Action: Exclude fish with barriers
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- One controlled study in Mexico found that excluding fish using a barrier increased weight gain of axolotls.
Fish can have negative impacts on amphibian populations, either through predation of eggs and larvae or through competition for food. In some cases barriers can be constructed within water bodies to create refuge areas for amphibians.
Supporting evidence from individual studies
A controlled study in 2009 of a canal within agricultural land in Xochimilco, Mexico (Valiente et al. 2010) found that filters to exclude competitive fish and improve water quality resulted in increased weight gain in axolotls Ambystoma mexicanum. Only four of 12 previously marked axolotls were recaptured; however, their weight had increased by 16%. Weight gain was greater than that of axolotls in control colonies over the same period. Farmers traditionally created canals linking lakes and wetlands. Working with farmers in 2009, one canal used as a refuge by axolotls was isolated from the main system using filters made of wood to exclude fish and improve water quality.