Biometrija, dužinsko-dužinski i dužinsko-maseni odnosi juvenilne i adultne palamide, Sarda sarda (Bloch, 1793), u istočnom srednjem Jadranu

This paper presents some biological features of juvenile and adult specimens of Atlantic bonito, Sarda sarda (Bloch, 1793), in the eastern middle Adriatic Sea. A total of 194 specimens were analysed, of which 93 were juveniles and 101 were adults. Juvenile individuals ranged from 5.7 to 8.4 cm while adults ranged from 39.3 to 56.7 cm. In order to analyse biometry, nine morphometric characters were analysed. Length-length equations for overall converted body lengths of fish were linear. Comparison of length-length relationships between juvenile and adult specimens showed statistically significant differences in almost all morphometric characteristics, except for the fork length–second dorsal fin base. Females insignificantly prevailed in adults. Overall gonads were in post-spawning state. Juveniles were unsexed. Length-weight relationships of juveniles and adults were W = 0.0033LF3.424 and W = 0.0149LF2.984, respectively.U radu su analizirani juvenilni i adultni primjerci palamide, Sarda sarda (Bloch, 1793), prikupljeni na području istočnog dijela srednjeg Jadranskog mora. Ukupno je obrađeno 194 primjerka, od čega je 93 juvenilnih i 101 adultni. Analizom biometrijskih svojstava zabilježene su promjene morfometrijskih odnosa s porastom vilične dužine (LF), te je utvrđeno da postoji statistički značajna razlika između morfometrijskih odnosa juvenilnih i adultnih primjeraka palamide, osim kod odnosa LF-LD2. Spol je bilo moguće odrediti samo kod adultnih primjeraka, gdje su brojčano neznatno dominirale ženke. Analizom stanja gonada utvrđeno je da su se svi adultni primjerci izmrijestili. Kod juvenilnih primjeraka dužinsko–masenim odnosom je utvrđena pozitivna alometrija (b = 3.424), dok je kod adultnih primjeraka utvrđena izometrija (b = 2.984)

Usporedba dužinske raspodjele srdele goleme (Sardinella aurita) iz obalnog i otvorenog mora istočnog dijela srednjeg Jadrana

Round sardinella, Sardinella aurita specimens (N= 2,033) were caught in inshore (Virsko more) and offshore waters (Dugi otok) of the eastern middle Adriatic Sea by commercial purse seine, monthly from November 2007 to January 2009. Out of all specimens, 983 were male (48.4%), 1,021 were female (50.2%) and 29 (1.4%) were undetermined specimens, giving an overall sex ratio of m/ f=0.96. Round sardinella specimens from inshore waters (N=526) and offshore waters (N=1,507) showed total length (LT) range 13.0-32.5 cm and 10.0-30.0 cm, respectively. In total, they showed positive allometry (b=3.2266). Fulton’s mean condition factor for round sardinella from inshore waters was K =0.76 ± 0.23, and for samples from offshore waters, it was K =0.73 ± 0.05. Females indicated better condition ( K =0.75 ± 0.05) in both analyzed areas than males ( K =0.74 ± 0.05).U radu se uspoređuje dužinski sastav, dužinsko maseni odnos i kondicija srdele goleme Sardinella aurita iz obalnog (virsko more) i otvorenog (Dugi otok) mora istočnog dijela srednjeg Jadrana. u svrhu navedenih istraživanja su korišteni mjesečni uzorci iz lovina plivarice ostvarenih tijekom razdoblja studeni 2007.- siječanj 2009. god. ukupno je analizirano 2 033 jedinki, od čega 983 mužjaka, 1021 ženka i 29 jedinki kojima nije bilo moguće odrediti spol. odnos spolova je iznosio m/ž=0,96. totalne dužine (LT) jedinki iz uzoraka lovina obalnog mora (N=526) su kolebale od 13,0 do 32,5 cm, te od 10,0 do 30,0 cm kod jedinki iz otvorenog mora (N=1507). ukupno su jedinke pokazale pozitivan alometrijski rast (b=3,2266). kubični faktor kondicije (K) je za jedinke iz obalnog mora iznosio K =0,76 ± 0,23 a za srdelu golemu s područja otvorenog mora je bio K=0,73 ± 0,05. Ženke su pokazale bolju kondiciju ( K =0,75 ± 0,05) od mužjaka ( K =0,74 ± 0,05) u oba analizirana područja

MORFOMETRIJSKA I MERISTIČKA OBILJEŽJA SRDELE (Sardina pilchardus, Walbaum, 1792.) IZ ZADARSKOGA RIBOLOVNOG PODRUČJA

This paper presents the results of some morphometric and meristic parameters of sardine, Sardina pilchardus (Walbaum, 1792) from coastal (Virsko more) and open waters (Dugi Otok) of the Zadar area, during the period from March 2004 to February 2005. The total length of all analyzed specimens ranged from 13.0 to 19.0 cm and weights ranged between 16.72 g and 51.45 g, respectively. Body length analysis indicated greater values for sardine females (N=541) than males (N=668) in all observed lengths (LT, LF, LS, LA, LH, OK, LP and BD), except for the eye diameter (ED), where both sexes had equal average value. The length–weight relationship indicated negative allometric growth (b=2.5538, a=0.0261). In length–length relationships, statistical significance occurred in the following relationships: eye diameter in head length (2.78%) and head length in total length (9.01%). For vertebrae analysis, two groups were compared according to their length: the first one obtained specimens smaller than 16.0 cm in total length (LT), whereas samples longer than 16.0 cm belonged to the second group. The number of vertebrae in both groups ranged between 48 and 52 with the most abundant vertebrae class of 50 vertebrae (37.7 %), whereas a minimal number of sardines (4.9 %) had 48 vertebras. A statistically significant difference between the two analyzed groups was not found (t=0.86). The number of rays (RD) in the dorsal fin ranged from 17 to 19 and the average value was 18.11 ± 0.51.U ovom su radu prikazane neke morfometrijske i merističke značajke srdele Sardina pilchardus (Walbaum, 1792.) iz obalnog (Virsko more) i otvorenog (Dugi otok) mora zadarskog područja tijekom razdoblja od ožujka 2004. do veljače 2005. Totalna dužina (LT) svih analiziranih jedinki varirala je od 13,0 do 19,0 cm, a težine su bile u rasponu od 16,72 do 51,45 g. Ženke (N=541) su pokazale veće dužine od mužjaka (N=668) u svim analiziranim tjelesnim dimenzijama (LT, LF, LS, LA, LH, OK, LP i BD), osim kod promjera oka (ED), gdje su vrijednosti u oba spola bile izjednačene. Utvrđen je negativan alometrijski rast srdele (b = 2,5538, a = 0,0261). U dužinsko–dužinskim odnosima zabilježena je statistički značajna razlika između spolova pri odnosu promjera oka i dužine glave (t = 2,78), te dužine glave u totalnoj dužini tijela (t = 9,01). Za analizu broja kralježaka ribe su podijeljene u dvije grupe: prva je sadržavala jedinke totalnih dužina manjih od 16,0 cm, a u drugoj su grupi bile ribe veće od 16,0 cm. Broj je kralježaka u obje skupine varirao od 48 do 52, s modalnim razredom od 50 kralježaka (37,7%), dok je samo 4,9% jedinki srdele imalo 48 kralježaka. Nije utvrđena statistički značajna razlika između dviju promatranih skupina (t = 0,86). Broj šipčica na leđnoj peraji kolebao je od 17 do 19, sa srednjom vrijednošću od 18,11 ± 0,51

Oogenesis and spermatogenesis in round sardinella (Sardinella aurita Valenciennes, 1847) from the eastern part of the Adriatic Sea

Background and purpose: Small pelagic fish species round sardinella (Sardinella aurita) has expanded its habitat during the last few decades towards colder parts of the Mediterranean Sea. In the Adriatic Sea, this investigation is the first attempt to study its gonad development histologically.Materials and methods: S. aurita specimens were sampled monthly from commercial landings of purse seine catches from the eastern part of the Adriatic Sea from November 2007 to January 2009. After biometric parameters were determined, gonads were removed from the fish and weighed. Sex and gonad development were determined macroscopically by the shape and the structure of gonads and afterwards gonads were analysed histologically.Results: The phases of gonadal development of both sexes of S. aurita were: immature, developing, spawning capable, regressing, and regenerating. An annual reproduction cycle based on gamete development revealed five stages of oocyte development: chromatin nucleolar stage, perinucleolar stage, yolk vesicle (cortical alveoli) formation, vitellogenic (yolk) stage, and ripe (mature) stage. Spermatogenesis was described through three stages: spermatocytogenesis (formation of primary spermatocytes from spermatogonia), meiosis (formation of secondary spermatocytes and spermatids) and spermiogenesis.Conclusions: Gonadal histology analyses of both sex of S. aurita indicated summer spawning manner of this species, with a peak in June-August period

Usporedba dužinske raspodjele srdele goleme (Sardinella aurita) iz obalnog i otvorenog mora istočnog dijela srednjeg Jadrana

Round sardinella, Sardinella aurita specimens (N= 2,033) were caught in inshore (Virsko more) and offshore waters (Dugi otok) of the eastern middle Adriatic Sea by commercial purse seine, monthly from November 2007 to January 2009. Out of all specimens, 983 were male (48.4%), 1,021 were female (50.2%) and 29 (1.4%) were undetermined specimens, giving an overall sex ratio of m/ f=0.96. Round sardinella specimens from inshore waters (N=526) and offshore waters (N=1,507) showed total length (LT) range 13.0-32.5 cm and 10.0-30.0 cm, respectively. In total, they showed positive allometry (b=3.2266). Fulton’s mean condition factor for round sardinella from inshore waters was K =0.76 ± 0.23, and for samples from offshore waters, it was K =0.73 ± 0.05. Females indicated better condition ( K =0.75 ± 0.05) in both analyzed areas than males ( K =0.74 ± 0.05).U radu se uspoređuje dužinski sastav, dužinsko maseni odnos i kondicija srdele goleme Sardinella aurita iz obalnog (virsko more) i otvorenog (Dugi otok) mora istočnog dijela srednjeg Jadrana. u svrhu navedenih istraživanja su korišteni mjesečni uzorci iz lovina plivarice ostvarenih tijekom razdoblja studeni 2007.- siječanj 2009. god. ukupno je analizirano 2 033 jedinki, od čega 983 mužjaka, 1021 ženka i 29 jedinki kojima nije bilo moguće odrediti spol. odnos spolova je iznosio m/ž=0,96. totalne dužine (LT) jedinki iz uzoraka lovina obalnog mora (N=526) su kolebale od 13,0 do 32,5 cm, te od 10,0 do 30,0 cm kod jedinki iz otvorenog mora (N=1507). ukupno su jedinke pokazale pozitivan alometrijski rast (b=3,2266). kubični faktor kondicije (K) je za jedinke iz obalnog mora iznosio K =0,76 ± 0,23 a za srdelu golemu s područja otvorenog mora je bio K=0,73 ± 0,05. Ženke su pokazale bolju kondiciju ( K =0,75 ± 0,05) od mužjaka ( K =0,74 ± 0,05) u oba analizirana područja

MORFOMETRIJSKA I MERISTIČKA OBILJEŽJA SRDELE (Sardina pilchardus, Walbaum, 1792.) IZ ZADARSKOGA RIBOLOVNOG PODRUČJA

This paper presents the results of some morphometric and meristic parameters of sardine, Sardina pilchardus (Walbaum, 1792) from coastal (Virsko more) and open waters (Dugi Otok) of the Zadar area, during the period from March 2004 to February 2005. The total length of all analyzed specimens ranged from 13.0 to 19.0 cm and weights ranged between 16.72 g and 51.45 g, respectively. Body length analysis indicated greater values for sardine females (N=541) than males (N=668) in all observed lengths (LT, LF, LS, LA, LH, OK, LP and BD), except for the eye diameter (ED), where both sexes had equal average value. The length–weight relationship indicated negative allometric growth (b=2.5538, a=0.0261). In length–length relationships, statistical significance occurred in the following relationships: eye diameter in head length (2.78%) and head length in total length (9.01%). For vertebrae analysis, two groups were compared according to their length: the first one obtained specimens smaller than 16.0 cm in total length (LT), whereas samples longer than 16.0 cm belonged to the second group. The number of vertebrae in both groups ranged between 48 and 52 with the most abundant vertebrae class of 50 vertebrae (37.7 %), whereas a minimal number of sardines (4.9 %) had 48 vertebras. A statistically significant difference between the two analyzed groups was not found (t=0.86). The number of rays (RD) in the dorsal fin ranged from 17 to 19 and the average value was 18.11 ± 0.51.U ovom su radu prikazane neke morfometrijske i merističke značajke srdele Sardina pilchardus (Walbaum, 1792.) iz obalnog (Virsko more) i otvorenog (Dugi otok) mora zadarskog područja tijekom razdoblja od ožujka 2004. do veljače 2005. Totalna dužina (LT) svih analiziranih jedinki varirala je od 13,0 do 19,0 cm, a težine su bile u rasponu od 16,72 do 51,45 g. Ženke (N=541) su pokazale veće dužine od mužjaka (N=668) u svim analiziranim tjelesnim dimenzijama (LT, LF, LS, LA, LH, OK, LP i BD), osim kod promjera oka (ED), gdje su vrijednosti u oba spola bile izjednačene. Utvrđen je negativan alometrijski rast srdele (b = 2,5538, a = 0,0261). U dužinsko–dužinskim odnosima zabilježena je statistički značajna razlika između spolova pri odnosu promjera oka i dužine glave (t = 2,78), te dužine glave u totalnoj dužini tijela (t = 9,01). Za analizu broja kralježaka ribe su podijeljene u dvije grupe: prva je sadržavala jedinke totalnih dužina manjih od 16,0 cm, a u drugoj su grupi bile ribe veće od 16,0 cm. Broj je kralježaka u obje skupine varirao od 48 do 52, s modalnim razredom od 50 kralježaka (37,7%), dok je samo 4,9% jedinki srdele imalo 48 kralježaka. Nije utvrđena statistički značajna razlika između dviju promatranih skupina (t = 0,86). Broj šipčica na leđnoj peraji kolebao je od 17 do 19, sa srednjom vrijednošću od 18,11 ± 0,51

Biometrija, dužinsko-dužinski i dužinsko-maseni odnosi juvenilne i adultne palamide, Sarda sarda (Bloch, 1793), u istočnom srednjem Jadranu

This paper presents some biological features of juvenile and adult specimens of Atlantic bonito, Sarda sarda (Bloch, 1793), in the eastern middle Adriatic Sea. A total of 194 specimens were analysed, of which 93 were juveniles and 101 were adults. Juvenile individuals ranged from 5.7 to 8.4 cm while adults ranged from 39.3 to 56.7 cm. In order to analyse biometry, nine morphometric characters were analysed. Length-length equations for overall converted body lengths of fish were linear. Comparison of length-length relationships between juvenile and adult specimens showed statistically significant differences in almost all morphometric characteristics, except for the fork length–second dorsal fin base. Females insignificantly prevailed in adults. Overall gonads were in post-spawning state. Juveniles were unsexed. Length-weight relationships of juveniles and adults were W = 0.0033LF3.424 and W = 0.0149LF2.984, respectively.U radu su analizirani juvenilni i adultni primjerci palamide, Sarda sarda (Bloch, 1793), prikupljeni na području istočnog dijela srednjeg Jadranskog mora. Ukupno je obrađeno 194 primjerka, od čega je 93 juvenilnih i 101 adultni. Analizom biometrijskih svojstava zabilježene su promjene morfometrijskih odnosa s porastom vilične dužine (LF), te je utvrđeno da postoji statistički značajna razlika između morfometrijskih odnosa juvenilnih i adultnih primjeraka palamide, osim kod odnosa LF-LD2. Spol je bilo moguće odrediti samo kod adultnih primjeraka, gdje su brojčano neznatno dominirale ženke. Analizom stanja gonada utvrđeno je da su se svi adultni primjerci izmrijestili. Kod juvenilnih primjeraka dužinsko–masenim odnosom je utvrđena pozitivna alometrija (b = 3.424), dok je kod adultnih primjeraka utvrđena izometrija (b = 2.984)

EXPLOITATION AND MORTALITY OF GILT SARDINE SARDINELLA AURITA, VALENCIENNES, 1847 IN THE MIDDLE EASTERN ADRIATIC SEA

U ovom su radu prikazani rezultati istraživanja strukture populacije, mortaliteta i iskorištavanja srdele goleme Sardinella aurita, Valenciennes, 1847. iz uzoraka lovina ostvarenih u obalnom (Virsko more) i otvorenom moru (Dugi otok) zadarskog područja, u razdoblju od studenog 2007. do siječnja 2009. Ukupno su analizirane 2033 jedinke, od čega 983 mužjaka, 1021 ženka i 29 jedinki kojima nije bilo moguće odrediti spol. Odnos spolova je iznosio m/ž=0,96 u korist ženki. Totalne dužine (TL) svih analiziranih jedinki su se kretale od 10,0 do 32,5 cm, a srednja vrijednost je iznosila 22,0 ± 3,65 cm. Dob je varirala od prve godine (0+) do navršenih pet godina života (5+). Vrijednosti koeficijenta prirodne (M), ribolovne (F) i ukupne smrtnosti (Z), te indeksa preživljavanja (S) populacije su iznosile: M=0,46; F=0,23; Z=0,69 i S=0,60. Iako se na hrvatskom dijelu Jadranskog mora još uvijek statistički ne evidentira ulov srdele goleme, u svjetskim morima i oceanima su kroz posljednje desetljeće ukupni godišnji ulovi ove vrste bili na razini od oko 500 000 t.This paper presents the results of population structure, mortality and exploitation of gilt sardine Sardinella aurita, Valenciennes 1847, from the catches of inshore (Virsko more) and offshore waters (Dugi otok) in the Zadar area between November 2007 and January 2009. A total of 2033 specimens (983 male, 1021 female, 29 undetermined) showed the sex ratio m/f=0.96; females predominated. The total length (TL) of all observed specimens varied from 10.0 to 32.5 cm (mean±SD=22.0 ± 3.65 cm). The age of gilt sardine varied from 0+ to 5+. The values of natural (M), fishing (F), total mortality (Z) and survival rate (S) coefficients were M=0.46, F=0.23, Z=0.69 and S=0.60, respectively. Even though the catches of gilt sardine have not been recorded yet for the Croatian part of the Adriatic Sea, as far as the world’s seas and oceans are concerned, the total catches were ca. 500 000 t in the last decade

Reproductive period and histological analysis of the painted comber, Serranus scriba (Linnaeus, 1758), in the Trogir Bay area (eastern mid-Adriatic)

A total of 798 specimens of the painted comber, Serranus scriba(Linnaeus, 1758), were caught in Trogir Bay (eastern mid-Adriatic) from June 2001 to May 2002 and analyzed. Total length ranged 7.1-20.0 cm (mean 11.0±1.7 cm); body weight ranged 4.21-108.99 g (mean 18.59±10.248 g). Histological analysis of 242 specimens confirmed simultaneous hermaphroditism. The annual variation of gonadosomatic index indicates that S. scriba spawns rom May to August. Descriptions based on microscopic examinations of ovarian and testicular tissues are given

Reproduction, length-weight relationship and condition of sardine, Sardina pilchardus (Walbaum, 1792), in the eastern Middle Adriatic Sea (Croatia)

Background and Purpose: The reproductive cycle of sardine, Sardina pilchardus (Walb.), from offshore (Dugi otok) and inshore waters (Virsko more) of Mid Adriatic Sea was studied to gain information on spawning period, sex ratio, length-weight relationship and condition of this most commercially important fish species in the Adriatic Sea. Materials and Methods: A total of 1,219 sardine specimens were collected from monthly random samples of purse seine catches realized in the Mid Adriatic Sea during the March 2004 – February 2005 period. Fish were measured and weighed. Sex was determined and gonad maturity stage was assessed. Gonadosomatic index (GSI) was calculated by expressing the monthly gonad weight as a proportion of the total body weight. The length (LT)–weight (W) relationship was determined (logW=log a+b log LT) as well as the monthly fish condition, using Fulton’s equation (K=100 W/ LT 3). Results and Conclusions: The total length of sardine ranged from 13.0 to 19.0 cm and the mass ranged from 16.72 to 51.45 g. Sex ratio was different from 1:1; males predominated (a/b=1.2). The reproductive activity period was from October to May, coinciding with the most developed stages of gonads as well as with the highest gonad weights and gonadosomatic indices. The length-weight relationship of sardine was described by the expression: W=0.026 LT2.5538 (r2=0.697). Fulton’s condition factor showed greater values in sardine samples from the inshore waters (Virsko more, K=0.8205) than those from the offshore waters (Dugi Otok,K=0.7317)