The study emphasizes reproductive biomomics, population structure and length-weight relationship of spotted scat, Scatophagus argus , off Indian waters. Sampling from Ennore, Muttukadu, and Mandapam along the South-east coast of India registered their occurrence during the south-west monsoon (June to August) and north-east monsoon (October to December) with peaks during July and November. There exists a biased sex ratio towards females in the spotted scat population. Reproductivity performance was assessed based on the gonad-somatic index, which aptly correlated with peak spawning season. This led to a description of six stages of ovarian and testicular development. Histological studies further revealed five stages of oocyte and four stages of sperm maturation. Morphometric analysis indicated that the total length (TL) of the fish in the samples ranged from 9.2 cm to 18.3 cm in females and 12.0 cm to 17.6 cm in males. Length-weight equations of w = 0.0337 L 2.998 and w = 0.055 L 2.804 were derived for females and males, respectively. The relationship showed that the exponent “b” value was below 3, with a negative allometric equation documenting compressed body shape. This study provides baseline data on the population structure, length-weight relationship, sexual maturity, and spawning periodicity of Scatophagus argus in Indian waters.

We document the morphology, morphometric variations among the morphotypes of the brine shrimp, Artemia franciscana. From the samples collected at four different locations in South India, Tamil Nadu viz. Kelambakkam, Vedaranyam, Tuticorin and Nagarcoil we identified six morphotypes: M1, M3, M4 in males and F1, F2, F3 in females. The Scanning electron micrographs of male morphotypes show distinct variation in the basal width, shape and number of cuticular cones on the second antennae. Similarly, the female morphotypes show various shape and sizes of the ovisac with or without spines. However, the cyst surface topography is smooth without any specific variation/ ornamentation in all three female morphotypes. Multivariate analysis of eighteen morphological traits measured in males and fifteen in females to elucidate the intraspecific variations among morphotypes indicate significant dissimilarity between males and females. Furthermore, relative length measurements showed distinct morphometric variation of traits between the morphotypes encountered at different sampling sites.

This study emphasizes the need for sperm quality assessment and cryopreservation strategy in the spotted scat Scatophagus argus as the occurrence of male population of this species is limited. Analyses of sperm quality were made including ionic content and osmolality of seminal plasma and blood serum. Sodium chloride (0.9%) was optimized as the extender with a dilution ratio of 1:3 (milt:cryomedium) for all experiments. Cryoprotectants including dimethyl sulfoxide (DMSO), dimethyl acetamide (DMA), glycerol (GLY), propylene glycol (PG), ethylene glycol (EG) and methanol (MeOH) were screened at various concentrations and equilibration times. Cryopreservation was performed using the cryoprotectants DMSO, GLY, EG, and MeOH individually as well as in combinations. Experiment 1 was done with DMSO, GLY, EG and MeOH (5, 10 and 15%); experiment 2 was done with DMSO (5%) + GLY (5%), DMSO (5%) + EG (5%), DMSO (5%) + MeOH (5%). Simultaneously, experiment 3 was done with both cryoprotectants and co-cryoprotectants viz. DMSO (5%) + egg yolk (5%), DMSO (5%) + coconut water (5%), DMSO (5%) + tomato water (5%) and DMSO (5%) + honey (5%). The cooling sample was optimized and performed with a one-step freezing protocol of -5 degrees C/min from 25 degrees C to -150 degrees C. The results indicated that samples subjected to experiment 2 using DMSO (5%) + EG (5%) for 60 days of storage registered maximum motility (82.33 +/- 2.51%), duration time of sperm motility (10.45 +/- 1.01 min) and viability (84.14 +/- 5.29%) of post-thaw cryopreserved sperm. Morphology and ultrastructure of post-thaw sperm showed smooth surface topography and normal architecture of cellular organelles. Biochemical analysis indicated a reduction in the protein content of post-thaw cryopreserved sperm. DNA integrity (Comet assay) showed 6.30 +/- 1.00% of tail DNA in post-thaw sperm, whereas fresh sperm registered 2.41 +/- 1.85%. Functional integrity using the HOST of post-thaw sperm showed a maximum of 82.66 +/- 1.15% with DMSO (5%) + EG (5%). Finally, fertility of postthaw sperm using mature eggs of wild-caught females indicated the entry of sperm by breaking the vitelline membrane. Overall it was demonstrated that the DMSO (5%) + EG (5%) was amenable to the long-term preservation of sperm. Therefore, this protocol can be used as an alternative for male broodstock development under captive breeding program.

Artemia franciscana is a universal live feed in aquaculture, and it has been reported as an invasive species in many Asian hypersaline ecosystems. The present observations illustrated the pre- and postembryonic development stages of the A. franciscana population confined to the Indian saltern of Kelambakkam. We observed their growth patterns during various hydration periods with specific time intervals. Results showed differences in the development stages with respect to unique identity. Interestingly, a period of hydration showed notable cellular movement toward clockwise positions in the hydrating cysts. After 10 h of hydration, blastocoel appeared, accelerating the dynamic route of nuclei movement. At the end of the invagination, the embryo burst out of the cyst, and a sequence of emerging stages was noted. With reference to light microscopic observations, a series of developmental stages were observed, and each instar was documented by developing limb buds of nauplii. Excitingly, the 10th and 11th instar stages reveal sexual differentiation between male and female individuals. Thus, the laboratory culture study clearly documented the different developmental stages with their specific characteristic features. However, further molecular study would provide a cellular basis for understanding the early development of A. franciscana.

This study evaluates the quality and optimization of cryopreservation protocol for sperm of Rachycentron canadum, (Cobia) by screening various cryoprotectants, extenders, freezing protocols and equilibration times. Earlier studies on toxicity assay confirmed the suitability of the extender marine fish ringer and cryoprotectants such as DMSO, EG and DMA for long-term storage. Experiments were performed with milt along with extender, cryoprotectants (DMSO, DMA and DMSO + EG) at dilution ratio of 1:40 and equilibration time of 15 s with single step freezing protocol (-6 degrees C/min from 4 C to -150 C and in LN2 at -196 C). The outcome of these experiments revealed that the sperm quality (motility, viability, functional integrity and DNA damage) was high with DMSO (5%) + EG (5%) compared to other individual and combination of cryoprotectants after 120 days storage. Maximum sperm motility of 62.8 +/- 2.7% and viability of 72.4 +/- 1.9% registered with DMSO (5%) + EG (5%). With reference to morphology, the post-thaw cryopreserved sperm of DMSO (5%) + EG (5%) showed intact sperm without any distortion. Under TEM also showed normal architecture of cellular organelles and plasma membrane. Metabolic enzymes activities (LDH, Asp and ALP), were high in post-thaw cryopreserved sperm with DMSO (5%) + EG (5%) compared to other cryoprotectants, but lesser than control. Similarly, antioxidant enzymes (SOD, GPx and LPO) registered high with DMSO (5%) + EG (5%), but low LPO compared to other cryoprotectants. Comet assay of post-thaw cryopreserved sperm of 120 days storage showed minimum DNA damage (5.84 & PLUSMN; 1.8%) with DMSO (5%) + EG (5%). Functional integrity of post-thaw cryopreserved sperm registered maximum of 68.7 +/- 3.6% with DMSO (5%) + EG (5%). This protocol thus established remarkable cryoresistance of cobia sperm; imply to be amenable for long-term storage.

We document morphology and genetic relatedness of morphotypes within the Artemia franciscana that has colonized Covelong saltern in Kelambakkam (South India). They exhibits high phenotypic plasticity and intra-population variation in a supposedly panmictic population. Morphometric analysis was carried out on 18 traits in males and 15 in females and subjected to multivariate analysis. Three types each in males (M1, M3 and M4) and females (F1, F2 and F3) were singled out. The axes in the plot explain 77.9% in males and 73.9% in females of the variation through discriminant function analysis. The sequence divergence of the population was evaluated through mtDNA (16S rRNA) and nDNA (p26 gene) markers. The substantial sequence divergence was observed between the morphotypes through nDNA and appearing sequence divergence was recognized by mtDNA. Likewise, phylogenetic analyses of maximum likelihood and Bayesian analysis through nDNA revealed a maximum similarities between M1, M4 with F1 & F2 and M3 with F3. Further, haplotype distribution of nDNA revealed unique haplotype between M1 and M4 with F1 and F2 morphotypes. This study thus confirms the occurrence of morphotypes with specific characteristics inside a seemingly homogeneous population.

The brine shrimp Artemia franciscana consists of a complex of phenotypes within a population confined to various salterns in southeast coast of India. Studies are scarce for their occurrence based on morphology and morphometric traits, while seldom any on their genetic variability. Therefore, the present study investigates the genetic variability among the populations of Artemia franciscana samples collected from four different hypersaline habitats Kelambakkam (KBM), Vedaranyam (VDM), Tuticorin (TCN) and Nagarcoil (NGC) from southeast coast of India. Since the genetic variability could be anywhere in their genomes the study was analyzed using two different Random Amplified Polymorphic DNA (RAPD) markers such as (i) the Operon series (OPK) and (ii) Enterobacterial Repetitive Intergenic Consensus (ERIC). The OPK primers generated 367 fragments which indicated polymorphism of 85.29%, Nei's diversity index of 0.25 +/- 0.16 and Shannon's index as 0.39 +/- 0.22 among the population. Furthermore, ERIC-PCR generated 138 fragments with 20.83% of polymorphism while the Nei's diversity and Shannon's index was 0.06 +/- 0.13 and 0.10 +/- 0.20 respectively. Interestingly, operon primers of OPK3 and OPK17 revealed the presence of genetic variations among the populations, and the results were consistent with ERIC markers. Scatter plot and cluster analyses revealed the existence of two major groups in the population collected from the study sites; one with KBM and VDM, while other with TUT and NGC. Hence, the present investigation attributes the genetic variations in a panmictic population of A. franciscana which exist as two distinct groups.

The invader brine shrimp Artemia franciscana is a micro-crustacean with diverse morphology and morphometric traits that are found in hypersaline habitats of Asian countries. In this study, we used the mtDNA control region to assess the impact of colonization of A. franciscana on genetic diversity and population structure encountered in different sampling sites of the southeast coast of India. Samples were collected from four hypersaline habitats includes Kelambakkam (KBM); Vedaranyam (VDM); Tuticorin (TUT) and Nagarcoil (NGC). Genetic diversity of the populations were assessed based on the sequence of a conserved region of the mtDNA control region (CR). For this study, a primer based on the conserved region of a closely related crustacean group was used to sequence the 493 bp of the mtDNA CR. Results indicated a clear demarcation with the existence of sequence divergence between the populations studied. Maximum likelihood and Bayesian phylogenetic studies revealed that the population of TUT, VDM and NGC formed a single cluster whereas the KBM formed a separate cluster with distinct genetic characteristics. The mean haplotype diversity and nucleotide diversity of the four populations were found to be 0.742 +/- 0.060 and 0.012 +/- 0.016, respectively. Interestingly, we observed that these different populations had unique haplotypes varying with their habitats, demonstrating sequence divergence in the ho-mogenous population of A. franciscana despite them being in a similar geographic zone.

The present study emphasizes the possible impact of coastal water quality on marine zooplankton community from six different sampling sites of south India (Kalpakkam, Nemmeli, Muttukadu, Kasimedu, Ennore and Kattupalli). Water Samples were collected in the sampling sites and physicochemical parameters were studied. The results showed significant variations in the concentration and distribution pattern of selected physicochemical parameters (temperatures, pH, salinity, DO, NO-3, NO-2, NH3, PO43- and SiO2) and heavy metals (Ni, Cu, Zn, Pb, Fe, Mg, Co, and Cr). The concentration of nutrients and trace elements were reported high at site IV (Kasimedu) and low at site II (Nemmeli). Further, diversity indices showed maximum Shannon_H and Simpson_1-D indexes (H = 3.492; D = 0.966) at site IV (Kasimedu). Similarly, low diversity indices (H = 3.128; D = 0.9508) was registered at site II (Nemmeli) and site III (Muttukadu), indicating plankton population was attracted by high concentration of nutrients loads in the study areas. Finally, genotoxicity (genomic integrity) was assessed by DNA fragmentation and alkaline comet assay, which resulted in maximum genomic integrity loss for the sample collected from Kalpakkam (42.84 +/- 08.38), Ennore (41.44 +/- 06.59), and Kasimedu (39.5 +/- 09.68) sites. The results revealed that the maximum heavy metal concentration has impact on the zooplankton population as evidence from DNA fragmentation compared with that of freshly hatched out Artemia nauplii as control. Hence, the present investigation documents the alarming threat in coastal water quality which will have an impact on the zooplankton community in selected coastal zones. (C) 2020 Published by Elsevier B.V.

The present study documents the possible effects of Tinospora cordifolia leaf extract supplemented diets on growth, survival and haematobiochemical profiles of the catfish, Pangasius sutchi fingerlings.P. sutchi fingerlings were fed with formulated diets, supplemented with four different concentrations of T. cordifolia leaf extract (viz.100, 200, 400 and 800 mg kg -1 of feed) for 45 days.Fingerlings fed with basal diet served as control.Various parameters of serum biochemical and haematology such as serum total protein content, albumin content, globulin content, albumin globulin ratio, glucose, erythrocytes count, leucocytes count were evaluated along with growth parameters.The results indicated that Specific Growth Rate (SGR), Feed Conversion Ratio (FCR), Protein Efficiency Ratio (PER), survival and Haemato-biochemical profiles such as total serum protein, albumin, globulin, albumin globulin ratio and serum glucose were high in the fingerlings fed with T. cordifolia leaf extract supplemented diets, irrespective of dosage, compared to control.Among the four concentrations of T. cordifolia leaf extract used, 200 mg/kg of feed group showed increased growth, survival and enhanced the health status of P. sutchi fingerlings.

The present study investigates the impact of environmental factors on the occurrence of morphotypes in Artemia franciscana (Article 4; ICZN, 2000) encountered from different salterns of Tamilnadu, southeast coast India. Samplings of brine shrimp were done at four different sites (Kelambakkam, Vedaranyam, Tuticorin and Nagarcoil) on a seasonal basis from December, 2014 to August, 2016. Variations of physicochemical factors (temperature, pH, salinity, DO, nitrate, nitrite, ammonia, phosphate and silicate) were recorded in water samples at all the sampling sites. Intensive survey indicated the occurrence of morphotypes M1, M3, M4 in males and F1, F2, F3 in females from all sampling sites. Principal component analysis, Pearson’s correlation and regression analysis indicated that all physicochemical factors are not significantly correlated with the occurrence of morphotypes. From these studies, it is evident that morphotypes are not seemed to be influenced by physicochemical factors prevailing at the salterns. However, the variation in water temperature seems to influence the abundance of morphotypes M1 and M4 in males and F1 and F2 in females from all the sampling sites, which was further confirmed by cluster analysis.

The effects of osmolality and pH of the seawater and non-ionic media (glucose) on sperm activation in Mugil cephalus was evaluated. The effect of cryopreservation was documented by cryopreserving the sperm diluted with a cryomedium (V2 extender + 10% dimethylsulfoxide) in a programmable freezer. The highest motility grade (4) or (3) was recorded when sperm were activated with seawater with osmolality above 600 (mOsmol/kg) and pH 6 to 9. Significant difference (P < 0.05) was found in the duration of sperm motility with pH 7 (316 +/- 8 s) followed by pH 6 and pH 8.2. In non-ionic media, the highest motility grade (4) and maximum duration of sperm motility (152 +/- 23 s) was recorded when sperm activation carried out with 800 mM of glucose. The frozen-thawed sperm registered a motility grade of 2.44 +/- 0.72. Frozen-thawed spermatozoa revealed changes in ultrastructure like damage of plasma membrane around the sperm head, shrinkage and swelling of the mid-piece region, partial fragmentation, and complete loss of flagellum when observed under electron microscope. However, comet assay indicated a non-significant (P > 0.05) DNA damage in frozen-thawed spermatozoa (3.68 +/- 2.69% of tail DNA) compared to fresh spermatozoa (3.01 +/- 2.13% of tail DNA). Over-all, the sperm activation experiments indicated that sperm of M. cephalus can be activated by a media having osmolality above 600 (mOsmol/kg) and pH ranging from 6 to 9. Although DNA damage is minimal in frozen-thawed spermatozoa, the ultrastructural changes are prominent. Therefore, further experiments are required for the modifications of the composition of cryomedium to minimize the cryodamage.

To test the toxic effects of tributyltin (TBT), Macrobrachium rosenbergii were exposed to three concentrations of TBT viz. 10 ng/L, 100 ng/L and 1000 ng/L for 90 days. The bioaccumulation of TBT level varied in hepatopancreas based upon dose dependent manner. Histopathological results revealed the reduction in basement membrane thickness, disruption of the hepatopancreatic tubules and abnormal lumen in hepatopancreas of TBT treated prawns. The ultrastructure of the control prawn showed normal architecture of cellular organelles with prominent nuclei in hepatocytes. On the other hand, many vacuoles, irregular arrangements of microvilli, swollen mitochondria, distorted rough endoplasmic reticulum cisternaes and abnormal nucleus were seen in the TBT treated group. Further, the biochemical and vitellogenin content were altered remarkably due to TBT exposure. It directly indicated that TBT had conspicuously inhibited the vitellogenesis. Therefore, it was inferred that the administration of TBT has considerably affected the hepatopancreatic functions in M. rosenbergii.

Ultrastructure and development of spermatozoa in cobia, Rachycentron canadum are described. Sections through the testis show different developmental stages viz, Spermatocytes, spermatids and sperm. Spermatozoa of R. canadum exhibit the configuration of uniflagellated, anacrosomal Type I aquasperm, typical for externally fertilizing fish. Mature spermatozoon is seen with a prominent head and long cylindrical flagellum. Ultrastructure of sperm shows invaginated 'U' shaped nucleus and other organelles. The mitochondrial matrix is electron-dense with irregular arrangement of the cristae. The nucleus reveals a deep invagination (nuclear fossa) in which the centriolar complex is located. The centriolar complex lies inside the nuclear fossa and is composed of a proximal and a distal centriole. The two centrioles are placed perpendicular to each other. The flagellum has a typical eukaryotic organization (microtubule doublets 9 + 2 pattern) and measures around 36.21 +/- 0.42 mu m in length. This study for the first time provides a comprehensive detail on the ultrastructure and developmental process of sperm in cobia, R. canadum.

The present study documents the occurrence of an intersex condition in a natural population of mullet Mugil cephalus L. On closure examination of the dissected fish, 11 females and 7 males were recorded. Histological observations through the testes indicated that one of the male fish showed different developmental stages of oocytes in between the seminiferous tubules. Interestingly, the condition reported here did not show any internal bilateral division of the reproductive system into male and female components. But it had shown the occurrence of oocytes and spermatozoa throughout the entire region of the testis of a functional male. The observation of intersex testis or testicular oocytes (TO) is of first report from the east coast of India. The fish being catadromous, this condition may be related to possible accumulation of chemical contaminants in the habitat water.

This study documents the cascade of events that occurred in the coast and biota of the Chennai region exposed to an accidental oil spill near the Ennore port after the collision of two cargo ships. The impact of the collision was so severe that the oil compartment was damaged, spilling approximately 22 tonnes of oil at initial hours. Due to waves, tidal action and southern current, the spillage travelled a long distance up to a stretch of around 52 km along the coastline in Bay of Bengal. Damage to the biota was monitored at different zones based on the intensity of the oil spill to evaluate the environmental impact caused by it. The shorelines of most of these areas had shown signs of oil sludge deposited in the sediments and boulders from the very next day of the collision. An intensive survey indicated that the sea turtles, crabs, fishes and seaweeds were washed ashore that posed a threat to the coastal habitat. Further, in-depth, histological studies on gills, hepatopancreas and eggs of the crab Grapsus albolineatus, showed structural deformities with irregular gill tips and lower haemocytes counts in the gill samples. Whereas hepatopancreas and eggs did not show any structural deformities, although they appeared black due to adhesion of oil, but no sign of oil in the internal region. This pilot study provides baseline information about the post oil spill scenario of the coastal region as alarming and a threat to ecologically sensitive marine organisms. Available online at: www.mbai.org.in doi: 10.6024/jmbai.2017.59.2.1989-08

This study focused on the quality of sperm obtained from spermatophores of cadaveric shrimp after long-term storage. Spermatophores were collected using the stripping method, which has resulted in maximum sperm viability when this approach was previously used. Cryoprotectants toxicity assessment of samples was conducted using dimethyl sulfoxide (DMSO), methanol (MeOH), ethylene glycol (EG), glycerol (Gly), dimethyl acetamide (DMA) and propylene glycol (PG) at different concentrations (5%, 10% and 30% v/v), prepared in Ca-F saline. Based on the results from the cryoprotectant toxicity assay, DMSO and MeOH were used individually as well as in combination for the subsequent study. Samples along with cryoprotectants were subjected to slow and fast freezing protocols (i.e. -0.5, and -10 degrees C/min to a final temperature of -80 degrees C) and were subsequently stored in LN2 (196 degrees C). Similarly, vitrification was performed by plunging the samples directly in to LN2. Samples of control and cryopreserved spermatophores that were stored for 45 days had sperm viabilities of 91.4 +/- 3.6% and 53.9 +/- 4.7%, respectively. Further observations with HOST and DNA integrity analyses of the cryopreserved sperm, resulted in percentages of 45.6 +/- 4.2%; 58.1 +/- 1.7% compared to control values of 82.3 +/- 4.8%; 94.3 +/- 1.9%, respectively. Use of the one-step slow freezing protocol at the rate of -0.5 degrees C/min between 4 degrees C and -80 degrees C in LN2 with DMSO (5%) + MeOH (5%) was a desirable preservation strategy of spermatophores, compared to other freezing protocols. Unlike sperm viability, the HOST results affirm the fertility potential of the sperm that have the capacity to participate in the fertilization process. Thus, the results of this study demonstrate that long term storage of sperm in spermatophores of Fenneropenaeus indicus collected from cadaveric specimens can result in viable sperm after cryopreservation if extender (Ca-F saline) containing DMSO and MeOH are used.

Resisting degradation, nonylphenol (NP) remains as a critical compound contaminating many habitats. Prevalence of nonylphenol in the ecosystem of Indian coastlines is not well documented as that of fresh water. Hence, the present study was intended to estimate the concentration of nonylphenol from water and sediments samples of Chennai (Madras) coastline which is polluted with anthropogenic activities from the city.

The quality of the invader brine shrimp, Artemia franciscana, colonized in Covelong salt works, Kelambakkam (South India) was evaluated based on biometrics, hatching characteristics and nutritional composition of cyst and freshly hatched nauplii. Hydrated cysts measured 238.31±10.42 μm in diameter, while the freshly hatched nauplii measured about 429.00±12.19 μm in length. A hatching of 76.80±5.68% was obtained with hydrated cysts. Time required to obtain 90% hatching was 22.31 hrs for this strain. The hatching synchronization time was of 4.41 hrs. The proximate composition of the decapsulated cysts and newly hatched nauplii showed high level of protein, energy content and low ash content. Fatty acids analysis of the freshly hatched nauplii indicated low level of EPA and absence (or undetectable) of DHA.