Repository of the Department of Marine Studies at the University of Split
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Phenotip differences between wild and farmed sea bass and sea bream and their impact on consumption
No full textU ovom radu se analizira odnos potrošača prema konzumaciji komarče i lubina na području grada Splita. Posebno se analizira odnos potrošača prema komarči i lubinu podrijetlom iz uzgoja. Raspravlja se o utjecaju dobi, stupnju obrazovanja i socijalnom statusu potrošača na učestalost konzumacije ribe, a posebno na odnos prema ribi podrijetlom iz uzgoja. Također, u radu se interpretiraju najvažniji čimbenici (cijena, dostupnost, način ponude, kvaliteta i vrsta proizvoda) koji utječu na potrošnju ribe iz ulova i ribe iz uzgoja. Analiziraju se razlozi postojećih predrasuda potrošača prema ribi podrijetlom iz uzgoja. Posebna pažnja je posvećena mjerama koje je potrebno poduzeti u smislu edukacije potrošača i načina prezentacije i ponude ribe na tržištu u svrhu povećavanja potrošnje komarče i lubina podrijetlom iz uzgoja.This thesis analyzes relationship between consumers from city of Split towards sea bream and sea bass consumption. The consumer relationship with cultured sea bream and sea bass is particulary analyzed. The following items were discussed: the influence of age, degree of education and social status of consumers on fish consumption and in particular on the opinions toward the consumption of cultured fish. The most important factors (price, availability, supply, quality and type of product) affecting the consumption of both wild and cultured fish are interpreted. The reasons for the existing prejudice of consumers towards cultured fish are analyzed. Special attention is given to the measures that are needed, like consumer education as well as presentation and supply of the fish in the market, in order to increase consumption of cultured sea bream and sea bass
Rearing tehnology of common octopus Octopus vulgaris Cuvier, 1797
No full textU ovom radu predstavljena je važna jadranska vrsta, hobotnica Octopus vulgaris, Cuvier 1797,općenite značajke koje su karakteristične za ovu vrstu, njen rast i razvoj.Također, naveden je i gospodarski značaj kao i pokušaji uzgoja u kontroliranim uvjetima. Kao jedna od najvažnijih oktopodnih vrsta u Jadranu često je viđena namirnica u mnogim kućanstvima na obali RH, posebice u Dalmaciji.Obzirom na navedenu potražnjuhobotnica je uzeta kao idealni primjer za uzgoj u marikulturi. Rezultati dosadašnjih istraživanja pokazuju da hobotnica dobro podnosi uzgojne uvjete i u relativno kratkom vremenu postiže konzumnu veličinu.No, u uzgojnim uvjetima su primijećene pojave kanibalizma i sposobnost vrste da pobjegne iz uzgojnih jedinica, kao i potrebe za velikom količinom i raznovrsnom hranom, što dovodi do ekonomskih problema. Izuzev navedenog svi oktopodi pa tako i obična hobotnica služe kao izvor visokovrijednih bjelančevina u ljudskoj prehrani.Thepaperpresentsimportant octopod species in the Adriatic Sea known as common octopus (Octopus vulgaris Cuvier 1979)with its general characteristics, growth and development. Also, their commercial and economic importance as well as experimental attempts of cultivation. As one of the most important octopod species in the Adriatic, it is a commonly used as food in many households on the Croatian coast, especially in Dalmatia.Consequently, octopus has been taken as an ideal example for cultivation in mariculture. According tothe results of conducted experimental research, octopus has shown good adaptations to captive conditions and short growing time to consumption size. However, cannibalism and the ability of the species to escape from cageunits has been observed, as well as the need for large amounts and different types of food, leading to economic problems. In addition, all octopods, including the common octopus, serve as a source of high-quality protein in human consumption
Use of selective grids in trawl fishery in north Atlantic area
No full textPovećanjem veličine oka, ili promjenom geometrije oka, često nije moguće značajno unaprijediti selektivnost pridnene povlačne mreže koće. Iz tog razloga često se uz vreću koriste različite selektivne rešetke kako bi se unaprijedile selekcijske osobine povlačnih alata. U ovom radu ukratko je opisan razvoj selektivnih rešetki u pridnenom koćarenju na području sjevernog Atlantika. U suštini, rešetke se mogu podijeliti na one koje se koriste pri lovu kozica i one koje se koriste prilikom lova riba. Nordmöre rešetka je najpoznatija rešetka koja se koristi u pridnenom koćarenju kod ciljanog izlova kozice. Unatoč tome što se upotrebom ove rešetke dobije gotovo čist ulov kozice, znanstvenici još uvijek intenzivno rade na smanjenju ulova nedoraslih primjeraka ne-ciljanih ribljih vrsta prilikom upotrebe ove rešetke. Rešetke koje se koriste prilikom izlova ribe služe kako bi se iz ulova izdvojio što veći broj nedoraslih riba, zadržavajući po mogućnosti što veći broj jedinki iznad minimalne lovne duljine. Trenutno se na području sjevernog Atlantika koristi nekoliko različitih metalnih rešetki, iako se u posljednje vrijeme sve više koriste rešetke izrađene od različitih mekših materijala.Simple increase in codend mesh size, or change in codend mesh geometry, is often not sufficient to improve species and size selection in bottom trawl fishery. To supplement the codend size selection, selective grids of different sizes are often used. This paper gives a brief description of the grids used in the north Atlantic bottom trawl fishery. In general, grids can be classified in two different categories, grids used in the shrimp trawls and grids used in the fish trawls. The most popular grid used in the shrimp trawls is called Nordmöre grid. The purpose of the Nordmöre grid is to retain shrimp and exclude all unwanted fish species. The grid proved to be very efficient, except in excluding undersized individuals of bycatch fish species. The functioning of the grids used in the fish trawls is different compared to Nordmöre grid, because their purpose is to reduce the catch of small fish when targeting cod. Currently in the north Atlantic several different metal grids are used in fish trawls, although recently grids made of the softer materials are becoming increasingly popular
Karakteristike nekih deformacija kostura mlađih lubina Dicentrachus labrax (Linnaeus, 1785) u uzgoju
No full textMalformacije se javljaju kod uzgojnih populacija mlaĎi lubina, a utječu na zdravlje ribe i njezinu ekonomsku vrijednost na trţištu. Posebna paţnja u radu usmjerena je na metodologiju i proces izdvajanja deformirane mlaĎi lubina u uzgoju. U svrhu pravilnog načina vredovanja deformiteta napravljenje su rendgenske slike cjelokupnog kostura izdvojenih jedinki. Zbog pojavnosti deformacija na kraljeţnici (>3%) u drugoj mrijesnoj seriji je obavljeno izdvajanje deformiranih jedinki od zdravih. U ukupnom uzorku bile su 103 jedinke. Najveći broj jedinki je imao skoliozu (83%), dvije jedinke su imale lordozu (1,9%), dok je pet jedinki imalo kifozu (4,8%). Normalnu kraljeţnicu je imalo 13 jedinki, ali su iste imale oštećen operkulum (12,6%). U uzgojnoj sredini, uz dane starosti jedinki pratile su se vrijednosti abiotičkih faktora: kisik, temperatura, ugljični dioksid i amonijak.Malformations that occur in breeding populations are the causative agent which affects the health of the fish and its economic value. Particular attention in this thesis is focused on metodology and the process of selection of sea bass juveniles with deformities. In order to obtain a better insight into the type of deformities, X-ray images of the entire skeleton were taken. Because of the manifestation with deformities (>3%) in the second hatchery series, a selection has been made in the pools, and within this gruop healthy and deformed individuals were divided. There were 103 individuals in the sample. The largest number of fishes had a scoliosis (83.0%). There were two individuals with lordosis (1.9%), five with kifosis (4.8%), and thirteen with normal spine, but with damaged operculum (12.6%). In the breeding environment, besides the age of individuals, other values were observed such as: oxygen, temperature, carbon dioxide and ammonia
Impacts of postmorten handling on sensory characteristics of prawns
No full textMelanoza je enzimatska reakcija bezopasna za potrošače i nije izravno povezana s kvarenjem rakova, ali utječe na senzorska svojstva umanjujući rok trajanja i kvalitetu proizvoda. U ovom radu istraživan je utjecaj primjene kalijevog metabisulfita, 4-heksorecinola i ekstrakta zelenog čaja, samostalno ili u obliku komercijalno dostupnog preparata (Neocel, Crustaxyl) na senzorske promjene i razvoj melanoze u kozici, Parapenaeus longirostris (Lucas, 1846). Dodatno, tretmani su uspoređeni tijekom 19 dana pohrane u ledu i mokrom ledu. Senzorska svojstva kozica mijenjala su se zavisno od primijenjenog tretmana. Rezultati ukazuju na to da se melanoza kao prirodni proces ne može zaustaviti nego samo spriječiti na određeno vrijeme. Najučinkovitiji se pokazao tretman Neocel u koncentraciji od 1,5% primijenjen na kozicama skladištenim u mokrom ledu koji je odgodio tamnjenje tijela punih 19 dana pohrane. Dobre rezultate postigao je 3% Neocel u kozicama skladištenima u mokrom ledu koji je spriječio razvoj melanoze do 17 dana. Najlošijima su se pokazali tretmani 5% kalijevog metabisuflita skladištenog u ledu i mokrom ledu, koji su 13. dan pohrane postigli maksimalnu ocjenu za tamnjenje tijela. Svi tretmani pokazali su bolju učinkovitost na kozicama tijekom pohrane u mokrom ledu. Osim tretmana, u očuvanju kvalitete sirovine od velikog značaja bili su pravilno hlađenje i postupci rukovanja te higijena postupaka.Melanosis is an enzymatic reaction harmless to consumers and not directly associated with spoilage of crabs, however it affects sensory properties thus reducing the shelf life and quality of the product. In this thesis, the effect of potassium metabisulfite, 4-hexylresorcinol and green tea extract, alone or in the form of a commercially available product (Neocel, Crustaxyl) on the sensory changes and development of melanosis in deep-water rose shrimp Parapenaeus longirostris (Lucas, 1846) was investigated. Additionally, treatments were compared over a period of 19 days in ice and slurry ice. Sensory properties of shrimps changed depending on the treatment applied. The results suggest that melanosis as a natural process cannot stop and can only be prevented for a particular time. The most effective treatment was Neocel in concentration of 1.5% used on shrimps stored in slurry ice. This treatment postponed melanosis during 19 days of storage. Good results were achieved by 3% Neocel stored in slurry ice which prevented the development of melanosis over 17 days. On day 13 of storage, shrimps treated with potassium metabisulfite (5%) achieved maximum quality index grades for colour in shrimps stored in both ice and slurry ice. All treatments showed better efficacy on shrimps stored in slurry ice. Beside treatment, the quality of the raw material was greatly depended on chilling and handling procedures as well as hygiene procedures
Hystology of the European sea bass Dicentrarchus labrax (Linnaeus 1758) organ systems
No full textU ovom radu opisana je histologija glavnih organa zdravog lubina u svrhu produbljenja znanja o normalnoj strukturi tkiva, što je bitno kako bi se na mikroskopskoj razini mogle uočiti promjene tkiva u bolesnih organizama. Također, u radu je dan pregled zabilježenih bolesti uzgojnog lubina. Lubin Dicentrarchus labrax (Linnaeus, 1758) jedna je od najzastupljenijih vrsta u kaveznom uzgoju na području Sredozemlja, a posljednjih nekoliko desetaka godina prepoznat je kao koristan model organizam u imunologiji, ekotoksikologiji, genomici te studijama ponašanja. Povelik je broj bolesti koje uzrokuju patogeni virusi, bakterije i paraziti, a zahvaćaju sve životne stadije lubina, što naposljetku dovodi do značajnih gubitaka u uzgoju, ali i narušene dobrobiti u laboratorijskim uvjetima. Većina bolesti rezultat je interakcije ekoloških čimbenika i genetske predispozicije, a sama procjena neke bolesti često zahtijeva korištenje različitih dijagnostičkih alata, kao što je histopatologija.This thesis describes the histology of healthy sea bass main organs in order to further the knowledge about the normal tissue structure, which is essential for detecting tissue changes in diseased organisms at the microscopic level. Also, a review of reported diseases of the cultured sea bass is given. Sea bass Dicentrarchus labrax (Linnaeus, 1758) is one of the most prominent species in Mediterranean aquaculture, and in recent decades has been recognized as a useful model organism in immunology, ecotoxicology, genomics and behavioral studies. Numerous diseases, caused by pathogenic viruses, bacteria and parasites, affect all life stages of sea bass, ultimately leading to significant losses in aquaculture, but also impaired welfare in laboratory conditions. Most illnesses result from the interaction of ecological factors and genetic predisposition, and the assessment often requires the use of various diagnostic tools, such as histopathology
Biological and ecological characteristics of stargazer Uranoscopus scaber Linnaeus, 1758 in southern Adriatic Sea
Get PDFTijekom ovog istraživanja na području južnog Jadrana prikupljeno je ukupno 1279 jedinki bežmeka Uranoscopus scaber Linnaeus, 1758. Raspon ukupnih duljina tijela jedinki bio je od 8,45 do 36,0 cm (18,12 ± 3,54 cm), a mase od 11,52 do 618,7 g (102,25 ± 59,27 g). Omjer ženki i mužjaka u uzorku iznosio je 1:0,82. Statistički značajne razlike zabilježene su u srednjim vrijednostima jedanaest mofometrijskih odnosa između ženki i mužjaka. Duljinsko-maseni rast bežmeka je izometrijski (b = 3,016), a srednja vrijednost indeksa kondicije iznosila je 1,541. Intenzitet hranjenja najveći je u proljeće, a ribe su neophodna i glavna hrana tijekom godine. Starost bežmeka je određena očitavanjem otolita. Najstarija ženka imala je 8 godina, a najstariji mužjak 6 godina. Rast bežmeka je opisan von Bertalanffyjevim modelom rasta L∞ = 48,93 cm, K = 0,12, t0 = -1,6, R2 = 0,94. Mužjaci bežmeka postaju spolno zreli (Lt = 12,19 cm) pri manjim ukupnim duljinama tijela nego ženke (Lt = 14,12 cm). Fekunditet je bio relativno nizak, a sezona mriještenja bežmeka u južnom Jadranu je od ožujka do listopada. Najveće srednje vrijednosti gonadosomatskog indeksa zabilježene su u svibnju za ženke i u lipnju za mužjake. Vrijednosti ribolovne smrtnosti (F = 0,411) su bile veće od vrijednosti prirodne smrtnosti (M = 0,128).In the present study, a total of 1279 specimens of the stargazer Uranoscopus scaber Linnaeus, 1758. were collected. Total lenght of stargazer ranged from 8.45 to 36.0 cm (18.12 ± 3.54 cm), while total weight ranged from 11.52 to 618.7 g (102.25 ± 59.27 g). Female to male ratio was 1:0.82. The differences between the eleven mean values of the measured morphometric characteristics in females and males were statistically significant. The length-weight relationship showed isometric growth (b = 3.016) and estimated condition factor was 1.541. The highest feeding intensity of the stargazer was recorded during spring and the dominat food component was fish. Age of the stargazer was determined by otolith reading. Maksimum ages for females and males were 8 and 6. The growth of fish was described using the von Bertalanffy growth model: L∞ = 48.93 cm, K = 0.12, t0 = -1.6, R2 = 0.94. Males of the stargazer reached maturity (TL = 12.19 cm) at smaller lengths than females (TL = 14.12 cm). The fecundity of females was relatively low, while spawning of the stargazer in southern Adriatic Sea takes place between March and October. The highest mean values of gonadosomatic index were recorded in May for females and in June for males. Fishing mortality values of the stargazer (F = 0.411) were higer than values of natural mortality (M = 0.128)
Antimicrobial activity of drugs
No full textKada normalna obrana tijela ne može spriječiti ili nadvladati bakterijske infekcije, često se koriste antimikrobni lijekovi. Oni djeluju na način da ubijaju mikroorganizme ili ometaju njihov rast, a pritom moraju djelovati bez štetnog učinka na domaćina. Antibiotici su jedno od najvažnijih otkrića suvremene medicine. Uvođenje penicilina te drugih antimikrobnih lijekova, rezultiralo je liječenjem do tada neizlječivih bolesti. U radu je ukratko obrađen način djelovanja pojedinih skupina antibiotika na bakterijske stanice. Današnjem napretku kojeg su omogućili antimikrobni lijekovi, prijeti razvoj rezistencije bakterija na određene antibiotike upravo kao posljedica prekomjernog i nepravilnog korištenja antibiotika. U radu su također navedeni i opisani mehanizmi koje su bakterije razvile kako bi stekle otpornost na antibiotike.When normal body defence cannot prevent or overcome bacterial infections, antimicrobial drugs are often used. They act to kill or prevent the growth of microorganisms, without negative impact on the host. Antibiotics are one of the most important discoveries of modern medicine. The introduction of penicillin and other antimicrobial drugs resulted in treating incurable diseases. This paper briefly explains ways of action in which certain groups of antibiotics affect bacteria. Today's progress made possible by antimicrobial drugs is threatened by the development of bacterial resistance to certain antibiotics, precisely as a result of excessive and inappropriate use of antibiotics. This paper also outlines and describes the mechanisms developed by the bacteria to gain antibiotic resistance
Biomimetics: Robotic fish
No full textU ovom radu opisana su dva istraživanja u kojima su se koristile biomimetičke robotske ribe. Biomimetika je analitički i sintetski proces u kojem biolozi i inženjeri dupliciraju biološke strukture i/ili funkcije te ih primjenjuju u mehaničkim strojevima, robotima itd. Biomimetičke robotske ribe izgrađuju se iz tri razloga: za testiranje bioloških hipoteza, za izradu novog dizajna za podvodna vozila te za zabavu ili edukaciju. Biolozi i inženjeri prvo izaberu ciljnu funkciju ili ponašanje robota, zatim odrede procese kojima će stvoriti tu funkciju ili ponašanje te na kraju rade planove dizajna. Robotske ribe se izrađuju za modeliranje pojedinih struktura, pojedinih vrsta ili cijele populacije riba. One mogu ili ne moraju biti samo-pogonske, autonomne, pogonjene ugrađenim baterijama ili kontrolirane računalima. Mnogi projekti robotskih riba proučavaju propulziju (pogon), s tijelima i perajama napravljenima tako da proizvode biorealističnu pokretljivost.In this paper, two case studies in which biomimetic robotic fish have been used, are described. Biomimetics is an analytical and synthetic process by which biologist and engineers duplicate biological structures, function, or both, and apply them in mechanical machines, robots etc. Biomimetic robotic fish are built for three reasons: to test biological hypotheses, to engineer novel designs for underwater vehicles, and for entertainment or education. First, biologists and engineers formulate the intended function or behavior of the robot, the processes that will create the function or behavior, and at the end they make design plans. Robotic fish are built to model individual structures, particular species, or whole populations of fish. Robotic fish may or may not be self-propelled, behave autonomously, be powered by on-board batteries, or be controlled by computers. Many robotic fish projects study propulsion, with body and fins built to produce biorealistic locomotion
Modelling the dynamics of early fish stages
No full textRad daje pregled različitih modela kojima se znanstvena zajednica služi za modeliranje dinamike ranih stadija ribe. Opisana je primjena modela na jajašca i larve gospodarski i ekološki važnih vrsta inćuna (Engraulis encrasicolus) i srdele (Sardina pilchardus) u Jadranskom moru i Humboldtovoj struji i hujice (Ammodytes marinus) u Sjevernom moru. Diskutirane su primjene dviju vrsta modela: hidrodinamičkog i individualno temeljenog modela (engl. individual based model, IBM). U prezentiranim znanstvenim člancima istraživao se utjecaj fizikalnih i bioloških parametara na mrijest i novačenje larvi. U području zapadne Humboldtove struje rezultati su pokazali maksimalno zadržavanje zimi a minimalno ljeti. Fitoplanktonski maksimumi su se pokazali iznimno važnim (kao dostupnost hrane), ali se vremenski ne poklapaju s maksimumom populacije larvi. Čestice veće plovnosti su pokazale kraće zadržavanje. Dubina piknokline i gustoća morske vode su značajni parametri za određivanje vremena i postotka zadržavanja kao i dubina ispuštanja jajašaca te vertikalne migracije larvi. Prilikom simulacija unazad u vremenu disperzija se pokazala iznimno važnom za mrijest, preživljavanje i razvoj ribljeg jata. U Jadranskom moru je najveća koncentracija larvi (> 25%) uz talijansku obalu i to ispred regija Abruzzo i Molise. Gotovo u nijednom području uz zapadnu obalu osim uz deltu rijeke Po nije došlo do zadržavanja larvi dok je na istočnoj obali zadržavanje puno veće Visoka produktivnost morske vode se pokazala kao glavni faktor koncentracije juvenila, a tome osim riječnih dotoka pridonose i fizikalni faktori kao što su fronte i izranjanje (upwelling).This paper reviews numerical models that are used for modelling early fish stages. Model application on fish eggs and larvae is shown in the example of economically and ecologicaly important species such as European pilchard (Sardina pilchardus) and European anchovy (Engraulis encrasicolus) in the Adriatic and Humboldt's current and Raittꞌs sand eel (Ammodytes marinus) in the North Sea. Two types of models are discussed: hydrodynamic and IBM (individual based model). The influence of physical and biological factors on spawning and recruitment are described in the presented scientific articles. Results showed that in the northern Humboldt current the maximum retention appears during winter and mi-nimum during summer. Although the phytoplanktonic maxima are important as a source of nutrition they do not coincide with the maximum population of larvas. Particles of greater buoyancy have shown shorter retention. The pycnocline depth, sea water density, depth of the egg release and the vertical migrations have shown to be of great importance for retention. During backtracking, dispersion is a very important factor for spawning, larval survival and for the formation of fish flock. The majority of larval concentration in the Adriatic was along the west coast (>25%) in front of Abruzzo and Molise regions. Along the east coast and in front Po river delta retention was noticeable which was not the case along the Italian coast. The main factor for juvenile concentration seems to be high productivity with river inflows and physical factors like water fronts and upwelling contributing to it