Coral Spawning

Image: Edgar Escalante Mancera

Caribbean Coral Spawning Database


To continue to support our Caribbean-wide colleagues with coral response and rescue efforts following SCTLD, we are hosting this collaborative webpage on coral spawning in the Caribbean which includes a Coral Spawning Survey form and Tracking Map (similar to the SCTLD and Diadema tracking maps), Spawning Calendars available for different areas, and links to resources. We are collaborating with Anastazia Banaszak of Coralium/UNAM to help oversee data which will be used to further develop spawning calendars for different coral species and regions. Knowing which corals are sexually mature and spawning and in what locations will help advance rescue efforts.

Join us in tracking coral spawning across the Caribbean. Together, scientists, divers, and underwater photographers can share what they see. Every record of date, time, and coral species spawning is helping scientists better understand and predict future spawning events and guide restoration efforts such as larval propagation. If you have additional links or resources you would like to share, please contact us at


Coral reproduction

Corals have two distinct forms of reproduction: asexual and sexual reproduction.

Asexual reproduction: Asexual reproduction can occur either by budding or by fragmentation. Budding is when a coral polyp divides forming two identical polyps. This is how a colony grows from starting as one (primary) polyp to form a colony of numerous interconnected polyps. Fragmentation occurs when a piece or pieces of the colony break off and if any of these pieces survive can form new, but genetically exact copies of the mother colony.

Sexual reproduction: Corals can also form new colonies by sexual reproduction. Within each coral polyp there are reproductive cells called gametes, which are eggs and/or sperm. Some species of corals produce both eggs and sperm and are called hermaphrodites, whereas other species have separate sexes, whereby each colony produces either eggs or sperm.

Coral Spawning: Coral colonies of the same species release their gametes simultaneously into the water column at specific times and on specific nights, generally in the summer months, in an event called coral spawning. Hermaphroditic species release their gametes as bundles of eggs and sperm. Coral eggs have a high lipid content therefore the bundles are slightly positively buoyant and float upward to the surface of the ocean. Here the motion of the waves causes the bundles to break up and release the sperm and eggs to mix with the sperm and eggs from other colonies of the same species. This increases the chances of successful fertilization as it maximizes the encounter between eggs and sperm from different colonies. Biologists who study coral reproduction can use such events to capture gametes and take them back to their labs to culture the eggs and sperm and form new corals.

Sexual reproduction helps to maintain genetic diversity by the exchange of genetic material between different colonies of the same species, thus ensuring resilience and adaptation to changing environmental conditions.

To help predict when different species of corals spawn, we have set up a database for tracking spawning, where anyone can report their spawning observations. It is just as useful to report when spawning occurred as when spawning did not occur. This way we can map and help to predict with more certainty when corals will spawn. These data will help scientists who are working to better understand coral reproduction, as well as those who are culturing corals to help restore degraded coral reefs. The data are also useful for scientists who are cryopreserving gametes to help coral conservation and restoration efforts.

Factors such as pollution, climate change, and coastal developments pose significant threats to coral reefs and can disrupt their reproductive cycles, potentially jeopardizing their long-term survival. Coral spawning is a critical event for the survival and growth of coral populations, which is why it is so important to track when it occurs.


Coral Rescue

Many species that are susceptible to stony coral tissue loss disease (SCTLD) release their gametes in mass spawning events. Broadcast spawning allows cross-fertilization of coral gametes, producing genetic variation in their offspring and increasing the chances for adaptive resilience of populations during conditions of environmental change. ​In locations that have been devastated by SCTLD, the number and density of disease-susceptible corals (remnant survivors and apparently resilient genotypes) in some species is now so low that effective cross-fertilization is unlikely to occur during spawning events. The chances of survival for these imperiled populations are enhanced by the collection and assisted fertilization of their gametes, followed by propagation of the resulting larvae. The purpose of coral rescue is to save some of the region’s unique biodiversity for future reef restoration efforts whenever more benign environmental conditions might allow.

Preparing for Spawning Season

How to Submit Your Data

Help us track coral spawning in the Caribbean. Enter your observations, locations, and photos (if available) by clicking on the Submit button below. Reports are shown on the tracking map. Survey forms are available in other languages (click on the Language button in in the upper right within the form).

For more information, contact us at

Tracking Coral Spawning in the Caribbean

This new map has just been developed. As new data is entered, it will appear on the map. Stay tuned for more!

NEW Coral Breeding Reference Sheets

The Coral Reef Consortium (CRC) recently released NEW Coral Breeding Reference Sheets (CBRS) developed by the CRC Larval Propagation Working Group in partnership with SECORE International. The 4 CBRS include Acropora palmata, Orbicella faveolata, Diploria labyrinthiformis, and Porites porites.  To access them, click on the photo below. For more resources see the CRC’s Propagation and outplanting resources.

New Coral Spawning Predictions

The following slides for individual coral species are from the July 10, 2023 webinar for CCT given by Anastazia T. Banaszak (Coralium – UNAM).

What Does Coral Spawning Look Like?

Video: Click on the image to the right to view video or click link here:  PSTR spawning in 2020 in Bocana.

Video by Raul Tecalo Renteria.


Spawning Calendars

Mexican Caribbean – information provided by Coralium Lab.  For more information, contact Anastazia T. Banaszak, Coralium, UNAM,

Coral Spawning Prediction Calendar 2023 Mexican Caribbean

Southern Caribbean – information provided by CARMABI

2023 Coral Spawning Predictions for the Southern Caribbean

Coral Spawning Data Sheet

Coral Spawning Data Sheet. If you have questions, contact Anastazia T. Banaszak, Coralium, UNAM,

Coral Spawning Data Template 2023


Coralium Lab :

SECORE International:

Dominican Republic : FUNDEMAR 

Southern Caribbean : CARMABI

The Bahamas Perry Institute for Marine Science: Perry Institute for Marine Science: The Bahamas.

Flower Garden Banks National Marine Sanctuary Coral Spawning (

​Coral Spawning Research Group (CSRG)


For more information about Caribbean spawning please contact Anastazia T. Banaszak , email:

Related Publications

Leinbach, S.E., Speare, K.E., Rossin, A.M. et al. Energetic and reproductive costs of coral recovery in divergent bleaching responses. Sci Rep 11, 23546 (2021).

Levitan, D. R., Boudreau, W., Jara, J., and Knowlton, N. (2014). Long-term reduced spawning in Orbicella coral species due to temperature stress. Mar. Ecol. Prog. Ser. 515, 1–10.

Randall, C. J., and Szmant, A. M. (2009). Elevated temperature affects development, survivorship, and settlement of the elkhorn coral, Acropora palmata (Lamarck 1816). Biol. Bull. 217, 269–282.

Cox, E. F. (2007). Continuation of sexual reproduction in Montipora capitata following bleaching. Coral Reefs 26, 721–724.

Szmant, A.M., Gassman, N.J. The effects of prolonged “bleaching” on the tissue biomass and reproduction of the reef coral Montastrea annularis . Coral Reefs 8, 217–224 (1990).


The Caribbean Coral Spawning Database is a collaboration of organizations and individuals working together to track coral spawning and help advance coral rescue and recovery.

We welcome you to join our efforts to share information and resource links.  Contact us at