Hydrological conditions of marine fish culture ponds and adjacent inshore waters of Palk Bay near Mandapam during the North-East Monsoon period

In recent years, attempts were being made in India to utilise the coastal lagoons, estuaries and other water bodies for fish culture practices by which the protein uptake of our masses could be increased. Tampi (1960) has proved that the coastal lagoons with low biological productivity can be developed into fish farm

Experimental cultivation of Gracilaria edulis at Valinokkam Bay

Experimental field cultivation of the agar yielding red alga Gracilaria edulis was carried out at Valinokkam Bay from May 1992 to April 1994 at 1.5 to 3.0 m depths using 2x2 m size coir rope nets fabricated with 1" thick coir ropes and 1" thick long line coir ropes. The seedlings cultured on nets and long line ropes during May to December in 1992 and 1993 degenerated due to sedimentation and low light intensity. The growth of G. edulis seedlings from January to April during 1993 and 1994 was good and reached harvestable size of 14.4 cm and 22.9 cm (mean length) after 45 and 90 days respectively. Harvest could not be made, as many of the grown up plants were grazed by fishes. Data collected on environmental and hydrological parameters from the culture site at fortnightly interval were correlated with the growth of cultured seaweed. The result obtained in this experiment is compared with the results on the experimental field cultivation of G.edulis carried out in the near shore areas of Mandapam and lagoon of Minicoy and Lakshadwee

Seaweeds

Research works oti various aspects of seaweeds have been caried out since last five decades. They inchide resources survey, studies on distribution, Uixonomy, ecology, biology, phycocolioids, biochemicals, culture and utilisation of marine algae growing in Tamil Nadu, Kercda, Lakshadwe^p and Andaman-Nicobar Islands. Information was also gathered since 1978 on the quantity of seaweeds commercially exploited from the natural seaweed beds occurring in Tamil Nadu coast. The results obtained on these aspects are reviewed in this paper. The prospects of seaweed research, industry and utilisation in India are also briefly described

Unusual heavy landings of Talang queenfish Scomberoides commersonianus in Chennai coast

Heavy landings of (61.5 t) S. commersonianus (Fig. 1) was landed by hooks & line, mechanised gillnet, trawlnet and other indigenous gears like Pannuvalai (gillnet), Kolavalai (driftnet) and Pachchavalai (castnet) at Kasimedu Fisheries Harbour during January 2005 to December 200

Seaweed resources off Tamil Nadu coast: Sector II. Alanthali - Manapad and Vembar – Nallathanni Thivu

The seaweeds are used for the production of polysaccharides such as agar, algin, carragennan and they are harvested from intertidal regions along the southeast shores of India. The resource potential from intertidal regions was estimated (Anon 1978

Occurrence and growth of the commercially important red algae in fish culture pond at Mandapam

The red algae Gracilaria edulis, Hypnea valenliae, Acanthophora spicifera ard Sarconema irdica have been observed to occur arrl grow in a culture pard. Ove- a period of eight month s, the algae grew to lJ4 kg in the pard of 800 sq m. The hyd rological cordilions in the porn are compared to those in the sea containing natursl beds of these algae during the periro of observations. This occurrence ard growth may open up the ,,4. possibility of growing these algae in culture pards providing the requisite hyd rological ard nutrient corditions

Urban Heat Island mitigation using green roof approach

In urban environments, vegetation has largely been replaced by impervious and often dark surfaces. These conditions contribute to an Urban Heat Island (UHI) effect. This phenomenon is demonstrated in many cities and produced effects such as higher atmospheric temperatures, intensive precipitation, excessive solar radiation and increasing air pollution. Therefore, reducing the surface temperature of roofs in a building may play an important role in improving the conventional roof surfaces with green roofs that offer much lower temperatures throughout a day to reach their thermal performance and reduce the absorption of solar radiation. Thus, this study is focused on determining the effectiveness of the existing green roof in reducing the ambient temperature and humidity of the air above it by comparison with conventional open roof top without vegetation. This study also aims to evaluate the potential of green roof to reduce the air pollutants in improving air quality in urban cities. As a result, by adopting green roof system, it has reduced temperature during the hottest hour in a day at 1230 hour (hr) by 4.3°C when compared to open roof. Green roof has also recorded higher percentage of humidity compared to open roof. Most importantly, it was proven through this study that green roof has the potential of absorbing pollutants in the air by reducing the concentrations of Sulphur dioxide (SO2), Ammonia (NH3), Nitrogen dioxide (NO2), Ozone (O3) and Carbon monoxide (CO) compared to open roof. Thus, green roofs can be considered to be one of the effective methods to mitigate UHI effects in urban cities

Seaweed resources off Tamil Nadu coast: Sector III. Valinokkam - Kilakkarai

Survey of seaweed resources in deep water was carried out in the area between Valinokkam and Kilakkarai during January 1989 and March,l990 respectively. In the survey from Valinokkam to Kilakkarai 33 species of marine algae were recorded of which 8 species belong to Chlorophyta, 8 to Phaeophyta and 17 to Rhodophyta. Only one species of seagrass Halophila ovalis was recorded. Among the 200 sq Icm area surveyed, vegetation occurred only in 27.5 sq.km with a total standing crop of 2962.5 tonnes (wet wt)

Seaweed resources off Tamil nadu coast, Sector - IV Kilakkarai - Rameswaram island (Dhanushkodi

Survey of the deep water area from Kilakkarai (Appa Tivu to Rameswaram Island (Dhanushkodi) was undertaken from December 1990 to January 1991 in the IV Sector survey of Deep water Seaweed Resources off Tamil Nadu coast, which formed the last phase of the survey from Rameswaram to Kanyakumari carried out during 1986-91. An area of 417 .5 sq.km. was surveyed yielding a total biomass of 18,162.5 tons (wet) seaweeds. Out of 167 stations surveyed in 13 transects, vegetation occurred only in 12 stations. Of the 29 species of marine algae recorded 8 belonged to Chlorophyta, 8 to Phaeophyta, 12 to Rhodophyta, and I to Cyanophyta, One species of seagrass Cymodocea serrulata was also recorded. Twenty species were found in estimable quantities, of which the following 8 species were abundant: Halimeda macr%ba, Spatog/ossum asperum, Zonaria crenata, Sargassum ilicijolium, Amphiroa jragilissima, Hypnea muscijormis, Botryocladia /eplOpoda and Lyngbya majuscula with a biomass of 1325, 9775, 650, 1550, 1925,300,862.5 and 1012.5 tons (wet) respectively. The species of Hypnea and Sargassum could be exploited for the manufacture of phytochemicals

Growth of Gracilaria edulis in relation to environmental factors in field cultivation

Field cultivation of Gracilaria edulis was carried out in the nearshore areas of Gulf of Mannar and Palk Bay near Mandapam to determine the various environmental factors which affect the growth of this agar yielding seaweed. These culture experiments were conducted in Gulf of Mannar from October to April during the years 1986-89 and in Palk Bay from April to October during the years 1987-88 when the sea was calm at both places. The epiphytes, epifauna, Low light intensity and sedimentation caused by turbulence of water and grazing by fishes were found to be the primary factors hampering the growth of cultured G. edulis. There was no good growth of G. edulis in Palk Bay during the entire period of this study. But in Gulf of Mannar the growth of G. edulis was good between November and March with maximum yield during the months December to February1 March. The suitable period for field cultivation of G. edulis in Gulf of Mannar is from December to March