The composition of demersal communities of deep Adriatic and the population structure of the commercially most important species

Ovaj rad je napravljen na osnovu podataka prikupljenih tijekom istraživanja pridnenih zajednica u okviru međunarodnih projekata EU MEDITS i FAO AdriaMed Deep Sea Survey. Cilj ove disertacije je opisivanje sastava pridnenih zajednica i demografske strukture populacija gospodarski najvažnijih vrsta dubokog Jadrana, usporedba sastava pridnenih zajednica obzirom na dubinu mora, proučavanje promjena u razdoblju od 1994. do 2008. godine, te davanje preporuka za održivo gospodarenje i zaštitu. Tijekom istraživanja ukupno je zabilježeno 339 vrsta riba, rakova i glavonožaca na cjelokupnom području. U najdubljem dijelu zabilježene su i tri nove vrste za Jadran. Najzastupljenije vrste na području kontinentskog slaza od 200 do 800 m prema masi bile su Lepidopus caudatus, Merluccius merluccius te Micromesistius poutassou, a u najdubljim dijelovima Jadrana Galeus melastomus te Trachyrhynchus trachyrhynchus. U razdoblju od 1994. do 2008. godine zabilježen je pad gustoće populacija u svim dubinskim područjima, osobito u plićem dijelu Jadrana. Multivarijatna analiza sastava pridnenih zajednica pokazala je postojanje značajne razlike između različitih područja dubokog dijela Jadrana. Uočena je stratifikacija demografske strukture populacija najvažnijih vrsta obzirom na dubinu. Trenutno stanje pridnenih zajednica dubokog dijela Jadrana upućuju na potrebu uvođenja preventivnih mjera zaštite tog područja.This thesis is based on samples and data collected during investigation of demersal communities conducted in a framework of international projects EU MEDITS from 1994 to 2008 and FAO AdriaMed from 2008 to 2010. Objectives of this thesis were description of composition of demersal communities and demographic structure of populations of most important species living in the deep Adriatic, comparative analysis of composition of demersal communities with respect to depth, analysis of changes that occurred in a period from 1994 to 2008, and creation of recommendations for the protection of the investigated area. During this study total of 339 species of fish, crustaceans and cephalopods were recorded in the entire study area. Three species new for the Adriatic were recorded in the deepest part. On the continental slope, most common species by biomass were Lepidopus caudatus, Merluccius merluccius and Micromesistius poutassou, while in the deepest part of the Adriatic most common species were Galeus melastomus and Trachyrhynchus trachyrhynchus. In a period from 1994 to 2008 a decrease in population densities were noted in all depth strata and it was especially evident in shallow areas. Multivariate analysis of composition of demersal communities showed statistically significant differences between areas in the deep Adriatic. Further more, demographic stratification of population structures of the most important species was noted with respect to depth. The recent state of demersal communities in the deep part of Adriatic indicates a need for introduction of preventive protection measures for this area

Nalaz vrste Neorossia caroli (Jouben, 1902) u srednjem Jadranu (hrvatske vode)

Two specimens of Neorossia caroli have been recorded for the first time in the central Adriatic Sea. They were caught in summer 2004 with a bottom-trawl net during a single tow at depths between 449 and 594 m in Croatian waters. Up to now N. caroli has never been found in the central Adriatic area. This finding represents a northernmost extension in the known range of the species N. caroli in the Adriatic Sea. Recorded specimens were both adult and mature males with mantle lengths of 42 and 37 mm. They counted 21 and 16 spermatophores, respectively. The measurements from both individuals are reported, including beak standard dimensions.Dva primjerka vrste Neorossia caroli po prvi put su nađena u hrvatskim vodama. Ulovljeni su u ljeto 2004. godine dubinskom povlačnom mrežom – koćom, tijekom jednog potega, na dubini između 449 i 594 m. Vrsta do sada nije zabilježena na području srednjeg Jadrana, te ulovljeni primjerci ujedno predstavljaju najsjeverniji nalaz ove vrste u Jadranskom moru. Nađene jedinke bile su spolno zreli mužjaci, dužine plašta 42 i 37 mm, u kojima je nađeno 21 odnosno 16 spermatofora. U radu se iznose osnovni morfomertijski podaci ulovljenih primjeraka, uključujući dimenzije kljuna

Širenje invazivnih školjkaša Anadara kagoshimensis i Anadara transversa u sjevernom i srednjem Jadranu

Two non-indigenous invasive bivalve species, Anadara kagoshimensis (Tokunaga, 1906) and Anadara transversa (Say, 1822), were recorded for the first time in the open waters of the eastern Adriatic Sea trawling grounds. Samples of these species were collected in 2008–2011 with modified beam trawl (rapido) during the SoleMon project, a project aimed at investigating the northern and central Adriatic Sea. In the years following its first record in 2008, the abundance of A. kagoshimensis increased in the area of investigation off the Istrian coast. The highest recorded abundance index per station was 1089 N km-2 in 2011. Species was present at depths from 31 to 41.5 m. Presence of Anadara transversa was recorded only at one station in 2011, in the middle of the open Adriatic between 70 and 72.5 m depth. The possible vectors of invasion of these species, from the western Adriatic coast to the eastern, are discussed.Dvije strane invazivne vrste školjkaša, Anadara kagoshimensis (Tokunaga, 1906) i Anadara transversa (Say, 1822), su po prvi put zabilježene u otvorenim vodama na koćarskim dnima u istočnom dijelu Jadranskoga mora. Uzorci ovih vrsta su sakupljeni za vrijeme SoleMon porojekta kojim je istraživano područje sjevernog i srednjeg Jadrana, u razdoblju od 2008. do 2011., a korišten je modificirani rampon (rapido). U godinama koje su slijedile nakon prve zabilješke 2008., abundancija vrste A. kagoshimensis se povećala na području istraživanja otvorenih voda uz obalu Istre. Najveća zabilježena vrijednost indeksa abundancije po postaji je bila 1089 N km-2, a zabilježena je 2011. godine. Vrsta je bila prisutna na dubinama od 31 do 41,5 m. Prisutnost vrste Anadara transversa je zabilježena samo na jednoj postaji 2011., u otvorenom Jadranu, na dubinama od 70 do 72,5 m. Analizirani su mogući vektori širenja ovih invazivnih vrsta sa zapadne obale Jadrana na istočnu

Opis strukture zajednica školjkaša u hrvatskom dijelu Jadranskog mora - istraživanje hidrauličnom dredžom

Hydraulic dredge surveys of bivalve communities in the Croatian part of the Adriatic Sea were conducted from the Island of Rab in the north to the river Neretva estuary in the south during 2007 and 2008. The main objective of the study was to describe distribution and community structure of bivalves on soft sediments along the eastern Adriatic, primarily focusing on commercially important species in five main bivalve harvesting areas. A total of 105 hydraulic dredge samples were collected at depths ranging from 1 to 11 m. Sampled bivalves were separated in the field and frozen for later laboratory analysis that included species identification, abundance and biomass determination. Live specimens of 54 bivalve taxa were collected during this study, while 87 taxa were represented by empty shells. Shells of the non-indigenous bivalve Anadara demiri were recorded for the first time in the Croatian part of the Adriatic Sea. In terms of biomass and abundance the dominant species were Acanthocardia tuberculata, Callista chione, Chamelea gallina, Glycymeris bimaculata, G. glycymeris, G. violascens, Laevicardium oblongum, Modiolus barbatus, Mytilus galloprovincialis, Ostrea edulis and Venus verrucosa. Statistically significant differences were noted in bivalve communities in the five main sampling areas including the island of Rab, Pag bay, Kaštela bay, Cetina estuary and Neretva estuary.Istraživanje zajednica školjkaša provedeno je tijekom 2007. i 2008. godine duž istočne obale Jadrana, od otoka Raba na sjeveru do ušća rijeke Neretve na jugu. Glavni cilj istraživanja bio je opis raspodjele i strukture zajednica školjkaša na mekim dnima duž istočne obale Jadrana, sa posebnim naglaskom na gospodarski važne vrste školjkaša u pet glavnih izlovnih područja. Hidrauličnom dredžom prikupljeno je ukupno 105 uzoraka na dubinama od 1 do 11 m. Prikupljeni školjkaši na terenu su odvojeni i zamrznuti za daljnju laboratorijsku analizu koja je uključivala identifikaciju vrsta te analizu brojnosti i biomase. U prikupljenim uzorcima 54 vrste školjkaša bile su zastupljene sa živim primjercima, dok je iz ljušturnih ostataka identificirano 87 vrsta školjkaša. Ljušture alohtone vrste školjkaša Anadara demiri zabilježene su po prvi puta u hrvatskom dijelu Jadrana. Maseno i brojčano najzastupljenije vrste bile su: Acanthocardia tuberculata, Callista chione, Chamelea gallina, Glycymeris bimaculata, G. glycymeris, G. violascens, Laevicardium oblongum, Modiolus barbatus, Mytilus galloprovincialis, Ostrea edulis i Venus verrucosa. Statistički značajna razlika zabilježena je u zajednicama školjkaša na pet glavnih područja istraživanja uključujući otok Rab, Paški zaljev, Kaštelanski zaljev te ušća rijeka Cetine i Neretve

Biometrijske karakteristike i rasprostranjenost glavoča blatara Gobius niger (Linnaeus, 1758) u Jadranskom moru

The results of biometrical analysis of ten morphometric and six meristic characters of Gobius niger were presented in this paper. Total of 301 specimen of G. niger were collected in Croatian territorial waters. Total length of all analysed specimens ranged from 70 mm to 145 mm, with mean 109.90 ± 15.64 mm. Meristic counts of analyzed black goby were D1: V-VII, D2: I+10-14, A: I+7- 12, P: 10-19, C: 14-23, V: 5. Black goby was distributed through the eastern part of Adriatic with three hot spots of population.U radu su prikazani rezultati biometrijske analize – deset morfometrijskih i šest merističkih značajki, glavoča blatara Gobius niger. Ukupno je analizirana 301 jedinka glavoča blatara koji su prikupljeni u hrvatskim teritorijalnim vodama. Ukupna dužina tijela svih analiziranih jedinki se kretala u rasponu od 70 mm do 145 mm, sa srednjom vrijednošću od 109.90±15.64 mm. Merističke značajke analiziranih jedinki glavoča blatara iznosile su D1: V-VII, D2: I + 10-14, A: I + 7-12, P: 10-19, C: 14-23, V: 5. Na temelju učestalosti pojavljivanja u analiziranim lovinama uočena su tri područja rasprostranjenja glavoča blatara na području istočnog dijela Jadranskog mora

Distribution and some biological parameters of the red gurnard, Chelidonichthys cuculus (Actinopterygii, Scorpaeniformes, Triglidae) in the north-central Adriatic Sea

Background. Red gurnard, Chelidonichthys cuculus (Linnaeus, 1758), is distributed in the Mediterranean Sea, Black Sea, and in the eastern Atlantic Ocean from Norway to Mauritania, although it is rarely found in the North Sea and on the Norwegian shelf. The aim of this work was to conduct a comprehensive study of red gurnard in the Adriatic Sea on selected aspects the population biology and some of its environmental implications . Materialsandmethods. The sampling covered the entire subdivision GSA17 (north-central Adriatic Sea) and it was based on several bottom trawl surveys of MEDITS and GRUND projects from 2000 through 2009. Biometric parameters, as well as the spatial- and depth distributions were analyzed. The parameters such as the length–weight relation, sex, gonad maturity stage, and the stomach content were determined on a subsample of 539 specimens collected seasonally (summer and autumn–winter) within 2007–2009. The data were processed statistically . Results. Chelidonichthys cuculus was mainly distributed in the central Adriatic. Juveniles showed a distribution in shallower waters while adults tended to migrate towards the Croatian coast at greater depths. The total length of the fish sampled ranged from 40 to 303 mm (TL). We assumed the length of 100 mm as a threshold separat ing juveniles from adults and the length range of 170–190 mm as the maturity size for females and males. Isometric- and allometric growth patterns were showed for the juveniles and the adults, respectively. The diet was based almost exclusively on crustaceans (IRI% > 98%) and it did not change upon reaching the sexual maturity. Chelidonichthys cuculus should be considered a specialist predator feeding mostly on necto-benthic lophogastrids (IRI% > 72%) . Conclusion. This work constitutes an attempt to summarize some environmental and biology aspects of the red gurnard in Adriatic population: differences in depth distribution and growth were found between juveniles and adults but not in diet. Males and females showed differences in growth parameters. Extending the studied area and collecting data of red gurnard in the main areas of production should help in better understanding the biolo gy and dynamics of this species

Novi nalazi crne voline Dipturus nidarosiensis (Storm, 1881) (Pisces: Rajidae) iz Jadranskoga mora

Additional records of the Norwegian skate Dipturus nidarosiensis (Storm, 1881)from the Adri-atic Sea are reported. Two specimens were collected in the southern Adriatic Pit in 2008 and 2010, respectively. The records reported herein improve our knowledge on the distribution of a rarely encountered, deep water species D. nidarosiensis, whose presence has only recently been confirmed in the Mediterranean Sea.U radu su opisani novi nalazi crne voline Dipturus nidarosiensis (Storm, 1881) iz Jadran-skoga mora. Dva primjerka ulovljena su na području Južnojadranske kotline 2008. odnosno 2010. godine. Ovi nalazi proširuju saznanja o distribuciji ove rijetke dubokomorske vrste čija je prisutnost u Sredozemnom moru tek nedavno utvrđena

Upoznavanje značajki reproduktivne biologije, morfometrije i starosti vrste Chtenopteryx sicula (Cephalopoda: Chtenopterygidae) u Jadranu

The first record of the deep-sea species Chtenopteryx sicula is reported from the Adriatic Sea. Atotal of six specimens of this rare species were caught, with bottom trawl and pelagic trawl nets, in the scope of the Deep Sea Research of the bathyal fauna in the South Adriatic Pit in 2008 and 2010. Specimens were caught at depths down to 1200 m, therefore making it the deepest and northernmost finding of this species in the Mediterranean Sea. The dorsal mantle lengths of analyzed specimens ranged between 21 and 60 mm. Only in females, a visceral photophore on the ventral side of the inc sac was detected. Some new information on morphometric body and beak features was given in the paper, including the description of beak pigmentation. A number of increments in statoliths revealed that individuals were between three and five months old. A positive linear correlation between the length of statoliths and number of increments/age in days was detected. Macroscopic and histological samples of gonads proved that one specimen was sexually mature (August), four specimens were in stages of sexual maturation (May and August) and two were immature (March). The results indicated that the maturation process of the species in the South Adriatic Sea starts in spring and the full sexual maturity is reached during summer.U radu su opisani prvi nalazi dubokomorske vrste Chtenopteryx sicula u Jadranskom moru. Pridnenom i pelagičnom mrežom ulovljeno je ukupno šest primjeraka ove rijetke vrste u sklopu istraživanja dubokomorskih zajednica u južnojadranskoj kotlini 2008 i 2010. godine. Primjerci su ulovljeni na dubinama do 1200 m te predstavljaju najdublji i ujedno najsjeverniji nalaz ove vrste u Mediteranu. Dorzalna dužina plašta analiziranih jedinki kretala se od 21 do 60 mm. Samo u ženki nađeni su visceralni fotofori na ventralnoj strani vrećice sa crnilom. U radu su date nove informacije vezane uz obilježja kljuna, uključujući detaljan opis pigmentacije. Broj zona prirasta u statolitima ukazuje na starost jedinki između tri i pet mjeseci. Utvrđena je pozitivna korelacija između dužine statolita i broja zoni prirasta/starosti u danima. Makroskopski i histološki uzorci gonada potvrdili su da je jedna jedinka bila spolno zrela (kolovoz), četiri jedinke su bile u stadiju spolnog sazrijevanja (svibanj i kolovoz), a dvije su bile spolno nezrele (ožujak). Rezultati ukazuju na to da proces spolnog sazrijevanja ove vrste u južnom Jadranu počinje u proljeće, dok se puna spolna zrelost doseže tijekom ljeta

Distribution and Population Structure of Greater Weever, Trachinus draco (Linnaeus, 1758.), in the Northern and Central Adriatic Sea

This study describes the distribution patterns and population structure of greater weever in the Adriatic Sea. Biological data were obtained during MEDITS surveys in the spring-summer period. The aim of this study is to provide recent data for better understanding of species biology and to create basis for fisheries management based on ecological approach