scholarly journals Population dynamics of the Mediterranean green crab Carcinus aestuarii Nardo, 1847 (Crustacea: Portunidae) in the Gediz Delta (İzmir Bay, Eastern Aegean Sea)

2020 ◽  
Vol 61 (1) ◽  
pp. 39-56
Author(s):  
Eyüp Mümtaz Tiraşin ◽  
Alp Salman ◽  
Meryem Akalin ◽  
Okan Özaydin

A total of 6265 Mediterranean green crabs Carcinus aestuarii were sampled from the Gediz Delta in the eastern Aegean Sea (Turkey) during 24 sampling surveys with a 15-day interval from November 2014 to October 2015. The overall ratio of males to females was 1.8:1. Males were predominant in all sampling surveys, except in September 2015. The ranges of total weight (W) and carapace width (CW) for all crabs were 0.19–45.74 g and 8–53 mm. Male crabs were, on average, larger and heavier than females. The W–CW relationships were W=0.0004×CW2.88 for females, and W=0.0003×CW2.96 for males. The estimated von Bertalanffy growth parameters for females were: CW∞=49 mm, K=0.82 year-1 and t0=-0.9 year, and for males CW∞=54 mm, K=0.92 year-1 and t0=-0.96 year. The total mortality rates were 2.25 and 2.27 year-1 for females and males, respectively. The breeding season spans from mid fall to early spring peaking in winter. The recruitment of juveniles to the lagoon happens predominantly in summer. The median size at first maturity was 30.6 mm for females and 41.5 mm for males. The average potential fecundity estimate was 63565±36519 oocytes per female crab while the average realized fecundity was 42810±33310 eggs.

2020 ◽  
Vol 49 (1) ◽  
pp. 13-22 ◽  
Author(s):  
Ismail Burak Daban ◽  
Ali Ismen ◽  
Mukadder Arslan Ihsanoglu ◽  
Koray Cabbar

AbstractThis study determines the length distribution, length– weight relationship, age, growth parameters, mortality rate, sex ratios, length at first maturity and reproduction of saddled seabream (Oblada melanura) collected monthly by fishermen around the Northern Aegean Sea between November 2017 and October 2018. The length–weight relationship was calculated as W=0.0091×L3.11 (R2=0.95) and positive allometric growth was found. The condition factor and GSI varied between 0.81–1.58 and 0.01–9.61, respectively. The spawning season extended from May to July and peaked in June. Total lengths at 50% maturity were 18.97 cm for males and 18.83 cm for females. Parameters of the von Bertalanffy growth equation were: L∞ =29.91 cm, K =0.27 per year, t0 =−0.82 year and age varied between 1 and 8. The instantaneous rates of total mortality (Z) and natural mortality (M) were 1.36 and 0.58 per year, respectively. Rates for fishing mortality F and exploitation E were 0.78 and 0.57 per year, respectively. The mean absolute fecundity (F) was 117 075±23 243 oocytes, ranging from 19130 to 470 132.


Crustaceana ◽  
2005 ◽  
Vol 78 (10) ◽  
pp. 1265-1267 ◽  
Author(s):  
A. Suat Ateş ◽  
Ali İşmen ◽  
Uğur Özekinci ◽  
C. Çiğdem Erdemir Yiğin

2017 ◽  
Vol 4 (2) ◽  
pp. 139-156
Author(s):  
Engin Meriç ◽  
Niyazi Avşar ◽  
M. Baki Yokeş ◽  
Fuat Şaroğlu ◽  
Erdoğan Ölmez ◽  
...  

2021 ◽  
Author(s):  
Aybige Akinci ◽  
Daniele Cheloni ◽  
AHMET ANIL DINDAR

Abstract On 30 October 2020 a MW 7.0 earthquake occurred in the eastern Aegean Sea, between the Greek island of Samos and Turkey’s Aegean coast, causing considerable seismic damage and deaths, especially in the Turkish city of Izmir, approximately 70 km from the epicenter. In this study, we provide a detailed description of the Samos earthquake, starting from the fault rupture to the ground motion characteristics. We first use Interferometric Synthetic Aperture Radar (InSAR) and Global Positioning System (GPS) data to constrain the source mechanisms. Then, we utilize this information to analyze the ground motion characteristics of the mainshock in terms of peak ground acceleration (PGA), peak ground velocity (PGV), and spectral pseudo-accelerations. Modelling of geodetic data shows that the Samos earthquake ruptured a NNE-dipping normal fault located offshore north of Samos, with up to 2.5-3 m of slip and an estimated geodetic moment of 3.3 ⨯ 1019 Nm (MW 7.0). Although low PGA were induced by the earthquake, the ground shaking was strongly amplified in Izmir throughout the alluvial sediments. Structural damage observed in Izmir reveals the potential of seismic risk due to the local site effects. To better understand the earthquake characteristics, we generated and compared stochastic strong ground motions with the observed ground motion parameters as well as the ground motion prediction equations (GMPEs), exploring also the efficacy of the region-specific parameters which may be improved to better predict the expected ground shaking from future large earthquakes in the region.


2018 ◽  
Vol 38 (3) ◽  
pp. 211-225 ◽  
Author(s):  
Neslihan Ocakoğlu ◽  
Paraskevi Nomikou ◽  
Yeliz İşcan ◽  
Maria Filomena Loreto ◽  
Danai Lampridou

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