Simon J Brandl

Marine biodiversity & ecosystem functioning

“I saw with regret, that whilst the number of accurate instruments was daily increasing, we were still ignorant”

Alexander von Humboldt



The diversity of life represents the single most unique and valuable asset of our planet. Yet, our understanding of biodiversity in the world's oceans is still rudimentary. Through my work as a marine biologist, I seek to uncover biodiversity patterns in the ocean and their effect on the functioning of marine ecosystems.

About me

I am currently a Banting postdoctoral research fellow, working in the Marine Ecology Lab at the Earth2Ocean group at Simon Fraser University. From 2015 to 2017, I was a postdoctoral fellow for MarineGEO, located at the Smithsonian Environmental Research Center in Edgewater, Maryland. I obtained my PhD from James Cook University in Australia in 2016.



My research is centered around the biodiversity and functioning of marine ecosystems. I mostly work on coral reefs and their fish communities, especially tiny, cryptobenthic fishes.



Of the millions of life forms present in the world's oceans, more than 15,000 are fishes. An additional ~5,000 species of marine fishes have yet to be described. My research seeks to shed light on the ecology, evolution, behavior, and life-history of fishes, with a particular focus on the "cryptodiversity" of cryptobenthic coral reef fishes like gobies, blennies, or triplefins. 



All ecosystems are dependent on a complex mosaic of interrelated ecological processes. I am interested in disentangling and studying the core ecological processes that govern coral reef ecosystems, with a particular emphasis on the role of biodiversity for processes such as herbivory, predation, or secondary production. 


We are witnessing an era of unprecedented human impact on ecosystems across the globe. Through my research, I hope to gain information on the effect of disturbances on ecological communities, their capacity to buffer disturbances, and the potential actions we can take to bolster ecosystems against future environmental change. 



Please find my latest publications below. Follow this link to a list of all of my publications, or access my Google Scholar or ResearchGate page using the buttons below. For information on my reviewing activities, go to my Publons profile.

A bipartite network showing trophic interactions between 22 reef fish species and their prey.

A bipartite network showing trophic interactions between 22 reef fish species and their prey.

A mixed school of Caribbean surgeonfishes, key algal consumers on coral reefs.

A mixed school of Caribbean surgeonfishes, key algal consumers on coral reefs.

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Coral reef ecosystem function: eight core processes and the role of biodiversity

Frontiers in Ecology and the Environment (in press)

In times of rapid environmental change, calls to manage coral reefs for functionality have strengthened. But what defines a functional coral reef? In our new paper, we partition coral reef ecosystem functioning into eight core processes that form the pulse of reefs. Under this framework, we can start exploring the role of species communities on functioning. Are critical processes on reefs driven by few key species or the collective effects of their staggering biodiversity? Understanding these dynamics will impart indispensable knowledge on our management efforts of reefs in the present and the future.

Demographic dynamics of the smallest marine vertebrates fuel coral-reef ecosystem function

Science 364: 1189-1193

How coral reefs survive as oases of life in marine deserts has puzzled scientists for centuries. In our new paper, we show that the world’s smallest marine vertebrates may have a role to play in this. Tiny, ‘cryptobenthic’ fishes provide the majority of consumed fish biomass on coral reefs. They do so by having broken with fundamental paradigms: first, despite their vertebrate origins, these fishes live fast and die young, much like many terrestrial invertebrates. Second, to maintain this lifestyle, cryptobenthic fishes have essentially abandoned long-range dispersal across the open ocean and instead keep their larvae close by to immediately replenish each eaten adult.

Reconstructing hyperdiverse food webs: gut content metabarcoding as a tool to disentangle trophic interactions on coral reefs

Methods in Ecology and Evolution (in press)

There are more than 800,000 species predicted to occur on coral reefs worldwide. As a consequence, the number of potential predator-prey linkages is virtually inexhaustible. Using gut-content DNA metabarcoding, we have decomposed a coral reef food web consisting of 22 predominantly invertebrate-feeding fishes and their prey. The results in the paper led by postdoc Jordan Casey show that there is substantial dietary partitioning even among closely related species that are generally considered functionally equivalent. When we formally tested for the explanatory power of these coarse, preconceived functional groups, the results were… well, underwhelming. The paper emphasizes the need for high-resolution assessments of species’ resource use if we are to understand energy fluxes on reefs.


Marine protected areas enhance coral reef functioning by promoting fish biodiversity

Conservation Letters (in press)

Herbivory is considered a key functional process on coral reefs. But what drives rates of herbivory on a global scale? My former student and field assistant Zachary Topor examined this question using a meta-analysis of macroalgal browsing rates on coral reefs. We found that, the strongest driver of herbivory rates on coral reefs is the local biodiversity of herbivores and that, encouragingly, herbivore diversity can be enhanced via the implementation of marine protected areas. At least for one aspect of coral reef functioning, managing for diversity appears to promote functionality! Check out the open-access paper here.


The hidden half: ecology and evolution of cryptobenthic fishes on coral reefs

Biological Reviews 93: 1846-1873

In this paper, we provide the first quantitative definition to delineate a core group of cryptobenthic fish families, showing that size-distributions within families produce a remarkable separation between 17 cryptobenthic and 41 large reef fish families. We further model the rates at which reef fish species have been (and will be) described from the mid-1700s until the year 2050, predicting that by the year 2032, 17 families of cryptobenthic fishes will account for more than half of the described fish diversity on coral reefs. We highlight some of the processes that may have given rise to the extreme species richness of cryptobenthic reef fishes. In addition, we emphasize the paucity of quantitative data on crypto-assemblages worldwide, both geographically and across depths. Finally, we summarize some of the most salient limitations that small body size imposes on the ecology of cryptobenthic reef fishes and detail adaptations that permit these organisms to flourish and occupy a unique functional role on reefs. It's all you ever wanted to know about the smallest marine vertebrates (or at least a good start -- lots more to be discovered).


Bottom-up processes mediated by social systems drive demographic traits of coral reef fishes

Ecology 99, 642-651 

Using data on parrotfish populations across the Great Barrier Reef, we show that the exposure regime reefs are subject to is the single best predictor of life-history traits. Surprisingly, we found a lack of empirical support for any of the variables that are commonly assumed to drive life-history traits in these fishes, such as intraspecific competition or predation. We analyzed data on the length at sex-change in a structural equation model, demonstrating that both overall population size and the length at which parrotfish ladies turn into parrotfish men are most strongly affected by shelf position. We hypothesize that this is primarily driven by bottom-up processes that are affected by different disturbance regimes at mid-shelf vs. outer-shelf sites. Overall, the paper provides an excellent case for integrating life-history traits with social systems and ecological processes in order to understand how ecosystems function. Oh, and there are some fun blogposts about the paper...


Marine dock pilings foster diverse, native cryptobenthic fish assemblages across bioregions

Ecology & Evolution 3:3288

In this paper, my co-authors and I show that marine dock pilings, a habitat that is becoming ever more prevalent on the world's shorelines, can foster diverse assemblages of native, regionally characteristic cryptobenthic fishes. These assemblages appear to follow traditional ecological paradigms, like the Latitudinal Diversity Gradient, as their species richness declined sharply from Panama to Maine. We suggest that, in contrast to findings from sessile epifauna, dock pilings can provide a valuable habitat for the conservation and monitoring of vertebrate biodiversity in heavily anthreopogenically impacted environments. 


Quick Guide: Cryptobenthic Reef Fishes

Current Biology 27, R452-454

In this short opinion piece, Chris Goatley and I provide a short introduction to the life (and death) of cryptobenthic reef fishes. What are cryptobenthic fishes? What do they do? Where do they occur? And why should we care? Check out the paper to find the answers to these questions and take a moment to appreciate the extraordinary diversity of the shapes and colors of cryptobenthic reef fishes.

A squidpop, investigated by a curious striper ( M. saxatilis ).

A squidpop, investigated by a curious striper (M. saxatilis).

Consumption pressure in coastal marine environments decreases with latitude and in artificial vs. natural habitats

Marine Ecology Progress Series, in press

In this paper, my student Jon Rodemann and I used a standardized predation assay to test whether consumption pressure increases towards the tropics. Using "squid-pops" (i.e. a piece of dried squid tied to a garden stake) deployed underneath and a short distance away from marine dock pilings, we show that consumption pressure decreases sharply from Florida to Maine. Stay tuned for the full paper to be published in MEPS!

Functional changes in the reef fish communities around Lizard Island afetr Cyclone Ita.

Functional changes in the reef fish communities around Lizard Island afetr Cyclone Ita.

Habitat degradation increases functional originality in highly diverse coral reef fish assemblages

Ecosphere 7, e01557

What happens to the functional composition of reef fish assemblages after a major disturbance that decreases coral cover? We answer this question by determining the functional community structure of reef fishes on Lizard Island before and after Cyclone Ita pummeled the island in 2015. Using functional diversity indices and Bayesian models, we demonstrate that reef fishes become more functionally unique after the disturbance, suggesting that species with common, widely shared functional attributes are being lost. In particular, the many small, planktivorous fishes that require coral for shelter appear to be the most affected species.