Now showing items 1-13 of 13

    • Article

      Accumulation and tissue distribution of radioiodine (131I) from algal phytoplankton by the freshwater clam Corbicula manilensis 

      MLA Cuvin-Aralar & RC Umaly - Bulletin of Environmental Contamination and Toxicology, 1991 - Springer Verlag
      Radioactive wastes discharged from establishments involved in the use of radioisotopes such as nuclear powered industries, tracer research and nuclear medicine are a potential public health hazard. Such wastes contain radionuclides, particularly Iodine-131 (131I), produced in fission with a yield of about 3%. It is a beta emitter (Bmax = 0.61MeV); it also emits gamma photons. It has a short half-life (8.04 d) (Dutton 1975), hence it is difficult to detect unless accumulated by indicator organisms.

      Radionuclides in waste waters are known to be taken up by molluscs such as mussels (Van der Borght and Van Puymbroeck 1970; Fowler et al. 1975; Hetherington et al. 1976; Helt et al. 1980; and Sombrito et al. 1982), oyster (Romeril 1971; Cranmore and Harrison 1975) and clams (Cuvin and Umaly 1988).

      This study aims to determine the uptake of 131I from algal phytoplankton (Choroococcus dispersus) fed to the freshwater clam Corbicula manillensis as well as the organ/tissue distribution. The results will be compared with our previous study on 131I uptake from water by the same clams (Cuvin and Umaly 1988).
    • Book

      Breeding and seed production of the giant freshwater prawn (Macrobrachium rosenbergii) 

      MLA Cuvin-Aralar, MA Laron, EV Aralar & UC de la Paz - 2011 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Series: Aquaculture extension manual; No. 52
      An extension manual describing biology, broodstock management, hatchery and nursery operations, feeding management, packing and transport, and health management of the giant freshwater prawn.
    • Article

      Culture of Macrobrachium rosenbergii (De Man 1879) in experimental cages in a freshwater eutrophic lake at different stocking densities 

      ML Cuvin-Aralar, EV Aralar, MA Laron & W Rosario - Aquaculture Research, 2007 - Blackwell Publishing
      Macrobrachium rosenbergii (de Man 1879) juveniles (0.4 g) were cultured in experimental cages (L × W × H: 2.5 × 1 × 1 m) in Laguna de Bay, the largest lake in the Philippines. The following stocking densities at four replicates each were used: 15, 30, 60 and 90 prawns m−2 of cage bottom. The mean sizes at harvest after 5 months of culture ranged from 14.3 g for the highest stocking density to 26.3 g for the lowest. The mean size at harvest, daily growth rate and size class distribution were significantly influenced by stocking density, with those at the lowest stocking density showing significantly better growth and overall proportion of larger prawns. Heterogeneous individual growth (HIG) was fairly evident in all treatments. The percentage of blue-clawed males was not influenced by treatment but the mean weight was significantly higher in the lower stocking densities. Both the percentage and mean weight of berried females were significantly higher in the lowest stocking density. Survival was the highest in the lower stocking densities (55.3%, 54.0%, 52.7% and 36.9% for 15, 30, 60 and 90 prawns m−2 respectively). Feed conversion ratio (FCR) improved with decreasing stocking density, ranging from 2.1 to 3. As expected, yield per cropping increased with stocking density and ranged from 450 to 1089 g m−2 yr−1 of actual cage area. Production values obtained in the cage cultured M. rosenbergii were comparable to or even higher than those reported from pond culture, given that the stocking densities used in this study were generally higher than in ponds. The results show that the farming of M. rosenbergii in cages in lakes is a viable alternative to pond culture and has the potential of improve aquaculture production in lakeshore fish farming communities.
    • Article

      Effect of dietary organic acid salts, potassium diformate and sodium diformate on the growth performance of male Nile tilapia Oreochromis niloticus 

      MLA Cuvin-Aralar, C Luckstaedt, K Schroeder & KJ Kühlmann - Bulletin of Fish Biology, 2011 - Verlag Natur & Wissenschaft
      The effect of two organic acid salts on the production performance of juvenile male Nile tilapia Oreochromis niloticus were studied in two separate experiments. In the first trial the fish (initial size: 7.84kg) were fed commercial feed supplemented with 0,3% potassium diformate (KDF) while in the second trial the fish (initial size: 16.48 kg) were fed diets supplemented with 0,3% sodium diformate (NDF). The control group for both trials used the same commercial fish feed with no supplementation. The feeding trials lasted for 74 and 78 days, respectively. Results showed that the supplementation of either KDF or NDF significantly improved growth and feed conversion of male Nile tilapia compared to the control group. The fish in the KDF treatment had a mean final weight of 51.4g and FCR of 1.81 compared to 45.4g and 1.97, respectively, for the control. Mean final weight and FCR of fish in the NDF treatment were 66.2g and 0.69, respectively, while those of the control were 58.7g and 0.77. The condition factor of the fish in both trials was not affected by treatment.
    • Article

      Embryonic development of the Caridean prawn Macrobrachium mammillodactylus (Crustacea: Decapoda: Palaemonidae) 

      MLA Cuvin-Aralar - Invertebrate Reproduction and Development, 2014 - Taylor & Francis
      The freshwater knob-tooth prawn Macrobrachium mammillodactylus is a commercially exploited species in the Philippines. To study the biology of this species, broodstock from the wild was collected, transported to the laboratory and kept in pairs in indoor polyethylene tanks for breeding. Eggs from berried females were sampled to follow the stages of embryonic development until hatching to zoea larva. It took 18.0 ± 2.1 days for the eggs to hatch at ambient water temperature between 25 and 28 °C. The morphological landmarks of development at the different stages (pre-cleavage, cleavage, blastula, pre-nauplius, post-nauplius and pre-hatching) of the live embryos are described. Incremental percentage staging was adopted from 0% at fertilization to 100% at hatching and were matched with corresponding morphological development. Egg volume increased significantly toward the mid-to-later stages of development. The eye index also showed a significant increase as the egg developed. The colour of the egg mass changed from light olive green to grey as the eggs progressed in development. The general pattern of development was comparable to other members of the genus Macrobrachium.
    • Conference paper

      Fish biodiversity and incidence of invasive fish species in an aquaculture and non-aquaculture site in Laguna de Bay, Philippines 

      MLA Cuvin-Aralar - In C Biscarini, A Pierleoni & L Naselli-Flores (Eds.), Lakes: The Mirrors of the Earth. Balancing Ecosystem and Human Wellbeing, 2014 - Science4Press
      Laguna de Bay is the Philippines' largest inland water with 900 km2 surface area. The lake has been assessed as hypereutrophic (Rohani and Roblo, 1984) to dystrophic (Barril and Tumlos, 2002). To make use of the lake's natural productivity a pilot aquaculture project started in 1971 (del Mendo and Gedney, 1979). The aquaculture industry in the lake rapidly developed, mainly using species not native to the lake. Since then, the lake has become a major source of fish in Metro Manila and the adjacent provinces.

      An assessment of the impact of aquaculture in the lake showed increased total finfish biomass in the lake; ecotrophic efficiency of phytoplankton increased; and the calculated total net primary production decreased by a factor of two compared to the pre-aquaculture period (de los Reyes, 1993). The dominant species cultured in Laguna de Bay are introduced species. After more than 40 years the lake is now populated with non-native species including species that are considered invasive and nuisance. Many of these species were deliberately introduced for aquaculture and there are those that were considered accidental introductions like ornamental fish cultured in ponds within the lake's watershed.

      To assess the impact of aquaculture in localized areas in the lake, a study was conducted to monitor diversity in the fisheries resources of the lake at two adjacent, but distinctly different sites: the West Cove (WC), an open fishery area, with no aquaculture and the East Cove (EC) which is an aquaculture site with cages for Nile tilapia, bighead carp, giant freshwater prawn.
    • Conference paper

      Incidence and causes of mass fish kill in a shallow tropical eutrophic lake (Laguna de Bay, Philippines) 

      ML Cuvin-Aralar, AE Santiago, AC Gonzal, CB Santiago, MR Romana-Eguia, SF Baldia & F Palisoc Jr. - In 9th International Conference on the Conservation and Management of Lakes. Conference proceedings, 2001 - Shiga Prefectural Government
      Mass fish kills in Laguna de Bay, the largest lake in the Philippines, has been reported as early as in the 1930’s. With the introduction of and development of aquaculture in this lake, considerable attention and concern was focused on the problem. Records of mass fish kill in the lake mainly from unpublished sources and reports from fisherfolk were reviewed and the causes categorized. The data covered the period 1972 to 1998. Among the commercially important fish species affected were milkfish (Chanos chanos), Nile tilapia (Oreochromis niloticus), bighead carp (Aristichthys nobilis), snakehead (Channa striata), catfish (Clarias macrocephalus and C. batrachus, Arius manilensis), silver perch (Terapon plumbeus) and goby (Glossogobius giurus). The first three species are widely used in aquaculture and the rest are important in open water fishery. Sixty percent of mass fish kill incidents were due to low dissolved oxygen with more than half of these cases associated with blue-green phytoplankton blooms. Fish kills due to pollution from agriculture and industries, fish pathogens and other causes are also discussed. The incidence of mass fish kill reached its peak between 1977 to 1986. Records show that the most number of fish kills (80%) occurred between the months of May to September. The lakeshore towns in the central arm of the lake had the highest incidence of fish kill reported with 46% and followed by the west arm of the lake with 38% of all fish kills recorded.
    • Article

      Mercury and selenium interaction: A review 

      MLA Cuvin-Aralar & RW Furness - Ecotoxicology and Environmental Safety, 1991 - Elsevier
      This paper reviews studies on mercury and selenium interaction. It includes the effects of selenium on mercury toxicity on the organism, organ/tissue, and subcellular levels. The paper also touches on possible mechanisms for the "protective action" of selenium against mercury toxicity and deals briefly with the synergism between the two elements.
    • Article

      Mercury levels in the sediment, water, and selected finfishes of Laguna Lake, the Philippines 

      MLA Cuvin-Aralar - Aquaculture, 1990 - Elsevier
      Monthly samples of sediment, water and commercially important species of fish, primarily Oreochromis niloticus and Chanos chanos , plus a few other species, were collected from the West Bay area of Laguna Lake, The Philippines from January to December 1987. Mercury levels were determined in all samples by cold vapor atomic absorption spectrophotometry. Results showed that sediment samples contained mercury levels ranging from 26.7 to 117 ppb. Mercury levels in water samples were low, ranging from below detectable to 0.5670 ppb. The mercury levels in the water were negatively correlated with conductivity and dissolved oxygen and positively correlated with turbidity. The mercury burden of the fish species samples was below the maximum permissible level set by the WHO and USFDA of 0.05 ppm. No direct correlation was observed between mercury levels in sediment and water, water and fish and sediment and fish.
    • Article

      Net mesh size affects production of giant freshwater prawn Macrobrachium rosenbergii cultured in lake-based cages 

      MLA Cuvin-Aralar, AG Lazartigue & EV Aralar - Journal of Applied Ichthyology, 2013 - Wiley
      Cage culture of freshwater prawns in open waters is prone to the entry of predators and competitors that particularly hamper production. This study was conducted to determine how smaller net mesh sizes to reduce entry of unwanted species inside the cages affects the production of Macrobrachium rosenbergii in lake-based cages. Juvenile prawns were stocked in cages (7 × 7 × 1.5 m) of two net mesh sizes at 10 individuals m-2 and cultured for 10 months in a shallow eutrophic lake in the Philippines. The two net mesh sizes were either 5 mm-mesh B-nets or and 1 mm-mesh Hapa nets. Each treatment had four replicates each and was fed based on biomass with commercially formulated feed. Monitoring of various production parameters was done during the two phases of culture: batch phase on days 63 and 127 and the selective harvest phase on days 187, 219, 253, 281 and 313, when the experiment was terminated. For the first 127 days of culture, the weight, percent weight increase, daily growth rate (DGR), specific growth rate (SGR), yield and feed conversion ratio (FCR) were significantly better in prawns reared in the Hapa compared to the B-nets. During the selective harvest phase the blue claw, orange claw and berried females were selectively harvested and the remaining prawns returned to the cages. After changes in stocking density through culling, ancova was used to compare the effect of mesh size with the total number of prawns returned to the cages as a covariate. Yield was significantly higher in the Hapa nets. Weight, DGR, SGR and FCR were also consistently higher in the Hapa nets, although not always significantly different. The overall better performance of prawns reared in the Hapa net cages was due to: (i) the reduction in the entry of predator and competitor species in the finer-meshed Hapa compared to the larger mesh B-net, (ii) more natural food trapped inside the Hapa cages, and (iii) a higher number of selectively harvested prawns, which decreased stocking density in the cages and improved growth. Use of small mesh size nets is recommended in the cage culture of M. rosenbergii in inland natural water bodies.
    • Conference paper

      Potential of cowpea (Vigna unguiculata L.) meal as an alternative protein source in diets for giant freshwater prawn (Macrobrachium rosenbergii, de Man 1879) 

      FA Aya, ML Cuvin-Aralar & RM Coloso - In MRR Romana-Eguia, FD Parado-Estepa, ND Salayo & MJH Lebata-Ramos (Eds.), Resource Enhancement and Sustainable Aquaculture Practices in Southeast Asia: Challenges in Responsible Production … International Workshop on Resource Enhancement and Sustainable Aquaculture Practices in Southeast Asia 2014 (RESA), 2015 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Growth trials were conducted to evaluate cowpea Vigna unguiculata (L.) meal as a potential protein source in diets for giant freshwater prawn, Macrobrachium rosenbergii (de Man 1879), reared in tank and lake-based cages. Five isonitrogenous (approximately 37% crude protein) and isocaloric diets were formulated where fish meal (FM) protein was replaced with 0%, 15%, 30%, 45% and 60% cowpea meal protein (or CP0, CP15, CP30, CP45, and CP60, respectively). Results of an 8-week tank trial showed that the final body weight (FBW), percent weight gain, specific growth rate (SGR) and survival of prawns were not significantly influenced by dietary treatments (P > 0.05), although the highest values, except for survival, were observed with CP45. In a lakebased cage trial that lasted for 16 weeks, prawns fed CP30 and CP45 had significantly higher FBW (13.1 and 14.4 g, respectively) compared to other treatment groups (P < 0.05). SGR (4.52 5.00%/ day), survival rates (53-77%), yield (98.5-116.5 g m-2) and feed conversion ratio (FCR; 2.0-2.7) were not affected by increasing levels of cowpea meal in the diets. Based on these results, cowpea meal can be considered as an alternative protein source in diets for M. rosenbergii.
    • Article

      Tissue distribution of mercury and selenium in minnows, Phoxinus phoxinus 

      MLA Cuvin-Aralar & RW Furness - Bulletin of Environmental Contamination and Toxicology, 1990 - Springer Verlag
      The protective effect of selenium against mercury toxicity has been extensively demonstrated in a number of studies (Burke eta]. 1977; Kasuya 1976). Since mercury uptake is not always diminished by the presence of selenium (Kim eta]. 1977) and neither does selenium enhance the elimination of mercury (Lucu and Skreblin i981; Cuvin and Furness 1988), these findings indicate that the mechanism for the observed protective action of selenium against mercury toxicity lie along different lines. It is believed that the rechanelling of mercury from one organ or tissue to another is one of the general mechanisms involved in the protective action of selenium against mercury toxicity. This is supported by the fact that one of the observed effects of selenium treatment on mercury-intoxicated animals is the apparent modification of the distribution pattern of mercury in the different organs and tissues. Decreased mercury levels in the kidney after selenium treatment has been demonstrated in rats by Chen eta]. (1974) and Potter and Matrone (1974).

      The following study aims to determine the effect of selenium on the distribution pattern of mercury in a common freshwater fish, the minnow Phoxinus phoxinus (Order Cypriniformes; Family Cyprinidae). Conversely, the effect of mercury on the tissue distribution of selenium will also be studied.