scholarly journals Some Aspect on the Biology of Pen Shell Atrina Pectinata (Linneaus, 1767) In Coastal Waters of Maqueda Bay, Philippines

2019 ◽  
Vol 2 (2) ◽  
Keyword(s):  
Coastal Waters ◽  
Total Mortality ◽  
Condition Index ◽  
Recruitment Pattern ◽  
Spawning Period ◽  
Growth Coefficient ◽  
Measurement And Analysis ◽  
Pen Shell ◽  
Atrina Pectinata

A Total of 379 pen shells Atrinapectinata were collected from February 2017 to January 2018 in the coastal waters of Maqueda Bay. Measurement and analysis of length and weight were done using FiSAT software. Population parameters were assessed to evaluate the stock status which includes the asymptotic length (L∞) and growth coefficient (K) to be 34.65 cm, 0.77 year−1 respectively. Specimens of A. pectinata reached a mean length of 20.98 cm. Length-weight relationship resulted to “negative allometric” 0.0462L2.6533 R2 = 0.7823; signifying pen shells growth was faster in length than on weight. The recruitment pattern was continuous over the year with one major peak during rainy season (July). In addition, the highest catch based on collected sampling date catch was during summer, which suggest as the peak season of the species in the area. Furthermore, the average catch annually of hookah diver was 17.69208. Higher condition index was recorded from April to May, September and January, indicating the high quality of pen shell meat and is recommended as the best period to harvest pen shell whereas June to August and October to December can be concluded as the spawning period of the pen shell and the ideal period to institute close season. Further analysis revealed that the pen shell was nearly facing overexploitation with the exploitation rate (E = 0.46) mainly due to lack of a minimum limit size and also due to an increase in the harvesting effort. The estimated total mortality (Z), natural mortality (M) and fishing mortality (F); 1.36 year−1, 1.01year−1 and 0.62 year−1, respectively. Using the mentioned (Z), (M), (F) and (E), the total population resulted to 84725.7 suggesting that half of the population has been exploited due to overfishing

scholarly journals POPULATION DYNAMICS OF THE EDIBLE ROCK OYSTER SACCOSTREA CUCULLATA (BORN, 1778) ALONG THE SOUTH-WEST COAST OF INDIA

2020 ◽  
Vol 67 (1) ◽  
Author(s):  
S. Yambem Tenjing
Keyword(s):  
Population Dynamics ◽  
Coastal Waters ◽  
South India ◽  
Total Mortality ◽  
Growth Coefficient ◽  
South West ◽  
Rock Oyster ◽  
Saccostrea Cucullata ◽  
Karnataka State ◽  
South West Coast

For the management of molluscan stocks, knowledge of various population parameters and exploitation level of the population are needed. The present study assessed the population dynamics on the rock oyster Saccostrea cucullata (Born, 1778) in Karnataka State, south India. The specimens of S. cucullata were collected from Baindur rocky beach at monthly intervals from June 2010 to May 2011. Asymptotic length (L∞) estimated was 57.8 mm and growth coefficient (K) was estimated at 1.4 year-1. The sizes attained were 45.30, 54.72 and 57.04 mm at the end of first, second and third years of age, respectively. Total mortality (Z) was 5.24 year-1. Natural mortality (M) and fishing mortality (F) were 1.40 and 3.84 year-1 respectively. The life span of S. cucullata was estimated as 2.5 years approximately. Exploitation level (E) was computed as 0.73, indicating that the fishery of S. cucullata in the coastal waters of Karnataka Is overexploited.

Estimating some population parameters and stock assessment of Dark Sleeper Odontobutis potamophila in the Gaosha River, Wuyuan County, Jiangxi Province, China

2017 ◽  
Author(s):  
Wu Bin Wang Haihua ◽  
Fu Huiyun Zhang Yanping
Keyword(s):  
Growth Parameters ◽  
Stock Assessment ◽  
Total Mortality ◽  
Landing Site ◽  
Jiangxi Province ◽  
Recruitment Pattern ◽  
Growth Coefficient ◽  
West Part ◽  
Exploitation Rate ◽  
Odontobutis Potamophila

A study was conducted to investigate the growth parameters, mortality and recruitment pattern of Odontobutis potamophila collected in the Gaosha river fish landing site, west part of Wuyuan County (Latitude: 29° 14' 29" N, Longitude: 117° 45' 49" E). O.potamophila were collected from November, 2013 to October, 2014. Growth parameters, asymptotic length (L) = 192mm and growth coefficient (k) = 0.22 year-1. Growth performance index(Ø’) =3.91, total mortality (Z) = 0.72 year-1, natural mortality (M) = 0.32 year-1, fishing mortality (F) = 0.40 year-1 and exploitation rate (E) = 0.55year-1.The estimated exploitation rate (E) has slightly exceeded the optimum value of E indicating this species was sustainable exploitation in the study area. The exploitation ratios were computed as Emax= 0.61, E10= 0.52, E50= 0.34. The length at first capture at 50%, (Lc) was 77 mm. The recruitment pattern of the species was found continuous all-round the year with one peak. The observation of the annual recruitment of O.potamophila found to occur from May to July. Steady biomass also increased with length class until 121-125 mm, and the total steady state biomass was found to be 2240 kg.

scholarly journals Population dynamics of Sardinella aurita (Val., 1847) within Ghana’s coastal waters

2017 ◽  
Vol 4 (3) ◽  
pp. 237-248
Author(s):  
Samuel KK Amponsah ◽  
Patrick K Ofori Danson ◽  
Francis KE Nunoo ◽  
Godfred A Ameyaw
Keyword(s):  
Mortality Rate ◽  
Coastal Waters ◽  
Total Mortality ◽  
Mesh Size ◽  
Reference Points ◽  
Recruitment Pattern ◽  
Commercial Fish ◽  
Management Interventions ◽  
Exploitation Rate ◽  
Sardinella Aurita

Following the declining stocks of Sardinella aurita within the coastal waters of Ghana, this study aimed at examining some population parameters of Sardinella aurita as a guide for managing this important stock sustainably. Length-frequency data of 717 samples were obtained from June, 2014 to January 2015 and measured for total length with the resultant data analyzed using FiSAT II. The asymptotic length (L∞) and growth rate (K) were 21.53 cm SL and 0.25yr-1 respectively. The theoretical age at birth (t0), longevity (tmax) and growth performance index (ϕ) were -0.74yr-1, 12 years and 1.849 respectively. Total mortality rate (Z), natural mortality rate (M) and fishing mortality rate (F) were 3.17, 0.76 and 2.41yr-1 respectively. The ages at first recruitment and first capture signaled future collapse of the stock, in the absence of proper management interventions. VPA outcome showed that mid- lengths of 11 cm and 12 cm SL experienced the highest harvesting rate with MSY estimated at 7733 tons. The recruitment pattern was continuous with two major recruitment pulses. Exploitation rate (Ecurr=0.76) was higher than the maximum exploitation rate (Emax=0.56), indicating unsustainable exploitation. Further, the fishing regime fell within the overfished stage based on the Quadrant Rule. For sustainable exploitation of this commercial fish species, implementation of relevant biological reference points through reduction in fishing efforts, creation of marine protected areas and mesh size regulation are urgently advocated.Res. Agric. Livest. Fish.4(3): 237-248, December 2017

scholarly journals Population Parameters of Two Commercially Important Species belonging to the Family Sciaenidae Encountered in the Coast of Ghana

2020 ◽  
pp. 21-29
Author(s):  
Samuel K. K. Amponsah ◽  
Selasi Yao Avornyo ◽  
Kofi Ferni Anyan
Keyword(s):  
Mortality Rate ◽  
Fish Species ◽  
Coastal Waters ◽  
Total Mortality ◽  
Population Parameters ◽  
Recruitment Pattern ◽  
Important Species ◽  
The Family ◽  
Exploitation Rate ◽  
Commercially Important

Population parameters for two commercially important fishes of Sciaenidae from the coastal waters of Ghana were assessed using length-frequency data obtained from August 2017 to June 2019. Samples of the assessed fish species were obtained through experimental fish trawl along the coast of Greater Accra, Ghana. Trawling was performed every quarter for an average of one hour at an average speed of 3.0 km/hr. In all, a total of 399 samples were measured and the obtained data were analyzed with FiSAT II. The assessed fish species included Pteroscion peli (165 samples) and Pseudotolithus senegalensis (234 samples). The asymptotic length (L∞) was 19.4 cm and 41.5 cm forPteroscion peli and Pseudotolithus senegalensis. Pteroscion peli and Pseudotolithus senegalensis recorded growth rate (K) of 0.48 and 0.50 per year respectively. Both assessed fish species exhibited continuous recruitment pattern with minor and major recruitment peaks. The total mortality rate (Z) was 1.86 and 1.63 per year for Pteroscion peli and Pseudotolithus senegalensis. The fishing mortality rate (F) was estimated at 0.66 and 0.63 per year for Pteroscion peli and Pseudotolithus senegalensis. The natural mortality rate (M) estimated for Pteroscion peli and Pseudotolithus senegalensis was 1.20 and 1.00 per year respectively. The exploitation rate (E) of Pseudotolithus senegalensis (0.39) and Pteroscion peli (0.36) respectively was far below the maximum exploitation rate (Emax), indicating under-exploitation of its fishery in the coastal waters of Ghana, hence the need to enhance the exploitation of these species.

Estimation of Population Parameters and Stock Assessment of Mastacembelus armatus in the Taojiang River, Xinfeng County, Jiangxi Province, China

2019 ◽  
Author(s):  
Wu Bin ◽  
Wang Haihua ◽  
Ma Benhe ◽  
Xu Xiandong ◽  
Zeng Qingxiang
Keyword(s):  
Growth Parameters ◽  
Stock Assessment ◽  
Total Mortality ◽  
Landing Site ◽  
Jiangxi Province ◽  
Recruitment Pattern ◽  
Growth Coefficient ◽  
Exploitation Rate ◽  
Mastacembelus Armatus ◽  
River Fish

A study was conducted to investigate the growth parameters, mortality and recruitment pattern of Mastacembelus armatus collected in the Taojiang River fish landing site, Xinfeng County. M. armatus were collected from March, 2018 to February, 2019. Growth parameters, asymptotic length (L¥) = 58.8cm and growth coefficient (k) = 0.13 year-1. Growth performance index(Ø2 ) =2.65, total mortality (Z) = 0.75 year-1, natural mortality (M) = 0.32 year-1, fishing mortality (F) = 0.43 year-1 and exploitation rate (E) = 0.57year-1.The estimated exploitation rate (E) has slightly exceeded the optimum value of E indicating this species was over exploited mainly due to fishing in the study area. The exploitation ratios were computed as Emax= 0.59, E10= 0.45, E50= 0.31. The length at first capture at 50%, (Lc) was 19.51 cm. The Steady biomass also increased with length class until 36.0-36.9 cm and the total steady state biomass was found to be 19.12 tons.

scholarly journals Estimation of Growth and Mortality Parameters for Two Penaeid Species of Tanzanian Coastal Waters

2019 ◽  
Vol 2 (1) ◽  
Keyword(s):  
Coastal Waters ◽  
Growth Parameters ◽  
Stock Assessment ◽  
Commercial Fishing ◽  
Recruitment Pattern ◽  
Growth Coefficient ◽  
Fenneropenaeus Indicus ◽  
Asymptotic Size ◽  
Metapenaeus Monoceros ◽  
Exploitation Rate

Assessment of the growth and mortality parameters of Fenneropenaeus indicus and Metapenaeus monoceros was conducted. Samples for the study were collected during two ship surveys conducted in February and June 2011 and from land-based surveys on two sites at Bagamoyo and Nyamisati, which was conducted between February 2011 and December 2012. Lengthbased stock assessment FiSAT II software package was used for assessment. The growth parameters which were asymptotic size (L∞), growth coefficient (K), total (Z) and natural (M) mortality, exploitation rate (E) and recruitment pattern were estimated. The results of analysis indicate that asymptotic size (L∞) for F. indicus was 44.1 mm CL for zone 1, zone 2 and Bagamoyo while Nyamisati was 48.3 mm CL. The growth coefficient (K) was 0.42, 0.83, 0.3 and 0.65 per year for zone 1, zone 2, Bagamoyo and Nyamisati respectively. The natural mortality (M) value was low in Bagamoyo and high in zone 2 while exploitation rate (E) and was high at Nyamisati area and low at Bagamoyo site. The study observed high exploitation levels on the two land-based sites (Bagamoyo and Nyamisati) despite the existing moratorium on prawn commercial fishing activities since 2008 hence seasonal closure for artisanal fishers was recommended.

Status of population dynamics of the Asian wedge clam, Donax scortum (Bivalvia: Donacidae): a first report from Asia

2016 ◽  
Vol 97 (8) ◽  
pp. 1635-1642 ◽  
Author(s):  
Yambem Tenjing Singh
Keyword(s):  
Population Dynamics ◽  
Coastal Waters ◽  
Sandy Beach ◽  
Stock Assessment ◽  
Total Mortality ◽  
Assessment Tools ◽  
Fishing Mortality ◽  
Population Parameters ◽  
Growth Coefficient ◽  
June July

For the management of mollusc resources, knowledge of various population parameters and exploitation level of the population of wedge clams are needed. Population dynamics on wedge clam, Donax scortum is still unknown in Asia. FAO-ICLARM Stock Assessment Tools (commonly known as FiSAT) was used for calculating population parameters of this species. The specimens of D. scortum were collected from Padukere sandy beach at monthly intervals from February 2009 to January 2010. Asymptotic length (Lα) was 70.88 mm and growth coefficient (K) was estimated at 0.64 year−1. The sizes attained by D. scortum were 33.51, 51.17, 60.49, 65.40, 67.99 and 69.36 mm at the end of first, second, third, fourth, fifth and sixth years of age, respectively. Density of clams ranged from 2 ind. m−2 (June, July and August) to 8 ind. m−2 (December). Biomass (total weight) of clams ranged between 10.084 g m−2 (August) to 185.100 g m−2 (December). Total mortality (Z) for D. scortum was 3.20 year−1. Natural mortality (M) and fishing mortality (F) were 0.64 year−1 and 2.56 year−1 respectively. Exploitation level (E) was computed as 0.80, indicating that the fishery of D. scortum in the coastal waters of Karnataka is overexploited.

scholarly journals Reproductive investment of the pen shell Pinna nobilis Linnaeus, 1758 in Cabrera National Park (Spain)

2017 ◽  
Vol 18 (2) ◽  
pp. 271 ◽  
Author(s):  
S. DEUDERO ◽  
A. GRAU ◽  
M. VÁZQUEZ-LUIS ◽  
E. ÁLVAREZ ◽  
C. ALOMAR ◽  
...  
Keyword(s):  
Stable Isotopes ◽  
Developmental Stages ◽  
Condition Index ◽  
Adductor Muscle ◽  
Spawning Season ◽  
Gonad Maturation ◽  
Anthropogenic Pressures ◽  
Spawning Period ◽  
Pinna Nobilis ◽  
Pen Shell

The spawning period can be a period of particular vulnerability for a species. In hermaphroditic species like the long-lived pen shell Pinna nobilis different costs could be associated with female, male or hermaphrodite stages. Here we evaluate gonad development in a population with few anthropogenic pressures and describe the timing and succession of developmental stages, determine the ratio of the sexes and the condition of the animals. We assess resource mobilisation and associated costs through the relationship between stable isotopes and condition indexes with reproductive parameters and evaluate the role of the adductor muscle as storage organ used in gonad maturation. In our study area only one spawning season is observed, starting in May and peaking in June-July. The onset of spawning coincides with water temperatures of 20 °C. Condition indexes drop during the spawning period and recover afterwards to reach pre-spawning values in November. Stable isotope signals are negatively related to the gonadal condition index, while the CN ratio shows a positive correlation with the same index. Additionally, the muscle condition index sharply decreases after the start of the spawning season, which suggests that P. nobilis uses the reserves stored in the adductor muscle for reproduction as in other Pinnidae species. Reproductive indices and stable isotopes ratios indicate ‘capital breeding’ as reproductive strategy of the pen shell. Decreased muscle force could mean a higher vulnerability during the summer period, coinciding with the peak in recreational activities involving poaching and anchoring.

scholarly journals Growth, mortality and yield of Atherina boyeri Risso, 1810 from Lesina lagoon (Adriatic Sea, Italy)

2020 ◽  
Vol 61 (2) ◽  
pp. 163-174
Author(s):  
Ermelinda Prato ◽  
Francesca Biandolino ◽  
Andrea Ruscito ◽  
Febo Lumare ◽  
Daniela Lumare ◽  
...  
Keyword(s):  
Adriatic Sea ◽  
Total Mortality ◽  
Recruitment Pattern ◽  
Growth Coefficient ◽  
Maximum Value ◽  
Lesina Lagoon ◽  
Exploitation Rate ◽  
Exploitation Status ◽  
Relationship Of ◽  
Probability Of Capture

Population structure, growth, age, mortality and exploitation status of Atherina boyeri, caught in the period from June 2013 to May 2014 in the Lesina lagoon (Apulia region, southern Adriatic) was studied. Samples were taken each month by using beach seines . The length–weight relationship of all sand smell specimens was described by the equation W=0.012*TL 3.10; (R2= 0.84). Population parameters including the asymptotic length (L∞) and growth coefficient (K) were assessed to evaluate the stock status. The recruitment pattern was modeled with a FiSAT routine. The asymptotic length (L∞) was 111.0 mm, while the growth coefficient (K) was 0.68 year−1. The growth performance index ((φ’) reached 3.92. The total mortality coefficient “Z”, the natural mortality coefficient “M” and the fishing mortality coefficient “F” were estimated as 2.24, 1.48 and 0.76 year-1, respectively. Exploitation rate for the population of A. boyeri in the Lesina lagoon estimated as 0.34 was resulted still lower than the predicted maximum value of Emax 0.59. The probability of capture indicated that L50 was of 55.57 mm, indicating that the stock of sand smelt in Lesina lagoon is not being over-fished.

Management and Status of Japanese Public Waters

1991 ◽  
Vol 23 (1-3) ◽  
pp. 1-10 ◽  
Author(s):  
Takeshi Goda
Keyword(s):  
Water Quality ◽  
Coastal Waters ◽  
Industrial Wastewater ◽  
Quality Standards ◽  
Water Bodies ◽  
Industrial Wastewaters ◽  
Quality Of Water ◽  
Japanese Rivers ◽  
Per Capita

The management and status of public water bodies in Japan is discussed. The environmental quality standards which have been set and the levels of compliance with these standards are shown. The water quality of Japanese rivers, lakes, reservoirs, wetlands and coastal waters is described, and eutrophication problems are mentioned. The effects of changes in population density and levels of recycling of industrial wastewaters on the quality of water bodies are discussed. Almost 75% of industrial wastewater is now recycled. Per capita availability of freshwater in Japan is comparatively low, and the construction of 530 dams, in addition to the 2393 dams already in operation, is planned. Irrigation effluents from paddy fields are a major factor which influences river water quality in Japan. The improvement of water quality using various methods is discussed.

Sign in / Sign up

Export Citation Format

Share Document