MARIKULTURA NA HRVATSKIM OTOCIMA

The first attempts of intensive mariculture in Croatia commenced at the very beginning of 1980’s. The mid-eighties brought an expansion of mariculture production, which has been continuously increasing. A few different marine organisms are intensively cultured - both fish and shellfish. Among them commercially most important and highly valued species are sea bass Dicentrarchus labrax and sea bream Sparus aurata. Mussel Mytilus galloprovincialis and oyster Ostrea edulis are the most important shellfish. Fish species such as dentex Dentex dentex, red sea bream Pagrus major and sheepshead bream Puntazzo puntazzo are reared too, but in a rather small quantities. Only recently the rearing, on-growing- of bluefin tuna Thunnus thynnus started in Croatia. The juveniles (70%) are reared in a Croatian hatcheries, and 30% has to be imported mainly from Italy and France, due to a higher demand for this kind of culture among the small growers. Croatian part of Adriatic sea possesses a number of geomorfologicaly suitable sites and meteorological conditions which determined the choice - type - of intensive culture. All fish species are reared in a floating cages. The choice of cages i. e. semi off-shore or floating frames, size, rearing volume and design depend on the investors personal preference. The annual turnouf of a market size bass was about 600t and 300t bream in 1996., by 10 island farms which is 70% of total production in Croatia. Including other cultured fish species last year production was up to 1000t, and it™s being estimated to be about 1300t in the following year. The shellfish production on the islands is usually individual attempt of farmers, producing minor quantities mostly in polyculture. This production has bigger potential but it’s limited owing to the EU quality control regulations which do not allow the export, and by domestic market which has drastically decreased due to the collapse of tourism during the recent war. Almost 80% of consumption fish is exported to Italy and bluefin tuna to Japan exclusively. It’s expected that demand for mariculture products, fish and shellfish, will increase on domestic market. These expectations are based on a possibility of new local investments and a market perspectives on account of tourism revival which seems to be the most important for the small island producers. The reasons for having implemented farms on islands are unexploited good environmental conditions, less risk from the coastal and industrial pollution, less users conflicts and less comptetition for locations and concessions. Island mariculture is a part of political or socio-demografic orientation of the government, but regarding producers this option is voluntary.Prvi intenzivniji pokušaji proizvodnje marikulture u Hrvatskoj počeli su početkom 1980-ih godina. Sredinom osamdesetih dolazi do širenja i razvijanja marikulture, sa stalnom tendencijom rasta. Intezivno se uzgaja nekoliko vrsta riba i školjaka. Od riba komercijalno su najvažnije i vrlo cijenjene lubin Dicentrarchus labrax i orada (podlanica) Sparus aurata, a od školjaka su najvažnije dagnja Mytilus galloprovincialis i kamenica Ostrea edulis. Također se, iako u malim količinama, uzgajaju zubatac Dentex dentex, japanski pagar Pagrus major i pic Puntazzo puntazzo. Nedavno se započelo s uzgojem tune Thunnus thynnus. Riblji mlađ uzgojen u hrvatskim mrjestilištima pokriva 70% domaćih potreba, dok se zbog veće potražnje mlađa poglavito malih uzgajivača, 30% uvozi uglavnom iz Italije i Francuske. Na hrvatskoj strani Jadranskog mora postoje brojni predjeli čije su geomorfološke i meteorološke značajke odredile način ove vrste intenzivnog uzgoja. Sve se riblje vrste uzgajaju u plutajućim kavezima. Izbor kaveza, odnosno tzv. polupučinski kavezi ili kavezi pogodniji za zaštićenije uvale, veličina, uzgojni volumen i konstrukcija ovise o ulagačevu osobnom izboru. Godišnja proizvodnja 1996. ostvarena u 10 uzgajališta smještenih na otocima iznosila je oko 600 t konzumnog lubina i 300 t podlanice, što čini 70% ukupne proizvodnje u Hrvatskoj. Uključujući i druge uzgojne vrste, prošlogodinja je proizvodnja iznosila do 1 000 t, a predviđa se da bi mogla iznositi oko 1 300 t u sljedećoj godini. Proizvodnja školjaka na otocima obično je osobni pokušaj uzgajivača, koji proizvode manje količine, i to uglavnom u polikulturi. Ovakva proizvodnja ima veće mogućnosti, ali je dijelom ograničena zakonima o kvaliteti kontrole EZ-a, po kojima izvoz školjaka nije dopušten, a dijelom i situacijom na domaćem tržištu koje je znatno smanjeno zbog kolapsa turizma u vrijeme nedavnog rata. Gotovo 80% konzumne ribe izvozi se u Italiju, a tuna se isključivo izvozi u Japan. Očekuje se da će zahtjevi za morskim proizvodima, ribama i školjkama, porasti na domaćem tržištu. Ova se očekivanja temelje na mogućnostima novih ulaganja, kao i na tržišnim perspektivama ponovno oživjelog turizma koji je, čini se, od osobite važnosti upravo za male otočne uzgajivače. Neiskorišteni dobri uzgojni uvjeti, mali rizik od obalnih i industrijskih onečišćivača, manje vlasničkih nesporazuma, manja konkurencija za lokacije i koncesije razlozi su otvaranja farmi na otocima. Razvoj marikulture na otocima dio je i političke ili socio-demografske orijentacije vlade, ali iskorištavanja ovih mogućnosti ovise o odabiru proizvođača

HRANIDBA KAO MOGUĆI ETIOLOŠKI UZROČNIK SINDROMA ZIMSKE BOLESTI U PODLANICE (Sparus aurata L.)

The circumstance of winter disease phenomenon in intensively reared sea bream (Sparus aurata L.) has been described. It’s occurence in Mediterranean has been registered and reported by several authors. The aim of this paper is to contribute to the comprehension on the aethiology of this syndrome which is causing significant losses in one year old cultured fish. Different types of commercial diets were introduced during 1994/95 rearing season to the sea bream reared in floating cages. The feeds were displaying differences in energetic compound level and vitamin A, D3 and E content. Health difficulties and mortality in the observed fish groups at the beginning of the problem, did not indicate any biotic agent as being responsible for such condition. Clinical features and mortality in the groups affected by winter disease syndrome were increasing by low sea temperature and correlating with feeding period by food containing low levels of protein, lipids and vitamins. Pathological findings were in particularly related to the organs involved in digestion. Growth rate was characteristic for the group that were suffering winter disease, where increasing in length was not followed by body weight. Clinical signs, simptomathology related to the organs involved in digestion, liver histology analyses, weight losses and pattern of weight and length relation, correlation between used feeds and occurrence of winter disease, implicated nutrition as one of most possible ethiological agent of this condition. Nutritional interventions applied contributed in comprehension of the winter disease syndrome. The relationship between nutritional requirements, particularly regerding autumn-winter period, has been researched and analyzed. The results approved our basic hypothesis.Opisane su okolnosti u kojima se pojavila zimska bolest u intenzivno uzgajane podlanice (Sparus aurata L). Nekoliko je autora ustanovilo i izvijestilo o njezinoj pojavi u zemljama Sredozemlja. Svrha je ovoga rada da pridonese razumijevanju etiologije ovoga sindroma koji uzrokuje značajne gubitke jednogodišnje ribe. Različite vrste komercijalnih hrana uvedene su u hranidbu intenzivno uzgajane podlanice u sezoni 1994/95. Hrane su se razlikovale uenergijskoj jačini i količini vitamina A, D3 i. Početkom zdravstvenih poteškoća i uginuća promatranih grupa riba ništa nije upućivalo na uzročnika biotske etiologije. Klinički znakovi i uginuća u grupama riba na koje je djelovala zimska bolest povećavali su se padom temperature mora i bili su u vezi s razdobljem u kojem je hrana sadržavala malu količinu bjelančevina, masti i vitamina. Patološki su se nalazi poglavito odnosili na organe koji sudjeluju u probavi. Prirast je bio karakterističan za grupu koja je oboljela od zimske bolesti, pri čemu povećanje u dužinu nije pratio i porast tjelesne težine. Klinički znakovi, simptomatologija probavnih organa, histološki nalazi jetre, gubitak biomase, obrazac odnosa težine i dužine, povezanost upotrijebljenih hrana i pojave zimske bolesti, upozoravaju na hranidbu kao najvjerojatniji etiološki uzročnik opisane pojave. Intervencije u hranidbi koje smo upotrijebili pomogle su u razumijevanju pojave sindroma zimske bolesti. Odnos između hranidbenih potreba, osobito u jesensko-zimskom razdoblju, proučavan je i analiziran. Rezultati su potvrdili našu osnovnu pretpostavku

Fish Farms at Sea: The Ground Truth from Google Earth

In the face of global overfishing of wild-caught seafood, ocean fish farming has augmented the supply of fresh fish to western markets and become one of the fastest growing global industries. Accurate reporting of quantities of wild-caught fish has been problematic and we questioned whether similar discrepancies in data exist in statistics for farmed fish production. In the Mediterranean Sea, ocean fish farming is prevalent and stationary cages can be seen off the coasts of 16 countries using satellite imagery available through Google Earth. Using this tool, we demonstrate here that a few trained scientists now have the capacity to ground truth farmed fish production data reported by the Mediterranean countries. With Google Earth, we could examine 91% of the Mediterranean coast and count 248 tuna cages (circular cages >40 m diameter) and 20,976 other fish cages within 10 km offshore, the majority of which were off Greece (49%) and Turkey (31%). Combining satellite imagery with assumptions about cage volume, fish density, harvest rates, and seasonal capacity, we make a conservative approximation of ocean-farmed finfish production for 16 Mediterranean countries. Our overall estimate of 225,736 t of farmed finfish (not including tuna) in the Mediterranean Sea in 2006 is only slightly more than the United Nations Food and Agriculture Organization reports. The results demonstrate the reliability of recent FAO farmed fish production statistics for the Mediterranean as well as the promise of Google Earth to collect and ground truth data