scholarly journals Age and growth of four-spotted megrim (Lepidorhombus boscii Risso, 1810) from Saros Bay (Northern Aegean Sea, Turkey)

2013 ◽  
Vol 14 (1) ◽  
pp. 36 ◽  
Author(s):  
O. CENGIZ ◽  
U. OZEKINCI ◽  
A. ISMEN ◽  
A. OZTEKIN
Keyword(s):  
Sex Ratio ◽  
Growth Performance ◽  
Performance Index ◽  
Growth Parameters ◽  
Aegean Sea ◽  
Bottom Trawl ◽  
Age And Growth ◽  
Trawl Fishery ◽  
Northern Aegean Sea

In this study, the growth parameters of the four-spotted megrim, (Lepidorhombus boscii Risso, 1810), were studied in Saros Bay, which had been closed to bottom trawl fishery since 2000. The sex ratio of females to males was 1:0.42. Length-weight relationships were W=0.0032L3.31 and W=0.0069L3.04 for females and males, respectively. Growth parameters of the populations were L∞=49.8 cm, k=0.09 year-1, t0=-2.15 year for females; L∞=39.1 cm, k=0.11 year-1, t0=-2.59 year for males. The growth performance index (Φ’) was found to be 2.35 and 2.23 for females and males, respectively.

scholarly journals Age, Growth, Condition Factor and Reproduction of Planiliza abu (Mugiliformes: Mugilidae) in the Al-Diwaniya River, Middle of Iraq

2021 ◽  
pp. 20-29
Author(s):  
Abdul-Razak M. Mohamed ◽  
Mohanad O. Al-Jubouri
Keyword(s):  
Sex Ratio ◽  
Growth Performance ◽  
Performance Index ◽  
Condition Factor ◽  
Age Determination ◽  
The Body ◽  
Allometric Growth ◽  
Spawning Period ◽  
Relative Condition Factor ◽  
Gonad Somatic Index

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.

A study on some population parameters of mantis shrimp (Squilla mantis L., 1758) in Izmir Bay (Aegean Sea)

2017 ◽  
Vol 98 (4) ◽  
pp. 721-726 ◽  
Author(s):  
Naciye Erdoğan Sağlam ◽  
Yeşim Demir Sağlam ◽  
Cemil Sağlam
Keyword(s):  
Sex Ratio ◽  
Condition Factor ◽  
Growth Parameters ◽  
Age Determination ◽  
Aegean Sea ◽  
Population Parameters ◽  
Age Composition ◽  
Mantis Shrimp ◽  
The Mean ◽  
Length Frequency Data

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.

scholarly journals Assessment of goatfish fisheries in Turkey based on the microdata set of official landing statistics

2021 ◽  
Vol 38 (3) ◽  
pp. 303-309
Author(s):  
Nuray Çelik Mavruk ◽  
Sinan Mavruk ◽  
Dursun Avşar
Keyword(s):  
Mediterranean Sea ◽  
Black Sea ◽  
Large Scale ◽  
Aegean Sea ◽  
Bottom Trawl ◽  
The Black Sea ◽  
Marmara Sea ◽  
Trawl Fishery ◽  
Red Mullet ◽  
The Mediterranean

Although goatfishes (Mullidae Rafinesque, 1815) are among the most important commercial fishes in Turkey, no research has been found investigating the characteristics and spatial patterns of goatfish fishery. Here, we assessed the goatfish fishery of Turkey based on the microdata set of Turkish National Fishery Statistics gathered by Turkish Statistical Institute (TÜİK) between 2014 and 2017. In this context, we investigated the variation of total goatfish catch by cities. In addition, we compared the contribution of small (boat <10m) and large scale (boat >10m) fishers as well as different fishing techniques to the total goatfish catch in Turkey. Finally, an evaluation was made on the discard rates recorded in the official landing statistics. The results showed that higher red mullet (Mullus barbatus Linnaeus, 1758) catch was reported in the eastern Mediterranean, whereas surmullet (Mullus surmuletus Linnaeus, 1758) catch was significantly higher in the western Black Sea. On the other hand, fishery-independent investigations revealed that the Turkish fishery fleet mostly catches red mullet throughout the coasts of Turkey. Therefore, the separate records of red mullet and surmullet in the landing statistics likely represent the local names of red mullet rather than two different species. Large scale fishers were the main source of fishery pressure in the Mediterranean Sea, the Aegean Sea and the Black Sea. However, the majority of the catch was landed by small scale fishers in the Marmara Sea. The bottom trawl fishery landed 88, 92 and 87% of total goatfish catch in the Black Sea, the Aegean Sea and the Mediterranean Sea, respectively. Purse seiners provided the largest part of total goatfish catch (40%) in the Marmara Sea, where the bottom trawl fishery is prohibited. The overall average for the discard rate was found to be 0.47%. There were no statistically significant differences among the discard rates of two species, marine regions or fishing methods.

scholarly journals Age and Growth of Black-Bellied Anglerfish Lophius budegassa (Spinola, 1807) from the Central Aegean Sea, Turkey

2020 ◽  
Vol 78 (1) ◽  
pp. 45-51
Author(s):  
Ahmet Mert Şenbahar ◽  
Okan Özaydin
Keyword(s):  
Growth Parameters ◽  
Growth Ring ◽  
Age Groups ◽  
Aegean Sea ◽  
Age And Growth ◽  
Von Bertalanffy ◽  
Dorsal Fin ◽  
Trawl Fishing ◽  
First Ray

AbstractA total of 558 specimens of black-bellied anglerfish Lophius budegassa (Spinola, 1807) were collected by the vessels engaged in commercial trawl fishing in the Central Aegean Sea between September 2017 and August 2018 in order to determine age and growth. Ageing was based on growth ring counts of transverse sections of the illicium (first ray of the dorsal fin). By reading the illicium, individuals were found within II-XI age groups. Total lengths and weights ranged between 12.0 – 65.0 cm and 24.5 – 4682.0 g, respectively. Von Bertalanffy growth parameters were estimated for males, females and combined sexes of L. budegassa. The results are compared with previous studies.

Age and growth of adult gilthead seabream (Sparus aurata L.) in the Aegean Sea

2010 ◽  
Vol 91 (6) ◽  
pp. 1255-1259 ◽  
Author(s):  
Okan Akyol ◽  
Kutsal Gamsiz
Keyword(s):  
Sparus Aurata ◽  
Growth Parameters ◽  
Age Groups ◽  
Fork Length ◽  
Aegean Sea ◽  
Age And Growth ◽  
Gilthead Seabream ◽  
Total N ◽  
Eastern Aegean ◽  
Wet Weight

Age and growth of adult gilthead seabream, Sparus aurata were determined from 332 specimens (total N = 476), collected from purse-seiners, in the south-eastern Aegean Sea from November 2006 to January 2007. The fork length and body wet weight ranged from 26.5 to 51.5 cm (mean: 36.6 ± 0.18) and from 375 to 2600 g (mean: 1009.2 ± 14.16), respectively. Age groups were varied between 2 and 7. Growth parameters were estimated as L∞ = 64.97 ± 12.93 cm, K = 0.14 ± 0.07 year−1, t0 = −2.47 ± 1.09 year−1, and index of phi-prime was Φ′ = 2.772 ± 0.51. The length–weight relationship equation of all fish was calculated as W = 0.0515 × L2.737 (r2 = 0.95). The mean condition factor was estimated as 2.058. Mortalities (M, F and Z) and exploitation rate (E) of gilthead seabream from the Aegean Sea were 0.34 year−1, 0.77 year−1, 1.11 year−1and 0.69 year−1, respectively. The result of E indicated that the population was overexploited.

Discards in bottom trawl fishery in the Aegean Sea (Izmir Bay, Turkey)

2013 ◽  
Vol 29 (6) ◽  
pp. 1269-1274 ◽  
Author(s):  
R. Gurbet ◽  
O. Akyol ◽  
E. Yalçın ◽  
O. Özaydın
Keyword(s):  
Aegean Sea ◽  
Bottom Trawl ◽  
Izmir Bay ◽  
Trawl Fishery

scholarly journals The Growth Parameters and Mortalities of Five Species of Synodonits in the Lower River Benue at Makurdi

2021 ◽  
Vol 3 (3) ◽  
Author(s):  
Akombo, Pauline Mbakaan ◽  
Atile, John Iornyiman ◽  
Shima, Judith Nguvan
Keyword(s):  
Growth Rate ◽  
Growth Performance ◽  
Performance Index ◽  
Growth Parameters ◽  
Total Mortality ◽  
Natural Mortality ◽  
Fishing Mortality

The growth parameters and mortalities of five species of Synodontis in the lower river Benue at Makurdi, Benue State were studied from January,2016 to December, 2018. The asymptotic length (L∞) calculated for the five species ranged from 18.80cm in S.clarias females to 37.04cm in S.membranaceus females. The t0 values were all negative in the combined sexes of S.clarias, S.omias, S.gambiensis and S.membranaceus. In both combined sexes of S.membranaceus and S.schall, the t0 values were positive. The growth rate (K) was low in S.clarias and S.omias (0.301- 0.497, 0.171 - 0.310) respectively and higher in S.membranaceus (0.310 - 0.640), S.schall females (0.430 - 0.580); S.schall males (0.573),S.gambiensis (0.500 - 0.571). Growth performance index (Ø’) was 2.212 in S.gambiensis and 2.946 in S.schall combined. Natural Mortality (M) ranged from 0.5422 in S.omias females to 1.3340 in S.membranaceus males. Fishing Mortality (F) was 0.8214 in S.omias combined and 3.0934 in S.membranaceus females. Total mortality (Z) ranged from 1.52 in S.omias combined to 4.078 in S.membranaceus combined. Mean Exploitation (E) ratios was 0.61 in S.clarias, 0.64 in S.omias, 0.53 in S.gambiences, 0.70 in S.membranaceus, and 0.66 in S.schall. The rate at which these species survived in the River was low (from 0.147, in S.omias combined, to 1.482 in S.membranaceus combined).

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