Redthroat Emperor Lethrinus miniatus

Bonnie Holmesa, David Faircloughb and Stephen Newmanb

Redthroat Emperor

Table 1: Stock status determination for Redthroat Emperor



Western Australia


East Australian

West Australian (GDSMF, PDSF, WCDSIMF)

Stock status






Catch, catch rate, length frequencies, age frequencies, mortality estimates


CRFFF = Coral Reef Fin Fish Fishery (Queensland); GDSMF = Gascoyne Demersal Scalefish Managed Fishery (Western Australia); PDSF = Pilbara Demersal Scalefish Fisheries (Western Australia); WCDSIMF = West Coast Demersal Scalefish (Interim) Managed Fishery (Western Australia)

Stock Structure

Genetic analysis suggests that there are two separate biological stocks of Redthroat Emperor in western and eastern Australian waters1. Hence, reporting is undertaken at the biological stock level.

Stock Status

East Australian biological stock

The most recent assessment of the Redthroat Emperor biological stock2 analysed fishery data using an age-structured model that incorporated all available information on catch, catch per unit effort and age structure. The model estimated that biomass in 2004 was approximately 70 per cent of the unfished (1946) level. The biological stock is not considered to be recruitment overfished.

The assessment also indicated that commercial catch has been well below the current total allowable commercial catch (TACC) (700 tonnes [t]) each year since the TACC was set in 2006; only 43 per cent of the quota was taken in the 2009–10 season. This level of fishing mortality is unlikely to cause the biological stock to become recruitment overfished.

On the basis of the evidence provided above, the biological stock is classified as a sustainable stock.

West Australian biological stock

No stock assessment has been completed. Insufficient information is available to confidently classify the status of this biological stock; as a result, the biological stock is classified as an undefined stock.

Table 2: Redthroat Emperor biology1,3–4

Longevity and maximum size

20 years; 65 cm TL

Maturity (50%)

Females: ~31 cm TL

TL = total length

Figure 1: Distribution of reported commercial catch of Redthroat Emperor in Australian waters, 2010
Figure 1: Distribution of reported commercial catch of Redthroat Emperor in Australian waters, 2010

Main features and statistics for Redthroat Emperor stocks/fisheries in Australia in 2010
  • Redthroat Emperor is predominantly taken using line fishing methods, with small trapping operations also occurring in the Pilbara, Western Australia.
  • A range of input and output management controls have been implemented across the fisheries in Queensland and Western Australia:
    • Input controls include limited entry, spawning closures, area closures, gear restrictions and effort restrictions.
    • Output controls include TACCs, size limits, and bag and possession limits.
  • In the Coral Reef Fin Fish Fishery (Queensland), 188 commercial vessels caught Redthroat Emperor in 2009–10. In Western Australia, 60 vessels caught Redthroat Emperor in 2009–10.
  • The total amount of Redthroat Emperor commercially caught in 2009–10 was 326 t, comprising 267 t in Queensland and 59 t in Western Australia. In Queensland, approximately 81 t was also caught in the charter sector. The last recreational estimate from a state-wide survey, which was conducted in 2005, found that 89 000 fish were recorded5. The only estimate of Indigenous harvest, from the 2001 national survey, is approximately 9000 individual emperors (including emperor species other than Redthroat Emperor)6.

Figure 2: Commercial catch of Redthroat Emperor in Australian waters, 2000–10
Figure 2: Commercial catch of Redthroat Emperor in Australian waters, 2000–10
Note: Queensland catch estimates are by financial year (e.g. 2010 refers to 2009–10 data).

Catch Explanation

The eastern Australian commercial catch of Redthroat Emperor increased to around 267 t, or 43 per cent of available quota, in 2009–10. Logbook estimated landings showed a slight increase in catch and catch rate in 2009–10, but the commercial quota remains significantly undercaught. This is likely to reflect the relatively low value of Redthroat Emperor (compared with Coral Trout) and the lower market demand. The catch decline from 2004–05 occurred when new management arrangements were implemented in Queensland (through the Coral Reef Fin Fish Fishery Management Plan 2003), which effectively reduced the effort applied to the fishery to approximately half its previous level. The individual transferable quota system for coral reef–associated species was also introduced at this time.

The total commercial catch of Redthroat Emperor in Western Australia in 2009–10 was 59 t, similar to that reported in 2008–09. The catch over the past two years is less than half the average catch for the preceding three years (2005–06 to 2007–08). This decrease is primarily due to the commercial line fishery in the West Coast Bioregion becoming formally managed in 2008, with the aim of reducing effort and thus catch by at least 50 per cent7.

Effects of fishing on the marine environment
  • Beyond the removal of fish, there is little evidence to suggest that the fisheries targeting. Redthroat Emperor impact significantly on the marine environment.

Environmental effects on Redthroat Emperor
  • Coral bleaching events (see Hoegh-Guldberg et al.8) and changes in ocean chemistry have the potential to impact on the replenishment rates of coral reef fin fish populations9, individual growth rates and spawning output10.

a Department of Agriculture, Fisheries and Forestry, Queensland
b Department of Fisheries, Western Australia