Occurrence of isopod parasites in clupeids off Chennai coast, India

The study was carried out to investigate the incidence of isopod parasites in clupeids, with special emphasis on the Indian pellona fish, Pellona ditchela . Two species of isopods, Joryma hilsae and Joryma sawayah were found infecting this fish. The isopods of the genus Joryma are typical Indo-Pacific genus, found infecting the gills of marine fishes. However, this is the first report of these two species in Indian pellona, P. ditchela along the Bay of Bengal off Chennai coast, India. The prevalence (%) of J. hilsae and J. sawayah in P. ditchela recorded during the present investigation were 17.7 and 32.3 respectively. Cymothoids are common isopod parasites of marine fishes and their infection can cause serious damages to the fishes

Blue ring Octopus, Hapalochlaena nierstraszi, from the Bay of Bengal along the Chennai Coast

On 12-08-2012, a rare occurrence of Blue ring octopus {Hapalochlaena nierstraszi (Adam 1938)), with a length of 82-165 mm and weight of 5.5-18 g was recorded for the first time at Kasimedu Fisheries Harbour , Chennai. It was caught by Trawl net gear at a depth of 20-30 m in Bay of Bengal along the Chennai Coast. There are about at least ten species of tiny blue-ringed octopus, which, ironically for their size, are the most deadly of ail cephalopods,but only four have been formally named. All these are inhabitants of Asian-pacific waters. These are; Greater Blue-ringed Octopus {Hapalochlaena lunulata), Lesser Blue-ringed Octopus or Southern Blue-ringed Octopus {Hapalochlaena maculosa), Blue-lined Octopus {Hapalochlaena fasciata) and Hapalochlneno nierstraszi. The common names come from the bright blue rings that appear when they are alarmed or attacked

Occurrence of starry blowfish, Arothron stellatus from Kasimedu Fish Landing Centre, Chennai, Tamil Nadu

The blowfish, locally called as “Pethai” are generally believed to be poisonous. Certain internal organs and sometimes their skin are highly toxic to most animals when eaten, nevertheless the meat of some species is considered a delicacy in Japan (as fugu) and Korea (as bok), when prepared by chefs who know what is safe to eat and in what quantity. Puffer fish is eaten safely worldwide simply by killing and gutting the fish while it is fres

Shrimp farming in Monsoon Season Problems and their mitigation

In this process, several lacunae in the technology of farming that result mostly in disease incidence have been causing concern. It is now felt that there is a perceived need to develop an improved appropriate technology for shrimp farming to poise India to emerge as a long-term sustainable source of shrimp in contrast to the present boom-bust cycle commonly associated with this sector

Innovative aquaculture

With the accelerated human population explosion, demand for fish is also increasing rapidly In Indian context, total fish production comes from the two sectors, marine and inland. It is well evident from the production trend that the fish landings from marine sector have become either almost static or declining. So, aquaculture can be a possible avenue to increase production for meeting the fish demand. Presently, aquaculture contributes around 85-90% of total inland fish production. Aquaculture is defined as the system of breeding and farming of aquatic species in a controlled environment. While innovative aquaculture involves the applications of new and more effective ways or solutions for aquaculture management, there may be interventions related to breeding and farming techniques, aquatic environment management, disease control or animal health monitoring, nutrition and feed management of the cultured organisms, genetics and biotechnological tools which directly or indirectly play roles in improvement of aquaculture production in an environment-friendly and sustainable manner. Here are some innovations which have played or are playing or will play a significant role in the development of aquaculture sector

Record of the sea slug, Kalinga ornata Alder & Hancock, 1864 from the inshore waters of Bay of Bengal along Chennai coast

Sea slugs were caught in the trawl net operated off north Chennai at a depth of around 100-150 m during early hours of 24 June 2011. The specimens were classified and identified as Kalinga ornata and deposited in the Marine Biodiversity Museum of the Central Marine Fisheries Research Institute, Kochi (Accession code: DB. 40.1.1.). Although sea slugs have been found in these waters, there are limited studies on identification to the species level. Kalinga ornata was reported in India during 1936 from Kolkata and further there are no published reports on occurrence of of this species along the east coast of India

Occurence of hammer oyster, Malleus albus near Nachikuppam, Chennai

The hammer oyster, Malleus albus is placed under Class Bivalvia, Subclass Pteriomorphia, Order Pterioida, Superfamily Pteriacea, Family Malleidae. The oyster is locally called suti ali. These oysters (Fig. 1 a and b) were caught by fishermen from Nachikuppam, 1-2 km off Chennai using Nakkuvalai, a bottom set gillnet, at a depth of 5-7 fathoms. The maximum and minimum shell length was 156 mm and 77 mm and the average length and weight were 117 mm and 29 g respectively

Status of Bioprospecting of Marine Molluscs in India

Continuous pressure on the environment arising inevitably or otherwise out of technological progress and human population growth has made it necessary to place a commodity value on biodiversity (Randall, 1991)

First record of the chimaeroid, Rhinochimaera atlantica at Kasimedu Fisheries Harbour, Chennai

Bumper landings of skipjack tuna, Katsuwonus pelamis was observed at Visakhapatnam Fishing Harbour on 28th October 2011, wherein about 42 t were landed by hooks and line

Can We Detect the Anisotropic Shapes of Quasar HII Regions During Reionization Through The Small-Scale Redshifted 21cm Power Spectrum?

Light travel time delays distort the apparent shapes of HII regions surrounding bright quasars during early stages of cosmic reionization. Individual HII regions may remain undetectable in forthcoming redshifted 21 cm experiments. However, the systematic deformation along the line of sight may be detectable statistically, either by stacking tomographic 21cm images of quasars identified, for example, by JWST, or as small-scale anisotropy in the three-dimensional 21cm power spectrum. Here we consider the detectability of this effect. The anisotropy is largest when HII regions are large and expand rapidly, and we find that if bright quasars contributed to the early stages of reionization, then they can produce significant anisotropy, on scales comparable to the typical sizes of HII regions of the bright quasars (approx. 30 Mpc and below). The effect therefore cannot be ignored when analyzing future 21cm power spectra on small scales. If 10 percent of the volume of the IGM at redshift z=10 is ionized by quasars with typical ionizing luminosity of S= 5 x 10^{56} photons/second, the distortions can enhance by more than 10 percent the 21cm power spectrum in the radial (redshift) direction, relative to the transverse directions. The level of this anisotropy exceeds that due to redshift-space distortion, and has the opposite sign. We show that on-going experiments such as MWA should be able to detect this effect. A detection would reveal the presence of bright quasars, and shed light on the ionizing yield and age of the ionizing sources, and the distribution and small-scale clumping of neutral intergalactic gas in their vicinity.Comment: Version accepted by ApJ, with new fiducial model and improved discussio