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Ovarian weight was reduced by 6.3% when preserved in 10 % formalin solution. The affectsof freezing were negligible, resulting in a slight increase of 0.14 % in weight (Figures 2 and3). Relationships between fresh, preserved and frozen gonads were:Fresh weight (g) = 1.0452 x formalin preserved weight (g) (r 2 = 0.9985, n = 144)Fresh weight (g) = 0.9986 x frozen weight (g) (r 2 = 0.9973, n = 45)Comparison of the diameter of oocytes measured from anterior, middle and posterior regionsof the lobe (Table 4), and between left and right lobes (Table 5), show that ovariandevelopment was generally similar throughout the gonad. In most cases, the size of the mostmature stage oocytes did not differ between region of the lobe, and in all cases the maturitystage of the most advanced oocyte was the same in each region. Estimates of batch fecundityfor samples taken from anterior, middle and posterior regions of the lobe, and between leftand right lobes, also showed that final maturation of oocytes was similar throughout thegonad (Table 6).Table 4.Results of t-tests for dependent samples to compare the circumferences of 25 of themost mature stage oocytes within three locations of one ovarian lobe. Ant; anteriorportion of the lobe. Mid; middle portion of the lobe. Post; posterior portion of the lobe.CAS; Cortical alveoli stage. PNS; Perinucleolus stage. YGS; Yolk globule stage. Refer toMethods for sampling details.Ovary Sample Source Most Mature Oocyte df t P1 Ant v Mid Ant = CAS 24 1.1357 0.2673Ant v Post Mid = CAS 24 -0.7343 0.4699Post v Mid Post = CAS 24 -1.3873 0.17812 Ant v Mid Ant = PNS 24 2.7691 0.0106*Ant v Post Mid = PNS 24 -2.2551 0.0335*Post v Mid Post = PNS 24 -5.9050 0.0000*3 Ant v Mid Ant = CAS 24 1.1094 0.2783Ant v Post Mid = CAS 24 -0.4997 0.6219Post v Mid Post = CAS 24 -1.2231 0.23324 Ant v Mid Ant = YGS 24 -1.4135 0.1704Ant v Post Mid = YGS 24 -2.4945 0.0199*Post v Mid Post = YGS 24 -1.4531 0.15915 Ant v Mid Ant = CAS 24 -1.4581 0.1578Ant v Post Mid = CAS 24 -0.8407 0.4088Post v Mid Post = CAS 24 0.7835 0.44106 Ant v Mid Ant = CAS 24 1.1426 0.2645Ant v Post Mid = CAS 24 0.4368 0.6662Post v Mid Post = CAS 24 -0.7749 0.44607 Ant v Mid Ant = YGS 24 -1.3066 0.2037Ant v Post Mid = YGS 24 -0.1306 0.8972Post v Mid Post = YGS 24 0.7338 0.470210 Fish. Res. Rep. West. Aust.2001, 136, 1-32
Table 5.Results of t-tests for dependent samples to compare the circumferences of 25 of themost mature stage oocytes within the mid-region of each ovarian lobe. CAS; Corticalalveoli stage. MNS; Migratory nucleus stage. PNS; Perinucleolus stage. YGS; Yolkglobule stage. Refer to Methods for sampling details.Ovary Most Mature Oocyte df t PLeft Lobe Right Lobe1 YGS YGS 24 2.5984 0.0158*2 CAS CAS 24 -0.9837 0.33513 CAS CAS 24 0.6883 0.49794 CAS CAS 24 0.1623 0.87245 CAS CAS 24 -1.8283 0.08006 PNS PNS 24 2.4577 0.0216*7 MNS MNS 24 3.083 0.0051*8 MNS MNS 24 1.7420 0.0943Table 6.Results of t-tests for dependent samples to compare estimates of batch fecundity forS. commerson ovaries. Samples used in comparisons were taken from three regionsalong the ovarian lobe (anterior, middle and posterior), and from right and left lobes.Refer to Methods for sampling details.Sample Source df t PAnterior v Middle 17 -0.3217 0.7516Anterior v Posterior 17 -0.2780 0.7844Middle v Posterior 17 0.1539 0.8795Middle Left v Middle Right 7 -0.5498 0.59953.1 Staging system for microscopic analysis of formalinpreserved, histologically prepared gonad sectionsDescriptions of the developmental stages used in analysis of histologically prepared gonadsamples are provided in Table 7. Photographs of the ovarian stages are also provided inPlates 1 to 24. The stages in this system follow the development of the gonad from theundifferentiated juvenile state to the immature virgin and reproductively mature gonad, andthen through the annual reproductive cycle of the mature gonad.3.1.1 OvariesA conceptual diagram of the reproductive status for each ovarian stage in Table 7 is given inFigure 4. In this diagram, the juvenile (J) and virgin (F1) gonads have relatively lowreproductive status. This is also the case for the mature ovary when in the resting (F2) stage,until early signs of reproductive activity during the developing (F3) stage mark a rise in thereproductive status of the gonad. Within the period of reproductive activity, as marked by thepresence of developed (F4) ovaries, the reproductive status is relatively high, with short-termpeaks occurring during the brief periods when final maturation of the oocytes takes place(F5a) and spawning (F5b) occurs. This is followed by a drop in reproductive status duringthe brief post-spawning (F5c) stage back to the developed stage. However, if repeatspawning occurs over a short period of time (e.g. on consecutive days), then several peaks inFish. Res. Rep. West. Aust. 112001, 136, 1-32
Page 1 and 2: FISHERIES RESEARCH REPORT NO. 136,
Page 3 and 4: ContentsPageAbstract ..............
Page 5 and 6: Assessment of gonad staging systems
Page 7 and 8: commerson stocks within WA waters.
Page 9 and 10: were thawed in freshwater prior to
Page 11 and 12: the lamellae the estimate of batch
Page 13: Table 2.Descriptions used to catego
Page 17 and 18: 3.1.2 TestesS. commerson testes are
Page 19 and 20: F5b (Spawning/Running Ripe)F5c (Pos
Page 21 and 22: wrongly called F1, mainly because c
Page 23 and 24: Table 8.Simplified macroscopic stag
Page 25 and 26: 1 1a 2 3 4 5a 5c 610014 60 4 54 143
Page 27 and 28: similar data for the tropical snapp
Page 29 and 30: 5.0 AcknowledgementsThe assistance
Page 31 and 32: 7.0 AppendicesAPPENDIX A. Field sam
Page 33 and 34: F5b (Spawning)F5c (Post-spawn)F6 (S
Page 35 and 36: APPENDIX D. Fecundity analysis work
Page 37 and 38: List of PlatesABPlate 1.In situ vie
Page 39 and 40: CA*Plate 7.Whole and sectioned view
Page 41 and 42: CAPlate 9.Whole and sectioned views
Page 43 and 44: *YGPlate 12. Whole and sectioned vi
Page 45 and 46: HyHyPlate 18. Sectioned views of th
Page 47 and 48: Plate 21. Whole views of pre-spawni

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