Regional and species specific sexual reproductive patterns of three zooxanthellate scleractinian corals across the Eastern Tropical Pacific

Abstract

Sexual reproduction of zooxanthellate scleractinian corals in the Eastern Tropical Pacific (ETP) is influenced by the interactive effects of regional and local oceanographic conditions, as well as a variety of other environmental factors. Differences in spatial and temporal gamete development and reproductive patterns of three widespread scleractinian corals of this region—Pocillopora damicornis (branching colony morphology, characterized as hermaphrodite broadcaster), Pavona gigantea (massive colonies, characterized as gonochoric broadcaster/sequential co‐sexually hermaphroditic) and Porites panamensis (encrusting colonies, characterized as gonochoric brooder)—were evaluated at local and regional scales across the ETP. This area extended from the Gulf of California (24°N) to the southern coast of Ecuador (–1°S), including offshore islands, using existing data pooled from prior studies. Predictive models were employed based on environmental variables: sea surface temperature, daylight hours, diffuse attenuation co‐efficient at 490 nm and photosynthetically active radiation. Datasets were extracted from satellite images (https://oceancolor.gsfc.nasa.gov) and analysed using WAM_STATIST ver. 6.33® software to obtain monthly average data from each site. The spatial (region, sub‐region and site) and seasonal (wet, dry) variation in reproductive activity (% colonies with gametes) differed among the three species; significant interactions were season × sub‐region for P. damicornis, season × site (sub‐region) for P. gigantea, and season × site for P. panamensis, for which sub‐region was not considered as a factor. The predictive models also suggest that gamete production/maturation of P. damicornis and P. gigantea is influenced by local differences in sea surface temperature and daylight hours. Porites panamensis was not correlated with any environmental variable examined. Variations in local and regional reproductive developmental patterns are likely an acclimatization response by each species imposed by the timing and duration of local stressor events. This analysis has provided insights into the diverse local and regional physical drivers that affect species responses and acclimatization in sexual reproduction across the ETP.

Evidence of Sexual Reproduction in Out-Planted Coral Colonies

“…To avoid bias, all colonies had a diameter of 40-50 cm, which is a marker that the coral colony has reached its reproductive age [23]. Since the study seeks to demonstrate the presence/maturation of gametes, colonies were sampled monthly from June to October, when reproductive activity has been previously recorded in the region [24,25]. From each coral colony, a 1 cm fragment was removed each month using a chisel and a hammer and fixed in 10% seawater formaldehyde until histological analyses were made.…”

Internal ultrastructure of the planktonic larva of the coral Porites panamensis (Anthozoa: Scleractinia)

“…The mode and reproduction patterns of scleractinian corals are both species-specific and spatiotemporally variable (Chávez-Romo et al, 2013;Santiago-Valentín et al, 2018). At the regional level, the Eastern Tropical Pacific (ETP) environmental conditions are considered limiting for the development of coral communities (Dana, 1975;Glynn et al, 1996;Richmond, 1990).…”

“…At the regional level, the Eastern Tropical Pacific (ETP) environmental conditions are considered limiting for the development of coral communities (Dana, 1975;Glynn et al, 1996;Richmond, 1990). Conditions such as the wide ranges of annual temperature fluctuations (18 to 32 °C), low pH (7.72 to 8.03) (Cupul-Cortés et al, 2018), high sedimentation rates (Glynn et al, 2017), seasonal upwellings (Portela et al, 2016) and internal waves that results in abnormal daily sea temperature fluctuations (Plata & Filonov, 2007), promotes non-optimal conditions that affect physiological processes with high energy demand, such as reproduction (Glynn, 2000;Glynn & D' Croz, 1990;Santiago-Valentín et al, 2018;Spalding et al, 2001). However, gamete development has recently been documented in all reef-building scleractinian corals examined in the region (Carpizo-Ituarte et al, 2011;Chávez-Romo & Reyes-Bonilla, 2007;Glynn et al, 1991;Glynn et al, 1994;Glynn et al, 1996;Glynn et al, 2017;López-Pérez et al, 2007;Medina-Rosas et al, 2005;Rodríguez-Troncoso et al, 2011;Santiago-Valentín et al, 2015), and even the developmental stages and morphology of the larvae within adult colonies have been described (Glynn et al, 2017;Santiago-Valentín et al, 2019).…”