Patterns of reproduction in two co-occurring Great Barrier Reef sponges

2017 ◽  
Vol 68 (7) ◽  
pp. 1233 ◽  
Author(s):  
Muhammad Azmi Abdul Wahab ◽  
Rocky de Nys ◽  
Ross Holzman ◽  
Caroline Luise Schneider ◽  
Steve Whalan

Reproduction is a key biological process that underpins the persistence and maintenance of populations. However, information on the reproductive biology of Great Barrier Reef (GBR) sponges is depauperate. The present study established the reproductive biology of two co-occurring GBR sponges, namely Ianthella basta (Verongida) and Ircinia sp. (Dictyoceratida). Sponges were haphazardly sampled (monthly) over a period of 1 year. Histological analysis of samples established the sexuality, development, seasonality, gametogenesis and fecundity of the two species, as well as the effects of temperature on reproduction. I. basta is oviparous, whereas Ircinia sp. is viviparous. The mode of sexuality in I. basta could not be determined, because male propagules were not detected, whereas Ircinia sp. is a simultaneous hermaphrodite. Reproduction in I. basta is unique within the verongids and co-occurring oviparous species, with peak reproduction occurring at the minimum annual temperature (23°C) and spawning occurring as the temperature increased above 23.4°C. Reproduction in Ircinia sp. corresponded to patterns reported for other viviparous GBR species, with an increase in reproductive propagules, peak sperm release, fertilisation and spawning occurring at temperatures above 25°C. Fecundity in I. basta and Ircinia sp. is high compared with other sponge species in the region, which may contribute to their apparent abundance on the GBR.

2005 ◽  
Vol 208 (1) ◽  
pp. 69-76 ◽  
Author(s):  
Fredrik Pleijel ◽  
Greg W. Rouse

2006 ◽  
Vol 57 (4) ◽  
pp. 403 ◽  
Author(s):  
A. J. Williams ◽  
C. R. Davies ◽  
B. D. Mapstone

Uniformity in fish population biology is a common assumption in many fishery assessments and management arrangements. Although spatial patterns in population biology are often unknown, ignorance of significant variation within a fished stock has profound implications for fishery assessments and management. In the current paper, the reproductive biology of an exploited reef fish, Lethrinus miniatus, was examined for populations in the northern and southern regions of the Great Barrier Reef (GBR). Significant regional variation was observed in some reproductive parameters, but not others. In the northern region, the proportion of spawning females observed during the spawning season was significantly greater and the size at sex change significantly smaller than in the southern region. However, the spawning season, age at sex change and sex ratios did not differ significantly between the northern and southern regions. Size and age at maturity could not be estimated from either of these regions, but an estimate was obtained from the Capricorn–Bunker region at the southern tip of the GBR. The observed regional patterns in reproductive biology of L. miniatus populations have important implications for specific management arrangements such as size limits and seasonal closures, and for fisheries management in general.


2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Andrew H. Baird ◽  
James R. Guest ◽  
Alasdair J. Edwards ◽  
Andrew G. Bauman ◽  
Jessica Bouwmeester ◽  
...  

AbstractThe discovery of multi-species synchronous spawning of scleractinian corals on the Great Barrier Reef in the 1980s stimulated an extraordinary effort to document spawning times in other parts of the globe. Unfortunately, most of these data remain unpublished which limits our understanding of regional and global reproductive patterns. The Coral Spawning Database (CSD) collates much of these disparate data into a single place. The CSD includes 6178 observations (3085 of which were unpublished) of the time or day of spawning for over 300 scleractinian species in 61 genera from 101 sites in the Indo-Pacific. The goal of the CSD is to provide open access to coral spawning data to accelerate our understanding of coral reproductive biology and to provide a baseline against which to evaluate any future changes in reproductive phenology.


2013 ◽  
Vol 64 (4) ◽  
pp. 277 ◽  
Author(s):  
Alastair V. Harry ◽  
Andrew J. Tobin ◽  
Colin A. Simpfendorfer

Understanding the life history of an exploited fish species is an integral part of successful fisheries management and this information can be used in quantitative population assessments. The present study describes the quantitative relationships among age, growth and reproductive biology of two commercially exploited sharks from the Great Barrier Reef World Heritage Area (GBRWHA), namely, the spot-tail shark, Carcharhinus sorrah (n = 659) and the Australian blacktip shark, C. tilstoni (n = 512). Longevity estimates based on vertebral ageing were 9 and 14 years for male and female C. sorrah and 13 and 15 years for C. tilstoni. However, an age-validation study failed to validate annual banding in larger individuals, suggesting that maximum age may be underestimated by vertebrae. C. sorrah grew to adult size relatively fast, reaching maturity at 2.3–2.4 years, whereas C. tilstoni grew slower, reaching maturity at 5.2–6.1 years. For both species, however, reproduction did not commence until approximately a year after maturity, at 3.4 years for C. sorrah and 7.2 years for C. tilstoni. The results of the present study suggest that in the GBRWHA, C. tilstoni, in particular, begins reproducing at an older age and lives longer than previously thought.


Author(s):  
Regina Balogh ◽  
Kennedy Wolfe ◽  
Maria Byrne

Despite the important ecological roles of commercial bêche-de-mer holothuroids in coral reef ecosystems their reproductive biology is poorly studied, including on the Great Barrier Reef (GBR). We investigated reproduction of Stichopus herrmanni, a commercially important species listed as Vulnerable, at One Tree Island, southern GBR. Gonad index, histology and spawning observations indicated an annual reproductive cycle with gamete release in the Austral spring and summer (November–February), as for populations of this species at a similar latitude in New Caledonia. Stichopus herrmanni releases gametes episodically, spawning multiple times during summer. Assimilation of spawning observations from OTI and elsewhere along the GBR and tropical Pacific revealed that gamete release by S. herrmanni is influenced by the lunar cycle, with spawning taking place around the new moon in summer. This species is an aggregative spawner with a behavioural change to attain elevated positions on the reef at dusk prior to spawning. After the spawning season, gametes remaining in the gonads are reabsorbed. Spent gonads completely lacked gametes. There was a quiescence in gonad development in winter with an absence of gonads in some specimens, indicating an aestivation-like period for reproduction. By late-winter (August) recovery stage gonads were distinguished by the initiation of gametogenesis, which coincided with increasing temperature and day length. Our findings contribute to the understanding of the reproductive biology of S. herrmanni, a consideration for future fisheries management in the protection of this Vulnerable species, especially with respect to the increasing global trade in bêche-de-mer.


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