scholarly journals Invasion dynamics of a non-indigenous bivalve clam; Venerupis aurea (Gmelin, 1791), in Lake Qarun, Egypt.

2017 ◽  
Vol 10 (2) ◽  
pp. 2056-2060
Author(s):  
Kandeel Hashem

The invasive clam Venerupis aurea is native to the Mediterranean Sea. The species has now become established in Lake Qarun, Egypt. This is the first record of the establishment of this clam in the Lake. The histograms of the length-frequency distribution indicated multiple consecutive cohorts and the species is able to establish self-sustaining population. Total weight increased relatively slower than shell length in summer. Isometric growth pattern was recorded in other seasons. Negative allometric growth pattern during summer may explain spawning. The female to male ratio is 1: 0.87. Sexual maturity is attained at 11.8 mm shell length in summer and 16.6 mm shell length in winter. Histological studies revealed two different stages in both male and female clams namely, immature and developing. The results from these preliminary studies have indicated that V. aurea is able to reproduce and survive in Lake Qarun and has an important impact in the local community of the Lake.

Author(s):  
Rosana Carina Flores Cardoso ◽  
Maria Lucia Negreiros-Fransozo

The allometric growth of Uca leptodactyla from two distinct subtropical estuaries on the Brazilian coast was evaluated concerning its growth pattern and size at onset of sexual maturity. Females attained maturity at similar sizes in both sites (4·1 mm of carapace length in Indaiá and 4·2 mm in Ubatumirim), while males differed slightly. They reached the size at sexual maturity of 5·3 mm of carapace length in Indaiá and 4·6 mm in Ubatumirim. Growth pattern is usually similar among crabs from distinct sites while size at sexual maturity is frequently different. However, in the case of U. leptodactyla it did not occur, probably due to the strong habitat similarity and intrinsic features of this species.


2020 ◽  
Vol 22 (2) ◽  
pp. 73-86
Author(s):  
Muyideen Owonire Lawal

Abstract This study investigated the growth pattern and length-weight relationship in Poecilia reticulata from the canal ecosystem of Lagos, Nigeria. A total of 2,400 fish specimens were caught, with total length ranging from 1.50 to 5.40 (3.30 ± 0.20) cm and weight ranged between 0.10 and 1.50 (0.63 ± 0.03) g. The length-frequency polygon showed four class intervals: 1.50-2.40 cm (51.29%); 2.50-3.40 cm (45.29%); 3.50-4.40 cm (3.25%); and 4.50-5.40 cm (0.17%). The value of “b” ranged from 1.3428-1.9863 which showed negative allometric growth, while the value of “r” ranged from 0.5 to 0.8. The mean K value was 1.05 ± 0.09 ‒ 1.62 ± 0.15.


2010 ◽  
Vol 8 (4) ◽  
pp. 835-840 ◽  
Author(s):  
Nelson F. Fontoura ◽  
Anamélia S. Jesus ◽  
Gabriel G. Larre ◽  
Juliana R. Porto

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.


2016 ◽  
Vol 106 (0) ◽  
Author(s):  
José R. S. Barradas ◽  
Isabel S. Lermen ◽  
Gabriel G. Larré ◽  
Thaís P. Martins ◽  
Nelson F. Fontoura

ABSTRACT A weight-length relationship was established for Corydoras paleatus (Jenyns, 1842) (Siluriformes, Callichthyidae) (n=596) from samples taken in November-December 2009 and March-April 2010, in Pinguela Lagoon (29°46'57"S; 50°11'16"W), Rio Grande do Sul, Brazil. The species showed a polyphasic allometric growth pattern, each stanza described by an independent power equation controlled by a switch function: W = a1Lb1 ∙ (1 + eRsc ∙ (L-SCP))-1 + a2Lb2 ∙ [1 - (1 + eRsc ∙ (L-SCP))-1] ; where W is the expected weight for a specific length L, a1 and a2 are the proportionality coefficients for stanzas 1 and 2, b1 and b2 are the allometric coefficients for stanzas 1 and 2, Rsc is the stanza changing rate for the switch function and SCP is the stanza changing point for the switch function. The stanza changing point was estimated as 5.28 cm, corresponding with the length at first maturity for this species Lmat (5.29 cm). Our data suggest that a complex growth pattern can be in nature, and perhaps not often identified because trends are obscured by natural variability.


2017 ◽  
Vol 4 (8) ◽  
pp. 301-305
Author(s):  
Matouke M. Moise

The investigation of length-weight relationship and condition factor are very relevant indices to ascertain the health of fish in the water body. Length-weigh relationship and condition factor of Hyperopisus bebe (Lacepede, 1803) (Actinopterygii: Osteoglossiformes: Mormyridae) in River Galma, Zaria, Kaduna State, Nigeria, were assessed. The mean length and mean weigh in male and female were 26.703 cm +/- 0.51 cm and 25.32 cm +/- 0.898 cm; 158.2 g +/- 10.1 g and 95.91 g +/- 9.26 g, respectively. The exponent or growth pattern 'b' values for male and female were 2.009 and 2.176. The condition factor for male and female were 0.59 and 0.83, respectively. The negative allometric growth pattern and poor condition factor might be due to the poor water quality in the fish ecosystem and should be regarded with concern.


Author(s):  
Edem, Edem Thomas ◽  
Ofunama, Preye ◽  
Eyo, Victor `Oscar

This study was carried out to evaluate the length-weight relationship, growth pattern and condition factor of the Silver catfish Chrysichthys nigrodigitatus from the Lower River Benue Makurdi, Nigeria. A total of 200 freshly caught specimens of C. nigrodigitatus were collected between July 2013 and September 2013 from the catches of the artisanal fisheries at landing points in Wadata Market, Makurdi. Results obtained showed that the “b” value for the males was 1.6067 while that of the females was 1.6791 and combined sexes 1.7371, indicating a negative allometric growth for this species. Correlation coefficient (r) obtained for males (0.9651), 0.9517 (females) and 0.9329 (pooled sexes) showed a positive significant relationship between length and weight of C. nigrodigitatus. Monthly mean condition factor (K), indicate that C. nigrodigitatus were in good physiological health condition. In conclusion, the baseline data on the length-weight relationship, condition factor of C. nigrodigitatus from the lower River Benue provided in this study is crucial in the sustainable management of this species in the River. Also, these findings will be useful in evaluating the population dynamics, stock and the aquaculture potential of C. nigrodigitatus for future purpose.


2020 ◽  
Vol 5 (2) ◽  
pp. 68-72 ◽  
Author(s):  
Henry Eyina Dienye ◽  
Olaniyi Alaba Olopade

Length-weight relationships (LWRs) and condition factor are important biological information to assess the growth pattern and wellbeing of fish species influenced by numerous abiotic and biotic factors. To date, no data on the LWRs and condition of mullets in Sombreior River, Niger Delta. Hence, this research was conducted to determine abundance, length–weight relationship and Fulton’s condition factor (K) of three species of fish belonging to family Mugilidae in Sombreior River, Nigeria. There were a total of 248 samples from five sampling stations for a period of months. Fish species were of various sizes ranging from 24.66±0.40 to 26.35±0.26cm in length and 141.41±6.30 to 161.56±5.87g in weight. For the three species, slope (b) values ranged from 2.18 to 2.68 indicating a negative allometric growth of all fish species. The mean condition factor ranged from 0.89±0.03 forsix Mugil cephalus to 0.93±0.03 for Parachelon grandisquamis while the coefficients of determination (R2) of the LWR regressions ranged between 0.64 (Neochelon falcipinnis) and 0.79 (Parachelon grandisquamis). It was concluded that the mullets in the Sombreior River had a negative allometric growth pattern and the condition is showing the species were in good state of well-being since mean K values are  greater than 1.


Author(s):  
Thomas Claverie ◽  
I. Philip Smith

Size at the onset of sexual maturity was determined in Munida rugosa based on allometric growth of chelipeds and abdomen, and on the proportion of ovigerous females. The variability of three different measurements of carapace length (CL) used previously for M. rugosa was also evaluated to minimize measurement error. Both sexes had symmetrical cheliped length and allometric cheliped growth over the size-range investigated, but males showed increased allometry beyond 22 mm CL. Females had greater positive allometry in abdomen width than males, but their size at maturity could not be precisely determined because sampled females were too large.


2019 ◽  
Vol 27 ◽  
pp. 121-132
Author(s):  
DA Nahar ◽  
MR Islam ◽  
MS Islam ◽  
S Jasmine ◽  
MMR Mondol

Growth, morphometry and length-weight relationships of the freshwater mussel Lamellidens marginalis (Lamarck, 1819) was studied during January 2014 and May 2015. Sampling was carried out monthly and a total of 560 specimens were collected from Rajshahi district, northwest of Bangladesh. The recorded length -breadth and length-width relationships were B = 0.179 + 0.475L and W = 0.196 + 0.3163L respectively. The length-total weight, length-wet tissue weight, length-dry tissue weight, length-shell weight, length-dry shell weight relationships were W = 0.1241L2.9066, W = 0.0524L2.7377, W =0.0116L2.7849, W = 0.0533L2.9178 and W = 0.0391L3.0386 respectively. Monthly b values of length-lengths and length-weights relationships indicated a negative allometric growth pattern except length-shell weights relationships which showed an isometric growth of the mussel. This study is the first report on growth pattern of Lamellidens marginalis from Bangladesh and the results would be useful for fishery managers to impose adequate regulations for a sustainable fishery management of this species in the freshwater ecosystem in Bangladesh. J. bio-sci. 27: 121-132, 2019


2016 ◽  
Vol 37 (4) ◽  
pp. 2123 ◽  
Author(s):  
Sérgio Carvalho ◽  
Luana Cortes Zago ◽  
Cleber Cassol Pires ◽  
Andressa Ana Martins ◽  
Rafael Sanches Venturini ◽  
...  

In this study, we evaluated the tissue composition, the ratios between different issues, and the allometric growth of tissues from the commercial cuts neck, shoulder, rib, and leg, and of the carcass of Texel lambs. Thirty uncastrated male lambs born from single calvings were used in this experiment. Lambs were weaned, confined individually, and distributed into five treatments with six replications. Each treatment consisted of a predefined slaughter weight (T23 – initial slaughter, T25, T30, T35, and T40). The proportion of bone decreased linearly in the shoulder, rib, and legs, but remained constant in the neck. The proportion of muscle decreased in the rib, whereas in the other cuts it remained constant. The percentage of fat increased as the slaughter weight of the lambs was increased, for all cuts. In all cuts and in the carcass, bone and muscle showed early growth (b < 1), whereas fat displayed late growth (b > 1). The proportion of bone decreased and fat increased linearly in the carcass, and the proportion of muscle was not influenced by the slaughter weight of the lambs. The muscle/fat ratio decreased in all cuts, and consequently in the half-carcass, as the slaughter weight was increased. The muscle/ bone ratio increased in the shoulder, rib, leg, and half-carcass, but there was no significant effect on the neck. The bone and muscle tissues showed early growth, whereas the fat had late growth in the different commercial cuts and carcass of Texel lambs. The tissue growth pattern of the shoulder may be representative of the allometric growth of the different carcass tissues. An increase in the slaughter weight of Texel lambs leads to a reduction of the muscle/fat ratio, due to the higher deposition of fat in the carcass of these animals.


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