scholarly journals Effect of twine thickness on selectivity of gillnets for bogue, Boops boops,in Turkish waters

2011 ◽  
Vol 12 (2) ◽  
pp. 358 ◽  
Author(s):  
A. AYAZ ◽  
U. ALTINAGAC ◽  
U. OZEKINCI ◽  
O. OZEN ◽  
A. ALTIN ◽  
...  
Keyword(s):  
Mesh Size ◽  
Aegean Sea ◽  
The Mean ◽  
Northern Aegean Sea ◽  
Boops Boops

To investigate the effect of twine thickness on the selectivity of multifilament gillnet targeting bogue,Boops boops L., four different stations were sampled between March and November 2008 in the northern Aegean Sea. Gillnets with 22, 23, and 25 mm nominal mesh size (bar length) each having two different twine thicknesses (approximately 0.45 mm and 0.54 mm ∅) were applied for this purpose. The deviances from the SELECT method revealed that lognormal models provided the best fits for both of the twine thicknesses. Results from the two-way ANOVA analyses revealed that the mean total lengths increased with the mesh size (F = 87.36; df = 2; P < 0.0001) and decreased with the twine thickness (F = 46.12; df = 1; P < 0.0001). The 22 mm mesh size net (0.45 mm ∅) captured significantly larger fish than the 23 mm mesh size net (0.54 mm ∅) probably due to the higher elasticity and flexibility of the thinner twine. Thus, fisheries managers should take into consideration the twine thickness while advising mesh size regulations in gillnet fisheries.

Genetic studies in four populations of the Northern Aegean Sea, Greece

1989 ◽  
Vol 78 (1) ◽  
pp. 89-106
Author(s):  
R. Schliwa ◽  
Angela Dannewitz ◽  
K. Gilbert ◽  
H. Walter
Keyword(s):  
Aegean Sea ◽  
Genetic Studies ◽  
Northern Aegean Sea

Abundance and population structure of the blue crab Callinectes sapidus (Decapoda, Portunidae) in Thermaikos Gulf (Methoni Bay), northern Aegean Sea

Crustaceana ◽  
2018 ◽  
Vol 91 (6) ◽  
pp. 641-657 ◽  
Author(s):  
Kosmas Kevrekidis ◽  
Chryssanthi Antoniadou
Keyword(s):  
Population Structure ◽  
Blue Crab ◽  
Callinectes Sapidus ◽  
Carapace Width ◽  
Seawater Temperature ◽  
Aegean Sea ◽  
Cold Season ◽  
Mean Size ◽  
Northern Aegean Sea ◽  
Fyke Nets

Abstract The blue crab Callinectes sapidus is an alien decapod established in the Mediterranean Sea. Since 2007, increased abundance has been reported from the northern Aegean Sea sustaining local scale fishery. The present work aims to assess the abundance and population structure of C. sapidus in Thermaikos Gulf using fyke nets. Population abundance, estimated as CPUE, exhibited strong temporal variability with decreased values in the cold season; this pattern was correlated with seawater temperature. Females exhibited also spatial differences with increased abundance close to the Aliakmon estuary. In total, 543 individuals were measured for carapace width. Males prevailed in the population; however, mean size was similar between sexes. Larger individuals were caught from deeper waters and the estuarine areas, whereas mean size decreased temporally. The fyke nets used proved to be size-selective, thus preventing fisheries mortality for juveniles. However, recurrent monitoring is necessary for a sustainable management of blue crab fisheries in the gulf.

scholarly journals Temporal variations of the fractal properties of seismicity in the western part of the north Anatolian fault zone: possible artifacts due to improvements in station coverage

1995 ◽  
Vol 2 (3/4) ◽  
pp. 147-157 ◽  
Author(s):  
A. O. Öncel ◽  
Ö. Alptekin ◽  
I. Main
Keyword(s):  
Fault Zone ◽  
Statistical Significance ◽  
Rock Fracture ◽  
Aegean Sea ◽  
B Value ◽  
Temporal Variations ◽  
North Anatolian Fault ◽  
North Anatolian Fault Zone ◽  
The North ◽  
Northern Aegean Sea

Abstract. Seismically-active fault zones are complex natural systems exhibiting scale-invariant or fractal correlation between earthquakes in space and time, and a power-law scaling of fault length or earthquake source dimension consistent with the exponent b of the Gutenberg-Richter frequency-magnitude relation. The fractal dimension of seismicity is a measure of the degree of both the heterogeneity of the process (whether fixed or self-generated) and the clustering of seismic activity. Temporal variations of the b-value and the two-point fractal (correlation) dimension Dc have been related to the preparation process for natural earthquakes and rock fracture in the laboratory These statistical scaling properties of seismicity may therefore have the potential at least to be sensitive short- term predictors of major earthquakes. The North Anatolian Fault Zone (NAFZ) is a seismicallyactive dextral strike slip fault zone which forms the northern boundary of the westward moving Anatolian plate. It is splayed into three branches at about 31oE and continues westward toward the northern Aegean sea. In this study, we investigate the temporal variation of Dc and the Gutenberg-Richter b-value for seismicity in the western part of the NAFZ (including the northern Aegean sea) for earthquakes of Ms > 4.5 occurring in the period between 1900 and 1992. b ranges from 0.6-1.6 and Dc from 0.6 to 1.4. The b-value is found to be weakly negatively correlated with Dc (r=-0.56). However the (log of) event rate N is positively correlated with b, with a similar degree of statistical significance (r=0.42), and negatively correlated with Dc (r=-0.48). Since N increases dramatically with improved station coverage since 1970, the observed negative correlation between b and Dc is therefore more likely to be due to this effect than any underlying physical process in this case. We present this as an example of how man-made artefacts of recording can have similar statistical effects to underlying processes.

scholarly journals Hemiasterella aristoteliana n. sp. (Porifera, Hadromerida) from the Aegean Sea with a discussion on the family Hemiasterellidae

1991 ◽  
Vol 61 (1) ◽  
pp. 43-49 ◽  
Author(s):  
Eleni Voultsiadou-Koukoura ◽  
R.W.M. van Soest
Keyword(s):  
New Species ◽  
Mediterranean Sea ◽  
Aegean Sea ◽  
Shallow Waters ◽  
The Family ◽  
The Status ◽  
Northern Aegean Sea ◽  
The Mediterranean ◽  
First Time

A representative of the genus Hemiasterella Carter, 1879 was found for the first time in the Mediterranean Sea during sampling in the shallow waters of the northern Aegean Sea. The new species, H. aristoteliana, is compared with Atlantic Hemiasterella elongata Topsent, 1928. The status of the family Hemiasterellidae is discussed.

scholarly journals Laparoscopic Ventral Hernia Repair Combined with Sleeve Gastrectomy in Morbidly Obese Patients: Early Outcomes

2019 ◽  
Vol 05 (03) ◽  
pp. e87-e91 ◽  
Author(s):  
Ahmed M.S.M. Marzouk ◽  
Heba O.E. Ali
Keyword(s):  
Sleeve Gastrectomy ◽  
Hernia Repair ◽  
Ventral Hernia ◽  
Ventral Hernia Repair ◽  
Mesh Size ◽  
Laparoscopic Ventral Hernia Repair ◽  
Abdominal Pressure ◽  
Morbidly Obese ◽  
Obese Patients ◽  
The Mean

Background Morbid obesity is a serious chronic condition with, among other symptoms, increased intra-abdominal pressure and subsequent abdominal wall hernias. The optimal management of these manifestations is still controversial. The objective of this study was to assess the early postoperative outcomes of a surgical approach combining laparoscopic ventral hernia repair (LVHR) with sleeve gastrectomy in morbidly obese patients. Methods In this retrospective study, we reviewed the files of patients who are obese with a primary ventral hernia of less than 10 cm in diameter who received simultaneous laparoscopic sleeve gastrectomy and LVHR at our institution between February 2016 and July 2018. LVHR was performed using an intraperitoneal only mesh. The individual mesh size was chosen based on the number and size of the defects. Clinical and radiological follow-ups were performed between 9 and 15 months. Results A total of 15 patients were included. Five of them were males. The mean body mass index was 45.2 kg/m2 (range: 38.7–56.2 kg/m2). The mean hernia defect size was 2.6 cm (range: 1.3–4.2 cm). Mesh size was 10 × 15 cm in five, 20 × 15 cm in seven, and 25 cm× 20 cm in three patients. All patients were discharged without complications on the second postoperative day. Mean follow-up was at 12 months. One patient presented with hernia recurrence 14 months after surgery and four patients presented with self-limited seroma. Conclusion Despite ambiguous guidelines and ongoing debate regarding simultaneous bariatric surgery and ventral hernia repair, the short-term outcomes of this approach appeared promising, provided that patients are carefully selected and receive an individually tailored approach.

Age, Growth and Reproductive Biology of the Common Two-Banded Seabream (Diplodus vulgaris Geoffroy Saint-Hilaire, 1817) from the Northern Aegean Sea, Turkey

2019 ◽  
Vol 35 (2) ◽  
pp. 679-688 ◽  
Author(s):  
Ali Ismen ◽  
Ismail Burak Daban ◽  
Mukadder Arslan Ihsanoglu ◽  
Cahide Cigdem Yıgın ◽  
Koray Cabbar ◽  
...  
Keyword(s):  
Reproductive Biology ◽  
Aegean Sea ◽  
The Common ◽  
Northern Aegean Sea
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