Prvi nalaz iglice veličanstvene, Tylosurus acus imperialis (Rafinesque, 1810) (Osteichthyes: Belonidae) na području hrvatskog ribolovnog mora

Commercial purse seiner collected one specimen of the agujon needlefish, Tylosurus acus imperialis (Rafinesque, 1810), during its fishing activity on 17 July 2015 in the open sea area out off Mljet island (42º 41.9′ N; 17 º 18.1′ E, depth 120 m). Total length and weight of collected female specimen was 111.4 cm and 2048.11 g, respectively. Although this species was previously recorded exclusively entering the area of southern Adriatic Sea (Montenegro-Budva and Italy- Bari), this was its first appearance in the upper Adriatic and within Croatian fishing grounds.Dana 17. srpnja 2015. godine tijekom ribolovne aktivnosti na području otvorenog mora van otoka Mljeta (42º 41.9′ N; 17 º 18.1′E, na dubini od 120 m) plivarica za sitnu plavu ribu je zabilježila ulov iglice veličanstvene, Tylosurus acus imperialis (Rafinesque, 1810). Ukupna dužina tijela jedinke iznosila je 111,4 cm, dok je masa tijela iste iznosila 2048,11 g. Iako je pojava ove vrste bila zabilježena na području južnog dijela Jadranskog mora (Crna Gora-Budva, Italija-Bari), ovo je prvi nalaz iglice veličanstvene kako u hrvatskom tako i u sjevernom dijelu Jadrana općenito

SOME ANATOMIC AND MORPHOLOGIC CHARACTERISTICS OF CULTURED AND WILD TUNA

Cilj je ovog rada prikazati probavni sustav tuna, s posebnim osvrtom na jetra. Uzorci za istraživanje probavnih organa tuna uzeti su s uzgajališta tuna »Sardina« d.d. Postira. Obavljeno je istraživanje na 22 uzorka (razudba i fotografiranje organa, Canon digitalnim aparatom), 30 uzoraka jetara netovljenih tuna, 30 uzoraka jetara tovljenih tuna, te 20 histoloških uzoraka jetara prije i nakon tova. Kakvoća prehrane neposredno se odražava na razlikama dužinsko–masenih vrijednosti hepatosomatskog indeksa i same histologije jetara tovljene i netovljene ribe. Intenzivna prehrana bogata lipidima povećava količinu masti skladištene u jetrima i time uzrokuje veći hepatosomatski indeks tovljene tune. Histološka pretraga tovljene tune pokazuje početak masne degeneracije hepatocita s vakuolizacijom stanice i decentriranim jezgrama. Nedostatak eozinofilnih granula u citoplazmi hepatocita upućuje na nemogućnost obavljanja enzimatske aktivnosti stanice, odnosno njihovu disfunkciju.The main task of this paper is to describe digestive tract of bluefin tuna, with special focus on the liver. The samples for the research on tuna digestive tract where taken on the tuna farm »Sardina« d.d. Postira. The investigation were done on 22 samples (necropsy and photography of organs, Canon digital camera), 30 samples liver of unfatted tuna, 30 samples liver of fatted tuna and 20 histologic samples of liver before and after fattening. The quality of nutrition directly affects the differences of longitudinal and latitudinal values of the hepatosomatic index and the histology of liver of fatted and unfitted fish. Intensive, lipid–rich nutrition increases the quantity of the fat stored in liver therefore causing higher hepatosomatic index in fatted tuna. Histologic examination of fatted tuna indicates a beginning of hepatocytes degeneration with vacuolization of the cell and decentralized nuclei. Lack of eosinophilic granules in cytoplasm of hepatocytes indicates the cell’s inability of doing enzymatic activity, respectively its dysfunction

SOME ANATOMIC AND MORPHOLOGIC CHARACTERISTICS OF CULTURED AND WILD TUNA

Cilj je ovog rada prikazati probavni sustav tuna, s posebnim osvrtom na jetra. Uzorci za istraživanje probavnih organa tuna uzeti su s uzgajališta tuna »Sardina« d.d. Postira. Obavljeno je istraživanje na 22 uzorka (razudba i fotografiranje organa, Canon digitalnim aparatom), 30 uzoraka jetara netovljenih tuna, 30 uzoraka jetara tovljenih tuna, te 20 histoloških uzoraka jetara prije i nakon tova. Kakvoća prehrane neposredno se odražava na razlikama dužinsko–masenih vrijednosti hepatosomatskog indeksa i same histologije jetara tovljene i netovljene ribe. Intenzivna prehrana bogata lipidima povećava količinu masti skladištene u jetrima i time uzrokuje veći hepatosomatski indeks tovljene tune. Histološka pretraga tovljene tune pokazuje početak masne degeneracije hepatocita s vakuolizacijom stanice i decentriranim jezgrama. Nedostatak eozinofilnih granula u citoplazmi hepatocita upućuje na nemogućnost obavljanja enzimatske aktivnosti stanice, odnosno njihovu disfunkciju.The main task of this paper is to describe digestive tract of bluefin tuna, with special focus on the liver. The samples for the research on tuna digestive tract where taken on the tuna farm »Sardina« d.d. Postira. The investigation were done on 22 samples (necropsy and photography of organs, Canon digital camera), 30 samples liver of unfatted tuna, 30 samples liver of fatted tuna and 20 histologic samples of liver before and after fattening. The quality of nutrition directly affects the differences of longitudinal and latitudinal values of the hepatosomatic index and the histology of liver of fatted and unfitted fish. Intensive, lipid–rich nutrition increases the quantity of the fat stored in liver therefore causing higher hepatosomatic index in fatted tuna. Histologic examination of fatted tuna indicates a beginning of hepatocytes degeneration with vacuolization of the cell and decentralized nuclei. Lack of eosinophilic granules in cytoplasm of hepatocytes indicates the cell’s inability of doing enzymatic activity, respectively its dysfunction

Interakcija plivarice za ulov sitne plave ribe i njenih grabežljivaca – preliminarno istraživanje u istočnom Jadranu

Due to very good collaboration with one commercial purse seiner, using “Srdelara” and operating in fishing zone G, preliminary data concerning the interaction between small pelagic purse seine fishery and its predators were obtained. According to the notes taken by experience observer on-board in period from year 2013 to 2016, seems that tunas, dolphins and swordfish were the faithful companions of purse seiner fisherman with abundance of 68.6%, 22.0% and 9.4%, respectively. Although they were present all year round, their monthly pattern of appearance indicated that less tunas were recorded in May-June, more dolphins were noted from July to October while swordfish were mostly abundant in winter (January-March). Within the investigated period, slightly increasing trend of tuna and dolphins’ appearance was recorded, although statistically not significant. Analysing possible correlation between purse seine catches and predator’s abundances, revealed that appearance of tuna had negative impact on the catches (dispersion of schools), while realised catches in presence of dolphins were quite good so it seems that they tend to round up small pelagic fish schools.Zahvaljujući vrlo dobroj suradnji s ribarskim sektorom, točnije jednom komercijalnom plivaricom koja koristi plivaricu “Srdelaru” u ribolovnoj zoni G, su prikupljeni preliminarni podaci vezani uz interakciju ovog tipa ribolova i njegovih predatora. U razdoblju od 2013. do 2016. godine, prema podacima prikupljenim od strane iskusnog promatrača na palubi ove komercijalne plivarice, je utvrđeno da su tune, dupini i igluni najvjerniji pratioci ovog tipa ribolova te da je njihova abundancija redom bila 68,6%, 22,0% i 9,4%. Premda je uočeno da su navedeni grabežljivci prisutni tijekom cijele godine ipak je njihova pojavnost kolebala od mjeseca do mjeseca – najmanje tuna je zabilježeno u razdoblju od svibnja do lipnja, nešto više dupina je uočeno od srpnja do listopada, dok su igluni bili najbrojniji od siječnja do ožujka. Tijekom istraživanog razdoblja je utvrđeno blago povećanje broja tuna i dupina premda to povećanje nije bilo statistički značajno. Korelirajući ulove ostvarene istraživanom komercijalnom plivaricom i broja uočenih grabežljivaca, čini se da će u slučaju pojave tune ostvareni ulov biti manji s obzirom da ona rasprši ciljanu plovu sitne plave ribe, dok će relatvno dobar ulov ista plivarica ostvariti u prisutnosti dupina koji će uočenu plovu još više zbiti