄke i akustiÄke divergencije. Rezultati ove disertacije naglaÅ”avaju kako su zvukovi glavoÄa specifiÄni za pojedinu vrstu, dok njihova interspecijska akustiÄka divergencija prati genetiÄku, Å”to pokazuje kako evolucija zvukova i genotipova prati isti obrazac.Gobies are the most numerous fish group. They are also one of the most investigated acoustic cluster of actinopterygian fish nowadays, with 23 species vocally tested. In this dissertation, represented through four scientific publications, the acoustic communication and vocal repertoire was investigated in Gobius-lineage gobies Neogobius melanostomus, Neogobius fluviatilis and Ponticola kessleri, as well as in Perccottus glenii (Odontobutidae), using standardized bioacoustic methods and analyses. The presented dissertation investigated the anatomical structures involved in the sound production, and the conducted analyses indicate that the sonic mechanism could be based on the contractions of cranio-pectoral muscles. By using phylogenetic analyses with a multilocus approach, we reconstructed the interspecific relationships between vocal gobies from Gobius-lineage and correlated the acoustic and genetic divergences. Results of this dissertation emphasize that goby sounds are truly species-specific, while their interspecific acoustic divergence follows the genotypic divergence, which could indicate that acoustic signals in gobies from Gobius-lineage carry phylogenetic signal
Acoustic properties and phylogenetic relationships of gobies from the family Gobiidae (Teleostei; Gobiiformes)
GlavoÄi su najbrojnijih skupina riba zrakoperki. TakoÄer, oni su jedna od akustiÄki najistraživanijih skupina zrakoperki danaÅ”njice, sa 23 poznate vrste koje se glasaju. U sklopu ove disertacije, u Äetiri znanstvene publikacije prvi je put istražena, upotrebom bioakustiÄkih metoda i analiza, sposobnost stvaranja zvukova i vokalni repertoar glavoÄa linije Gobius Neogobius melanostomus, Neogobius fluviatilis i Ponticola kessleri, kao i Perccottus glenii (Odontobutidae). Nadalje, ovom su disertacijom istražene anatomske strukture ukljuÄene u proces produkcije zvukova kod rotana, a rezultati su pokazali kako se mehanizam najvjerojatnije temelji na kontrakcijama kranijalno-pektoralnih miÅ”iÄa. Upotrebom molekularnih analiza koje ukljuÄuju metode filogenetske rekonstrukcije s mitohondrijskim i jezgrenim genetiÄkim biljezima, rekonstruirani su odnosi vokalnih glavoÄa linije Gobius te istražena korelacija izmeÄu genetiÄke i akustiÄke divergencije. Rezultati ove disertacije naglaÅ”avaju kako su zvukovi glavoÄa specifiÄni za pojedinu vrstu, dok njihova interspecijska akustiÄka divergencija prati genetiÄku, Å”to pokazuje kako evolucija zvukova i genotipova prati isti obrazac.Gobies are the most numerous fish group. They are also one of the most investigated acoustic cluster of actinopterygian fish nowadays, with 23 species vocally tested. In this dissertation, represented through four scientific publications, the acoustic communication and vocal repertoire was investigated in Gobius-lineage gobies Neogobius melanostomus, Neogobius fluviatilis and Ponticola kessleri, as well as in Perccottus glenii (Odontobutidae), using standardized bioacoustic methods and analyses. The presented dissertation investigated the anatomical structures involved in the sound production, and the conducted analyses indicate that the sonic mechanism could be based on the contractions of cranio-pectoral muscles. By using phylogenetic analyses with a multilocus approach, we reconstructed the interspecific relationships between vocal gobies from Gobius-lineage and correlated the acoustic and genetic divergences. Results of this dissertation emphasize that goby sounds are truly species-specific, while their interspecific acoustic divergence follows the genotypic divergence, which could indicate that acoustic signals in gobies from Gobius-lineage carry phylogenetic signal
Acoustic properties and phylogenetic relationships of gobies from the family Gobiidae (Teleostei; Gobiiformes)
GlavoÄi su najbrojnijih skupina riba zrakoperki. TakoÄer, oni su jedna od akustiÄki najistraživanijih skupina zrakoperki danaÅ”njice, sa 23 poznate vrste koje se glasaju. U sklopu ove disertacije, u Äetiri znanstvene publikacije prvi je put istražena, upotrebom bioakustiÄkih metoda i analiza, sposobnost stvaranja zvukova i vokalni repertoar glavoÄa linije Gobius Neogobius melanostomus, Neogobius fluviatilis i Ponticola kessleri, kao i Perccottus glenii (Odontobutidae). Nadalje, ovom su disertacijom istražene anatomske strukture ukljuÄene u proces produkcije zvukova kod rotana, a rezultati su pokazali kako se mehanizam najvjerojatnije temelji na kontrakcijama kranijalno-pektoralnih miÅ”iÄa. Upotrebom molekularnih analiza koje ukljuÄuju metode filogenetske rekonstrukcije s mitohondrijskim i jezgrenim genetiÄkim biljezima, rekonstruirani su odnosi vokalnih glavoÄa linije Gobius te istražena korelacija izmeÄu genetiÄke i akustiÄke divergencije. Rezultati ove disertacije naglaÅ”avaju kako su zvukovi glavoÄa specifiÄni za pojedinu vrstu, dok njihova interspecijska akustiÄka divergencija prati genetiÄku, Å”to pokazuje kako evolucija zvukova i genotipova prati isti obrazac.Gobies are the most numerous fish group. They are also one of the most investigated acoustic cluster of actinopterygian fish nowadays, with 23 species vocally tested. In this dissertation, represented through four scientific publications, the acoustic communication and vocal repertoire was investigated in Gobius-lineage gobies Neogobius melanostomus, Neogobius fluviatilis and Ponticola kessleri, as well as in Perccottus glenii (Odontobutidae), using standardized bioacoustic methods and analyses. The presented dissertation investigated the anatomical structures involved in the sound production, and the conducted analyses indicate that the sonic mechanism could be based on the contractions of cranio-pectoral muscles. By using phylogenetic analyses with a multilocus approach, we reconstructed the interspecific relationships between vocal gobies from Gobius-lineage and correlated the acoustic and genetic divergences. Results of this dissertation emphasize that goby sounds are truly species-specific, while their interspecific acoustic divergence follows the genotypic divergence, which could indicate that acoustic signals in gobies from Gobius-lineage carry phylogenetic signal
Early Development of the Endemic Delminichthys krbavensis (Leuciscidae, Cypriniformes) from a Karstic Field in Croatia
This is the first report of the early development for the endemic Krbava minnow Delminichthys krbavensis from a karstic field in Croatia, and the first report of any species of the genus Delminichthys. The description is based on basic morphometric measures and meristic counts during a 48-day observation of embryos and larvae acquired from successful spawning and rearing in an aquarium. The mean total length of larvae at the time of hatching was 3.12 mm. Mouth opening and independent feeding and intestinal function were observed after day 11 post-hatching (PH) at which time the yolk sac was completely absorbed in all individuals. Flexion of the urostyle began after day 18 PH and was completed by day 23 PH. Pectoral fins developed on day 7 PH, pelvic fins begin to develop by day 44 PH and the formation of caudal, dorsal and anal fin was complete by day 48 PH, when individuals presented the full set of soft rays. Understanding its early development is particularly valuable in assessing the environmental impacts on this endangered species and is essential for its effective monitoring and conservation
A Review of Extant Croatian Freshwater Fish and Lampreys
A checklist of the freshwater fish fauna of Croatia is presented for the first time. It is based on 1360 publications of historical and recent data in the literature. According to the literature review, there were 137 fish species in 30 families and 75 genera recorded in Croatia. The checklist is systematically arranged and provides distributional data of the freshwater fish fauna as well as whether the species is endemic, introduced or translocated