1. DEPARTMENT OF PRIMARY INDUSTRY, FISHERIES AND MINES Reproduction

2. DEPARTMENT OF PRIMARY INDUSTRY, FISHERIES AND MINES Establish the reproductive strategy of black jewfish. Aim

3. DEPARTMENT OF PRIMARY INDUSTRY, FISHERIES AND MINES 1.Determine the spawning season and the relevance of the annual aggregations. 2.Establish the size of sexually mature black jewfish (minimum and I 50 ). 3.Document the current size/age structure of black jewfish landings. Objectives

4. DEPARTMENT OF PRIMARY INDUSTRY, FISHERIES AND MINES Over a two year period, 70 fish per month were measured, weighed and sampled. Fish sourced from commercial fishers and fishing tour operator landings. Additional fish ( 130 cm) sourced from commercial and rec. fishers. General Methods

5. DEPARTMENT OF PRIMARY INDUSTRY, FISHERIES AND MINES Reproduction Study Methods Gonad sampling: –Individual lobes weighed; section of one lobe preserved. Gonad processing: –Sectioned and stained; Classified based on oocyte stages.

6. DEPARTMENT OF PRIMARY INDUSTRY, FISHERIES AND MINES Classification System StageMost advanced oocyteOther key criteria F1ImmatureChromatin nucleolar or perinucleolar Thin gonad wall; Brown bodies not present; Compact, well packed lamellae; May have atretic cortical alveoli oocytes. F2DevelopingCortical alveoli (yolk vesicle) May have atretic oocytes; May also have post-ovulatory follicles and brown bodies. F3DevelopedYolk globuleMay have atretic oocytes; May also possess brown bodies. F4Pre-spawningMigratory nucleusOvary appears disorganised; Brown bodies may be present; May have post-ovulatory follicles if fish has spawned already. F5SpawningHydratedOvary appears disorganised; Post-ovulatory follicles, brown bodies and atretic oocytes may be present. F6SpentAtretic vitellogenicLammellae disrupted and disorganised; Vasculated in late spent stage; Brown bodies generally present. F7RestingChromatin nucleolar or perinucleolar Thick gonad wall; Brown bodies common but not always present; Lammellae not compact, often vaculated.

7. DEPARTMENT OF PRIMARY INDUSTRY, FISHERIES AND MINES Mean GSI Relative gonadosomatic index and standard deviation for females (n = 529). Spawning Season

8. DEPARTMENT OF PRIMARY INDUSTRY, FISHERIES AND MINES F2 – Developing gonads Histological Results

9. DEPARTMENT OF PRIMARY INDUSTRY, FISHERIES AND MINES F3 – Developed gonads Histological Results

10. DEPARTMENT OF PRIMARY INDUSTRY, FISHERIES AND MINES F4 & F5 – Near spawning gonads Histological Results

11. DEPARTMENT OF PRIMARY INDUSTRY, FISHERIES AND MINES Histological Results F6 – Spent gonads

12. DEPARTMENT OF PRIMARY INDUSTRY, FISHERIES AND MINES F7 – Resting gonads Histological Results

13. DEPARTMENT OF PRIMARY INDUSTRY, FISHERIES AND MINES F2 Developing (July) F3 Developed (October) F6 Spent (February) F7 Resting (May) F4-5 Near Spawning (November) Histological Results

14. DEPARTMENT OF PRIMARY INDUSTRY, FISHERIES AND MINES Spawning Size Size at first maturity Minimum size of maturity = 85 cm Maximum size of immaturity = 100 cm I 50 estimate = ~90 to 95 cm. Need to run logistic model.

15. DEPARTMENT OF PRIMARY INDUSTRY, FISHERIES AND MINES Size Structure Length/weight of black jewfish harvested near Darwin, 2004-06 (n = 1490). Length (cm) Weight (kg)

16. DEPARTMENT OF PRIMARY INDUSTRY, FISHERIES AND MINES Size Structure Length/weight of black jewfish harvested near Darwin, 2004-06 (n = 1490). Length (cm) Weight (kg) Mature Fish

17. DEPARTMENT OF PRIMARY INDUSTRY, FISHERIES AND MINES Length/weight of black jewfish harvested near Darwin, 2004 (n = 415). Length (cm) Weight (kg) Length (cm) Size Structure

18. DEPARTMENT OF PRIMARY INDUSTRY, FISHERIES AND MINES Length/weight of black jewfish harvested near Darwin, 2005 (n = 636). Length (cm) Weight (kg) Size Structure

19. DEPARTMENT OF PRIMARY INDUSTRY, FISHERIES AND MINES Length/weight of black jewfish harvested near Darwin, 2006 (n = 438). Length (cm) Weight (kg) Length (cm) Size Structure

20. DEPARTMENT OF PRIMARY INDUSTRY, FISHERIES AND MINES Summary GSI indicates extended spawning = Aug to Jan. GSI and histology suggests serial spawning. Minimum size = 85 cm; I 50 = ~90-95 cm. No apparent difference in size between years.