Repository of the Department of Marine Studies at the University of Split
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Temporal and spatial distribution of early developmental stages of Sardina pilchardus (Walbaum, 1792) in the Adriatic sea
No full textU ovome radu predstavljeni su rezultati uzorkovanja provedenih tijekom 2023. godine na području Jadranskog mora, s ukupno 67 postaja na kojima su mjereni temperatura, salinitet te abundancija jajašaca i ličinki srdele. Prikazana je prostorna raspodjela podataka, koja pokazuje grupiranje ranih razvojnih stadija srdele na određenim područjima hrvatskog ribolovnog mora. Testirana je korelacija između abiotičkih (temperatura, salinitet) i biotičkih parametara (abundancija ranih razvojnih stadija - jajašaca i ličinki srdele) pomoću linearne regresije i neuronske mreže. Rezultati obiju metoda dokazuju kako ne postoji korelacija između njih, odnosno pokazuje slabu povezanost unutar određenih klasa u neuronskim mrežama s četiri i pet neurona. Objašnjena je svaka primijenjena metoda kao i važnost prilagođavanja načina uzorkovanja i obrade podataka u ovom kao i u budućim sličnim istraživanjima.In this paper, the results of sampling during 2023 research cruise in the Adriatic Sea are presented, covering a total of 67 stations where temperature, salinity, and the abundance of sardine eggs and larvae were measured. The spatial distribution is presented, highlighting the grouping of eggs and larvae in certain areas within the Croatian fishing ground. The correlation between abiotic (temperature, salinity) and biotic (abundance of sardine early life stages - eggs and larvae) parameters was tested using linear regression and neural networks. The results of both methods demonstrate that there is no correlation between them, indicating a weak connection within certain classes in neural networks with four and five neurons. Each applied method is explained, as well as the importance of adjusting the sampling and data processing methods in this, as well as in similar future studies
The impact of shellfish farming on meiofaunal composition
No full textU ovom radu analizirano je 12 uzoraka sedimenta prikupljenih na dvije postaje u blizini Šibenskog mosta kako bi se istražio utjecaj uzgajališta školjkaša na sastav i strukturu meiofaune u sedimentu ispod uzgajališta. Ukupni broj taksonomskih skupina bio je isti na postaji ispod uzgajališta i na referentnoj postaji (15), no brojnost organizama bila je veća na referentnoj postaji (236,3 ± 90,4 jedinki na/10 cm²) u usporedbi s postajom ispod uzgajališta (179 ± 58,1 jedinki na 10 cm²). Oblići su bili dominantna skupina na obje postaje, s nešto većim udjelom na postaji ispod uzgajališta (62,94%) u usporedbi sa referentnom postajom (60,72%). Veslonošci i mnogočetinaši su skupine koje su zabilježene u manjim postocima ispod uzgajališta (10,24% i 6,52%), u usporedbi sa referentnom postajom (12,03% i 6,78%). Vertikalna distribucija organizama pokazala je veći broj organizama u površinskom sloju (0-1 cm) na referentnoj postaji (155,2 ± 102,9 jedinki na 10 cm²), u odnosu na postaju ispod uzgajališta (115,7 ± 76,2 jedinki na 10 cm²). Rezultati dobiveni u ovom diplomskom radu sugeriraju da aktivnosti uzgoja školjkaša mogu utjecati na brojnost i raspodjelu organizama meiofaune u sedimentu ispod uzgajališta.This study analyzed 12 sediment samples collected from two different locations near the Šibenik Bridge to investigate the impact of shellfish farming on the composition and structure of meiofauna. The total number of taxonomic groups was the same at the site below the shellfish farm and at the reference site (15), but the abundance of organisms was higher at the reference site (236.3 ± 90.4 ind. 10 cm²) compared to the site below the farm (179 ± 58.1 individuals per 10 cm²). Nematodes were the dominant group at both sites, with a slightly higher proportion at the site below the farm (62.94%) compared to the reference site (60.72%). Copepods and polychaetes groups were less represented below the farm, with proportions of 10.24% and 6.52%, compared to 12.03% and 6.78% at the reference site. The vertical distribution of organisms showed a higher number of organisms in the surface layer (0-1 cm) at the reference site (155.2 ± 102.9 individuals per 10 cm²) compared to the site below the farm (115.7 ± 76.2 individuals per 10 cm²). These results suggest that shellfish farming may affect the abundance and distribution of meiofauna
Coronary circulation in fish
No full textU ovom završnom radu je opisana važnost koronarne cirkulacije koju nalazimo kod riba. Rad donosi temeljne podatke o funkciji, građi, ulozi i reguliranju koronarne cirkulacije. Rad nudi kratak pregled i opis najvažnijih dijelova krvožilnog sustava. Također, poseban naglasak je stavljen na protok krvi kroz cirkulaciju, dijelovima srca i građi koronarne arterije. Opisani su načini s kojima ribe reguliraju protok krvi kroz krvne žile, djelovanje vanjskih čimbenika (hipoksije i tjelovježbe), te hormonalna regulacija cirkulacije.This paper describes the importance of coronary circulation found in fish. The paper provides basic information on the function, structure, role and regulation of coronary circulation. The paper offers a brief overview and description of the most important parts of the circulatory system. Also, special attention is placed on the circulation of the blood through the circulation, the parts of the heart and the structure of the coronary artery. The work provides information on how fish regulate blood flow through blood vessels, the effect of external factors (hypoxia and exercise), and the hormonal regulation of circulation
The long-term trend of seawater quality on the beaches of the croatian Adriatic coast
No full textObzirom da je zaštita morskog okoliša strateški cilj Republike Hrvatske, postizanje i održavanje visoke kakvoće mora za kupanje neki su od njezinih prioriteta. Praćenje kakvoće mora na plažama sustavno se provodi još od 1989. godine, a od 2009. godine do danas temelji se na kriterijima Uredbe o kakvoći mora za kupanje (NN 73/2008).
Cilj ovog rada je odrediti udio kategorija kakvoće (izvrsna, dobra, zadovoljavajuća i nezadovoljavajuća) u godišnjim i konačnim ocjenama kakvoće mora za kupanje te procijeniti njihov trend u razdoblju od 2009. do 2022. godine po pojedinim priobalnim županijama: Istarskoj, Primorsko-goranskoj, Ličko-senjskoj, Zadarskoj, Šibensko-kninskoj, Splitsko-dalmatinskoj i Dubrovačko-neretvanskoj. Za isto razdoblje utvrđen je položaj koji je Hrvatska zauzela u odnosu na ostale države Europske unije prema rezultatima kakvoće mora za kupanje. Dodatno, u istraživanom 14-godišnjem razdoblju praćene su i varijacije broja lokacija po županiji, na hrvatskoj obali Jadrana. Analiziran je broj pristupa korisnika plaža nacionalnoj bazi podataka o kakvoći mora na plažama, na hrvatskom i engleskom jeziku.
Za analizu stanja korišteni su podaci za pojedinu županiju i godinu, dostupni u nacionalnoj bazi podataka te podaci iz godišnjih europskih izvješća dostupni na web stranici EEA (engl. European Environment Agency). Ocjena kakvoće mora za kupanje temelji se na koncentraciji indikatora fekalnog onečišćenja: Escherichia coli (metoda određivanja modificirana HRN EN ISO 9308-1:2014/A1:2017) i crijevni enterokoki (metoda određivanja HRN EN ISO 7899-2:2000). Dobiveni rezultati opisani su deskriptivnom statistikom (relativnim frekvencijama, aritmetičkom sredinom, rasponom podataka) te grafički. Analiza dostupnih podataka ukazuje na visoku razinu kakvoće mora za kupanje s kontinuiranim trendom povećanja udjela lokacija s izvrsnom ocjenom na razini svih priobalnih županija na hrvatskoj obali Jadrana. Broj lokacija ispitivanja je u stalnom porastu, kao i ukupan broj pristupa mrežnoj aplikaciji. Udio izvrsnih godišnjih ocjena u Hrvatskoj za 12 % je viši od Europske unije. Da bi se održali ovi pozitivni trendovi potrebna su stalna ulaganja u prikupljanje, obradu i odvodnju komunalnih otpadnih i oborinskih voda te kontinuirano unapređenje monitoringa kakvoće mora za kupanje.Considering that the protection of the marine environment is a strategic goal of the Republic of Croatia, achieving and maintaining high quality bathing sea is one of its priorities. The monitoring of sea quality on beaches has been carried out systematically since 1989, and from 2009 to the present, this monitoring has been based on the criteria of the Regulation on Sea Bathing Water Quality (OG 73/2008). The aim of this paper is to determine the share of quality categories (excellent, good, satisfactory, and unsatisfactory) in annual and final quality ratings for bathing sea and to assess their trend in the period from 2009 to 2022 by individual coastal counties: Istria, Primorje-Gorski Kotar, Lika-Senj, Zadar, Šibenik-Knin, Split-Dalmatia, and Dubrovnik-Neretva. In the same period, Croatia's position was determined in relation to other European Union countries according to the results of quality of bathing sea. Additionally, in the investigated 14-year period, variations in the number of locations per county along the Croatian coast of the Adriatic were monitored. The number of accesses by beach users to the national database on sea quality, in Croatian and English, was analysed. Data on bathing sea quality available in the national database for each county and each year, as well as data from the annual European reports and the European Environment Agency (EEA) website, were used to analyse the situation. The bathing sea quality assessment is based on the concentration of fecal pollution indicators: Escherichia coli (determination method modified HRN EN ISO 9308-1:2014/A1:2017) and intestinal enterococci (determination method HRN EN ISO 7899-2:2000). The results obtained are described using descriptive statistics (relative frequencies, arithmetic mean, data range) and are presented graphically. The analysis of the available data indicates a high quality of bathing sea, with a continuous trend of increasing the share of locations with an excellent rating across all coastal counties on the Croatian Adriatic coast. The number of test locations is constantly growing, as is the total number of accesses to the online application. Croatia's share of excellent annual grades is 12% higher than in the European Union. To maintain these positive trends, constant investments in the collection, treatment and drainage of municipal wastewater and stormwater are needed, as well as continuous improvement of the monitoring of the quality of bathing sea
Response of marine organisms to microsymbionts
No full textMorski ekosustavi su složene mreže u kojima organizmi formiraju brojne asocijacije s mikroorganizmima, stvarajući simbiotske odnose koji su ključni za njihov opstanak i evoluciju. Ova teza predstavlja složene interakcije između morskih organizama i njihovih mikrosimbionata, naglašavajući raznolikost tih odnosa, u rasponu od mutualizma do parazitizma. Koncept 'holobionta' naglašava složenu interakciju između domaćina i mikroorganizama te predlaže novi pristup razumijevanju koevolucije i kolektivnih funkcija u morskom životu. Od beskralješnjaka do kralježnjaka, morski organizmi žive u simbiozi s bakterijama, virusima, protistima, arhejama i gljivama. Složenost tih asocijacija ogleda se u odgovorima morskih ekosustava na stresore kao što su klimatske promjene, zakiseljavanje oceana i antropogeni utjecaji, što može dovesti do promjene između stanja simbioze i disbioze. Stresori mogu povećati otpornost nekih vrsta, dok druge čine ranjivima. Mikrosimbionti pružaju esencijalne koristi poput kruženja nutrijenata, zaštite od patogena te potpore za reprodukciju i rast domaćina. Fokusirajući se na adaptivne mehanizme mikrobioma, ova teza raspravlja o adaptivnim strategijama domaćina koje jačaju simbiotska partnerstva. Osim toga, teza ističe važnost holističkog pristupa proučavanju morske biologije koji prepoznaje neodvojivost organizama i njihovih simbionata u morskom okruženju.Marine ecosystems are complex networks in which organisms form numerous associations with microorganisms, creating symbiotic relationships that are crucial for their survival and evolution. This thesis presents the intricate interactions between marine organisms and their microsymbionts, emphasizing the diversity of these relationships, ranging from mutualism to parasitism. The concept of the 'holobiont' emphasizes the complex interaction between host and microorganisms and proposes a new approach to understanding coevolution and collective functions in marine life. From invertebrates to vertebrates, marine organisms live in symbiosis with bacteria, viruses, protists, archaea, and fungi. The complexity of these associations is reflected in the responses of marine ecosystems to stressors such as climate change, ocean acidification, and anthropogenic impacts, which can lead to an alteration between states of symbiosis and dysbiosis. Stressors can enhance the resilience of some species while making others vulnerable. Microsymbionts provide essential benefits such as nutrient cycling, protection from pathogen and support for host reproduction and growth. By focusing on the adaptive mechanisms of the microbiome, this thesis discusses the adaptive strategies of hosts that strengthen symbiotic partnerships. Additionally, the thesis highlights the importance of a holistic approach to the study of marine biology that recognizes the inseparability of organisms and their symbionts in the marine environment
UTJECAJ ACIDIFIKACIJE MORA NA BIOLOŠKE-EKOLOŠKE ZNAČAJKE POPULACIJE KVRGAVOG VOLKA HEXAPLEX TRUNCULUS (LINNAEUS, 1758) IZ MALOSTONSKOG ZALJEVA
No full textThe biological and ecological response of the predatory marine gastropod species Hexaplex trunculus to a range of low pH (pHT 7.95 – 7.22) relevant in the context of ocean acidification was studied. This is the first study on the effects of ocean acidification conducted on a population of a species from the east coast of the Adriatic Sea and the first study on intracapsular development in the class Gastropoda where the parental generation was exposed to a range of low pH in the long-term. The results show that H. trunculus employs a variety of trade-off mechanisms to cope with low pH. Feeding rate and ability to find food were not affected by low pH, although gastropods exposed to low pH took less time to reach food. Acute exposure to low pH had a positive effect on H. trunculus growth rate, but during energy-limiting periods, shell growth was negatively impacted. However, prolonged exposure resulted in acclimatization with no discernible differences among pH conditions. The net calcification rate was negatively affected by low pH for the whole duration of the experiment. H. trunculus managed to maintain the same rate of total body weight over the period of acute exposure, but during the remainder of the period, total body weight decreased with low pH. Soft tissue body weight remained unaffected until the completion of spawning, suggesting a subsequent negative effect. No sex-specific differences were observed in the response to low pH. Female gastropods initially exhibited reduced metabolic rates at low pH, but the balance was restored over time. The pH had no effect on spawning characteristics, but intracapsular development was impaired under certain low pH conditions (pHT < 7.51), impacting post-veliger developmental stages. Acute exposure of spawns to low pH had a negative effect on intracapsular development. Parental exposure generally had a negative effect on intracapsular development, but variability in the response was observed. Negative effects could be partially reversed, as shown by the improved growth of embryos from parents preconditioned to lower pH when transferred to higher pH. This study enhances the understanding of H. trunculus responses to future ocean acidification and emphasizes the complexity of adaptive strategies and the importance of considering individual variability and parental influence while assessing species sensitivity.Radi očekivanih globalnih promjena kiselosti mora istraživan je biološki i ekološki odgovor predatorskog puža Hexaplex trunculus na pH vrijednosti u rasponu od 7,95 do 7,22. Ovo je prvo istraživanje o utjecaju nižeg pH provedeno na nekoj istočnojadranskoj populaciji te prvo istraživanje intrakapsularnog razvoja predstavnika razreda Gastropoda u kojem je roditeljska generacija dugotrajno izložena rasponu vrijednosti pH. Rezultati pokazuju da H. trunculus koristi različite mehanizme prilagodbe sniženom pH mora. Vrijednosti pH nisu imale utjecaja na tjednu stopu prehrane i sposobnost pronalaska hrane, iako je jedinkama iz okoliša s nižim pH trebalo manje vremena za pronalazak hrane. Akutna izloženost niskom pH utjecala je na brži rast duljine kućice, dok je pri nižim temperaturama i smanjenoj metaboličkoj aktivnosti stopa rasta kućice bila smanjena u sniženom pH. Međutim, dugotrajna izloženost nije rezultirala razlikom u duljini kućice između jedinki iz različitih pH uvjeta. Snižen pH je negativno utjecao na neto stopu kalcifikacije tijekom eksperimenta. Tijekom razdoblja akutne izloženosti stopa rasta ukupne mase H. trunculus nije se mijenjala, no tijekom trajanja eksperimenta stopa rasta se proporcionalno smanjivala snižavanjem vrijednosti pH. Stopa rasta mase mekog tkiva nije se mijenjala do završetka mriješćenja, nakon čega se masa mekog tkiva u uvjetima niže pH vrijednosti smanjivala. Nije zabilježena razlika mjerenih značajki između mužjaka i ženki. Opažena je smanjena stopa respiracije ženki za vrijeme akutne izloženosti pri niskom pH, ali nakon dugotrajnije izloženosti nije bilo razlike u stopi respiracije između ženki iz različitih pH uvjeta. Vrijednost pH nije imala utjecaja na mriješćenje i značajke mrijesta, ali je opažena razlika u intrakapsularnom razvoju pri pojedinim vrijednostima pH (pHT < 7,51), te negativni utjecaj na razvojne faze nakon stadija veliger ličinke. Akutna izloženost mrijesta niskom pH imala je negativan učinak na intrakapsularni razvoj. Izloženost roditelja nižim vrijednostima pH rezultirala je manjim rastom tijekom intrakapsularnog razvoja. Bolji rast ličinki nakon prebacivanja u više vrijednosti pH nakon dugotrajne izloženosti njihovih roditelja nižim vrijednostima, ukazuje na mogućnost smanjivanja negativnih učinaka Rezultati ovog istraživanja doprinose razumijevanju odgovora na očekivanu acidifikaciju mora te ukazuju na složenost strategija prilagodbe
Biodiversity of shellfish in Natura 2000 areas
No full textU ovom radu je prikazano istraživanje zajednice školjkaša na kolektorima ličinki školjkaša postavljenim na dva područja ekološke mreže Natura 2000, Pantan (HR3000430) i ušće Cetine (HR3000126). Kolektori su postavljeni s ciljem prikupljanja ličinki endemske, dugoživuće, kritično ugrožene i strogo zaštićene vrste školjkaša u Mediteranu, periske Pinna nobilis, Linnaeus 1758 dok je cilj ovog rada bio prikupljanje podataka o biološkoj raznolikosti školjkaša na kolektorima uključujući determinaciju invazivnih i endemskih vrsta morskih organizama. Tijekom analize obraštajne zajednice s kolektora ličinki školjkaša determinirano je ukupno 19 vrsta školjkaša iz 9 porodica. Tijekom laboratorijske analize nisu determinirane invazivne vrste školjkaša međutim determinirana je invazivna vrsta mješčićnice Styela plicata.The paper presents the investigation of the bivalve community on bivalve larvae collectors placed in two areas of the Natura 2000 ecological network, the Pantan (HR3000430) and the Cetina estuary (HR3000126). The collectors were installed with the aim of collecting the larvae of an endemic, long-lived, critically endangered and strictly protected species of bivalve mollusc in the Mediterranean, Pinna nobilis, Linnaeus 1758, while the aim of this work was to collect data on the biological diversity of bivalve molluscs on the collectors, including the determination of invasive and endemic species of marine organisms. During the analysis of the fouling community, a total of 19 species of bivalves from 9 families were determined from the collection of bivalve larvae. During the laboratory analysis, no invasive species of bivalves where determined, however, an invasive species of mollusk Syela plicata was determined
The importance of mathematics in marine ecosystems
No full textMatematika je neizostavan dio naših života, a matematičko je znanje nužno za sva područja znanosti. Kroz ovaj rad prikazat će se način na koji matematika i biologija funkcioniraju zajedno. Matematička biologija ima za cilj matematičke prezentacije i modeliranje bioloških procesa, koristeći tehnike i alate primijenjene matematike.
Proučavanje morskih ekosustava postaje sve važnije. Međutim, često se čini da su terenski pokusi vrlo skupi ili čak nemogući. To je jedan od razloga zašto matematičko modeliranje i računalne simulacije imaju vrlo važnu ulogu u ekologiji mora. U ovom radu razmatraju se različiti suvremeni pristupi modeliranju morskih ekosustava. Objašnjene su temeljne ideje i dano je nekoliko važnih primjera koji su korišteni u novim studijama.Mathematics is an indispensable part of our lives, and mathematical knowledge is necessary for all areas of science. Through this work, the way in which mathematics and biology work together will be shown. Mathematical biology aims at mathematical presentations and modeling of biological processes, using the techniques and tools of applied mathematics. The study of marine ecosystems is becoming increasingly important. However, it often seems that field trials are very expensive or even impossible. This is one of the reasons why mathematical modeling and computer simulations play very important role in marine ecology. This work discusses various modern approaches to modeling marine ecosystems. The basic ideas are explained and several important examples are given that have been used in new studies
Can the transition from standard to biodegradable material influence capture modes in gillnet fishery?
No full textU ovom diplomskom radu predstavljeni su rezultati testiranja jednostrukih mreža stajaćica izrađenih od standardnog najlonskog mrežnog materijala i jednostrukih mreža stajaćica izrađenih od biorazgradivog mrežnog materijala. Istraživanje je provedeno na sjeveroistočnom području Jadranskog mora. Provedena je kvalitativno-kvantitativna analiza sastava ulova različitih konfiguracija jednostrukih mreža stajaćica te je ustanovljeno da je najzastupljenija vrsta u ulovu ciljana vrsta Sparus aurata. Zabilježeni su svi načini ulova ciljane vrste ribolova u oka jednostrukih mreža stajaćica različitih konfiguracija. Ukupno je zabilježeno pet načina ulova, četiri zaglavljivanjem i jedan zaplitanjem: zaplitanjem mrežnog tega u i oko usta ribe, zaglavljivanjem za predio glave između usta i škržnog poklopca, zaglavljivanjem neposredno iza škržnog poklopca, zaglavljivanjem za početak dorzalne peraje i predjela od početka trbušne peraje do analnog otvora i zaplitanjem u mrežni teg. U prosjeku se u većini slučajeva ciljana vrsta lovila zaglavljivanjem za predio glave između usta i škržnog poklopca te zaglavljivanjem za početak dorzalne peraje i predjela od početka trbušne peraje do analnog otvora. Nije ustanovljena statistički značajna razlika vjerojatnosti zaglavljivanja i/ili zaplitanja ciljane vrste u oka mreža izrađenih od standardnog i biorazgradivog materijala.This thesis presents the results of testing gillnets made of conventional and biodegradable materials. The tests were carried out in the North-eastern Adriatic Sea. The qualitative and quantitative analysis of the fish caught with gillnets showed that the target species gilthead seabream Sparus aurata was the most abundant species in the catches. The different ways in which the target species are caught in the gillnets have been recorded. A total of five different capture modes were identified: catch with the teeth or mouth, catch with the head (between the mouth and operculum), catch behind the operculum, catch between the beginning of the dorsal fin and the area between the beginning of the pelvic fin and the anus, and by entanglement. On average, the target species was caught behind the operculum or between the beginning of the dorsal fin and the area between the beginning of the pelvic fin and the anus. No statistically significant difference in capture probability was found between the standard and the biodegradable gillnets
Strategic analysis of fishing cooperative Omega 3
No full textCilj rada bio je izraditi cjelokupnu stratešku analizu ribarske zadruge Omega 3 i utvrditi strateške čimbenike koji utječu ili mogu utjecati na razvoj zadruge te ocijeniti njen konkurentski položaj. U radu su korištene metode studije slučaja, strateške analize, analize financijskih izvještaja i SWOT analize. Rezultati skeniranja opće i poslovne okoline pokazuju da za analiziranu zadrugu prevladavaju prilike u odnosu na prijetnje iz opće i poslovne okoline. Analizom interne okoline utvrđeno je da u zadruzi prevladavaju pozitivni unutrašnji čimbenici. Strateška alternativa RZ Omega 3 u budućem srednjoročnom razdoblju je maksi-maksi strategija te bi trebalo maksimalno upotrebljavati snage da bi se potpuno iskoristilo prilike.The aim of the thesis was to prepare an overall strategic analysis of the Omega 3 fishing cooperative and to determine the strategic factors that influence or can influence the development of the cooperative, as well as to evaluate its competitive position. The methods of case study, strategic analysis, analysis of financial statements and SWOT analysis were used in the work. The results of the analyses of the general and business environment show that for there are more opportunities than threats from the general and business environment for the cooperative analysed. When analysing the internal environment, it was determined that positive internal factors predominate in the cooperative. The strategic alternative of RZ Omega 3 in the future medium-term period is a maxi-maxi strategy, and the strengths should be used to the maximum in order to fully exploit the external opportunities