Measurement Of Environmental Parameters Research Articles

Viability Test of Hydrocarbonoclastic Bacteria Consortium Entrapted on Sawdust Material

Oil spills in the sea are generally prevented in various ways, one of them is the bioaugmentation method through bacterial entrapment on sawdust carriers. The entrapment of bacteria is one of the bacterial immobilization techniques. The potential of bacterial consortium on sawdust is still not widely used, especially in long-term storage. The purpose of this study was to obtain the viability of hydrocarbonoclastic bacterial consortium on sawdust after 0, 7, and 41 days of storage. The bacterial consortium consists of Bacillus aquimaris, B. megaterium, B. pumilus, Halobacillus trueperi, and Rhodobacteraceae bacterium. The samples were tested by culturing the immobilized bacterial consortium of 0, 7, and 41 days on falcon tubes containing crude oil and seawater. The viability of the immobilized bacterial consortium was tested for 28 days (days 0, 7, 14, 21, and 28) by enriched the bacterial populations periodically. The viability test was also supported by the measurement of environmental parameters on the 1 st day and the 28 th day such as DO, pH, salinity and, temperature. The results show that bacterial consortium in all storage periods was viable on sawdust carriers which related to the high number of bacterial populations on the 28 th day. The most viable bacterial consortium on sawdust was the 0-day storage (9.59 x 10 8 CFU/ml) which was indicated by the increases phase at the end of the day. It was proved that the bacteria are still productive and could degrade petroleum hydrocarbons.

Assessment of thermal comfort levels in aviary workers

Abstract Background The occurrence of biohazards in avian work environments has been a cause of concern. Additionally, studies on this working environment carried out by Health and Safety at Work professionals are scarce. The weaknesses of birds regarding ideal temperatures for development, depending on their gestational stage is well known. Now it is important to look into the effects temperatures inside the aviaries have on workers and specifically the contrast of these with external temperatures in winter time. Methods The goal of this study is to assess thermal comfort through the use of the PMV (Predicted Mean Vote) and PPD (Predicted Percentage of Dissatisfied) indexes. It was carried out at 8 aviaries belonging to two separate companies, located in Portugal. The target-population was the workforce of the two companies, making up a total of 6 employees. Measurements of environmental parameters were carried out (radiating temperature, relative humidity, air temperature and air speed), as well as individual parameters related to thermal comfort (metabolic rate and thermal resistance of workers clothing) inside and outside the aviaries. This study is classified as a level III (co relational) observational and analytical study, with a cross-section cut and a convenience non-probabilistic sampling type. Results The thermal discomfort suffered by these workers in an avian environment was noteworthy, when exposed to different, contrasting temperatures, particularly in the winter season. Conclusions Despite the different personal characteristics, it is possible to create environments that are thermally acceptable, that is, to satisfy the majority of its occupants.

ANALISIS TINGKAT KESESUAIAN WISATA BAHARI PADA EKOSISTEM TERUMBU KARANG DI PULAU LAREA- REA KABUPATEN SINJAI

Coral reefs are one of the marine tourism potentials that need to be managed in a sustainable manner by looking at the suitability of tourism and the carrying capacity of the environment. Data on the potential for coral reefs will support government programs related to conservation and rehabilitation of coastal and marine ecosystems as a focus area for maritime research. This study aims to determine the potential and percentage of coral reef cover, know the tourism suitability index and environmental carrying capacity, know the direction of coral reef ecosystem management. The research method is using UPT (Underwater Photo Transect), as well as measurement of environmental parameters on Larea-rea Island. Data analysis using CPCe 4.1 software, and Arcgis 10.8 (Kismanto et.al, 2018). Than, an analysis of the suitability of diving tourism and an analysis of the carrying capacity of the area is carried out (Yulianda, 2018).Coral reefs are one of the marine tourism potentials that need to be managed in a sustainable manner by looking at the suitability of tourism and the carrying capacity of the environment. Data on the potential for coral reefs will support government programs related to conservation and rehabilitation of coastal and marine ecosystems as a focus area for maritime research. This study aims to determine the potential and percentage of coral reef cover, know the tourism suitability index and environmental carrying capacity, know the direction of coral reef ecosystem management. The research method is using UPT (Underwater Photo Transect), as well as measurement of environmental parameters on Larea-rea Island. Data analysis using CPCe 4.1 software, and Arcgis 10.8 (Kismanto et.al, 2018). Than, an analysis of the suitability of diving tourism and an analysis of the carrying capacity of the area is carried out (Yulianda, 2018). The results of this study indicate that the percentage of potential coral reef cover at all stations is 10-36%, indicating that the coral condition is not good (according to the conditions). Damage to coral reef ecosystems due to environmentally unfriendly fishing activities (Wardani, 2018). The number of lifeform types ranged from 8-12, while the number of fish species obtained was 37-44 species. The suitability class category based on the results of the analysis at the three stations obtained the appropriate category (S2), with a percentage of the IKW value of 50-67% (Yulianda, 2018). Then, area carrying capacity (DDK) in the diving tourism category is an average of 528 people / day from the three stations. Management and development of marine tourism can be done by determining the zone of utilization and rehabilitation of coral reef ecosystems, as well as limiting visitors for certain periods to reduce the potential impact of environmental degradation.

Keanekaragaman dan Pola Distribusi Tumbuhan Paku di Taman Hutan Raya Sultan Adam Mandiangin

The research aims to analyze the diversity of ferns, to know the distribution pattern and potential of ferns in TAHURA Mandiangin Sultan Adam. The research included sampling, measurement of environmental parameters as supportive data, identification of ferns samples, and data analysis. The research was conducted from October to December 2011. The research showed that, at different heights there are 548 individuals consisting of 16 species of ferns, including the 8 species of terrestrial and 8 kinds of epiphytic. Ferns are included into two classes, namely, Filicine and Lycopodinae, 6 Order, and 8 families are scattered at heights different. Indices of diversity in zone I-II showed diversity index is medium, in zone III has low species diversity. Distribution pattern is Uniform. The Location of existing research that can be used as ornamental plants, medicinal herbs, and vegetables.

Study on the effect of home night lighting environment on students’ eyestrain and visual efficacy

China has the highest incidence rate of myopia, and the number of teenagers with myopia accounts for more than half of the total number of myopia in the world. In recent years, With the increase of youth night home learning time, the impact of the night lighting environment in the home learning space on eye health has become increasingly obvious. This paper selects 112 home learning spaces of middle school students to carry out the actual measurement of lighting environment parameters and the satisfaction survey of the lighting environment, and through comparative experiments to explore the effects of illuminance, color temperature and lighting methods on eyestrain and visual efficacy. This Study found that under mixed lighting conditions, when the color temperature is 4500k, the illuminance in the range of 500lx-750lx is beneficial to relieve eyestrain and improve visual efficacy; When the illuminance is 500lx, a low color temperature (3500k) can help relieve eyestrain, and a high color temperature (6000k) can improve visual efficacy better. In addition, mixed lighting is better than local lighting for relieving eyestrain and improving visual efficacy. The results will help improve the night lighting environment in the home learning space of middle school students.

Bryophyta di Sekitar Kawasan Bandar Udara Internasional Syamsudin Noor Kalimantan Selatan

The diversity of mosses around the Syamsudin Noor international airport was never reported. This study aimed to reveal the variety of moss around the Syamsudin Noor International Airport area. This research uses the purposive sampling method. Measurement of environmental parameters includes air temperature, light intensity, humidity, and soil pH. Moss identification refers to the book A Handbook of Malesian Mosses volume 1 Sphagnales to Dicranales and A Handbook of Malesian Mosses volume 2 Leucobryaceae to Buxbaumiaceae. The moss morphological characters observed included the leaves, stems, and rhizoids using a stereomicroscope. The results showed that in Syamsudin Noor International Airport's vicinity, there are as many as five types of moss consisting: Pseudoracelopus acaulis, Hyophila apiculata Homalothecium lutescens, Ectropothecium falciforme, Fissidens atroviridis. The most dominant type of moss is Pseudoracelopus acaulis. The range of environmental parameter values ??is air temperature 28-34oC, light intensity 20-35 lux, humidity 74-84%, and soil pH 7. This study's results are preliminary data to determine the environmental change around Syamsudin Noor International Airport.

Keanekaragaman Gastropoda Pada Habitat Lamun Di Perairan Desa Tayando Yamtel Kecamatan Tayando Tam Kota Tual

The gastropod community is an important component in the food chain in seagrass beds, where the gastropods are the detritus feeder. Research on the diversity of gastropods in seagrass habitat in the waters of Tayando Yamtel Village, Tam City, Tual District, was conducted in March-May 2018, using the quadrant linear transect method. The results of measurements of environmental parameters in Tayando Yamtel waters are: an average pH of 8.55; DO 6.59 µg / l; salinity 32.36 ‰; temperature of 29 ° C; TDS 24.7 mg / l; current velocity (0.42 m / sec) is classified as low current; and a depth of 1.5 m. Gastropod research results obtained 862 individuals consisting of 15 families and 30 species of gastropods, while for seagrass obtained 3 species namely Cymodocea rotundata, Cymodocea serrulata and Thalassia hemprichii. The highest value of composition and gastropod density at Station I was dominated by Psedeovertagus aluco species at 62.73% and 3.708 (ind / m2), while at Station II were 28.01% and 0.93 (ind / m2) and Station III were 38.46% and 0.15 (ind / m2) are dominated by Strombus gibberulus species. Based on the gastropod ecological index value, the index value of species diversity and harmony is included in the medium category and the index value of dominance is in the low category. 
 
 Keywords: Gastropoda, Seagrass, Tayando Yamtel

Recognition and classification of FBG reflection spectrum under non-uniform field based on support vector machine

Abstract The reflection spectrum characteristics of fiber Bragg grating are very important for its sensing applications. A method of “Feature Extraction-Support Vector Machine (FE-SVM)” to identify spectral types is developed and experimentally demonstrated. The reflection spectrum characteristics of fiber Bragg grating are analyzed and extracted based on theory and simulation calculation. The characteristic data were preprocessed, and the distorted spectrum type recognition model was optimized. Training the data through the network, the recognition accuracy of Support Vector Machine (SVM) network for 1000 groups of FBG mixed spectrum reached 99.9%. To verify the recognition effect of reflection spectrum features, a time-varying temperature field was established as the non-uniform field. The accuracy rate reached 96.875%. The proposed FE-SVM method is characterized by fast response, high reliability and easy optimization, which has a promising application in environmental parameter measurement and substance classification.

Preliminary investigation of lower Danube pollution caused by potentially toxic metals

The current study aims to assess the pollution status of the European river-sea system lower Danube River-Danube Delta-North West Black Sea, through an integrated analysis of metal concentrations in water, sediments and fish community. The Danube flows through numerous industrial cities and receives a significant amount of pollutants due to the reception of urban and industrial emissaries, as well as agricultural land runoff. Samples of water, sediments and fish (10 species) were collected from 7 representative sites along Danube River, Danube Delta and Black Sea shore. For the analysed fish species, potentially toxic and essential elements (Pb, Cd, As, Cu, Fe, Zn, Mg, Ca, Na, K) from muscle and liver samples were measured and discussed. Measurement of elements and other environmental quality parameters were determined for water and sediments. The Black Sea area, represented by S6 and S7, received sediments from Danube with the lowest concentrations of Cd (0.05 ± 0.01 μg g−1, respectively 0.01 ± 0.001 μg g−1), Pb (3 ± 0.03 μg g−1, respectively 2 ± 0.03 μg g−1), As (2 ± 0.02 μg g−1, respectively 1.4 ± 0.3 μg g−1), Ni (8.9 ± 0.1 μg g−1, respectively 5.2 ± 0.2 μg g−1), Cr (8 ± 0.7 μg g−1, respectively 5 ± 0.2 μg g−1), Cu (3 ± 0.1 μg g−1, respectively 2 ± 0.04 μg g−1), Fe(6 ± 0.3 μg g−1, respectively 3 ± 0.1 μg g−1) and Zn (0.03 ± 0.003 μg g−1, respectively 0.017 ± 0.001 μg g−1). These results suggest that the Danube Delta system plays an important role in filtering the pollutants. Based on the biota and water analysis, there was no correlation observed between Cd, respectively Pb concentration in the environment and fish body (Person Coef. = −0.02 in muscle tissue and −0.01 in liver tissue, respectively Pearson Coeff. = −0.06 in muscle tissue and 0.1 in liver tissue). Cadmium remained an active element in the pollution of the Danube area (S1 and S2), with high concentration in the water matrix (0.14 ± 0.02 μg L−1, respectively 0.05 ± 0.01 μg L−1) and fish muscle (0.15 ± 0.03 μg g−1f.w. in C. carpio – S2). This fact was confirmed by several other studies.

Seasonal Variation of Soil Respiration in the Mongolian Oak (Quercus mongolica Fisch. Ex Ledeb.) Forests at the Cool Temperate Zone in Korea

To investigate the variation in seasonal soil respiration (SR) as a function of soil temperature (Ts) and soil water content (SWC) in Mongolian oak (Quercus mongolica) forests in urban (Mt. Nam) and well-reserved (Mt. Jeombong) areas in South Korea, we conducted continuous field measurements of SR and other environmental parameters (Ts and SWC) using an automated chamber system. Overall, the SR rates in both stands were strongly correlated with the Ts variable during all seasons. However, abrupt fluctuations in SR were significantly related to episodic increases in SWC on a short time scale during the growing season. The integrated optimal regression models for SR using Ts at a depth of 5 cm and SWC at a depth of 15 cm yielded the following: the SR rate in Mt. Nam = SR(Ts) + ΔSR(Ts) = 104.87 exp(0.1108Ts) − 10.09(SWC)2 + 604.2(SWC) − 8627.7 for Ts ≥ 0 °C, and the SR rate in Mt. Jeombong = SR(Ts) + ΔSR(Ts) = 95.608 exp(0.1304Ts) − 33.086(SWC)2 + 1949.2(SWC) − 28499 for Ts ≥ 0 °C. In both cases, SR = 0 for Ts < 0 °C. As per these equations, the estimated annual total SRs were 1339.4 g C m−2 for Mt. Nam and 1003.0 g C m−2 for Mt. Jeombong. These values were quite similar to the measured values in field. Our results demonstrate that the improved empirical equation is an effective tool for estimating and predicting SR variability and provide evidence that the SR of Q. mongolica forests in the cool temperate zone of Korean Peninsula depends on Ts and SWC variables.

KELIMPAHAN BINTANG LAUT MAHKOTA DURI (Acanthaster planci L.) DI TELUK TOMINI, SULAWESI TENGAH

This study was aimed to determine the abudance crown of thorn starfish (Acanthaster planci L.) in the Gulf of Tomini, Central Sulawesi. The study was conducted in February─April 2019 preliminary method used a purposive sampling (determining the sampling point for transect sampling) and the belt transect method which is 20 x 2 m. Sampling of A. planci was carried out at 4 stations. Data collected were the number of individuals, measurement of environmental parameters including Temperature, pH, Salinity, DO and Substrate observations on habitat. Based on the results of the study, 48 individuals at all stations and the abundance of A. planci in the Gulf of Tomini, Central Sulawesi were in the natural/normal category with a value of 0.01 ind/m2─0.25 ind/m2.

The Invasive of Freshwater Prawn Macrobrachium lanchesteri (De Man, 1911) from Watershed in Palangkaraya University, Kalimantan, Indonesia

Freshwater prawn species Macrobrachium lanchesteri (De Man, 1911) in Kalimantan for the first time was reported to be found only in East Kalimantan and there have been no reports of this species being found in Central Kalimantan. This study aims to reveal the presence of invasive freshwater prawn and habitat characteristics found in the watershed of Palangka Raya University. This study was conducted in October–November 2019 covering five stations. Specimens were collected using a purposive sampling method. Environmental parameter measurements were made including types of substrate, water velocity, tree cover, water depth as well as width. The identification of specimens from the watershed of Palangka Raya University based on morphological characteristics shown that the species very similar to the alien freshwater prawn, M. lanchesteri. Based on the results of research, this report has revealed the presence of this invasive species in Central Kalimantan, Indonesia.

Machine learning informed predictor importance measures of environmental parameters in maritime optical turbulence

Prediction of the index of refraction structure constant Cn2 in the low-altitude maritime environment is challenging. To improve predictive models, deeper understanding of the relationships between environmental parameters and optical turbulence is required. To that end, a robust data set of Cn2 as well as numerous meteorological parameters were collected over a period of approximately 15 months along the Chesapeake Bay adjacent to the Severn River in Annapolis, Maryland. The goal was to derive new insights into the physical relationships affecting optical turbulence in the near-maritime environment. Using data-driven machine learning feature selection approaches, the relative importance of 12 distinct, measurable environmental parameters was analyzed and evaluated. Random forest nodal purity analysis was the primary machine learning approach to relative importance determination. The relative feature importance results indicated that air temperature and pressure were important parameters in predicting Cn2 in the maritime environment. In addition, the relative importance findings suggest that the air-water temperature difference, temporal hour weight, and time of year, as measured through seasonality, have strong associations with Cn2 and could be included to improve model prediction accuracy.

Experimental Performance Analysis of an Optical Communication Channel over Maritime Environment

Free space optical communications (FSO), which make use of the visible and infrared spectrum for data transmission, offer significant advantages such as a very high data rate, security and immunity, low cost of installation and ease of use without any license restrictions. However, a significant challenge for FSO systems is their inherent constraints due to environmental conditions and especially atmospheric turbulence. This paper focuses on the experimental performance analysis of a real FSO system in a maritime environment. We propose a new model which allows an FSO link performance estimation over sea and depends upon point measurements of environmental parameters. The Received Signal Strength Indicator (RSSI) has been measured and a second-order polynomial has been constructed using regression modeling to quantify its relation with macroscopic environmental parameters collected by a weather station. This model has then been validated against real meteorological data over different period of times and exhibited a reasonably strong correlation. Atmospheric turbulence has been determined using bulk estimates of the structure index parameter extracted from the same meteorological data, and thus allowed for a statistical correlation between turbulence and RSSI. In the second part of the paper, the probability distribution of the RSSI data has been investigated and the Kullback-Leibler (KL) divergence has been used to investigate the difference between probability distributions over the same variable. As an illustrative example of the process, the Weibull, Lognormal and Gamma distributions have been evaluated against the RSSI data probability distribution and the latter has proved to exhibit the best fit.

Greenhouse microclimate environment adaptive control based on a wireless sensor network

Environmental parameter measurements from various sensors spatially distributed in greenhouse crops can be used to create an accurate and detailed depiction of the climate in different regions of the greenhouse. Microclimate environments have an impact on crop yield, productivity, quantitative and qualitative characteristics of plants, and various plant diseases. In this study, an automatic monitoring system based on a wireless sensor network was designed to monitor the survival rate of greenhouse crops. The system design includes a sensor model selection and placement process, host computer monitoring software and communication module design. The Zigbee protocol was used for wireless communication between the nodes. The proposed fuzzy-PID controller was easy to design and highly adaptive to the measurement errors of the sensors. The test results show that the system valuable for monitoring the environment in the greenhouse, where it was successful in controlling and maintaining an optimal microclimate condition. Keywords: greenhouse, microclimate control, wireless sensor network, fuzzy-PID control DOI: 10.25165/j.ijabe.20201303.5027 Citation: Wang L N, Wang B R. Greenhouse microclimate environment adaptive control based on a wireless sensor network. Int J Agric & Biol Eng, 2020; 13(3): 64–69.

Adaptive Thermal Comfort of Elementary School Student (A Case study of the West Coastal Area of South Sulawesi)

This research aims to study the adaptive thermal comfort in elementary school buildings in the west coastal area of South Sulawesi. It was conducted by field survey method to obtain personal data (clothing and metabolic rate) and environmental parameters such as air temperature and humidity, mean radiant temperature (MRT) and the airflow. During the measurements of environmental parameters, the students filled out questionnaires to find out their perceived comfort level by the Thermal Sensation Vote (TSV) and Thermal Comfort Vote (TCV). In addition, respondents are also asked to give an opinion on their desired thermal preference. The results of the environmental parameters measurements were used as references to calculate the Predicted Mean Vote (PMV), Operative Temperature (Top) and Predicted Percentage of Dissatisfied (PPD). The results show that the condition of the elementary school classrooms along the west coast of South Sulawesi are generally in high temperatures. However, most respondents still feel comfortable and able to adapt to these conditions.

A field investigation on the winter thermal comfort of residents in rural houses at different latitudes of northeast severe cold regions, China

The severely cold regions of Northeast have a colder climate and large latitude span in China. Scholars should pay more attention to the creation of a comfortable indoor thermal environment in winter. In order to understand indoor thermal environments and residents’ thermal comfort statuses in areas at different latitudes, a field survey was conducted in three areas: Harbin (45°N), Changchun (43°N) and Shenyang (41°N). On-site environmental parameter measurements and a subjective questionnaire were conducted simultaneously. Then, the relation between operative temperature and building energy consumption was explored. The results showed that the neutral operative temperature is the highest in Harbin (16.8 °C), followed by Changchun (16.4 °C) and Shenyang (16.0 °C), which are all higher than the measured temperatures. For these regions, 90% of the acceptable temperature ranges are 14.6–19.1 °C, 14.4–18.6 °C and 13.9–18.2 °C, respectively. The expected operative temperatures are 18.6 °C, 17.8 °C and 17.3 °C higher than the neutral temperature, respectively. This reveals that as the latitude increases, the neutral temperature, the upper and lower limits of the acceptable range and the expected temperature are all increased. For different ages, the youth have a higher requirement in terms of thermal comfort, followed by the middle-aged and elderly groups. Compare to males, females feel colder under the same operative temperature. Due to the independent heating system in rural houses, adjusting the heat supply, instead of clothing, is the main adaptive behavior. Regarding building energy consumption, as the latitude declines, the influence of changes in operative temperature increases. If both the regional neutral temperature and zoning heating mode are adopted, energy consumption further decreases. These findings provide a reference for the development of an evaluation standard for indoor thermal environments and an energy-saving design for rural houses in the northeast severe cold regions of China.

Climate Adaptive Design Improvement Strategies of Traditional Dwellings in Southern Zhejiang for the Plum Rain Season Considering Comfort Conditions

This study investigated the adaptations of traditional dwellings to the complex regional microclimate in southern Zhejiang, China. Typical traditional dwellings in a village in the foothills and a village on the mid-slopes of Zhejiang’s alpine region were selected to study traditional construction strategies for climate responsiveness and the comfort level of indoor environments during the very humid plum rain season in early summer. Fundamental analysis of the climate and architecture, a response analysis of the dwelling form, an occupants’ comfort satisfaction survey, and field measurements of indoor and outdoor thermal environmental parameters were performed. The traditional dwellings and their design strategies for various regional environmental factors were explored from the perspective of (1) regional climate-adaptive strategies, (2) the thermal, airflow, lighting, and acoustic qualities of the indoor environment, and (3) the occupants’ indoor environment satisfaction. The results indicated that traditional dwellings in southern Zhejiang incorporate strategies of various effectiveness in ensuring indoor comfort.

Adaptive thermal comfort models for homes for older people in Shanghai, China

This research focused on adaptive thermal comfort in homes for older people in the hot summer and cold winter climate zone of China. A field study was conducted throughout the four seasons beginning in January 2014 and ending in April 2017 in Shanghai, China. The survey included simultaneous measurements of outdoor and indoor environmental parameters and an assessment of the participants’ sensations using questionnaires. A total of 19 homes for older people and 64 buildings were surveyed; 1040 measured data points and subjective questionnaires were obtained. The sensation ratings were analyzed, and thermal comfort temperature was calculated using regression methods. Results showed that thermal comfort assessments of older people in Shanghai should use –0.2 < TSV < +0.2 as the standard, yielding acceptable temperature ranges for older people of 14.1–19.4 ℃ in winter, 23.8–27.0 ℃ in summer, and 20.6–31.7 ℃ in mid-season. Adaptive thermal comfort models in different seasons showed that, first, the predictions of the winter and summer models were both reliable. Second, the thermal adaptive models of the mid-season intersected with the ASHRAE 55 model at 20.5 ℃ and was within the applicable range of the mid-season model (10–20.8 ℃); under the same outdoor temperature conditions, the neutral temperatures predicted by the EN15251 model and the ASHRAE 55 model were higher than the predicted values of the mid-season thermal adaptive model. Third, the slopes of both the winter and summer thermal adaptive models were slightly lower than those of the GB/T50785-2012 model. These results can be used to assess indoor thermal comfort in homes for older people and help create age-friendly building environments in China.

Larval fish assemblages in nearshore waters of southeast Gulf of California: vertical and temporal patterns

Abstract The influence of salinity and temperature on larval fish assemblages, as well as, temporal and vertical patterns on larval fish assemblages off the inlet of the Presidio River, southeast coast of the Gulf of California were evaluated. Samplings for ichthyoplankton and environmental parameter measurements were carried out at three depths, in five sampling sites, during September and December 1994, and April and June 1995. Anchovies and herrings (Clupeiformes) were the most abundant larval fish accounting for 77% of the total abundance. A significant relationship between salinity and the abundance of larval herrings (Opisthonema medirastre and O. dovii) and between the water temperature and the abundance of the weakfish (Cynoscion reticulatus) was found. Anchovies (Anchoa lucida, A. walkeri, and A. nasus) were present in all sampled months, while O. medirastre and O. dovii occurred in December and June, and C. reticulatus in September. Larvae of pelagic fish were more abundant near the surface, while larvae of demersal fish were more abundant near the bottom. The present study, by emphasising the importance of considering temporal and vertical changes in larval fish assemblages in coastal environments with ecological and economic importance, will be useful for designing more efficient sampling programs.