Comparison of Tilapia Oreochromis niloticus and native cichlid Herichthys cyanoguttatus in aquaculture conditions

Abstract

Native species, in comparison to exotic species in aquaculture, such as Tilapias, are an alternative with a lower risk to regional biodiversity, due to competition for resources caused by introduced species. Overall productivity, length-weight relationship and relative condition factor of native cichlid Herichthys cyanoguttatus were investigated in comparison to Tilapia Oreochromis niloticus . Fish with a wet weight of 0.54±0.07 g were placed in 100 L tanks inside a polyethylene greenhouse during 84 days. Wet weight (g) was obtained each week and standard length once per month. A significant difference was found in growth (p -1 for Tilapia and 1.35±0.02 % d -1 for the native cichlid, Tilapia reached twice the total weight gain than the native cichlid (31.26±0.95 g; 83.70±4.54 g). Food conversion rate was higher in H. cyanoguttatus than in Tilapia. Both species had a high survival rate with a relative condition factor close to 1, showing a length-weight relationship with an isometric growth, meaning that they were in good condition. The high efficiency of food conversion for H. cyanoguttatus, as well as the relationship of isometric growth and condition factor of both species, suggests that H. cyanoguttatus has the ability to grow in aquaculture systems. The results show that the native species could not compete directly with exotic species due to their differences in biomass production during the experimental time. Normal 0 false false false ES-MX JA X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:Table Normal; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin-top:0cm; mso-para-margin-right:0cm; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0cm; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; mso-bidi-font-size:10.0pt; font-family:Calibri,sans-serif; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-ansi-language:ES-MX; mso-fareast-language:JA;}