scholarly journals Population biology of shrimp Macrobrachium jelskii (Miers, 1778) (Decapoda, Palaemonoidea) at the Grande River at northwest of the state of Minas Gerais, Brazil

2012 ◽  
Vol 24 (3) ◽  
pp. 266-275 ◽  
Author(s):  
Samara de Paiva Barros-Alves ◽  
Ariádine Cristine Almeida ◽  
Vivian Fransozo ◽  
Douglas Fernandes Rodrigues Alves ◽  
José Carlos da Silva ◽  
...  
Keyword(s):  
Sex Ratio ◽  
Frequency Distribution ◽  
Population Biology ◽  
Abiotic Factors ◽  
Mesh Size ◽  
Minas Gerais ◽  
Reproductive Period ◽  
Length Frequency Distribution ◽  
Length Frequency ◽  
Monthly Basis

AIM: The population biology of the freshwater shrimp Macrobrachium jelskii was investigated here emphasizing the length-frequency distribution, sex ratio, reproductive period and juvenile recruitment. In addition, the abundance of individuals was correlated with the abiotic factors. METHODS: Samples were collected on a monthly basis from July 2005 to June 2007 along the river margin in shallow water of Grande River, at Planura region, State of Minas Gerais, Brazil (20º 09' S and 48º 40' W), using a trawl net (1.0 mm mesh size, and 2.0 m × 0.5 m wide). The fishing gear was handled by two people along the marginal vegetation of the Grande River in a course of 100 m, covered for one hour. In the laboratory, the specimens were identified, measured and sexed. RESULTS: A total of 2,789 specimens was analyzed, which corresponded to 1,126 males (549 juveniles and 577 adults) and 1,663 females (1,093 juveniles, 423 adults non-ovigerous and 147 ovigerous). The sex ratio differed significantly in favor of the females of M. jelskii (1:1.48; χ² = 103.95; p < 0.0001). The mean size of carapace length (CL) of females (6.32 ± 1.84 mm CL) was statistically higher than of males (5.50 ± 1.07 mm CL) (p < 0.001). The length-frequency distribution of the specimens revealed an unimodal pattern and non-normal distribution for males and females (W = 0.945; p < 0.01). No significant relationship between the abundance of M. jelskii and the environmental variables was observed (p = 0.799). CONCLUSION: The presence of ovigerous females and juveniles in the population suggests a continuous reproduction pattern and recruitment for M. jelskii at Planura region.

scholarly journals Preliminary biological data on Pomadasys incisus (Osteichthyes: Haemulidae) in the Aegean Sea, Greece

2008 ◽  
Vol 9 (2) ◽  
pp. 53 ◽  
Author(s):  
K. KAPIRIS ◽  
E. KALLIAS ◽  
A. CONIDES
Keyword(s):  
Sex Ratio ◽  
Frequency Distribution ◽  
Aegean Sea ◽  
Biological Data ◽  
Length Frequency Distribution ◽  
Length Frequency ◽  
Weight Relationship ◽  
Thermophilic Species ◽  
The Status ◽  
First Time

The present paper gives, for the first time, some biological data concerning Pomadasys incisus in theArgolikos Gulf (C. Aegean Sea). The bastard grunt (Pomadasys incisus) is a thermophilic species welladapted in the above area, but the status of fishery suggests an overexploitation. The sex ratio was infavour of males. The length frequency distribution did not differ between the sexes. Growth in weight wasestimated by means of the length-weight relationship. Reproduction seemed to take place in summer. Certainmorphometric characters appeared to be useful while comparing populations among the differentpopulations in the Mediterranean.

scholarly journals Investigating key biological parameters of Nile tilapia (Oreochromis niloticus L.) in a large Asian reservoir to better develop sustainable fisheries

2020 ◽  
Author(s):  
D. Beaune ◽  
J. Guillard ◽  
M. Cottet ◽  
K. Kue ◽  
R. Lae ◽  
...  
Keyword(s):  
Frequency Distribution ◽  
Oreochromis Niloticus ◽  
Nile Tilapia ◽  
Lao Pdr ◽  
Relative Yield ◽  
Growth Parameter ◽  
Mesh Size ◽  
Distribution Analysis ◽  
Length Frequency Distribution ◽  
Length Frequency

The Nile tilapia (Oreochromis niloticus) was introduced in Southeast Asia, such as in Thailand, in the mid-1960s for aquaculture purposes (Pullin et al., 1997; De Silva et al., 2004). The species was later promoted for aquaculture development in the early 1990s in Lao PDR (Garaway et al., 2000). In Lao People’s Democratic Republic (PDR), like in other countries, this exotic species is well established due to its self-reproduction (De Silva et al., 2004; CABI, 2018) facilitated by its particular life history traits and plasticity (Ishikawa et al., 2013). The species was then suspected to be introduced in the seventies in Laos and subsequently in the Nam Theun watershed where the NT2 Reservoir was impounded in 2008. Population parameters of this alien fish were investigated using the FiSAT II software with the most popular methods of bioparameters assessment to check their interchangeability within a same stock and the same year 2016. The length-at-age data analysis (using otoliths analysis, N = 258) gave slightly different results with the length frequency distribution analysis of fish landings (11 820 individuals). Furthermore, experimental fishing data provided irrelevant parameters due to insufficient representativeness of the sample size. The growth parameter K was estimated to be 0.23 year−1, with asymptotic length L∞ = 52.5 cm based on the length frequency distribution analysis with the fish landing data. According to these landing data, the total, natural and fishing mortality were Z = 1.41 year−1, M = 0.30 year−1 and F = 1.11 year−1. The exploitation rate E = 0.79 is over the Emax = 0.594 obtained by relative yield and biomass per recruit. This estimated stock of 165 tons (more than 700 000 tilapias) was characterized by high mortality (no population growth). These results showed that the population is overfished with too many juveniles caught (L50 = 210.4 mm; 50% mature stages at 295 mm). To maximize the yield per recruit, increase the biomass and sustain this fishery, enlarging the gillnet mesh size of the gill-net is recommended. This example highlights the variability of the parameters calculated from different methods and thus weaken worldwide and even inter-site comparisons. Despite this issue, the Growth Performances Indices (φ′) gathered into the literature can serve as baseline and confirmed the wide phenotypic plasticity of the species due to environmental factors. Analyses revealed difference between fast growing domesticated fish rose for aquaculture with φ′ higher to the tilapia growing in natural and challenging environments.

Age and growth pattern of the thin-lipped mullet Liza Ramada in the Eastern coast of Libya.

2016 ◽  
Vol 5 (06) ◽  
pp. 4620
Author(s):  
Manal M. Khalifa ◽  
Ramadan A. S. Ali ◽  
Abdalla N. Elawad* ◽  
Mohammad El. ElMor
Keyword(s):  
Frequency Distribution ◽  
Age Groups ◽  
Age Determination ◽  
Age And Growth ◽  
Eastern Coast ◽  
Growth Equation ◽  
Length Frequency Distribution ◽  
Length Frequency ◽  
Scale Reading ◽  
Von Bertalanffy Growth Equation

Age and growth characteristics of the thin-lipped Grey Mullet (Liza ramada) were investigated in Eastern coast of Libya. Aging was done by two methods: counting annuli on scales and by length frequency distribution, a total of 218 scales were studied for age determination, in addition of 334 fishes specimen for length frequency distribution reading. Four age groups were determined from scale reading, and five age groups from length frequency distribution methods, the parameters of the Von Bertalanffy growth equation for both sex of all individuals were estimated at 35.4 cm, 0.187 per year, -1.14 years and 2.4, for male were estimated at 35.7 cm, 0.17 per year, -1.367 and 2.3, for female were 38.6 cm, 0.156 per year, -1.383 and 2.4, for L∞, k and t0, and φ′, respectively.

scholarly journals Age, Growth and Ovarian Histology of Sardinella aurita (Valenciennes, 1847) in the South of Atlantic Moroccan Coast

2021 ◽  
Vol 21 (04) ◽  
pp. 191-204
Author(s):  
Ayoub Baali ◽  
Oum Keltoum Belhsen ◽  
Khalil Chahdi Ouazzani ◽  
Khadija Amenzoui ◽  
Ahmed Yahyaoui
Keyword(s):  
Frequency Distribution ◽  
Stock Assessment ◽  
Atlantic Coast ◽  
Age Groups ◽  
Age Determination ◽  
Length Frequency Distribution ◽  
Length Frequency ◽  
The South ◽  
Moroccan Coast ◽  
Sardinella Aurita

Otoliths reading and length frequency distribution were used for age determination and growth estimation of Sardinella aurita (round sardinella) stock of Southern Atlantic coast of Morocco. Both otoliths' method for age determination and Bhattacharya’s method for length frequency analysis showed five age groups. The growth performance index revealed that there is significant accordance among method of length frequency distribution and otoliths reading for stock assessment studies of Sardinella aurita stock in the south of Morocco. The microscopic observation of female gonads using histology method was investigated for the first time in our study area and confirms the presence of five principal stages of ovary of sardinella aurita: immature, maturing virgin and recovering spent, mature (or pre-spawning phase), spawning, post-spawning or spent. In addition, our results of the fecundity showed that the mean relative fecundity obtained is estimated at 193 ± 98 oocytes/g which is lower compared to those obtained in other areas in the Atlantic coast.

scholarly journals Seasonal changes in size, sex-ratio and body condition of the damselfishChromis chromisin the central Mediterranean Sea

2014 ◽  
Vol 94 (5) ◽  
pp. 1053-1061 ◽  
Author(s):  
Claudia Bracciali ◽  
Susanna Piovano ◽  
Gianluca Sarà ◽  
Cristina Giacoma
Keyword(s):  
Population Structure ◽  
Sex Ratio ◽  
Body Condition ◽  
Seasonal Changes ◽  
Marine Protected Area ◽  
Reproductive Period ◽  
Rocky Shores ◽  
Central Mediterranean ◽  
Monthly Basis ◽  
Spawning Period

Chromis chromisis one of the most abundant fish species on the Mediterranean rocky shores. Acting as a by-pass of nutrients from the pelagic to the rocky littoral system, it plays an important role as a resource provider and has a relevant function in the community assemblage.Chromis chromishas many of the characteristics required of an indicator species (e.g. it is easy to recognize in the field, small sized, widespread and abundant). In this study we focused on individual size, sex-ratio and body condition in a damselfish population occurring in a central Mediterranean marine protected area. Fishing trials on a monthly basis (April–November) allowed us to assess seasonal changes in population structure. Fish were measured and weighed and a subsample was aged and sexed. On average, males were larger than females. The allometric coefficient,b, for the whole population was 2.99; the maximum age recorded was 7.5 yr. Before reproduction sex-ratio was close to parity (M:F 1:0.78), while a larger proportion of females was captured during the reproductive period. In conclusion, our results show that the population dynamics ofC. chromisis influenced by both sex and size. Since males and females have different behavioural strategies, and since the length of the spawning period is shorter in the smaller than in the larger-sized individuals, this is reflected in temporal changes observed in the population structure.

A population study of Galathea intermedia (Crustacea: Decapoda: Anomura) in the German Bight

2003 ◽  
Vol 83 (1) ◽  
pp. 133-141 ◽  
Author(s):  
Katrin Kronenberger ◽  
Michael Türkay
Keyword(s):  
Sex Ratio ◽  
Population Biology ◽  
Abdominal Segment ◽  
Morphological Characters ◽  
Adult Males ◽  
Length Frequency ◽  
Relative Growth ◽  
Frequency Distributions ◽  
Squat Lobster ◽  
Growth And Reproduction

The objectives of this study were to assess population biology and dynamics of the squat lobster Galathea intermedia. On the basis of nearly regular monthly samples taken with a 2-m beam trawl in the Helgoland trench (HTR) during the period of 1985 until 1992, sex ratio, length composition, relative growth and reproduction were studied. The overall sex ratio deviates significantly from 1:1 with 1[male ]:1·8[female] (P[les ]0·001). On average, sexes are equally large, but adult females attain a slightly larger size than adult males. No sex-specific differences in the length–weight relationship were found. Relative growth of the first abdominal segment is clearly of sexual-dimorphic character. On the basis of the length–frequency distributions, the life cycle of the HTR population lasts between one and two years. According to the appearance of ovigerous females and juveniles, reproduction and recruitment are clearly seasonal. Recruitment takes place between July and December. The main reproduction begins in April and ends in September, with a peak between June and August. A significant increase of specimens showing both male and female morphological characters, referred to as morphological hermaphrodites (P[les ]0·001), and males (P[les ]0·05) respectively, was detected.

scholarly journals Population structure and reproductive behavior of Sinaloa cichlid Cichlasoma beani (Jordan, 1889) in a tropical reservoir

2011 ◽  
Vol 9 (3) ◽  
pp. 593-599 ◽  
Author(s):  
Melgen A. García-Lizárraga ◽  
Francisco Enrique Soto-Franco ◽  
Javier Marcial de Jesús Ruiz Velazco-Arce ◽  
José Iván Velázquez-Abunader ◽  
Jorge Saúl Ramírez-Pérez ◽  
...  
Keyword(s):  
Population Structure ◽  
Sex Ratio ◽  
Multinomial Distribution ◽  
Mesh Size ◽  
Condition Index ◽  
Reproductive Period ◽  
Tropical Reservoir ◽  
Timing Of Reproduction ◽  
First Maturity ◽  
Size At First Maturity

The population structure and reproductive condition of the Sinaloa cichlid Cichlasoma beani from samples obtained from June 2000 to July 2001 were determined. Samples in the first week each month from the largest trader of tilapia in the Aguamilpa Reservoir in Mexico and were caught in gillnets (9.6 and 11.4 cm stretch-mesh size). Of 596 specimens, there were 427 males and 169 females; monthly sex ratio, frequency of lengths by the multinomial distribution, timing of reproduction, condition index, and size at first maturity was determined. Differences in the sex ratio and monthly totals were significant, favoring males, except for September 2000 and March 2001. From one (August 2000) to three modal groups (July 2000 and June 2001) were identified by size. There were no significant differences in standard length weight relationships by sex, which indicated that a shared model for both genders is appropriate, and isometric growth was detected. Based on the proportion of mature and partially matures fish, the main reproductive period was April through June; size at first maturity was 18.9 cm. Water temperature was not significantly related to the percentage of mature and partially matures Sinaloa cichlids or spawning. These findings provide information for regulating the Cichlasoma beani fishery in this region such minimum legal size and non-fishing period.

scholarly journals Pola pertumbuhan dan faktor kondisi ikan lemeduk (Barbodes schwanenfeldii) di Sungai Belumai Deli Serdang Provinsi Sumatera Utara

2017 ◽  
Vol 4 (1) ◽  
pp. 8
Author(s):  
Siti Aisyah ◽  
Darma Bakti ◽  
Desrita Desrita
Keyword(s):  
Frequency Distribution ◽  
Growth Pattern ◽  
Condition Factor ◽  
Length Frequency Distribution ◽  
Length Frequency ◽  
Growth Coefficient ◽  
Weight Relationship

Penelitian ini dilakukan di Sungai Belumai Kabupaten Deli Serdang Provinsi Sumatera Utara pada Bulan Mei dan juni 2014 di empat lokasi yang berbeda dengan menggunakan metode sensus. Tujuan dari penelitian ini untuk mengetahui aspek pertumbuhan (sebaran frekuensi panjang, hubungan panjang bobot, faktor kondisi dan koefisien pertumbuhan). Jumlah ikan lemeduk yang tertangkap adalah 55 ekor. Hasil penelitian menggambarkan bahwa populasi ikan didominasi oleh sebaran ukuran kelas panjang 174-194 mm. Hasil hubungan panjang berat menunjukkan bahwa pola pertumbuhan ikan bersifat allometrik negatif (b=2,565) dimana pertambahan panjang lebih cepat dibandingkan pertambahan berat. Nilai faktor kondisi ikan lemeduk (Barbodes schwanenfeldii) berkisar 0,946-1,059.This research was done in Belumai River Deli Serdang District North Sumatera Province. This research was conducted in May until June 2014 in four different locations by using census method. The purpose of this research is to know the aspect of growt (length frequency distribution, length-weight relationship, condition factor and growth coefficient). The number of lemeduk fish which caught were 55 fish. Result shown that the population is dominate by length frequency distribution 174-194 mm. Result length-weight relationship shown that growth pattern was allometric negative (b=2,565) where the length is faster growth than the weight. The condition factor of lemeduk fish was around 0,946-1,059.

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