title: Impacts of hatchery-reared mandarin fish Siniperca chuatsi stocking on wild fish community and water quality in a shallow Yangtze lake

authors: Li, Wei

subjects: Science & Technology

abstract: Mandarin fish Siniperca chuatsi, a valuable piscivorous fish, have been stocked into many lakes in China since the 1990s. This study did the first attempt to evaluate the ecological effects of hatchery-reared mandarin fish stocking in the Yangtze River basin lakes. Our study demonstrated a significant change in fish community composition after mandarin fish stocking, but no fish extinction was observed. No significant difference was observed in the total density of 13 forage fish before and after mandarin fish stocking, but the total biomass showed a significant decline after mandarin fish stocking. Significant differences in length-frequency distributions were observed for Carassius auratus, Pseudorasbora parva and Toxabramis swinhonis captured before and after stocking mandarin fish. No significant change in habitat distribution was detected before and after mandarin fish stocking. A marked decline in total nitrogen and a slight decline in total phosphorus were observed while a slight increasing trend for Secchi depth was found after stocking. Our findings suggested that mandarin fish stocking can increase predation pressure on forage fish and subsequently optimize the food web structure. Also, mandarin fish stocking has the potential to improve water quality and may be a feasible strategy to alleviate eutrophication of shallow Yangtze lakes.

text: Impacts of hatchery-reared mandarin fish Siniperca chuatsi stocking on wild fish community and water quality in a shallow Yangtze lake Mandarin fish Siniperca chuatsi, a valuable piscivorous fish, have been stocked into many lakes in China since the 1990s. This study did the first attempt to evaluate the ecological effects of hatchery-reared mandarin fish stocking in the Yangtze River basin lakes. Our study demonstrated a significant change in fish community composition after mandarin fish stocking, but no fish extinction was observed. No significant difference was observed in the total density of 13 forage fish before and after mandarin fish stocking, but the total biomass showed a significant decline after mandarin fish stocking. Significant differences in length-frequency distributions were observed for Carassius auratus, Pseudorasbora parva and Toxabramis swinhonis captured before and after stocking mandarin fish. No significant change in habitat distribution was detected before and after mandarin fish stocking. A marked decline in total nitrogen and a slight decline in total phosphorus were observed while a slight increasing trend for Secchi depth was found after stocking. Our findings suggested that mandarin fish stocking can increase predation pressure on forage fish and subsequently optimize the food web structure. Also, mandarin fish stocking has the potential to improve water quality and may be a feasible strategy to alleviate eutrophication of shallow Yangtze lakes.

year: 2018

title: Book review: Parable and politics in early Islamic history: the Rashidun caliphs

authors: Pratt, Douglas

subjects: book review

abstract: This article reviews the book, “Parable and politics in early Islamic history: the Rashidun caliphs”, by Tayeb El-Hibri.

text: Book review: Parable and politics in early Islamic history: the Rashidun caliphs This article reviews the book, “Parable and politics in early Islamic history: the Rashidun caliphs”, by Tayeb El-Hibri.

year: 2011

title: He pūrongo whakahokinga kōrero a te akomanga rūmaki o Te Tohu Paetahi

authors: Nock, Sophie

subjects: Reo Māori

abstract: Ko te whāinga matua o tēnei rangahau he whakakaokao, he wetewete āno hoki i ngā whakahokinga kōrero a te hunga uiui i kake atu ai ki runga i te waka o Te Tohu Paetahi i te tau 2008, i raro i te kōawa o Rehutai, i raro anō hoki i te maru o Te Whare Wānanga o Waikato. Ka aro atu ki ngā urupare a te hunga tekau mā ono mō te kaupapa nei o Te Tohu Paetahi, ka mutu, ka matapakihia ngā kōrero me ngā whakaaro o taua hunga kia āta kitea ai, āe rānei e tika ana te whakahaere, te mahi whakaako i te reo, te tautoko mai hoki a ngā kaiwhakaako me te kura. I te mutunga iho tautoko katoa te hunga uiui ki aua mea katoa.

text: He pūrongo whakahokinga kōrero a te akomanga rūmaki o Te Tohu Paetahi Ko te whāinga matua o tēnei rangahau he whakakaokao, he wetewete āno hoki i ngā whakahokinga kōrero a te hunga uiui i kake atu ai ki runga i te waka o Te Tohu Paetahi i te tau 2008, i raro i te kōawa o Rehutai, i raro anō hoki i te maru o Te Whare Wānanga o Waikato. Ka aro atu ki ngā urupare a te hunga tekau mā ono mō te kaupapa nei o Te Tohu Paetahi, ka mutu, ka matapakihia ngā kōrero me ngā whakaaro o taua hunga kia āta kitea ai, āe rānei e tika ana te whakahaere, te mahi whakaako i te reo, te tautoko mai hoki a ngā kaiwhakaako me te kura. I te mutunga iho tautoko katoa te hunga uiui ki aua mea katoa.

year: 2012-05