Cleaner shrimp remove parasite eggs on fish cages

AS Grutter,KS Hutson,DB Vaughan

doi:10.3354/aei00280

Abstract

Benthic stages of cultured fishes' ectoparasites are a major contributor to persistent reinfections in aquaculture. These stages are resistant to chemical therapies and are costly to manage in terms of time and labour. Cleaner shrimp, unlike cleaner fishes, prey on benthic stages, suggesting they have the potential to reduce parasite reinfection pressure without having to be in direct contact with the client fish. Cleaner shrimp have never been used as biocontrols in commercial aquaculture, but offer an advantage over cleaner fishes in that they are not susceptible to the ectoparasites of their clients. We present the first investigation of a cultured cleaner shrimp, Lysmata vittata, as a biocontrol agent against the eggs of the economically important cosmo politan ectoparasite Neobenedenia girellae infecting cultured juvenile grouper, Epinephelus lanceolatus, under simulated recirculating aquaculture conditions. L. vittata removed the eggs of N. girellae entangled on the mesh of the culture cages and significantly reduced N. girellae recruitment to fish by similar to 87%. Our results demonstrate the value of cleaner shrimp in addressing ectoparasite problems and highlight the importance of investigating novel biocontrol strategies in aquaculture.

Highlights

Biocontrols are living organisms used to suppress the density of a pest organism’s population or its associated impact, rendering it less abundant and less problematic (Eilenberg et al 2001)
We constructed 3 mixed effects randomintercept models; 2 with correlation of variance structures for variance differences in treatment, or treatment−day combination groups, and 1 without a Lysmata vittata consumed Neobenedenia girellae eggs entangled on the oyster mesh fish cages (Fig. 3) and subsequently reduced N. girellae recruitment by ~87% (ANOVA: F1,6 = 173.36, p < 0.0001; Fig. 4)
Our results demonstrate for the first time the potential of the cleaner shrimp Lysmata vittata as an effective biocontrol agent under simulated recirculating marine aquaculture conditions, and its potential for use on fish farms

Summary

Introduction

Biocontrols are living organisms used to suppress the density of a pest organism’s population or its associated impact, rendering it less abundant and less problematic (Eilenberg et al 2001). Aquacult Environ Interact 10: 429–436, 2018 the introduction of indigenous natural predators to control pest organisms (see Atalah et al 2015) This strategy offers clear benefits in salmon farming by reducing numbers of reproductive adult sea lice. Recent evidence suggests that cleaner fishes, including lumpfish, are susceptible to other more generalist pathogens important to salmon and other fishes, including C. elongatus, and Paramoeba perurans (Young, Crosbie, Adams, Nowak & Morrison, 2007) sensu Feehan et al (2013), the aetiological agent of amoebic gill disease (Karlsbakk et al 2013, 2014, Karlsbakk 2015, Haugland et al 2017, Powell et al 2017) This demonstrates a clear risk of using a cleaner fish model against the pathogens of other fishes, and the limited scope for using cleaner fishes against other host−parasite models and in other geographical regions

Objectives

Results

Conclusion