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Relative abundance of planktonic copepods (calanoids and cyclopoids) vs abundance of benthic copepods (harpacticoids) in 42 gut samples from four species of Acanthemblemaria. A. spinosa is indicated by closed circles and the other species are indicated by open circles. Descending solid line indicates that combined copepods represent 100% of gut contents; descending dashed line indicates 60% of gut contents. Ascending line indicates equivalency of planktonic and benthic copepods.
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In order to determine the extent to which tube blennies depend on food derived from within or outside of the reef system, the diets of Acanthemblemaria spinosa, A. aspera, A. greenfieldi and A. paula were compared with food availability using plankton, benthic and gut sampling. All species fed primarily on copepods, but A. spinosa consumed calanoid...
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Context 1
... o p o r In addition, all the species have very few calanoids in their guts relative to their abun- dance in the water column but A. spinosa, while having fewer calanoids than the water column, has a considerably lesser reduction than the other species. A. spinosa fed prima- rily on plankton whereas the other three species fed primarily on benthos (Fig. 5). For all taxa, the gut-plankton overlap was 0.56 for A. spinosa and 0.09 for the other species combined (t = 14.2, df = 40, P < 0.0001). In contrast, the gut-benthos overlap was 0.29 for A. spinosa and 0.56 for the other species combined (t = 8.29, df = 40, P < 0.0001). There is a positive correlation of percent calanoids in the ...
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Citations
... Several studies have identified differences in the use of dietary resources among reef fishes by using different approaches. Some of these methods include analysis of feeding behavior (e.g., Berumen et al., 2005;Brandl & Bellwood, 2014;Fox & Bellwood, 2013), stomach content analysis (e.g., Ashworth et al., 2014;Clarke, 1999), gut content DNA metabarcoding (e.g., Brandl et al., 2020;Casey et al., 2019;Coker et al., 2023;Leray et al., 2015;Nalley, Donahue, Heenan, & Toonen, 2021;Takahashi et al., 2020), stable isotope analysis (SIA) (e.g., Matley et al., 2017), and a few incorporating multi-method approaches (e.g., Miller et al., 2019;Nagelkerken et al., 2009). Stomach content analysis provides information related to the diversity and composition of an individual's diet at the time of the capture or over the course of hours to days (short-term picture of diet). ...
... Due to their slow movements relative to pelagic copepods, harpacticoid copepods are likely easier to capture as they can be hunted without leaving the protection of the benthos, providing a safer resource (Kramer et al., 2013). Conversely, calanoid copepods found in the diet of P. fridmani sometimes form dense stationary aggregations in the water column (Clarke, 1999;Davis et al., 1992). This provides fish inhabiting cavities of coral walls to prey on the zooplankton within the relative safety of their sheltered environment (Depczynski & Bellwood, 2004). ...
Understanding how mesopredators partition their diet and the identity of consumed prey can assist in understanding the ecological role predators and prey play in ecosystem trophodynamics. Here, we assessed the diet of three common coral reef mesopredators; Pseudochromis flavivertex , Pseudochromis fridmani , and Pseudochromis olivaceus from the family Pseudochromidae, commonly known as dottybacks, using a combination of (i) visual stomach content analysis, (ii) stomach content DNA metabarcoding (18S, COI), and (iii) stable isotope analysis (δ ¹⁵ N, δ ¹³ C). In addition, P. flavivertex is found in two distinct color morphs in the Red Sea, providing an opportunity to analyze intra‐morph differences. These techniques revealed partitioning in the dietary composition and resource use among species. Arthropods comprised the main dietary component of P. flavivertex (18S > 60%; COI > 10%) and P. olivaceus (18S = 57.2%), while P. fridmani ingested predominantly mollusks (18S = 51.3%, COI = 24.6%). Despite being small predators, microplastics were found in the gut content of some of these fishes. Stable isotope analysis showed differences in species' isotopic niche breadth and trophic position. Pseudochromis olivaceus presented the largest isotopic niche (SEA C = 1.61‰ ² ), while P. fridmani showed the smallest isotopic niche (SEA C = 0.45‰ ² ) among species. Although the two techniques used for stomach content analysis did not show differences in the diet within color morphs of P. flavivertex , they differed in the isotopic niche and resource use. Despite our limited sampling, our findings provide evidence of species‐specific differences in the trophic ecology of dottybacks and demonstrate their important role as predators of cryptic invertebrates and small fishes. This study highlights the importance of combining several approaches (short‐term: visual analysis and DNA metabarcoding; and long‐term: isotope analysis) when assessing the feeding habits of coral reef fish, as they provide complementary information necessary to delimit their niches and understand the role that small mesopredators play in coral reef ecosystems.
... Estos resultados podrían estar directamente influenciados por la ecología trófica de las especies. Por ejemplo, en el caso de A. hancocki, se ha reportado previamente sobre los hábitos planctívoros de su género (Lindquist y Kotrschal, 1987;Clarke, 1999). Por lo tanto, es posible que los MH más elevados del fondo favorezcan a organismos con este tipo de alimentación debido a que el zooplancton suele estar más disponible en la parte superior de la columna de agua (Clarke, 1992), en donde se ha observado que la mayor actividad predatoria de los planctívoros se da alrededor de los 1.5 metros por encima del bentos (Motro et al., 2005). ...
Cryptobenthic reef fish (PACB) are a highly diverse and abundant group characterized by fish with an adult body size < 5 cm and a strong association with the benthos. Despite their ecological importance, this group has been poorly studied, and how these fish respond to the three-dimensional structure and habitat complexity (CH) of the benthic environment remains unknown. The objective of this study was to estimate CH through photogrammetric modeling of 3D rugosity and assess relationships with PACB assemblages in three rocky-coral reefs sites in the Eastern Tropical Pacific. Positive and significant relationships between CH and biological variables were found, demonstrating the importance of habitat three-dimensionality for PACB assemblages. However, these relationships were weak and variable and depended greatly on spatial scale and region. Species richness, abundance, and biomass of PACB were significantly correlated to diverse types of benthic cover, but contrary to expectations, coral cover was negatively correlated with PACB richness and abundance. Conversely, rocky substrate was positively correlated with richness, abundance, and biomass, although these results varied depending on the study region. Significant differences were found in biological variables among different microhabitats. Contrary to expectations, significantly higher values were observed in microhabitats composed of rock and massive corals, while the lowest values were observed in branched corals for all biological variables. Differences between regions were evident; however, no clear latitudinal pattern was observed in terms of richness, abundance, and biomass. The findings of this study contribute to the understanding of PACB and serve as a baseline for evaluating responses to future changes in CH.
... This suggests a significant and intuitive interplay between MR traits and diet composition, where energy-and nutrient-rich animal prey permits more expensive metabolic machinery (Dell, Pawar & Savage, 2011). An even finer positive correlation between the quality of planktonic food sources and SMR has been noted in small reef fishes (Clarke, 1999). Acquiring higher quality prey, in turn, may require a more active foraging strategy and thus, a higher metabolic ceiling (MMR) for animals that need to move quickly or at high intensity (Huey & Pianka, 1981;Killen et al., 2016;Barneche & Allen, 2018). ...
... Killen et al., 2010;Metcalfe, Van Leeuwen & Killen, 2016;Pettersen et al., 2016)], species pairs or small groups (e.g. Clarke, 1999;Carey et al., 2013;Seth et al., 2013;Brandl et al., 2022), or across macroecological scales (Anderson & Jetz, 2005;Jetz, Freckleton & McKechnie, 2008;White & Kearney, 2013;Deutsch et al., 2020). Below, we outline a framework for a better integration of MR into community ecology through trait-based approaches. ...
All animals on Earth compete for free energy, which is acquired, assimilated, and ultimately allocated to growth and reproduction. Competition is strongest within communities of sympatric, ecologically similar animals of roughly equal size (i.e. horizontal communities), which are often the focus of traditional community ecology. The replacement of taxonomic identities with functional traits has improved our ability to decipher the ecological dynamics that govern the assembly and functioning of animal communities. Yet, the use of low‐resolution and taxonomically idiosyncratic traits in animals may have hampered progress to date. An animal's metabolic rate (MR) determines the costs of basic organismal processes and activities, thus linking major aspects of the multifaceted constructs of ecological niches (where, when, and how energy is obtained) and ecological fitness (how much energy is accumulated and passed on to future generations). We review evidence from organismal physiology to large‐scale analyses across the tree of life to propose that MR gives rise to a group of meaningful functional traits – resting metabolic rate (RMR), maximum metabolic rate (MMR), and aerobic scope (AS) – that may permit an improved quantification of the energetic basis of species coexistence and, ultimately, the assembly and functioning of animal communities. Specifically, metabolic traits integrate across a variety of typical trait proxies for energy acquisition and allocation in animals (e.g. body size, diet, mobility, life history, habitat use), to yield a smaller suite of continuous quantities that: (1) can be precisely measured for individuals in a standardized fashion; and (2) apply to all animals regardless of their body plan, habitat, or taxonomic affiliation. While integrating metabolic traits into animal community ecology is neither a panacea to disentangling the nuanced effects of biological differences on animal community structure and functioning, nor without challenges, a small number of studies across different taxa suggest that MR may serve as a useful proxy for the energetic basis of competition in animals. Thus, the application of MR traits for animal communities can lead to a more general understanding of community assembly and functioning, enhance our ability to trace eco‐evolutionary dynamics from genotypes to phenotypes (and vice versa), and help predict the responses of animal communities to environmental change. While trait‐based ecology has improved our knowledge of animal communities to date, a more explicit energetic lens via the integration of metabolic traits may further strengthen the existing framework.
... Concurrently, several attempts have been made to quantify the diets of cryptobenthic fishes, but the reported levels of overlap among species have varied extensively. While most studies found separation among cryptobenthic fishes into distinct trophic guilds based on clearly identifiable, broad prey items such as detritus, algae, and copepods (Kotrschal and Thomson 1986;Muñoz and Ojeda 1997;Depczynski and Bellwood 2003;Hernaman et al. 2009), less evidence exists for fine-scale dietary differences among closely related species (Lindquist and Kotrschal 1987;Clarke 1999;Feary et al. 2009). While it is possible that there is little dietary diversification among closely related species, reliable visual identification of prey items from a few milligrams of partially digested, poorly known prey taxa such as micro-invertebrates is difficult and may mask fine-scale differences (Longenecker 2007). ...
... Furthermore, E. altivelis consumed more annelid prey than its congener. The prevalence of copepod prey in A. spinosa is in accordance with previous examinations (Kotrschal and Thomson 1986;Clarke 1999), but A. aspera also ingested a large proportion of annelids. The distinction between the two-tube blenny species mirrors potential reliance on prey from pelagic (copepods) and benthic (annelids) origins (Clarke 1999). ...
... The prevalence of copepod prey in A. spinosa is in accordance with previous examinations (Kotrschal and Thomson 1986;Clarke 1999), but A. aspera also ingested a large proportion of annelids. The distinction between the two-tube blenny species mirrors potential reliance on prey from pelagic (copepods) and benthic (annelids) origins (Clarke 1999). ...
Ecological niches hold critical information concerning the eco-evolutionary dynamics that govern biodiversity and abundance patterns. Cryptobenthic reef fishes account for approximately half of all reef fish species and are an abundant and important group on coral reefs worldwide. Yet, due to their small size and inconspicuous lifestyles, relatively little is known about the ecological niches of most cryptobenthic species. Here, we use gut content DNA metabarcoding to determine dietary niche overlap and prey richness in four sympatric species of cryptobenthic reef fishes in two genera (Acanthemblemaria aspera, A. spinosa, Enneanectes altivelis, and E. matador). Furthermore, we test whether dietary differentiation corresponds with differences in species distribution patterns across twelve sites on the Mesoamerican Barrier Reef in Belize. Our approach reveals dietary partitioning among the four species, which is further supported by low edge density and high modularity in the resulting trophic network. A. spinosa and E. matador consume a significantly higher richness of prey items than their congeners. This result corresponds with non-random distributions and co-occurrence patterns in both species pairs: the two high prey richness species (A. spinosa and E. matador) co-occur more frequently than predicted by chance, but they are exclusive to exposed forereef sites with high wave action. In contrast, their congeners occur across exposed forereef and sheltered backreef sites, but they do not increase in numbers at sheltered sites. Our findings suggest that A. spinosa and E. matador monopolize a wide variety of prey in exposed habitats, but they are unable to meet the energetic demands of their adaptation to high-flow habitats in sheltered areas, possibly due to lower prey availability. This, in turn, indicates strong ecological differentiation among closely related species of cryptobenthic fishes, driven by links between diet, physiology, prey availability, and wave exposure.
... abundance, body size, diet, oceanic island, reef fish, territorial herbivores, tide pool Resource limitation in tide pools (e.g., reduced space, low food availability, restricted number of shelters) usually promote the emergence of strong territorial disputes in order to gain access to the best refuges and feeding areas (Cheney, 2009). In this sense, the colonisation of new areas and the consumption of complementary items may would reduce the intraspecific competition (Clarke, 1999;Ord et al., 2017). For instance, amphibious blennies move into intertidal areas during high tide to avoid intraspecific competition (Ord et al., 2017), whereas tube blennies of the genus canthemblemaria Metzelaar 1919 consume complementary items reducing the competition (Clarke, 1999). ...
... In this sense, the colonisation of new areas and the consumption of complementary items may would reduce the intraspecific competition (Clarke, 1999;Ord et al., 2017). For instance, amphibious blennies move into intertidal areas during high tide to avoid intraspecific competition (Ord et al., 2017), whereas tube blennies of the genus canthemblemaria Metzelaar 1919 consume complementary items reducing the competition (Clarke, 1999). ...
We investigated the feeding rates, agonistic behaviour and diet of two blenny species, Entomacrodus vomerinus and Ophioblennius trinitatis, by direct observation and gut content analysis. Both species coexist in small and shallow tide pools in the St Peter and St Paul's Archipelago, equatorial North Atlantic Ocean. The feeding rate of O. trinitatis was c. 55% higher than E. vomerinus. On the other hand, agonistic rate of O. trinitatis was negatively related to body size, whereas in E. vomerinus was positively related. Both species showed a high diet overlap, in which detritus was the most important food item (86% in O. trinitatis and 80% in E. vomerinus). Feeding activity was more intense during the morning for O. trinitatis but afternoon for E. vomerinus. These behavioural observations support the importance of temporal feeding partitioning as the main strategy allowing species co‐existence in tide pools.
... Spinyhead blennies primarily feed on planktonic calanoid copepods by darting out of their holes (Clarke 1999). In this way, they depend much on food supply through the ambient Communicated by R. Vonk Electronic supplementary material The online version of this article (doi:10.1007/s12526-016-0543-9) contains supplementary material, which is available to authorized users. ...
... The holes can be used to ambush prey since the planktonic copepods are known to show escape reactions during the approach of A. spinosa individuals (Waggett and Buskey 2007). Previous studies have shown that these copepods are denser at 1 m above the reef surface than at 0.2 m (Clarke 1999). Consequently, spinyheads in high locations eat more, grow faster, and have a higher fecundity compared to those at low locations (Clarke 1992). ...
... To satisfy the energy requirements of A. spinosa, the availability of calanoid and cyclopoid copepods should be high (Clarke 1999). Another factor influencing its distribution is the availability of shelter holes (Wilson et al. 2013). ...
The distribution, abundance, and habitat preferences of the spinyhead blenny, Acanthemblemaria spinosa (Perciformes, Blennioidei, Chaenopsidae), were studied on coral reefs along the leeward side of Curaçao, southern Caribbean. The blennies inhabited small holes inside coral, which predominantly consisted of calcareous tubes constructed by coral-associated serpulid worms of the species Spirobranchus giganteus. About 50 % of the fish inhabited holes in dead coral, and the rest had their holes in live corals of eight species. The fishes showed a clustered distribution pattern and their abundance was higher at shallow depths (5 and 10 m) than at 15 m. Although males generally had a larger body size than females and needed larger holes for shelter and guarding eggs, no sexual dominance in hole selection was found. The position of the holes varied in elevation height above the reef floor, which showed a positive correlation with fish size.
... We addressed this question using sea anemones, Anthopleura elegantissima (Brandt), which are abundant on intertidal rocky shores (e.g., Dayton 1971), and which eat a variety of zooplankton, including those with strong escape responses such as copepods (Sebens 1981). In this study, we used calanoid copepods (Acartia spp.) as model prey organisms because they are an important component of the diets of many benthic suspension-feeding organisms (e.g., Lewis 1992;Clarke 1999;Ribes et al. 1999;Heidelberg et al. 2004), and because their swimming behavior in response to various conditions of flow is well-characterized (e.g., Fields and Yen 1997;Buskey et al. 2002). We examined how the turbulent and wavy flow observed in shallow coastal habitats affect (1) encounter, (2) capture, and (3) retention rates of zooplanktonic prey by a passive suspensionfeeding sea anemone. ...
Predators capture prey in complex and variable environments. In the ocean, bottom-dwelling (benthic) organisms are subjected to water currents, waves, and turbulent eddies. For benthic predators that feed on small animals carried in the water (zooplankton), flow not only delivers prey, but can also shape predator-prey interactions. Benthic passive suspension feeders collect prey delivered by movement of ambient water onto capture-surfaces, whereas motile benthic predators, such as burrow-dwelling fish, dart out to catch passing zooplankton. How does the flow of ambient water affect these contrasting modes of predation by benthic zooplanktivores? We studied the effects of turbulent, wavy flow on the encounter, capture, and retention of motile zooplanktonic prey (copepods, Acartia spp.) by passive benthic suspension feeders (sea anemones, Anthopleura elegantissima). Predator-prey interactions were video-recorded in a wave-generating flume under two regimes of oscillating flow with different peak wave velocities and levels of turbulent kinetic energy ("weak" and "strong" waves). Rates of encounter (number of prey passing through a sea anemone's capture zone per time), capture (prey contacting and sticking to tentacles per time), and retention (prey retained on tentacles, without struggling free or washing off, per time) were measured at both strengths of waves. Strong waves enhanced encounter rates both for dead copepods and for actively swimming copepods, but there was so much variability in the behavior of the live prey that the effect of wave strength on encounter rates was not significant. Trapping efficiency (number of prey retained per number encountered) was the same in both flow regimes because, although fewer prey executed maneuvers to escape capture in strong waves, more of the captured prey was washed off the predators' tentacles. Although peak water velocities and turbulence of waves did not affect feeding rates of passive suspension-feeding sea anemones, increases in these aspects of flow have been shown to enhance feeding rates and efficiency of motile benthic fish that lunge out of their burrows to catch zooplankton. Faster, more turbulent flow interferes with the ability of prey to detect predators and execute escape maneuvers, and thus enhances capture rates both for passive suspension-feeding predators and for actively swimming predators. However, prey captured in the mouths of fish are not washed away by ambient flow, whereas prey captured on the tentacles of suspension feeders can be swept off before they are ingested. Therefore, the effects of flowing water on predation on zooplankton by benthic animals depend on the feeding mode of the predator.
... Chaenopsins are significant models for the study of ecology and evolution, in part because they are site attached, often abundant (Thomson and Gilligan, 2002) and readily observed. As a consequence, the ecology, habitat use and mating behavior of several species are relatively well known (e.g., Clarke, 1999;Hastings, 1986Hastings, , 1988aHastings, ,b, 1992aHastings, , 2001aHastings, , 2002Hastings and Galland, 2010;Lindquist, 1980Lindquist, , 1985. Tube blennies occupy shelters in a variety of ecological settings that include rocky reefs, coral reefs, and along the margins of these reefs where sand and shell rubble are common (see Table 1). ...
Phylogenetic relationships within tube blennies (Chaenopsinae) were reconstructed using Bayesian, maximum parsimony and likelihood analyses of multiple molecular markers (mitochondrial DNA: COI; nuclear DNA: TMO-4C4, RAG1, Rhodopsin, and Histone H3) and 148 morphological characters. This total-evidence based topology is well-resolved and congruent across analytical methods with strong support for the monophyly of the Chaenopsinae, all included genera and several internal nodes. A rapid radiation in the early evolution of chaenopsins is inferred from the relatively poor support values for relationships among basal lineages and their divergence into different habitats (rocky reefs, coral reefs and the reef/sand interface). Rates of molecular evolution in chaenopsins, as inferred by divergence among four putative transisthmian geminate species pairs, are rapid compared to other fishes. Conflicts among genetic markers and morphology are especially evident within the genus Coralliozetus, with different species relationships supported by morphology, TMO-4C4, and RAG1 plus Rhodopsin. This study hypothesizes a novel sistergroup relationship between Ekemblemaria and Hemiemblemaria, consistent with morphological, molecular and habitat use data. Our total evidence phylogenetic hypothesis indicates that previously hypothesized morphological characters supporting a close relationship between Hemiemblemaria and Chaenopsis plus Lucayablennius resulted from convergent evolution in these relatively free-swimming blennies.
... Planktonic copepods are more energy-rich than those in the benthos (Clarke, 1999), probably due to their higher lipid content (Sargent and Falk-Petersen, 1988), so D. aruanus may face a choice between a risky, high-profit food source and a safer, less profitable one. One benefit of group membership is reduced predation risk (Booth, 1995; Kent et al., 2006), where a greater level of safety is expected in larger groups due to some combination of simple risk dilution and collective threat detection (Beauchamp, 2003; White and Warner, 2007). ...
Intrapopulation diet specializations may result from the use of different dietary items or foraging tactics by individuals within a single population. The damselfish, Dascyllus aruanus, is a highly site-attached coral reef fish living in size hierarchies among branched corals. The trophic niche width and feeding specialization of this species were explored using stable isotopes and stomach content analyses. Intra-group niche variation was mainly related to fish size. Within social groups, D. aruanus gradually shifted its foraging tactics according to size; smaller fish fed on benthic prey such as isopods and copepods, and the larger fish foraged in the water column on planktonic copepods and larger-sized prey. Group density was found to explain some variation in trophic niche characteristics; greater specialization on prey size was observed in the colony having the highest density. All members of the largest colony foraged more frequently in the water column. Knowing that planktonic copepods are more energy-rich than benthic ones, a positive group-size effect facilitating access to preferred prey is suggested. Group size and group density effects on trophic specialization did not have any impact on body condition, suggesting that the behavioral plasticity of D. aruanus in its foraging strategies permits compensation for the maintenance of body conditions.
... The spatial distribution of these two species may influence their diet, feeding activity, and life histories. For example, spinyheads have a diet consisting primarily of planktonic copepods, while roughheads have a mixed diet of planktonic and benthic copepods (Clarke 1999 ). Moreover , when placed on artificial habitats, both species make more frequent feeding darts, have higher growth rates, and have higher fecundities at 1 m above the reef surface as compared with 0.15 m (Clarke 1992). ...
... Moreover , when placed on artificial habitats, both species make more frequent feeding darts, have higher growth rates, and have higher fecundities at 1 m above the reef surface as compared with 0.15 m (Clarke 1992). This difference could be the result of small-scale variation in plankton density between high and low shelters (Hamner and Carleton 1979; Forrester 1991; Clarke 1999). Clarke (1999) found that during the day (i.e., when blennies feed) planktonic calanoid copepods were more abundant 1–1.5 m above the reef surface than 0–0.5 m above the reef surface, presumably increasing feeding opportunities for fishes occupying higher locations. ...
... al habitats, both species make more frequent feeding darts, have higher growth rates, and have higher fecundities at 1 m above the reef surface as compared with 0.15 m (Clarke 1992). This difference could be the result of small-scale variation in plankton density between high and low shelters (Hamner and Carleton 1979; Forrester 1991; Clarke 1999). Clarke (1999) found that during the day (i.e., when blennies feed) planktonic calanoid copepods were more abundant 1–1.5 m above the reef surface than 0–0.5 m above the reef surface, presumably increasing feeding opportunities for fishes occupying higher locations. Thus, vertical gradients in the availability of planktonic prey correspond with the ob ...
The interaction of flowing water with reef topography creates a continuum of flow microhabitats that can alter species distributions
directly via transport of organisms or propagules, or indirectly by modulating the availability of critical resources. To
examine how water flow affects the distribution and feeding performance of two species of planktivorous tube blennies (Chaenopsidae),
flow speed and turbulence were measured within the feeding areas of Acanthemblemaria spinosa and A. aspera at three sites within Glover’s Reef, Belize. Although co-occurring, A. spinosa occupies topographically high locations (e.g., upright coral skeletons) while A. aspera occupies topographically low shelters in the coral pavement. Boundary layer theory predicts that A. spinosa should experience higher flow (and a higher flux of planktonic food) relative to A. aspera; however, complex topography and oscillatory flow require that this prediction is tested directly in the field. Within each
site, the flow experienced by A. spinosa was, indeed, faster and more turbulent than that experienced by A. aspera at site-specific intermediate wave heights. When waves were small, gentle velocity gradients produced similar flows for the
two species. When waves were high, flow was uniformly fast through the water column due to thinning of the benthic boundary
layer. Plankton availability was similar for the species, with the exception of a greater abundance of harpacticoid copepods
at the shelters of A. aspera. Quantitative behavioral observations suggest that the foraging strategies employed by the two fishes exploit the prevailing
hydrodynamic conditions. For example, A. spinosa, the stronger swimmer of the two, attacks nearly 100% of the time in the water column where it can exploit the higher flux
of plankton associated with faster flows, while A. aspera attacks primarily toward the reef surface where currents are likely to be slower and it can exploit more abundant benthic
prey.
