# Rank change and growth within social hierarchies of the orange clownfish, Amphiprion percula

L M Fitzgerald, H B Harrison, D J Coker, P Sáenz-Agudelo, M Srinivasan, J E Majoris, L Boström Einarsson, B Pujol, M Bennett-Smith, S R Thorrold, et al.

► To cite this version:

L M Fitzgerald, H B Harrison, D J Coker, P Sáenz-Agudelo, M Srinivasan, et al. Rank change and growth within social hierarchies of the orange clownfish, Amphiprion percula. Marine Biology, 2022, 169 (10), pp.128. 10.1007/s00227-022-04117-9. hal-04018289

HAL Id: hal-04018289

https://hal.science/hal-04018289

Submitted on 7 Mar 2023

HAL is a multi-disciplinary open access
archive for the deposit and dissemination of sci-
entific research documents, whether they are pub-
lished or not. The documents may come from
teaching and research institutions in France or
abroad, or from public or private research centers.

L'archive ouverte pluridisciplinaire HAL, est
destinée au dépôt et à la diffusion de documents
scientifiques de niveau recherche, publiés ou non,
émanant des établissements d'enseignement et de
recherche français ou étrangers, des laboratoires
publics ou privés.

<figure><img src="image_1.png" /></figure>

Distributed under a Creative Commons Attribution 4.0 International License
# Rank change and growth within social hierarchies of the orange clownfish, *Amphiprion percula*

L. M. Fitzgerald<fnref n="1" />,<fnref n="2" /> ID • H. B. Harrison<fnref n="3" />,<fnref n="4" /> ID • D. J. Coker<fnref n="1" /> ID • P. Sáenz-Agudelo<fnref n="5" /> ID • M. Srinivasan<fnref n="3" />,<fnref n="6" /> ID • J. E. Majoris<fnref n="1" /> ID

L. Boström Einarsson<fnref n="3" />,<fnref n="6" /> ID • B. Pujol<fnref n="7" /> ID • M. Bennett-Smith<fnref n="1" /> ID • S. R. Thorrold<fnref n="8" /> ID • S. Planes<fnref n="7" /> ID • G. P. Jones<fnref n="3" />,<fnref n="6" /> ID

M. L. Berumen<fnref n="1" /> ID

Received: 11 August 2021 / Accepted: 26 September 2022 / Published online: 5 October 2022

© The Author(s) 2022

## Abstract

Social hierarchies within groups define the distribution of resources and provide benefits that support the collective group or favor dominant members. The progression of individuals through social hierarchies is a valuable characteristic for quantifying population dynamics. On coral reefs, some clownfish maintain size-based hierarchical communities where individuals queue through social ranks. The cost of waiting in a lower-ranked position is outweighed by the reduced risk of eviction and mortality. The orange clownfish, *Amphiprion percula*, maintains stable social groups with subordinate individuals queuing to be part of the dominant breeding pair. Strong association with their host anemone, complex social interactions, and relatively low predation rates make them ideal model organisms to assess changes in group dynamics through time in their natural environment. Here, we investigate the rank changes and isometric growth rates of *A. percula* from 247 naturally occurring social groups in Kimbe Island, Papua New Guinea (5° 12' 13.54" S, 150° 22' 32.69" E). We used DNA profiling to assign and track individuals over eight years between 2011 and 2019. Over half of the individuals survived alongside two or three members of their original social group, with twelve breeding pairs persisting over the study period. Half of the surviving individuals increased in rank and experienced double the growth rate of those that maintained their rank. Examining rank change in a wild fish population provides new insights into the complex social hierarchies of reef fishes and their role in social evolution.

**Keywords** Vertebrate growth • Reef fish • Clownfish • Social hierarchy

## Introduction

Social hierarchies help group-living animals distribute resources, including food, shelter, and mating privileges (Koski et al. 2015). Individuals are ranked by their position

Responsible Editor: D. Goulet.

<figure><img src="image_2.png" /></figure>

L. M. Fitzgerald
lucy.fitzgerald@unil.ch

<footnote n="1">¹ Red Sea Research Center, Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology, Thuwal, Makkah Province 23955-6900, Saudi Arabia</footnote>

<footnote n="2">² Present Address: Department of Computational Biology, University of Lausanne, Lausanne, Switzerland</footnote>

<footnote n="3">³ ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, QLD 4811, Australia</footnote>

<footnote n="4">⁴ Australian Institute of Marine Science, Townsville, QLD 4811, Australia</footnote>

<footnote n="5">⁵ Instituto de Ciencias Ambientales y Evolutivas, Universidad Austral de Chile, Valdivia, Chile</footnote>

<footnote n="6">⁶ College of Science and Engineering, James Cook University, Townsville, QLD 4811, Australia</footnote>

<footnote n="7">⁷ Laboratoire d'Excellence CORAIL EPHE, PSL Research University, UPVD, CNRS, USR, 3278 CRIOBE, BP 1013, 98729 Papetoai, Moorea, French Polynesia</footnote>

<footnote n="8">⁸ Biology Department, Woods Hole Oceanographic Institution, Woods Hole, Falmouth, MA 02543, USA</footnote>
in the hierarchy, which is driven by physical and competitive fitness (e.g., size, strength, coloration), and how they contribute to the functioning of the social group (Koski et al. 2015). Hierarchies are typically structured according to the individuals' size, age, or sex, and moving up in social rank increases an individual's access to food (Forrester 1991), mates (Buston 2003a), and habitat (Thompson et al. 2007). Social rank often corresponds to feeding success rates, which are correlated to growth rates, and allows dominant individuals to remain well-fed where food is limited (Gurney and Nisbet 1979). Reef fish are a popular vertebrate model to study hierarchy and dominance since they have a clear social structure and can be kept easily in laboratory settings; for example, the coral-dwelling goby *Paragobiodon xanthosomus* exhibits a size-based hierarchy in which members form a queue to inherit breeding status from the dominant pair. Cooperation between subordinates regulates growth and maintains a size ratio between ranks to avoid conflict, punishment, or eviction from the social group (Wong et al. 2007). While studies have examined the causes of rank change and dominance in reef fish by analyzing growth rates (Wong et al. 2007, 2016; Reed et al. 2019), they are conducted as short-term experiments (Buston 2003a, 2003b; Buston and Cant 2006; Rueger et al. 2018). No studies have examined rank change and growth rates in fish over one year in a natural setting. Long-term studies aid in the understanding of population dynamics by providing large datasets that are used to predict future population changes, but large datasets can be challenging to obtain in the marine environment (Reinke et al. 2019).

Mating behavior is essential in driving, establishing, enforcing, and maintaining the social hierarchy. Sexual selection within hierarchical societies elucidates patterns of conflict within as opposed to between sexes. Wong and colleagues determined that food limitation and paternal egg care lead to competition among female coral gobies for males meaning they are less likely to mate with subordinate males, leading to monogamy within social groups (Wong et al. 2008). Most clownfish live in groups comprising one dominant breeding pair and several non-breeding subordinates where the female is the dominant individual. The species *Amphiprion bicinctus* and *Amphiprion akallopisos* have been shown to exhibit monogamy based on the individual recognition (Fricke 1973) and pair-bonding (Fricke 1974). Fricke and Fricke also found that several pairs of *A. bicinctus* remained on the same anemone without changing partners for at least three years (Fricke and Fricke 1977), revealing that social structures are relatively stable for females and males.

In this study, we focus on the orange clownfish, *Amphiprion percula* examining its rank change and growth over an eight-year time gap. The orange clownfish, *A. percula* (Lacepède, 1802), is one of 28 species of clownfish

belonging to the subfamily Amphiprioninae within the family Pomacentridae. It is estimated to have a lifespan of 30 years (Buston and Garcia 2007) and is commonly associated with anemone hosts *Heteractis magnifica* and *Stichodactyla gigantea* (Fautin and Allen 1992). Anemone species may play an essential role in the growth and size of *A. percula* individuals. Previous studies found that, on average, females were 10% larger in *H. magnifica* compared to those living on *S. gigantea*, and individuals that settled on *H. magnifica* had a faster growth rate based on otolith increments (Salles et al. 2016). A recent study (Salis et al. 2021) concluded that juvenile *A. percula* delays the development of their white bars during metamorphosis depending on the anemone species they are hosted by, emphasizing the importance of anemone host species on a variety of biological factors. Additionally, anemone surface area significantly impacts the social structure, with larger anemones hosting larger social groups and individuals (Chausson et al. 2018), which may place additional pressure on resource sharing and individual growth.

Within social groups of *A. percula*, there is a strict size-based ratio between sequentially ranked individuals in which a dominant individual is approximately 1.26 times the size of its immediate subordinate (Buston 2003b). Similar to gobies, subordinates regulate their growth to maintain this ratio or are otherwise evicted or killed (Buston 2003b; Rueger et al. 2018). In theory, individuals who change rank grow faster due to the increase in the food they consume as they rise in status. This study aimed to examine rank changes and growth in naturally occurring social groups of *A. percula* clownfish over eight years on shallow coral reefs on Kimbe Island, Papua New Guinea. We hypothesize that individuals who change rank will grow faster than those who do not change rank, and those with higher rank will have better survivorship. During this time, individuals were exposed to natural levels of predation risk, food availability, and recruitment.

# Materials and methods

## Sample collection

The *Amphiprion percula* population on Kimbe Island (5° 12' 13.54" S, 150° 22' 32.69" E), a remote island in Kimbe Bay, was sampled in March 2011 and April 2019. Each time, all individuals sized > 25 mm (n=660 in 2011; n=533 in 2019) were caught with hand nets, occasionally anesthetized with a dilute solution of clove oil (if necessary to facilitate capture), and measured to the nearest mm (total length, TL) (Fig. S1). Their host anemone species (*S. gigantea* and *H. magnifica*) were recorded and tagged with a cattle tag and buoy (Fig. 1). Due to the attrition

<figure><img src="image_3.png" /></figure>
<figure><img src="image_4.png" /><figcaption>**Fig. 1** A Visual of the study site, Kimbe Island (Papua New Guinea), and surround-ing lagoon and reef habitats with tagged anemone locations (*Heteractis magnifica* in red and *Stichodactyla gigantea* in yellow). Kimbe Island = green, shallow (< 1 m) hard bottom substrate = gray, lagoons = light blue, and deeper ocean outside of the fringing reef habi-tat = dark blue. Host anemones *Heteractis magnifica* (B) and *Stichodactyla gigantea* (C) on the right. Aerial image credit to H.B.H., map courtesy U. Langner (RSRC), photographs credit to M.B.S</figcaption></figure>

of the tags on anemones, we could not confirm that all
individual fish had remained on the exact anemone host
between sampling times. For some fish, we can only con-
firm that they were found on the same species of anemone
and general area based on GPS. To genotype all individu-
als, a tissue sample was taken from the caudal fin before
they were released back onto their anemone host. The fin
clip is regrown within approximately two weeks and has
no adverse long-term effects on the fish. Samples were
preserved in 96% ethanol. Rank was assigned based on
the relative total lengths of individuals within each social
group. Rank 1 was the largest individual and assumed to
be the female; rank 2 was the second largest and assumed
to be the male. Any additional individuals were classed
as sub-adults.

Sample processing and genotyping

Genomic DNA from *A. percula* fin clips ~ 2 mm² was extracted using the Macherey–Nagel 96 tissue kits following the manufacturer’s protocols. Next, microsatellite loci were amplified using the QIAGEN Multiplex PCR kit following the protocol in Almany et al. (2017). Forward primers were labeled with fluorescent tags and pooled into four multiplex mixes indicated in Table S1. PCR products were analyzed on an ABI 3730×1 genetic analyzer (Applied Biosystems). Allele sizes for 20 microsatellite loci were successfully amplified and were manually scored in the fragment analysis software *GENEMAPPER* v4.0. Characteristics of the 20 microsatellite markers were

analyzed in *GenAIEx* v6.5 (Peakall and Smouse 2012) and
are presented in Table S2. Alleles were binned in R (R
Core Team 2020) using the package *MsatAllele* (Alberto
2009).

Individuals that survived from 2011 to 2019 were iden-
tified in the R package *AlleleMatch* (Galpern et al. 2012).
Only individuals classed as females, males, or sub-adults
were included in this analysis (n=660 in 2011 and n=533
in 2019). A sensitivity analysis indicated that up to 8 gen-
otypic mismatches could confidently identify identical
genotypes within the sample.

Statistical analyses

We measured growth between 2011 and 2019 as the per-
cent increase in body length between the two measurements.
Variation in growth between anemone species, rank status,
or change was assessed using generalized linear mixed
models with a beta error distribution with a logit link in
the R package *glmmTMB* (Friedman et al. 2010). The inter-
actions between anemone species and rank were explored
and found not to be important. Estimated marginal means
and Tukey post hoc pairwise comparisons with 95% confi-
dence intervals were calculated using the package *emmeans*
(Lenth 2021) and plotted using the package *ggplot2* (Wick-
ham 2016). Model residuals were inspected in the *DHARMa*
package (Hartig 2020) and checked for homogeneity of vari-
ance, dispersion, and outliers. Model selection was informed
by AIC scores using the *MuMln* package (Barton 2020). All
analyses were performed in R version 4.0.2 (R Core Team
2020).
## Results

In total, 134 of the 660 individuals (i.e., 20%) sampled in 2011 were recaptured in 2019, including 36 females, 52 males, and 46 sub-adults, and comprised 35 of the original 247 social groups from 2011. Of the 134 survivors, 72 individuals were confirmed to have been collected from the same anemone with other individuals from the same social group. We found no evidence of an individual changing anemone host over the eight years; the other 62 individuals were identified in anemones without a matching anemone ID tag between 2011 and 2019 but on the same species of anemone, at similar depths, in the same general location. We found that 60% of the 134 survivors were from anemone *H. magnifica*, and 40% were from *S. gigantea*.

Of the 134 survivors, 67 individuals (50%) maintained the same rank within their respective social groups, and 67 individuals (50%) changed social rank to become male or female (Fig. 2). Additionally, we identified 12 mating pairs that remained together since 2011, of which three remained with other individuals from their original social group. The host anemone, initial rank, and rank change

strongly affected individuals' growth between 2011 and 2019. Changes in rank had the strongest effect on growth resulting in a 26.8% (95% CI [24.5–29.1]) increase in growth for individuals that changed rank compared to 11.7% (95% CI [10.0–13.6]) in individuals that did not change rank, and the difference was significant between the two groups ($p < 0.0001$). The strongest effects were observed in sub-adults that became either male (27.0% growth, 95% CI [23.2–31.2]) or females (31.4% growth, 95% CI [26.4–36.9]) during the eight-year window (Table 1). Males that became females grew by 24.7% (95% CI [21.8–27.8]). Of the individuals that did not change rank, sub-adults grew fastest with 18.9% growth (95% CI [14.4–24.4]), faster than either females (10.8% growth, 95% CI [8.9–13.1]; $p = 0.015$) or males (10.0% growth, 95% CI [7.6–13.0]; $p = 0.012$). Anemone species also had

<figure><img src="image_5.png" /><figcaption>**Fig. 2** Rank and rank changes in 134 *Amphiprion percula* individuals collected in 2011 and recaptured in 2019. Their identities were confirmed by their unique DNA profiles</figcaption></figure>

<figure><img src="image_6.png" /><figcaption>**Fig. 3** Growth of *Amphiprion percula* as a percentage of the total body length for females, males, and sub-adults depending on whether individuals changed social rank within different host anemones. Estimated marginal means are shown with 95% confidence intervals around the mean</figcaption></figure>

<table><caption>**Table 1** Estimated marginal means and 95% confidence interval of the percent growth in *Amphiprion percula* between 2011 and 2019 for different social ranks and rank changes in *Heteractis magnifica* and *Stichodactyla gigantea*</caption><thead><tr><th>Anemone sp</th><th>Rank</th><th>Percent growth</th><th>n</th><th>SE</th><th>df</th><th>95% conf. int</th></tr></thead><tbody><tr><td><i>H. magnifica</i></td><td>Male (M)</td><td>8.0</td><td>12</td><td>1.1</td><td>115</td><td>[6.0–10.5]</td></tr><tr><td><i>H. magnifica</i></td><td>Female (F)</td><td>8.7</td><td>21</td><td>1.0</td><td>115</td><td>[7.0–10.8]</td></tr><tr><td><i>H. magnifica</i></td><td>Sub-adult (SA)</td><td>15.5</td><td>10</td><td>2.2</td><td>115</td><td>[11.7–20.3]</td></tr><tr><td><i>H. magnifica</i></td><td>M &gt;&gt; F</td><td>20.5</td><td>17</td><td>1.6</td><td>115</td><td>[17.5–23.8]</td></tr><tr><td><i>H. magnifica</i></td><td>SA &gt;&gt; M</td><td>22.6</td><td>15</td><td>1.9</td><td>115</td><td>[19.1–26.5]</td></tr><tr><td><i>H. magnifica</i></td><td>SA &gt;&gt; F</td><td>26.5</td><td>4</td><td>2.7</td><td>115</td><td>[21.5–32.2]</td></tr><tr><td><i>S. gigantea</i></td><td>Male (M)</td><td>12.3</td><td>7</td><td>1.7</td><td>115</td><td>[9.2–16.2]</td></tr><tr><td><i>S. gigantea</i></td><td>Female (F)</td><td>13.4</td><td>15</td><td>1.4</td><td>115</td><td>[10.9–16.3]</td></tr><tr><td><i>S. gigantea</i></td><td>Sub-adult (SA)</td><td>22.8</td><td>2</td><td>3.2</td><td>115</td><td>[17.2–29.7]</td></tr><tr><td><i>S. gigantea</i></td><td>M &gt;&gt; F</td><td>29.4</td><td>16</td><td>1.9</td><td>115</td><td>[25.8–33.2]</td></tr><tr><td><i>S. gigantea</i></td><td>SA &gt;&gt; M</td><td>31.9</td><td>7</td><td>2.6</td><td>115</td><td>[27.1–37.2]</td></tr><tr><td><i>S. gigantea</i></td><td>SA &gt;&gt; F</td><td>36.7</td><td>8</td><td>2.9</td><td>115</td><td>[31.2–42.7]</td></tr></tbody></table>
a strong effect on growth; over eight years, individuals grew 15.7% on *H. magnifica* (95% CI [14.0–17.5]) compared to 23.1% on *S. gigantea* (95% CI [20.6–25.7]), and the difference was significant (*p* < 0.0001) (Fig. 3).

## Discussion

Our study examined growth and rank change over eight years in a wild population of *A. percula* clownfish in Kimbe Island, Papua New Guinea. Tracking individuals in the marine environment over long periods can be extremely challenging. The close association of clownfish with their anemones provides a valuable model system to investigate the effects of rank change on growth, providing unique insights on survivorship, growth rates, rank changes, and the persistence of monogamous breeding pairs in coral reef fish. Our findings indicate strong survivorship of individuals over eight years, with 20% of individual resamples in 2019. Related studies of the same population but over ten years found that ~1% of the population had survived from the beginning to the end of the study (Salles et al. 2016). This suggests a complete population turnover after ten years which is short given the potential lifespan of 30 years for *A. percula* females (Buston and Garcia 2007).

Furthermore, we found that individuals that changed rank (i.e., sub-adult to male, sub-adult to female, and male to female) grew faster than those that did not change rank. Half of the surviving individuals changed rank and grew significantly more than those that did not change rank. This is likely not a standard growth, but opportunistic growth that occurs when a female or male is removed from the group since *A. percula* has been known to regulate or suppress their growth to decrease the likelihood of being evicted (Buston 2003b). A recent review by Buston and Clutton-Brock examined strategic growth in social vertebrates and concluded that clownfish species *Amphiprion perideraion* and *Amphiprion frenatus* females acquire dominant positions by increasing in length relative to similarly-sized individuals and that the increase in size is limited by the size of the anemone (Buston and Clutton-Brock 2022).

The 12 male and female pairs that persisted between 2011 and 2019 strongly support that *A. percula* is monogamous. This is consistent with previous studies of mating behavior in reef fish that are site-attached, whereby breeding pairs remain monogamous until one mate is physically removed from the social hierarchy. A review of monogamy in marine fishes included 18 families, and four clownfish species (*A. bicinctus*, *Amphiprion clarkii*, *A. perideraion*, and *A. frenatus*) identified *A. percula* as monogamous from observations only (Whiteman and Cote 2004). We can confirm from genetic analyses that 12 pairs have remained in the same

host anemone over eight years and are likely reproducing. Monogamy and breeding stability are often hard to confirm in the field over long-term studies without the adequate genetic analysis of all individuals present, making this challenging in many other field study systems.

Additionally, we found that species of anemone host significantly affected growth in *A. percula*. All individuals hosted by *H. magnifica* grew slower than those hosted by *S. gigantea*. However, previous research on early settlement in Kimbe Bay (Salles et al. 2016) found that individuals that settled on *H. magnifica* grew faster than those on *S. gigantea*. This may indicate a selective advantage on growth in *H. magnifica* for post-settlement recruits that are lost in subsequent social ranks. Since anemone surface area is positively correlated to the size of the individuals' (Chausson et al. 2018), the faster growth rates are likely explained by the larger surface area provided by *H. magnifica* compared to *S. gigantea* as observed in (Salles et al. 2016). However, this effect may also be confounded by other environmental factors associated with the different habitats occupied by each anemone. *Heteractis magnifica* are found further offshore and in deeper habitats compared to *S. gigantea* anemones found in sheltered shallow habitats close to shore (Fig. 1). Further studies that control variables, such as temperature, flow, turbidity, nutrient/food availability, predation pressure, and intraspecific competition, may provide further insight into the mechanisms that regulate growth in different anemone species. However, the scale at which these variables need to be measured to understand their impacts on the physiology and growth of clownfish would be very difficult to achieve (Burgess et al. 2021).

## Conclusion

Together, our findings support the notion that social and environmental characteristics can influence the outcome of group structure and growth (Robbins et al. 2005). This study provides the first long-term evaluation of the social structure and individual growth in a wild population of reef fish, demonstrating that growth in *A. percula* is socially mediated and strongly dependent on the host anemone. Further work should investigate the demographic consequence of faster growth and survivorship in clownfish and whether the loss of dominant and highly reproductive female fish (Saenz-Agudelo et al. 2015) can be mitigated by the rapid progression through social hierarchies and growth of lower-ranked groups.

**Supplementary Information** The online version contains supplementary material available at https://doi.org/10.1007/s00227-022-04117-9.
**Acknowledgements** We would like to thank everyone who assisted us in the field, including B. Cresswell and G. Galbraith. Additionally, we acknowledge the Mahonia Na Dari Research Station and the crew of the M. V. Febrina for providing logistical support. We thank U. Langner (KAUST), who assisted with the maps. Lastly, we also thank the anonymous reviewers for their help and feedback on this paper.

**Author contributions** LMF, HBH, and MLB: contributed to the study conception and design. Data collection was performed by LMF, HBH, PS-A, MS, JEM, LBE, BP, MBS, SRT, SP, GPJ, and MLB. Data analysis was performed by LMF, HBH, DJC, and PS-A. The first draft of the manuscript was written by LMF and all authors commented on previous versions. All authors read and approved the final manuscript.

**Funding** This research was supported by King Abdullah University of Science and Technology (baseline funds to MLB), the ARC Centre of Excellence for Coral Reef Studies (DP190103056 to GPJ), and the Australian Research Council. HBH was supported by an ARC DECRA Fellowship (DE160101141).

**Availability of data and material** All data generated or analyzed during this study are linked in this published article's supplementary information files.

## Declarations

**Conflict of interest** We declare no conflicts or competing interests.

**Ethical approval** The authors declare that the sampling of specimens was performed in the respect of the ethical rules and Papua New Guinea laws. All samplings were authorized by King Abdullah University of Science and Technology (KAUST—Field Research Plan 20190227).

**Open Access** This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.

## References

Alberto F (2009) MsatAllele_1.0: An R package to visualize the binning of microsatellite alleles. J Hered 100:394-397. https://doi.org/10.1093/jhered/esn110

Almany GR, Planes S, Thorrold SR, Berumen ML, Bode M, Saenz-Agudelo P, Bonin MC, Frisch AJ, Harrison HB, Messmer V, Nanninga GB, Priest MA, Srinivasan M, Sinclair-Taylor T, Williamson DH, Jones GP (2017) Larval fish dispersal in a coral-reef seascape. Nat Ecol Evol. https://doi.org/10.1038/s41559-017-0148

Bartoń K (2020) MuMln: multi-model inference. R package version 1.43.17. https://CRAN.R-project.org/package=MuMln

Burgess SC, Johnston EC, Wyatt AS, Leichter JJ, Edmunds PJ (2021) Response diversity in corals: hidden differences in bleaching mortality among cryptic *Pocillopora* species. Ecology. https://doi.org/10.1002/ecy.3324

Buston PM (2003a) Mortality is associated with social rank in the clown anemonefish (*Amphiprion percula*). Mar Biol 143:811–815. https://doi.org/10.1007/s00227-003-1106-8

Buston PM (2003b) Social hierarchies: size and growth modification in clownfish. Nature 424:145–146

Buston PM, Cant MA (2006) A new perspective on size hierarchies in nature: patterns, causes, and consequences. Oecologia 149:362–372. https://doi.org/10.1007/s00442-006-0442-z

Buston PM, Clutton-Brock T (2022) Strategic growth in social vertebrates. Trends Ecol Evo. https://doi.org/10.1016/j.tree.2022.03.010

Buston PM, Garcia MB (2007) An extraordinary life span estimate for the clown anemonefish *Amphiprion percula*. J Fish Biol 70:1710–1719. https://doi.org/10.1111/j.1095-8649.2007.01445.x

Chausson J, Srinivasan M, Jones GP (2018) Host anemone size as a determinant of social group size and structure in the orange clownfish (*Amphiprion percula*). PeerJ 6:e5841. https://doi.org/10.7717/peerj.5841

Fautin DG, Allen GR (1992) Field guide to anemone fishes and their host sea anemones. Western Australian Museum, Perth

Forrester GE (1991) Social rank, individual size and group composition as determinants of food consumption by humbug damselfish, *Dascyllus aruanus*. Anim Behav 42:701–711. https://doi.org/10.1016/S0003-3472(05)80116-2

Fricke HW (1973) Individual partner recognition in fish: field studies on *Amphiprion bicinctus*. Naturwissenschaften 60:204–205. https://doi.org/10.1007/BF00599441

Fricke HW (1974) Eco-ethology of the monogamous anemone fish *Amphiprion bicinctus* (field studies in the Red Sea). Z Tierpsychol 36:429–512

Fricke HW, Fricke S (1977) Monogamy and sex change by aggressive dominance in coral reef fish. Nature 266:830–832. https://doi.org/10.1038/266830a0

Friedman J, Hastie T, Tibshirani R (2010) Regularization paths for generalized linear models via coordinate descent. J Stat Softw 33:1–22

Galpern P, Manseau M, Smith K, Wilson P (2012) Allelematch: an R package for identifying unique multilocus genotypes where genotyping error and missing data may be present. Mol Ecol Resour 12:771–778. https://doi.org/10.1111/j.1755-0998.2012.03137.x

Gurney WSC, Nisbet RM (1979) Ecological stability and social hierarchy. Theor Popul Biol 16:48–80

Hartig F (2020) DHARMA: residual diagnostics for hierarchical (multi-level/mixed) regression models. R package version 0.3.3.0. https://CRAN.R-project.org/package=DHARMA

Koski J, Xie H, Olson I (2015) Understanding social hierarchies: the neural and psychological foundations of status perception. Soc Neurosci 10:527–550. https://doi.org/10.1080/17470919.2015.1013223

Lenth RV (2021) emmeans: estimated marginal means, aka least-squares means. R package version 1.5.4. https://CRAN.R-project.org/package=emmeans

Peakall R, Smouse PE (2012) GenAIEx 6.5: genetic analysis in Excel. Population genetic software for teaching and research—an update. J Bioinform 28:2537–2539. https://doi.org/10.1093/bioinformatics/bts460

R Core Team (2020) R: a language and environment for statistical computing. R Foundation for Statistical Computing, Vienna

Reed C, Branconi R, Majoris J, Johnson C, Buston PM (2019) Competitive growth in a social fish. Biol Lett 15:1–4. https://doi.org/10.1098/rsbl.2018.0737

Reinke B, Miller DAW, Janzen FJ (2019) What have long-term field studies taught us about population dynamics? Annu Rev Ecol Evol Syst 50:261–278. https://doi.org/10.1146/annurev-ecolsys-110218-024717
Robbins MM, Robbins AM, Gerald-Steklis N, Steklis HD (2005) Long-term dominance relationships in female mountain gorillas: strength, stability and determinants of rank. *Behaviour* 142:779–809. https://doi.org/10.1163/1568539054729123

Rueger T, Barbasch TA, Wong MYL, Jones GP, Buston PM (2018) Reproductive control via the threat of eviction in the clown anemonefish. *Proc R Soc B* 285:1–6. https://doi.org/10.1098/rspb.2018.1295

Saenz-Agudelo P, Jones GP, Thorrold SR, Planes S (2015) Mothers matter: contribution to local replenishment is linked to female size, mate replacement and fecundity in a fish metapopulation. *Mar Biol* 162:3–14. https://doi.org/10.1007/s00227-014-2556-x

Salis P, Roux N, Huang D, Marcionetti A, Mouginot P, Reynaud M, Salles OC, Salamin N, Pujol B, Parichy D, Planes S, Laudet V (2021) Thyroid horomones regulate the formation and environmental plasticity of white bars in clownfishes. *PNAS*. https://doi.org/10.1073/pnas.2101634118

Salles OC, Saenz-Agudelo P, Almany GR, Berumen ML, Thorrold SR, Jones GP, Planes S (2016) Genetic tools link long-term demographic and life-history traits of anemonefish to their anemone hosts. *Coral Reefs* 35:1127–1138. https://doi.org/10.1007/s00338-016-1485-1

Thompson VJ, Munday PL, Jones GP (2007) Habitat patch size and mating system as determinants of social group size in coral-dwelling fishes. *Coral Reefs* 26:165–174. https://doi.org/10.1007/s00338-006-0181-y

Whiteman EA, Cote IM (2004) Monogamy in marine fishes. *Biol Rev* 79:351–375. https://doi.org/10.1017/S1464793103006304

Wickham H (2016) ggplot2: Elegant Graphics for Data Analysis. Springer-Verlag, New York, USA

Wong MYL, Buston PM, Munday PL, Jones GP (2007) The threat of punishment enforces peaceful cooperation and stabilizes queues in a coral-reef fish. *Proc R Soc B* 274:1093–1099. https://doi.org/10.1098/rspb.2006.0284

Wong MYL, Munday PL, Buston PM, Jones GP (2008) Monogamy when there is potential for polygyny: tests of multiple hypotheses in a group-living fish. *Behav Ecol* 19:353–361. https://doi.org/10.1093/beheco/arm141

Wong MYL, Uppaluri C, Medina A, Seymour J, Buston PM (2016) The four elements of within-group conflict in animal societies: an experimental test using the clown anemonefish, *Amphiprion percula*. *Behav Ecol Sociobiol* 70:1467–1475. https://doi.org/10.1007/s00265-016-2155-6

**Publisher's Note** Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.