DSpace Collection:
http://dspace.cvasu.ac.bd/jspui/handle/123456789/49
2024-03-29T00:30:12ZHABITAT SUITABILITY MAPPING FOR DIFFERENT CULTURE SYSTEMS OF SEAWEED ALONG THE ENTIRE COASTAL AND MARINE TERRITORY OF BANGLADESH: GENERALIZED ADDITIVE MODELLING FOR SPATIAL PREDICTION
http://dspace.cvasu.ac.bd/jspui/handle/123456789/2639
Title: HABITAT SUITABILITY MAPPING FOR DIFFERENT CULTURE SYSTEMS OF SEAWEED ALONG THE ENTIRE COASTAL AND MARINE TERRITORY OF BANGLADESH: GENERALIZED ADDITIVE MODELLING FOR SPATIAL PREDICTION
Authors: Tasnim, Rahanuma
Abstract: Seaweeds are shallow-water, photosynthetic marine macroalgae that have economic
value in the food, cosmetics, pharmaceutical, and biofuel/bioplastics industries as well
as play a significant ecological role in providing food and habitat for organisms.
Although seaweed cultivation is well-advanced in many Asian nations, Bangladesh's
seaweed sector is still in its infancy due to multi-dimensional technological, social,
and environmental challenges, including a lack of a site suitability map along its entire
coastal and marine territorial area. Therefore, we used the Generalized Additive
Model (GAM) to develop habitat suitability mapping for different farming systems of
seaweeds by using the in-situ production data and associated environmental factors of
180 culture plots of four species (Gracilaria sp., Enteromorpha intestinalis, Ulva
lactuca, and Hypnea musciformis) at five culture sites. Besides in situ measurement
data, satellite observations and model simulations were also used to gather the
necessary data. The GAM analysis revealed that seven explanatory variables jointly
explained 78%, 76%, and 79% of the variability in seaweed data from off-bottom
long-line, off-bottom net, and floating long-line culture systems, respectively. The
model also discovered that TSS is the primary driver for the off-bottom net culture
systems and floating long-line system, while salinity is the major driver for the off bottom long-line culture system. The predicted habitat suitability mapping displayed
that the predicted suitable areas (50-100%) for floating long-line culture systems are
significantly larger (1850 km2
) than off-bottom long-line and off-bottom net culture
systems (380 km2
). The highly suitable areas (>75% probability) for off-bottom long line and off-bottom net culture systems are restricted to only the southeast coast, more
specifically for the sandy bottom areas of the Moheshkhali channel and surrounding
areas. The floating long-line culture system is found to be the most suitable for
seaweed farming along the entire coast (except Meghna and adjacent estuaries of the
central region) of Bangladesh. Since Bangladesh is keen to increase the commercial
cultivation of seaweed, this study may provide a crucial tool for achieving the blue
economy goal by providing information on habitat suitability maps along the entire
coastal and marine territory areas of the country.2023-08-01T00:00:00ZMORPHOMETRIC ANALYSIS OF GREEN MUSSELS (Perna viridis) CULTURED AT DIFFERENT WATER DEPTHS IN THE SOUTH EAST COAST OF BANGLADESH
http://dspace.cvasu.ac.bd/jspui/handle/123456789/2638
Title: MORPHOMETRIC ANALYSIS OF GREEN MUSSELS (Perna viridis) CULTURED AT DIFFERENT WATER DEPTHS IN THE SOUTH EAST COAST OF BANGLADESH
Authors: Shanto, Md. Hassibul Hossain
Abstract: Perna viridis is a bivalve native to the Asia-Pacific region including the coastal waters
of Bangladesh. The analysis of the morphometric variations of P. viridis (Green
Mussels) through the truss network method and body shape morphometrics is urgently
needed. This research holds crucial importance for economic benefit and food security,
given its substantial commercial value and potential for cultivation in tropical countries.
Additionally, there's a lack of information concerning its morphometric variations
among populations from distinct locations. A total of 450 samples were taken at three
different depths (1.5 feet, 3 feet, and 4.5 feet) from the three culture sites of Khuruskul,
Chowfaldandi, and Moheshkhali. A total of 150 samples were taken from each location,
with 50 samples each at 1.5 feet, 3 feet, and 4.5 feet in depth. A truss network was
generated with 24 distance variables using digital images of the components and 15
morphometric factors using the SigmaScan Pro software platform. The truss
measurements were transformed before being subjected to factor analysis and a cross validation discriminant analysis. Factor analysis revealed a statistically significant
difference among ten of fourteen morphometric lengths and twenty of twenty-four truss
network measurements for P. viridis at the 0.05, 0.01, and 0.001 levels of significance.
The factor analysis showed that the P. viridis population in these three areas varies
significantly in terms of its morphology. The principal component analysis (PCA)
suggested that the morphometric differences were most significant in Khuruskul and
Moheshkhali than in Chowfaldondi. The morphometric differences were higher in 1.5ft
water depth than 3ft and 4.5ft water depths in each location. To ensure long-term
viability of P. viridis, it is essential to consider these morphological characteristics
when making decisions about management strategies, conservation efforts, and
extensive seed production. Different physical and biological conditions might occur in
the estuaries and the Bay of Bengal, which could help to explain the reason behind such
discrimination among various stocks.2023-08-01T00:00:00ZMultivariate Discrimination of Body Shape Plasticity In The Long Whiskers Catfish (Mystus Gulio) Collected From Different Sources And Salinity Gradient Habitats
http://dspace.cvasu.ac.bd/jspui/handle/123456789/2637
Title: Multivariate Discrimination of Body Shape Plasticity In The Long Whiskers Catfish (Mystus Gulio) Collected From Different Sources And Salinity Gradient Habitats
Authors: Iqbal, Mohammad Zafar
Abstract: The study was carried out to investigate the body shape variation of the Mystus gulio
collected from three different salinity gradient habitats (high-salinity brackish water, low salinity brackish water, and freshwater) and two different sources (wild and hatchery) using
traditional morphometrics (linear and truss-networking distances) and landmark-based
geometric morphometrics. A total of 436 individuals of M. gulio were collected from the
high-salinity (8-15 ppt), low-salinity (2-6 ppt), and freshwater bodies (0 ppt). For wild
versus hatchery sources body shape variation, 430 individuals of M. gulio were collected
from various coastal rivers and hatcheries. M. gulio from different salinity gradient habitats
and sources exhibited negligible sexual dimorphism. Principal component analysis (PCA)
indicated that high and low salinity populations appeared to form overlapping clusters with
the freshwater populations, but other multivariate analyses discriminated both populations
from brackishwater habitats from the freshwater counterparts. The geometric morphometrics
displayed that the body shape variation of M. gulio from salinity gradient habitats was
mainly visible in the width of the dorsal-ventral part, the snout shape, the tail shape, the head
region and the eye diameter. PCA demonstrated that multivariate spaces of both the wild and
captive populations overlapped each other, although many individuals of the wild population
were discriminated from the culture populations. Our results showed that traditional and
geometric morphometric methods provide consistent outcomes for body shape
discrimination in the M. gulio populations2023-06-01T00:00:00ZSTUDY ON THE MORPHOMETRIC TRAITS AND BREEDING BIOLOGY OF Meretrix meretrix COLLECTED FROM MOHESHKHALI CHANNEL, COX’S BAZAR, BANGLADESH
http://dspace.cvasu.ac.bd/jspui/handle/123456789/2636
Title: STUDY ON THE MORPHOMETRIC TRAITS AND BREEDING BIOLOGY OF Meretrix meretrix COLLECTED FROM MOHESHKHALI CHANNEL, COX’S BAZAR, BANGLADESH
Authors: Lima
Abstract: The potential local and international markets, suitable habitats and by-product use has made
the Asian hard shell clam, Meretrix meretrix as one of the potential species that may enhance
the blue economy of Bangladesh. The fundamental aspects of reproductive biology,
biometric, and morphometric traits for this genus in the coastal waters of Bangladesh remain
unexplored. Therefore, this study was conducted to delineate the morphometric traits and
breeding biology, including the Gonadosomatic Index (GSI) and Condition Index (CI), of
Asian hard clam M. meretrix. A total of 2267 samples were collected from Chowfaldandi
canal, near the Moheskhali Channel, over a year (from December, 2021 to November, 2022)
during full-moon cycle at low tide. The positive correlations were observed between shell
length- total weight, shell height- total weight-shell-width (p< 0.001). These relationships
suggested that specific morphometric traits were linked to clam growth patterns, where
allometric growth patterns were observed (W= 0.046* L
1.63, b=2.021). The sex ratio male to
female for this species was 1:1.66 (P > 0.001) determined through Welch F test. The
gametogenesis cycles was observed through histology showed that spawning periods for
males were from February to April 2022, and for females from March to May 2022.The
gametogenesis cycles of male and female M. meretrix exhibited stages of development and
maturation, with males showing a tendency to initiate gametogenesis earlier than females.
GSI value reached its peak in November-December indicating initiation of spawning period
and reached its lowest point in June-July, signifying a period of inactivity or rest. The highest
condition index value was noted in March 2022 (5.44±2.05), while the lowest was recorded
in May,2022(2.16±1.31). Interestingly a high CI value in July despite being associated with
the resting phase, emphasizing that CI values are influenced by factors beyond reproductive
changes, such as water parameters and environmental conditions. Overall, this
comprehensive study sheds light on the morphometric traits, breeding biology, and
reproductive cycles of Meretrix meretrix providing valuable insights into its life history and
potential reproductive periods2023-08-01T00:00:00Z