DAO 78:169-172 (2007)  -  DOI: https://doi.org/10.3354/dao01863

Diel variation in egg-laying by the freshwater fish louse Argulus foliaceus (Crustacea: Branchiura)

A. J. Harrison1,*, N. F. S. Gault2, J. T. A. Dick3

1Queen’s University Belfast, Fisheries and Aquatic Ecosystems Branch, Department of Agricultural and Environmental Science, Newforge Lane, Belfast, BT9 5PX, UK
2Agri-Food and Biosciences Institute, Food Science Division, Newforge Lane, Belfast, BT9 5PX, UK
3Queen’s University Belfast, School of Biological Sciences, 97 Lisburn Road, Belfast, BT9 7BL, UK

ABSTRACT: Removal of deposited eggs could be a useful control strategy for the damaging fish ectoparasite Argulus foliaceus, but focused control requires knowledge of egg-laying patterns. Here, we investigated diel changes in the egg-laying behaviour of a natural population of A. foliaceus. Data were collected from 17-28 May 2004. Days were divided into 3 time periods: 06:00-14:00, 14:00-22:00 and 22:00-06:00 h. Significantly more egg clutches were laid from 06:00-14:00 h than during the other 2 time periods, which were not significantly different from each other. Significantly more egg clutches per hour were laid during hours of daylight as compared to hours of darkness. Significantly more egg clutches were laid in the top 1 m of the water column than at the bottom, and this was consistent throughout all 3 time periods. It is suggested that the increase in egg-laying activity during daylight hours may be due to a higher motivation to search for hosts during the night and an increased ability to locate silhouetted egg-laying sites during the day. These data can provide information useful for egg removal and control strategies.


KEY WORDS: Argulus foliaceus · Freshwater fish louse · Egg-laying · Diel variation · Depth · Parasite · Rainbow trout


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Cite this article as: Harrison AJ, Gault NFS, Dick JTA (2007) Diel variation in egg-laying by the freshwater fish louse Argulus foliaceus (Crustacea: Branchiura). Dis Aquat Org 78:169-172. https://doi.org/10.3354/dao01863

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