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A massive oil spill occurred near the shores of Guimaras Island, Philippines, in 11 Aug 2006 caused by the sunken MT Solar I vessel. The oil spill spread to neighboring towns of Guimaras damaging the marine coastal environment, consequently, causing health and economic problems, particularly, by affecting local fisheries, wildlife, and tourism. Hence, this study was conducted to assess, quantify, and isolate indigenous bacteria with potential petroleum hydrocarbon-degrading properties that could be used for bioremediation of oil spill contaminated areas in Guimaras and nearby provinces. Sampling were conducted in Oct and Nov 2006 to assess the level of both heterotrophic and hydrocarbon-degrading bacteria (HDB) from areas affected ( Tando, Taklong, Cabalagnan, Panobolon, Alegria, Sabang , Inampulugan) and unaffected (Lawi and Getulio) by the oil spill. Samples consisted of beach water and beach sand, mangrove surface soil and subsurface soil where levels of heterotrophic bacteria consisted of Total Aerobic Counts (TBC). Presumptive Vibrio Counts (PVC), Presumptive Aeromonas Counts (PAC) and Presumptive Pseudomonas counts (PPC) were determined. Likewise, the levels of hydrocarbon-degrading bacteria were also assessed. Results showed that heterotrophic bacteria were found in variable densities among the sampled sites with Nov soil and water samples, yielding higher counts than in Oct. The Significantly sample high density of total culturable bacteria yielded mean counts of 6.4 x 10 ⁵ cfu/g from Taklong beach soil , 5.1 x 10⁵ cfu/g from Alegria mangrove surface soil and 5.6 x 10⁵ cfu/g from mangrove subsurface soil samples of Inampulugan in Nov 2006. The levels of Vibrio were highest in Getulio at 3.3 x 10⁴ cfu/g and 2.4×10⁴ cfu/g for beach and mangrove surface soil, respectively and in Sabang for mangrove sub-surface soil at 1.6 x10⁴ cfu/g. The levels of Aeromonas were significantly highest in Alegria at 2.1 x 10⁵ cfu/g for beach soil and in Getulio at 1.5 x10⁵ cfu/g and 1.4 x 10⁵ cfu/g for mangrove surface and sub-surface soil, respectively. The levels of Pseudomonas were significantly highest in Sabang for Mangrove surface soil at 2.3 x 10⁴ cfu/g and in Cabalagnan at 1.4 x 10⁵ cfu/g and 4.5 x 10⁴ cfu/g for beach and mangrove sub-surface soil, respectively. Oil-degrading bacteria were also found in variable densities among the sampled sites including one of the oil spill unaffected sites but of low level. Although, some sites have relatively low levels and even some sites had undetectable level (<2.3 MPN/g or ml), Taklong beach soil yielded a significantly high level of hydrocarbon-degrading bacteria at 620 MPN/g. Thus, this study confirms the presence of petroleum hydrocarbon-degrading bacteria in some affected areas in Guimaras.

About one month after the M/T Solar I oil spill in Southern Guimaras, surface sediment and water samples were collected to assess the extent of petroleum contamination. Among the contaminated shoreline and mangrove areas, Guiwanon and Taklong shore and Dungkaan mangrove have the highest level of Hexane Extractable Materials (HEM) and Polycyclic Aromatic Hydrocarbon (PAH) compounds relative to the unpolluted sediment sample from Igang, Guimaras and Tubbataha, Palawan. The extent of oil contamination in the intertidal zone of Taklong shore at low tide was 18 meters landward from the water and the highest level of HEM and PAH were observed in samples collected at the interface of the warer and the shore. However, BTEX (benzene, toluene, ethylbenzene and meta, ortho, para xylenes) in water and sediment samples collected 1 month after the oil spill are below minimum risk level, MRL (2ppm). This observation could be attributed to the higher rate of volatilization of most monoaromatic hydrocarbon (BTEX) with low flash points.

To evaluate the impact on biota of the release of ~2 million liters of bunker oil off Guimaras Island, central Philippines, the penaeid shrimp populations in a protected island mangrove (Tandog) and a riverine mangrove (Sibunag) were surveyed by pocket seine 2-3 months after the August 2006 spill; results are compared to 1993 baseline data. A total of 529 individuals belonging to three penaeid species were collected – Metapenaeus anchistus in Tandog, and M. ensis and Penaeus merguiensis in Sibunag. Shrimp densities were significantly higher In Tandog Island in 2006 compared to 1993 but remained similar in the riverine mangrove. This suggests that protection may have a greater impact than the Oil Spill per se because Tandog is part of the protected Taklong National marine Reserve. In contrast to abundance, shrimp sizes (carapace length) were significantly smaller in 2006 comparted to 1993 for both sites.

Crude tissue proteins were extracted from the underutilized marine bivalves: Placuna placenta, Placuna ephippium, Scapharca inaequivalvis, and Marcia hiantina by aqueous and acidic extraction methods. Partial purification of the crude extracts was done through ammonium sulfate precipitation followed by membrane dialysis. The resulting filtrate was then subjected to centrifugal ultrafiltration to produce fractions of 10-20 kDa molecular weight. Highest total soluble proteins were observed in M. hiantina extracts at 16.20 mg/ml for hot water extraction (HWE), 11.13 mg/ml for cold water extraction (CWE), and 11.68 mg/ml for acetic acid extraction (AAE) (P<0.05). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) bands indicate low molecular weight peptides (<14 kDa) were present in HWE and AAE extracts of P. placenta and CWE of S. inaequivalvis. Highest 2, 2-diphenyl-1-picrylhydrazyl (DPPH) antioxidant activity was observed in M. hiantina CWE at 54.09 % (P < 0.05). Highest antibacterial activity against Bacillus cereus was observed in AAE and HWE extracts of P. placenta, with minimum inhibitory concentration (MIC) of 124.34 μg/ml and 195.71 μg/ml, respectively. Results of this study indicate that the protein extracts of these underutilized marine bivalves may have promising antioxidant and antibacterial activities which can be potential sources of bioactive compounds. It also confirmed the potential of using aqueous extraction to liberate the peptides, which is a more costeffective alternative to chemical and enzymatic hydrolysis.

Parasites are ubiquitous, infecting a diverse range of hosts including commercially important species. Despite being commercially exploited, very few literatures on fish parasitism are published in the Philippines. This study is one of the few conducted in a major fishing ground in the country that aims to survey the prevalence and diversity of helminth parasites in fishes caught in the municipal waters of Orani, Bataan and Sta. Cruz, Pampanga, Manila Bay. Fish samples from family Leiognathidae (n=86, 2 species), Mullidae (n=9, 3 species), Nemipteridae (n=13, 2 species), and Terapontidae (n=42, 2 species) were collected for dissection. The isolated gastrointestinal tract of collected fish samples were then examined for parasites using a dissecting microscope. Out of 150 fish samples collected, 79 samples were found to be infected with helminths. In these infected samples, a total of 576 parasites (Acanthocephala= 312, Nematoda= 264) were isolated. Infection rate varied among fish families with Family Leiognathidae recording the highest infection level. High intensity of infection and dual infection were observed only in Leiognathus equulus, while other species were infected only with either acanthocephalans or nematode parasites. Overall, acanthocephalan infection was observed only in Family Leiognathidae, while nematode infection was observed in all fish families sampled. Interestingly in mullids, parasitic nematode infection showed a significant positive correlation with body length (ρ=0.012). The differential parasitic infection observed across demersal fish families sampled could be attributed to the host’s size, feeding behavior, and parasite biology. Initial results of the study suggest wide distribution of gastrointestinal parasites in commercially important food fishes caught in Manila Bay.

This study was conducted to isolate and identify the putative pathogenic Vibrio species dominantly present during the first 10 days of mangrove crab, Scylla serrata larval culture and test the isolates’ susceptibility to antibiotics. Dominant colonies of Vibrio were periodically isolated based on their colonial morphology on thiosulfate citrate bile sucrose (TCBS) agar and nutrient agar supplemented with 2% NaCl (NA+) plates. Conventional biochemical and physiological tests revealed the existence of 4 dominant groups belonging to 4 species including V. campbellii, V. proteolyticus, V. alginolyticus and V. tubiashii. Furthermore, through 16S rRNA gene sequencing, the taxonomic position of each representative strain randomly selected from the 4 dominant groups of Vibrio spp. Was ascertained. Moreover, the in vitro susceptibility of the 4 representative Vibrio spp. to commercially available antibiotic discs including amoxicillin, oxolinic acid, tetracycline, kanamycin, ampicillin, trimethoprim and cefprozil were examined. Results showed that all four species were susceptible to tetracycline, oxolinic acid and trimethoprim, however, the susceptibility of V. campbellii and V. proteolyticus to trimethoprim were just intermediate. The susceptibility of the Vibrio isolates to the rest of the commercial antibiotic discs were either intermediate or resistant. In addition, the minimal inhibitory concentration (MIC) assay was conducted using oxytetracycline (OTC) concentrations ranging from 10 to 50 mg L-1. Results showed that V. tubiashii was susceptible to at least 10 mg L-1 OTC, while V. campbellii, V. alginolyticus and V. proteolyticus were susceptible to at least 30, 40 and 50 mg L-1 OTC respectively. Current data clearly indicate that OTC is a suitable candidate for the treatment and prevention of vibriosis in S. serrata larval culture with at least 50 mg L-1 required to inhibit all the four putative pathogenic Vibrio spp. tested.

Ivatan fishers in Batanes Province belong to the municipal fishery sector, and many use various types of handline gears apparently because these gears are simple to operate. A census of handline gears was made and details of the fishing operations of six handline gears in February to May 2019 based from interviews, actual participation with fishing operations, and field enumeration are presented. The most dominant gear is the simple handline panayrin, which is used during the daytime. Fishers using a simple handline (payavavang) spend longer fishing hours, but their catch per unit effort is lower than that of simple handline (panayrin) fishers. Because it is more numerous and can be used more frequently throughout the year, payanrin contributes about 70% of total handline fish production. Technically, Ivatan fishers are municipal fishers because the scale of their operations is small-scale and their fishing grounds are confined well within the territorial zone of the province. The field observations revealed that many Ivatan fishers do not use boats when they use two minor handline gears, pole and line (pasid) and underwater hook and line (pangna), and the relatively modern rod and reel, simply called fishing rod in Batanes, in the nearshore zone, and usually bring their catch directly to their places of residence, suggesting that this portion of the overall catch is not reflected in estimates of annual total fish production. Although the contribution of these three nearshore gears seems low, this observation warrants another look, perhaps together with other non-handline gears to properly account for the total fish production of the province.

The whale shark is the world’s largest fish yet 60-90% of its diet is made up of the smallest prey, the zooplankton. The species is listed as endangered under the International Union for Conservation of Nature Red List of Threatened species. The biology and ecology of this species are largely unknown. Although parts of their movements have been mapped out, their food, which plays a major role in their travels and habitat use, is hardly studied. We therefor analysed zooplankton community composition along whale shark aggregation sites in Pintuyan, Southern Leyte, where sharks occur seasonally from November to June; and Oslob, Cebu, where they are hand-fed and found daily year- round. Water samples were taken in stations in each site during November 2014, January and February, 2015. In both sites with mostly microzooplankton of the Order Tintinnida was the most abundant group with a density of 2,000 indiv/m³ and 3,000 indiv/m³ in Pintuyan and Oslob, respectively. Other zooplankton observed were from classes Appendicularia, Ascidia, Bivalvia, Crustacea, Gastropoda, Ophiuroidae, Polychaeta, and Sarcodina. In total, the densities in both sites were not significantly different. Oslob registered a density value of 5,000 indiv/m³ and SB had 4,000 indiv/m³. In contrast, Pintuyan had a higher diversity value (2.75) than Oslob (2.36). Our results highlight that although whale sharks were not actively feeding near the sampling sites, the waters near their feeding sites are both abundant and rich in zooplankton diversity. Further studies to quantify and understand their target prey are needed.

The population dynamics and reproduction of the limpet Patelloida saccharina (Linnaeus, 1758) on rocky shores in Taklong Island, Guimaras were examined in September 2016 (Southwest monsoon; SW) and December 2016 (Northeast monsoon; NE). Transects were laid parallel to the shore at five different tidal heights and 10 quadrats (25cm x 25cm) were placed randomly along each transect. Shell lengths (SL) of limpets encountered in each quadrat, at every tidal height, were measured to the nearest 0.1 mm using a Vernier caliper. Limpets were observed to occupy the low shores, with sizes ranging from 5.5 to 39.3 mm during the SW monsoon and 3.2 to 38.9 mm during the NE monsoon. P. saccharina showed a significant seasonal pattern whereby more limpets were observed during the SW monsoon (108 ind) than the NE monsoon (78 ind). A separate group of 30 limpets, during each season, was also collected to investigate the reproductive characteristics, with SLs ranging from 20.7 – 32.8 mm for females and 21.9 – 34 mm for males. Sex ratio between males and females showed no significant differences between sampling periods (p > 0.05). Investment in gonads during the SW monsoon was higher than during the NE monsoon, showing seasonal differences in reproductive effort, with females showing higher GSI compared to males. The higher abundance and increased reproductive investment during the SW monsoon may indicate seasonal differences in food availability or a general reduction in external stress. Further research to elucidate the cause of the observed differences is needed.

This study is the first report on the fisheries industry in Gigantes Islands, Carles, Philippines, highlighting its scallop fishery. Focused group discussions were done in North and South Gigantes Islands on January 2014 to provide estimates of yield, fishing pressure and other fishery parameters, which can be primarily used to manage the resources. Information on fishing gear types used, fishing seasonality, and estimated catches were gathered. Gigantes is exposed to fishing pressure of 8,811.9 trips km-2 yr-1, which is much higher compared to other larger local fishing grounds in the Philippines. The total estimated annual catch of North Gigantes is 9,941.2 MT and 6,479.6 MT for South Gigantes. Compressor diving targeting scallops and the oysters contributed about half of the total estimated annual catch, landing a total of 8,473.5 MT. This high record of catch landings may already dictate that the current extraction rates should no longer be increased.