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 Reproductive biology of Penaeus kerathurus (Forskål, 1775) (Decapoda: Penaeidae) in the Sea of Marmara, Turkey

2021 ◽  
Vol 50 (1) ◽  
pp. 33-37
Author(s):  
Mukadder Arslan Ihsanoglu ◽  
Ismail Burak Daban ◽  
Ali Işmen ◽  
Koray Cabbar ◽  
Cahide Çiğdem Yığin
Keyword(s):  
Reproductive Biology ◽  
Sexual Maturity ◽  
Carapace Length ◽  
Gonadosomatic Index ◽  
Mediterranean Ecosystem ◽  
Sea Of Marmara ◽  
Important Species ◽  
Spawning Period ◽  
Male Ratio ◽  
First Reproduction

Abstract One of the economically important species is Penaeus kerathurus (Forskål, 1755), which is widespread in the Mediterranean ecosystem. This paper presents results of research on reproductive biology of Penaeus kerathurus in the Sea of Marmara. A total of 1404 specimens were dissected to determine the maturity stages, reproduction time, and length at first reproduction. The female-to-male ratio was 1:0.9. A high percentage of mature females was determined in April, May and July. Moreover, the value of the gonadosomatic index (GSI) decreased after July. The spawning period was observed between April and July, and its intensity increased in July. The carapace length at first sexual maturity was determined to be 39 mm.

scholarly journals Reproductive strategy of common dentex Dentex dentex: management implications

2016 ◽  
Vol 17 (2) ◽  
pp. 552 ◽  
Author(s):  
A. GRAU ◽  
F. SABORIDO-REY ◽  
E. PASTOR ◽  
M. PALMER ◽  
E. MASSUTÍ-PASCUAL ◽  
...  
Keyword(s):  
Sex Differences ◽  
Life History ◽  
Reproductive Strategy ◽  
Egg Production ◽  
Gonadosomatic Index ◽  
Life History Strategy ◽  
Minimum Size ◽  
Small Scale ◽  
Female Size ◽  
Dentex Dentex

Common dentex Dentex dentex is an iconic endangered species in the Mediterranean where is a sought after target species for small-scale, recreational and spearfishing fisheries. The reproductive biology of D. dentex in the natural environment is poorly known; therefore the reproductive strategy of the species was assessed by combining reproductive traits with the growth characteristics (estimated from length-at-age data), the size/age of sexual maturity and the energetic dynamics. A total of 358 wild fish were sampled on Mallorca Island (W Mediterranean) from March 1996 to June 1999 with a 19 to 84.7 cm total length (LT) range. The sex ratio was skewed towards females (1.361) albeit the length composition was not different between sexes (p = 0.551). Three young immature individuals (< 28 cm LT, 0.8% individuals) were rudimentary hermaphrodites supporting the late gonochoristic species classification. The age composition determined from sagitta otolith interpretation ranged from 0 to 26 years (yr). Concerning growth, between sex differences in von Bertalanffy parameters were not relevant, even after accounting for potential between-year differences. The most noticeable difference was found for L∞ (64.7 cm for females versus 61.6 for males) but even in this case, the bayesian credibility interval of between-sex differences included zero.  Maturity ogives at size and age showed that females achieved 50% maturity at 34.9 cm LT and 3.3 years, while males did at 33.8 cm LT and 2.5 years. The onset of gonad developing phase took place in December, while it progresses until April. The spawning peak was in April and May for both sexes. A generalized linear model showed that female size didn’t affect significantly the spawning season, whilst there was a strong seasonality in the spawning. Most of the evidences showed that fecundity is likely determinate, with an asynchronous oocyte development before spawning and a clear ovarian bimodal organization after the onset of spawning. Female weight explained 84% of the observed variance for fecundity. The gonadosomatic, hepatosomatic and condition indexes varied significantly with the reproductive season for females and only the gonadosomatic index for males. Storage in muscle seemed to be the primary source of energy for reproduction, although liver appeared to play a short-term role in egg production, suggesting a combination of capital and income breeding. The results indicate that the life history strategy of common dentex possess consist on maturing well before reaching maximum size, investing in growth after maturation, and therefore the reproductive effort is distributed through a longer lifespan and related with the size attained after maturation. At present no management measures are directed to D. dentex; given its life history strategy we suggest that a slot limit should be implemented, i.e. a minimum and a maximum landing size, with a minimum size of 35 cm. The upper threshold, to protect the higher reproductive potential of older and larger fish, should still be defined.

Preliminary results on the ovarian histology of rabbitfish Siganus rivulatus (Forsskal, 1775) in the southern Aegean Sea, Turkey

2020 ◽  
Vol 49 (3) ◽  
pp. 207-214
Author(s):  
Serhat Engin ◽  
Ozan Soykan ◽  
Hasan Cerim ◽  
Anıl Gülşahin
Keyword(s):  
Gonadosomatic Index ◽  
Aegean Sea ◽  
Early Summer ◽  
Small Scale ◽  
Annual Reproductive Cycle ◽  
Histological Changes ◽  
Recreational Angling ◽  
Fish Samples ◽  
Post Spawning ◽  
Siganus Rivulatus

AbstractThe study aimed to determine the annual reproductive cycle of Siganus rivulatusfi females based on monthly variation of the gonadosomatic index (GSI) and histological changes in gonads. A total of 240 fish samples were collected monthly from small-scale (trammel nets) and recreational (angling and pot fishery) fishing from Gökova Bay, the southern Aegean Sea, between July 2017 and June 2018. The length and weight of female fish varied from 10.8 to 26.1 cm with a mean length of 18.7 ± 0.2 cm and from 14.98 to 293.42 g with a mean weight of 91.1 ± 2.93 g. GSI values began to increase in May, peaked in June and gradually decreased in July, indicating that the spawning season was early summer. A total of 240 gonads were histologically examined. Granular, pinkish structure of eggs was observed primarily between April and June, which was consistent with the increase in the gonadosomatic index. Post-spawning follicles were determined in July. Values of the gonadosomatic index gradually decreased after August and they were minimal between September and November. During this period, ovaries were surrounded by immature oocytes at the chromatin and peri-nucleolus stages. These results revealed thatSiganus rivulatusstarted vitellogenesis in April and the gonadosomatic index peaked in June.

scholarly journals Spatially explicit analysis of gastropod biodiversity in ancient Lake Ohrid

2011 ◽  
Vol 8 (1) ◽  
pp. 175-188 ◽  
Author(s):  
T. Hauffe ◽  
C. Albrecht ◽  
K. Schreiber ◽  
K. Birkhofer ◽  
S. Trajanovski ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Water Depth ◽  
Scale Effects ◽  
Small Scale ◽  
Ancient Lakes ◽  
Depth Range ◽  
Ancient Lake ◽  
Lake Ohrid ◽  
Widespread Species ◽  
Neutral Processes

Abstract. The quality of spatial analyses of biodiversity is improved by (i) utilizing study areas with well defined physiogeographical boundaries, (ii) limiting the impact of widespread species, and (iii) using taxa with heterogeneous distributions. These conditions are typically met by ecosystems such as oceanic islands or ancient lakes and their biota. While research on ancient lakes has contributed significantly to our understanding of evolutionary processes, statistically sound studies of spatial variation of extant biodiversity have been hampered by the frequently vast size of ancient lakes, their limited accessibility, and the lack of scientific infrastructure. The European ancient Lake Ohrid provides a rare opportunity for such a reliable spatial study. The comprehensive horizontal and vertical sampling of a species-rich taxon, the Gastropoda, presented here, revealed interesting patterns of biodiversity, which, in part, have not been shown before for other ancient lakes. In a total of 284 samples from 224 different locations throughout the Ohrid Basin, 68 gastropod species, with 50 of them (= 73.5%) being endemic, could be reported. The spatial distribution of these species shows the following characteristics: (i) within Lake Ohrid, the most frequent species are endemic taxa with a wide depth range, (ii) widespread species (i.e. those occurring throughout the Balkans or beyond) are rare and mainly occur in the upper layer of the lake, (iii) while the total number of species decreases with water depth, the proportion of endemics increases, and (iv) the deeper layers of Lake Ohrid appear to have a higher spatial homogeneity of biodiversity. Moreover, gastropod communities of Lake Ohrid and its feeder springs are both distinct from each other and from the surrounding waters. The analysis also shows that community similarity of Lake Ohrid is mainly driven by niche processes (e.g. environmental factors), but also by neutral processes (e.g. dispersal limitation and evolutionary histories of species). For niche-based mechanisms it is shown that large scale effects such as type of water body or water depth are mainly responsible for the similarity of gastropod communities, whereas small scale effects like environmental gradients affect gastropod compositions only marginally. In fact, neutral processes appear to be more important than the small scale environmental factors, thus emphasizing the importance of dispersal capacities and evolutionary histories of species.

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).

scholarly journals Some reproductive characteristics of the blotched picarel Spicara maena (Perciformes: Centracanthidae) from Saros Bay, Northern Aegean Sea, Turkey

2019 ◽  
Vol 54 (2) ◽  
pp. 174
Author(s):  
Özgür Cengiz
Keyword(s):  
Reproductive Biology ◽  
Gonadosomatic Index ◽  
Aegean Sea ◽  
Reproductive Characteristics ◽  
Absolute Fecundity ◽  
Northern Aegean Sea

This study was carried out, monthly, in the Saros Bay (Northern Aegean Sea, Turkey) between January 2015 and December 2015. The gonadosomatic index (GSI) and absolute fecundity (Fa) of the blotched picarel (Spicara maena) were analyzed . The present study contributes to the reproductive biology of S. maena by reporting the first data about the fecundity of the species for the Aegean Sea

Reproductive biology of the black-striped pipefish Syngnathus abaster Risso, 1827 (Pisces: Syngnathidae) in the Aegean Sea of Turkey

2018 ◽  
Vol 47 (1) ◽  
pp. 67-74 ◽  
Author(s):  
Burcu Taylan ◽  
Gozde Ekin Tatarhan ◽  
Ozlem Aksoy ◽  
Mehmet Culha
Keyword(s):  
Reproductive Biology ◽  
Average Length ◽  
Gonadosomatic Index ◽  
Aegean Sea ◽  
Brood Pouch ◽  
Surface Water Temperature ◽  
Spawning Period ◽  
Total Length ◽  
Hydrated Oocyte ◽  
Length Relationship

Abstract The paper presents the results of research on the reproductive biology of Syngnathus abaster – a species distributed in Çandarli Bay. For this purpose, seine nets were collected from a depth of 0.5–2 m in 15 minute periods between April 2013 and March 2014, and a total of 185 individuals were sampled. It has been determined that 94 individuals (50.81%) were females, 79 were males (42.70%) and 12 were immature (6.49%). The sex ratio was 1:0.84. The average length values in female, male and immature individuals were 111.5 ± 7.35, 109.9 ± 11.08 and 79.8 ± 5.30 mm, respectively. The maximum mean surface water temperature is in spring and summer seasons. When Gonadosomatic Index (GSI%) values were examined, the spawning period of the species was indicated as spring and summer. Three groups of species were identified as maturing (diameter: 0.61–1.20 mm), mature (diameter: 1.21–1.70 mm) and hydrated oocytes (diameter: 1.71–2.10 mm) in ovaries of female individuals. The number of eggs in the brood pouch of pregnant male fishes was on average 48 (mean ± SD = 48 ± 14.09 eggs, range: 23–78 eggs). The hydrated oocyte/total length relationship was: y = 0.8651x – 84.332 (n = 14, r2 = 0.64) and the number of eggs/total length relationship in the brood pouch of pregnant males was: y = 1.0168x – 67.715 (n = 33, r2=0.58).

Reproductive biology and pathological changes of the Egyptian sole (Solea aegyptiaca, Chabanaud, 1927) from polluted waters of Abu-Kir Bay near Alexandria, Egypt

1994 ◽  
Vol 45 (7) ◽  
pp. 1181 ◽  
Author(s):  
SH Abdel-Aziz
Keyword(s):  
Reproductive Biology ◽  
Condition Factor ◽  
Gonadosomatic Index ◽  
Reproductive Period ◽  
Industrial Wastes ◽  
Pathological Changes ◽  
Potential Fecundity ◽  
Untreated Sewage ◽  
Males And Females ◽  
Polluted Waters

Solea aegyptiaca in Abu-Kir Bay becomes mature at 18 and 20 cm total length for males and females respectively and within two years of age for both sexes. Spawning occurs in winter (December-February). The sizefrequency distribution of oocytes more than 100 pm in diameter indicates that S. aegyptiaca is a determinate spawner and that an annual potential fecundity can be measured. Low gonadosomatic index and low potential fecundity, low condition factor (K), and histological anomalies of the ovaries of some mature females have been observed during the reproductive period. The presence of pollutants in Abu-Kir Bay sediments resulting from industrial wastes and untreated sewage may be responsible for this alteration in oogenesis and the consequent drop in fecundity.

scholarly journals Reproductive biology of Leporinus taeniatus Lütken (Pisces, Anostomidae) in Juramento Reservoir, São Francisco River basin, Minas Gerais, Brazil

2005 ◽  
Vol 22 (3) ◽  
pp. 565-570 ◽  
Author(s):  
Ralph G. Thomé ◽  
Nilo Bazzoli ◽  
Elizete Rizzo ◽  
Gilmar B. Santos ◽  
Thiago F. Ratton
Keyword(s):  
River Basin ◽  
Reproductive Biology ◽  
Gonadosomatic Index ◽  
Reproductive Period ◽  
Mature Stage ◽  
Gonad Maturation ◽  
Histological Techniques ◽  
Sao Francisco River ◽  
Fat Consumption ◽  
São Francisco River

The reproductive biology of the piau-jejo Leporinus taeniatus Lütken, 1875, an endemic species from the São Francisco River basin, was studied by using macroscopical and histological techniques. A total of 121 males and 94 females were captured quarterly, between March 2002 and February 2003 in the Juramento Reservoir. Females were larger than males, indicating sexual dimorphism. Stages of gonadal maturation were defined from histological analyses and gonadosomatic index. Peaks of maturing/mature and spawned/spermiated fishes has occurred in period December-February. L. taeniatus presented total spawning and group-synchronic development of the oocytes. The gonadosomatic index accompanied gonad maturation in both sexes, and coelomic fat presented lower levels during maturing/mature stage, indicating fat consumption during the reproductive period. Stomach repletion index presented higher values during spawned and spermiated stages, indicating greater food ingestion after the reproductive period.

scholarly journals Reproductive biology of the Neotropical electric fish Brachyhypopomus draco (Teleostei: Hypopomidae) from southern Brazil

2009 ◽  
Vol 7 (4) ◽  
pp. 737-744 ◽  
Author(s):  
Andrea B. Schaan ◽  
Júlia Giora ◽  
Clarice B. Fialho
Keyword(s):  
Sexual Dimorphism ◽  
Sex Ratio ◽  
Reproductive Biology ◽  
Water Depth ◽  
Electric Fish ◽  
Gonadosomatic Index ◽  
Reproductive Period ◽  
Weakly Electric Fish ◽  
Hepatosomatic Index ◽  
Southern Brazil

The reproductive biology of a population of the weakly electric fish Brachyhypopomus draco from southern Brazil is described. Information is provided on the establishment of the reproductive period in this species and its relations with environmental and feeding factors, as well as on the absolute and relative fecundities, spawning type, sex ratio and sexual dimorphism. The species exhibits a relatively long reproductive period, a relative fecundity of 0.173 oocytes per mg of female total weight, and fractional spawning. The sex ratio did not differ from 1:1 during all sampled months. Sexual dimorphism related to hypertrophy of the male's distal portion of caudal filament was observed and males grew to greater lengths than females. Male gonadosomatic index (GSI) was significantly related to water depth, oxygen saturation and temperature. Female GSI was significantly related to water depth and hepatosomatic index.

Sign in / Sign up

Export Citation Format

Share Document