Behavioural responses of the mangrove fiddler crabs (Uca annulipes and U. inversa) to urban sewage loadings: results of a mesocosm approach

Mar Pollut Bull. 2009 Dec;58(12):1860-7. doi: 10.1016/j.marpolbul.2009.07.019. Epub 2009 Aug 14.

Abstract

The study aimed at investigating the effects of sewage loadings on the behaviour of two fiddler crabs species maintained in a system of experimental mesocosms, built in a mangrove area in Tanzania and inundated with different seawater/sewage mixtures. Our results show that sewage loads led to a modification of the overall activity budget of the crab community as a result of increased hypertrophic conditions (high COD, increased chlorophyll-a concentrations). During their activity period, crabs inside contaminated mesocosms seemed to satisfy their feeding demand faster than those of the control cells, spending a significant longer time in other activities like courtship and territorial defence. Apart from being a good biological indication of ecosystem eutrophication, such a reduced foraging activity by fiddler crabs also depresses their sediment bioturbation activity, important factor for the health of mangrove systems, suggesting practical implications regarding the efficiency of mangrove-based wetlands for treatment of domestic sewage.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Avicennia / metabolism
  • Behavior, Animal / drug effects*
  • Brachyura / drug effects*
  • Chlorophyllides / analysis
  • Cities
  • Ecosystem
  • Environmental Monitoring
  • Rhizophoraceae / metabolism
  • Seawater / chemistry*
  • Sewage / analysis*
  • Water Pollutants / analysis
  • Water Pollutants / toxicity*

Substances

  • Chlorophyllides
  • Sewage
  • Water Pollutants
  • chlorophyllide a