Southeast Asian Fisheries Development Center
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AQD Matters 2024 March - April
No full textIn this issue: 1) SEAFDEC builds up stock of tuna breeders to enhance research efforts; 2) SEAFDEC/AQD attends 33rd NACA meeting; 3) SEAFDEC officials pay courtesy visit to DA-BFAR; 4) SEAFDEC fish health management training attended by 5 member countries; 5) Progress of Japan-funded SEAFDEC/AQD programs reviewed; 6) SEAFDEC/AQD, BFAR, LGUs unite: Marine fish hatchery operations training organized for BFAR, LGU staff; 7) Sea cucumber hatchery technicians upskilled to solve a production bottleneck; 8) SEAFDEC/AQD info staff serve as resouce persons in inter-departmental workshop; 9) Experts from SEAFDEC/AQD share insights on marine aquaculture; 10) University of Massachusetts Lowell professors tour SEAFDEC/AQD; 11) Igang Marine Station harvest ields pompano, milkfish; 12) Rescued sea turtle back into the wild after eight months; 13) The benefit of intermittent fasting – for eels; 14) Davao rep donates P1 million to FishWorld Museu
Population genetic variation and genetic structure of widely distributed Japanese endemic freshwater crustaceans: Geothelphusa dehaani and Gammarus nipponensis
No full textFreshwater crustaceans, Geothelphusa dehaani (White 1847) and Gammarus nipponensis (Ueno 1940), are commonly found in rivers, streams and lakes in Japan. The distribution range of G. nipponensis is concentrated in the Western portion of Japan while G. dehaani exhibits a more widespread distribution. Both species undergo direct development from eggs to juveniles and have limited migratory abilities, as they are intolerant to brackish and marine environments. This restricted dispersal capability leads to geographical isolation among populations, making these freshwater crustaceans as ideal models for studying gene flow. Despite their significance, there were scarcity of studies that clarified genetic patterns in these two widely distributed crustaceans. Thus, the objectives of this thesis were to conduct genetic assessments on both G. dehaani and G. nipponensis to understand their population structure and variation, and to provide insights into past geological events that have contributed to these variations. Here, mitochondrial DNA sequence data were utilized to infer the relationships between the local populations of these species.
Results of this study revealed substantial genetic variations among populations in both crustaceans. In G. dehaani, distinct haplotypes were observed in most populations, while G. nipponensis exhibited remarkably high mitogenome sequence variability across different localities. These findings implied extremely limited gene flow within each population and a reduced capacity for migration over extended periods, a characteristic that distinguishes them from other strictly freshwater species. The time to most recent common ancestor (TMRCA) estimates proposed that the ancestor lineage of G. dehaani was introduced more recently in Japan, approximately around the Pleistocene (~1 million years ago), while that of G. nipponensis predates the separation of Japan from mainland Asia around late Oligocene (~24 million years ago). Despite these differences, the structural patterns of populations in both species appeared relatively similar.
Based on the phylogenetic analysis, the populations in both species are considered highly monophyletic with several geographical groups detected. In G. dehaani, four distinct geographic groups formed: Clade I (Honshu and Shikoku), Clade II (Eastern Kyushu), Clade III (Southern Kyushu and a portion of Eastern Honshu) and Clade IV (Western Kyushu). In G. nipponensis, the three identified groups were Clade I (Honshu and Shikoku), Clade II (Eastern Kyushu) and Clade III (Western Kyushu). The geological boundaries separating these major clades consisted of ancient lowlands such as the present Seto Inland Sea and the Chikushi and Fukuoka plains, acting as barriers for gene flow. The Seto Inland Sea potentially contributes to the divergence of Clade I from the Kyushu group. Despite the Seto Inland Sea acting as a barrier, Honshu and Shikoku displayed closer genetic relationships, possibly attributed to their more recent separation. Likewise, the Chikushi and Fukuoka plains was a significant barrier, defining distinct genetic groups in Kyushu.
In conclusion, this study emphasized the importance of these two freshwater crustaceans in understanding genetic relationships characterized with limited gene flow and the impact of geological events on their population dynamics in the Japanese Archipelago. The need for further examination of morphological and behavioral characteristics based on the genetically detected groups of G. dehaani and G. nipponensis is suggested
Effect of stocking density on growth, biochemical composition and blood parameters in the Pacific shortfin eel Anguilla bicolor pacifica elvers
No full textThis study examined the effect of stocking density on growth, biochemical composition, and blood parameters of the Pacific shortfin eel Anguilla bicolor pacifica. Elvers (1.95 ± 0.14 g body weight) were randomly stocked in indoor tanks and reared over 186 d at three stocking densities (0.3, 0.6, and 0.9 kg m-3) set up in triplicates. Except for survival and biometric indices, elvers maintained at 0.3 and 0.6 kg m-3 densities exhibited higher growth and feed utilization than those held at 0.9 kg m-3. Yield increased with stocking density, which were significantly higher at 0.6 and 0.9 kg m-3. RNA/DNA ratio did not reflect growth rate, but trends in survival and RNA/DNA ratio with stocking density were positively related. In contrast to body proximate composition, increasing stocking density resulted in significantly higher erucic acid (22:1n-9) and total saturated fatty acid levels at 0.6 and 0.9 kg m-3 densities, respectively. Serum glutamic pyruvic transaminase activity was significantly elevated at 0.6 kg m-3, while total protein, glucose, and triglycerides slightly decreased with increasing stocking density. Results suggest that Pacific shortfin eel elvers can be reared in indoor tanks at a stocking density of 0.3 – 0.6 kg m-3 to achieve acceptable growth, feed performance, and health condition.This work was supported by grants from the Japan ASEAN Integration Fund (Br-02-Y2018B) and the Government of Japan-Trust Fund (8300-B-RD-FD0415 and 8300-B-RD-FD0120). The authors thank Mr. Nemencio Olorvida and the entire staff of SEAFDEC/AQD Binangonan Freshwater Station for the laboratory assistance
Field evaluation of hydrogen peroxide bath technique for controlling sea lice (Lepeoptheirus spinifer) infestation in snubnose pompano (Trachinotus blochii)
No full textSea lice infestations can pose significant challenges in the aquaculture sector, affecting fish health and overall production. In the search for effective and eco-friendly solutions, hydrogen peroxide bath treatment has been considered as one of the promising methods. This is the first study to evaluate the field efficacy of hydrogen peroxide bath technique against sea lice infestation on cage-cultured snubnose pompano (Trachinotus blochii). Sea lice was identified as Lepeophtheirus spinifer using morphological description. Naturally-infested snubnose pompano stocked in 2 × 3 × 2 m3 net cages at 15 fish/cage at the Igang Marine Station of SEAFDEC/AQD, in Guimaras, Philippines were treated in triplicates with two hydrogen peroxide concentrations (1500 and 2000 ppm) in comparison to a control (seawater only) for 20 minutes at 32.8 ± 0.7 ppt and 28.9 ± 0.3 °C and were monitored at 3rd and 7th day post-treatment. The total mean intensity of sea lice, mean intensity per life stages (copepodid, chalimus I, chalimus II, pre-adult I, pre-adult II, adult male and adult female), and the 12-h viability of scraped male and adult female L. spinifer from the treatment groups were evaluated. The total mean intensity of sea lice in the treated groups at 3 day post-treatment was significantly lower than the control group (p < 0.001). A possible re-infection of sea lice was observed 7 days post-treatment as explained by the slight increase in the mean intensity in the treated groups. However, no mortalities of pompano were recorded throughout the experiment. In addition, adult female lice were absent in the treated group while adult male lice were only detected in the 1500 ppm treatment group at a very low mean intensity. The viability test also showed that all sea lice were not able to recover after 12 h whereas a 100 % recovery rate was noted in the control group. Results suggest that the 1500 and 2000 ppm hydrogen peroxide concentrations are effective in reducing sea lice infestation on cage-cultured snubnose pompano. However, a long-term effect of hydrogen peroxide treatment on sea lice needs further investigation.The authors thank the Technology Verification and Extension Division (Study Code: TV-08-F2021I) of SEAFDEC/AQD for funding this study
Breeding, seed production, and culture of African catfish Clarias gariepinus
Get PDFThis manual summarizes the existing techniques on the induced breeding, seed production, and culture of the African catfish based on surveys done in Iloilo, Philippines. SEAFDEC Aquaculture Department will present a standardized way of breeding and culturing the African catfish under captive conditions, but will not encourage growing them in natural freshwater habitats. Previous data have shown that their presence in lakes adversely affects the population of other indigenous species and may lead to a loss of biodiversity
Black tiger shrimp (Penaeus monodon) hatchery operations using enhanced biosecurity measures
No full textThis manual, titled “Black Tiger Shrimp (Penaeus monodon) Hatchery Operations Using Enhanced Biosecurity Measures,” includes modifications on shrimp hatchery operations done by the Aquaculture Department of the Southeast Asian Fisheries Development Center to provide high- quality postlarvae for shrimp farming. Discussed also in this manual are the necessary protocols and biosecurity measures that shrimp hatchery operators can use as their guide.
Main sections included in this manual: 1. Site Selection, 2. Biology, 3. Hatchery Layout, 4. Facilities and Equipment, 5. Biosecurity Standard Operating Procedures, 6. Hatchery Operations, 7. Diseases of Shrimps, and 8. Economic Analysis
Pag-aalaga at pagpaparami ng likas na pagkain para sa similya ng mga isda at hipong tabang
No full textInilalarawan sa manwal na ito ang iba’t-ibang paraan ng pag-aalaga at pagpaparami ng microalgae at iba pang natural na organismong pagkain para sa mga similya ng isda at hipong tabang na inaalagaan at pinaparami sa mga hatcheries. Sa pamamagitan ng manwal na ito, maisusulong ang paggamit ng mga natural at naproseso na mga nasabing organismo bilang isang paraan para mapabuti ang produksyon ng mga isda at hipong tabang.
Ang manwal na ito ay sadyang isinulat para makatulong sa mga lokal na may-ari ng mga hatcheries ng ulang at isdang tabang kabilang na ang kanilang mga technicians. Ito ay naglalayong magkaroon sila ng mas mahusay na pag-unawa sa kahalagahan ng pagpaparami at pag-aalaga ng ng mga likas na pagkain bilang isang kritikal na aspeto sa pag-aalaga at masaganang produksyon ng mga similya sa hatchery.Filipin
Undervalued, understaffed, underdeveloped, and underutilized? The status of public libraries in the eleven municipalities of rural Iloilo Province, Philippines
No full textLibraries, as service-oriented organizations, are being guided on every aspect of their operation by local and international standards. In the Philippines, public libraries are expected to adhere to the stipulations of the Philippine Standards for Public Libraries. This study was conducted to assess the adherence of the 11 municipal libraries in Iloilo Province to the following areas of the Standards: library administration, collection management, services and utilization, physical facilities, financial resources, and linkages, networking and collaboration. Findings revealed that most libraries were non-compliant with almost all aspects of the Standards. Specifically, the majority lacked support from their local government units and were managed by non-professional librarians with inadequate knowledge and skills in successfully managing a library. Additionally, most libraries have a low budget to purchase updated resources of various types and formats and appropriate facilities and equipment. Furthermore, almost all libraries lacked networks and linkages, and collaborative activities that could have helped librarians enhance their skills, improve library resources and services, and increase their visibility and value to the stakeholders. Consequently, most municipal libraries could not fulfill the community's information needs; therefore, they remained undervalued and underutilized
AQD Matters 2023 September - October
No full textIn this issue: 1) Regional Training Course on Advanced Aquaculture Technologies a success; 2) SEAFDEC Secretary-General explores AQD stations in Iloilo, Guimaras; 3) SEAFDEC/AQD readies future tiger shrimp breeders as 'Oplan Balik Sugpo' pushes on; 4) SEAFDEC/AQD joins Iloilo Farmers' and Fisherfolks' Week celebration; 5) SEAFDEC/AQD connects with stakeholders during international trade exhibit; 6) Developments in tiger shrimp, crustacean research showcased in conference; 7) Research collab on whiteleg shrimp nets 4.2 tons; 8) Deputy Chief Ito shares successful case studies at international conference; 9) SEAFDEC/AQD joins consortium for enhanced science collaboration in Western Visayas; 10) Project reviewed, plans for 2024 unveiled; 11) Scientist shares research on cost-efficient feeds during fisheries convention; 12) Free eye examination for staff, dependents; 13) Information staff discuss strategies to improve information dissemination; 14) Scientist investigates how male shrimp get fertility boost from worms; 15) Garlic extract to treat fish infections? A research team first assesses the effects of garlic on tilapia; 16) How to prevent shrimp diseases with hydrated lim