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Dr Rebecca Bathgate

Biography

I am a marine ecologist with research interests in behavioural ecology, animal movement ecology and applied marine conservation biology.

My work typically involves the use of biotelemetry to document the movements and behaviour of marine fishes (e.g. foraging and migrations) that impact on their ecology. Current research projects include (1) the examination of functional and migratory connectivity in marine fishes, in particular their reproductive spawning migrations (2) investigation of the potential for behavioural thermoregulation in coral reef fishes (3) understanding the basis of cooperation betweeen marine fish dyads.

I received my PhD (Marine Biology) in 2013 from James Cook University. In 2015 I was awarded a 3-yr Chancellor's Postdoctoral Research Fellowship at UTS, working with Prof. Bill Gladstone.

Professional

Research Grants and Fellowships:

2016         Isobel Bennett Marine Biology Fellowship, Lizard Isand Reef Research Foundation
2015         Ian Potter Foundation Science Award
2015         Australia’s Integrated Marine Observing System (AATAMS Division) Loan Pool Award
2015-18    Chancellor’s Postdoctoral Fellowship, University of Technology, Sydney

Society memberships: Australian Coral Reef Society, Australian Society for Fish Biology, Fisheries Society of the British Isles

Image of Rebecca Bathgate
Chancellor's Post Doctoral Research Fellow, School of Life Sciences
Marine Biology
 
Phone
+61 2 9514 4087

Research Interests

  • Marine fish behavioural ecology
  • Animal movement ecology
  • Marine conservation biology
  • Biotelemetry and acoustic tracking
  • Fish reproductive behaviour and spawning aggregations
  • Biology and ecology of herbivorous reef fishes

Can supervise: Yes

Journal articles

Goatley, C.H.R., Bonaldo, R.M., Fox, R.J. & Bellwood, D.R. 2016, 'Sediments and herbivory as sensitive indicators of coral reef degradation', Ecology and Society, vol. 21, no. 1.
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© 2016 by the author(s). Around the world, the decreasing health of coral reef ecosystems has highlighted the need to better understand the processes of reef degradation. The development of more sensitive tools, which complement traditional methods of monitoring coral reefs, may reveal earlier signs of degradation and provide an opportunity for pre-emptive responses. We identify new, sensitive metrics of ecosystem processes and benthic composition that allow us to quantify subtle, yet destabilizing, changes in the ecosystem state of an inshore coral reef on the Great Barrier Reef. Following severe climatic disturbances over the period 2011-2012, the herbivorous reef fish community of the reef did not change in terms of biomass or functional groups present. However, fish-based ecosystem processes showed marked changes, with grazing by herbivorous fishes declining by over 90%. On the benthos, algal turf lengths in the epilithic algal matrix increased more than 50% while benthic sediment loads increased 37-fold. The profound changes in processes, despite no visible change in ecosystem state, i.e., no shift to macroalgal dominance, suggest that although the reef has not undergone a visible regime-shift, the ecosystem is highly unstable, and may sit on an ecological knife-edge. Sensitive, process-based metrics of ecosystem state, such as grazing or browsing rates thus appear to be effective in detecting subtle signs of degradation and may be critical in identifying ecosystems at risk for the future.
Smith, S.M., Fox, R.J., Donelson, J.M., Head, M.L. & Booth, D.J. 2016, 'Predicting range-shift success potential for tropical marine fishes using external morphology.', Biology letters, vol. 12, no. 9.
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With global change accelerating the rate of species' range shifts, predicting which are most likely to establish viable populations in their new habitats is key to understanding how biological systems will respond. Annually, in Australia, tropical fish larvae from the Great Barrier Reef (GBR) are transported south via the East Australian Current (EAC), settling into temperate coastal habitats for the summer period, before experiencing near-100% mortality in winter. However, within 10 years, predicted winter ocean temperatures for the southeast coast of Australia will remain high enough for more of these so-called 'tropical vagrants' to survive over winter. We used a method of morphological niche analysis, previously shown to be an effective predictor of invasion success by fishes, to project which vagrants have the greatest likelihood of undergoing successful range shifts under these new climatic conditions. We find that species from the family of butterflyfishes (Chaetodontidae), and the moorish idol, Zanclus cornutus, are most likely to be able to exploit new niches within the ecosystem once physiological barriers to overwintering by tropical vagrant species are removed. Overall, the position of vagrants within the morphospace was strongly skewed, suggesting that impending competitive pressures may impact disproportionately on particular parts of the native community.
Head, M.L., Fox, R.J. & Barber, I. 2016, 'Environmental change mediates mate choice for an extended phenotype, but not for mate quality', Evolution, vol. 71, no. 1, pp. 135-144.
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© 2016, Society for the Study of Evolution.Sexual cues, including extended phenotypes, are expected to be reliable indicators of male genetic quality and/or provide information on parental quality. However, the reliability of these cues may be dependent on stability of the environment, with heterogeneity affecting how selection acts on such traits. Here, we test how environmental change mediates mate choice for multiple sexual traits, including an extended phenotype--the structure of male-built nests - in stickleback fish. First, we manipulated the dissolved oxygen (DO) content of water to create high or low DO environments in which male fish built nests. Then we recorded the mate choice of females encountering these males (and their nests), under either the same or reversed DO conditions. Males in high DO environments built more compact nests than those in low DO conditions and males adjusted their nest structure in response to changing conditions. Female mate choice for extended phenotype (male nests) was environmentally dependent (females chose more compact nests in high DO conditions), while female choice for male phenotype was not (females chose large, vigorous males regardless of DO level). Examining mate choice in this dynamic context suggests that females evaluate the reliability of multiple sexual cues, taking into account environmental heterogeneity.
Fox, R.J., Bellwood, D.R. & Jennions, M.D. 2015, 'Why pair? Evidence of aggregative mating in a socially monogamous marine fish (Siganus doliatus, Siganidae)', Royal Society Open Science, vol. 2, no. 9.
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© 2015 The Authors. Many species live in stable pairs, usually to breed and raise offspring together, but this cannot be assumed. Establishing whether pairing is based on mating, or an alternative cooperative advantage, can be difficult, especially where species show no obvious sexual dimorphism and where the act of reproduction itself is difficult to observe. In the tropical marine fishes known as rabbitfish (Siganidae), half of extant species live in socially monogamous, territorial pairs. It has been assumed that partnerships are for mating, but the reproductive mode of pairing rabbitfish is currently unconfirmed. Using passive acoustic telemetry to track movements of fishes belonging to one such species (Siganus doliatus), we provide the first evidence that paired adult fish undertake highly synchronized migrations with multiple conspecifics on a monthly cycle. All tagged individuals migrated along the same route in three consecutive months and were absent from home territories for 2–3 days just after the new moon. The timing and directionality of migrations suggest that S. doliatus may form spawning aggregations, offering the potential for exposure to multiple reproductive partners. The finding raises fundamental questions about the basis of pairing, mate choice and partnership longevity in this family.
Fox, R.J. & Donelson, J. 2014, 'Rabbitfish sentinels: first report of coordinated vigilance in conspecific marine fishes', Coral Reefs, vol. 33, no. 1, pp. 253-253.
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Fox, R.J. & Bellwood, D.R. 2014, 'Herbivores in a small world: Network theory highlights vulnerability in the function of herbivory on coral reefs', Functional Ecology, vol. 28, no. 3, pp. 642-651.
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Summary: The application of network theory within the field of ecology has predominantly been based around the examination of species interactions (e.g. food webs). Extension of networks to spatial ecology is currently limited, yet the approach has significant potential as a framework for analysing habitat connectivity and ecosystem stability. Examination of network structures characterizing the spatial dynamics of organisms has the potential to highlight the relative robustness or vulnerability of the ecosystem processes they support. On coral reefs, grazing by large herbivorous fishes is critical in maintaining the balance between coral and algae and is widely recognized as a key process in reef ecosystem functioning. However, the spatial dynamics exhibited by roving herbivores, and the implications of these dynamics for the overall stability and resilience of herbivory on reefs are not well understood. Here, we present a novel extension of network theory to the analysis of movements of marine herbivorous fishes within a reef system. Using an array of remote acoustic receivers, over a period of 12 months, we tracked the movements of fishes belonging to the three dominant species of roving herbivore within a particular coral reef community. Analysing these movements in terms of network graph theory, we found that individual fishes clustered their activities within small sections of the available linear reef habitat, and movements within and outside of these home ranges were made along predictable routes. All three species were heavily reliant on particular, well-connected parts of the reef (nodes), mirroring an 'ultra-small-world' network. This underlying dynamic creates vulnerability in the system, making targeted removal by fishing or the degradation of individual pockets of reef habitat more likely to result in a complete collapse in the overall process of herbivory at that particular area of reef. Our results highlight an inherent vulnerability in the moveme...
Fox, R.J. & Bellwood, D.R. 2013, 'Niche partitioning of feeding microhabitats produces a unique function for herbivorous rabbitfishes (Perciformes, Siganidae) on coral reefs', Coral Reefs, vol. 32, no. 1, pp. 13-23.
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Niche theory predicts that coexisting species minimise competition by evolving morphological or behavioural specialisations that allow them to spread out along resource axes such as space, diet and temporal activity. These specialisations define how a species interacts with its environment and, by extension, determine its functional role. Here, we examine the feeding niche of three species of coral reef-dwelling rabbitfishes (Siganidae, Siganus). By comparing aspects of their feeding behaviour (bite location, bite rate, foraging distance) with that of representative species from two other abundant herbivorous fish families, the parrotfishes (Labridae, Scarus) and surgeonfishes (Acanthuridae, Acanthurus), we examine whether rabbitfishes have a feeding niche distinct from other members of the herbivore guild. Measurements of the penetration of the fishes' snouts and bodies into reef concavities when feeding revealed that rabbitfish fed to a greater degree from reef crevices and interstices than other herbivores. There was just a 40 % overlap in the penetration-depth niche between rabbitfish and surgeonfish and a 45 % overlap between rabbitfish and parrotfish, compared with the almost complete niche overlap (95 %) recorded for parrotfish and surgeonfish along this spatial niche axis. Aspects of the morphology of rabbitfish which may contribute to this niche segregation include a comparatively longer, narrower snout and narrower head. Our results suggest that sympatric coexistence of rabbitfish and other reef herbivores is facilitated by segregation along a spatial (and potentially dietary) axis. This segregation results in a unique functional role for rabbitfishes among roving herbivores that of "crevice-browser": a group that specifically feeds on crevice-dwelling algal or benthic organisms. This functional trait may have implications for reef ecosystem processes in terms of controlling the successional development of crevice-based algal communities, reducing their...
Welsh, J.Q., Fox, R.J., Webber, D.M. & Bellwood, D.R. 2012, 'Performance of remote acoustic receivers within a coral reef habitat: Implications for array design', Coral Reefs, vol. 31, no. 3, pp. 693-702.
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Remote monitoring technologies are increasingly being implemented in the marine environment to better understand the movement patterns of taxa. Coral reefs are no exception. However, there is a paucity of information relating to the performance of acoustic receivers on coral reefs. Our results suggest that the detection performance of acoustic receivers may be significantly impacted by the unique nature of the reef environment. This study assessed the performance of passive acoustic receivers on a typical inner-shelf fringing reef, Orpheus Island, on the Great Barrier Reef, Australia. The detection range and diel performance variability of acoustic receivers was assessed using two parallel lines of 5 VR2W receivers spanning 125 m, deployed on the reef base and reef crest. Two 9-mm acoustic transmitters were moored at opposite ends of each receiver line. The working detection range for receivers was found to be approximately 90 m for the transmitter moored on the reef base and just 60 m for the transmitter moored on the reef crest. However, the detection range on the reef crest increased to 90 m when just the reef crest receivers were considered, highlighting importance of optimal receiver deployment. No diel patterns in receiver performance or detection capacities were detected, suggesting that no corrections are required when interpreting nocturnal versus diurnal activity patterns. We suggest that studies aiming for complete coverage of a site within a reef environment will require receivers in close ( < 100 m) proximity, and that the placement depth of receivers must be a major consideration, with shallow receivers exhibiting a greater detection range than those on the reef slope. Our results highlight the challenges imposed by coral reefs for acoustic telemetry and the importance of receiver placement for studies conducted within these habitats. &copy; 2012 Springer-Verlag.
Fox, R.J. & Bellwood, D.R. 2011, 'Unconstrained by the clock? Plasticity of diel activity rhythm in a tropical reef fish, Siganus lineatus', Functional Ecology, vol. 25, no. 5, pp. 1096-1105.
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1.In studies of an organism's functional ecology, key behavioural traits such as foraging periodicity are assumed to be uniform across the species. In particular, the fundamental division between diurnal and nocturnal activity patterns is usually assumed to be a fixed one, with organisms demonstrating physiological traits optimised for a particular diel rhythm. 2.In this study, we explore the activity rhythm of a tropical reef fish, the golden-lined rabbitfish, Siganus lineatus. We make use of acoustic telemetry (manual tracking), combined with underwater observations of feeding behaviour to investigate the diel foraging patterns of S. lineatus, at three sites around the lagoon of Lizard Island, Great Barrier Reef. 3.We found significant differences in the activity patterns of shoreline and reef-based populations of S. lineatus. Individuals inhabiting the boulder-shoreline site foraged during the day and remained stationary in rest holes during the night, whereas individuals from the two reef populations foraged only during nocturnal hours, remaining stationary at the edge of favoured coral bommies during the day. To our knowledge, this represents the first example of a wholesale intraspecific shift in diel activity rhythm for a tropical marine fish. 4.We suggest that S. lineatus is a diurnal nominal herbivore whose biological rhythm has developed the flexibility to be nocturnal. This development may simply represent the masking effects of predation, competition or ontogeny, or it may represent entrainment over an evolutionary time-scale necessary to enable the species to expand its range into the coral reef environment. 5.Either way, the results identify S. lineatus as a potential subject for research into the relative importance of the various biological forces driving divisions along the temporal niche axis and suggest that the species has the potential to provide insights into the impact of biological rhythm plasticity on ecosystem functioning at the ecologic...
Fox, R.J., Sunderland, T.L., Hoey, A.S. & Bellwood, D.R. 2009, 'Estimating ecosystem function: Contrasting roles of closely related herbivorous rabbitfishes (Siganidae) on coral reefs', Marine Ecology Progress Series, vol. 385, pp. 261-269.
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We explored the role of behaviour and trophic ecology in driving differences in ecosystem function between 2 closely related species. We examined the relationships between diet, feeding rate, alimentary tract structure and patterns of digestion for 2 reef herbivores commonly found on the Great Barrier Reef, Siganus doliatus and S. lineatus. Despite their similar morphology, the 2 species exhibited distinct feeding behaviours and significantly different feeding rates, diets and movements of digesta through the alimentary tract. S. doliatus displayed a typical herbivore diurnal feeding pattern, taking an average 9.7 bites min -1 over the main part of the feeding day and with a diet dominated by red thallate algae (primarily Laurencia spp., Eucheuma sp., Halymenia sp. and Graci-laria sp.) and red and green filamentous algae. S. lineatus was not observed taking a single bite from the reef substratum in > 100 h of underwater observations. The stomach contents of S. lineatus were dominated by amorphous organic matter (detritus). Gut passage rates suggest that S. lineatus is feeding nocturnally or during crepuscular periods. We suggest that these 2 species have distinct functional roles, with S. doliatus being a grazer of reef turf algae and S. lineatus primarily a grazer of off-reef detrital aggregates. This versatility of ecosystem function in closely related species provides further evidence that functional roles do not necessarily divide along taxonomic lines. The results highlight the importance of validating ecosystem function on a species-by-species basis. &copy; Inter-Research 2009.
Fox, R.J. & Bellwood, D.R. 2008, 'Remote video bioassays reveal the potential feeding impact of the rabbitfish Siganus canaliculatus (f: Siganidae) on an inner-shelf reef of the Great Barrier Reef', Coral Reefs, vol. 27, no. 3, pp. 605-615.
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Herbivores are widely acknowledged as key elements maintaining the health and resilience of terrestrial and aquatic ecosystems. Understanding and quantifying the impact of herbivores in ecosystems are fundamental to our ability to manage these systems. The traditional method of quantifying the impact of herbivorous fishes on coral reefs has been to use transplanted pieces of seagrass or algae as "bioassays". However, these experiments leave a key question unanswered, namely: Which species are responsible for the impact being quantified? This study revisits the use of bioassays and tested the assumption that the visual abundance of species reflects their role in the removal of assay material. Using remote video cameras to film removal of assay material on an inner-shelf reef of the Great Barrier Reef, the species responsible for assay-based herbivory were identified. The video footage revealed that Siganus canaliculatus, a species not previously recorded at the study site, was primarily responsible for removal of macroalgal biomass. The average percentage decrease in thallus length of whole plants of Sargassum at the reef crest was 54 &plusmn; 8.9% (mean &plusmn; SE), and 50.4 &plusmn; 9.8% for individually presented Sargassum strands (for a 4.5-h deployment). Of the 14,656 bites taken from Sargassum plants and strands across all reef zones, nearly half (6,784 bites or 46%) were taken by S. canaliculatus, with the majority of the remainder attributable to Siganus doliatus. However, multiple regression analysis demonstrated that only the bites of S. canaliculatus were removing macroalgal biomass. The results indicate that, even with detailed observations, the species of herbivore that may be responsible for maintaining benthic community structure can go unnoticed. Some of our fundamental ideas of the relative importance of individual species in ecosystem processes may be in need of re-evaluation. &copy; 2008 Springer-Verlag.
Fox, R.J. & Bellwood, D.R. 2008, 'Direct versus indirect methods of quantifying herbivore grazing impact on a coral reef', Marine Biology, vol. 154, no. 2, pp. 325-334.
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Two methods were used to assess the grazing impact of roving herbivorous fishes across a coral reef depth gradient within Pioneer Bay, Orpheus Island, Great Barrier Reef. The first technique employed was a method traditionally used to quantify herbivory on coral reefs via the (indirect) inference of herbivore impact from biomass estimates and reported feeding rates. The second method (one of a range of direct approaches) used remote underwater video cameras to film the daily feeding activity of roving herbivores in the absence of divers. Both techniques recorded similar patterns and relative levels of herbivore biomass across five reef zones at the study site. Indirect estimates of the grazing impact across the reef depth gradient of the three predominant species of herbivore broadly coincided with levels quantified directly by remote underwater video, indicating that, to a large extent, presence does correspond to function. However, the video data suggested that, for individual species in particular reef zones, the absolute level of impact may be less than that inferred from presence. In the case of the parrotfish Scarus rivulatus, the video recordings suggested that, at the reef crest, an average of 52% (&plusmn;18 SE) of each m 2 area of reef would be grazed each month, compared with an area of 109% (&plusmn;41 SE) suggested by inferring grazing activity from presence alone. Potential biases associated with remote video recorders may explain some of the discrepancy between values. Overall, the results suggest that, for some fish groups, the indirect method of inferring function from presence can provide a good indication of relative levels of herbivore impact across a coral reef. &copy; 2008 Springer-Verlag.
Fox, R.J. & Bellwood, D.R. 2007, 'Quantifying herbivory across a coral reef depth gradient', Marine Ecology Progress Series, vol. 339, pp. 49-59.
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Despite the widely accepted importance of herbivory as a determinant of reef benthic community structure, few studies have examined the relative contributions of individual species to ecosystem processes at the whole reef scale. This study quantifies the grazing impact of individual species of roving herbivorous fishes across an inner shelf fringing reef at Orpheus Island, Great Barrier Reef, Australia. Estimates of roving herbivore impact based on dawn to dusk observations of feeding rates, measurement of bite sizes and relative abundance revealed that the Orpheus Island system was dominated by 3 species: Scarus rivulatus, Chlorurus microrhinos and Siganus doliatus. The estimated impact of all 3 species varied significantly across the reef depth gradient, with the rate of disturbance peaking at the crest and decreasing significantly down the slope and across the reef flat. The estimated species-specific disturbance levels suggested that during the course of a single month 104 % of a square metre area of the reef crest is grazed by S. rivulatus while 40 % is subject to grazing by C. microrhinos. A total of 26 cm 3 of algal material is removed from the same area by S. doliatus. Overall, there was a 240-fold decrease in grazing activity across the reef flat from that at the crest. The pattern of grazing impact of the numerically dominant siganid and scarid fishes was negatively correlated with the distribution of macroalgae across the same reef gradient. The results of the current study provide support for the hypothesis that algal community structure is shaped by levels of herbivory. &copy; Inter-Research 2007.