Mariculture Pond Ecology with Emphasis On Environmental Quality and Production of Penaeus Monodon (Fabricius)

In the present study, mariculture pond ecology with special reference to environmental quality and tiger shrimp Penaeus monodon production in old culture ponds (>3 years) and new culture ponds (4 year) were investigated throughout the culture period in Malacca, Malaysia. The study showed that the cation exchange capacity (CEC) varies with soil texture while soil organic matter varied with the culture pond age. The concentrations of major cations depends on cation exchange capacity of soils attributed partly to chemical bonding or adsorption of colloids. Deposition of nutrient loaded suspended solids through uneaten feeds and other culture activities led to increase in the concentrations of macro and microelements onto the pond bottom at the end of the culture period. The dynamics of macro and microelements in pond and sediment waters were not distinct in old and new culture ponds throughout the culture period, but were influenced by accumulation process of living organisms, water exchange and precipitation of major cation as organic and inorganic particles. Major groups of the macro and meiobenthos comprised of gastropods, polychaetes, bivalves, crustaceans, ostracods, nematodes, insects and crab larvae. Gastropods were the dominant group of macrobenthos followed by harpacticoid copepod as meiobenthos throughout the culture period. The growth of shrimp was related with the macrobenthos (r=0.62, p<0.05) and meiobenthos abundance (r=0.67, p<0.05) in the culture ponds. The major groups of zooplankton in the ponds were copepods, rotifers, sergestidae, luciferans, gastropod larvae, bivalve larvae, pelagic polychaetes, nematodes, crustacean nauplii, insects and mysids. About 18-30% of the total zooplankton population decreased within one month after the release of post larvae into the ponds which revealed the significance of natural foods in culture ponds in reducing the production cost and increasing pond yield. Stomach content analysis showed that the stomach of shrimps contained a wide variety of items depending on the availability of benthic and pelagic organisms in the ponds. Higher content of natural food items were found in the stomach of shrimps collected from the old culture ponds than the new culture ponds. Although a commercial feed was provided, the juvenile, sub adult and adult P. monodon were found to be opportunistic omnivorous scavengers feeding on variety of benthic materials and organisms such as detritus, crustacean, molluscs, polychaetes, rotifers and phytoplankton. In the group of Crustacea, copepods were the major food item preyed by all stages of the shrimps throughout the culture period in the ponds. The diversity of fungi increased at the end of culture period in both old and new culture ponds. The proliferation of fungi in general could be due to shrimp faeces and high carbon source from uneaten feeds as the culture progressed. The present study revealed that population of fungi in shrimp pond sediments were mostly of the genera of Aspergillus and Penicillium which were similar to the terrestrial soil fungi. The results showed that many activities such as feeding, nutrient status, stocking density, weather conditions, accumulation of organic matters, biological factors and pond age governed the quality of pond water, shrimp growth, production and pond ecosystem during the culture period

Seasonal changes in Porteresia coarctata (Tateoka) beds along a subtropical coast

Shoot density, standing crop (above- and below-ground biomass) and habitat of salt marsh grass Porteresia coarctata were investigated along the coast of Bakkhali estuary, Cox's Bazar, Bangladesh from January to December 2006. Shoot density of P. coarctata was influenced by season and was found to be higher (>2 500 shoots/m2) in post-monsoon and minimal in monsoon season; plants were particularly active in vegetative propagation during pre-monsoon. Above-ground biomass was greater along the protected coast compared with the exposed one in this estuary. Below-ground biomass was higher (7. 75-269. 53 g DW/m2) than that above ground (2. 20-114. 75 g DW/m2). Standing crops of P. coarctata showed a negative relationship (R =-0. 77; P <0. 05) with sedimentation rate, while seasonal activity influenced sedimentation. The recorded sedimentation rate was lower (6. 09 mg/(cm2·d)) in pre-monsoon and highest (14. 55 mg/(cm2·d)) in monsoon season. The mean value of pore water salinity was higher (34. 25±5. 05) during post-monsoon and lowest (18. 0±3. 71) in monsoon season. The soil was sandy clay in this P. coarctata bed; it consisted of 86% sand, 13% clay and 1% silt. Soil organic matter dropped during the monsoon season (0. 78%-0. 67%) and was highest ((2. 17±1. 42)%-(2. 3±1. 47)%) during post-monsoon, probably owing to accumulation of decomposed peat on the marsh surface. The mean pore water NH4-N concentration ranged from 2. 44±1. 65 to 3. 33±1. 82 μg/L, with a minimum air temperature of 22. 09°C in post-monsoon and a maximum of 31. 16°C in pre-monsoon. Variations of physico-chemical parameters in the soil, water, and climate governed biological parameters of P. coarctata in the Bakkhali estuary, and were comparable with estuarine environments elsewhere

Growth and production of seagrass Cymodocea serrulata (R.Br.) aschers et magnus and thalassia hemprichii (ehrenb.) aschers in Port Dickson, Negeri Sembilan, Malaysia

Seagrass is one of the valuable components which contribute significantly in coastal productivity and stabilizing sea floor sediments in the shallow marine water ecosystems. Investigation on the shoot density, biomass, leaf growth, leaf production and habitat of two seagrasses, Cymodocea serrulata and Thalassia hemprichii, in a sparse, mixed stand and monospecific patches of Batu Tujuh, Port Dickson coastal area Negeri Sembilan, Malaysia are reported. Shoot density and biomass of these species was detected by placing 20 x 20 cm quadrat. Leaf growth and production was detected by leaf marking method. The mean shoot density was 950 ± 136.42 shootslm2 and 632.14 ± 113.77 shoots/m2 for C. serrulata and T. hemprichii, respectively. Above ground biomass of T. hemprichiiwas lower (13.878 ± 1.173 g AFDW/m2) when compared to those of C. serrulata (20.250 ± 4.053 g AFDW/m2). The mean leaf growth of C. serrulata was higher (7.66 mm/shoot/day) compare to T. hemprichii (7.04 ± 1.35 mm/shoot/day). The present study indicates that the seagrass C. serrulata and T. hemprichii contributes a countable portion (0.961 ± 0.227 g AFDW/m2/day for C. serrulata and 0.563 ± 0.172 g AFDW/m2/day for T. hemprichil) of organic matter, together with phytoplankton and macro algae, to the total primary production in Port Dickson marine water. Relative production rates (RPR) was 0.057 ± 0.014 gig AFOW/day for C. serrulata ant1 0.058 gig OW/day for T. hemprichii. This result indicated that T. hemprichii produce more organic matter daily than C. serrulata in this marine area. The plastochrone interval of C. serrulata leaves was higher (14.74 ± 1.89 days) than T. hemprichii (12.03 ± 1.01 days), whereas, short plastochrone interval of leaves (PIL) allows a faster plant response than the long PIL. Dissolved oxygen and pH value of seawater of Batu Tujuh seagrass bed ranged between 7.8 - 8.8 mgll and 8.0 - 8.5, respectively. The range of salinity and light intensity were 24.0-30.0 ppt and 25.0- 1805.2 IJmoVm2/s, respectively. Concentrations of nutrients were greater in pore water than overlying seawater of this seagrass bed. Total nitrogen content of plant tissue varied between 0.349 ± 0.024 and 1.110 ± 0. 067% of OW in C. serrulata and 0. 195 ± 0.036 - 1.586 ± 0.041 % of OW in T. hemprichii. Total phosphorus was highest in leaves (0.276 ± 0.022 - 0. 377 ± 0. 034% of OW), intermediate values in rhizomes (0.157 ± 0.004 - 0.196 ± 0.021 % of OW) and lowest in roots (0.100 ± 0.004 - 0. 114 ± 0.003% of OW). Potassium content was relatively higher in C. serrulata leaves (2.267 ± 0.058% of OW) and roots (2.20 ± 0.50% of OW) in T. hemprichii. In situ photosynthesis varied at different depths. The highest rate of photosynthesis of both species was higher at 0.5 m depth than at 2. 0 m and this could be attributed to relatively higher light intensity at depth of 0.5 m. The respiration rate remained uniform at different depths for both species. Experimental photosynthesis study showed that the light saturation was reached at 200 - 800 and 400-800 µmol/m²/s for C. serrulata and T. hemprichii, respectively. The compensation light intensity was 20 - 40 µmol/m²/s for C. serrulata and around 20 µmol/m²/s for T. hemprichii. Comparing these results to in situ light measurements from the seagrass bed, it may be assumed that both seagrasses could penetrate deeper area in this seagrass bed. However, the photosynthesis produced at light intensity below 2.0 m depth «108.33 ± 9.177 µmol/m²/s for C. serrulata and <115 ± 1.512 µmol/m²/s for T. hemprichil) probably could not support the requirement during dark period, albeit lower light compensation (20-40 µmol/m²/s for C. serrulata and ± 20 µmol/m²/s for T. hemprichil) showed in the experimental study

Zooplankton community structure in the tiger shrimp (Penaeus monodon) culture pond at Malacca, Malaysia

In aquaculture pond, zooplankton offer themselves as food to culture organism likes shrimp. Biomass and productivity of zooplankton in different size ranges are important factors modifying the productivity of higher trophic-level organisms as well as production of culture. In this view point, the composition of zooplankton was investigated in shrimp culture ponds for one culture cycle in the tropics. Zooplankton abundance did not differ significantly between old and new culture ponds. The major groups of zooplankton were copepods, rotifers, sergestidae, lucifer, gastropod larvae, bivalve larvae, pelagic polychaetes, nematodes, crustacean nauplii, insects and mysidacea. Among these, copepods (51.69-53.57%) and crustacean nauplii (28.39-41.81%) were the dominant groups in all culture ponds. Zooplankton density increased by >46% at the end of the culture period in all ponds probably due to the recruitment of zooplankton through reproduction in the ponds over time. The findings of this study suggests that zooplankton composition in culture ponds appeared to be an important source of food and nutrition for shrimp post larvae, at least for earlier period (1-4th week) after the ponds are stocked, hence managing of zooplankton density prior to stocking of post larvae in the culture pond is important

Perceptions of sex educators: A qualitative analysis

The fear of children getting victimized by strangers is the basis for several current pieces of legislation, specifically Megan’s law, despite the lack of corresponding empirical data. This legislation causes significant negative consequences for those who are on the registry, especially for juvenile offenders as they have unique challenges they face regarding labeling and societal reintegration. As most juveniles receive most of their sex education in school, and a lack sex education is a contributing factor to the commission of sex offenses, this study aims to explore a proactive method of preventing sex offenses. This study includes exploratory interviews with sex education teachers to highlight the critical gap between training for sex education and teaching sex education, and the difference between teaching sex education and knowledge about sex offenses. This study opens the dialogue regarding these connections and calls for proactive thinking in preventing juvenile sex offenses

Analyzing Spatial Variability of Social Preference for the Everglades Restoration in the Face of Climate Change

The South Florida Everglades is a unique ecosystem. Intensive water management in the system has facilitated agricultural, urban, and economic development. The Everglades offers a variety of ecosystem services (ES) to the people living in this region. Nevertheless, the ecosystem is under imminent threat of climate change, which would alter the way water is managed today and ultimately affect the ES offered by the system. On the other hand, substantial restoration is underway that aims to restore the Everglades closer to its historic condition. This research tried to map the public’s preference for Everglades restoration. Using a geocoded discrete-choice survey dataset, the study showed variation in the public’s preference by changing the levels of ES. Additionally, the general public’s attitude toward climate change risk to the Everglades and preference for mitigation were also assessed using the survey data

Taxonomic composition and abundance of zooplankton Copepoda in the coastal waters of Bintulu, Sarawak, Malaysia

The abundance and composition of copepod was carried out in the coastal waters of Bintulu, Sarawak, Malaysia on March 2005. Samples were collected using conical plankton net with the mesh size of 153 μm. Copepod identified comprised of four orders namely, Calanoida, Cyclopoida, Harpacticoida and Poecilostomatoida. A total of 49 species belonging to 26 genera were identified. Nine most abundant species were Paracalanus crassirostris, Paracalanus elegans, Temora stylifera, Temora turbinata, Oncaea venusta, Corycaeus andrewsi, Corycaeus subtilis, Paracalanus parvus and Paracalanus denudatus. The first four species mentioned were the most abundant species and they accounted for over 50% of the total numbers of identified copepods. Copepod species which were rare and low in abundance included Delius nudus, Acrocalanus gracilis, Tortanus forcipatus, Centropages orsini, Corycaeus dahlia, Copilia mirabilis, Labidocera minuta, Microstetella rosea and Cosmocalanus darwini. Cosmocalanus darwini is new record to Malaysian waters. Species richness and diversity tends to increase towards the offshore while abundance increased towards the inshore stations

Taxonomic study of edible bivalve from selected division of Sarawak, Malaysia.

The diversity of edible bivalve was conducted from August 2010 to July 2011 covering eight divisions i.e., Kuching, Sarikei, Sibu, Mukah, Bintulu, Miri, Limbang and Lawas of Sarawak, Malaysia. Samples were collected from native market and fishing village during the study period. All edible bivalves inhabit either in brackish or marine environment and comprised 19 species from 10 families namely Meretrix meretrix, M. lyrata, Paphia undulata, Circe scripta, Solen regularies, Solen lamarckii, Pharella acutidens, Amusium pleuronectes, Anadara granosa, Pholas orientalis, Gluconome virens, Placuna placenta, Crassotrea lugubris, Isognomon ephippium, Polymesoda erosa, P. bengalensis, P. expansa, Anadonta woodina and Pilsbryoconcha exilis. The diversity of edible bivalves was found highest in Kuching and Bintulu compared to other divisions studied in Sarawak. The bivalve species at Sarawak could have economic potentiality in terms of protein source, livelihoods of local tribes and economic value. Study suggests that if the high conservation and management of edible bivalve diversity could establish in the coastal and wetland area of Sarawak, a remarkable and vast economic return could achieve

Diversity of edible mollusc (Gastropoda and Bivalve) at selected division of Sarawak, Malaysia.

Diversity of edible mollusc was studied at eight divisions of Sarawak from August 2010 to May 2011. At each division, diversity and number of species were collected from road site selling out lets and local wet markets. Total number of mollusc was comprised of 29 species namely Solen regularies, S. lamarckii, Pharella acutidens, Anadara granosa, Pholas orientalis, Gluconome virens, Circe scripta, Anodonta woodina, Paphia undulata, Amusium pleuronectes, Meretrix meretrix, M. lyrata, Polymesoda bengalensis, P. erosa and P. expansa for bivalve and Cerithidea rizophorarum, C. obtusa, Telescopium telescopium, Clithon retropictus, Nerita articulate, N. chamaeleon, N. albicilla, Ellobium aurisjuda, Trochus radiates, Planaxis sulcatus, Monodonta labio, Turbo crasus, Thais aculate and Melo melo for gastropod. The species number of bivalve was recorded highest (15 species) in mollusc group from Sarawak. Mollusc diversity was found highest (14 species) in Bintulu and lowest (1 species) in the division of Sarikei. From this study, there is a wide chance of research to further explore both on the possibility of commercial value and ecosystem conservation

Reproductive cycle of hard clam, Meretrix lyrata Sowerby, 1851 (Bivalvia: Veneridae) from Sarawak, Malaysia

A study of the reproductive cycle of the hard clam, Meretrix lyrata, was documented based on histological observation and Gonad Index (GI). Samples were taken from estuarine waters of the Buntal River in Sarawak, Malaysia. The gonad of M. lyrata started to develop in September 2013. Gametogenesis continued to develop until the maturation and spawning stage from February to April 2014. The GI pattern for a one-year cycle showed a significant correlation with chlorophyll a. The corresponding GI with chlorophyll a suggested that the development of the reproductive cycle of M. lyrata required a high amount of food to increase gametogenesis