Perspectives in Marine Aquatic Resources and Health Management

Aquatic resources are now regarded as major contributors to provisioning services that include health-food supply and pharmaceutical products. There are tremendous opportunities to advantageously make use of the rich biodiversity; and the provisioning, regulatory, cultural and supporting services of our seas to meet the emerging demands of humankind. Since biodiversity and ecosystem functioning is inextricably linked to human societies, we have to value the services of both, considering the growing costs of biodiversity loss and ecosystem degradation. A greener environment with enhanced ecosystem services will be beneficial to the ecological and human well-being

Scalar Field Dark Energy Perturbations and their Scale Dependence

We estimate the amplitude of perturbation in dark energy at different length scales for a quintessence model with an exponential potential. It is shown that on length scales much smaller than hubble radius, perturbation in dark energy is negligible in comparison to that in in dark matter. However, on scales comparable to the hubble radius ($\lambda_{p}>1000\mathrm{Mpc}$) the perturbation in dark energy in general cannot be neglected. As compared to the $\Lambda$CDM model, large scale matter power spectrum is suppressed in a generic quintessence dark energy model. We show that on scales $\lambda_{p} < 1000\mathrm{Mpc}$, this suppression is primarily due to different background evolution compared to $\Lambda$CDM model. However, on much larger scales perturbation in dark energy can effect matter power spectrum significantly. Hence this analysis can act as a discriminator between $\Lambda$CDM model and other generic dark energy models with $w_{de} \neq -1$.Comment: 12 pages, 13 figures, added new section, accepted for publication in Phys. Rev.

Ultrastructural changes in the oocytes and hepatocytes associated with the maturation of gonads in the protogynous spinycheek grouper Epinephelus diacanthus (Valenciennes)

Ultrastructural changes in the oocytes and hepatocytes in the female Epinephelus diacanthus were studied with the progress of maturation. Transmission electron microscopic (TEM) observations revealed cytological changes associated with ovarian development. Nucleolus number increased in the perinucleolus stage, which is an indirect indication of increase in protein synthesis with the onset of oogenesis. Zonation of yolk sphere and presence of microvilli in the zona radiata were observed in mature oocytes. In comparison to the immature phase, mature/ripe satge hepatocytes showed greater development of both endoplasmic reticulum and increased density of mitochondria in the cytoplasm which is an evidence of progress in vitellogenin synthesis

Variation in fish catches from the continental shelf between Quilon and Gulf of Mannar and its relation to oceanographic conditions during the southwest monsoon period

The present paper is based on the fishing results of FORV Sagar Sampada during July-August, 1987 along the southwest coast of India. The fish fauna of the Quilon Bank and Wadge Bank has a dominant nemipterid element and the Gulf of Mannar area has a dominant population of barracudas. Nemipterids constituted 88.2 and 64.4% of the total trawl catch from the Quilon Bank and Wadge Bank respectively

Ultrastructural changes in the spermatozoa of the goldspot mullet Liza parsia (Hamilton-Buchanan) in different diluents during cryopreservation

The milt of goldspot mullet, Liza parsia (Hamilton-Buchanan) was diluted with four extenders containing 10% DMSO. Samples were collected at four critical steps of cryopreservation procedure. Percentage of intact spermatozoa and cryoinjuries at each step was recorded. Extender V2E in seawater base +lo% DMSO appeared to be the best cryodiluent as the sperms exhibited least structural changes during the cryopreservation protocol. Chao's extender+lO% DMSO was the next preferred cryodiluent. The suitability of various extenders that accorded protection to injuries was evaluated on the basis of electron microscopic images

Cryopreservation of spermatozoa in the mullet, Liza parsia: Effect of cryoprotectants on morphology and motility

A study was conducted to identify the best cryoprotectant for the spermatozoa of the mullet, Liza parsia (Hamilton-Buchanan), during cryopreservation, based on changes in ultrastructure and motility. Various cryoprotectants alone and in combinations, at different concentrations have been tried. Morphology of spermatozoa before and after cryopreservation was studied by transmission electron microscopy (TEM). A combination of 5% DMSO and 5% glycerol in V2E extender accorded better protection than 10% DMSO alone

Argulus quadristriatus infestation in cage cultured Asian seabass

In Indian waters, genus Netuma is represented by two species namely N. bilineata and N. thalassina (Order: Siluriformes, Family: Ariidae). Rounded shout, thin lips, inconspicuous median longitudinal groove, and higher anal fin ray count (16-19) are characters of N. bilineata while N. thalassina has conical snout, clearly visible median longitudinal groove and lower anal fin ray count (13-15). Prior to the erection of N. bilineata (earlier considered as synonym of N. thalassina) as valid species, Indian workers had difference of opinion regarding the representation of species under this genus from Indian waters

Brief note on infestation of Diplectanum sp. in Asian seabass

Recently open sea cage farming has emerged as an alternative and additional income source for fishermen and fish farmers in India. Asian seabass, Lates calcarifer is widely used in open sea cage culture due to its high market demand. In cage farming, high stocking densities and poor water quality enhance the parasite loads of the cultured fishes. In this study, 47 specimens of Asian seabass collected from cages located in Naganathwada, Sunkeri, Ankola were analysed with the aim of identifying the parasites prevalent among this species. All external and internal organs of each fish were examined separately under microscope for parasites. The collected monogenean parasites were washed in a 0.85% saline solution and fixed in 70% ethanol and identified. Most of the infected fishes had dark coloration of the body and postmortem findings revealed gills with excessive mucus secretion and sticking of the gill tips with greyish coloration

An account of hexactinellid sponge, Hyalonema (Cyliconema) apertum apertum collected from Andaman waters

The hexactinellid sponge collected aboard FORV Sagar Sampada from the eastern side of North Andaman waters at 13o06’ N lat. and 93o11’E long. was identified as Hyalonema (Cyliconema) apertum apertum. This species, collected at a depth of 402 m, belonged to the Class Hexactinellida, Order Amphidiscosida and Family Hyalonematidae. The body is spindle-like, followed by basalia in the form of long twisted spicules. Identical specimens collected from 12o57’ N lat. & 93o07’ E long. and 12o45’ N lat. & 93o09’ E long. confirmed the presence of H. (Cyliconema) apertum apertum in the Central Andaman waters too. The present communication describes the characteristic features of H. (Cyliconema) apertum apertum along with a detailed account of the types and dimensions of spicules

Marine Ecosystem Challenges & Opportunities (MECOS 3)

The Marine Biological Association of India (MBAI), established in 1958, is proud to gear up for MECOS3, the third symposium on Marine Ecosystems- Challenges and Opportunities during 7-10 January, 2020. The MBAI besides organising MECOS1 (2009) and MECOS2 (2014) has inculcated active interest and participation among its members by handling several national and international symposia/seminars, since its formation. The MBAI has 794 life members and 20 institutional members. The mandate of the MBAI is promotion of scientific research in the field of marine biology and allied sciences