Search

The present study investigated the effects of different dietary protein levels on the growth and survival of milkfish Chanos chanos for 90 days feeding trial. Milkfish with an average body weight of 10.81 ± 0.07 g were collected from the coastal zone using a manual dragnet. The study tested four diets, 10% (T1), 15% (T2), 30% (T3) and 38% (T4) of proteins containing feed with triplicates. These diets were offered to the milkfish juveniles in triplicate earthen ponds (1.5 ha). Juveniles were stocked at 10,000 ind./1.5 ha, and initially feeding rate of 10% biomass per day. The feeding rate adjusted according to fish biomass on a weekly basis. The present results showed that fishes fed 30% of proteins-containing feed have the highest weight gain (WG), specific growth rate (SGR), average daily weight gain (ADWG), survival, and the best feed conversion ratio (FCR) compared to the other treatments. The present study suggested that 30% crude protein is the optimum level for the best growth performance and for obtaining a high yield of milkfish C. chanos reared in the brackish water ponds.

Countries around the world have already been experiencing the repercussions of climate change. Bangladesh is cited as one of the most vulnerable countries among them. Due to the utmost contribution to the country’s economy and continuous exposure to climatic extremes, climate change scenarios for the largest division in the country, the Chittagong Division, have a major concern. This study analyzed the potential climatic changes by the downscaling approach for the Chittagong Division under Representative Concentration Pathways (RCPs) i.e., RCP 2.5, RCP 4.5 and RCP 8.5, and Special Report on Emission Scenarios (SRES) i.e., A2, A1B, and B2 scenarios. Statistical Downscaling Model (SDSM) was used for downscaling three General Circulation Models (GCMs) viz. HadCM3, CanESM2, and CGCM3. A quantitative approach was used for both calibration and validation, where the results indicated the suitability of SDSM for downscaling daily mean temperature and precipitation under different scenarios for three future time horizons, i.e., early-twenty-first, mid-twenty-first, and late-twenty-first century. Additionally, bias correction was applied to downscaled climate variables. The downscaled projection showed increasing trends in mean annual temperature and precipitation for all the scenarios by the end of the century. Under CanESM2, the highest increase in temperature and precipitation were projected as 1.1 °C and 1.7 mm for the RCP 8.5. On the other hand, the highest increase in temperature and precipitation were projected as 0.5 °C and 1.4 mm for the SRES scenario A2 under CGCM3 and HadCM3. The spatial distribution of projections shows that the southern coastal part of the division is marked by remarkable future changes. The downscaled pathways have set a basis for assessing the impacts of future climate change on different sectors for the Chittagong Division and other areas in the country.

Sediment samples were collected from ten selected sites of the lower Meghna River estuary, and six heavy metals were analyzed with Atomic Absorption Spectrophotometry (AAS) to assess the contamination level and the metals’ association with sediment grain size. The current results revealed that the mean concentrations of the studied metals were ranked in descending order of iron (Fe) (1.29 × 103 mg/kg) > zinc (Zn) (42.41 mg/kg) > lead (Pb) (12.48 mg/kg) > chromium (Cr) (10.59 mg/kg) > copper (Cu) (6.22 mg/kg) > cadmium (Cd) (0.28 mg/kg). The geo-accumulation, contamination, and pollution load indexes suggested that the lower Meghna river estuary was not contaminated by Fe, Zn, Pb, Cr, and Cu. The mean size of the sediment ranged from 28.92 to 126.2 μm, and the Pearson correlation coefficient showed a significant association between Fe and Pb (coefficient of determination, r2 = 0.836; p

The scarcity of arsenic and iron-free safe drinking water is an alarming issue in the southern part of the Bengal Basin. The objectives of the present study were to investigate the spatial distribution of manganese (Mn) concentration in the shallow and deep groundwater and its associated health risks for the children and adults of entire southern Bengal Basin. The Mn concentration in the groundwater varied from 0 to 5.4 mg/L with an average value of 0.47 mg/L that exceeded the WHO’s and Bangladesh drinking water guideline values of 0.4 and 0.1 mg/L, respectively. Mn concentration in the shallow wells overrode the deep ones. About 23% of the shallow wells and 11% of deep wells exceeded the WHO’s safety limit of Mn concentration for human health. The human health risk related to Mn contamination was estimated by computing the average daily dosage (ADD) and hazard quotient (HQ) values for children and adults. The average computed HQ values found 0.108 and 0.099 for children and adults, respectively. The HQ values delimitated that children are posing a higher risk compared to the adults for the shallow wells. Deep wells were found risk-free for both children and adults. The areal coverage of shallow wells with HQ values > 1 was minimal compared to the total study area and covered only a small portion of Patuakhali and Barguna districts. The rest of the site does not pose any health risk due to Mn contamination for children and adults.

Seaweeds can play an essential role in controlling antibiotic resistance for bacterial diseases. Three extracts of two brown seaweeds Padina tetrastromatica and Sargassum ilicifolium were investigated as growth promoters and to provide immune protection against Vibrio parahaemolyticus. Extracts of the two seaweeds were administered at 2.5 and 5 g kg−1 with food for 45 days to Penaeus monodon juveniles. The maximum weight gain (6.28 and 7.08 g), specific growth rate (3.39 and 3.32%), and survival rate (78.45 and 82.45%) of the juvenile tiger shrimp were obtained at a dose of 5 g kg−1 with P. tetrastromatica extracted by methanol and ethanol, respectively; which was significantly higher than the other solvents and control group (p .05). However, the administration of 5 g kg−1 methanol and ethanol extract of P. tetrastromatica improved growth performance and the immune capacity of P. monodon by increasing their phenoloxidase activity, superoxide anion concentration, and resistance against V. parahaemolyticus.HIGHLIGHTS The maximum growth performance and survival of juvenile tiger shrimps obtained with Padina tetrastromatica extract at a dose of 5 g kg−1. The methanol extract of P. tetrastromatica and Sargassum ilicifolium had maximal antibacterial activity against V. parahaemolyticus. The administration of 5 g kg−1 methanol and ethanol extract of P. tetrastromatica improved growth performance and the immune capacity of P. monodon.

This study was carried out to evaluate the population growth and egg ratio of Brachionus rotundiformis by feeding with three different diets, i.e., live microalgae Nannochloropsis sp., Baker’s yeast, and powdered spirulina. A total of nine conical flasks of 1 L volume were divided into three treatment groups for determining the feeding performance for eight consecutive days. Each experimental group was stocked with B. rotundiformis at an initial density of 10 ind. mL−1. Water temperature, pH, salinity, and light were maintained at (24–29) °C, (7.5–8.5), 30 ppt, and 4000 lx, respectively. Feed was provided twice per day at 9:00 AM and 7:00 PM. The highest mean (±SE) population growth of rotifer was achieved at the end of the culture period (on the 8th day) fed live Nannochloropsis sp. (122 ± 12 ind. mL−1), which was significantly higher compared to the Baker’s yeast and powdered spirulina (p 0.05). The highest mean (±SE) egg ratio of B. rotundiformis was observed in the live Nannochloropsis fed group (0.89 ± 0.01) at the end of the rearing period, which was significantly higher than that of Baker’s Yeast and powdered Spirulina fed group (p

Size frequency, length-weight relationships (LWRs), and length-length relationships (LLRs) for an estuarine fish Taenioides cirratus (Blyth, 1860) from the Noakhali coast, Bay of Bengal was studied. Specimens were caught with the fixed purse net of two mesh sizes (0.2 to 0.5 in. and 2.0 to 2.5 in.) from March to July 2019. The maximum total length for male T. cirratus (36.2 cm) reported in this study is a new record for this species. The length-weight relationships for male, female, and unsexed T. cirratus was highly significant (p

Size frequency, length-weight relationships (LWRs), length-length relationships (LLRs), and relative condition factor (Kn) was studied in an estuarine fish the Bengal yellowfin seabream, Acanthopagrus longispinnis (Val.), from Hatiya Island in the Meghna River estuary. Specimens were caught with fixed purse nets of two mesh sizes (0.2 to 0.5 inch and 2.0 to 2.5 inch) from January to March 2020. The total body length of A. longispinnis ranged between 5.8 and 9.3 cm throughout the sampling period. The length-weight relationships for A. longispinnis was highly significant (p < .001), and the adjusted r 2 value was 0.921. The calculated growth coefficient (b) for A. longispinnis was 3.163, which indicated a hyperallometric growth pattern. The length-length equation TL = 1.1384 SL + 0.4899 for unsexed A. longispinnis was highly significant (p = 0.001, r2 = 0.951). There were no significant variations in relative condition factors among the specimens of different length classes (5.5–9.5 cm). No information regarding length-weight or length-length relationships for A. longispinnis was previously reported in FishBase. Our estimated LWR and LLR parameters for A. longispinnis can be useful for management and conservation purposes of this estuarine species.

The present study was designed to assess the alternate environmental friendly source of protein; here we report the suitability of soybean meal as a plant protein source for partial replacement of fishmeal in the diet of Arabian yellowfin seabream Acanthopagrus arabicus; reared in floating net cages. A total of 56 days feeding trial was conducted to evaluate the growth performance, feed utilization, survival, and carcass composition of the juveniles. Triplicate groups (30 fish/cage) of A. arabicus (initial weight 22.61 ± 0.11 g) were stocked in floating net cages (1.5 × 1.5 × 1.5 m). Five semi-purified experimental diets, each containing 42% dietary protein, were prepared where fishmeal was replaced with soybean meal: 0% (control), 20% (SBM20), 40% (SBM40), 60% (SBM60) and 80% (SBM80). Fish were fed twice daily at 7% body weight. The formulated diet was well accepted by the fish, where, 100% of survival was recorded at the end of the experiment. No significant differences (P > 0.05) were observed in final weight gain (WG) and specific growth rate (SGR) of juvenile Arabian yellowfin seabream fed on SBM20 and SBM40 diets compared to the control diet. However, a decline in growth performance was recorded in fish received SBM60 and SBM80 diets. Poor feed conversion ratio (FCR) was observed for fish fed with increasing dietary soybean meal above SBM40. No significant differences (P > 0.05) were found in the final whole-body carcass composition of proteins, moisture, and ash. However, the lipid content in the fish body increased significantly (P

Rainbow trout

Hilsa shad is one of the most important fisheries, contributing about 12.9% of the country's (Bangladesh) total fish production. There was no previous study on microplastic contamination of this important commercial fish. This study aims to identify, classify, and quantify microplastics (MPs) ingested by the national fish of Bangladesh, Hilsa shad, Tenualosa ilisha. A total of 287 MPs were recovered from the gastrointestinal tracts. All the fishes analyzed were contaminated with MPs. The mean (±SD) of the number of MPs was 19.13 ± 10.77 particles/fish, ranging from 7 to 51 particles/fish. Significant correlation was not found between the fish body length and MP abundance (rs = 0.287, p = 0.299), and between the fish body weight and MPs abundance (rs = 0.261, p = 0.347). The most dominant color was transparent (30%), followed by gray and black, contributing to 26% and 23%, respectively. The maximum number of MPs accounted for in the 300-1500 μm size class where fiber was the most dominant (50%) shape of observed MPs. These results provide a baseline of MP contamination in seafood from Bangladesh that should be useful for future monitoring efforts. The present study is the first research on MP contamination of Hilsa shad.

Ten surficial sediment samples (up to a depth of 3 cm) were randomly collected during the pre-monsoon and analyzed for nine heavy metals using an atomic absorption spectrophotometer (AAS) to assess the distribution, contamination levels, and potential sources of heavy metals. The particle size distribution of the sediments was also investigated using a laser particle size analyzer. The mean concentration (mg/kg) of the analyzed metals followed a decreasing order of Fe (4706.24) Mn (95.20) Cu (36.97) Zn (20.65) Ni (9.26) Cr (7.20) Pb (5.63) Co (5.52) Cd (0.29). Surficial sediment of the Island was low to moderately contaminated by Cd and, to a laser extent by Cu in terms of enrichment factor (EF), geo-accumulation index (Igeo), and contamination factor. Ecologically, the Nijhum Dweep area was at low to moderate risk, where Cd was the most potential ecological risk factor. The Pearson correlation analysis revealed a significant positive correlation among Cr, Pb, Zn, Mn, Cd, Fe, Co, Ni, and silt particles, whereas a negative correlation with sand particles. No correlation was found with Cu and other metals except clay particles.

The current study aimed to evaluate the distribution and status of heavy metal contamination of surface water in the Nijhum Dweep, northern Bay of Bengal. Ten surface water samples were collected to determine the heavy metals and the associated human health risk. The mean concentrations of the selected heavy metals were ranked in descending order of Fe (3.412 mg/L) > Mn (0.3911 mg/L) > Pb (0.3 mg/L) > Co (0.2918 mg/L) > Zn (0.230 mg/L) > Ni (0.1943 mg/L) > Cu (0.167 mg/L) > Cd (0.11 mg/L) > Cr (0.077 mg/L). All the metals except Cd, Pb, and Ni were found uncontaminated, and these three metals influenced the values of heavy metal pollution indices. Heavy metal evaluation index (HEI), heavy metal pollution index (HPI), and Nemerow pollution index (NI) revealed that the surface water of the study area is low to moderately contaminated by these selected heavy metals. Hazard quotient (HQ) and hazard index (HI) for adults and children showed no non-carcinogenic risk of heavy metals from dermal exposure pathways except station number 4 at the south of the Nijhum Dweep due to high Mn concentration. No possible carcinogenic risk was found from the analyzed metals. Several local sources of heavy metals were found during the field investigation, such as domestic effluents, small-scale metallurgical activities, oil spills from ships, and fishing trawlers. Again, industrial effluents and agrochemicals from upstream regions also contribute to heavy metal pollutions in downstream coastal regions of Bangladesh. Even though the surface water pollution level is low in the study area, the authority should take proper management and monitoring strategy for sustainability.

The present study aimed to assess the levels of heavy metals and metalloids present in six seaweeds and their potential impact on consumption. The highest concentration of 11 metals, i.e., Be (0.47 mg/kg), Co (4.34 mg/kg), Cr (23.46 mg/kg), Cu (11.96 mg/kg), Fe (2290.26 mg/kg), Li (11.55 mg/kg), Ni (13.75 mg/kg), Pb (6.67 mg/kg), Ti (736.62 mg/kg), Tl (0.14 mg/kg), and V (33.09 mg/kg) were observed in Enteromorpha intestinalis (green seaweeds). Besides, the highest concentration of Ca (1071.09 mg/kg), Cd (5.81 mg/kg), Mn (1003.41 mg/kg), Sr (2838.86 mg/kg), and Zn (41.95 mg/kg) were found in Padina tetrastromatica (brown seaweeds). Eight metals (Pb, Cd, Zn, Cu, Ni, Mn, Cr, Fe) have been used to assess the potential health risk for adults, but no potential health risk was detected (HQ value 1). The HI value of E. intestinalis and P. tetrastromatica were1, implying that these two seaweeds are not safe for human consumption as there is a carcinogenic health risk for adults.

Salinity is one of the most critical environmental parameters regarding fish physiology, modifying food intake and growth performance in many fish species. The present study has investigated the effects of different salinity levels on growth performance, feeding and survival of Asian seabass Lates calcarifer juveniles. Asian seabass juveniles were reared at 0, 5, 22, 36, and 42 ppt salinity. One five hundred ninety-eight fish individuals with an average weight 1.2 ± 0.11 g were randomly distributed (166 fish/Tank) in 5 concrete tanks (30×6×4 feet) each; length × width × depth) and volume 19,122 L, for total forty days. Initially feeding rate of 6% biomass per day with 42% crude protein-containing diets daily. The feeding rate adjusted according to fish biomass every week. The results showed that salinity level had a significant effect on the weight gain, average daily weight gain, specific growth rate, feed conversion ratio, survival rate, total biomass and health indices (p < 0.05). The highest WG (39.11±1.49 g), ADWG, (1.00±0.12 g), SGR (8.74±0.03 % d-1) and lowest FCR (0.96±0.20) observed with T3 (22 ppt salinity) treatment, which was significantly higher compared to other treatment groups (p < 0.05). Among the health indices, the highest hepatosomatic index and viscerosomatic index found with 22 ppt salinity treatment, which was also significantly higher than the other treatment groups (p < 0.05). No significant differences were found among the treatments in terms of survival rate (p > 0.05), but the maximum survival rate (98.89±0.0 %) in T3 (22 ppt) and T2 (5 ppt). The maximum level of crude proteins (19.99±1.4%) was found in the whole-body biochemical composition (% of wet weight) of Asian sea bass juveniles in T3 treatment group reared at 22 ppt salinity. The second-order polynomial regression showed that 20 ppt salinity is optimum for the best growth of Asian sea bass. Thus, our present work would provide valuable information to the fish farmers for culturing the sea bass as well as its management along the inland and coastline of Pakistan.

The scarcity of arsenic and iron-free safe drinking water is an alarming issue in the southern part of the Bengal Basin. The objectives of the present study were to investigate the spatial distribution of manganese (Mn) concentration in the shallow and deep groundwater and its associated health risks for the children and adults of entire southern Bengal Basin. The Mn concentration in the groundwater varied from 0 to 5.4 mg/L with an average value of 0.47 mg/L that exceeded the WHO's and Bangladesh drinking water guideline values of 0.4 and 0.1 mg/L, respectively. Mn concentration in the shallow wells overrode the deep ones. About 23% of the shallow wells and 11% of deep wells exceeded the WHO's safety limit of Mn concentration for human health. The human health risk related to Mn contamination was estimated by computing the average daily dosage (ADD) and hazard quotient (HQ) values for children and adults. The average computed HQ values found 0.108 and 0.099 for children and adults, respectively. The HQ values delimitated that children are posing a higher risk compared to the adults for the shallow wells. Deep wells were found risk-free for both children and adults. The areal coverage of shallow wells with HQ values1 was minimal compared to the total study area and covered only a small portion of Patuakhali and Barguna districts. The rest of the site does not pose any health risk due to Mn contamination for children and adults.

The bacterial population plays a crucial role in recycling the organic matter and metabolizing the toxic nitrogenous compounds under biofloc technology (BFT). The biofloc technology has been successfully implemented for several fish species, but not for shrimp culture in Bangladesh. The major objectives of this study were to determine the effects of stocking density on the growth performance of tiger shrimp Penaeus monodon under biofloc technology (BFT) rearing system using commercial probiotics and to investigate the abundance of total heterotrophic bacteria (THB) and vibrio-like bacteria (VLB) in different biofloc treatments and their water quality parameters. The experiment was conducted with three different stocking densities in three BFT tanks (2.5 × 2.0 × 1.0 m) with triplicate and three control tanks filled in clearwater. All these tanks were built with cement and can contain 5000 L of water. Visually healthy, disease-free P. monodon postlarvae (weighted 0.18 ± 0.02 g) were collected from a local hatchery and stocked in three different stocking densities, i.e., 400 PL/m3 (CW), 400 PL/m3 (BFT1), 450 PL/m3 (BFT2) and 500 PL/m3 (BFT3). Shrimps were fed four times a day with commercial feed (Biomer, 40 % crude protein) for 127 days. Significant differences (P < 0.05) in specific growth rate, food conversion ratio, and protein efficiency ratio of shrimp were found among the treatments and the control group. The overall final biomass in BFT1 (5.88 ± 0.12 kg m3) was significantly higher (P < 0.05) than that of other BFT groups and the control (3.40 ± 0.09 kg m3). The present findings showed that the biofloc technology with lower stocking density was reducing the total ammonia nitrogen, nitrite-N, and nitrate-N in water and significantly increased THB and reduced VLB populations.

High concentrations of naturally-occurring and man-accentuated boron in groundwater possess a potential threat to the health and well-being of humans worldwide. In Bangladesh, only a few studies focused on the health risks of boron-containing groundwater. Therefore, the present study investigated the spatiotemporal distribution of boron concentrations in groundwater and its associated health risks in the coastal districts of Bangladesh. A total of 268 samples from the shallow and deep wells during the wet and dry season (137 and 131 samples, respectively) were collected to determine the level of boron concentrations and health risk status. The groundwater boron concentrations ranged from 0 to 4.10 mg/L with an average concentration of 0.68 mg/L, which was much lower than the WHO and the values of Bangladesh drinking water standard guideline. The boron concentrations in the shallow wells override the deep ones with insignificant seasonal variation. Boron contamination affected 10% of the shallow wells in the wet season and only 6% of them in the dry season, whereas only 1% of deep wells exceeds the WHO guideline values of 2.40 mg/L during the wet and dry season, respectively. The human health risk of boron was determined by computing estimated daily intake (EDI) and hazard quotient (HQ) values for infants, children, teenagers, and adults. The average HQ value delimitated that children have high risk followed by teenagers, adults, and infants. About 90–95% of the studied samples were free from boron contamination because of having HQ values < 1 and the rest of the samples possess a high risk for children. For the overall study area, the deep wells were found safer than the shallow wells, which were more susceptible to boron contamination aided by localized freshwater inputs.

Proteomics techniques, such as two-dimensional polyacrylamide gel electrophoresis, mass spectrometry, and differential gel electrophoresis, have been extensively used to describe the protein composition of male gametes in different animals, mainly mammals. They have also provided a deeper understanding of protein functions involved in sperm processes, as in processes that in humans lead to male infertility. However, few studies focus on fish sperm proteomics and even fewer have tried to explore the proteomic profile of Sturgeon spermatozoa. Sturgeon is an endangered, ancient group of fish species exploited mostly for caviar. In this fish group, a part of the process that leads to final functional maturation of spermatozoa so as to have the capability to activate eggs during the fertilization process. This process has a broad similarity to post-testicular maturation in mammals; where spermatozoa leaving the testes must be mixed with seminal fluid along the transit through the Wolffian ducts to modify its surface membrane protein composition, leading to axonemal and acrosomal competence. The aim of this study was to review the current literature on various proteomic techniques, their usefulness in separating, identifying and studying the proteome composition of the fish spermatozoon, as well as their potential applications in studying the post-testicular maturation process in Sturgeon. Such understanding could lead to development of more sophisticated aquaculture techniques, favorable for sturgeon reproduction.

The recent incidence of loose-shell syndrome disease (LSSD) in grow-out shrimp ponds appears to be a major problem in Bangladesh. Therefore, the aims of our study were (i) to observe clinical signs of LSSD to confirm its incidence and (ii) to identify the probable causative agents for LSSD in shrimp. Sampling was conducted randomly from five LSSD-affected ponds and three non-affected ponds near Bakkhali River; ecological parameters were measured. A total of 180 healthy shrimps were used for this experiment, where LSSD-affected shrimp extracts were either injected into the shrimps or mixed with water in the experimental tanks. Finally, microbial examinations were performed to identify the possible LSSD causative agents from the infected individuals. The total shrimp production was higher in ponds with healthy populations (185 kg/ha) than from LSSD-affected ponds (126–146 kg/ha); the survival rate of shrimp at harvest was significantly different (p

The age of fish can affect reproductive performance in relation to the gamete quality and productivity which might be expected to be changed in older individuals. The consideration can be important in artificial propagation in relation to the selection of broodstock. We determined the age-related changes in male and female reproductive characteristics of the bighead carp Hypophthalmichthys nobilis and then we examined the effects of age on the male and female reproductive fitness in terms of fertilization, hatching, and larvae survival rate. A total of eight 3–4-year-old males and eight 4–5-year-old females were crossed using a factorial breeding design. Fertilization, hatching, and larvae survival rates were counted. We found no significant difference between 3 and 4 year olds in the sperm motility traits, density, and spermatocrit, but significant differences (p

This study examined the effects of an herbal extract composed of nine herbs i.e Aloe vera, Andrographis pariculata, Annona squamosa, Azadirachta indica, Citrus aurantifolia, Coriandrum sativum, Ocimum sanctum, Ollium cepa and Psidium guajava on growth, survival rate and immunoprotection against pathogenic Vibrio harveyi in the tiger shrimp Penaeus monodon. The petroleum ether, methanol and N-hexen extracts of different herbal plants were selected, processed and thoroughly mixed in equal proportions and added to the shrimp diets at a concentration of 1.0, 2.5 and 5.0 mL kg−1. After 60 days of feeding, shrimps were challenged with V. harveyi bacteria (1 × 107 cells mL−1), which were isolated and propagated from the infected shrimps. The shrimps fed on diets with methanolic extraction of 2.5 mL kg−1 had significantly (P

Contents Seminal plasma (SP) and ovarian fluid (OF) plays an important role as storage media to prevent the activation of gametes both in vivo and under artificial conditions. The objectives of this study were to quantify gamete biochemistry and explore correlations among quantitative characteristics of SP, OF and sperm performance traits of Ide Leuciscus idus and Northern pike Esox lucius. Generally, Na+, K+ and Cl− were found to be the most dominating ions, although concentrations of K+ were higher in SP, while Na+ and Cl− concentrations were higher in OF for both species. Several significant correlations among the biochemical properties such as total protein, glucose, osmolality, cholesterol, K+, Ca2+, Cl− and Mg2+ were observed for SP and OF. Total protein content of Ide SP was positively correlated with sperm activity traits (r ≥ .89, p ≤ .05), while K+ concentration was negatively correlated with sperm traits (r ≥ −.89, p ≤ .05). Moreover, Ca2+ concentration in Northern pike SP was positively correlated with the percentage of sperm motility (r = . 98, p

Size frequency and length–weight relationships (LWRs) for three cephalopods, Indian squid Photololigo duvaucelii, needle cuttlefish Sepia aculeata, and spineless cuttlefish Sepiella inermis were studied. Specimens were caught from the coastal waters of Bangladesh (Moheshkhali Channel and Sonadia Island) using both trawl and marine set bag nets. The maximum dorsal mantle length for the Indian squid, needle cuttlefish, and spineless cuttlefish was recorded to be 228, 135, and 82 mm, respectively. The estimated growth coefficient b was 1.377 for Indian squid, 2.504 for needle cuttlefish, and 1.979 for spineless cuttlefish. The growth coefficient for these three species indicated hypoallometric growth from this region. No information has been published regarding size frequency and LWRs for these three cephalopods from the coastal waters of Bangladesh. The results of this study will be useful for the management and conservation of squid fisheries from the Bay of Bengal.