Yazar "Berber, Selcuk" seçeneğine göre listele
Listeleniyor 1 - 20 / 24
Sayfa Başına Sonuç
Sıralama seçenekleri
Öğe A Study on Determining the Ideal Stock Density of Freshwater Crayfish (Pontastacus leptodactylus) in Polyculture with Rice (Oryza sativa L.)(Kahramanmaras Sutcu Imam Univ Rektorlugu, 2019) Berber, Selcuk; Kale, Semih; Bulut, Musa; Izci, BahriThis paper aims to determine optimum stock density for rice-crayfish rearing in controlled environment. Juvenile freshwater crayfish (Pontastams ieptodady/us) obtained in the laboratory condition from female freshwater crayfish were stocked into rice planted artificial pond at different stock densit ies (25 individuals m(-2), 50 individuals m(-2), and 100 individuals m(-2)) for the assessment of paddy field areas in terms of field fisheries in Turkey. Results showed that the best survival rate (72%) and growth for juvenile freshwater crayfish in point of length and weight has been observed at the stock density of 25 individuals m(-2). In addition, statistically significant difference has been found between this stock density and the other stock densities (p<0.05). The maximum survival rate was observed as 72% at the stock density of 25 individuals m(-2). The results of this study are significantly different when compared with Other feeding researches on juvenile freshwater crayfish in Turkey. The stock density of 25 individuals m(-2) should be applied to gain maximum yield in rice- crayfish rearing experiments suggested as an alternative met hod for crayfish rearing. This paper. the first study on the investigation of different stock density for rice-crayfish rearing, will shed light on the further researches.Öğe A Study on the Relationships between Some Morphological and Reproductive Traits of the Turkish Crayfish, Astacus leptodactylus Eschscholtz, 1823 (Crustacea: Decapoda)(Taylor & Francis Inc, 2010) Berber, Selcuk; Yildiz, Harun; Ates, A. Suat; Bulut, Musa; Mendes, MehmetThis study was carried out to investigate relationships between some morphological and reproductive traits of the Turkish crayfish, A. leptodactylus, collected from a controlled irrigation lake in the Yenice province (Canakkale, Turkey), between July 2007 and June 2008. For this objective, two multivariate analysis techniques, namely canonical correlation analysis and multivariate multiple linear regression analysis, were used. The results of the canonical correlation analysis have shown that the morphological traits may be used to predict the changes in the reproductive traits. For instance, canonical correlation analysis results suggested that the egg weight and the number of eggs are related to the total length, carapace length, and carapace width. The results of multivariate multiple linear regression analysis, on the other hand, show a slightly different picture. Therefore, it is possible to conclude that both canonical correlation and multivariate regression results can be taken into consideration together when investigating the relations between two variable sets.Öğe Acute toxicity of Lambda-Cyhalothrin (Synthetic Pyrethroid) to the Juvenile and adult crayfish (Astacus leptodactylus Eschscholtz, 1823)(Medwell Journals, 2013) Berber, Selcuk; Turel, Selcuk; Kaya, HasanIn this study, the acute toxicity of lambda-cyhalothrin, a synthetic pyrethroid pesticides heavily used in the paddy fields, to the juvenile and adults of Astacus leptodactylus was investigated. The two different experiments, one for the juvenile (0.417±0.001 g) and one for the adult (39±2.2 g) crayfish were conducted. Acute toxicity tests was performed in 3 L glass jars for the juvenile and in aquariums for the adults. Acute toxicity tests with a static control and 6 different concentrations with 3 replications were tested. About 10 healthy individuals were placed in each. During the experiments, the water temperature was kept at 20°C and average pH was constant at 7.8. At the end of the 96 h experiments, the LC50 value of lambda-cyhalothrin for Astacus leptodactylus were found as 0.84 ng L-1 for the juveniles and as 0.207 ug L-1 for the adults. As a result, the heavily used lambda-cyhalothrin in the paddy fields was determined to be very toxic for juveniles and for adult of Astacus leptodactylus. © Medwell Journals, 2013.Öğe Age, Growth and Some Biological Characteristics of White Bream (Blicca bjoerkna L., 1758) in Uluabat Lake, in Northwestern of Anatolia(Academic Journals Inc, 2012) Sasi, Huseyin; Berber, SelcukIn this research, age, sex compositions, mortality, age-length, age-weight, length-weight relations, condition factors of white bream, Blicca bjoerkna (L., 1758), were determined from 183 specimens between April 2002 and March 2003 caught in Uluabat lake, in the northwest of Turkey. The age compositions of specimens were between 1-7 years and sex percentages were found as 50.27% for females and 49.73% for males. The mean forked length varied between 8.35 and 17.85 cm while mean weight ranged from 9.56 to 122.68 g. Growth of population was the most rapid at the first years of life afterwards growth ratio was slower. The weight of white bream increased allometrically for all sexes as seen b = 2.58. It was determined that the average condition factor of ages was between 1.62 and 2.51. The population has shown better growth performance than other habitats because the lake is low in latitude. We have given some of the population parameters and characters from Uluabat lake in northwestern part of Anatolia.Öğe An investigation of the reproductive properties of crayfish (Pontastacus leptodactylus (Eschscholtz, 1823) in Kocahidir reservoir(Parlar Scientific Publications, 2020) Boyalik, Fatih; Berber, SelcukThis study was carried out to investigate the relationships between some morphological and reproductive features of the Turkish crayfish, P. leptodactylus, collected from a controlled irrigation lake in the Kocahidir reservoir (Canakkale, Turkey), between July 2015 and June 2016. The sizes at sexual maturity were determined for both female and male individuals in the Kocahidir Irrigation Pond. For female crayfish, the total length of the smallest individual with mature egg ovaries was 83.54 mm and it weighed 15.5 g while the smallest individual that had fertilized eggs in the pleopods had a total length 91.89 mm weighed 23.78 g. The mean number of eggs detected in the female pereiopod was 192 ± 16, average egg diameter was 2.75 ± 0.013 mm, and the average egg weight was 0.012 ± 0.001 g. This study, explored the sexual differences and similarities in freshwater crayfish and their status in the Kocahidir Irrigation Pond was evaluated according to the populations at different localities. As a result, the-required strategies for their protection and to ensure a sustainable future for the freshwater crayfish population have been highlighted. © by PSPÖğe AN INVESTIGATION OF THE REPRODUCTIVE PROPERTIES OF CRAYFISH (PONTASTACUS LEPTODACTYLUS (ESCHSCHOLTZ, 1823) IN KOCAHIDIR RESERVOIR(Parlar Scientific Publications (P S P), 2020) Boyalik, Fatih; Berber, SelcukThis study was carried out to investigate the relationships between some morphological and reproductive features of the Turkish crayfish, P. leptodactylus, collected from a controlled irrigation lake in the Kocahidir reservoir (Canakkale. Turkey), between July 2015 and June 2016. The sizes at sexual maturity were determined for both female and male individuals in the Kocahidir Irrigation Pond. For female crayfish, the total length of the smallest individual with mature egg ovaries was 83,54 mm and it weighed 15.5 g while the smallest individual that had fertilized eggs in the pleopods had a total length 91.89 mm weighed 23.78 g. The mean number of eggs detected in the female pereiopod as 192 +/- 16, average egg diameter was 2.75 +/- 0.013 mm, and the average egg weight was 0.012 +/- 0.001 g. This study, explored the sexual differences and similarities in freshwater crayfish and their status in the Kocahidir Irrigation Pond was evaluated according to the populations at different localities. As a result, the required strategies for their protection and to ensure a sustainable future for the freshwater crayfish population have been highlighted.Öğe Antioxidant radical scavenging capacity and total carotenoid content of narrow-clawed crayfish (Pontastacus leptodactylus, Eschscholtz, 1823) in Atikhisar Reservoir (Çanakkale, Türkiye)(Walter De Gruyter Gmbh, 2023) Acarli, Sefa; Kizilkaya, Bayram; Vural, Pervin; Berber, Selcuk; Kale, Semih; Acarli, DenizIn this study, antioxidant radical scavenging capacity and total carotenoid content in the meat and shells of Pontastacus leptodactylus were investigated. Concerning the antioxidant scavenging effect, the highest IC50 values were found to be 388.77 mg g(-1) and 155.53 mg g(-1) for females and males in July and March, respectively. The mean IC50 values of the meat were calculated as 239.83 mg g(-1) and 105.21 mg g(-1) for females and males, respectively. The mean total carotenoid content in the meat was found to be 14.35 and 12.78 mu g g(-1) for females and males, respectively. The results indicated that crayfish meat had antioxidant radical scavenging capacity and was rich in carotenoid content.Öğe Cheliped loss and abnormalities of the narrow-clawed crayfish, Pontastacus leptodactylus (Eschscholtz, 1823) (Crustacea: Decapoda: Astacidae)(Soc Brasileira Carcinologia, 2024) Berber, Selcuk; Kale, Semih; Acarli, DenizHeterochely is an important phenomenon in decapod crustaceans. Nevertheless, it was rarely examined in freshwater crayfish. Therefore, the aim of this study was to investigate cheliped loss and abnormalities of the narrow -clawed crayfish, Pontastacus leptodactylus. The crayfish samples were captured using 17 mm mesh -sized fyke-nets from Atikhisar Reservoir in canakkale, Turkey between July 2020 and June 2021. The cheliped loss was classified and compared between sexes and length groups. The cheliped surface was calculated for each specimen for both the right and left cheliped. Results of the study indicate that the percentages of the sampled individuals were 5.46% for the right cheliped missing group, 5.23% for the left cheliped missing group, 10.37% for both chelipeds missing group, and 78.94% for both chelipeds present group. There was a statistical difference between cheliped loss and size groups (p < 0.05). Although cheliped loss is almost non-existent in low -size groups (10.0-29.9 mm), it reaches high values in the 40.0-69.9 mm size groups. The most intense loss occurs in the 40.0-49.9 and 50.0-59.9 mm size groups. It was determined that 10.69% of the sampled individuals examined had a single cheliped (10.03% female, 11.14% male). A statistically significant difference was found between cheliped loss and sex (p < 0.05). The percentage of female and male individuals with no chelipeds is 9.83% for females and 10.73% for males, and with both chelipeds it is 80.14% for females and 78.14% for males. While the number of abnormalities observed in chelipeds was higher in males, abnormalities in both chelipeds were higher in females. Moreover, it was found that cheliped loss significantly differed according to the months of collection (p < 0.05). Cheliped losses increased in July, August, and September when feeding was comparatively intense. In conclusion, the fact that the individuals were obtained alive, was an indication that the abnormalities detected did not significantly affect their vital activities directly. However, morphological abnormalities in the appendages, especially in the chelipeds, may impair their functional use compared to a healthy cheliped. This abnormal condition is assumed to share the disadvantageous limitations experienced by the absence of a cheliped.Öğe Comparison of Juvenile Astacus leptodactylus Growth Raised in Cages in Rice Fields to other Crayfish Juvenile Growth Studies(Central Fisheries Research Inst, 2018) Berber, Selcuk; Kale, SemihThe objective of this study was to determine whether the freshwater crayfish (Astacus leptodactylus Eschscholtz, 1823) rearing can be economically achieved in the rice fields using meta-analysis. For this purpose, 100 juvenile freshwater crayfishes were settled in each of three cages in the rice field and the survival and growth characteristics of juvenile freshwater crayfishes in the rice fields were evaluated for 68 days. The meta-analysis was performed to the present study and nineteen studies where researchers evaluated the survival and growth characteristics of juvenile freshwater crayfish. As a result, initial average length and weight of the individuals were 11.08 +/- 0.097 mm and 0.04 +/- 0.003 g, respectively. They reached to a total of 37.46 +/- 0.872 mm length and an average of 1.46 +/- 0.095 g weight after 68 days. During this period, the survival rate of the juvenile individuals was also determined as 64.67%. The meta-analysis showed that growth in length at a significant rate on the contrary growth in weight. In conclusion, it is suggested that freshwater crayfish rearing in rice fields is a new and applicable alternative method for growth of freshwater crayfish in Turkey.Öğe Depth and Seasonal Effects on the Settlement Density of Mytilus galloprovincialis L. 1819 in the Dardanelles(Medwell Online, 2010) Yildiz, Harun; Berber, SelcukThe seasonal pattern of recruitment of the mussel, Mytilus galloprovincialis, on artificial collectors, situated at four different depth (0.5, 4, 8, 12 m) in the Dardanelles. The presence of pediveliger mussels throughout the year and their abundance in march reflects the presence of spawning mussels throughout the year and the occurence of a major spawning period during beginning of spring. Different densities of mussel settlement were detected at the different depths. Mussel seed density was higher at 0.5 m (surface) and 4 m than 8 and 12 m throughout the year. Artificial collectors should be hung within the first 8 m (especially within 4 m) of the water column in order to exploit the highest settlement in the upper parts.Öğe Determination of traits some growth and morphometric of crayfish (Astacus leptodactylus Eschscholtz, 1823) at Manyas Lake (Balikesir)(Ege Univ, 2006) Berber, Selcuk; Balik, SuleymanThe aim of research was to determine traits of some growth and morphometric of crayfish live at Manyas Lake and the research was used 1118 crayfish (387 female, 731 male). In the research was found as 65.4 percent male, 34.6 female of crayfish thought investigation female and male ratios was of determined as to 0.53/1.00. Carapace length and totally weight of member of populations were between 15 mm - 78 mm; 0.5 g - 130.4 g and carapace length of female member and male member is 43.16 mm; 41.67 mm respectively. Metric traits of crayfish Totally Length, Carapace Length, Carapace Width, Abdomen Length, Abdomen Width, Totally Weight, Abdomen Weight, Carapace Weight, Cheliped Length, Chelae Length, Chelae Width, Chelae Weight and Carapace Length/Totally Length, Carapace Length/Abdomen Length, Carapace Width/Carapace Length, Abdomen Length/Totally Length, Abdomen Width/Abdomen Length, Abdomen Width/Carapace Width, Chelae Length/Cheliped Length, Chelae Width/Chelae Length, ratios were found significant between male and female statistically. Accordingly to results of regression analysis was found negative allometric growth of female crayfish, isometric growth of male crayfish, and negative allometric growth all of the populations.Öğe First Knowledge on Data Poor Stock: LWR and Condition Factor of a Recently Established Population of Atherina boyeri in Atikhisar Reservoir, Turkiye(Central Fisheries Research Inst, 2023) Kale, Semih; Berber, Selcuk; Acarli, Deniz; Gurkan, SuleFisheries management practices require reliable data for the assessment of data poor stocks. This paper reported the first knowledge on length-weight relationship (LWR) and condition factor of Atherina boyeri in Atikhisar Reservoir, Canakkale, Turkiye. A total of 1103 individuals of which 132 were immature was captured in June 2021. The sex ratio male to female was 1:1.75. The relationship between weight (W) and total length (TL), standard length (SL), and fork length (FL) were estimated as W=9E-06TL(2.9212), W=1E-05SL(2.9082), and W=9E-06FL(2.9495). A. boyeri exhibited a negative allometric growth. The mean of Fulton's condition factor of A. boyeri population in Atikhisar Reservoir was determined as 0.619 +/- 0.061. The mean Fulton's condition factor for female individuals were higher than the males' condition factor and the difference between sexes was statistically significant. The present study made available valuable information on the data poor stock by providing LWR and condition factor of A. boyeri in Atikhisar Reservoir, a new freshwater system for the very euryhaline amphidromous species. The findings of the present study will substantially contribute to the knowledge of the population dynamics of the commercially important species for fisheries managers and decision-makers to maintain sustainable population levels.Öğe First observation of the zebra mussel (Dreissena polymorpha (Pallas, 1771)) on the narrow-clawed crayfish inhabiting in some water sources of Turkey(Ege Univ, Fac Fisheries, 2018) Berber, Selcuk; Ates, A. Suat; Acar, SecilThe zebra mussel, Dreissena polymorpha (Pallas, 1771) is considered as a harmful invasive epibiont species for hydroelectric and nuclear power plants as it reduces or blocks water flow in the plant systems. Although D. polymorpha is reported that it cleans the water, increases water visibility, and filters out pollutants, it has likewise negative impacts on the population and size of some fish and aquatic species. In the present study, zebra mussels were observed for the first time. On the narrow-clawed crayfish living in some water sources in Turkey. Specimens were collected from two natural lakes (Cildir Lake, Egirdir Lake) and five ponds (Altinyazi Dam Lake, Keban Dam Lake, Kucukcekmece Lake, Karpuzlu Dam Lake, Kadikoy Dam Lake) in Turkey. Attachments of the zebra mussel to the different body parts of the narrow-clawed crayfish were documented in the present study. Cochran's Q test results showed that the numbers of mussels clinging to the different parts of the crayfish varied (P=0.000) (P < 0.001). The difference between the holding regions of zebra mussels on crayfish specimens may cause some adverse effects on the host. Particularly the intensive grip on the carapace partially obstruct the movement, feeding, mating, avoiding predators, and shelter. mussel individuals in the pleopodal region may have difficulty holding and transporting eggs. This study is the first report about the occurrence of D. polymorpha on Astacus leptodactylus in Turkish waters.Öğe Freshwater fish fauna and restock fish activities of reservoir in the dardanelles (canakkale-turkey)(2012) Sasi, Hüseyin; Berber, SelcukTurkey has, with geographic location including Istanbul and Çanakkale straits the system, 178,000 km in length streams, 906,000 ha of natural lakes, and 411,800 ha of dam lakes, and 28,000 ha of ponds due to richness inland waters which include freshwater fish. The fingerling fish (fry) were restocked approximately 250,000,000 in natural lakes, dam lakes and ponds for fisheries between years of 1979 and 2005. Canakkale has rich freshwater potential with 7 major rivers (Büyükdere, Karamenderes stream, Kavak brook, Kocacay stream, Sari{dotless}cay stream, Tuzla brook, Umurbey brook), 7 Dam Lakes (Atikhisar, Zeytinlikoy, Bayramic, Bakacak, Tayfur, Umurbey and Yenice-Gönen Dam lakes). In the studies, it has been determined that 15 fish species belonging to 6 families (Anguillidae, Atherinidae, Salmonidae, Cobitidae, Cyprinidae and Poecilidae) can be found in reservoirs. Fish restocking of the activities of the reservoir until today approximately 1,120,000 (Cyprinus carpio L., 1758) is introduced. In this study, the activity of Canakkale province in the fish restocking and reservoir exploiting possibilities were discussed in view of reservoir fisheries potential which is used insufficiently today.Öğe Meat Yield and the Length-Weight Relationships of the Narrow-Clawed Crayfish, Pontastacus leptodactylus (Eschscholtz, 1823)(Mekelle Univ, Coll Natural & Computational Sciences, 2023) Boyalik, Fatih; Berber, Selcuk; Kale, SemihThe present study investigated the length-weight relationships and meat yield of narrow-clawed crayfish, Pontastacus leptodactylus (Eschscholtz, 1823), in Kocahidir Irrigation Reservoir. Between July 2015 and June 2016, a total of 653 individuals (255 females and 398 males) were sampled, and their carapace lengths (CL), total lengths (TL), and total weights (TW) were measured. The female-to-male ratio for the entire population was found to be 0.64:1.00. The results showed that the CL of the narrow-clawed crayfish ranged between 37 and 90 mm (3979 mm for females and 37-90 mm for males), while the TW ranged from 10.10 to 165.61 g (11.13-90.01 g for females and 10.16-165.61 g for males). The TL of female individuals was 114.09 mm, with a weight of 40.43 g, while the TL of male individuals was 116.32 mm, with a weight of 53.45 g. The ratio of individuals above the minimum legal-size limit of 100 mm was determined to be 80.70% for the crayfish population in Kocahidir Irrigation Reservoir. Regression analysis indicated that the TL-TW and CL-TW relationships for female narrow clawed crayfish exhibited negative allometric growth, while males showed positive allometric growth in terms of the TL-TW relationship and isometric growth in terms of the CL-TW relationship. Isometric growth was observed in the whole population for both male and female individuals in terms of TL-TW and CL-TW characteristics. Female individuals with carapace lengths ranging from 43-82 mm had a chelae meat yield of 2.48%, an abdomen meat yield of 11.38%, and a total meat yield of 13.85%. Male narrow-clawed crayfish with carapace lengths ranging from 35 to 90 mm had a chelae shear meat yield of 4.13%, an abdomen meat yield of 10.52%, and a total meat yield of 14.64%.Öğe Modeling and predicting meat yield and growth performance using morphological features of narrow-clawed crayfish with machine learning techniques(Nature Portfolio, 2024) Gultepe, Yasemin; Berber, Selcuk; Gultepe, NejdetIn recent studies, artificial intelligence and machine learning methods give higher accuracy than other prediction methods in large data sets with complex structures. Instead of statistical methods, artificial intelligence, and machine learning are used due to the difficulty of constructing mathematical models in multi-parameter and multivariate problems. In this study, predictions of length-weight relationships and meat productivity were generated by machine learning models using measurement data of male and female crayfish in the narrow-clawed crayfish population living in Apolyont Lake. The data set was created using the growth performance and morphometric characters from 1416 crayfish in different years to determine the length-weight relationship and length-meat yield. Statistical methods, artificial intelligence, and machine learning are used due to the difficulty of constructing mathematical models in multi-parameter and multivariate problems. The analysis results show that most models designed as an alternative to traditional estimation methods in future planning studies in sustainable fisheries, aquaculture, and natural sources management are valid for machine learning and artificial intelligence. Seven different machine learning algorithms were applied to the data set and the length-weight relationships and length-meat yields were evaluated for both male and female individuals. Support vector regression (SVR) has achieved the best prediction performance accuracy with 0.996 and 0.992 values for the length-weight of males and females, with 0.996 and 0.995 values for the length-meat yield of males and females. The results showed that the SVR outperforms the others for all scenarios regarding the accuracy, sensitivity, and specificity metrics.Öğe Population structure and genetic analysis of narrow-clawed crayfish (Astacus leptodactylus) populations in Turkey(Springer, 2014) Akhan, Suleyman; Bektas, Yusuf; Berber, Selcuk; Kalayci, GokhanThe genetic differentiation among Turkish populations of the narrow-clawed crayfish was investigated using a partial sequence of cytochrome oxidase subunit I gene (585 bp) of 183 specimens from 17 different crayfish populations. Median joining network and all phylogenetic analyses disclosed a strong haplotype structure with three prominent clades diverged by a range between 20 and 50 mutations and substantial inter-group pairwise sequence divergence (5.19-6.95 %), suggesting the presence of three distinct clades within the Anatolian populations of Astacus leptodactylus. The divergence times among the three clades of Turkish A. leptodactylus are estimated to be 4.96-3.70 Mya using a molecular clock of 1.4 % sequence divergence per million years, pointing to a lower Pliocene separation. The high level of genetic variability (H (d) = 95.8 %, pi = 4.17 %) and numerous private haplotypes suggest the presence of refugial populations in Anatolia unaffected by Pleistocene habitat restrictions. The pattern of genetic variation among Turkish A. leptodactylus populations, therefore, suggests that the unrevealed intraspecific genetic structure is independent of geographic tendency and congruent with the previously reported geographic distribution and number of subspecies (A. l. leptodactylus and A. l. salinus) of A. leptodactylus.Öğe Prevalence, molecular identification and genotyping of the crayfish plague pathogen, Aphanomyces astaci in major narrow-clawed crayfish (Pontastacus leptodactylus Eschscholtz, 1823) populations from Türkiye(Sciendo, 2024) Akhan, Suleyman; Cagatay, Ifakat Tulay; Berber, Selcuk; Tastan, Busra; Tastan, Yigit; Dalar, TubaIntroduction Crayfish plague is considered the most important crayfish disease globally. It is caused by the fungus-like agent, Aphanomyces astaci. This study aimed to identify and determine the prevalence of A. astaci using PCR in narrow-clawed crayfish (Pontastacus leptodactylus) populations from across T & uuml;rkiye.Material and Methods A PCR was carried out with primers specific to the internal transcribed spacer region of the A. astaci pathogen on both telson and abdominal cuticle tissues from crayfish individuals from 41 different locations.Results Aphanomyces astaci was detected in the crayfish from 34 of the locations. Molecular diagnosis showed the prevalence rates of A. astaci to be between 0% and 68.2%. For 7 of the 34 locations, the strain of A. astaci was determined. Microsatellite analysis of tissue from individuals with positive PCR results revealed the A. astaci genotypes in seven populations. Genotype B was found to be the predominant genotype responsible for crayfish plague in Turkish crayfish populations. The Psl genotype (genotype B) was determined in six of the populations, and the As genotype (genotype A) was detected in only one.Conclusion Crayfish plague poses a significant threat to crayfish populations, necessitating the development of rapid, highly sensitive diagnostic methods. An understanding of the sensitivity of the PCR detection method and of the prevalence and genotyping of A. astaci in Turkish crayfish populations has been gained from this study.Öğe Relationships of benthic amphipod communities with environmental variables in the shallow waters of the Dardanelles(Walter De Gruyter Gmbh, 2012) Ates, A. Suat; Sezgin, Murat; Katagan, Tuncer; Ozdilek, H. Goksel; Berber, Selcuk; Kolsal, Secil; Bircan, CuneytThe structure of the benthic amphipod assemblage and its relationship with soft-bottom characteristics (particle size, organic matter, etc.) of the coastal waters at the depths of 0-5 m at the Dardanelles, including the Turkish Straits System, was studied. A SCUBA diver took benthos and sediment samples seasonally using a quadrate system of 30x30 cm as three transects from the 8 different stations between July 2008 and April 2009. A total of 3007 individuals belonging to 50 species was reported. Among these, Corophium acutum Chevreux, 1908 had the highest dominance value (Di%=22.18) and the lowest dominance value belonged to Dexamine thea Boeck, 1861 (Di%=0.03). The highest positive correlation (r(s)=0.57, p < 0.05) was observed between the gravel content (%) and the abundance (ind. m(-2)). The highest sand rate (99.59%) in the sediment was found at the Eceabat site. The lowest rate was at the Kepez Harbour station with a value of 73.01%. The highest H' value (1.53) was recorded at the Eceabat site, and the lowest H' value (H'=0.95) was recorded at the Gallipoli sampling station.Öğe REPRODUCTIVE EFFICIENCY OF THE NARROW-CLAWED CRAYFISH, ASTACUS LEPTODACTYLUS, IN SEVERAL POPULATIONS IN TURKEY(Brill Academic Publishers, 2009) Berber, Selcuk; Mazlum, YavuzStudies were carried out to evaluate the reproductive efficiency of the narrow-clawed crayfish, Astacus leptodactylus Eschscholtz, 1823, in three different populations in the lakes Apolyont, Iznik, and Manyas in Turkey. Crayfish were sampled monthly using fyke-nets of 34 mm mesh size from April 2002 until March 2003. The average number of pleopodal eggs (with their range), per female, was 200 +/- 12 (8-556) in Lake Apolyont, 202 +/- 13 (6-350) in Lake Iznik, and 257 +/- 13 (18-465) in Lake Manyas. The average number of ovarian eggs (with their range), per female, was 348 +/- 20 (126-630) in Lake Apolyont, 305 +/- 11 (162-465) in Lake Iznik, and 400 +/- 18 (205-776) in Lake Manyas. The average egg diameter and ranges were 2.23 +/- 0.004 (1.80-2.98) mm in Lake Apolyont, 2.53 +/- 0.003 (2.06-2.92) mm in Lake Iznik, and 2.65 +/- 0.027 (1.98-3.04) mm in Lake Manyas. Neither egg diameter nor egg weight increased with body size, but the variability of egg size and weight was high. No relationship was found between egg size and female crayfish size for any of the lakes. Mean size at maturity of female A. leptodactylus varied among the lakes. Females in Apolyont populations reached sexual maturity at a size of 64.3 mm TL, but spawning occurred only when females attained 82-128 mm TL, indicating that the mean minimum reproductive size was 82 mm TL in Lake Apolyont. Average female size was 88.7 mm (+/-SD 0.6; max. 142 mm; min. 48 mm; n = 154). In Iznik Lake, size at maturity of females was 78 mm TL, while spawning size was 83142 mm TL; average female size was 90.6 mm (+/-SD 0.5; max. 139 mm; min. 66 mm; n = 99). Finally, female size at maturity was 72.6 mm TL, and spawning size was 80-130 mm TL in Manyas Lake; average female size was 89.0 mm (+/-SD 1.1; max. 141 mm; min. 29 mm; n = 122). The total observed sex ratio (male/female) was found to be 1.00/0.53 in all three lakes together. Mature A. leptodactylus reproduce only once a year under natural conditions. No evidence was found in this study to suggest the occurrence of multiple spawnings.
