Does low temperature cause mummichogs (Fundulus heteroclitus) to bury in sediment over winter?
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Date
2019-04
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University of New Brunswick
Abstract
Winter is a major constraint on the persistence of temperate fishes due to low temperatures and low food availability. In response, fishes have evolved overwintering strategies, for example winter dormancy. Although ecologically important, mummichog (Fundulus heteroclitus) overwintering behaviours are poorly understood. Reportedly, mummichogs bury during winter, but previous studies have been largely anecdotal or indirect observations. To investigate if winter temperatures trigger winter dormancy and burying, mummichogs were provided with a mud substrate or PVC pipes to be used for refuge and exposed to winter cold temperatures (2oC). Activity levels and burying behaviour were monitored alongside a control group (14oC). Although mummichogs reduced activity and feeding, they remained vigilant to disturbances. Sheltering (burying and in pipes) increased but was exhibited by a small proportion of individuals at any given time. Consequently, mummichogs are winter quiescent (reduced activity while remaining vigilant), rather than burying and becoming completely inactive (i.e. winter dormant)