scholarly journals Population biology of shrimp Artemesia longinaris (Crustacea: Decapoda: Penaeidae) from the southern coast of Brazil

2010 ◽  
Vol 90 (4) ◽  
pp. 663-669 ◽  
Author(s):  
Rogério Caetano da Costa ◽  
Joaquim Olinto Branco ◽  
Irecê Farina Machado ◽  
Bruno Ribeiro Campos ◽  
Marcelo Gentil Avila
Keyword(s):  
Population Biology ◽  
Sexual Maturity ◽  
Migration Pattern ◽  
Lower Latitude ◽  
Breeding Period ◽  
Southern Brazil ◽  
Mean Size ◽  
Continuous Reproduction ◽  
First Maturity ◽  
Size At First Maturity

Size at morphological sexual maturity, sex-ratio, and the seasonal variation in abundance of the shrimp Artemesia longinaris Bate, 1888 were assessed off Pinheira Beach, Palhoça, Santa Catarina southern Brazil. Shrimp were collected monthly from November 2003 through to October 2004, in two areas that are customarily used by local traditional fishermen (27°52′–27°51′S and 48°33′–48°29′W). Of the total of 1099 specimens measured, 23.93% were males and 76.07% females. Mean size at first maturity (LM50) was estimated as 56.38 mm total length (TL) for males, and 70.34 mm TL for females. Females were significantly larger than males. Abundance of juveniles varied seasonally. A high predominance of juveniles in the areas sampled occurred in winter for both sexes, and in spring for females. In the summer and autumn, we observed a decrease in juveniles in both areas, mainly, area II. We suggest that the differential migration pattern of sexes during the reproductive cycle was the principal reason for the larger catch of females. The classical paradigm of continuous reproduction at lower latitude, with increased seasonality of the breeding period at higher latitudes, seems to apply to this species.

scholarly journals Fecundity, histomorphology of the ovary and size at first maturity of Neolissochilus hexagonolepis (McClelland) in Tamor River, Nepal

2020 ◽  
Vol 12 (3) ◽  
pp. 401-410
Author(s):  
Suren Subba ◽  
Vinod Kumar Mahaseth ◽  
Bharat Raj Subba ◽  
Shyam Narayan Labh
Keyword(s):  
Fishery Management ◽  
Fork Length ◽  
Reproductive Traits ◽  
Breeding Period ◽  
Absolute Fecundity ◽  
Fish Samples ◽  
Measuring Tape ◽  
The Mean ◽  
First Maturity ◽  
Size At First Maturity

Neolissochilus hexagonolepis (McClelland, 1839) is one among the notable species in snow-fed torrential rivers of Nepal. The present study attempts to investigate some reproductive traits of N. hexagonolepis, including the length at first maturity, fecundity and its relationships with biometric variables like lengths (TL, SL, and FL) and weights (TW and OW) of the fish in the mid-reaches of Tamor River, Nepal. A total of 109 fish samples were collected from the river. For each individual, total length (TL), standard length (SL) and fork length (FL) were measured in a fully stretched condition to the nearest 1mm using a measuring tape and graduated ruler, while total weight (TW) and ovary weight (OW) was measured using a digital balance with the precision of 0.01 g. The mean absolute fecundity (F) was 8356.44 ± 4612.59 and ranged from 2398.6 to 20160. SL was more significantly correlated with absolute fecundity (R2=0.59; p<0.001) than other body metrics. The results showed that female individuals of N. hexagonolepis attained the first sexual maturity at TL 32.9 cm. N. hexagonolepis exhibited a protracted breeding period with its ovaries passing through six different stages of maturation. The finding of the present study may serve as a protocol for fishery biologists and managers to promulgate adequate regulations for continual fishery management in the River Tamor, Nepal.

scholarly journals Reproductive Biology of Coral Catshark Atelomycterus marmoratus (Anonymous [Bennett], 1830) in Seribu Islands, Indonesia

2019 ◽  
Vol 20 (8) ◽  
Author(s):  
Selvia Oktaviyani ◽  
WANWAN KURNIAWAN ◽  
FAHMI
Keyword(s):  
Reproductive Biology ◽  
Gonadosomatic Index ◽  
Maturity Stage ◽  
Total Length ◽  
Mean Size ◽  
The Mean ◽  
First Maturity ◽  
The Relationship ◽  
Monthly Variations ◽  
Size At First Maturity

This study provides information on the reproductive biology of the coral catshark caught in the waters around Seribu Islands, Indonesia. A total of 257 coral catsharks were collected from February 2017 to January 2018. The total length of coral catshark ranged from 170 to 585 mm for females and 255-575 mm for males, respectively. The total weight of females ranged from 85 to 640 g and males from 100 to 620 g The sex ratio between females and males was 0.45 and it was not significantly different from the expected 1:1 ratio. The growth pattern of coral catsharks in Seribu Island was negatively allometric and the population was dominated by mature sharks. The mean size at first maturity was estimated to be 557 mm for females and 514 mm for males, based on to the relationship between the proportion between maturity stage and total length. The ovulation season was estimated occur from October to March, whereas September to April was mating season based on monthly variations of gonadosomatic index (GSI) values and the occurrence of egg cases in uterus.

scholarly journals Predicting size at first sexual maturity from length/weight relationship: a case study with an Amazonian catfish

2016 ◽  
Vol 14 (4) ◽  
Author(s):  
Tiago Magalhães da Silva Freitas ◽  
◽  
Vitor Hudson da Consolação Almeida ◽  
Luciano Fogaça de Assis Montag ◽  
Nelson Ferreira Fontoura ◽  
...  
Keyword(s):  
Growth Pattern ◽  
Sexual Maturity ◽  
Gonadosomatic Index ◽  
Gonadal Development ◽  
Visual Identification ◽  
Males And Females ◽  
Two Phases ◽  
First Maturity ◽  
Size At First Maturity

ABSTRACT Relationship between length and weight (LWR) is used to describe aspects concerning the life cycle of fish, but does not considers possible changes during the lifetime mainly due to the sexual maturation. Thus, this study aims to identify the size at first maturity of Auchenipterichthys longimanus (Siluriformes: Auchenipteridae) and infer if the reproductive engagement could change growth pattern, concerning the LWR. Estimates of the size at first maturity (L 50 ) were made by visual identification of gonadal development and through the gonadosomatic index (G SI ). L 50 was estimated as 12.5 cm for males and 13.0 cm for females when applied visual identification of gonads development. L 50 estimates increased to 13.05 cm for males and 13.7 cm for females when estimated from G SI values. LWR was adjusted by using a regular power function and through the polyphasic growth model, with proportionality and allometric coefficients changing in a two phases. The results indicate differences in the growth pattern concerning males and females, as well as polyphasic growth. The change in the growth pattern of the polyphasic LWR was estimated at 11.42 cm for males and 12.53 cm for females, suggesting that changes in the growth pattern can sign-out the attainment maturity in this catfish.

Size and age at sexual maturity in Adelomelon brasiliana (Neogastropoda: Volutidae) off Argentina

2008 ◽  
Vol 88 (1) ◽  
pp. 169-173 ◽  
Author(s):  
Maximiliano Cledón ◽  
Wolf Arntz ◽  
Pablo E. Penchaszadeh
Keyword(s):  
Sexual Maturation ◽  
Shell Length ◽  
Sexual Maturity ◽  
Tissue Samples ◽  
Gonad Tissue ◽  
Secondary Sexual Characters ◽  
First Maturity ◽  
Size At First Maturity ◽  
Secondary Sexual

Size at first maturity of Adelomelon brasiliana near Mar del Plata, Argentina, was established analysing gonad tissue samples and the secondary sexual characters. Age was determined through growth marks. Gonad matures after development of secondary sexual characters.Minimum shell length at sexual maturity is 107 mm in females and 102 mm in males. The shell length at which 50% of the animals are mature is 115.1 mm in females and 107.25 mm in males (approximatley 7 years of age). In males, penis matures before testis. All animals are mature beyond 125 mm in females and 115 mm in males, respectively (approximatley 8 years of age). The comparative late sexual maturation in this species makes the population quite sensitive to over-fishing.

scholarly journals Size at first maturity and maturity stages of Terapon jarbua (Forsskal, 1775) from Pondicherry Coast, India

2016 ◽  
Vol 4 (2) ◽  
pp. 385 ◽  
Author(s):  
R Nandikeswari
Keyword(s):  
Sexual Maturity ◽  
Maturity Stages ◽  
First Maturity ◽  
The Relationship ◽  
Size At First Maturity ◽  
Logistic Curves

Size at first maturity of Terapon jarbua was studied based on 114 male (14 to 28 cm in TL) and 140 female (14 to 32 cm in TL). The Logistic curves describing the relationship between the sexes and the proportion of 50% maturity (Lm50) were estimated at 20.8 cm in male and 21.8 cm in female of Terapon jarbua. The male reached 50% first sexual maturity at smaller lengths than female in this species. The gonads were classified into five maturity stages based on the size, colour and texture.  Month wise predominance of different stage of maturity deferred during different months.

scholarly journals Size, sex and maturity of the squid Lolliguncula diomedeae (Cephalopoda: Loliginidae) in the Gulf of Tehuantepec, México.

2015 ◽  
Vol 7 (1) ◽  
pp. 79-87
Author(s):  
María del Carmen Alejo-Plata ◽  
José Luis Gómez-Márquez ◽  
Jorge Eduardo Herrera-Galindo
Keyword(s):  
Sexual Maturity ◽  
Gonadosomatic Index ◽  
Reproductive Activity ◽  
Allometric Growth ◽  
Relationship Type ◽  
Length Relationship ◽  
Gulf Of Tehuantepec ◽  
Males And Females ◽  
First Maturity ◽  
Size At First Maturity

There is practically no information on the biology of Lolliguncula (Loliolopsis) diomedeae. We analyzed specimens caught in four shrimp fishing trips in the Gulf of Tehuantepec in 1999-2001, 2004 and 2006.Sexual maturity and gonadosomatic index (GSI) were used as indicators of reproductive activity. A total of 1 200 individuals were captured, 89% female. Females ranged from 35 to 97mm in mantle length (LDM),with a mode at 80mm and weights 2 to 30,9g; males 20,7 to 65mm LDM with a mode at 35-40mm and weights from 0,4 to 12g. Differences in the LDM and the PT between males and females were significant (KS, p<0,05). The sex ratio was 8:1 H:M (p <0,05). The weight-length relationship type is potential for both sexes, with a negative allometric growth.83% of mature females had high IGS values, in contrast to less than 20% of mature males. The size at first maturity (L50) indicates that males (42,7mm LDM) mature when shorter than females (74,5mm LDM). Maturity, IGS and oceanographic features of the Gulf of Tehuantepec indicate that L. diomedeae spawn there.

Size at first maturity of Brachidontes rodriguezii (d'Orbigny, 1846) from the South-western Atlantic Ocean

2016 ◽  
Vol 98 (3) ◽  
pp. 457-462 ◽  
Author(s):  
María Eugenia Torroglosa ◽  
Juliana Giménez
Keyword(s):  
Shell Length ◽  
Logistic Model ◽  
Sexual Maturity ◽  
Gonad Development ◽  
Female Gonad ◽  
Visceral Mass ◽  
Western Atlantic ◽  
Length Increase ◽  
First Maturity ◽  
Size At First Maturity

The size at first maturity of the bivalve Brachidontes rodriguezii was estimated in a population located in the northernmost limit of its distribution along Argentinean coast. Specimens were collected in two consecutive reproductive seasons from December 2011 to February 2012 and from December 2012 to February 2013. Individuals were evaluated using biometric and histological analyses of the gonads. This study intended to provide important information about the development of gonadal tissue according to shell length increase. Our results showed immature specimens lack gonads or exhibited groups of cells undergoing mitosis adjacent to the epithelium of the mantle and the tubules of the digestive gland. Male and female gonad development extended to mantle lobes and visceral mass as long as maturation occurred to reach sexual maturity. Using a logistic model our results showed that the size at which 50% of females were mature at a gonadal level was 7.05 mm in shell length; in males, 50% of the population were mature at 8.13 mm in shell length. The minimum shell length at which maturity was observed was 6.99 mm in shell length in females and 6.00 mm in shell length for males.

scholarly journals Can weight/length relationship predict size at first maturity? A case study with two species of Characidae

2010 ◽  
Vol 8 (4) ◽  
pp. 835-840 ◽  
Author(s):  
Nelson F. Fontoura ◽  
Anamélia S. Jesus ◽  
Gabriel G. Larre ◽  
Juliana R. Porto
Keyword(s):  
Growth Pattern ◽  
Sexual Maturity ◽  
Rio Grande ◽  
Allometric Growth ◽  
Rio Grande Do Sul ◽  
Power Equation ◽  
Length Relationship ◽  
First Maturity ◽  
Size At First Maturity

A weight/length relationship was established for Astyanax jacuhiensis (Cope, 1894) (n = 370) and Cheirodon ibicuhiensis Eigenmann, 1915 (n = 701), from samples taken monthly in Fortaleza Lagoon, Cidreira, Rio Grande do Sul, from December 1991 through November 1992. Both species showed a polyphasic allometric growth pattern, each stanza described by an independent power equation controlled by a switch function. For C. ibicuhiensis, this change in the growth pattern occurred at 2.948 cm standard length (SL), close to published sizes for the attainment of female maturity. The change in the growth pattern of A. jacuhiensis (SL = 3.481 cm) was below the predicted size at first maturity, and merits further investigation. Although not conclusive, our data suggest that a complex growth pattern is frequent in nature, and perhaps is not usually identified because trends are obscured by natural variability. Despite the increased complexity resulting from the application of a more-complex equation, the identification of a change in the growth pattern could indicate important aspects of fish biology, including the attainment of sexual maturity.

Leaf demography and decline of Panicum racemosum populations in coastal foredunes of southern Brazil

1991 ◽  
Vol 69 (7) ◽  
pp. 1593-1599 ◽  
Author(s):  
César S. B. Costa ◽  
Ulrich Seeliger ◽  
César V. Cordazzo
Keyword(s):  
Population Biology ◽  
Sand Dunes ◽  
Salt Spray ◽  
Nutrient Status ◽  
Southern Brazil ◽  
Leaf Demography ◽  
Growth Vigour ◽  
Sand Movement ◽  
Mobile Dune ◽  
Sand Deposition

We studied the effect of nutrient status and sand movement on the population biology of Panicum racemosum Spreng. over a 5-year period (1982–1986) on mobile, semifixed and fixed coastal foredune habitats in southern Brazil. The soils were deficient in nitrate, phosphate, and potassium (<0.5, 0.2–1.2, and 3–5 mg/kg, respectively) in all habitats, and a gradient of decreasing availability existed from the mobile to the fixed dunes. Half-lives of leaves were shorter in the fixed dune as compared with the mobile dune. Similarly, half-lives of leaves were shorter in summer than in winter. Experiments using cuttings of P. racemosum tillers showed that as P. racemosum plants grew, so did the deposition of sand on mobile foredunes. The mechanical deposition of sand itself did not stimulate P. racemosum growth. The deposition of saline sand provided a substrate that supported vertical growth of P. racemosum rhizomes and tillers and was a source of adsorbed nutrients. Also, active sand deposition limited the invasion of frontal dunes by other species. Panicum racemosum populations changed from "invader" to "mature" to "regressive" age states over a 5-year period, apparently in response to the spatial patterns of sand deposition and salt spray input. Key words: Panicum, leaf demography, growth vigour, sand dunes, temporal changes.

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