Turtles, corals, and beautiful bold clownfish are the poster children on coral reefs; they are marvellous creatures that every diver, snorkeler and funder love! However, these are not the only sea creatures that require our attention. Hidden throughout coral reefs are tiny fishes that have vital roles (Brandl et al., 2019). Yet, because of their small size and the fact that you can barely see them, the importance of these fishes is often undervalued (Bellwood et al., 2020).
My PhD research focuses on small, cryptic coral reef fishes of the genus Trimma (pictured). Like many small and cryptic species, this genus has been forgotten in most existing literature. As a result, we know little about their basic ecology and life history (Winterbottom, 2019). Trimma include some of the smallest fishes on the reef, growing to a maximum of just 3cm! Throughout my research journey, I have uncovered some exciting details about their secret lives…
Firstly, their small size suggests they do not contribute much energy to coral reef ecosystems compared to larger fishes. However, they are highly abundant, grow quickly, die young, and have efficient reproductive techniques to procreate before their short life ends. These characteristics indicate that new generations can be produced successfully and rapidly, so their energy contributions to coral reefs may be markedly high over time. Shortly, I will be looking at what they eat to uncover their roles on coral reefs further. For example, it has been suggested that Trimma may be importing energy onto the reef by ingesting plankton or they may be recycling nutrients by consuming food items on the bottom of the reef (Winterbottom, 2019).
Any animal that can catch small cryptic fishes like Trimma can eat them due to their small size (Goatley et al., 2017). Novel research shows they provide almost 60% of fish flesh consumed on coral reefs (Brandl et al., 2019). Meaning these small fishes are fuelling larger animals on the reef! So even though they may seem tiny and insignificant, it is crucial not to overlook these forgotten fishes, because they are more important than you think!
Bellwood, D. R., Hemingson, C. R., & Tebbett, S. B. (2020). Subconscious Biases in Coral Reef Fish Studies.
Bioscience, 70(7), 621-627. https://doi.org/10.1093/biosci/biaa062
Brandl, S. J., Tornabene, L., Goatley, C. H. R., Casey, J. M., Morais, R. A., Côté, I. M., Baldwin, C. C., Parravicini, V., Schiettekatte, N. M. D., & Bellwood, D. R. (2019). Demographic dynamics of the smallest marine vertebrates fuel coral reef ecosystem functioning. Science (American Association for the Advancement of Science), 364(6446), 1189-1192. https://doi.org/10.1126/science.aav3384
Goatley, C. H. R., González-Cabello, A., & Bellwood, D. R. (2017). Small cryptopredators contribute to high predation rates on coral reefs. Coral Reefs, 36(1), 207-212. https://doi.org/10.1007/s00338-016-1521- 1
Winterbottom, R. (2019). An illustrated key to the described valid species of Trimma (Teleostei: Gobiidae). journal of the Ocean Science Foundation, 34, 1–61. https://doi.org/https://doi.org/10.5281/zenodo.3525430