Identification of two hatch date-dependent cohorts and variation in early growth rate of mud carp (Cirrhinus molitorella) in the Pearl River Delta, China

2018 ◽  
Vol 69 (8) ◽  
pp. 1231
Author(s):  
Yanfei Huang ◽  
Xinhui Li ◽  
Shuli Zhu ◽  
Zhi Wu

Cirrhinus molitorella is one of the most important commercial fish species in the Pearl River, but there are few published studies on the early growth of this species. In the present study, seasonal recruitment patterns, temporal variations in early growth rates and environmental variables were analysed. In all, 1512 individuals were collected during monthly sampling from July 2015 to January 2016, ranging from 30.8- to 84.9-mm standard length (SL). A subsample of 276 juveniles was aged from 68 to 193 days, with hatch dates between 2 February and 19 September, by determining daily increments in otoliths. Monthly abundance data and SL frequency distributions showed that there were two major temporal cohorts of juvenile recruitment, which hatched primarily in April and July. Average growth rate, estimated by the linear relationship between age and SL, was greater for the April cohort (0.49mmday–1) than the July cohort (0.37mmday–1). Mean increment widths from the 23rd increment onwards were significantly greater for the April than July cohort (P<0.05). The slower growth observed in the July cohort was probably due to poorer food availability caused by high river discharge volumes. These results are important for predicting recruitment dynamics and managing the C. molitorella fishery.

2017 ◽  
Vol 440 ◽  
pp. 52-63 ◽  
Author(s):  
Chao Tan ◽  
Bensheng Huang ◽  
Kunsong Liu ◽  
Hui Chen ◽  
Feng Liu ◽  
...  

Author(s):  
Farida . ◽  
Eka Indah Raharjo ◽  
Arnis Maylinda Sari

ABSTRAKPenelitian bertujuan untuk mengetahui penggunaan fermentasi bungkil kelapa sawit dalam pakan buatan.Penelitian menggunakan Rancangan Acak Lengkap (RAL) yang terdiri dari 4 perlakuan 3 ulangan.Susunan perlakuan adalah Perlakuan A : bungkil kelapa sawit 12%, Perlakuan B : fermentasi bungkil kelapa sawit 15%, Perlakuan C : fermentasi bungkil kelapa sawit 18%, Perlakuan D : fermentasi bungkil kelapa sawit 21%. Penelitian ini dilakukan selama 60 hari untuk mengetahui laju pertumbuhan spesifikberat, laju pertumbuhan harianpanjang, konversi pakan, kelangsungan hidup dan kualitas air sebagai penunjang.Hasil penelitian menunjukkan pemberian pakan buatan dengan fermentasi bungkil kelapa sawit menghasilkan respon yang baik terhadap pertumbuhan ikan gurami. Pemberian pakan buatan dengan fermentasi bungkil kelapa sawit 18% (perlakuan C), memberikan hasil terbaik dengan laju pertumbuhan dengan rata – rata laju pertumbuhan spesifik berat 1.502%, laju pertumbuhan harian panjang 4.06%, nilai konversi pakan rata – rata 3.48 dan kelangsungan hidup rata – rata 90%.Kata Kunci : Fermentasi Bungkil Kelapa Sawit, Ikan Gurami, Laju PertumbuhanThe study aims to determine the use of fermentation residue oil palm in artificial feed .Research using a completely randomized design ( CRD ), which consists of 4 treatment three replications.The composition of the treatment is the treatment  A : 12 % of palm oil cake , Treatment B : fermented palm oil cake 15 % , Treatment C : fermented palm oil cake 18 % , Treatment D : fermentation residue palm oil 21 %.This research was conducted for 60 days to determine the specific growth rate of heavy , long daily growth rate , feed conversion , survival and quality of water as a supporter.The results showed the artificial feeding with fermented palm cake to produce a good response to the growth of carp.Feeding artificially by fermentation cake palm oil 18 % ( treatment C ) , gives the best results with a growth rate with the average - average growth rate of the specific weight of 1.502 % daily growth rate long- 4:06 % , the value of feed conversion average - average 3:48 and median survival - average of 90 % .Keywords : Fermentation Palm Kernel Oil, Fish carp, Growth Rate


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