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Preliminary Study on Spawning Period and Length at Maturity of Shortfin Scad, Decapterus macrosoma, (Bleeker, 1851, Perciformes:Carangidae) from the Coastal Waters of San Fernando, Romblon
Get PDFA preliminary study on spawning period, length at maturity, and main fishing grounds of Decapterus macrosoma (shortfin scad) collected from coastal waters of San Fernando, Romblon, Philippines were conducted. A total of 1,168 specimens were collected from July 2016 to December 2017. From these specimens, the minimum and maximum total lengths were 11.50 cm to 22 cm while its body weights ranged from 13 g to 100 g, respectively. D. macrosoma was capable of spawning whole year round. Two spawning peaks were observed (February and August to September) based on the monthly mean gonadosomatic indices. Male appeared to dominate female as evidenced by its sex ratios. The lengths at 50% maturity of female and male D. macrosoma were estimated at 15.29 cm and 17.22 cm, respectively. D. macrosoma was caught in volume through commercial ring net at a depth of about 150 m-200 m within the municipal waters. Coastal waters near barangay Canjalon and Agtiwa were identified as the main fishing grounds of D. macrosoma in San Fernando, Romblon. This initial data on spawning period may be used as a basis in implementing closed fishing season of D. macrosoma in the locality, and the length of maturity may as well be used for the allowable size of the capture of this species
Report: expanding the horizons
Get PDFNalini Nayak and Cornelie Quist reflect on the 7th Global Conference on Gender in Aquaculture and Fisheries (GAF7), held in Bangkok during 18-21 October 2018. Having been pioneers in the setting up of the Women in Fisheries (WIF) Programme of the International Collective in Support of Fishworkers (ICSF) 25 years ago, and having been actively involved since then in gender issues in fisheries, we were particularly attracted to GAF7. Its theme was ‘Gender in Fisheries and Aquaculture: Expanding the Horizons’. It promised a thinking that will go beyond descriptive papers on what women do in fisheries and gender-disaggregated data, to a more in-depth feminist analysis. We, therefore, decided to organize a workshop and share the long work of ICSF’s WIF Programme and the tools of feminist analysis of fisheries we had used. Our proposal to organise such a workshop aimed at deepening feminist perspectives in fisheries was accepted and hence we went to Bangkok
Fiji: Where’s the data?
Get PDFA recently-concluded meeting of the Women in Fisheries Network-Fiji calls for sex-disaggregated data on the participation of women in the fisheries sector
Monitoreo del virus del sindrome de la mancha blanca (WSSV) en muestras de langostino (Pleoticus muelleri) durante los años 2010 a 2014 en la Argentina
Get PDFLa pesquería de langostino (Pleoticus muelleri), una de las más importantes del Mar Argentino, superó en 2016 el 50% del valor total de las exportaciones pesqueras. La implementación y desarrollo de controles sanitarios son requisitos del comercio internacional. Entre los patógenos que afectan a los crustáceos se encuentra el virus del síndrome de la mancha blanca (White spot syndrome virus: WSSV) y, según lo establecido por la Organización Mundial de Sanidad Animal (OIE), la enfermedad es de declaración obligatoria. Debido a la necesidad de contar con datos científicos para establecer el estado sanitario del recurso respecto del WSSV, el objetivo del presente trabajo fue relevar en forma continua la infección viral en langostinos salvajes. Se trabajó con muestras capturadas durante 2010-2014 en áreas cercanas a puerto Rawson y el Golfo San Jorge. El total de 506 ejemplares analizados con la técnica de PCR anidada utilizando el Kit Comercial IQ2000TM WSSV, método validado por la OIE, resultaron negativos al virus. Se concluye que en los cinco años de monitoreo continuo no se evidenció presencia de WSSV en langostino. Este estudio ofrece una base de datos científicos que ayudaría a garantizar la calidad sanitaria y el comercio internacional de esta pesquería de interés comercial en la Argentina. Además, proporciona herramientas que permitirán proteger el producto ante posibles sanciones y barreras comerciales innecesarias
Investigation of physicochemical factors, chl-a and primary production in Mahshahr Creeks (Northwest Persian Gulf)
Get PDFThe study on physicochemical factors and primary production of the aquatic ecosystems is important to know the characteristics of the environment and capacity of recharge. Mahshahr Creeks are the most important creeks in the Northwest Persian Gulf, Iran. In this study, variations in physicochemical factors, chl-a, and primary production in creeks of Mahshahr, Zangi, and Moussa were evaluated for 2 months of every season of 2014. The following variables were analyzed: nitrate, phosphate, nitrite, silicate, temperature, salinity, DO, pH, conductivity, turbidity, light, chl-a, primary production and phytoplankton abundance. The maximum amount of chl-a (1.6 mg m^3) was observed in Moussa Creek in April while the minimum amount (0.1 mg m ^-3) was seen in Moussa in July. The highest (1.19 gc m^-2 day^-1) and lowest (0.1gc m^-2 day^-1) amount of primary production were observed at the entrance of Moussa Creek in April and in Zangi Creek in November, respectively. The maximum and minimum abundance of phytoplankton was observed in April and October, respectively in all study areas. The results of correlation test between the studied factors revealed that primary production has a significant relationship with nitrite, chl-a, phytoplankton abundance and light. Primary production in these creeks is relatively high in April and is attributed to the uptake of nutrients including nitrate and phosphate from shallow waters entering these creeks, sufficient light and suitable temperature, but in other months the production is low
First-phase Juvenile Rearing of the Sea Cucumber Holothuria scabra in Eastern Samar, Philippines
Get PDFExperiments were conducted to optimize the nursery rearing methods for the sea cucumber Holothuria scabra at the BFAR-GMFDC, Eastern Samar. The growth performance and survivorship of juveniles were compared in different locations, seasonality, stocking densities, and rearing media. For the experiments on location and seasonality, nursery rearing was conducted in Guiuan and in Salcedo, Eastern Samar during April-May, July-August, and September-October 2018. The mean total weight gain (TWG) and specific growth rate (SGR) of juveniles were significantly better in Guiuan (3.78 g and 13.09%.d-1, respectively) compared to Salcedo (1.997 g and 11.70%.d-1, respectively) (p 0.05). Predatory crabs and parasitic isopods (Cymodoce sp.) infiltrated the net cages in Guiuan, which increased the mortality of juveniles. Highest growth and survivorship were observed during dry months in April-May 2018 (TWG of 3.71 g, survival of 71.39%) but were lowest during the wet season in September-October 2018 (TWG of 2.26 g, survival of 70.89%). However, the growth and survival results did not significantly differ among different months (p>0.05). For the experiment on stocking density, juveniles stocked at 300 ind./cage had the highest growth (TWG of 5.19 g, SGR of 13.86%.d-1) while juveniles at 1000 ind./cage had the lowest growth (TWG of 1.28 g, SGR of 10.70%.d-1) (p 0.05). In terms of rearing medium, growth was better in floating net cages (TWG of 2.60 g, SGR of 11.67%.d-1) compared to indoor tanks (TWG of 0.18 g, SGR of 6.38%.d-1). However, indoor tanks yielded higher survival rate (67.83%) than floating net cages (56.11%) (p>0.05). Higher mortality in net cages was caused by intruding predators and fluctuations in water quality
Validation of Ultra High Pressure Liquid Chromatography (UHPLC) with Pre-column Derivatization Method for Quantitative Analysis of Histamine in Fish and Fishery Products
Get PDFA pre-column derivatization-ultra high performance liquid chromatographic (UHPLC) method is described for the determination of histamine in fish and fishery products. The homogenized samples were extracted with trichloroacetic acid (TCA) solution and derivatized with o-phthaldialdehyde. Histamine was separated using reversed-phase column and determined using UHPLC with fluorescence detection. The linear calibration range was 10 to 60 µg/mL with a correlation coefficient of 0.9993. Good recoveries were observed for the histamine under investigation at all spiking levels, and average recoveries were higher than 89% with a precision smaller than 8.46%. The detection and quantification limit were 2.7 and 8.3 µg/g, respectively. The uncertainty was estimated to be ± 0.45. The performance of the proposed method was checked with a proficiency test sample from the Food Analysis Performance Assessment Scheme (FAPAS) as external quality control; the resulting z-score was -0.2, which was found within acceptable range of -2 ≤ z ≤ 2. The results indicated that this HPLC method was reliable, sensitive, reproducible, and practical for the routine analysis of histamine in fish and fishery products
Detection of Taura Syndrome Virus (TSV) in Litopenaeus vannamei in the Philippines
Get PDFFarming of Litopenaeus vannamei in the Philippines was seen as a measure to increase shrimp production in the country. Taura Syndrome Virus (TSV) is a viral pathogen reported to be associated with Litopenaeus vannamei and other shrimp species. TSV outbreak impedes the production of Litopenaeus vannamei population and other species susceptible to the virus. Detection of TSV in L. vannamei in the Philippines calls for proper mitigation and appropriate actions for aquaculture and environmental management towards sustainable development. This study embarked on the detection of TSV using a purposive sampling method. Samples showing morphological symptoms of TSV such as redness of the carapace and pleopods and necrotic gill tissue collected from sites in Luzon and Visayas in the Philippines were processed. Viral RNA was extracted from the gills, the central area of infiltration and replication site of the virus. Complementary DNA (cDNA) was synthesized from the RNA templates and were subjected to RT-PCR under specific conditions using TSV specific primers against a positive control. Selected sites in the Philippines were proven to be positive of infection as they showed morphological symptoms and RT-PCR result in having a band at around 200 base pairs (bp). Percentage of prevalence results were obtained: Bulacan with 5 out of 15 samples (33%), Batangas with 7 out of 15 samples (47%), Bohol with 1 out of 15 samples (7%) and Cebu with 2 out of 15 samples (13%). The Batangas samples showed the highest prevalence of 47% (7 out of 15 samples) that were positive of the infection. This study reported the presence of TSV in L. vannamei in the country using morphological and molecular techniques
Effectiveness of Predator Control Set-up for Aquatic Pest Control in Earthen Ponds for Extensive Culture of Penaeus monodon (Fabricius, 1798)
Get PDFThe effectiveness of a conventional predator system for tiger prawn ponds consisting of a net barrier and fence interwoven around a modified pond gateway (set-up 1) was compared to an expanded system that directed water-borne pests to a fish compartment (set-up 2). The compartment had two confinement areas holding fifty, 5 g sea bass fingerlings and nineteen, 300-400 g tiger grouper juveniles separated by a fine mesh net gate secured to a sluice structure. Regardless of the set-up employed, after 88 days of culture, three pest categories were identified inside the ponds: prawn predators, opportunistic feeders, and benthic scavengers. Wet biomasses of fish pests were 1.92 kg and 2.12 kg, while that of mangrove snail was 29 kg and 80 kg in setups 1 and 2, respectively. Prawn length-weight frequency from 30% biomass manifested negatively skewed population curves with the highest frequency size range of 111-120 mm: set-up 2 had a smaller skewness value (-10.68) than set-up 1 (-20.64). A significant t-value of -1.39 (p < 0.10; df18 at t90) indicated that prawns raised in set-up 2 were larger than those grown under set-up 1. Finfish pests collected from set-up 2 were fewer than those in set-up 1, consisting predominantly of smaller (81-120mm) Megalops cyprinoides and Tilapia mossambicus: pests with total lengths below 81 mm were presumed to have been eaten by the sea bass and tiger grouper in the fish compartment. In both predator control systems, the period where tiger prawns are most vulnerable to predation pressure was during the first two months of culture, at lengths less than 111 mm and weights below 12.9 g
