Reproduction and growth of the winged pearl oyster, Pteria penguin (Röding, 1798) in the Great Barrier Reef lagoon

Milione, Michael (2011) Reproduction and growth of the winged pearl oyster, Pteria penguin (Röding, 1798) in the Great Barrier Reef lagoon. PhD thesis, James Cook University.

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Abstract

The thesis addressed various aspects of the reproductive biology and growth of the winged pearl oyster, Pteria penguin, in the Great Barrier Reef, north-eastern Queensland. The study was supported by the Australian Centre for International Agricultural Research (ACIAR), as part of ACIAR Project FIS/2006/172, 'Winged pearl oyster industry development in Tonga', for which James Cook University is the commissioned organization. The overall aim of this project was to provide information to support further development of P. penguin culture for pearl production, particularly as a basis for supporting livelihoods in Tonga and other developing countries.

P. penguin were collected at Orpheus Island, north-eastern Queensland to observe sexual development, sex ratio and changes in morphometric relationships during growth. P. penguin were found to be protandrous hermaphrodites, with all sexually mature oysters below 88.8 mm dorso-ventral measurement (DVM) being males. Evidence of male primary gonad development was seen in oysters with a DVM of ≥33.9 mm. Sexual maturity of males was first seen in oysters at ≥56.0 mm DVM, but was common in oysters at ≥70.0 mm DVM. Mean female size was 150.1 ± 3.6 DVM (mm ± 1 SE), and mean male size was 111.3 ± 2.2 mm DVM. In oysters <170 mm DVM, males outnumbered females. The female to male sex ratio in the population tended towards 1:1 with increasing size. Female to male sex ratio of oysters between 170-180 mm DVM was 1:1, and females outnumbered males in oysters >180 mm DVM. Significant linear correlations were found between antero-posterior measurement of the shell (APM) and DVM (r² = 0.97, p <0.001) and between shell thickness (ST) and DVM (r² = 0.95, p <0.001), and a curvilinear relationship was recorded between adductor muscle weight (AW) and DVM (r² = 0.93, p <0.001). These findings have industry applications relating to collection of juvenile stock, spawning induction procedures and determining optimal shell size for nucleus implanting.

The spawning cycle of P. penguin, was studied to observe seasonal changes in gonad development, mean oocyte diameter and sex ratio over time. A total of 201 oysters were collected over ten sampling periods, approximately every five to six weeks (mean = 20 oysters/sample). Gonad development stages for both males and females were identified as developing (with small follicles separated by connective tissue), ripe (swollen follicles containing fully developed eggs or sperm), spawning (partially empty follicles with walls partly broken), and spent (almost empty follicles with no signs of gametogenesis present). Oysters during periods of quiescence were described as inactive (with mainly connective tissue present and sex not distinguishable). Histological analysis of gonads showed that spawning activity occurred mainly through the austral mid-spring to late summer (November to March), when mean monthly water temperature ranged between 27.5–29.4 ºC. There was a primary spawning peak at the beginning of the spawning season in December, followed by a secondary peak in March. Mean oocyte diameter (μm) was highest during the warmer months, ranging from 31.2 ± 2.4 in November, to 36.2 ± 3.2 in March, and sex ratio analysis showed the percentage of females in the population also peaked between 30- 50% during this period.

Recruitment of P. penguin spat in relation to season, substrate type and depth was investigated over a period of 27 months, from February 2008 to April 2010. Two substrate types (70 % shade cloth and open weave polypropylene mesh bags) were deployed at two depths (4 m and 6 m) and checked every six weeks over three spawning seasons to determine any differences in quantity of spatfall between these factors. No significant difference was found in spat recruitment between substrate types (p = 0.158) or depth (p = 0.349), while there was a significant seasonal effect on spat recruitment (p < 0.001), with a peak in the quantity of spatfall in late summer, from February to March, and no spat collected in the winter to spring (July to October). Maximum settlement of spat was 10.2 per mesh bag collector in February 2008. Recruitment was significantly reduced (p < 0.001) during the 2010 spawning season due to disturbance from severe storms generated by tropical cyclone Olga in late January.

Juvenile P. penguin were cultured for six months in three commonly used culture units (panel pocket nets, plastic mesh trays and pyramidal pearl nets) at two dissimilar sites, Pioneer Bay (a coral reef environment in which P. penguin are naturally present) and Cape Ferguson (a coastal semi-estuarine area with high levels of silt deposition), to determine the effects of site and culture method on growth, survival and fouling. Mean growth increases (mm) were recorded for DVM, APM, ST and WW (whole weight, g). At Pioneer Bay, five replicates for each of the three culture unit types were suspended at 3 m and at 6 m, and mean initial DVM was 28.0 ± 0.6 mm (n = 190). At Cape Ferguson, there were five replicates for each culture unit at 3 m only, and mean initial DVM was 28.0 ± 0.6 mm (n = 86). Mean growth increase at the end of the experiment for oysters at Pioneer Bay and Cape Ferguson (respectively) were: 26.6 ± 1.0 and 32.6 ± 2.4 mm DVM, 29.6 ± 1.2 and 34.0 ± 2.9 mm APM, 6.7 ± 0.3 and 9.7 ± 0.5 mm ST, and 16.5 ± 0.7 and 23.0 ± 2.1 g WW. For all growth parameters, mean increase was significantly higher under high turbidity conditions at Cape Ferguson (p < 0.05). Culture unit also affected growth, with oysters held in mesh trays showing significantly higher growth at both sites (p < 0.05). Mean survival of oysters at Cape Ferguson (96.5%) was significantly higher than at Pioneer Bay (79.4%). Depth had no significant effect on growth, survival or fouling. The results indicated that site selection and culture unit are important parameters for optimizing growth and survival during nursery phase culture of P. penguin.

Growth of P. penguin was monitored over 20 months, from April 2009 to November 2010, to investigate differences in growth performance at three dissimilar sites; Pioneer Bay, Cape Ferguson and Horseshoe Bay in the Great Barrier Reef lagoon. Growth parameters generated with the von Bertalanffy growth function ranged from K = 0.09 - 0.32 and L∞ = 283.6 - 822.5 (mm DVM). Overall growth performance (Φ') ranged between 4.40 - 4.77 and time to reach commercial size (T₁₀₀) was between 1.38 - 1.54 years, and T₁₂₀ was between 1.74 - 1.92 years. A more accurate estimate of L∞ = 213.4 mm DVM was obtained at Pioneer Bay by using larger data set which incorporated a wider size range of oysters. Overall monthly increase in DVM of oysters held at Horseshoe Bay (5.3 ± 0.2 mm) was significantly higher (p < 0.05) than those at Pioneer Bay (4.8 ± 0.1 mm) and Cape Ferguson (4.9 ± 0.1 mm), which were not significantly different. Monthly DVM increase was fastest (7.2 ± 0.1 mm), in small oysters (50 - 70 mm DVM) in the spring-summer and was lowest (2.2 ± 0.4 mm) in larger oysters (105 - 110 mm DVM) during the spring. Regression analysis showed APM, ST and WW were significantly correlated with DVM for all groups (p < 0.001). In the DVM size class of 100-120 mm, mean WW of oysters at Cape Ferguson was significantly higher (p < 0.01), and APM:DVM ratio was also significantly higher (p < 0.01) for oysters at Cape Ferguson and Horseshoe Bay, while the there were no significant differences between groups in ST:DVM ratio. At all three sites, the highest mortalities (%) were recorded for small oysters (25-50 mm DVM) during the winter period. Suspended inorganic matter (PIM, g) levels were significantly different between sites (p < 0.001). Overall results show that P. penguin are able to tolerate and even thrive under a wide range of turbidity levels. However, site selection must consider the risk of exposure to low salinity and turbulent wave action, which may have negative impacts on growth. Comparison between growth rates obtained in the study demonstrate that there is significant variability in growth between sites in the Great Barrier Reef lagoon.

Item ID: 40091
Item Type: Thesis (PhD)
Keywords: aquaculture; Cape Ferguson; environment; fouling; gametogenesis; GBR; gonad development; Great Barrier Reef lagoon; Great Barrier Reef Marine Park; Great Barrier Reef; growth; Magnetic Island; modelling; nursery culture; oocyte; Orpheus Island; pearl culture; pearl oyster; pearls; Pteria penguin; Queensland; recruitment; reproduction; reproductive biology; sex ratio; shell dimensions; spat; spawning; survival; winged pearl oyster
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Additional Information:

Publications arising from this thesis are available from the Related URLs field. The publications are:

Chapter 2: Milione, Michael, Saucedo, Pedro, and Southgate, Paul (2011) Sexual development, sex ratio and morphometrics of Pteria penguin (Bivalvia: Pteriidae), in north-eastern Australia. Molluscan Research, 31 (1). pp. 30-36.

Chapter 3: Milione, Michael, and Southgate, Paul C. (2012) Reproductive cycle of the winged pearl oyster, Pteria penguin (Röding 1793) (Pteriidae) in north-eastern Australia. Invertebrate Reproduction and Development, 56 (2). pp. 164-171.

Chapter 4: Milione, Michael, and Southgate, Paul (2011) Seasonal changes in recruitment of Pteria penguin in North Queensland, Australia. Journal of Shellfish Research, 30 (1). pp. 89-94.

Chapter 5: Milione, Michael, and Southgate, Paul (2011) Environmental conditions and culture method effects on growth and survival of juvenile winged pearl oyster, Pteria Penguin. Journal of Shellfish Research, 30 (2). pp. 223-229.

Chapter 6: Milione, Michael, and Southgate, Paul (2012) Growth of the winged pearl oyster, Pteria penguin, at dissimilar sites in northeastern Australia. Journal of Shellfish Research, 31 (1). pp. 13-20.

Date Deposited: 03 Sep 2015 03:41
FoR Codes: 07 AGRICULTURAL AND VETERINARY SCIENCES > 0704 Fisheries Sciences > 070401 Aquaculture @ 100%
SEO Codes: 83 ANIMAL PRODUCTION AND ANIMAL PRIMARY PRODUCTS > 8301 Fisheries - Aquaculture > 830104 Aquaculture Oysters @ 100%
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