THE INFLUENCE OF WATER MACROPHYTES ON THE QUANTITY OF OXYGEN IN CARP PONDS\u27 WATER

Istraživanja djelovanja zaraštenosti šaranskih ribnjaka emerznim makrofitima provedena su a ribnjacima ribnjačarstva D. Miholjac tijekom Ijetnih mjeseci uzgojne sezone god. 1988. i 1989. Istraživanja su provedena u šest ribnjaka, od kojih se a četiri ribnjaka (1, 2, 3 i 4) uzgajao riblji mlad, a u dva ribnjaka (5 i 6) konzumna riba. Obraštenost pojedinih ribnjaka emerznim makrofitima bila je 40 do 70 % površine ribnjaka, a prevladavala je vrsta Nymphoides peltata. Rezultate istraživanja prikazuju tabl. 3. i 4. te sl. 1. Sadržaj kisika a vodi nezaraštenih površina varirao je unutar amplitude od 2,72 mgl-1 do 11,20 mgl-1, što upućuje na povremenu nepoželjnu razinu s gledišta potreba za normalnom prehranom i rast uzgajanih riba. U dijelovima ribnjaka intenzivno zaraštenim emerznim biljem količina se kisika znatno smanjivala uz varijacije unutar amplitude od 1,28 mgl-1 do 7,84 mgl-1 odnosno a svim ribnjacima bila je od 0,32 do 3,84 mgl-1 (9 - 54 %) niža od količine kisika u vodi slobodnih, nezaraštenih dijelova ribnjaka. Ta je razlika bila i statistički opravdana (P < 0,05). Rezultati ovih istraživanja upućuju na znatan negativni utjecaj emerznih makrofita a šaranskim ribnjacima. Ovisno o intenzitetu obraštenosti ribnjaka, smanjuje se i količina kisika a vodi, što smanjuje mogućnost normalne prehrane riba dodatnom hranom. Nedovoljna količina kisika a vodi rezultira slabijom iskorištenošću dodatne riblje hrane, manjim ukupnim prirastima riba i povećanim hranidbenim koeficijentom. Stoga zaključujemo da je očita važnost suzbijanja prekomjerna razvoja vodnih makrofita, ekološke skupine emerznih biljaka, a šaranskim ribnjacima.Research on the influence of emersed macrophytes in carp ponds in fish-farm D. Miholjac was carried on during the summer months of 1988 and 1989. Six carp ponds were under research: in ponds number 1, 2, 3 and 4, the fingerlings were cultured and in the ponds number 5 and 6, marketable fish. Some ponds had 40 - 70% of their area covered by emerged macrophytes, Nymphoides peltata being the dominant species. The results are presented in tables 3 and 4 and on figure 1. The quantity of oxygen in the water of pond areas without emersed macrophytes varied between 2.72 mgl-1 and 11,20 mgl-1 indicating temporary insufficiency as far as requirements for normal growth were concerned. In extremely overgrown areas of the ponds, the quantity of oxygen decreased significantly varying within an amplitude from 1.28 mgl-1 to 7,84 mgl-1. As opposed to pond areas free of weeds, the quantity of oxygen was 9 - 54% lower (from 0.32 mgl-1 to 3.84 mgl-1) in overgrown parts of pond areas. The fact was even significant statistically (p < 0.05). The results indicate significantly negative influence of emersed macrophytes on the carp ponds. The oxygen level in water becomes lower as the overgrowth of the pond area becomes more extensive. That makes the possibility of otherwise normal fish feeding by additional food less convenient. Without the additional food, total fish mass increments are lower, and the food coefficient becomes higher. All of this shows the importance of reducing the overdevelopment of emersed macrophytes in the carp ponds. Therefore, the uprooting of emersed macrophytes from carp pond areas in of utmost importance

UGROŽENE VRSTE RIBA U SVIJETU: Cobitis jadovaensis Mustafić & Mrakovčić, 2008 (Cyprinidae)

Cobitis jadovaensis is a stenoendemic freshwater fish species distributed only in the River Jadova, a small stream in the karst region of Lika in Croatia. Major threats for this fish species are: extremely limited distribution, water abstraction, introduction of alien fish species and increasing severity of droughts. Recommendations for conservation are: habitat protection, prevention of outspreading of alien species from the River Lika and bans on introduction of newalien fish species.Jadovski vijun je stenoendemska slatkovodna riba rasprostranjena samo u rijeci Jadovi, maloj rijeci u Lici, u Hrvatskoj. Glavni uzroci ugroženosti ove vrste su izrazito usko područje rasprostranjenosti, ekstrakcija vode, česte suše uzrokovane klimatskim promjenama i unos alohtonih vrsta riba. Za očuvanje ove vrste predlaže se zaštita staništa, sprječavanje širenja invazivnih vrsta riba iz rijeke Like te zabrana unosa novih alohtonih vrsta riba

NOVI NALAZI OBRVANA, Aphanius fasciatus (Valenciennes, 1821), U HRVATSKOJ

Two new locations of Mediterranean toothcarp (Aphanius fasciatus) were confirmed along the eastern Adriatic coast: one on the island of Rab and the second near the small village of Zablaće, near Šibenik. At both locations, multiple individuals of both sexes were caught using a small hand net. Total length ranged from 12.4 to 39.4 mm and weight ranged from 0.1 to 0.8 g.Dva nova lokaliteta obrvana (Aphanius fasciatus) potvrđena su na istočnoj obali Jadranskog mora. Prvi je lokalitet na otoku Rabu, a drugi je pokraj sela Zablaće u blizini Šibenika. Na obje lokacije malom ručnom mrežicom zabilježeno je više jedinki oba spola. U radu su prikazane glavne morfometrijske i merističke mjere. Totalna dužina (TL) zabilježenih jedinki obrvana varirala je od 12,4 do 39,4 mm, a masa od 0,1 do 0,8 g

Estructura genética poblacional e historia demográfica de Aphanius fasciatus (Cyprinodontidae: Cyprinodontiformes) en hábitats hipersalinos del Adriático oriental

In order to investigate the phylogeography and population genetic structure of the South European toothcarp (Aphanius fasciatus), we analysed gene sequences of two mitochondrial markers (cytochrome b and mtDNA control region) in samples from eight localities along the eastern Adriatic coast and combined them with sequences from other Mediterranean localities. Since the South European toothcarp primarily inhabits hypersaline water bodies, it is a good model species for understanding patterns of colonization and dispersal of species adapted to variable conditions. The eastern Adriatic populations are separated into two groups of genetically related populations. The Northern group contains the populations from Sečovlje, Pag, Dinjiška, Nin and Pantan, whereas the Southern group contains the populations from Ston, Ulcinj and Narta. The majority of divergence events date back to the Pleistocene epoch and it is likely that sea level changes during glacial cycles played a significant role in shaping the recent genetic structure of this species. Our results imply pronounced intraspecific structuring of this species, whereas great environmental variations resulted in a smaller intrapopulational genetic diversity of A. fasciatus than seen in other Mediterranean fishes.Con el objetivo de analizar la estructura genética y filogeografía de las poblaciones del fartet oriental (Aphanius fasciatus), se analizaron secuencias de genes de dos regiones mitocondriales (citocromo b y región de control del ADNmt) en individuos de ocho localidades a lo largo de la costa oriental del Adriático y de otras localidades mediterráneas. El fartet oriental habita principalmente masas de agua hipersalinas, y es una buena especie modelo para el estudio de los patrones de colonización y dispersión de especies adaptadas a condiciones variables. Los resultados de nuestro estudio muestran que las poblaciones del Adriático oriental se separan en dos grupos genéticamente relacionados. El grupo del Norte contiene las poblaciones de Sečovlje, Pag, Dinjiška, Nin y Pantan, mientras que el grupo del Sur contiene las poblaciones de Ston, Ulcinj y Narta. La mayoría de los eventos de divergencia pudiera ser que se remontaran a la época del Pleistoceno, y es probable que los cambios del nivel del mar durante los ciclos glaciales jugasen un papel importante en la estructura genética reciente de esta especie. Nuestros resultados revelan diferencias intraespecíficas pronunciadas en el fartet oriental, y por otro lado menor diversidad genética intrapoblacional como resultado de grandes variaciones ambientales en comparación con otros estudios de peces del Mediterráneo

PRVI NALAZ KOLJUŠKE (Gasterosteus aculeatus Linneaeus, 1758) U DUNAVSKOM SLIJEVU U HRVATSKOJ

One specimen of three-spined stickleback (Gasterosteus aculeatus) was found in a puddle near the Mura River in October 2014 near the town of Mursko Središće. This is the first record of this species in the Danube Basin of Croatia.Jedna jedinka koljuške (Gasterosteus aculeatus) pronađena je u privremenoj lokvi pokraj rijeke Mure u listopadu 2014. godine pokraj mjesta Mursko Središće. Ovo je prvi nalaz koljuške u dunavskom slijevu u Hrvatskoj

UGROŽENE VRSTE RIBA U SVIJETU: Telestes turskyi (Heckel, 1843) (Cyprinidae)

Tursky dace, Telestes turskyi, is a freshwater species endemic to the Adriatic drainage. This species is found only in two rivers in Croatia, the River Krka and River Čikola, and is protected by Croatian law. Major threats for this species are extremely limited distribution, river regulation, water extraction and pollution. Suggested conservation actions for this species are: habitat protection, bans on regulation and alteration of watercourse and restriction of introduction of alien fish species.Turski klen, Telestes turskyi, je slatkovodna riba endemična za Jadranski slijev. Živi samo u dvije rijeke u Hrvatskoj, rijeci Krki i rijeci Čikoli te je zakonom zaštićena. Glavni uzroci ugroženosti ove vrste su ograničeno područje rasprostranjenosti, regulacije riječnog toka i onečišćenje vode. Za očuvanje ove vrste predlaže se zaštita staništa te zabrana regulacije i promjene vodotoka kao i zabrana unosa alohtonih vrsta

UGROŽENE VRSTE RIBA U SVIJETU: Delminichthys krbavensis (Zupančič & Bogutskaya, 2002) (Cyprinidae)

Krbava minnow, Delminichthys krbavensis is a freshwater fish species endemic to the Adriatic watershed in Croatia. It lives only in karstic springs, streams and subterranean waters in Krbavsko polje. This species is protected by Croatian law and is listed in the IUCN Red List as Critically Endangered (CR). D. krbavensis has very limited distribution which makes it vulnerable to different kinds of threats such as water extraction, exploitation of karstic springs and streams, agricultural pollution, road construction and introduction of nonindigenous fish species. Suggested conservation actions for this species are detailed study of biology, ecology and distribution as well as bans on watercourse regulation and road construction, reduction of pollution and restriction on introductions of nonindigenous fish species. Also, conservation of this species should be ensured through implementation of management and action plans.Krbavski pijor, Delminichthys krbavensis, je slatkovodna riba, endem jadranskog slijeva i hrvatski endem. Živi samo u krškim izvorima, vodotocima i špiljama u Krbavskom polju. Zakonom je zaštićena u Hrvatskoj, a nalazi se i na Crvenom popisu IUCN – a (International Union for Conservation of Nature) kao kritično ugrožena vrsta (CR). Glavni uzroci ugroženosti ove vrste su ograničeno područje rasprostranjenosti, isušivanje i pretjerano iskorištavanje krških vodotoka, zagađenje, gradnja prometnica i unos stranih vrsta riba. Za zaštitu ove vrste predlažu se detaljna istraživanja biologije, ekologije i stanja populacija te zabrana regulacije vodotoka, smanjenje zagađenja, zabrana gradnje i zabrana unosa stranih vrsta. Također, potrebna je izrada menadžment plana i plana upravljanja ovom vrstom