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Data on sexual reproduction of scleractinian coral species living in temperate zones, particularly in the Mediterranean Sea, are quite scarce. This paper describes sexual reproduction of the colonial coral Cladocora caespitosa from Veliko jezero (Mljet Island) in the Adriatic Sea. Spawned orange eggs and white sperm bundles were observed on the coral bank of C. caespitosa two nights before the full moon (20 June 2005) coinciding with increasing water temperature and correlated with the lunar cycle. Spawning was observed during five nights, involving about 30% of the colonies from the coral bank. Different colonies on the bank released only one type of gamete during the reproductive period. The diameter of the sperm bundles ranged from 100 to 200 μm (average 163 μm; SD = 47.08), while the female gametes diameter ranged from 300 to 500 μm (average 416 μm; SD = 73.12). [ABSTRACT FROM AUTHOR]

The rapid decline of Acropora cervicornis and Acropora palmata has often been linked with coral reef deterioration in the Caribbean; yet, it remains controversial whether these species are currently recovering or still declining. In this study, the status of ten populations of A. palmata in Los Roques National Park (LRNP), Venezuela is presented. Six of these populations showed signs of recovery. Ten 80 m2 belt-transects were surveyed at each of the ten reef sites. Within belt-transects, each colony was measured (maximum diameter and height) and its status (healthy, diseased or injured) was recorded. Populations in recovery were deWned by a dominance of small to mediumsized colonies in densities >1 colony per 10 m2, together with 75% undamaged colonies, a low prevalence of diseases (<10%), and a low density of predators (0.25 snails per colony). Based on allozyme analysis of seven polymorphic loci in four populations (N = 30), a moderate to highgenetic connectivity among these populations (FST = 0.048) was found with a predominance of sexual over asexual reproduction (N* : N = 1; Ngo : N = 0.93-1). Both ecological and molecular data support a good prognosis for the recovery of this species in Los Roques. [ABSTRACT FROM AUTHOR]

Broadcast spawning of gametes with planktonic development of larvae is the most common reproductive mode in tropical corals, and is generally thought to optimize the dispersal potential of larvae. To this end, many previous studies of coral larval dispersal have focused on the maximum time larvae can remain competent to settle and consequently how far they might disperse. However, dispersal ability of broadcast-spawned coral larvae will be linked, at least in part, to the minimum time to settlement competency as well as the length of the planktonic period—although estimates of minimum time to competency remain largely anecdotal, with few rigorous studies of the pre-competent period. To determine the minimum time to larval settlement in two species of broadcast-spawning coral ( Platygyra daedalea and Goniastrea favulus), we monitored larval settlement rates in aquaria every 6 h from the time larvae commenced swimming (i.e. were ciliated, fully developed larvae) for a period of approximately 10 days. For P. daedalea, peak settlement occurred between 60 and 66 h following fertilization (2.5 and 2.75 days), which is markedly earlier than the 4- to 6-day time period commonly cited as the minimum time before broadcast-spawned coral larvae are competent to settle. Surprisingly, it was also clear from our experimental results that settlement in P. daedalea occurred as a distinct pulse during the 60- to 66-h period, rather than continuously throughout the study period. G. favulus larvae also appear to be able to settle quickly (from 54 h following fertilization). We argue, on the basis of these short competency times and apparently rapid settlement, that dispersal in broadcast-spawning coral larvae may not be as great as has previously been assumed. [ABSTRACT FROM AUTHOR]

We document long-term effects of a simulated bleaching event on the reproductive output and offspring viability of the soft coral Lobophytum compactum. Corals were subjected to temperature and solar radiation treatments to produce both moderately (48-60%) and heavily (90-95%) bleached colonies. Although bleached colonies recovered their zooxanthellae within 10 to 18 weeks, impacts on reproductive output were significant for at least two annual spawning seasons. In the first year, both polyp fecundity and mean oocyte diameter were reduced and inversely correlated with the degree of bleaching, with complete failureof fertilization in the group of heavily bleached colonies. For moderately bleached soft corals, survival and growth of sexual offspring did not differ significantly from those of unbleached colonies. Although no further reductions in zooxanthellae densities in experimental soft corals were recorded throughout the subsequent second year, egg size and fecundity of the heavily bleached soft corals were still significantly reduced 20 months later. Severe bleaching clearly has long-term sub-lethal impacts, reducing overall reproductive output for atleast two spawning seasons. [ABSTRACT FROM AUTHOR]