scholarly journals Age, Growth and Reproduction of Coryphaena hippurus (Linnaeus, 1758) in Maltese Waters, Central Mediterranean

2015 ◽  
Vol 16 (2) ◽  
pp. 334 ◽  
Author(s):  
M. GATT ◽  
M. DIMECH ◽  
P. J. SCHEMBRI

Age, growth and reproduction of the dolphinfish Coryphaena hippurus Linnaeus, 1758 collected from the Central Mediterranean in the period 2004-2010 by the traditional Maltese fish aggregating devices (FAD) and surface longline fisheries were studied. The a and b parameters of the length-weight relationship for fish 11-142 cm fork length (FL) (n = 4042) were determined as a = 0.018 and 0.022 with b = 2.85 and 2.79, for males and females respectively. The counting of annual increments from dorsal spines of >65 cm FL dolphinfish at X25 magnification (n = 47) permitting an age reading resolution in years  , and the counting of daily increments from sagittal otoliths of <65 cm FL dolphinfish at X400 magnification (n = 583) permitting an age reading resolution in days, were estimated; the von Bertalanffy growth model applied to these fish gave the following parameters: L∞ = 107.8 cm FL and 120.2 cm FL, and K = 1.9 yr-1 and 1.56 yr-1, for males and females respectively. The maximum age observed was 2 years. Size at 50% maturity for fish 10-131 cm FL (n = 1376) was 58.9 cm FL and 62.5 cm FL for males and females, respectively. The sex ratio for the fish sampled from the FAD fishery (10.5-131 cm FL) was 1:1.54 (M:F) and for dolphinfish sampled from the surface longline fishery (91-130 cm FL) was 1:0.76 (M:F).  Back-calculated hatch dates from age-0 dolphinfish (n = 518) suggested that spawning occurs from June to September with the highest levels in June. This study is the first to use dorsal spines to determine the age of adult dolphinfish.

2017 ◽  
Vol 68 (10) ◽  
pp. 1912 ◽  
Author(s):  
Ozlem Ablak Gurbuz

An increase in aquaculture production may have positive effects on both food resources and a country’s economy. Carp (Cyprinus carpio L.) is the most common cyprinid species in Turkey and accounts for approximately one-fifth of total inland water aquaculture production. However, carp production in Turkey has decreased in recent years. Changes in carp population of Hirfanli Dam were compared with previous studies in similar and different habitats worldwide. The population structure, growth and reproduction of carp were investigated. The length–weight relationships for the carp population of Hirfanli Dam indicated negative allometric growth in males and females, but the condition factor was greater for these carp than carp elsewhere. Asymptotic length and the growth coefficient were 89.42cm and 0.071year–1. Fecundity was positively correlated with fork length, total weight, gonad weight and age. The carp population of Hirfanli Dam evaluated in the present study appeared to have a lower fecundity and smaller egg diameter compared with other carp populations.


1972 ◽  
Vol 29 (7) ◽  
pp. 1079-1081
Author(s):  
J. I. Manzer

The length–weight relationship for 298 pomfret (Brama japonica) ranging in fork length from 30 to 49 cm, and caught in 1956 and 1957 in the Gulf of Alaska by gillnets varying in mesh size from [Formula: see text] (63 mm) to [Formula: see text] inches (133 mm) was examined. Covariance analysis of the data indicated that within years the length–weight relationship did not differ between males and females; and, on the average, both males and females of a particular length were significantly heavier in 1956 than in 1957. Allometric equations for each year based on data for sexes combined are considered more appropriate than a single equation based on pooled data. The equations relating weight in kilograms to length in centimeters, for 1956 and 1957, respectively, are[Formula: see text]and apply to the lower third of the known size range for pomfret in the Gulf of Alaska.


2016 ◽  
Vol 67 (5) ◽  
pp. 578 ◽  
Author(s):  
Sondes Marouani ◽  
Hasna Kadri ◽  
Mohamed Nejmeddine Bradai

The occurrence of the piked spurdog (Squalus megalops) in the Gulf of Gabès (Tunisia, central Mediterranean Sea) was recently confirmed. The present study is the first to report the age, growth, longevity, natural mortality and size and age at maturity of this species in the Mediterranean Sea, precisely in the Gulf of Gabès. Marginal increment and edge analysis suggested annual band formation. Age estimates ranged from 0 to 26 and from 0 to 29 years for males and females respectively. Von Bertalanffy growth parameters derived from length-at-age data were: the theoretical asymptotic length L∞=82.31±1.55cm, the growth-rate coefficient k=0.06±0.003 years–1, the theoretical age at length zero t0=–3.89±0.25 years for females; and L∞=68.55±0.98cm, k=0.08±0.003 years–1, t0=–4.65±0.25 years for males. Males and females reached maturity at 44.36- and 56.41-cm total length, corresponding to 8.39 and 15.38 years respectively. Longevity estimates were 32.85 and 46.11 years for males and females respectively. On the basis of life-history parameters, natural mortality estimation M ranged from 0.14 to 0.17.


2021 ◽  
Vol 38 (3) ◽  
pp. 293-302
Author(s):  
Ataman Altuğ Atıcı ◽  
Ahmet Sepil ◽  
Fazıl Şen ◽  
Asude Çavuş

In this study, the growth and reproductive characteristics of Capoeta kosswigi Karaman, 1969 and Barbus ercisianus Karaman, 1971, which are endemic to the Lake Van Basin, in Deliçay (Van) were investigated. A total of 309 C. kosswigi and 288 B. ercisianus specimens were caught by electrofishing between April and August 2018. The fork length of C. kosswigi and B. ercisianus ranged from 3.7-26.1 cm and from 4.3-22.7 cm, and the total weights ranged from 0.6-227.4 g and from 1.2-140.0 g, respectively. The most intensive catching was in C. kosswigi population of 5.0-6.9 (27.5%) cm and 0-19.9 (67.0%) g in the groups, and 12.0-13.9 (24.7%) cm and 0-9.9 (23.3%) g groups in B. ercisianus. Condition factor was determined as 1.305±0.008 (0.798-1.886) in C. kosswigi and 1.158±0.006 (0.864-1.559) in B. ercisianus. The length-weight relationships were calculated as W = 0.01435 × L2.952 (r2 = 0.996) for C. kosswigi and W = 0.01276 × L2.959 (r2 = 0.994) for B. ercisianus. The M:F ratio was calculated as 1:0.15 in C. kosswigi and 1:0.64 in B. ercisianus. It was established that C. kosswigi attained sexual maturity when they reached to 11 cm fork length for males, 18 cm fork length for females. Maturation of B.ercisianus individuals occurred at 9 cm fork length in males and 12 cm fork length in females. The spawning in C. kosswigi was observed from 1st week of May to 2nd week of July, and in B. ercisianus from 1st week of May to 1st week of August. It may be suggested that minimum catching size must be 20 cm fork length for C. kosswigi and 15 cm fork length for B. ercisianus.


Author(s):  
Iin Ika Wahyuni ◽  
Anhar Solichin ◽  
Suradi Wijaya Saputra

 Salah satu potensi perikanan di perairan Brebes dan Tegal adalah Udang Putih yang terancam kelestariannya akibat meningkatnya penangkapan dengan Jaring Arad. Tujuan penelitian ini untuk mengetahui aspek biologi udang P. indicus dan status sumberdayanya, seperti komposisi hasil tangkapan, struktur ukuran, sifat pertumbuhan, dan aspek reproduksi. Metode penelitian yang digunakan yaitu metode survei. Sampel udang diambil 100% dari total hasil tangkapan tiap perahu karena hasil tangkapan kurang dari 100 ekor. Pengambilan sampel enam kali dari Juli-Desember 2016. Tempat pengambilan sampel di TPI Kluwut, Kaliwlingi, Larangan dan Surodadi. Hasil penelitian nilai L50%P. indicus di sebelah utara Brebes dan Tegal memiliki panjang total 84 mm dan 85 mm, nilai ½ L∞ yaitu 97 mm (jantan) dan 121 mm (betina). L50% < ½ L∞ berarti ukuran udang yang tertangkap masih kecil sehingga dikhawatirkan terjadinya growth overfishing. Sifat pertumbuhan udang jantan dan betina di Brebes yaitu isometrik (b=2,98) dan alometrik negatif (b=2,86), di Tegal yaitu alometrik positif (b= 3,43) dan isometrik (b= 3,02). Nilai faktor kondisi P. indicus di Brebes 1,63 (jantan) dan 1,59 (betina), sedangkan di Tegal 1,81 (jantan) dan 1,57 (betina). Perbandingan nisbah kelamin P. indicus di Brebes 1: 4,4 dan di Tegal 1: 2,9. Status tingkat pemanfaatan sumberdaya udang P. indicus di sebelah utara Brebes dan Tegal perlu penyempurnaan untuk memenuhi syarat perikanan yang berkelanjutan. One of the potential fishery in the Brebes and Tegal waters is P. Indicus shrimp that has been threatened by increasing fishing effort of Arad net. The purpose of this research to know biological aspects of P. indicus and resources status, such as composition of catch, size of structure, growth, and reproduction aspects. The method used is survey method. Shrimp samples were taken at random 10% of the total catch per boat. Sampling six times from July to December 2016. The sampling at TPI Kluwut, TPI Kaliwlingi, TPI Larangan and TPI Surodadi. The results of research L50% value of P. indicus in north Brebes and Tegal has 84 mm and 85 mm TL, ½ L∞ are 97 mm (males) and 121 mm (females). L50% <½ L∞ mean size of shrimp caught are ssmall to worry about the occurrence of growth overfishing. The growth of males and females shrimp in Brebes are isometric (b = 2.98) and negative allometric (b = 2.86), in Tegal growth of males and females are positive allometrik (b = 3.43) and isometric (b = 3.02). Condition factor P. indicus in Brebes are 1.63 (males) and 1.59 (females), whereas in Tegal are 1.81 (males) and 1.57 (females). Sex ratio P. indicus in Brebes 1: 4.4 and in Tegal 1: 2.9. Status of the level of resource P. indicus need improvement to qualify sustainable fisheries.  


1999 ◽  
Vol 79 (6) ◽  
pp. 1091-1096 ◽  
Author(s):  
Alexander Arkhipkin ◽  
Patrizia Jereb ◽  
Sergio Ragonese

Microstructural prominent discontinuities (checks) were observed within the statoliths of the short-finned squid Illex coindetii from the Strait of Sicily. Two hundred and forty-two pairs of statoliths were extracted from specimens (52–175 mm of mantle length, ML) sampled during autumn 1995 and analysed. Beside the check delimiting the postnuclear zone, up to four peripheral checks were detected in the peripheral zone. The occurrence of peripheral checks in the statoliths of immature squid was low (5–15%), whereas 80–95% of mature squid had peripheral checks. The mean number of peripheral checks within statoliths of mature males and females did not differ significantly (1.53–1.68 peripheral checks per squid). In mature and spawning females, the number of peripheral checks corresponded well with the number of spermatophoric bundles inside the mantles. Age at peripheral check formation was estimated for each sex, indicating that the first peripheral check formed at a significantly younger age in males than in females. Formation of the first peripheral check coincided with the start of maturation in both sexes, at a wide age range. The number of increments between peripheral checks subsequent to the first one declined sharply and remained similar in the two sexes, with a predominant mode between three and seven increments. A possible relationship between the number of peripheral checks and mating events in I. coindetii is discussed.


2003 ◽  
Vol 60 (2) ◽  
pp. 259-267 ◽  
Author(s):  
B Guyonnet ◽  
C Aliaume ◽  
J.-J Albaret ◽  
C Casellas ◽  
A Zerbi ◽  
...  

Abstract The biology of the clupeid Ethmalosa fimbriata (Bowdich) was studied as a potential bio-indicator of pollution in three bays of the Ebrie Lagoon, an inter-tropical lagoon in the Ivory Coast (western Africa). Bietri Bay was the most impacted by Abidjan's industrial and urban waste, Cocody Bay was characterized by the presence of eutrophic water, and Sud Boulay Bay, located in a rural zone, was least impacted. Sizes at first maturity (fork length) of E. fimbriata were lowest in the most polluted bay (Bietri: 80.8 and 83.5 mm for males and females, respectively), higher in the intermediately polluted bay (Cocody: 125 and 137.5 mm, respectively), and highest in the unpolluted bay (Sud Boulay: 135 and 145 mm, respectively). Owing to its hardiness, E. fimbriata is the dominant species in polluted water, constituting more than 75% of the total number of fish caught. As a consequence, fish diversity decreased and the community was less structured in the polluted environment than in the unpolluted one.


1968 ◽  
Vol 25 (10) ◽  
pp. 2091-2100 ◽  
Author(s):  
S. U. Qadri

In Lac la Ronge the lake whitefish (Coregonus clupeaformis (Mitchill)) spawned from late October until the middle of November at ages of 8 years and over. The growing season lasted from late May to early October and young fish grew faster than older ones and tended to have a longer growing season. Ages for 1604 fish taken during 4 years showed that they grew to a fork length of about 16 inches in 10 years, the rate being slower than for lake whitefish in other large lakes in North America. The length-weight relationships were linear: for the open lake, log W = 3.48 log L – 3.93, and for Hunter Bay, log W = 3.26 log L – 3.66. The males matured a little earlier than females and their life span was somewhat shorter. The sex ratio was approximately 1:1.


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