Now showing items 1-20 of 66

    • Serial

      AQD Matters 2004 June 

      T Bagarinao - 2004 - Aquaculture Department, Southeast Asian Fisheries Development Center
    • Article

      Behavioural evidence for colour vision determined by conditioning in the purple mud crab Scylla tranquebarica 

      G Kawamura, TU Bagarinao, HS Cheah, H Saito, ASK Yong & LS Lim - Fisheries Science, 2020 - Springer Verlag
      Crabs and shrimps (order Decapoda) use colours in various tasks such as foraging and mate choice. Colour vision requires at least two types of photoreceptors with different spectral sensitivities. Previous physiological studies revealed that most crabs including Scylla mud crabs have a single visual receptor system, i.e. they are colour blind. We determined colour vision by means of a behavioural experiment on hatchery-produced and wild-captured purple mud crab Scylla tranquebarica in a roofed hatchery. Adult crabs (8-10 cm carapace width) were subjected to classical conditioning to associate a food reward with a blue or a green stimulus placed among seven shades of grey. The hatchery-produced crabs learnt this task after 14 days of reward training, and thereafter distinguished blue in 27 non-reward trials, and green in 39 non-reward trials. The wild-captured crabs did so after 25 days of reward training, and distinguished green in 49 non-reward trials. These results indicated colour vision in S. tranquebarica. However, the crabs were unable to distinguish blue or green in dim light of 4.4 cd/m2 (which is slightly brighter than full moon light). The high colour vision threshold was attributed to the small optic parameters of the apposition compound eyes of S. tranquebarica.
    • Book

      Biology of milkfish (Chanos chanos Forsskal) 

      TU Bagarinao - 1991 - Aquaculture Department, Southeast Asian Fisheries Development Center
      An up-to-date account is given of the biology of milkfish (Chanos chanos) under the following chapter headings: Species identity and history; geographic distribution and variation; life history and habitat; food and feeding habits; age, growth and mortality; reproduction; behavior; environmental physiology; and, community relationships.
    • Book

      Code of practice for sustainable use of mangrove ecosystems for aquaculture in Southeast Asia. 

      TU Bagarinao & JH Primavera - 2005 - Aquaculture Department, Southeast Asian Fisheries Development Center
      This 47-page guidebook presents the 22 concepts, principles or policy statements that prescribe the preferred ways of doing and acting to ensure the sustainable use of mangroves for fish farming. It is annotated with definitions, explanations and many examples. Published jointly by ASEAN and SEAFDEC, this guidebook is a result of a Southeast Asian-wide consultation with core experts and country representatives in 2004 to 2005.
    • Article

      Colour discrimination in dim light by the larvae of the African catfish Clarias gariepinus 

      G Kawamura, T Bagarinao, PK Hoo, J Justin & LS Lim - Ichthyological Research, 2017 - Springer
      Many demersal fish species undergo vertical shifts in habitats during ontogeny especially after larval metamorphosis. The visual spectral sensitivity shifts with the habitat, indicating a change in colour vision. Colour vision depends on sufficient ambient light and becomes ineffective at a particular low light intensity. It is not known how fishes see colour in dim light. By means of a behavioural experiment on larval African catfish Clarias gariepinus in the laboratory, we determined colour vision and colour discrimination in dim light. Light-adapted larvae were subjected to classical conditioning to associate a reward feed with a green or a red stimulus placed among 7 shades of grey. The larvae learned this visual task after 70 and 90 trials. A different batch of larvae were trained to discriminate between green and red and then tested for the ability to discriminate between these colours, as the light intensity was reduced. The larvae learned this visual task after 110 trials in bright light and were able to discriminate colours, as light was dimmed until 0.01 lx, the minimal illuminance measurable in this study, and similar to starlight. The retinae of the larvae were found to be light adapted at 0.01 lx; thus indicating cone-based colour vision at this illuminance. For comparison, three human subjects were tested under similar conditions and showed a colour vision threshold at between 1.5 and 0.1 lx. For the larvae of C. gariepinus, the ability of colour discrimination in dim light is probably due to its retinal tapetum, which could increase the sensitivity of cones.
    • Article

      Colour preference and colour vision of the larvae of the giant freshwater prawn Macrobrachium rosenbergii 

      G Kawamura, T Bagarinao, ASK Yong, IMX Jeganathan & LS Lim - Journal of Experimental Marine Biology and Ecology, 2016 - Elsevier
      This paper reports on the innate colour preference and colour vision in the hatchery-reared larvae (10–16 days old, stages IV–VIII) of the giant freshwater prawn Macrobrachium rosenbergii (De Man) based on their response to coloured beads in a grey-walled tank under natural illumination. Plastic beads (4.1 mm in diameter) of different colours (dark blue, light blue, light green, yellow, red, white, black, and grey) in various combinations were suspended in the water 5 cm from the water surface and 12–20 cm from the tank walls where the larvae rested in the absence of aeration. The larvae swam head first straight toward the beads and gathered around them. The number of larvae was highest around the dark blue, light blue, and white beads; lowest around the black, red, and light green beads; and moderate around the yellow bead. Tests with different colours in combination with three shades of grey indicated that the larvae of M. rosenbergii discriminated colours by chromaticity. The preference for blue seemed to be an innate rather than a learned ability since the larvae did not prefer the yellow and red beads that were more similar to the colours of the egg custard and the Artemia nauplii on which they had been reared.
    • Conference paper

      The decline of native fishes and fisheries and the rise of aquaculture in lakes and rivers in the Philippines 

      T Bagarinao - In Conservation and Ecological Management of Philippine Lakes in Relation to Fisheries and Aquaculture: Proceedings … Seminar-Workshop held on October 21-23, 1997, INNOTECH, Commonwealth Ave., Diliman, Quezon City, Philippines, 2001 - Aquaculture Department, Southeast Asian Fisheries Development Center; Philippine Council for Aquatic and Marine Research and Development (PCAMRD), Department of Science and Technology; Bureau of Fisheries and Aquatic Resources
      This paper reviews historical and recent data on biodiversity, fisheries, exotic fishes, and aquaculture in Philippine lakes and rivers. The country's lakes and rivers are poor in primary freshwater fishes because the Philippines' only connection with the Asian mainland had been through land bridges between Borneo, the Sulu islands, Mindanao, Palawan and Mindoro - in which islands endemic carps have evolved. Philippine lakes and rivers instead have secondary freshwater fishes such as gobies, migratory marine fishes such as mullets, and some snails, clams, and prawns. Most lakes and rivers have been severely degraded and their biodiversity reduced by siltation, pollution, overfishing, and the establishment of exotic fishes from other countries or elsewhere in the country. Many fishes first described in the Philippines in 1910-1940 by Seale, Herre, and Filipino ichthyologists have not been collected in recent years. The Laguna de Bay fishery in the early 1960s was largely dependent on the 'ayungin' Therapon plumbeus, 'biyang puti' Glossogobius giurus, and the 'kanduli' Arius manilensis that together comprised 95% of the annual 83,000 mt; another 19,000 mt came from shrimps and 245,000 mt from snails. Fishing and snail-dredging were so intense that catches declined and the whole lake fishery collapsed around 1970. After the collapse, the primary production of the lake increased and milkfish and tilapia became natural choices for aquaculture. Lake Lanao became famous for its species flock of 18 endemic carps, but these are now extinct, except perhaps two species. In 1963, these carps contributed 981 mt to the fishery, other native fishes 269 mt, shrimps and snails 257 mt, and introduced fishes 479 mt. Twenty years later, endemic carps have made up only 92 mt, native fishes 141 mt, shrimps and snails 164 mt, and introduced fishes 312 mt of the harvest from the lake. The 'kadurog' G. giurus, probably stocked in the lake with milkfish larvae in 1955, proliferated in the 1960s and apparently drove the endemic carps to extinction. The 'katolong' Hypseleotris agilis was first seen in the lake in 1977 and has since outcompeted the 'kadurog'. In Lakes Taal and Naujan, migratory marine fishes have been caught by fish corrals set across the outlets, but the catch along Pansipit River has fallen since the turn of the century and that in Butas River fell from 62 mt in 1977 to 17 mt in 1983. Catches of the endemic sardine Harengula tawilis in Lake Taal fluctuated between 4,400 mt in 1983 to 11,300 mt in 1990 and 1,400 mt in 1994. Cage culture of tilapia and milkfish has been going on in Lake Taal for 10 years. In Lakes Buhi and Bato, the endemic 'sinarapan' Mistichthys luzonensis almost disappeared due to fine-net fishing and tilapia stocking; catches have been 50-90 mt in 1983-93 but zero in 1994.
    • Article | Short report

      Early appearance of the retinal tapetum, cones, and rods in the larvae of the African catfish Clarias gariepinus 

      G Kawamura, T Bagarinao, J Justin & CY Chen - Ichthyological Research, 2016 - Springer Verlag
      In the retina of the African catfish Clarias gariepinus, the pigment epithelium and the tapetum were formed in newly hatched larvae, the cones developed within 2 days, and the rods within 3 days after hatching. The retinal tapetum shone under surface light under a light microscope; the shine was located in the apical projections of the pigment epithelial cells. Early appearance of the retinal elements enables African catfish larvae to see and feed well even in dim light.
    • Book chapter

      Early ossification and development of the cranium and paired girdles of Chanos chanos (Teleostei, Gonorynchiformes) 

      G Arratia & T Bagarinao - In T Grande, FJ Poyato Ariza & R Diogo (Eds.), Gonorynchiformes and Ostariophysan Relationships: A Comprehensive Review, 2010 - Science Publishers
      In this chapter, we provide new data on the timing of ossification of cranial and paired girdle elements, and compare our results, when it is possible, with previous work on early ossification development of Chanos chanos. This is particularly important because of the basal phylogenetic position of Chanos among living ostariophysans and among extant gonorynchiforms as well (see Fig. 3.1). We describe the normal cranial and girdle patterns of ossification in Chanos chanos and evaluate to what extent the cranial development is consistent, or whether some intraspecific differences occur in comparison to previous results by Taki et al. (1987) and Kohno et al. (1996a) based on ontogenetic series grown in the same Aquaculture Department as the specimens used in this study. We assess previously published developmental work in a few ostariophysans and test some previous hypotheses on heretochrony and patterns of diversification. [A study of chondrification versus ossification processes in Chanos chanos is outside the scope of this paper, but it is the subject of a separate paper (Arratia and Grande, in preparation).]
    • Article

      Ecological considerations in milkfish farming in marine pens and cages in the Philippines 

      T Bagarinao - UPV Journal of Natural Sciences, 1998 - University of the Philippines in the Visayas
      Milkfish farming in the Philippines has a long history and great importance, being widely regarded as the way to domestic food security. But the industry has faced new challenges in the past decade, with the advent of many other farmed aquatic species, mostly cash crops and "export winners," and with the increased pressure to intensify production in brackishwater ponds and in marine pens and cages. There are no up-to-date government statistics on the area and production of marine pens and cages, but industry insiders estimate a yearly production of about 25,000 mt of sea-grown milkfish in 1996 - 1998, mostly from Pangasinan, but also from Quezon, Davao, Cebu, Bohol, Panay, Samar, and Negros. High yields (2 -38 kg/m3) were made possible by very high stocking rates (3 -75 fingerlings/m3) and feeding rates (2-4 kg feed per kg of fish). The high production costs and the pollution from feed wastes and fish metabolites have stopped most operations within 1 - 2 years. This paper examines the trends and problems in milkfish farming in marine pens and cages, and discusses the ecological limits and the projected ecological footprint of this farming system. Milkfish farming in marine pens and cages, as presently practised, is not the magic solution to the fish deficit in the Philippines and is not an appropriate technology to promote on a wide scale. The required investment is enormous. Properly made pens and cages set up in suitable clean-water locations cost much. The ability of milkfish to ensure domestic food security is negated by the use of fishmeal-based feeds. Fish feeds use up fish meal and other fisheries and agriculture products used by people and other sectors. If marine pens and cages must be promoted, integrated coastal area management, an informed precautionary approach, better infrastructure, and improved feeding management are important to ensure sustainability.
    • magazineArticle

      Ecological limits of high-density milkfish farming 

      T Bagarinao - SEAFDEC Asian Aquaculture, 1997 - Aquaculture Department, Southeast Asian Fisheries Development Center
      In the Philippines at present, milkfish farming in ponds includes a wide range of intensities, systems and practices. To make aquaculture possible, ecosystems are used as sources of energy and resources and as sinks for wastes. The growth of aquaculture is limited by the life-support functions of the ecosystem, and sustainability depends on matching the farming techniques with the processes and functions of the ecosystems, for example, by recycling some degraded resources. The fish farm has many interactions with the external environment. Serious environmental problems may be avoided if high-intensity farms are properly planned in the first place, at the farm level and at the level of the coastal zone where it can be integrated with other uses by other sectors. It is believed that the key to immediate success in the mass production of milkfish for local consumption and for export of value-added forms may be in semi-intensive farming at target yields of 3 tons per ha per year, double the current national average. Intensive milkfish farming will be limited by environmental, resource and market constraints. Integrated intensive farming systems are the appropriate long-term response to the triple needs of the next century: more food, more income, and more jobs for more people, all from less land, less resources, and less non-renewable energy.
    • Book

      Ecology and farming of milkfish 

      T Bagarinao - 1999 - Aquaculture Department, Southeast Asian Fisheries Development Center
      This book is a reader-friendly illustrated account of the life history of milkfish (Chanos chanos) in nature and in aquaculture. It describes the different farming systems and status of the milkfish industry, and recommends means to ensure sustainability.
    • magazineArticle

      Economic value of the milkfish industry 

      T Bagarinao - SEAFDEC Asian Aquaculture, 1998 - Aquaculture Department, Southeast Asian Fisheries Development Center
      A brief description is given of the milkfish (Chanos chanos) farming industry in the Philippines. Over the past 20 years, the relative importance of milkfish has declined with the expansion of tilapia, tiger shrimp and seaweed farming. In 1975, some 141,461 mt of milkfish made up 10% of the total fish production, whereas in 1995, the total milkfish harvest of 150,858 mt made up only 5.5% of the total fish production. Milkfish are harvested and marketed mostly fresh or chilled, whole or deboned, but some are canned or smoked. The domestic markets, mainly in Metro Manila, absorb most of the production. Milkfish is also absorbed in different product forms: dried, canned, smoked, or marinated. An export market for quick-frozen deboned milkfish fillets has begun to develop and fish processing companies are responding fast. The milkfish farming industry has important linkages with the various sectors that supply the inputs, and those that transport, store, market or process the harvest. For intensive milkfish farming to be both profitable and sustainable, more value-added products must be developed and marketed.
    • Article

      Effect of colored light regimes on the stress response and RNA/DNA ratio of juvenile red sea bream, Pagrus major 

      G Kawamura, TU Bagarinao, K Anraku & M Okamoto - Borneo Journal of Marine Science and Aquaculture, 2017 - Borneo Marine Research Institute, Universiti Malaysia Sabah
      We hypothesized that fish with red-sensitive retina would be stressed by red light and thus inhibited in somatic growth. Red sea bream (Pagrus major) juveniles (total length =3 cm) with red-sensitive retina were chosen to test this hypothesis. We examined the effect of different color lights (red with λmax 605 nm; green with λmax 540 nm; blue with λmax at 435 nm; and white with full spectrum) on unfed juveniles in laboratory tanks. Stress level was measured by the plasma cortisol and glucose concentrations, and nutritional status by muscle RNA/DNA ratio. Under red light, plasma cortisol and glucose, and muscle RNA/DNA were significantly higher than under green, blue, or white light. Our hypothesis was partly supported by previous findings on the effects of the color environment and spectral sensitivity of reared fishes. However, the levels of cortisol, glucose, and RNA/DNA in this study were low compared to published values. It seems that hatchery-bred juvenile red sea bream have adapted to red-rich surface light and are able to cope with the stress of living in surface floating cages which is so different from their deep-water habitats.
    • Conference paper

      Egg size and larval size among teleosts: implications to survival potential 

      TU Bagarinao & TE Chua - In JL Maclean, LB Dizon & LV Hosillos (Eds.), The First Asian Fisheries Forum. Proceedings of the First Asian Fisheries Forum, 26-31 May 1986, Manila, Philippines, 1986 - Asian Fisheries Society
      A survey of the early life history characteristics of 135 teleost fishes from freshwater, marine, tropical, temperate and boreal habitats show the influence of egg size and larval size on survival potential. Marine species have smaller eggs and larvae than freshwater species at similar temperatures. Coldwater species tend to have larger eggs and larvae than warm water species. Egg diameters are positively correlated with larval lengths (Lh) and weights at hatching. The times from fertilization to onset of feeding (tf), to yolk and oil resorption (ty) and to irreversible starvation (ts), increase linearly with Lh and decrease exponentially with temperature. Both tf and ts are positive linear functions of ty. Thus, larger larvae with much yolk that lasts for a relatively longer period feed later and if not fed, will starve later than small larvae with little yolk. Larger larvae will thus have the advantage under conditions of limited or variable food supply. Moreover, large larvae tend to have large mouths and are thus capable of ingesting large high-calorie prey. They also tend to have higher swimming speeds and greater potential to encounter food and avoid predators. There is no definite relation between growth rates and Lh, but tropical species with small eggs and larvae tend to have high growth rates. Survival potential has implications in the recruitment to natural stocks and in seed production in hatcheries.
    • Conference paper

      Feeding habits of larval rabbitfish, Siganus guttatus in the laboratory 

      S Hara, H Kohno, M Duray, T Bagarinao, A Gallego & Y Taki - In JL Maclean, LB Dizon & LV Hosillos (Eds.), The First Asian Fisheries Forum. Proceedings of the First Asian Fisheries Forum, 26-31 May 1986, Manila, Philippines, 1986 - Asian Fisheries Society
      The feeding habits of Siganus guttatus larvae were determined in laboratory rearing studies at 23.8-30.3 degree C by examination of digestive tract contents of larvae given rotifers and/or brine shrimp. Larvae were initially fed on rotifers at a total length (TL) of 2.6 mm (day 2 from hatching), and on brine shrimp at 4.4 mm TL (day 12). A change in feeding habits, seen as the flexion point in the relationship between larval TL and maximum amount of prey, occurred at about 7.0-9.5 mm TL with rotifers as prey, and at 7.2 mm TL with brine shrimp. Higher preference for brine shrimp over rotifers was seen in larvae 8-9 mm TL and larger. These changes in habit coincided with the full osteological development of the feeding apparatus in larvae at 7-8 mm TL. S. guttatus larvae exhibited a diurnal feeding pattern at day 9 (mean 3.7 mm TL), day 15 (5.8 mm TL) and day 21 (7.9 mm TL).
    • magazineArticle

      The filter net [tangab] fishery in Iloilo Strait, Philippines: Food and livelihood for coastal communities in the midst of waste of non-target fishery resources 

      TU Bagarinao - Fish for the People, 2008 - Secretariat, Southeast Asian Fisheries Development Center
      The Philippines is home to a mixed of blessings: an enormous marine biodiversity, a tremendous variety of fishery enterprises, and about 50 million coastal residents who mostly fish and eat fish. So many animals and so many nets in the water result in huge total catches of target fishery species, but also unfortunately of ‘trash fish’ — huge numbers of diverse marine larvae, juveniles, small adults, and unwanted species.

      'Trash fish' is a category of fisheries bycatch, which as a whole has been estimated to average about 20% worldwide, but difficult to quantify in Philippine fisheries given the large number and variety of fishers, fishing grounds, gears, species, and markets. Moreover, it is difficult to quantify the costs and benefits of a given fishery, and in particular to balance the economic benefits to the coastal communities in terms of food and livelihood versus the ecological costs of catching (killing!) untold numbers of larvae, juveniles, and small adults of innumerable species. Qualitative information is readily available, however, and this article takes as example the case of the filter net or tangab fishery in Iloilo Strait in central Philippines. A typical tangab catch from Iloilo strait is a large mixture of small sizes of low-value and non-marketable species loaded from bagnets into many wooden boxes.
    • Book chapter

      Fish behaviour and aquaculture 

      G Kawamura, TU Bagarinao & LL Seng - In S Mustafa & R Shapawi (Eds.), Aquaculture Ecosystems: Adaptability and Sustainability, 2015 - John Wiley & Sons, Ltd
      Research in the application of fundamental concepts of fish behaviour to aquaculture has intensified recently and this chapter further elucidates fish sensory systems and functions and their involvement in the success or failure of hatchery and farm operations. Most marine fishes hatch with rudimentary sense organs that are elaborated by the time of first feeding and further improved with growth; thus, hatcheries must have the appropriate food, light and water currents for proper larval development. In grow-out farms, the ambient conditions must be at optimum or tolerable levels for the fish stock and the diets must have the right sensory characteristics to stimulate efficient feeding. Stressors for fish sensory systems include crowding, turbidity, underwater noise, chemotherapeutants, extreme pH, gas supersaturation and infection. High-density farms are stressful because the fish can sense, but cannot escape from, unfavourable conditions. Monitoring fish behaviour provides early warning of stress and disease and helps avert mortality and financial losses in aquaculture.
    • Article

      Fish farming in marine pens and cages in the Philippines: appropriate technology? 

      TU Bagarinao - Aquaculture Engineering, 1998 - Society of Aquaculture Engineers of the Philippines, Inc.
      Contributed as Discussant in Technical Session 3 on Environmental Impacts of Marine Fishcage Farming, 12th Annual Meeting of the Society of Aquaculture Engineers of the Philippines, Inc. (SAEP), held at the BFAR-National Integrated Fisheries Technology Development Center (NIFTDC), Bonuan Binloc, Dagupan City, 07 November 1998.
    • Article

      Fish habitats in a small, human-impacted Sibunag mangrove creek (Guimaras, Philippines): a basis for mangrove resource enhancement 

      JBR Abrogueña, TU Bagarinao & L Chícharo - Ecohydrology & Hydrobiology, 2012 - Elsevier
      The fish assemblage of a small, open access mangrove creek highly influenced by aquaculture farms, was studied for the first time in the Philippines as a baseline of such system as well as examining the degree of ecological disturbance among fish habitats, as basis for the necessity to rehabilitate mangrove resources aiming to balance human activities and mangrove functioning. In total, 475 fishes (total weight = 3875 g) were captured and 50 species representing 32 families were identified. Thirty two species were represented by small numbers (< 5 individuals). Commercial species was considerably high (~23 species) but majority were low grade commercial species. Total species, species diversity and fish abundance consistently showed a decreasing pattern from outside creek to inner creek. Fish habitats exhibited substantial differences following a distinct spatial segregation of fish communities, a dominance of non-shared species and a minimal species overlapping inside the creek, which is attributable to the existing mangrove fragmentation associated with aquaculture ponds in the area. Increasing levels of disturbances were observed within the creek indicating ‘stress’ as a result of overutilization of mangroves by aquaculture farms. Our results confirmed the need to rehabilitate mangrove resources in this area. The development of mangrove resources through reforestation, coupled by strict regulation of fishing activities and aquaculture ponds will reduce ecological stress in the area and regain gradually a robust mangrove functioning that will improve fish diversity, fisheries and productivity of adjacent coastal systems by creating a suitable fish nursery, feeding ground and refuge habitat.