Dhaka University Journal of Biological Sciences

Editor's Note

Prof. Dr. Mihir Lal Saha

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ICHTHYODIVERSITY OF A SMALL COASTAL RIVER IN BANGLADESH

MAKIDUL ISLAM KHAN

Small rivers are often ignored in terms of conservation actions and biodiversity
management in Bangladesh. Despite having significant ecological and economic
importance of these rivers, there is limited study done so far. To partially fulfill
this gap, this study aimed to assess the fish and shellfish biodiversity of a small
coastal river named Tiakhali from southern Bangladesh. A total of 26 finfish and
7 shellfish species were identified where 50% of finfish and all of the shellfish
species were from the order Perciformes and Decapoda, respectively. Results
showed that 76.9% of finfish and all of the shellfish species were categorized
into the least concern category based on IUCN Red List. Estimated Shannon’s,
Margalef’s, Buzas & Gibson’s and Simpson’s indices were 1.189, 2.649, 0.435 and
0.435 for fish and 1.662, 0.758, 0.224 and 0.224 for shellfish, respectively. This study
showed that Tiakhali river’s fish biodiversity was comparatively smaller than big
rivers. The findings of this study might serve as a baseline for future works and
will help policymakers to pay attention to conserve such small rivers and their
biodiversity in future.

NEW RECORD OF SLIPPER LOBSTER THENUS INDICUS LEACH, 1816 (CRUSTACEA: DECAPODA: SCYLLARIDAE) FROM BANGLADESH WATERS

MD. SAGIR AHMED

Slipper lobster Thenus indicus Leach, 1816 (Crustacea: Decapoda: Scyllaridae)
has been recorded for the first time from Cox’s Bazar coast of the Bay of Bengal.
The species was taxonomically identified by using the traditional morphometric
method which was further validated by molecular approach based on partial
cytochrome c oxidase subunit I (COI) and 16S rRNA gene sequences (DNA
barcodes). The key characteristics of this species are spotless pereiopods, 1st
pereiopod merus width less than 7% of carapace length, and 3rd pereiopod merus
length more than 45% of carapace length.

A BRIEF ACCOUNT ON PROTOZOAN INFECTION IN ASIAN STINGING CATFISH, HETEROPNEUSTES FOSSILIS (BLOCH, 1794) IN DIFFERENT SEASONS OF BANGLADESH

ZANNATUN NAHAR JHINU

The study was conducted to identify the protozoan parasites in a freshwater
indigenous air breathing fish, Heteropneustes fossilis (Bloch, 1794). The host fish was
collected during mid of the April 2018 to end of the March 2019 from freshwater
bodies of Mymensingh, Kishoregonj, Faridpur, Jashore, Manikganj and Bogura
districts of Bangladesh. Three species of phylum myxozoa namely Henneguya
singhi, Henneguya qadrii, Henneguya mystusia, one species of phylum ciliophora
namely Trichodina siddiquae and two species of phylum mastigophora namely
Trypanosoma singhii and Piscinoodium pillulare were identified in H. fossilis. The
parasites of all infected hostswere observed in gill, body slime and blood, however
gillswere commonly infected by parasites rather than body slime and blood. Three
species of parasite Piscinoodium pillulare, Henneguya qadrii and Henneguya mystusia
were first recorded in this host fish and novel locality record in Bangladesh. H.
fossilis was found to be infected over the three major (p<0.05) (summer, rainy and
winter) seasons and demonstrated a strong significant association (P0<05) with
season during the study period. In H. fossilis, highest variety and highest number
of parasites were found in winter season, prevalence and intensity was found
78.31% and 5.17 respectively. Lowest prevalence and intensity were found in rainy
season respectively 45.87 and 4.72. Among all the parasites Henneguya singhi was
common in all the three seasons and its rate of infection was found elevated in
summer (20.69%) and rainy season (19.27%). In H. fossilis prevalence of female fish
were highest in all the three seasons, summer (55.22%), rainy (50.75%) and winter
(85.57%) than their male counterparts 38.76%, 38.09% and 68.12%, respectively.

IMPACTS OF MARINE FISHING BAN ON THE ECOLOGY OF HILSA IN THE NIJHUM DWIP SEASCAPE IN BANGLADESH

MAKIDUL ISLAM KHAN

Bangladesh government has imposed a 65-day marine fishing ban since 2015 to
conserve marine fisheries, particularly to boost hilsa (Tenualosa ilisha) production.
However, the ecological impacts of the marine fishing bans on water quality
and hilsa’s growth are not assessed yet. Thus, this study aims to contribute here
using data from coastal waters and fish from pre-contacted fishers in the Nijhum
Dwip seascape during and outside the fishing ban in 2021 – 2022. Data were
analyzed using R software. The measured mean dissolved oxygen, temperature,
pH, electrical conductivity, total dissolved solids, and transparency of the sample
water were 7.1 ± 1.13 mg/l, 31.1 ± 0.71°C, 8.45 ± 0.07, 40000 ± 2828 μS/cm, 18000 ±
1414 mg/L and 63.5 ± 2.12 cm at 1 week prior to the ban ends (July) and 8.45 ± 0.21
mg/l, 22.35 ± 0.49°C, 8.45 ± 0.07, 20500 ± 1060.66 μS/cm, 10350 ± 212.13 mg/l and
63.5 ± 7.78 cm before the ban starts (February). The values might be varied due to
seasonal differences. The mean length (38 cm) and weight (601 g) of sampled hilsa
during the ban periodwere comparatively larger than the mean length (29 cm) and
weight (229 g) of hilsa which were sampled during the outside fishing ban period.
Therefore, this study concludes that the marine fishing ban has positive impact on
the growth and size of hilsa. This study suggests that further research is required
to assess the fishing ban’s impact on the growth and production of other coastal
and marine fish species across the Bay of Bengal.

IMPACT OF COVID-19 ON MENTAL HEALTH OF DHAKA UNIVERSITY STUDENTS

MD. REZA-A-RABBY

Student mental health in the university setting has been an expanding concern.
The COVID-19 pandemic could be detrimental to the psychological wellness of
university students. The aim of this investigation was to see the mental health
outcomes of Dhaka University students during the COVID-19 outbreak. A crosssectional
survey using a convenient sampling technique was conducted among
193 students of the University of Dhaka within a time duration of 1 month. Data
was gathered by utilizing the web survey including DASS-21BV, demographic
questions, and health-related queries with respect to COVID-19. The prevalence of
anxiety symptoms and depressive symptoms was 64.2 % and 66.9%, respectively,
and 51.8% of students reported mild to extremely severe levels of stress. Age
group was significantly associated with DASS-21 depression subscale scores (χ2
(2)> =14.179, p= .007). Hall status was also significantly associated with DASS-21
anxiety subscale scores (χ2 (2)> =10.001, p= .040). Sleep-related queries with respect
to COVID-19 were significantly associated with DASS-21 anxiety subscale scores
(χ2 (2)> =24.135, p= .002). COVID-19-related queries on attention, enthusiasm,
mental state, and self-confidencewere also significantly associated with depressive
symptoms, anxiety symptoms, and stress levels (p<.001). The COVID-19 outbreak
seems to have had a considerable psychological impact on Dhaka University
students and would be benefited greatly through adequate support from the
relevant authorities to cope with the situation mentally.

THE RELATIONSHIP BETWEEN AUTONOMY AND COGNITIVE EMOTION REGULATION AMONG ADOLESCENTS

ANTARA DAS ANTU

Autonomy and cognitive emotion regulation both are important aspects of
adolescent years. Previous research also indicates that an individual’s cognitive
emotion regulation (CER) and autonomy is correlated. The present study aimed
to gain more insight into the relationship between autonomy and cognitive
emotion regulation of Bangladeshi adolescents. Cross sectional survey design was
used covering 100 adolescents having an age range of 12-15 years of age for data
collection. Participants completed the questionnaires including a demographic
questionnaire, adolescent autonomy questionnaire and cognitive emotion
regulation questionnaire. Correlation analysis suggests that autonomy support
showed an increase in the adaptive emotion regulation. Regression analysis
models revealed that adolescent autonomy significantly explained 14.6% of
variance for adaptive emotion regulation, and 4.6% of variance for less adaptive
emotion regulation. Findings from the present study embodied that Bangladeshi
adolescents use more adaptive cognitive regulation than maladaptive emotion
regulation. These findings have implications for parents, primary caregivers, child
psychologists, and other relevant professionals who are and will be working with
children/ adolescents in helping them to learn and enhance their autonomy for
their future and effective cognitive regulation of emotion.

ISOLATION OF BIOTECHNOLOGICALLY IMPORTANT ENZYME PRODUCING RHIZOBACTERIA FROM SEASONAL FLOWER BEDS

RAHANA YEASMIN

This study aimed to isolate biotechnologically important enzyme like amylase
and protease producing rhizobacteria from rhizospheric soil. Soil samples were
collected from the rhizospherc of five different flowering plants from Curzon hall,
University of Dhaka. A good number of bacteria were isolated. Among them 12
bacterial isolates were selected for detailed study based on their amylolytic and
proteolytic activity. Starch hydrolysis ratio (SHR) of the studied isolates ranged in
between 2.06 and 4.67, casein hydrolysis ratio (CHR) ranged in between 2.27 and
3.92. All the selected isolateswere Gram positive and rod shaped and provisionally
identified as the member of the genus Bacillus with five different species viz. Bacillus
alcalophilus, B. subtilis, B. pumilus, B. firmus and B. lentus. Amylase and protease
production of the studied bacteria were estimated and it was ranged in between
29.11±9.57 to 35.78 ± 9.05 and 230.27±37.08 to 276.47 ± 55.01 U/ml. The highest
amylase and protease producer were Bacillus alcalophilus (Ce104/S9/L) which could
produce 35.78 ± 9.05 U/ml and Bacillus subtilis (Ca71/S5/L) could produce 276.47
± 55.01 U/ml of protease, respectively. Maximum production of both amylase and
protease was achieved in 24 h of incubation period at 37°C and pH 7.0.

ACCUMULATION OF NITROGEN, PHOSPHORUS, POTASSIUM AND SULFUR IN CAPSICUM (CAPSICUM ANNUUM L.) AS INFLUENCED BY VERMICOMPOST AND NPK FERTILIZERS

MAHBUB HASAN TALUKDER

Soil fertility is one of the most promising factors that directly impact
sustainable crop production. Therefore, a pot experiment was conducted in net
house on capsicum (Capsicum annuum L.) in the agricultural soil to study the
effects of vermicompost (VC) and inorganic fertilizers (NPK) on growth, yield and
nutrient content in capsicum plants. The growth parameters and nutritional values
were observed during the experiment under eleven treatments. The treatments
variables are T1 (control, -VC & -NPK), T2 (VC 5 ton/ha), T3 (VC 10 ton/ha), T4 (VC
15 ton/ha), T5 (N60P35K60 kg/ha), T6 (VC 5 ton/ha +N48P28K48 kg/ha), T7 (VC 10 ton/ha +
N48P28K48 kg/ha), T8 (VC 15 ton/ha + N48P28K48 kg/ha), T9 (VC 5 ton/ha + N36P21K36 kg/
ha), T10 (VC 10 ton/ha + N36P21K36 kg/ha), T11 (VC 15 ton/ha + N36P21K36 kg/ha) which
were arranged in a completely randomized design (CRD) with three replications.
There were statistically significant differences in each treatment for growth and
yield parameters. The highest plant height (45 cm), the highest number of leaves
(44 no/plant), and the highest leaf area index (90 cm2) were found in the treatments
T6, T5 and T9 respectively. The lowest values for all of the above parameters were
found in the treatment T1 (control). Then the highest yield parameters fruit no/
plant (3), total fresh weight (39.60 g/plant), and total dry weight (2.38 g/plant) were
observed under the treatment T11. The results of the growth and yield parameters
varied significantly (p<0.05). The concentrations of total N, P, K and S in different
parts were measured and varied significantly (p<0.05) in leaf, stem, root and seeds.
Analysis of post-harvest soil also revealed that every physico-chemical property
and nutritional value were changed significantly due to different treatments.

GROWTH AND YIELD PERFORMANCE OF SUNFLOWER (HELIANTHUS ANNUUS L.) AS INFLUENCED BY COW DUNG AND NPK FERTILIZERS

MD. ALAUDDIN

A field experiment was conducted at the research farm of Charfasson Govt.
College, Bhola, Bangladesh in rabi season in 2015-2016 to evaluate the effect of
cow dung and chemical fertilizers on growth and yield of sunflower cv. BARI-2
(Keroni-2). Highest plant height (208.4 cm), leaf area (410.5 cm2) and leaf area
index (12.75) were recorded in T16 (7.5 ton CD ha-1 +N120P90K150kg ha-1). Highest
dry matter yield viz. stem (60.67g plant-1) found in treatment T16 (7.5 ton CD ha-
1+N120 P90K150kg ha-1). Maximum dry weight of leaf (25.33g plant-1) and dry weight
of root (12.83g plant-1) were found in treatment T15 (7.5 ton CD ha-1 +N80P60K100kg
ha-1). Highest dry weight of seed (64.7 g plant-1) and dry wt. of 100 seed (9.8 g)
were found in treatment T15 (7.5 ton CD ha-1 +N80P60K100kg ha-1) but the highest
number of seed (735.7plant-1) and florescence diameter (52.67 cm) were observed
in treatment T13 (5 ton CD ha-1 +N120P90K150kg ha-1). Maximum total dry matter yield
per plant was 92.01 g and per hectare was 5.75 ton in T16 (7.5 ton CD ha-1+N120
P90K150kg ha-1). Results revealed that the combined application of cow dung and
NPK fertilizers produced better growth and yield of sunflower in field condition
at the coastal belt of Bangladesh.

INFLUENCE OF LAND TYPE AND CROPPING ON THE DISTRIBUTION OF MICRONUTRIENTS IN GANGES RIVER FLOODPLAIN SOILS OF BANGLADESH

MUHAMMAD SAJIDUR RAHMAN

The soils of Ganges River Floodplain (GRFP), an important crop growing zone
of the country, are known to be widely deficient in micronutrients. The study was
conducted to relate the distribution and the fate of soil micronutrients in relation
to land type, soil properties and cropping practices in GRFP.A total of 52 locations
were selected for sample collection from across GRFP, varied in land type, soil series
and cropping pattern, and analysed for DTPA extractable iron (Fe), manganese
(Mn), copper (Cu), zinc (Zn) and hot water soluble boron (B). Most of the samples
were found deficient in Zn and B, while a moderate number of samples were Fedeficient.
The major reason of micronutrient deficiency was found to be high soil
pH. Among the four soil series studied, Ghior series was most deficient in Zn and
B, implying pedogenic differences among the soils. Significant effect of contrasting
land types on the distribution of soil micronutrients was observed although the
effect was not consistent. The rice-rice cropping pattern was found to have slightly
higher contents of Mn, Zn and B compared to rice-non-rice pattern which might be
due to longer submergence period in the soils under rice-rice pattern.

MAGNITUDES OF BASIC SLAG ON IRON DYNAMICS IN TWO ACID SULFATE SOILS DURING 30-MONTHS OF INCUBATION UNDER VARIOUS MOISTURE REGIM

MD. HARUNOR RASHID KHAN

The magnitudes of basic slag (BS) at 0, 10, 20 and 30 t ha-1 on iron dynamics in
two acid sulfate soils (ASSs) under moisture at field capacity, saturated condition
and wetting-drying cycle were studied during 30 months of incubation (25-30
0C). The impacts of BS in Sarisabari ASS were almost similar as those obtained
in Purbapukuria ASS under various treatments, but the increments of pHs in
Sarisabari ASS were not as pronounced as those observed in Purbapukuria ASS. The
pH valueswere increased by about 1.0, 1.5 and 1.2 units in Sarisabari and 2.0, 1.7 and
1.5 in Purbapukuria ASSs, those received BS30 at field capacity, saturated condition
and wetting-drying cycle, respectively and followed by BS20 > BS10 treatments. The
contents of basic cations in the studiedASSswere low to medium, while acidic cations
were very high in relation to the amounts found in the ASSs elsewhere. Magnesium
contents were about 2 to 3 -folds than those of Ca but Fe contents were very high.
The application of basic slag in the ASSs was found to reduce the acidity problems
noticeably and decreased the Fe contents remarkably. Neutralization of acidity by
BS30 at saturation moisture level was determined to be the best for both the ASSs
followed by moisture at field capacity and wetting-drying cycle. The soil pH was
found to have strong positive relationship with time, while the Fe contents showed
strong negative relationship with the corresponding pHs of the ASSs. These indicate
that the amelioration of ASSs by the application of BS is a sustainable reclamation
and improvement measures regarding Fe toxicity of the soils.

INTEGRATED EFFECTS OF VERMICOMPOST, CLIMATIC FACTORS AND SOIL MIXING ON SELECTED SOIL FERTILITY INDICATORS

MITHUN KUMAR SAHA

A field experiment was carried out to investigate the effects of vermicompost
(0, 10, and 15 tha-1), climatic elements i.e. soil moisture (50%, 70%, and 100%)
and elevation of soil temperature (1 to 20C) on the physico-chemical properties
and nutrient availability of post-harvest calcareous-acid mixed soils after rice
production. A total of 18 treatments assembling the afore-mentioned doses was
applied. The analyses of the soils demonstrated significant variation in effects
(p ≤0.05) of the treatments on both the available nutrient status and the physicochemical
properties of soils. Except for available sulfur; soil pH, EC, organic carbon
(OC), available nitrogen, phosphorous, potassium, calcium, and sodium were
detected in the higher amounts in 1:1 (calcareous : acid-soils) mixed soils than
those of 1:3 mixed counterpart both in initial and post-harvest soil conditions. The
highest levels of soil pH, OC, available P and Zn were determined in the treatment
T13. Whereas, treatment T6 proved to be the best dose for the highest availability of
Ca and Mg. The treatments T1, T2, T11, and T16 were recorded to have the lower OC,
available N, P, Ca, Mg, Zn and S contents in soils. In particular, the availability
of Na was found to be in lesser amounts in all the subplots. In a nutshell, most of
the treatments exerted favourable influence in maintaining a healthy level of soil
physico-chemical parameters owing to their inherent characteristics.