Pawikan on FB: Facebook as a Source of Information on the Current State of Sea Turtles in the Philippines with an Emphasis on Mortality

Five of the seven species of pawikan (sea turtles) are found in the Philippine seas. These are Olive ridley turtle (Lepidochelys olivacea), Hawksbill turtle (Eretmochelys imbricata), Green sea (Chelonia mydas), Loggerhead turtle (Caretta caretta), and Leatherback turtle (Dermochelys coriacea). All of these are threatened species due to predation (animals and humans), climate change, harvesting of eggs, juveniles and adults, bycatch, and habitat degradation. Thus, to protect the species, several laws, policies, and programs have been passed and implemented by the Philippines government since 1979 (Marine Wild Fauna Watch of the Philippines (MWFWP), 2014). However, despite the efforts to protect the pawikan, reports about dead sea turtles due to various causes are becoming frequent than ever. Furthermore, public posts on Facebook about dead pawikan by private individuals are increasing. On the other hand, data on the mortality causes of sea turtles remain scarce as of the moment. Hence, to provide additional data, this study was conducted

The influence of monosex rearing on gonad maturation and reproductive behavior of Indian white prawn, Penaeus indicus broodstock

Monosex culture was proven to be an effective rearing method for grow-out, but in a closed-cycle hatchery, males and females are usually reared communally in tanks until maturation. This study determined the effect of communal rearing (CR) and separate rearing (SR) on male and female Penaeus indicus broodstock gonad maturation. This study also evaluated the influence of the rearing method on reproductive behavior and mating success. The results showed that CR female broodstock had higher maturation rates at 77.78 ± 5.31% (p = 0.061) and a shorter latency period at 6.71 ± 2.54% than SR females (p = 0.211), but the differences were not statistically significant. Similarly, maturation rates for both male groups were 40.62 ± 3.12% and were not significantly different (p = 1.00). The interspermatophore period (p = 0.044), spermatophore weight (p = 0.878), count (p = 0.780), viability (p = 0.257), and percent abnormality (p = 0.257) did not vary between males. In terms of the effect of rearing method on reproductive behavior, males from the SR group initiated more chase (p = 0.018) and fight with other males (p = 0.022) than CR males did, and the differences were significant. SR males also touched the discarded molt (p = 0.167) and advanced to the probe position (p = 0.525) more times than CR males, but the differences were not significant. The sum of all the reproductive behaviors was also significantly higher in the SR (54.00 ± 1.20) than in the CR (24.20 ± 0.86) groups (p = 0.017). Initial results showed that successful mating in the SR (80%) was higher than that recorded in the CR group (20%). These findings suggest that monosex rearing of male and female P. indicus will not negatively affect gonad maturation and will enable sex-specific nutritional manipulations, which can even possibly promote higher mating success.This study was funded by the Department of Science and Technology-Accelerated Science and Technology Human Resource Development Program, Student Research Support Fund and SEAFDEC/AQD (FD-02-C0219T)

Vibrio harveyi-like bacteria associated with fin rot in farmed milkfish Chanos chanos (Forsskal) fingerlings in the Philippines

Milkfish (Chanos chanos) is a commercially important species widely cultured and consumed in the Philippines. It is a hardy fish but due to culture intensification, occurrence of bacterial disease is inevitable. The causative agent of fin rot disease in milkfish fingerlings (total length [TL] = 2.8–4.5 cm) reared in intensive nursery earthen ponds in the Philippines was investigated in the current study. Following biochemical characterization tests and 16S rRNA sequencing, seven isolates recovered from affected fish were identified as Vibrio harveyi-like bacteria. Immersion challenge of milkfish (TL = 5.64 ± 0.76 cm) using a representative strain (CCL-01) at inoculum dose of 108 CFU/mL resulted in fin rot as early as 1-day post-infection (dpi) and concomitant mortalities of 57% ± 0.58 at 7 dpi. Moreover, when milkfish (TL = 6.18 ± 0.66 cm) stocked at 5, 10, and 20 fish/5 L were exposed to the computed 168-h lethal dose (LD50) at 6.63 × 104 CFU/mL, significant mean mortality of 45% ± 1.0 coupled with typical signs of fin rot were particularly obtained in fish stocked at 20 fish/5 L (biomass = 4 g/L) while low mortality of 0% and 7% ± 0.58 were recorded in fish stocked at 5 fish/5 L and 10 fish/5 L, respectively, at 7 dpi. Vibrio harveyi-like bacteria was reisolated in lesions and kidney of all challenged fish while none in any of the control fish. The current data clearly indicate that the isolated V. harveyi-like bacteria is an opportunistic pathogen capable of instigating disease epizootics in milkfish fingerlings stocked at higher densities.This study was funded by the Department of Science and Technology through the Philippine Council for Agriculture, Aquatic and Natural Resources Research and Development (PCAARRD) under the UPV-DOST Milkfish Program A. Also, Oversea Feeds Corporation, SEAFDEC Aquaculture Department and Dr. Carlo Lazado are greatly acknowledged for the milkfish samples, use of the research facilities and valuable inputs in editing an earlier draft of the paper, respectively

Pawikan on FB: Facebook as a Source of Information on the Current State of Sea Turtles in the Philippines with an Emphasis on Mortality

Sea turtles or “pawikan” are threatened and protected species in the Philippines. In fact, since 1979, the Philippine government has enacted several laws and policies and implemented programs for the conservation of the five of the seven species of sea turtles that could be found in the Philippines. However, reports on poaching, egg collecting, stranding, by-catch, and even slaughtering of sea turtles become more evident than ever, especially on social media (SM) despite these efforts. SM has proven to be one of the most effective platforms for information sharing as anyone who has an account, and an internet connection could easily share information. This study will present data on the threats facing sea turtles in the Philippines by analyzing Facebook (FB) posts of organizations, communities, and individuals about sea turtles from 2008-2019. Only posts that contain visual evidence such as photos and/or videos will be considered. Information on the species, location, and status of the sea turtles will be provided. Moreover, the mortality causes for dead specimens will also be presented. Furthermore, to determine the awareness of the public on the status of sea turtles as threatened and protected species, sentiment analysis will be done to the reactions, comments, and opinions on every post that will be considered in the study.2020-02-1

Growth performance, production and economic viability of Indian white shrimp (Penaeus indicus H. Milne Edwards) fed with varying dietary protein levels

The growth efficiency, productivity and economic viability of Indian white shrimp (Penaeus indicus) fed with diet containing 40% (CPhigh) and 34% (CPlow) crude protein (CP) levels were determined in a 90-day grow-out culture trial. Growth parameters including average body weight (ABW), specific growth rate (SGR), survival and feed conversion ratio (FCR) were not statistically different. CPlow had lower overall shrimp production (797.53 kg/ha, DOC 90), but was not significantly different from CPhigh (843.78 kg/ha, DOC 90). The mean values for the water parameters of both treatments, such as DO, pH, salinity, temperature, TAN, NO2-N, NO3-N and PO4-P, also showed no significant differences. However, the TAN values of CPhigh were consistently higher from day of culture (DOC) 63 and increased significantly (p = .048) at DOC 90. Furthermore, the total bacterial and Vibrio counts in both treatments were not significant throughout the culture period. The economic analysis revealed that CPlow obtained higher net profits (6093 USD/ha/year), return on investment (72%) and discounted benefit–cost ratio (1.73). The current study found that feeding a low protein diet to P. indicus is economically viable and profitable and results in improved growth efficiency and productivity while also improving water quality and lowering nitrogen discharge.This study was supported by Aquaculture Department, Southeast Asian Fisheries Development Center (DP-02-C2017T)

Inclusion of live mud polychaete (Marphysa iloiloensis) in the feeding regime improved the hatchery performance of domesticated Indian white shrimp (Penaeus indicus)

A 60-day feeding trial was conducted to evaluate the effect of inclusion frequency of hatchery-bred mud polychaete, Marphysa iloiloensis, as part of a combination diet on the reproductive performance and larval quality of domesticated P. indicus. The two treatments were fed with a combination of formulated diet, mussel, squid, and mud polychaete with once (T1) and twice (T2) a week inclusion in the feeding regime. In contrast, the control group was fed only a diet combination of mussels, squid, and formulated diet. There was no significant difference in the mean survival of male and female broodstock in all treatments upon termination ($p\gt0.05)$. Shrimp in T1 and T2 performed significantly better than the control in terms of spawning frequency ($p=0.037)$ and fertilization rate ($p=0.001)$, while T1 had significantly high re-maturation ($p=0.038)$. The survival, spawning, hatching rate, egg, and nauplii production did not differ significantly among treatments ($p\gt0.05)$. Also, no difference in the gonado-somatic index (GSI), hepato-somatic index (HSI), spermatophore weight, and sperm count was found among diet treatments ($p\gt0.05)$. Post larvae from T1 and T2 performed significantly better than the control after 25 ($p=0.008)$ and 30 ($p=0.009)$ minutes of abrupt exposure to freshwater, respectively. Therefore, even once weekly, mud polychaete inclusion is sufficient to improve the reproductive performance of P. indicus broodstock and produce offspring with boosted resistance in the hatchery.This study was supported by SEAFDEC/AQD (Study Code: DP-02-C2017T)

Reproductive quality evaluation of male Indian white prawn Penaeus indicus broodstock-fed diets supplemented with polychaete extracts (Marphysa sp.)

The present study determined the effect of different polychaete extracts, namely, total soluble fraction (TSF), neutral lipid fraction (NLF) and polar lipid fraction (PLF), in the maturation and sperm quality of male Penaeus indicus. Three levels (0.25, 0.50 and 1.00%) of extracts were included using a 3 × 3 factorial design. Groups fed the basal diet (BD) and fresh-frozen diet served as controls. Extracts in varying doses and control groups did not have a significant effect on broodstock survival (67–87%; p = 0.960), maturation rate (42–68%; p = 0.615), inter-spermatophore period (8–10 days; p = 0.505) or sperm viability (97–100%; p = 0.819). However, sperm counts of broodstock fed BD (11.70 × 106 ±1.05 × 106 per spermatophore) and those fed diets supplemented with polychaete extracts were significantly higher compared to that fed with control fresh diet at 0.73 × 106± .09 × 106 (p = 0.001). Spermatophore crude lipid was highest in groups fed 0.25% TSF and 0.25% PLF of broodstock (p =1.0 x10−6 ). Inclusion of TSF (0.25–1.00%) significantly increased the spermatophore crude protein content of broodstock compared to those fed with other diets (p = 1.20 × 10−5). These results demonstrate that NLF and TSF extracts are bioactive components of polychaete which when fed to male P. indicus, can stimulate aspects of sperm production