Herons and fish farming in the Huleh Valley, Israel: Conflict or mutual benefit?

Shoshana Ashkenazi*, Yoram Yom-Tov

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


The impact of populations of the Black-crowned Night-Heron, (Nycticorax nycticorax) and Little Egret (Egretta garzetta), on freshwater commercial fish farms (carp, Cyprinus carpio and tilapia, Sarotherodon spp.) was assessed in the Huleh Valley, Israel. Energy requirement calculations were based on heron population counts, feeding, breeding and survival parameters, daily energy requirement and fish farming management data. The heron populations in the study require 17.2×106 fry, while ponds were populated during the year with 9.8 × 106 fish fry. Moreover, fish of the size found in herons' stomachs throughout the year are available among commercial fish only for a period of 6-8 weeks, twice yearly. It is assumed that the main source of tilapia fry in both herons' diet is from uncontrolled proliferation in the ponds. The presence of the herons contributes to the improvement of commercial fish growing conditions by: (a) reducing density of uncontrolled fish fry; (b) eliminating unhealthy fish; (c) eliminating stocked fish fry predators; and (d) indicating undesired conditions in ponds.

Original languageEnglish
Pages (from-to)143-151
Number of pages9
Issue numberSUPPL.1
StatePublished - 1996


  • Black-crowned Night-Heron
  • Carp Cyprinus carpio
  • Egretta garzetta
  • Energy requirement
  • Fish loss
  • Fishery management
  • Little Egret Nycticorax nycticorax
  • Sarotherodon spp.
  • Tilapia
  • Uncontrolled proliferation


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