Toshi's work

Sinking death syndrome during finfish larviculture Masatoshi FUTAGAWA / CORDUNAP June 30, 2012 Phenomenon Sinking death syndrome occur during early life stage of finfish larviculture, 3 to 7 days post hatch-out (DPH), that larvae settle on bottom at nighttime mostly and it makes mass mortality due to bacteria contamination and anoxia. Several species has the syndrome and that is one of the bottlenecks of mass production. I had the syndrome during the larviculture of Graus nigra , Pacific beakfish ( Oplegnathus insignis ), Japanese flounder ( Paralichthys olivaceus ) and Grater amberjack ( Seriola dumerili ). Causes Increasing body density Finfish larvae consume yolk and oil droplet few days after hatch-out and change body density. Usually, body density of larvae is heavier than water (1.0236±0.0001 at WT 25 ̊C). According to Teruya et al. 2008 , Greater amberjack larva shows it consume yolk and oil droplet until 4 DPH and body water contents reduce from 2 DPH (93.5...

Reduction of coastal fish resources is common problem in the whole world due to overfishing. Qn the other hand, demand is rising due to health consciousness (less cholesterol), contamination of chicken (influenza), cow (BSE) and pork (HEV). Marine ranching is the one of solution to recovering coastal fish resources which has operated in Japan more than four decades. The result shows that some fishes are recovered, even increased, and contribute benefits. Chile coast water has higher productivity compare to Japan and the method produce more fishes quickly. It may create new business model which has less energy consumption, no contamination and sustainable production, and create employment at rural area. 1.             What is Marine ranching 1.1.              Idea and activities General ideas of marine ranching are releasing fish juvenile dismissing species int...

Graus nigra is one of most common species which widely habit at Chile cost. It is called “Vieja”, “Mulato” or “Mulata” locally and which very variable in market. However, the population abruptly decreases due to over fishing recently. Activity of “Marine ranching” is one of solution to recover and enhance natural resources which consists juvenile releasing, artificial reef construction and area management. According to that it is important to develop technique about mass production of juvenile in term of high quality and large quantity in the first instance. Mulata brood stock spawned in cold season, from July to October, naturally and author tried to produce juvenile. Technical development is on the way, it need more study to reach high survival. This study contents mass production method, morphology and habit of Mulata. Refer to "-mulata-technical study-05-pub" that crick "Toshi's" at side bar. Eventually I could not produced any juveniles due to...

The comparison of Mulata spawning in 2005 and 2006 as below. Wild captured G. nigra are rearing at UNAPDCM since 2002 and it starts spawned from 2002. Seven females (biomass 14,056 g) spawned 9,551,611 eggs with 83 times spawning under water temperature 15.8 ± 0.89 ° C from July 13 to November 1, 2005 . Spawned egg consist 6,956,117 floating eggs (72.8%) and it produces 4,487,154 hatch-out larvae (64.5%). Six females (biomass 13,035 g) spawned 15,657,954 eggs with 94 times under 16.5 ± 0.63 ° C from June 11 to October 17, 2006 . Spawned egg consist 7,947,405 floating eggs (50.8%) and it produces 5,422,681 hatch-out larvae (68.2%). G. nigra spawn several times in a spawning season and the spawning quantity per fish body weight shows 679,500 eggs/Kg in 2005 and 1,202,224 eggs/Kg in 2006. The strong relation shows between egg quantity and the average water temperature while 3 days before spawning and it abundant at WT 15.50 ° C in 2005. It has more spawning quantity at 16 ° C...

This is the spawning analysis of Graus nigra on 2005. Remarkable point is the method can identify the period and water temperature of maturation based on simple mathematics method. Abstract is below. Graus nigra is one of most common species which widely habit at Chile cost. Wild G. nigra brood stock, 7 female (BW 950 to 5,350 g) and 11 males (550 to 3,590 g), are reared at facilities of Universidad de Arturo Prat, Ciencias del Mar marine laboratory in Iquique Chile . G. nigra fatness rise to 35 to 42 and spawned naturally from July to October 2005. Spawning occurred 83 times and 9,551,611 eggs are collected in this term. Spawning occurred at water temperature 14 to 17 C. G. nigra produce large quantity and high quality fry at 15.0 to 15.5 C. Refer the file "-mulata-spawning-060516-en" at 　 http://groups.google.com/group/toshif Este analisis del desove de Graus nigra en 2005. Punto importante ha destacar es la utilizacion de un metodo con el cual pod...