Southeast Asian Fisheries Development Center
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Grow-out culture of oyster Magallana bilineata (Röding, 1798) using pouches: A comparison of growth and survival in the river and earthen pond
No full textOysters are among the most in-demand aquaculture commodities in the Philippines and worldwide. With the decreasing culture area and the deteriorating water quality of oyster beds, there is a need to explore new culture sites and techniques to address the problems of dwindling stocks and the increasing demand for better quality oysters. This study compared the growth and survival of the oysters Magallana bilineata, the new accepted name of Crassostrea iredalei, cultured in an earthen pond and the river using pouches suspended from rafts. Mean growth rates of oysters in length and weight were significantly higher in those reared in the river (0.56 ± 0.02 cm mo-1; 10.27 ± 0.42 g mo-1) than those in the pond (0.41 ± 0.03 cm mo-1; 5.99 ± 0.22 g mo-1), but the meat yield of oysters reared in the river (25.96 ± 0.92%) was almost the same as in the pond (24.05 ± 1.41%). Likewise, the proximate composition was the same for oysters coming from the river and the pond, respectively — 58.04 ± 0.14% and 53.86 ± 0.38% crude protein, 7.00 ± 0.08% and 7.93 ± 0.38% crude fat, 24.68 ± 0.07% and 28.54 ± 0.74% nitrogen-free extract, and 10.27 ± 0.01% and 9.68 ± 0.01% ash. Oyster survival at harvest was significantly higher in the river (70.21 ± 2.84%) than in the pond (13.10 ± 1.57%). However, with some interventions, ponds may still be utilized for oyster culture despite the low survival results in this study. Extending oyster culture in these aquaculture facilities may serve as a basis for interventions to make the pond more habitable for oysters and may help boost production in the country.The authors greatly appreciate the Aquaculture Department of the Southeast Asian Fisheries Development Center (SEAFDEC/AQD) for funding the study (Project Code FS-02-M2019T)
Alternate day feeding as a cost-effective strategy for tank culture of the Pacific shortfin eel Anguilla bicolor pacifica
No full textThere is a growing interest in the aquaculture of tropical anguillid eels as an export commodity. However, studies on feeding strategies, and the present demand to reduce feed costs need to be addressed to ensure the economic viability of eel farming. In this study, the effects of daily (DF) and alternate day (ADF) feeding on growth, feed utilization, body composition, blood chemistry, liver and intestinal morphology, and economic viability in the Pacific shortfin eel Anguilla bicolor pacifica were examined. Each feeding group of 30 elvers (166.25 ± 16.23 g mean initial wt) were randomly stocked in triplicate 4 m3 outdoor concrete tanks. These were fed for 155 d with formulated eel powder diet (49.77% crude protein; 10.21% crude lipid) made into a paste. Growth and survival were not significantly different between the two feeding groups. However, feed efficiency was improved in the ADF group, with significantly higher protein efficiency ratio (0.63) than in the DF group (0.39). Feed conversion ratio (FCR) was lower in ADF (3.85) than in the DF group (6.44), resulting in a 40% reduction in total feed consumption. Biometric indices, body proximate composition, and blood chemistry were not significantly affected. Likewise, liver and intestinal morphology showed no apparent alterations between groups. Partial costs-and-returns analysis showed that ADF yielded higher net profit and profit index. These results suggest that feeding on alternate days promote compensatory growth, better feed utilization, and normal physiological condition of A. bicolor pacifica, and reduce feed cost in the rearing process. Therefore, alternate day feeding should be promoted as a sound feed management strategy in the tank culture of tropical anguillid eels.This study was supported by the Japan ASEAN Integration Fund (Br-02-Y2018B) and the Government of Japan-Trust Fund (8300-B-RD-FD0415 and 8300-B-RD-FD0120)
AQD Matters 2023 March - April
No full textIn this issue: 1) SEAFDEC/AQD kicks off 50th anniversary celebration; 2) Oil spill-affected fisher folks learn freshwater aquaculture; 3) 4 fisheries grad join SEAFDEC's pool of skilled aquaculturists; 4) SEAFDEC/AQD stocks up on kawakawa, galunggong anew; 5) Neg Occ seeks assistance from SEAFDEC to establish multi-species hatchery; 6) Community-based hatchery to boost production of giant 'ulang
Fresh chilled and fresh frozen shrimps and prawns – Product standard
No full textThis Standard applies to fresh chilled and fresh frozen raw shrimps and prawns, which may be whole, deheaded, peeled, and peeled and deveined. This document applies to shrimps and prawns of the Penaeidae, Pandalidae, Crangonidae, Palaemonidae families but not limited to the species listed in Annex A (Commercially available shrimps and prawns species in the Philippines)
SEAFDEC/AQD highlights 2021
No full textSEAFDEC/AQD highlights 2021 is SEAFDEC/AQD's annual report updating on its accomplishments and progress for the year 2021
Preliminary assessment of genetic variation in the Japanese endemic freshwater crab, Geothelphusa dehaani, based on mitochondrial DNA sequences
No full textSuppl. material 1: Maximum Likelihood tree (Download file)
Suppl. material 2: Matrix of pairwise differences of FST (Download file)Geothelphusa dehaani, a freshwater crab species endemic to Japan, has the largest distribution range amongst the 19 known species in the country. Due to its low dispersal capability and restricted habitat to freshwater, it serves as an excellent model for understanding gene flow between geographically isolated populations. In this study, we analysed the genetic relationships of 26 G. dehaani populations collected from different locations in the Japanese archipelago using two mitochondrial DNA regions - cytochrome oxidase subunit I (COI) and cytochrome b (cytB). Our results from the analysis of molecular variance (AMOVA) revealed high genetic variation amongst populations and the phylogenetic analysis identified four geographical groups: Clade I - Honshu and Shikoku, Clade II - north-eastern Kyushu, Clade III - southern Kyushu and Clade IV - north-western Kyushu. Notably, Clade IV exhibited the highest genetic distance amongst the observed groupings. These findings highlight the need for further examination of G. dehaani in Kyushu, including morphological and behavioural traits, to better understand the observed diversity within the species in the region.This research received support from research grants (KAKENHI-Grant Number JP21H05181) and the Ministry of Land, Infrastructure, Transport and Tourism of Japan
Boosting the sustainability of aquaculture feed for the lucrative business of mangrove crab grow-out culture
No full textConventional feeds for mangrove crab (Scylla serrata) are highly fixated on the use of fish-by-products (FBC) and other slaughter wastes. These feeds, however, are highly polluting that can easily cause water quality spoilage, and may affect the health of the mangrove crab. They can likewise bring about problems in supply shortage, reliability in quality, and as carriers of disease agents.
In order to support the sustainability of the mangrove crab industry in Southeast Asia, there is a need to produce an efficient and viable aquaculture feed for this species. Although SEAFDEC has started venturing into researches with emphasis on crab feed development, it was deemed necessary to work on further improvement of feed formulation with the inclusion of ingredients that are less expensive based on published nutritional requirements and physical properties of mangrove crab.
This study assessed the efficiency of the refined crab feed in land-based tanks. Refinement of this feed formulation focused on partial replacement of fishmeal with alternative ingredients such as mussel meat meal. Cholesterol was added to refined crab feed to improve molting processes affecting the growth of the animal (Coloso et al., 2017). The same diet was evaluated for its proximate composition, water stability, amino acid and fatty acid compositions, digestibility of nutrients, attractability and palatability, and its biological effects on cultured mangrove crabs. Overall, results indicated that refined crab feed can potentially be used as sole feed for the grow-out culture of crabs as it can enhance the animals’ growth and survival in tanks
Characterization of wild eucheumatoids from Visayas, Philippines as inferred from the mitochondrial cox2-3 spacer sequence
No full textEucheumatoids are the major seaweed species cultivated in most coastal areas in the Philippines, being a major source of income for many families. Seaweed farmers face issues such as lack of good quality cultivars and the presence of diseases and epiphytes in the cultivated stocks. This study characterizes the wild eucheumatoids, which are potential sources of cultivars that might be resistant to diseases and epiphytes. Wild eucheumatoids were collected from Iloilo (N=18), Guimaras (N=10), and Bohol (N=20), Philippines. Gross morphology was described, and a 10-mm apical tip was excised for DNA extraction. PCR amplification and sequencing using cox2-3 spacer genetic markers were done. Based on sequence data, 5 species can be identified from the Visayas region: the commercially cultivated Kappaphycus alvarezii (Iloilo, Bohol), K. striatus (Iloilo, Guimaras), and Eucheuma denticulatum (Iloilo, Bohol) and the currently uncultivated K. cottonii (Iloilo) and Kappaphycus sp. (Iloilo, Bohol). Haplotype network analysis identifies individuals of K alvarezii and E. denticulatum as haplotype E3 and E13, respectively, which are haplotypes previously reported from seaweed farms and globally distributed for cultivation purposes. The K. striatus from Iloilo and Guimaras are identified as haplotype E89, and the K. cottonii from Iloilo is haplotype E108 which has been described previously from seaweed farms and wild populations, respectively. Interestingly, Kappaphycus sp. from Iloilo and Bohol are identified as haplotype GUI1 initially described in 2014 and yet to be identified up to the species level. Our study shows that purely morphological identification is not sufficient to reliably identify species, thus highlighting the need to employ molecular techniques supporting strain selection. In summary, it reveals a rich diversity of wild eucheumatoids in the Visayas region of the Philippines. In-vitro studies need to reveal the performance of individuals from these wild populations but highlight a great potential for the development of new cultivars.The authors would like to acknowledge the United Kingdom Research and Innovation and Global Challenges Research Fund for the funding, as well as their UK partners, namely, the Scottish Association for Marine Science, the Natural History Museum, the Centre for Environment, Fisheries and Aquaculture Science and the Overseas Development Institute. The authors also thank their partners from the United Nations University in Belgium, the University of Malaya in Malaysia, the University of Dar es Salaam in Tanzania, and the Southeast Asian Fisheries Development Center Aquaculture Department for their contributions during the implementation of this study
Small-scale IMTA of milkfish in pens: The Pandaraonan, Guimaras, Philippines experience
Get PDFThis study examines IMTA as an option for small-scale fish farmers to grow multiple species in the same area in the coastal waters of Barangay Pandaraonan in Nueva Valencia, Guimaras, Philippines. The study aimed to explore the feasibility of an economically profitable IMTA system where milkfish are grown with sandfish and seaweeds
Enhancing the reproductive performance of cultured shrimp: novel information on scent, maturation, and mating
No full textWhat are sex pheromones and how do they function in the courtship and mating of shrimps and other crustaceans? Best known as chemical compounds excreted by animals to initiate reproduction-related responses from their potential mates, pheromones became an important factor in shrimp culture. An earlier study, showed that the domesticated shrimp had a reduced level of pursuit behavior than the wild-caught and suggested that sex pheromones could have played a role in this behavioral difference. Domesticated penaeids are typically reared communally until ready for use as broodstock wherein animals are continually exposed to varying chemical cues. There is a close relationship between chemicals involved in molting and mating of closed thelycum species but information regarding the effect of prolonged exposure of male penaeids to molting and sex pheromones of females on reproduction behavior is not available.
In 2021, SEAFDEC/AQD conducted a research to evaluate the possible implications of monosex rearing on gonad maturation and reproduction behavior of Penaeus indicus broodstock. Results demonstrated that the traditional communal rearing of male and female P. indicus broodstock do not have a significant effect on the ovary development and sperm quality of female and male broodstock, respectively. But this common practice of rearing male and female broodstock together significantly reduced reproductive related behavior leading to lower successful matings compared to when broodstock were reared monosex. This novel information could be linked to previous report on reduced successful matings previously reported in black tiger prawn, P. monodon. Therefore, monosex rearing should be considered as an alternate broodstock setup as this will facilitate optimized sexspecific nutritional manipulation and even potentially increase the mating success of domesticated penaeid broodstock