Life-history traits of the striped red mullet Mullus surmuletus (Linnaeus, 1758) in the south Aegean Sea (eastern Mediterranean)

2019 ◽  
Vol 99 (06) ◽  
pp. 1417-1427 ◽  
Author(s):  
Vasiliki Kousteni ◽  
Aikaterini Anastasopoulou ◽  
Chryssi Mytilineou
Keyword(s):  
Stock Assessment ◽  
Eastern Mediterranean ◽  
Gonadosomatic Index ◽  
Aegean Sea ◽  
Growth Function ◽  
Reproductive Period ◽  
The South ◽  
Striped Mullet ◽  
Mullus Surmuletus ◽  
Marginal Increment

AbstractAlthough the red striped mullet is one of the main target fish of the Hellenic demersal fisheries, information about its biology is limited. The aim of this study was to describe the reproductive biology and growth of the species in the south Aegean Sea based on 1032 individuals sampled under the Data Collection Framework Program in 2016. According to the monthly variation of the maturity stages and the gonadosomatic index, spawning activity took place from March to July, although it appeared to occur throughout the year. Length at 50% maturity (L50) was 153.3 and 139.2 mm in females and males, respectively. Individual ages were determined by counting the annuli of otoliths macroscopically. Marginal increment analysis (MIA) combined with complementary information derived from otolith edge analysis, the assessment of the reproductive period and the length–frequency distribution modes of the population showed that annulus formation occurs between February and April. The length–weight relationship revealed a significant sex effect and was described by the parameters α = 0.0155 and b = 2.915 in females, and α = 0.0032 and b = 2.976 in males. The von Bertalanffy growth function (VBGF) parameters for sexes combined were Linf = 346.1 mm, k = 0.299 year−1 and t0 = −0.984 years. Longevity (tmax) was estimated at 11.75 years. This study provides valuable data for the stock assessment of M. surmuletus in one of the major Hellenic fishing grounds located in the south Aegean Sea.

scholarly journals Key Environmental Factors Controlling Planktonic Foraminiferal and Pteropod Community’s Response to Late Quaternary Hydroclimate Changes in the South Aegean Sea (Eastern Mediterranean)

2020 ◽  
Vol 8 (9) ◽  
pp. 709
Author(s):  
Christina Giamali ◽  
George Kontakiotis ◽  
Efterpi Koskeridou ◽  
Chryssanthi Ioakim ◽  
Assimina Antonarakou
Keyword(s):  
Environmental Factors ◽  
Environmental Changes ◽  
Late Quaternary ◽  
Eastern Mediterranean ◽  
Planktonic Foraminifera ◽  
Explanatory Power ◽  
Principal Component ◽  
Aegean Sea ◽  
Late Glacial ◽  
The South

A multidisciplinary study was conducted in order to investigate the environmental factors affecting the planktonic foraminiferal and pteropod communities of the south Aegean Sea. Aspects of the Late Quaternary paleoceanographic evolution were revealed by means of quantitative analyses of planktonic foraminiferal and pteropod assemblages (including multivariate statistical approach; principal component analysis (PCA)), the oxygen (δ18O) and carbon (δ13C) isotopic composition of planktonic foraminifera and related paleoceanographic (planktonic paleoclimatic curve (PPC), productivity (E-index), stratification (S-index), seasonality) indices, extracted by the gravity core KIM-2A derived from the submarine area between Kimolos and Sifnos islands. Focusing on the last ~21 calibrated thousands of years before present (ka BP), cold and eutrophicated conditions were identified during the Late Glacial period (21.1–15.7 ka BP) and were followed by warmer and wetter conditions during the deglaciation phase. The beginning of the Holocene was marked by a climatic amelioration and increased seasonality. The more pronounced environmental changes were identified during the deposition of the sapropel sublayers S1a (9.4–7.7 ka BP) and S1b (6.9–6.4 ka BP), with extremely warm and stratified conditions. Pteropod fauna during the sapropel deposition were recorded for the first time in the south Aegean Sea, suggesting arid conditions towards the end of S1a. Besides sea surface temperature (SST), which shows the highest explanatory power for the distribution of the analyzed fauna, water column stratification, primary productivity, and seasonality also control their communities during the Late Quaternary.

scholarly journals Fecundity of Morocco Dentex Dentex maroccanus Valenciennes, 1830 Distributed in Izmir Bay (Central Aegean Sea of Turkey)

2018 ◽  
Vol 6 (5) ◽  
pp. 624
Author(s):  
Burcu Taylan ◽  
Bahar Bayhan ◽  
Oğulcan Heral
Keyword(s):  
Gonadosomatic Index ◽  
Aegean Sea ◽  
Reproductive Period ◽  
Male Fish ◽  
Exponential Relationship ◽  
Phase Discrimination ◽  
Total Fecundity ◽  
Fish Samples ◽  
Dentex Dentex ◽  
Discrimination Method

In this study, the reproductive properties of the Dentex maroccanus species distributed in the Aegean Sea were determined. A total of 439 fish were collected during the period from December 2012 to March 2014 from the commercial fishers who seasonally hunt in the Foça-Mordoğan region (İzmir, Turkey) were examined. After the measurement of the total lengths and body and gonad weights of the fish samples in the laboratory, their sexes were identified, which revealed that 140 of the samples were male, 206 of the samples were female and 93 of the sample were undeterminated. The female:male ratio was 1.5:1. The 5-point maturity phase discrimination method developed by Holden and Raitt for maturity stages in 1974 was macroscopically examined for female and male fish specimens. A total of 16 ovaries, which were determined to be at the 3rd and 4th stages of maturity according to the method, were used to determine fecundity. The gonadosomatic index values that were calculated based on the seasons revealed that the reproductive period of the species was summer (2.87) and autumn (2.10). The first maturation length for the species was 13.4 cm. Estimates of total fecundity varied between 74252 and 201187 eggs (mean: 123263±44586). There was an exponential relationship between fecundity and total length as F = 10.643L3.111. The diameter of the mature eggs ranged from 0.49 mm to 0.67 mm (mean: 0.59±0.06 mm).

Biology of the cocktail shrimp, Trachysalambria curvirostris (Decapoda: Penaeidae) in the Yellow Sea of Korea

2004 ◽  
Vol 84 (2) ◽  
pp. 351-357 ◽  
Author(s):  
H.K. Cha ◽  
C.W. Oh ◽  
J.H. Choi
Keyword(s):  
Carapace Length ◽  
Growth Parameters ◽  
Gonadosomatic Index ◽  
Growth Curves ◽  
Growth Function ◽  
Mature Female ◽  
The Yellow Sea ◽  
The South ◽  
Frequency Distributions ◽  
North West

Trachysalambria curvirostris occurs widely along the south and west coasts of Korea with a range extending from Kanghwado in the north-west, down to Sarangdo in the south-east. With seasonal warming of the waters starting in April, the shrimps begin to migrate from deep waters to the coastal area. Zoea and mysis larvae occurred from June to August. Sex ratio showed seasonal variations, with a mean value of 56·7% for the females. The species produces one cohort a year, with the ovaries ripening from June to July. Insemination appeared to take place from June to August, as more than half of the females sampled in the study over 15–16 mm carapace length were inseminated. Mean gonadosomatic index (GSI) reached a maximum between June and July. The smallest mature female found was 15 mm carapace length (CL). Size at 50% sexual maturity (CL50), determined from both mature females and inseminated females, was 15·37 mm and 16·49 mm CL, respectively. Fecundity was directly proportional to the size of the female, with clutch sizes varying from 16,380 eggs in the smallest female to 114,621 eggs in the largest, and the eggs ranged from 230 μm to 340 μm in diameter. The life span of females appeared to be 14–15 months according to size frequency distributions, while that of the male was 13–14 months. Population growth was estimated by the modified von Bertalanffy growth function incorporating seasonal variation in growth. Based on the growth parameters (K=2·00 y−1 and L∞=24·64 mm CL for females, and K=2·00 y−1 and L∞=19·00 mm CL for males) growth curves showed that females grew faster and reached a larger size at age than males. This result is supported by differences in growth performance indices (ϕ′).

Bathypolypus sponsalis (Cephalopoda: Octopoda) from the central western Mediterranean Sea

2009 ◽  
Vol 91 (2) ◽  
pp. 549-553 ◽  
Author(s):  
D. Cuccu ◽  
M. Mereu ◽  
M.C. Follesa ◽  
A.M. Deiana ◽  
A. Cau
Keyword(s):  
Mediterranean Sea ◽  
Depth Distribution ◽  
Size Structure ◽  
Eastern Mediterranean ◽  
Gonadosomatic Index ◽  
First Record ◽  
Western Mediterranean ◽  
Reproductive Period ◽  
Tyrrhenian Sea ◽  
Western Mediterranean Sea

A sample of 360 Bathypolypus sponsalis from the central western Mediterranean Sea (the Sardinian Channel and the Tyrrhenian Sea) was analysed in order to describe size, depth distribution and reproductive data. The first record of the species in the Tyrrhenian Sea and of a spent female are reported in this paper. The size-structure of the sample was in between values of documented data from the western and eastern Mediterranean basins and the minimum mature sizes in both sexes and spermatophore length were similar to previous data from the eastern Mediterranean Sea. Low values of gonadosomatic index and fecundity, the asynchronous ovulation, in addition to an extended reproductive period, have been associated with an intermittent spawning strategy.

scholarly journals Reproductive biology of Plesionika narval in the SE Aegean Sea (Eastern Mediterranean)

2017 ◽  
pp. 454 ◽  
Author(s):  
AIKATERINI ANASTASOPOULOU ◽  
PANAGIOTA MAKANTASI ◽  
KOSTAS KAPIRIS ◽  
CHRIS J. SMITH ◽  
CHRISTOS MARAVELIAS ◽  
...  
Keyword(s):  
Reproductive Biology ◽  
Carapace Length ◽  
Gonadosomatic Index ◽  
Aegean Sea ◽  
Reproductive Period ◽  
Small Scale ◽  
Female Size ◽  
Depth Range ◽  
Depth Zone ◽  
Widespread Species

Plesionika narval is a widespread species of the Pandalidae family, of particular high economic importance for small-scale shrimp trap fisheries in the Dodecanese Islands (SE Aegean Sea). Understanding its biology and reproduction are crucial for stock management. Reproductive biology aspects were studied through data collected during monthly experimental surveys with baited shrimps traps from November 2014 to October 2015 at a depth range of 10 - 150m. A total of 3436 individuals within the size range of 6.46 to 20.20 mm carapace length (CL) was analyzed. Overall, mean female size was significantly higher than mean male size, while the mean size of ovigerous females was higher than that of non-ovigerous females. Mean carapace length of ovigerous and non-ovigerous females was significantly correlated to depth. Ovigerous females were observed throughout the study period; however, monthly proportions revealed April to October as the main reproductive period of the species in the area. The sex ratio showed a clear predominance of females in the shallow depth zone (10-25 m) and was found to be affected by sampling area and depth zone. Immature females were found from November to March. Mature females were found all year round, exhibiting higher percentages in March, June, July and September, coinciding with the main reproductive period. P. narval seemed to spawn more than one time within the annual reproductive cycle. Gonadosomatic index obtained its highest mean values in May, June and September, thus revealing the main reproductive period. Size at first maturity for females was estimated at CL50=11.7 mm.

scholarly journals Applying a two-stage Bayesian dynamic model to a short lived species, the anchovy in the Aegean Sea (Eastern Mediterranean). Comparison with an Integrated Catch at Age stock assessment model.

2014 ◽  
Vol 15 (2) ◽  
pp. 350 ◽  
Author(s):  
M. GIANNOULAKI ◽  
L. IBAIBARRIAGA ◽  
K. ANTONAKAKIS ◽  
A. URIARTE ◽  
A. MACHIAS ◽  
...  
Keyword(s):  
Egg Production ◽  
Missing Values ◽  
Stock Assessment ◽  
Eastern Mediterranean ◽  
Aegean Sea ◽  
Production Method ◽  
Assessment Model ◽  
Two Stage ◽  
Commercial Catch ◽  
The North

Two different stock assessment models were applied to the North Aegean Sea anchovy stock (Eastern Mediterranean Sea): an Integrated Catch at age Analysis and a Bayesian two-stage biomass based model. Commercial catch data over the period 2000-2008 as well as acoustics and Daily Egg Production Method estimates over the period 2003-2008 were used. Both models results were consistent, indicating that anchovy stock is exploited sustainably in relation to an exploitation rate reference point. Further, the stock biomass appears stable or increasing. However, the limitations in age-composition data, potential problems related to misinterpretation of age readings along with the existence of missing values in the survey data seem to favour the two-stage biomass method, which is based on a simplified age structure.  

Population structure of the protected fan musselPinna nobilisin the south Aegean Sea (eastern Mediterranean)

2014 ◽  
Vol 94 (4) ◽  
pp. 787-796 ◽  
Author(s):  
Dimitris Vafidis ◽  
Chryssanthi Antoniadou ◽  
Eleni Voultsiadou ◽  
Chariton Chintiroglou
Keyword(s):  
Size Structure ◽  
Habitat Degradation ◽  
Eastern Mediterranean ◽  
Aegean Sea ◽  
Current Status ◽  
Small Scale ◽  
The South ◽  
Depth Zone ◽  
Size Frequency Distribution ◽  
Temporal Sampling

Pinna nobilisis an endemic Mediterranean species of high economic and cultural importance. Nowadays, it is under strict protection as a dramatic decline in its populations has been recognized, assigned to the combined effect of fisheries and habitat degradation. This study attempts to evaluate, by non-destructive sampling, the current status ofP. nobilispopulations in the south Aegean Sea (Dodecanese island complex), where they have been affected for centuries by practically uncontrolled harvesting. Population density and total length of individuals was estimated by diving along strip transects at six islands. Two stations were randomly selected per island, and two depth zones were surveyed per station. Additionally, temporal sampling was carried out at Astypalaia Island from March 2004 to June 2006, to assess relevant trends in density of individuals and size structure of the population. In total 1372P. nobilisindividuals were measuredin situto estimate maximum shell length. The studied populations showed increased density in the shallower depth zone and sheltered sites; small-scale environmental regimes are proposed as shaping factors ofP. nobilisdistribution. Increased density was also detected during the cold period of the year, probably related to recruitment success. In the lower depth zone theP. nobilispopulation consisted of larger individuals. A significant decrease in size was detected temporally as mean length was smaller in December 2004; in the same month the presence of small-sized juveniles was depicted in a left-shift in size–frequency distribution. These observations are probably related to the reproductive biology of the species.

The reproductive cycle of a deep-sea eel, Nettastoma melanurum (Nettastomatidae: Anguilliformes) from the south-eastern Sardinian Sea (central-western Mediterranean)

2012 ◽  
Vol 93 (4) ◽  
pp. 1105-1115 ◽  
Author(s):  
Cristina Porcu ◽  
Maria Cristina Follesa ◽  
Alice Gastoni ◽  
Antonello Mulas ◽  
Claudia Pedoni ◽  
...  
Keyword(s):  
Reproductive Cycle ◽  
Deep Sea ◽  
Gonadosomatic Index ◽  
Western Mediterranean ◽  
Reproductive Period ◽  
Sexually Dimorphic ◽  
The South ◽  
South Eastern ◽  
Monthly Changes ◽  
First Maturity

The reproductive cycle of the deep-sea eel Nettastoma melanurum was described based on 397 specimens (171 males and 226 females). Experimental trawl surveys between depths of 772 and 1598 m and commercial hauls (580–600 m) on compact mud bottoms off the south-eastern Sardinian waters (central-western Mediterranean) were carried out. The Sardinian catches did not indicate any particular trend of size-range in relation to depth in both sexes and seem to be sexually dimorphic with females growing almost 9 cm longer than males at maximum lengths. It was a dioeceous and an oviparous deep-sea species. For females and males, six stages of oocyte development, characterizing the different stages of maturity, were identified. Histological examination demonstrated that ovaries of N. melanurum showed a ‘group-synchronous’ pattern, highlighting a type of monocyclic ovary. The species showed a size at first maturity of 53.5 cm and 50.5 cm total length in females and males respectively. The reproductive period appeared to be unique and well defined in both sexes. Their monthly changes of gonadosomatic index and maturation phases of ovaries and testis showed that the species was in a resting period from March to July. Vitellogenesis and spawning began in September and ended in January. Nettastoma melanurum seemed to be a fecund species (8132–18755 eggs).

scholarly journals Distribution and transfer of trace metals in the Aegean Seawater (Eastern Mediterranean Basin)

2000 ◽  
Vol 1 (2) ◽  
pp. 5 ◽  
Author(s):  
F. VOUTSINOU-TALIADOURI ◽  
C. ZERI ◽  
A. MORIKI
Keyword(s):  
Trace Metals ◽  
Trace Metal ◽  
Eastern Mediterranean ◽  
Aegean Sea ◽  
The Black Sea ◽  
The South ◽  
Metal Concentrations ◽  
The North ◽  
North Aegean ◽  
North Aegean Sea

Recent measurements of dissolved Cd, Cu, Ni and Mn in 324 water samples of the Aegean Sea fill the gap of missing knowledge in this part of the Eastern Mediterranean and try to identify their main input sources and spreading pathways. The analyses indicate that trace metal concentrations in the North and South Aegean Sea are generally in good agreement with those reported for the Western Mediterranean Sea. In the North Aegean Sea the trace metal distribution patterns differentiate mainly according to the existing water masses. Hence, a strong influence of the Black Sea Water, enriched in trace metals, is clearly recorded for Mn. Concentrations of this metal are one order of magnitude higher in the surface layer than those of the deeper waters. This feature is followed to a lesser degree also by Cd, Cu and Ni. Trace metal concentrations in the South Aegean Sea reveal almost constant values throughout the watercolumn similar to those observed in the North Aegean Sea below the depth of 100 m. Manganese values in the South Aegean Sea are considerably lower comparing with the North Aegean ones, showing relatively enhanced surface values which decrease with depth.

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