Aquaculture of the mangrove red snapper

Mangrove red snapper (Lutjanus argentimaculatus) is an important marketable species throughout the Indo-Pacific region. It is a euryhaline species; it can tolerate freshwater, brackishwater and marine water. Modular culture is the common system in snapper production in the Philippines. Stocking density is 4,000 fry per cropping; there could be 2 croppings per year. Brief details are given of investment costs and returns for culture in brackishwater pens.

A new species of catfish of the genus Clupisoma (Siluriformes : Schilbidae) from the Salween River, Yunnan, China

A new species of the schilbid catfish genus Clupisoma Swainson, 1838, was discovered in the Salween River [= Nujiang] of western Yunnan Province, China. There are no previous records of schilbid catfish from the middle reaches of the Salween River before this discovery. Clupisoma nujiangense, new species, is the ninth species of the genus Clupisoma and only the third schilbid catfish species recorded from China.

A morphologically variant natural population of cyprinids without dorsal fin possibly derived from Mystacoleucus marginatus (Osteichthyes: Teleostes) from the Lancang Jiang River, Yunnan, China

In July 2001, 15 grotesque cyprinid specimens were collected in the Lancangjiang River (of the upper reaches of the Mekong River) in Menglun Town, Xishuanbanna Prefecture, Yunnan Province, PR China. These specimens are characterized by surprising characte

A discussion of possible management methods to revive the Labeo victorianus fishery of Lake Victoria, with special reference to the Nzoia river, Kenya

Labeo victorianus Boulenger, the "ningu", is commercially the most important migratory fish of Lake Victoria, as well as being one of the most abundant of all species landed. Annual catch records of the Fisheries Departments of Uganda, Kenya and Tanzania show that a high yielding seasonal, floating gill net fishery is based on the concentration of sexually mature fish at the river mouths at the time of migration during the bi-annual floods. Migrating fish used also to be caught in high numbers at "kek" barrier traps across the river, as at Hainga on the Nzoia river. Since the heavy exploitation at the river mouth which occurred with the introduction of nylon gill nets in 1956.

Fishery methods and fish diversity in the Kilombero River in south-eastern Tanzania

Assessment of common fishery methods and of fish diversity was undertaken in two fishing camps on the Kilombero River in south-eastern Tanzania in surveys towards the end of the dry season, 1994. Fishermen identified 23 different types of fish that they caught on a regular basis. Only 19 species of fish, belonging to 17 genera and 11 families were, however, identified according to Linnean taxonomy. Hooks, nets, traps and spears were used to catch fish. Fish were either sold fresh. or preserved for storage and long-distance tranport by smoking or frying. based un frequency distributions of the numbers of fish landed over a 4 day period at one of the camps, a Shannon-diversity index of 1.95 was calculted. The fork (or total) length of 480 fish and the weight of 413 fish were measured and length frequency distributions as well as length-weight relationships determined for the six most common species. It is concluded that local fishing methods applied in the Kilombero River allow for sustainable fish production.

The role of macrophytes in the economy of the lower Sondu-Miriu river of Lake Victoria

This paper highlights the results of a 12 month's ecological study of macrophytes and their role in the economy of the lower Sondu-Miriu river of Lake Victoria. A total of 34 species of aquatic macrophytes were identified. These were grouped as emergent, floating leaved, free floating and submersed. The major community type identified were dominated by Cladium jamaicanse (Crantz) Kurk., Cyperus paprus (L.) and Cyperus latifolius (Poir). The study observed an over dependence on macrophytes by the local community for the supply of bedding, grazing fields, fuel, roofing and other building materials. The white (heart) of Typha shoot, Nile cabbage (Pistia stratiotes and a legume solanum nigrum traditionally known as "osuga" are used as vegetables by local community. The only source of protein in this arid region is the fish caught in the swamps and birds which inhabit the swamp. The swamp provides the only source of green pasture in the dry season for the animals. An export oriented economy has developed involving mat making and basket weaving with exports reaching as far as Japan. The study proposes a rational and sustainable exploitation of the littoral zone to support the adjacent rural community.

Red-Green-Blue 2D tuneable liquid crystal laser devices

In this paper, we review our recent experimental work on coherent and blue phase liquid crystal lasers.We will present results on thin-film photonic band edge lasing devices using dye-doped low molar mass liquid crystals in self-organised chiral nematic and blue phases. We show that high Q-factor lasers can be achieved in these materials and demonstrate that a single mode output with a very narrow line width can be readily achievable in well-aligned mono-domain samples. Further, we have found that the performance of the laser, i.e. the slope efficiency and the excitation threshold, are dependent upon the physical parameters of the low molar mass chiral nematic liquid crystals. Specifically, slope efficiencies greater than 60% could be achieved depending upon the materials used and the device geometry employed. We will discuss the important parameters of the liquid crystal host/dye guest materials and device configuration that are needed to achieve such high slope efficiencies. Further we demonstrate how the wavelength of the laser can be tuned using an in-plane electric field in a direction perpendicular to the helix axis via a flexoelectric mechanism as well as thermally using thermochromic effects. We will then briefly outline data on room temperature blue phase lasers and further show how liquid crystal/lenslet arrays have been used to demonstrate 2D laser emission of any desired wavelength. Finally, we present preliminary data on LED/incoherent pumping of RG liquid crystal lasers leading to a continuous wave output. © 2009 SPIE.