Triploidy induction by heat-shock treatment in red tilapia

The possible use of sterile triploid red tilapia is an interesting option for culture due to their proliferating breeding activities. The aim of the present study was to investigate and optimize the time of heat-shock treatment to prevent second polar body extrusion from the newly fertilized eggs of red tilapia, to produce a maximum number of triploid individuals. Heat-shock treatment was applied at a temperature of 41 degrees C for a total duration of 3.5 minutes after 2, 3, 4, 4.5, 5 and 6 minutes of fertilization. The best survival rate (67.0) and triploid percentage (89.7) was observed for the treatment at 4 minutes after fertilization. It is thus successfully demonstrated that 4 minutes after fertilization was the most suitable timing of heat-shock treatment for second polar body retention in newly fertilized eggs of red tilapia

Distribution, threats and conservation status of <i>Hypselobarbus thomassi</i> (Day, 1874), a poorly known cyprinid fish of the Western Ghats freshwater ecoregion

The Red Canarese Barb, Hypselobarbus thomassi (Day, 1874) is an endemic cyprinid fish of the rivers of the Western Ghats of India, which has been listed as ‘Critically Endangered’ in the IUCN Red List of Threatened Species. Like many of its congeners, H. thomassi is poorly known with very few verified records and voucher specimens in the past decades. Based on fresh materials collected from three west flowing rivers of Kerala, we provide information on its identity, distribution, phylogenetic position, threats and conservation. An updated conservation assessment of this species following the IUCN Red List criteria is also provided