scholarly journals Growth characteristics of the European hake, Merluccius merluccius (Linnaeus, 1758), inhabiting northeastern Mediterranean

2020 ◽  
Vol 61 (1) ◽  
pp. 79-88
Author(s):  
Hulya Girgin ◽  
Nuri Başusta

In this study, the age and some growth characteristics of the European hake, Merluccius merluccius, from the northeastern Mediterranean were examined during 2015-2016 fishing season. A total of 661 European hake ranging from 9.8 to 51.6 cm in total length was captured by commercial trawler. Female/male ratio was 1/1.15. Age determination was conducted using the sagittal otoliths. Ages of examined individuals ranged from 1 to 7 years. The von Bertalanffy growth parameters fitted to the average measured total lengths-at-age for each sex separately and estimated as L∞= 93.98 cm, k= 0.114 year-1, t0= -0.597 year for females, as L∞= 77.65 cm , k= 0.153 year-1, t0= -0.343 year for males and as L∞= 84.44 cm, k= 0.135 year-1, t0= -0.469 year for combined sexes. The growth performance value (Φ) of the European hake population was computed as 2.98 for combined sexes. Mean condition factor value for population was 0.654±0.021; the highest condition factor was found as 1.01 in fish at age 7.

2020 ◽  
Vol 15 (4) ◽  
pp. 121-133
Author(s):  
Ebru İfakat Özcan

In this study, some growth features have been investigated like sex distribution, length and weight relationship, age determination, von Bertalanffy growth parameters and condition factor of population Acanthobrama marmid Heckel, 1843 in Pülümür River. 276 samples examined during the study consisted of 157 females and 119 males and the female/male ratio was calculated as 1/0.758. It was determined that the total length and weight values varied between 7.8-21.1cm and 5.6-121.21 g in all individuals. The population has showed distribution between I-V age groups. Length-weight equation in were determined as W=0.0063L3.248 (R2=0.960) in females, W=0.0062L3.252 (R2=0.958) in males and W=0.0063L3.249 (R2=0.959) in all individuals. Positive allometric growth was observed for both sexes due to the “b” values were statistically different from 3. The von Bertalanffy growth equations were determined Lt=27.00 [1–e–0.247(t+0.876)] and Wt =249.66 [1-e–0.247(t+0.876)]3.248 for female, Lt=27.55 [1–e–0.232(t+0.952)] and Wt=280.02 [1–e–0.232(t+0.952)]3.252 for male, Lt=27.34 [1–e–0.238(t+0.916)] and Wt=261.55 [1–e–0.238(t+0.916)]3.249 for all individuals. Growth performance index (Ф') value was calculated as 2.250 for all individuals. Condition factor varies between 0.548-1.653 in female and 0.567-1.670 in male. It was observed that the value of the condition factor generally increased with age.


2003 ◽  
Vol 60 (5) ◽  
pp. 1086-1102 ◽  
Author(s):  
C Piñeiro ◽  
M Saínza

Abstract Difficulties in age estimation for hake (Merluccius merluccius) have hampered the assessment of stocks. Here, we describe new, agreed ageing criteria based on the interpretation of the pattern of otolith growth. Improved estimates of von Bertalanffy growth parameters, and new estimates of maturity ogive parameters and length–weight relationships for European hake from Iberian Atlantic waters are presented. The results came from a study carried out during 1996–1997 and provide the first published account of the main life history traits of Southern stock hake. von Bertalanffy growth parameters of males were L∞ = 70cm, K = 0.18 year−1, and t0=−0.97 year, and those of females were L∞ = 89cm, K = 0.13 year−1, and t0 = −1.15 year. Growth of sexes differed from age 3 onwards, with females being on average larger and heavier than males. The estimated total length (L, cm)–total weight (W, g) relationships were W=0.0132135L2.8134246 for males and W=0.0086471L2.942563 for females. Spawning took place from December to May with a peak in February. The mean length and age at first maturity were 32.8 cm at 2.5 years for males and 45 cm at 4.4 years for females. Application of new ageing criteria showed that otolith sections may be used to determine ages up to 5 years in a consistent manner. These results indicate that hake of the Southern stock grow at higher rates and mature earlier than previously considered. Summaries of hake's life history parameters from other marine regions are also presented in order to make information that belongs largely to the grey literature available.


2021 ◽  
Vol 50 (3) ◽  
pp. 269-277
Author(s):  
Salim Serkan Güçlü ◽  
Saud M. Al Jufaili ◽  
Laith A. Jawad

Abstract This work is one of the first studies on the growth of Poecilia latipinna outside its natural habitat. The objective of our study was to investigate the growth parameters of the population of P. latipinna, which is an alien species in Oman (Wadi Al-Bahayes). The population structure of P. latipinna in Wadi Al-Bahayes (Oman; 23°40′47″N; 58°11′36″E) was studied in June and August 2020, using 124 fish. In the course of this study, the number of individuals of each sex, age, weight and size composition were determined. In addition, the total length–weight relationship (LRW) was calculated, as well as the von Bertalanffy growth equation. The mean growth performance (phi prime) and the condition factor were calculated. Males accounted for 37.10% and females for 62.90% of the population. The length–weight relationship and the von Bertalanffy growth equation were W = 0.0214 × L 2.7889 R2 = 0.9212, Lt = 11.46 (1 − e −0.127 (t + 2.71)) for males and Lt = 14.51 (1 − e−0.072 (t + 3.98)) for females. The mean growth performance and the condition factor were calculated as 1.22 for males and 1.18 for females and 1.54 for all specimens. The study shows that the population of the species is characterized by a wide age range. Consequently, monitoring of this alien species is highly recommended.


2009 ◽  
Vol 67 (1) ◽  
pp. 62-70 ◽  
Author(s):  
Capucine Mellon-Duval ◽  
Hélène de Pontual ◽  
Luisa Métral ◽  
Loic Quemener

Abstract Mellon-Duval, C., de Pontual, H., Métral, L., and Quemener, L. 2010. Growth of European hake (Merluccius merluccius) in the Gulf of Lions based on conventional tagging. – ICES Journal of Marine Science, 67: 62–70. Growth of European hake was estimated from the results of a conventional tagging study in the Gulf of Lions, the first tagging experiment to have been undertaken on the species in Mediterranean waters. In all, 4277 hake 15–40 cm long were tagged and released on the inshore fishing grounds during spring 2006. The overall recapture rate was 6.5% and times-at-liberty ranged from 1 to 717 d. Growth rate in hake varied with size and sex. The estimated growth parameter (von Bertalanffy k) was estimated as double previously published values based on size frequency distribution in the area. Compared with recent growth parameters derived from the tagging experiments in the Bay of Biscay, k was estimated to be slightly lower in the Gulf of Lions. With this faster growth, hake would mature earlier than previously thought: at age 2 for both sexes, instead of at age 3 or 4 as currently accepted for the Mediterranean. Growth rate by sex decreased to a similar level once fish had attained sexual maturity.


Author(s):  
Abdul-Razak M. Mohamed ◽  
Mohanad O. Al-Jubouri

The age, growth, relative condition factor, and reproduction of Planiliza abu (Heckel, 1843) from the Al-Diwaniya River, Iraq was described in samples obtained from October 2016 to September 2017, using different fishing gears. Total length and weight were measured, scales were used for age determination, and gonads were excised from the body cavity sexed and weighed. The lengths of the species ranged from 7.0 to 20.0 cm, and the most dominant length group was 13.0 cm. The length-weight relationship was W=0.0199*L2.821 revealing a negative allometric growth (b= 2.821). The mean relative condition factor (Kn) was calculated as 1.13 for females and 0.93 for males. Four ages were recognized for the species with mean total lengths of 10.2, 14.5, 39.0, 17.2 and 19.3 cm, respectively. The von Bertalanffy growth parameters based on back-calculated lengths were L∞= 23.4 cm, K=0.38 and to= -0.27. The growth performance index (Ø) of the species is computed as 2.32. The overall sex ratio (male: female) was 1:1.70. The gonad-somatic index (GSI) values of both sexes were highest in April, 8.5 for males and 11.6 for females and the lowest values in August, 0.22 for males and 0.75 for females, indicated that the spawning period was from April to May. Some biological properties such as lengths of individuals, negative allometric growth, ages from 1 to 4 years, values of ultimate growth (L∞) and growth performance index (Ø) and overall sex ratio were among those described for the species in other waters. These results can contribute to providing information for species management in the study river.


2020 ◽  
Vol 49 (4) ◽  
pp. 383-390
Author(s):  
Ali Ilhan ◽  
Hasan M. Sarı ◽  
Irmak Kurtul

AbstractThe objective of this study was to determine growth parameters, such as age–length and length–weight relationships, as well as condition factors and sex ratio, of the Carassius gibelio (Bloch, 1782) population in Lake Marmara (western region of Turkey), which is one of the most important fishing areas. Fish were caught on a monthly basis by gillnets and trammel nets (mesh size 10–50 mm) between March 2012 and February 2013. A total of 1058 specimens (809 females and 249 males) were examined. The female–male ratio was 1:0.31. The maximum age was determined as VI and V for females and males, respectively. The total length of females and males ranged from 10.0 to 27.5 cm and from 10.2 to 24.0 cm, respectively. Their weight varied from 17.1 to 378.4 g and from 17.7 to 244.9 g, respectively. Length–weight relationship parameters were a = 0.014 and b = 3.040 for females and a = 0.015 and b = 3.039 for males. Von Bertalanffy growth parameters of the C. gibelio population were as follows: L∞ = 35.86 cm, k = 0.189 year−1, t0 = −1.238 years. Minimum and maximum condition factors were 1.56 for females in October and 1.82 in May and 1.67 for males in September and 1.94 in January.


1999 ◽  
Vol 50 (2) ◽  
pp. 103 ◽  
Author(s):  
P. L. Horn ◽  
R. J. Hurst

Age determination of gemfish by counting hyaline zones in otoliths was validated by following the progression of modes in length–frequency distributions and the progression of strong and weak year classes in age–frequency distributions. Length–frequency and otolith samples were examined from four areas (west Northland, east Northland and Bay of Plenty, Wairarapa coast, and the Stewart- Snares shelf). Age–frequency distributions and von Bertalanffy growth parameters were calculated and compared between areas. Two gemfish stocks are indicated on the basis of patterns of year class strengths, trends in commercial landings and likely spawning areas; one off the east and north of the North Island, and another off the west and south of the South Island. Estimates of natural mortality are presented for the two stocks.


Author(s):  
Naciye Erdoğan Sağlam ◽  
Yeşim Demir Sağlam ◽  
Cemil Sağlam

The population parameters of mantis shrimp (Squilla mantis Linnaeus, 1758) were studied regarding age composition, sex ratio, growth, survival and mortality rates, and the exploitation rate in the Aegean coasts of Turkey in 2013. We collected 936 specimens by shrimp gillnets along the coasts of Izmir Province from April to October 2013. The mean condition factor was K = 1.02 for both sexes, while the sex ratio was 58.7% for female and 41.3% male. Mean lengths, mean weight and length–weight relationship were calculated as TL = 12.57 ± 0.07 cm, CL = 3.02 ± 0.02 cm, W = 22.14 ± 0.37 g, W = 0.0098 × L3.02. Age determination was based on indirect ageing through length–frequency data using the Bhattacharya method. The age of the population varied from 0+ to 3+. Von Bertalanffy growth parameters were estimated as TL∞ = 19.69 cm, CL∞ = 4.74, W∞ = 79.41 g, k = 0.50 year−1 and t0 = −0.37 year. Mortality and exploitation rates derived as Z = 1.90, M = 1.16, F = 0.74 and E = 0.39, respectively.


2019 ◽  
pp. 23-31 ◽  
Author(s):  
George N. Hotos

Growth and mortality of L. aurata (Risso,1810) were estimated in the lagoon of Klisova-Messolonghi (W. Greece), based on age estimation from scale readings of a total of 1048 individuals, ranging between 10 and 59 cm in total length (TL). Age determination revealed nine age classes (0+ to 8+). Maximum age was found to be 8 years for females and 6 years for males respectively. The growth pattern of L. aurata exhibited allometry (b=3.26). The species seems to achieve 34% of its growth during the first year; thereafter the annual growth rate drops. Both sexes presented similar von Bertalanffy growth curves. The von Bertalanffy growth function for the estimated total length-at-age was found Lt = 70.78 [1 - e -0.129(t+1.345)] for the combined sexes. Otolith weight, length and width were tested and they were found to be very good predictors for age. Between the present L. aurata growth parameters and those of other Mediterranean, Caspian and Atlantic Sea for the same species, there were found significant differences in its growth parameters. The total (Z) and natural (M) mortality rate was found to be 0.54 years-1 and 0.33 years-1 respectively. The estimated exploitation rate was found to be E=0.395 which suggests that the existing fishing pressure on L. aurata is rather moderate in the investigated region.


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