Poor gill health remains among the main reasons for reduced growth and increased mortality of farmed salmon. Alongside diseases such as AGD, cnidarian stinging cells from both jellyfish and hydroids can pose a risk to gill health. The stinging cells are released into the water as a result of farm operations such as net cleaning and have been shown to result in impaired gill function.
Although gill damage can be detected through histology, it is not always easy to identify the cause. There is therefore a need for new diagnostic tools that can be used in addition to histological sampling. Identification of the cause for gill injury can be used to trigger operational responses, including mitigation measures, and changes in on-farm practices to limit extent and impact.
One possible approach is the use of swab samples combined with genetic analysis (PCR), which is already used to diagnose e.g. amoebic disease. Such sampling is non-destructive and therefore has an advantage over lethal sampling techniques for histological analyses.
Aim
The main objective of the project is to develop a non-lethal PCR based assay that can detect and quantify stinging cells in gill mucus swabs and water samples.
Since hydroids (Ectopleura larynx) occur regularly on aquaculture nets, sample material can easily be obtained, and the species can therefore be used as a model. The assay will be tested in an exposure trial in tanks.
The subgoals of the project are:
1. Develop an qPCR assay based on the genetic information of E. larynx sampled in Norway.
2. Verify the developed qPCR assay in an exposure experiment with Atlantic salmon.
Project organisation
The project is a collaboration between SINTEF Ocean, Pharmaq Analytic AS and NMBU.
The project is led by Dr. Nina Bloecher (SINTEF Ocean). Other participants are Dr. Roman Netzer and Dr. Deni Ribicic from SINTEF Ocean, Dr. Kai-Inge Lie from Pharmaq analytic and Dr. Liv Østevik from NMBU.
The project is split into 3 work packages:
WP1: Dissemination and administration
WP2: Development of the PCR assay for detection of hydroid material
WP3: Exposure trial