Australian bass (Macquaria novemaculeata) spawning and juvenile movement
About Macquaria novemaculeata
Australian bass (Macquaria novemaculeata) are a high value target species for environmental flow assessment. The fish is primarily a freshwater species, but they migrate downstream to spawn in estuaries. They are found in coastal rivers of the east coast of Australia (south of the Mary River in Queensland).
Australian bass (Macquaria novemaculeata) requires suitable flow conditions to allow migration, spawning, hatching and recruitment. Migration is triggered by flow above a set threshold for a given number of days during the correct season. Spawning happens after a migration event occurs, and is effected by temperature, salinity and season. Hatching occurs in a defined range post spawning, given temperature and salinity conditions are met. Finally, recruitment occurs after an extended period post hatching, given a flow recruitment is met.
The purpose of the model is to identify recruitment success for Australian bass (Macquaria novemaculeata). This success is scored daily, and is achieved if a number of hydrological rules have been met from a given day. This model produces a range of daily intermediate results, detailing which rules failed on that day, preventing a recruitment opportunity.
This model, describing the flow, temperature, salinity and seasonal requirements for Australian bass spawning, has been developed using quantitative information from the literature and expert opinion.
This model and its default parameters were created for application in South East Queensland.
However, the model parameters could be edited to suit other locations or species with similar requirements.
A recruitment opportunity occurs if the following rules are met:
- Migration event – Daily flow above a set threshold (1814 ML) during the set season (June-Sep) for a set duration (6 days)
- Spawning event – Daily temperature in set range (11-24) and daily salinity in set range (0 – 14) for 1 day anytime after migration but within the set season
- Hatching window – Daily temperature in set range (11-24) and daily salinity in set range (15 – 35) for 1 day within a set window (3-10 days) after spawning
- Upstream recruitment – Daily flow below a set threshold (432 ML) for 1 day after a minimum of a set number of days (40) since hatching and before the end of the year (defined by an overall season).
This model produces binary daily results (daily spawning success). These results are then aggregated to a yearly result, and then further to a temporal result based on the defined assessment parameters.
The temporal results are then analysed across locations to report an overall landscape risk by considering the simultaneous occurrence of failures across the system.
- Daily flow data
- Daily temperature data
- Daily salinity data
- Season – Overall season to partition the data into. Usually annual or water year.
- Migration – Parameters to inform migration success. Includes migration season, flow threshold, and duration.
- Spawning – Parameters to inform spawning success. Includes spawning season, temperature range and salinity range.
- Hatching – Parameters to inform hatching success. Includes temperature range, salinity range and time since spawning range.
- Recruitment – Parameters to inform recruitment success. Includes time since hatching and flow threshold.
- Daily time series of recruitment opportunities and reasons for failure
- Yearly time series of recruitment opportunities (>= 1 recruitment opportunity within the defined season)
- Yearly time series of assessment results
- Temporal time series of assessment results
- Spatial time series of assessment results
This plugin is written in Python and its underlying code is publicly available from the Eco Risk Projector computation repository.