scholarly journals Estimating size at first maturity (L50) from Gonadossomatic Index (GSI) data

2009 ◽  
Vol 7 (2) ◽  
pp. 217-222 ◽  
Author(s):  
Nelson F. Fontoura ◽  
Aloísio S. Braun ◽  
Paulo Cesar C. Milani
Keyword(s):  
Fish Species ◽  
Life Histories ◽  
Fish Stock ◽  
Stock Management ◽  
Neotropical Fish ◽  
Astyanax Fasciatus ◽  
Wide Scale ◽  
Scale Test ◽  
First Maturity ◽  
Size At First Maturity

Correct estimates of size at first maturity (L50) are useful for fish stock management and different methods have been proposed. In this study we propose the use of a modified logistic to estimate L50, including a variable asymptote (A). We also test the use of the Gonadossomatic Index (GSI) as a flag to establish the reproductive status of each female fish. The method is demonstrated using GSI data for four Neotropical fish species: Characiformes: Astyanax fasciatus (n = 473) and Oligosarcus robustus (n = 297); Siluriformes: Loricariichthys anus (n = 427) and Trachelyopterus lucenai (n = 195). The results were stable enough to propose this method be used for other fish species with different life histories and with a relatively unconstrained sampling programs. Nevertheless, a wide scale test program is desirable to identify any possible bias in this approach.

scholarly journals Reproduction and community structure of fish from winter shrimp bycatch from the Southeast Gulf of California

2017 ◽  
Author(s):  
Jorge de Jesus Tirado-Ibarra ◽  
Mariany Loya-Rodriguez ◽  
Jose Carlos Morales-Arevalo ◽  
Isabel Rosario Muñoz-Garcia ◽  
Jorge Saul Ramirez-Perez ◽  
...  
Keyword(s):  
Community Structure ◽  
Fish Species ◽  
Gulf Of California ◽  
Target Species ◽  
Importance Value Index ◽  
Importance Value ◽  
Shrimp Fishery ◽  
Average Size ◽  
First Maturity ◽  
Size At First Maturity

Shrimp fishery is one of the most important fisheries of the world. However, the low selectivity from trawl nets leads the capture of a large number of non-target species. Shrimp bycatch include a large number of fish and invertebrate species; of which fish species are the most abundant. The present study aims to determine the community structure as well as the average sizes at first maturity of the fish species from shrimp bycatch caught from industrial fisheries at the southeast of the Gulf of California from Sinaloa to Guerrero, Mexico; from January to March 2015. A total of 37 species of finfish were found; of which five were considered rare. The fish species with the highest Importance Value Index (IVI) were Pseudupeneus grandisquamis, Paralichthys woolmani, Lutjanus peru y Diapterus peruvianus. The average size at first maturity of 12 fish species was determined; nine of which have not been previously reported. Of the analyzed organisms 90% were in juvenile stage; including species with riverine and artisanal fisheries. The present study demonstrates the risk in marine populations of different non-target species due to the low selectivity of shrimp trawls.

scholarly journals Reproduction and community structure of fish from winter shrimp bycatch from the Southeast Gulf of California

2017 ◽  
Author(s):  
Jorge de Jesus Tirado-Ibarra ◽  
Mariany Loya-Rodriguez ◽  
Jose Carlos Morales-Arevalo ◽  
Isabel Rosario Muñoz-Garcia ◽  
Jorge Saul Ramirez-Perez ◽  
...  
Keyword(s):  
Community Structure ◽  
Fish Species ◽  
Gulf Of California ◽  
Target Species ◽  
Importance Value Index ◽  
Importance Value ◽  
Shrimp Fishery ◽  
Average Size ◽  
First Maturity ◽  
Size At First Maturity

Shrimp fishery is one of the most important fisheries of the world. However, the low selectivity from trawl nets leads the capture of a large number of non-target species. Shrimp bycatch include a large number of fish and invertebrate species; of which fish species are the most abundant. The present study aims to determine the community structure as well as the average sizes at first maturity of the fish species from shrimp bycatch caught from industrial fisheries at the southeast of the Gulf of California from Sinaloa to Guerrero, Mexico; from January to March 2015. A total of 37 species of finfish were found; of which five were considered rare. The fish species with the highest Importance Value Index (IVI) were Pseudupeneus grandisquamis, Paralichthys woolmani, Lutjanus peru y Diapterus peruvianus. The average size at first maturity of 12 fish species was determined; nine of which have not been previously reported. Of the analyzed organisms 90% were in juvenile stage; including species with riverine and artisanal fisheries. The present study demonstrates the risk in marine populations of different non-target species due to the low selectivity of shrimp trawls.

Ecosystem development in Lake Volkerak-Zoom: concept and strategy

1995 ◽  
Vol 31 (8) ◽  
pp. 239-243 ◽  
Author(s):  
W. Ligtvoet ◽  
S. A. de Jong
Keyword(s):  
Water Level ◽  
Fish Stock ◽  
Ecosystem Development ◽  
Optimal Conditions ◽  
Stock Management ◽  
Key Factors ◽  
Integrated Water Management ◽  
Ecological Concepts ◽  
Freshwater System ◽  
Water Level Management

In the 6000 ha Lake Volkerak-Zoom, a new freshwater system in the estuarine southwest of The Netherlands, biomanipulation is used as a tool in ecosystem development. The basic ecological concepts for ecosystem development are described. Key factors in the integrated water management are fish stock management and water level management, geared towards creating optimal conditions for northern pike, the dominant predator in mesotrophic waters. The main aspects of the water level management and the fish stock management are outlined.

scholarly journals Digestible energy of crude glycerol for pacu and silver catfish

2014 ◽  
Vol 44 (8) ◽  
pp. 1448-1451 ◽  
Author(s):  
Rafael Ernesto Balen ◽  
Patrick Nereu Tetu ◽  
Robie Allan Bombardelli ◽  
Paulo Cesar Pozza ◽  
Fábio Meurer
Keyword(s):  
Fish Species ◽  
Crude Glycerol ◽  
Energy Content ◽  
Biodiesel Production ◽  
Native Fish ◽  
Neotropical Fish ◽  
Digestible Energy ◽  
Silver Catfish ◽  
Glycerol Utilization ◽  
Good Potential

The increase in global biodiesel production is originating a glycerol surplus, which has no defined destination. An alternative to overcome this problem is its use as energy source in animal feeding. In Brazil, Pacu (Piaractus mesopotamicus) is one of the most farmed native fish species, whereas Silver catfish (Rhamdia quelen) is suitable for production in subtropical region. Considering little knowledge about crude glycerol utilization in feeds for Neotropical fish species, it was evaluated the apparent digestibility coefficients (ADCs) for energy of crude glycerol for P. mesopotamicus and R. quelen. The digestibility and digestible energy content of crude glycerol can be considered excellent even when compared to energy of common ingredients such as maize and wheat, presenting 0.97 and 0.89 of energy ADCs, and 15.2 and 13.95MJ kg-1 of digestible energy for Pacu and Silver catfish, respectively. In conclusion, crude glycerol is an energetic ingredient with good potential in Brazilian native fish diets.

scholarly journals Salivary Biomarkers in COVID-19 Patients: Towards a Wide-Scale Test for Monitoring Disease Activity

2021 ◽  
Vol 11 (5) ◽  
pp. 385
Author(s):  
Cecilia Napodano ◽  
Cinzia Callà ◽  
Antonella Fiorita ◽  
Mariapaola Marino ◽  
Eleonora Taddei ◽  
...  
Keyword(s):  
Real Time ◽  
Immunoglobulin A ◽  
Free Light Chains ◽  
Non Invasive ◽  
Salivary Biomarkers ◽  
Wide Scale ◽  
Scale Test ◽  
Control Disease ◽  
Rapid Laboratory ◽  
Operator Curve

The ongoing outbreak of coronavirus disease 2019 (COVID-19), which impairs the functionality of several organs, represents a major threat to human health. One of the hardest challenges in the fight against COVID-19 is the development of wide-scale, effective, and rapid laboratory tests to control disease severity, progression, and possible sudden worsening. Monitoring patients in real-time is highly demanded in this pandemic era when physicians need reliable and quantitative tools to prioritize patients’ access to intensive care departments. In this regard, salivary biomarkers are extremely promising, as they allow for the fast and non-invasive collection of specimens and can be repeated multiple times. Methods: We compare salivary levels of immunoglobulin A subclasses (IgA1 and IgA2) and free light chains (kFLC and λFLC) in a cohort of 29 SARS-CoV-2 patients and 21 healthy subjects. Results: We found that each biomarker differs significantly between the two groups, with p-values ranging from 10−8 to 10−4. A Receiving Operator Curve analysis shows that λFLC level is the best-suited candidate to discriminate the two groups (AUC = 0.96), with an accuracy of 0.94 (0.87–1.00 95% CI), a precision of 0.91 (0.81–1.00 95% CI), a sensitivity of 1.00 (0.96–1.00 95% CI), and a specificity of 0.86 (0.70–1.00 95% CI). Conclusion: These results suggest λFLC as an ideal indicator of patient conditions. This hypothesis is strengthened by the consideration that the λFLC half-life (approximately 6 h) is significantly shorter than the IgA one (21 days), thus confirming the potential of λFLC for effectively monitoring patients’ fluctuation in real-time.

scholarly journals Reproductive biology of Haemulon plumieri (Teleostei: Haemulidae) in Ceará state, Northeastern Brazil

2013 ◽  
Vol 73 (2) ◽  
pp. 391-396 ◽  
Author(s):  
RA Shinozaki-Mendes ◽  
J Santander-Neto ◽  
JRF Silva ◽  
FHV Hazin
Keyword(s):  
Reproductive Biology ◽  
Fishing Effort ◽  
Northeastern Brazil ◽  
Tropical Species ◽  
Stock Management ◽  
Western Atlantic ◽  
Total Fecundity ◽  
Maturation Stages ◽  
First Maturity ◽  
Management And Conservation

The Haemulon plumieri is a typical reef-associated and tropical species found in warm and temperate waters of the Western Atlantic. Due to the large fishing effort directed to H. plumieri, the knowledge about its reproductive biology is essential for correct stock management and conservation. The aim of this study was to characterise reproductive biology with a focus on its seasonal variation of gonadal maturation stages, first maturation size and fecundity. Specimens were monthly collected and a total of 119 females and 136 males were analysed. The reproductive cycle of Haemulon plumieri is seasonal, with higher activity between March and May. Size at first maturity (L50) was estimated at 16.86 and 18.55 cm for females and males, respectively. The total fecundity ranged between 17,816 and 120,333 mature oocytes per female and relative fecundity was 235 ± 63 oocyte.g−1 whereas batch fecundity varied between 20 and 25% from total fecundity. Since the species is widely caught, we suggest a closed season from March to May and to establish a minimum catch size of 18.5 cm for both sexes, since there is no evident sexual dimorphism.

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.

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