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Marron and micronutrients/humic acid

Marron and micronutrients/humic acid

  • Author: SWCC
  • Date Posted: Jun 13, 2016
  • Category:

Project Details

Project Delivery: Marron Growers Association of WA

Contact: Wendy Wilkins (SWCC – Bridgetown).  Ph: 9761 4184

Email: wendy.wilkins@swccnrm.org.au

Website: SWCC Sustainable Agriculture

Start Date:  May 2016                     End Date: March 2018

Site ID:  IN2.1.012

Size Are Ha: 2.1ha

Project Aim

The project’s aims are to study the effects of the addition of pre-selected trace elements on natural
productivity and yield in juvenile marron (Cherax cainii) in farm ponds. Subsidiary aims are:

  • To study the effect of the addition of pre-selected trace elements on phytoplankton and
    zooplankton abundance.
  • To compare the effect of the addition of pre-selected trace elements on two life stages of
    marron (juvenile and grow-out stages).
  • To study the species diversity of phytoplankton and their role in marron survival and how
    this may affect specific growth rates.
  • To study the abundance and species diversity of zooplankton and their role in marron
    survival and how this may affect specific growth rates.

Methodology

The natural productivity of a number of ponds has been determined and the results show that the presence of various zooplankton species such as rotifers is higher in ponds with higher levels of manganese. This preliminary analysis of trace element concentrations of pond water and the natural productivity in those marron ponds indicates that the ponds having higher levels of manganese, calcium, silica and zinc tend to have elevated phytoplankton and zooplankton productivity as compared to other ponds. The available initial data is based on different life stages of marron (juveniles, grow-out and brooders), as well as on data from 10 grow-out monosex ponds (5 female and 5 male).

Based on this initial data from the marron ponds, the trial will be carried out to study the effect of trace elements on pond productivity in ponds with juvenile marron and others with grow-out marron.

Trial 1: There are eleven juvenile ponds and they will be treated as follows:

  1. Treatments 1 and 2: Three juvenile ponds treated with four selected trace elements (manganese, calcium, silica and zinc with different concentrations) at two concentrations each (total 6 ponds).
  2. Treatment 3: Three juvenile ponds treated with all 12 pre-selected trace elements.
  3. Two ponds will be used as controls.

Trial 2: Similarly, there are two monosex grow-out ponds (5 for males and 5 for females), which will be treated as follows:

  1. For these ponds, the treatment will be the use of selected trace elements (manganese, calcium, silica and zinc with different concentrations). Treatment will be the same for both male and female populations with triplicates.
  2. 2 control ponds for each sex.

Trial 3: There are nine brooder ponds to be used in this trial, which will be treated as follows:

  1. The first treatment will test the use of selected trace elements (manganese, calcium, silica and zinc) in triplicate (3 ponds).
  2. The second treatment will be with all pre-selected 12 trace elements, again in triplicate..
  3. Three ponds will be used as control.

The effect of trace element composition on growth and survival of marron will be compared at harvest for juvenile, male / female grow-out and brooder ponds.

Laboratory trials:

The growth and survival of marron will also be studied under laboratory conditions by using the same pre-selected trace elements. The culture of algae will be carried out in aquaria and the marron will be cultured to calculate growth and survival of marron. The treatments are the same for the laboratory experiments to observe the effect of addition of trace elements on growth of algae and marron under more controlled conditions.

Curtin University is a partner in this project.

*Join the growing number of farmers and industry advisers receiving trial updates by subscribing to SWCC’s Sustainable Agriculture E-newsletter.  Simply email wendy.wilkins@swccnrm.org.au with “Subscribe to SWAG” as the subject.

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