Third International Symposium on Mangroves As Fish Habitat Abstracts*
Total Page:16
File Type:pdf, Size:1020Kb
Bull Mar Sci. 96(3):539–560. 2020 abstracts https://doi.org/10.5343/bms.2019.0047 Third International Symposium on Mangroves as Fish Habitat Abstracts* COMMUNITY COMPOSITION AND DIVERSITY OF PHYTOPLANKTON IN RELATION TO ENVIRONMENTAL VARIABLES AND SEASONALITY IN A TROPICAL MANGROVE ESTUARY, MALAYSIA by ABU HENA MK, Saifullah ASM, Idris MH, Rajaee AH, Rahman MM.—Phytoplankton are the base of the aquatic food chain from which energy is transferred to higher organisms. The community and abundance of phytoplankton in a tropical mangrove estuary were examined in Sarawak, Malaysia. Monthly-collected data from January 2013 to December 2013 was pooled into seasons to examine the influence of seasonality. The estuary was relatively species-rich and a total of 102 species under 43 genera were recorded, comprising 6 species of Cyanophyceae, 4 species of Chlorophyceae, 63 species of Bacillariophyceae, and 29 species of Dinophyceae. The mean abundance (cells L−1) of phytoplankton was found in the following order: Bacillariophyceae > Dinophyceae > Cyanophyceae > Chlorophyceae. Mean abundance of phytoplankton ranged from 5694 to 88,890 cells L−1 over the study period, with a higher value in the dry season. Species recorded from the estuary were dominated by Pleurosigma normanii, Coscinodiscus sp., Coscinodiscus centralis, Coscinodiscus granii, Dinophysis caudata, Ceratium carriense, Ceratium fusus, and Ceratium lineatum. Abundance of phytoplankton was positively influenced by chlorophyll a (R = 0.69), ammonium (R = 0.64), and silica (R = 0.64). Significant differences (ANOSIM and NMDS) were observed in the species community structure between the intermediate and wet season. The species assemblages were positively correlated with surface water temperature, salinity, pH, ammonium, and nitrate in the intermediate and dry season toward larger species composition in the respective seasons, whereas silica influenced species assemblage in the wet season. The findings suggest that the mangrove estuary in Sarawak is productive in terms of the diversified fishery resources like phytoplankton, which are influenced by hydrobiological factors.—UPM Campus Bintulu, Faculty of Agriculture and Food Sciences Universiti Putra Malaysia Campus Bintulu Sarawak 97008 Bintulu, Sarawak, Malaysia. Email: <[email protected]>. * Listed in alphabetical order by presenting author (in bold). Bulletin of Marine Science 539 © 2020 Rosenstiel School of Marine & Atmospheric Science of the University of Miami 540 Bulletin of Marine Science. Vol 96, No 3. 2020 THE CAUSES AND CONSEQUENCES OF MANGROVE HABITAT LOSS IN PENINSULAR MALAYSIA by ALDRIE AA, Khirotdin RPK, Helfer V, Zimmer M.—As Malaysia progresses to become a high-income economy, development continues to increase at the expense of natural resources and the environment. Mangroves are one particular down-stream habitat, especially in Malaysia and in the southeast Asia region, that has suffered direct impacts of land-use change for socioeconomic development. Due to various reasons, mangrove area has decreased significantly, especially in the final quarter of the past century, related to the period when the country’s growth was most rapid. This presentation showcases significant spatiotemporal changes in iconic mangrove habitats of Peninsular Malaysia. This study quantifies the extent and explains the causes of these changes, and describes how these changes actually correspond to local, national, and regional development from Malaysia’s independence to present day. This study critically discusses the implications of mangrove loss on their connectivity with the adjacent habitats, namely: (1) mudflats, (2) seagrass beds, (3) coral reefs, (4) islands, bays, and lagoons, (5) rivers, estuaries, and deltas, and (6) inland hinterland.—Institute for Environment & Development (LESTARI), Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia. Email: <[email protected]>. INVESTIGATION ON THE CHANGES OF MANGROVE TREES IN RABIGH LAGOON SWAMPS USING REMOTE SENSING AND GEOGRAPHIC INFORMATION SYSTEM (GIS) TECHNIQUES by ALJAHDALI MO.—Due to changes caused by anthropogenic catastrophes on the hydrology of Rabigh lagoon system, approximately 49.35% of the originally 490 ha of mangrove forests have been destroyed between 1987 and 2012. However, during 2013 to 2017, some healthy mangrove trees remained along the lagoon with 30% enhancement compared to those in past seasons. The main objective of this study was to detect the changes of mangrove forest canopy in Rabigh lagoon using remote sensing and GIS imagery. Landsat images between 1987 and 2015 were acquired for analysis. These images were accurately calibrated, smoothly filtered, and radiometrically corrected, and then human constructions, normalized difference vegetation index (NDVI), mangroves distribution, and changes between 1990 and 2017 were estimated. Data indicated that the degradation of mangrove cover began in 1988 when the lagoon was mostly enclosed by a passageway. This was partly modified in 1990, when the mangrove forests linked again with the open system of the Red Sea through narrow streams. The recharged water in the swamp was low until 2012 when the lagoon was mostly liberated. Mangrove forests were severely degraded between 1990 and 2000, especially in the islands and northern parts of the lagoon. The total area of mangrove forests decreased from 490.4 ha in 1990 to 286 ha in 2000, and to its lowest amount of 248.8 ha in 2012. In contrast, the mangrove area gradually recovered and increased to 342.8 and 380 ha in 2014 and 2017, respectively.—Department of Biological Sciences, Faculty of Science King Abdulaziz University, P.O. Box 80203, Jeddah 21589, Saudi Arabia. Email: <[email protected]>. DIVERSITY AND POPULATION DYNAMICS OF FISHES IN THE MANGROVE ESTUARY OF MARUDU BAY, MALAYSIA by Mohd Azim MK, AMIN SMN, Arshad A.—Habitat ecology and population dynamics parameters were determined by analyzing fish samples collected from the mangrove estuarine area of Marudu Third Int Symp on Mangroves as Fish Habitat: Abstracts 541 Bay, Sabah, Malaysia between October 2012 and September 2013. There were five sampling stations for the study, and each sampling station was approximately 1 km apart from each other. Fish samples were collected by using gill nets. In total, 40 fish species belonging to 29 families were identified from the mangrove estuarine waters of Marudu Bay, Sabah, Malaysia. The abundance of 40 species was found to be correlated (positive or negative) with water parameters. The highest and significant regression coefficient was observed for Pseudorhombus cinnamoneus, which indicated that 29% of their abundance was influenced by the major water parameters and the remaining 71% by other factors. The growth, mortality, recruitment, and relative yield per recruit of the five selected dominant fish speciesRastrelliger ( kanagurta, Gerres oyena, Atule mate, Sillago sihama, and Sardinella melanura) from Marudu Bay were investigated based on monthly length-frequency data, using FiSAT software. In terms of length-weight relationships, G. oyena, S. sihama, and S. melanura showed a negative allometric nature of growth, while R. kanagurta and A. mate showed a positive allometric nature of growth in Marudu Bay. Only G. oyena had a continuous recruitment pattern with only one major cohort produced per year, while the four other species (R. kanagurta, A. mate, S. sihama, and S. melanura) showed two major recruitment events per year, indicating two cohorts were produced in a year. Results from the analysis of the exploitation rate (E) based on the fishing mortality estimates indicate that the fishery of the selected five dominant fish species in Marudu Bay were slightly below the optimum level of exploitation. This implies that the fish stocks in Marudu Bay are still abundant, but any further unrestrained increase in fishing effort in the future might drive the fish stocks down and lead to economic losses.—Laboratory of Fisheries Biology and Aquatic Ecology, Department of Aquaculture, Faculty of Agriculture, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia. Email: <[email protected]>. SPATIOTEMPORAL VARIATION OF LARVAL FISHES AT MATANG MANGROVE ECOSYSTEM, PERAK, MALAYSIA by ARA R, Hishamudin M, Amin SMN, Yusoff FM, Arshad A.—Spatiotemporal variations of larval fishes were investigated in the Matang Mangrove ecosystem, Perak, in the dry season (May– July 2015) and wet season (November 2015–January 2016). Three sampling stations were selected: St 1 (least disturbed, Sungai Tiram Laut), St 2 (moderate disturbed, Sungai Tinggi), and St 3 (most disturbed, Sungai Sepetang). Samples were collected using Bongo net equipped with a flow meter. The mean (SD) values of temperature, dissolved oxygen, salinity, pH, and total dissolved solids in the investigated areas were 29.64 °C (0.26), 3.92 mg L−1 (0.29), 19.72 (2.12), 7.12 (2.12), and 21.03 mg L−1 (2.01), respectively. There were significant variations in salinity and total dissolved solids among the investigated areas. However, no significant variations were observed in temperature, dissolved oxygen, and pH among the investigated areas. There were significant variations in salinity, temperature, and total dissolved solids among months during the study period. However, no significant variations were observed in dissolved oxygen and pH among the different months. In total, more than 4711 larval fishes were sorted and checked and 15 families were identified from the investigated areas. Among them, nine families were