The Role of Water Temperature Modelling in the Development of a Release Strategy for Cyprinid Herpesvirus 3 (CyHV-3) for Common Carp Control in Southeastern Australia

Klaus D Joehnk,Ashmita Sengupta,Yun Chen,Peter A Durr,Santosh K Aryal,Kerryne Graham,Linda Merrin

doi:10.3390/w12113217

Abstract

The common carp (Cyprinus carpio) is an invasive species in the rivers and waterways of southeastern Australia, and it has been implicated in the serious decline of many native fish species. Over the past 50 years, various control options have been explored, and to date, these have been ineffective or cost-prohibitive. Most recently, cyprinid herpesvirus 3 (CyHV-3) has been proposed as a biocontrol agent because of its high specificity and mortality rate. However, the virus is known to be only effective in a permissive water temperature range of approximately 16–28 °C. To define when this occurs, we undertook a hydrological reconstruction of five diverse river catchments (>130,000 km2) of southeastern Australia over three decades. This confirmed, in the studied areas, that while water temperatures are permissive from spring through to autumn, the time of year that this starts and ends is highly variable, interannually, and with strong latitudinal and altitudinal gradients between and within catchments. The results show that the virus should be effective with respect to water temperature throughout the water temperature range that carp occur in most of southeastern Australia. However, detailed water temperature estimation would still be required to determine the exact week of the start of release in any given catchment. Referring to observations in wild carp populations, we point out the limitation of developing a “release strategy” based solely on water temperature modelling and the need to incorporate fish biology and ecology into this planning.

Highlights

Common carp (Cyprinus carpio, hereafter referred to as carp) was originally introduced in southeastern Australia in the nineteenth century, it was not until the 1970s that it became widespread and by the 1980s it was accepted as a serious invasive species [1]
The number of reaches was highly correlated with the river length (Pearson’s r = 0.95), and the highest number was in the Lachlan (n = 502) and the lowest number was in the Glenelg (n = 53)
The results of the hydrological reconstruction across five distinct regions in southeast Australia highlight the large variability in connectivity, flow, and water temperature in both space and time

Summary

Introduction

Common carp (Cyprinus carpio, hereafter referred to as carp) was originally introduced in southeastern Australia in the nineteenth century, it was not until the 1970s that it became widespread and by the 1980s it was accepted as a serious invasive species [1]. This recognition followed surveys which showed that, in some parts of the Murray–Darling Basin (MDB), common carp comprised over. Whilst the role of carp as a cause or a consequence of ecosystem decline in the MDB is contentious, less so is the need to suppress the population of carp to achieve native fish recovery [6]. No wide-area control has been achieved, with commercial harvest, selective poisoning, genetic control, and physical separation proving either to be ineffective or cost-prohibitive [8]

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