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Summary of fish morphometrics, fates, maximum distance moved from the aggregation and home range areas
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The aim of the study was to estimate home range areas and distance of movement away from a squaretail coralgrouper (Plectropomus areolatus) spawning aggregation site located within a small-scale 1.5km2 Marine Protected Area (MPA) in Pohnpei, Micronesia. Fifteen P. areolatus were acoustically tagged and re-located within a ca. 50km2 search area over...
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The activity and movement of the Redlip Parrotfish, Scarus rubroviolaceus, near Wawaloli reef, Hawaii (19°43′06″N, 156°03′11″W), was investigated with active and passive tracking techniques from April through November 2007. Site fidelity was determined and home range sizes were measured for 21 individuals. All individuals showed strong diurnal acti...
The coral trout Plectropomus leopardus (Serranidae)forms the major component of the commercial andrecreational line fishery on the Great Barrier Reef(GBR) in Australia (Kailola et al. 1993). Lately, con-cernshavebeenexpressedregardingrapidincreases infishing effort leading to localized depletion of sometarget species (Mapstone et al. 1996), and additi...
Citations
... covering home range habitats, migratory corridors and spawning aggregation sites) of sites to ensure maximum fishery benefits (Krueck et al., 2018). In these cases, the recovery of spawning stock biomass could potentially be promoted for commercially valuable climate-resilient species such as the squaretail coral grouper (Plectropomus areolatus) (Hutchinson and Rhodes, 2010) and the mangrove red snapper (Lutjanus argentimaculatus) (Honda et al., 2016;Honda et al., 2017) within the boundaries of the MPA itself (McClure et al., 2020;. Catches in the wider area could further benefit due to the potential positive impacts of spill-over, a process by which biomass is exported to adjacent fishing grounds (Di Lorenzo et al., 2016). ...
... The spawning aggregates are temporary and disperse after the spawning. However, the home range of groupers is small, and many fish stay close to their aggregation sites after the spawning [22,19] . The aggregation sites are many, and spread over the entire coral reef (the fringing reef (and patch and barrier reefs) extends along the entire coast at a width of more than 1/2 to 1 km), a very vast area. ...
Some reproductive traits, fishery status, and the degree of r-selection of the squaretail coral grouper Plectropomus areolatus (Rüppell, 1830) and the roving coral grouper Plectropomus pessuliferus (Fowler, 1904) in the Red Sea Abstract Some reproductive traits, fishery status, and the degree of r-selection were established in the Red Sea groupers, Plectropomus areolatus and P. pessuliferus, using monthly random samples and secondary data from the previous studies. Aging was done by counting vertebral annuli, and egg count by a colony counter. The average lengths of P. areolatus and P. pessuliferus were 40.76±1.03 and 61.55±2.34cm. Four and seven age groups were observed in the two fish in order. The sex ratio was in favor of females in P. areolatus and males in P. pessuliferus. Both fish aggregated and bred in the summer; the males matured first. The absolute and relative fecundities of P. areolatus were higher than those of P. pessuliferus even though it was the smaller fish. Both fish were heavily fished. P. pessuliferus is relatively less r-selected (r-strategist) than P. areolatus and, therefore, is potentially more vulnerable to fishing pressure. Means of fishery management were suggested.
... Sites with fewer than 10 individuals were excluded to account for potential biases introduced by small sample sizes. To determine if there was significant variation in individual genetic diversity (H O ) between sites, we conducted a one-way ANOVA in rstatix v 0.7.2 (Kassambara 2023) followed by post-hoc Tukeys tests in multcomp v 1.4-25 (Hothorn et al. 2016). Data were assessed for normality and homogeneity of variance and a single P. laevis site (L21) was omitted due to violating assumptions of normality, likely due to the small sample size (n = 14) at this site. ...
Understanding patterns of connectivity across remote atoll reefs is important for managing fishery target species, as they often have small population sizes and limited options for replenishment in the event of localised decline. In this study, we used a comprehensive hierarchical sampling design combined with reduced representation genotyping to compare the population genomics of two sympatric species of coral trout (Plectropomus) within and between three isolated offshore atoll reef systems in north-western Australia. The blue spot coral trout, Plectropomus laevis (8979 single nucleotide polymorphisms—SNPs, 223 individuals, 25 sites) and the passionfruit coral trout, P. areolatus (3702 SNPs, 452 individuals, 20 sites) showed high levels of connectivity within reef systems and restricted connectivity between reef systems, indicating that biological stocks primarily occur at the scale of each reef system. Despite being closely related and co-managed species, inter-specific variation in the magnitude of genetic structure was notable. Plectropomus areolatus at the southern-most reef system display modest genetic structure with populations ~ 450 km to the north, whilst P. laevis at the same location show a level of genetic divergence that reflects deep historical isolation. Our results provide the most comprehensive assessment of genetic connectivity across these remote atoll reefs, facilitating management advice that reflect empirically determined population dynamics for these species. We identify contrasting patterns of genetic connectivity among closely related sympatric species, and highlight the role of extrinsic (e.g., geography/environment) and intrinsic (e.g., life history) factors in shaping population dynamics.
... Local knowledge and published literature (tracking species within the same families) suggests that rock hind and spotted morays exhibit high site fidelity and a small home range. For example, Young & Winn (2003) re corded that G. moringa moved as little as 115 m during nocturnal foraging trips using observational surveys, and Hutchinson & Rhodes (2010) reported a home range for coral trout Plectro pomus areolatus of 0.004 km 2 using active tracking. We also confirmed the fidelity of our focal species using a week-long observational diver survey of G. moringa conducted prior to the VPS (using methods adapted from Abrams et al. 1983). ...
Fine-scale tracking technology has advanced our understanding of aquatic animal behaviour by deriving near-continuous movements of animals ranging in size from small invertebrates to large predatory fish. Commercial fine-scale positioning systems, such as the VEMCO Positioning System, can pinpoint an animal’s location within metres of its true position. While methodological applications of commonly used presence-absence acoustic telemetry have identified factors that can limit array performance, the factors that influence position yield and accuracy and introduce error in fine-scale positioning systems have yet to be synthesised. Evidenced through a systematic review of the literature, we highlight key considerations and potential pitfalls faced when designing and conducting a fine-scale tracking study. Key factors impacting data acquisition are grouped under 4 key categories linked to the study system, species studied, and logistical and technological constraints. Thereafter, in line with these categories, we provide a framework that can be used prior to, during, and post-study to identify sources of error and data loss to optimize system design and acquired results. We provide details on user assessment tools that include a pre-study trial period using fixed tags to assess array geometry and data yield, an in situ checkpoint data download, and a post-study assessment of fixed transmitter performance. We highlight the utility of this framework and integrated assessment tools by presenting a real-world case study that ultimately was compromised. We anticipate that this framework can be used to standardize reporting of essential steps and checks that will generate comparable data for future synthesis, which will further advance fine-scale tracking approaches.
... In subsequent months, male P. areolatus depart along with females following spawning around the full moon. All three species have been shown or observed utilizing common reproductive migratory corridors to reach and depart the FSA site and at last some individuals travel up to 25 km from the FSA to reach home reefs immediately after spawning [62][63][64]. As previously indicated, the species-specific duration of FSA varies, with P. areolatus and E. fuscoguttatus maintaining aggregations over c. 2 weeks during each reproductive month, while the E. polyphekadion FSA currently extends over 5 days or less [10]. ...
... At Ant Atoll, 15 receivers remained deployed along 45 km of outer barrier reef, inclusive of two receivers along the main channel leading into the lagoon (Fig 1). Prior range testing showed that detections of 250 m were common in unobstructed areas [64], similar to that which characterizes the outer reef mooring sites. ...
... Specifically, resident sharks would be expected to receive greater benefits both spatially and temporally from these small set-asides, while for transient and semi-transient sharks, the protections more closely resemble that of aggregating grouper, given the extent of movement and use of common reproductive migratory corridors by these transient spawners. For aggregating groupers, at least some individuals have been detected or captured up to 27 kms from the FSA site [62][63][64], with pathways typically along outer reef areas to reach home reefs. The scale of movement suggests that catchment areas for groupers are on the order of 100s of km 2 [63], thus similar to non-resident sharks. ...
Fish spawning aggregations (FSA) act as biological hotspots that concentrate food and nutrients across a broad trophic spectrum. In Pohnpei (Federated States of Micronesia), 20 female grey reef sharks (Carcharhinus amblyrhynchos) were acoustically tagged at two multi-species grouper (Epinephelidae) FSA to examine the likelihood that these mesopredators utilize FSA as a seasonal food source. Both FSA sites are within small-scale MPAs, thus providing a secondary opportunity to examine their conservation potential during these ephemeral events. Shark movement and residency was gauged against known spatial and temporal grouper reproductive patterns using an array of 15 and 50 acoustic receivers at Ant Atoll and Pohnpei (Island), respectively. Activity space was investigated using Kernel Density estimates of individual sharks, and residency indices (RI) were analyzed based on daily and monthly occurrence at the array. Three distinct residency patterns were identified: transient, semi-transient, or resident (Daily RI <0.40, >0.40 to 0.80, or >0.80, respectively). Generalized linear mixed models (GLMMs) were used to identify biological and environmental factors influencing shark activity space, including month, temperature, shark size, spawning month, and residency pattern. Findings revealed significant changes in average monthly residency indices and kernel densities during spawning months in support of an opportunistic foraging strategy around FSA. Monthly residency was higher during spawning months among semi-resident and transient sharks, while average monthly activity space was concentrated around FSA. Best-fit models for the GLMM indicated that activity spaces were most influenced by month and grouper spawning month. Seven of 20 sharks demonstrated inter-island movement and wide variations in individual movement and spatial requirements were shown. The concentration of sharks and groupers at unprotected FSA sites increases their vulnerability to fishing and supports the need for combined area and non-area management measures to effectively protect these species.
... Our high density array shows that home ranges are much smaller than previous estimations (e.g., Matley et al. 2015) suggesting that sufficient resources, such as food and habitat, are likely to be available within a very small area for P. leopardus (Matley et al., 2015). This also indicates that P. leopardus exhibit patterns of high residency and site fidelity which has also been observed in previous studies (Matley et al., 2015;Zeller, 1997), and other Epinephelid spp, (Hutchinson & Rhodes, 2010). High site fidelity has benefits such as increased foraging efficiency, particularly if resources are distributed unpredictably (Wakefield et al., 2015), but may be maladaptive in environments undergoing acute or long-term change (Faille et al., 2010). ...
Temperature directly affects the metabolic rate and resource requirements of ectothermic animals, which is likely to influence their movement and habitat use. Space use is a fundamental component of an animal’s ecology, and the extent of an animal’s home range has consequences for individual distributions, community structure and ecosystem function. As ocean temperatures continue to rise as a result of global warming, determining the effects of temperature on space use and movement patterns of important fisheries species is vital.
Our aim was to investigate the spatial and temporal variation in space use by a tropical fisheries species, the leopard coralgrouper (Plectropomus leopardus), from two latitudinally distinct locations on Australia’s Great Barrier Reef to determine the potential response of large‐bodied tropical fishes to ocean warming through behavioural modification.
Using passive acoustic telemetry of 36 tagged individuals, we found that both core use areas (50%KUD) and home range extent (95%KUD) varied with respect to location, season, body size and temperature. Average home range extent (95%KUD) for tagged P. leopardus was 0.32 km² at the high‐latitude location (Heron Island) compared to 0.23 km² at the low‐latitude location (Opal Reef). However, core use areas (50%KUD) did not differ significantly between the two locations.
Seasonal differences were also apparent at both locations with P. leopardusshowing contraction in home range extent during the summertime. This effect was most pronounced at the low‐latitude location where home range was significantly reduced during summer when temperatures exceeded 27°C.
Taken together, our findings indicate that higher ambient temperature may elicit a sustained and significant decline in space use by a commercially important reef fish. Given projected increases in ocean temperature due to global climate change, large‐bodied reef fishes may be increasingly constrained in their movement and space use, which will have ramifications for individual fitness, population viability, fisheries productivity and ecological function.
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... To arrive at an aggregation site, fish often use predictable migration routes, such as shelf edges, dropoffs or channels. For example, some resident and transient aggregating species have known migration pathways between spawning and home/feeding sites (Colin 1996, Mazeroll & Montgomery 1998, Whaylen et al. 2004, Hutchinson & Rhodes 2010. Interestingly, there were very few detections on outer aggregation site receivers A and E, indicating fish were not traveling at shallow depths along the wall. ...
Forming spawning aggregations is a critical life-history activity for fish, but it is unclear what physical conditions are associated with fish behavior at specific sites. The habitat, movements and distribution of blackfin snapper Lutjanus fulvus at a monthly aggregation site in Palau were studied using a combination of instruments and approaches, including active/passive acoustics, time-lapse cameras, an autonomous underwater vehicle, current profilers, and high resolution bathymetry. We found that L. fulvus predictably form a large pre-spawning aggregation of an estimated 15 000 fish in a small zone (10s of m) in a tidally forced channel. The aggregation spans 125 m along the northern channel wall, with the highest densities of fish from 9 to 13 m and <15 m from the wall where current velocities are < 0.25 m s⁻¹. The aggregation occurs within an indent in the channel wall where an abrupt change in bathymetry creates a visible eddy-like feature during outgoing tides. The aggregation forms year-round, for 6 d each moon cycle, starting 1 d before the full moon to 4 d after. During the study, 4 tagged fish returned to the site for 6 consecutive lunar cycles; however, residency times within aggregation periods was ~1.5 d on average. Densely aggregated fish were present during the day, but migration patterns of tagged fish revealed regular evening migrations to and from the channel mouth, consistently at the highest tide of the day, a behavior assumed for spawning. These observations reveal some physical processes and biological patterns surrounding the formation and function of fish aggregations.
... Both species typically had high individual core use (.50%) and extent (.80%) vKUD overlap between months. This aligns with the reportedly high site fidelity of P. leopardus (Zeller 1997;Bunt and Kingsford 2014), P. laevis (Matley et al., in press a), P. areolatus (Hutchinson and Rhodes 2010) and other grouper species (e.g. Frias-Torres 2006;Pastor et al. 2009;Waldie et al. 2016). ...
... Contrary to several previous studies (e.g. Zeller 1997;Hutchinson and Rhodes 2010;Matley et al. 2015), there was evidence that P. leopardus behaviour patterns changed with size. The mean depth increased ,2-4 m between the smallest (,400 mm FL) and largest (,625 mm FL) individuals. ...
Prey selection can influence interactions among species, the composition and abundance of prey, and ultimately the movement of energy within the ecosystem. Different species of the exploited coral trout (Plectropomus spp.) often co-occur in reef environments, but their foraging behaviour and ecological niches are largely unknown. To explore niche overlap and resource use of sympatric adult coral trout, stable isotopes (δ13C and δ15N) were quantified for three tissues (muscle, red blood cells, plasma) collected between August 2013 and February 2014 from P. leopardus (n = 117) and P. laevis (n = 36) at four reefs in eastern Australia. Bayesian standard ellipses were used to show that prey selection of P. leopardus varied considerably from P. laevis, particularly the blue-spot colour phase. Size of adult individuals had little influence on δ13C and δ15N values for P. leopardus and both footballer and blue-spot colour phases of P. laevis. Spatio-temporal comparisons of P. leopardus trophic positions, made by adjusting baseline algae and planktonic δ15N at each reef and sampling period, demonstrated that trophic positions varied in time and space, and warrants further investigations. This study highlights that sympatric species of coral trout have distinct ecological roles and will likely react differently to environmental disturbances and/or changes in habitat/prey composition.
... Both species typically had high individual core use (.50%) and extent (.80%) vKUD overlap between months. This aligns with the reportedly high site fidelity of P. leopardus (Zeller 1997;Bunt and Kingsford 2014), P. laevis (Matley et al., in press a), P. areolatus (Hutchinson and Rhodes 2010) and other grouper species (e.g. Frias-Torres 2006;Pastor et al. 2009;Waldie et al. 2016). ...
... Contrary to several previous studies (e.g. Zeller 1997;Hutchinson and Rhodes 2010;Matley et al. 2015), there was evidence that P. leopardus behaviour patterns changed with size. The mean depth increased ,2-4 m between the smallest (,400 mm FL) and largest (,625 mm FL) individuals. ...
Investigating niche overlap in exploited fish species can reveal behavioural information necessary to improve conservation and fisheries management at a species level. The present study examined spatial and dietary overlap between two co-occurring reef fish, namely Plectropomus leopardus and P. maculatus, at an inshore reef in the Great Barrier Reef Marine Park using acoustic telemetry and stable isotopes. Movements of tagged fish within an acoustic array of 19 receivers deployed along a narrow reef portion of Orpheus Island were monitored for up to 3 years. Although space use was similar between species, spatial overlap was rare and P. maculatus (n = 30) was consistently deeper than P. leopardus (n = 32). Dietary overlap between species was high based on overlapping δ15N and δ13C isotopic niches in muscle tissue (n = 20). The complementary stable isotope and acoustic telemetry data revealed these species had similar isotopic niches but distinct space use patterns, which may be a product of com
... In contrast, newly settled P. maculatus have a strong preference for colonies of corymbose Acropora located over sand and/or rubble (Wen et al. 2013a). As juvenile Plectropomus grow, they relocate to more complex habitats, such that fish [10 cm TL are most often found in areas with high coral cover (Connoll and Kingsford 1998;Hutchinson and Rhodes 2010). Plectropomus' strong association with live coral suggest that corals provide shelter, harbour prey, and/or aid foraging tactics. ...
... In all cases, there is a pronounced lunar influence on the timing of aggregation formation, but this varies between species and locations (Table 3). Plectropomus areolatus, for example, spawns around full moon in Micronesia (Hutchinson and Rhodes 2010;Rhodes et al. 2014) and around new moon in Melanesia (Hamilton et al. 2011(Hamilton et al. , 2012. ...
... Plectropomus are cryptic as juveniles but relatively conspicuous as adults, since they are less sedentary than other groupers. Ultrasonic telemetry data indicate that adult fish occupy distinct home ranges in the order of 1-12 ha for P. areolatus and 1-50 ha for P. leopardus, with no apparent relationship between body size or gender and home range area (Zeller 1997;Hutchinson and Rhodes 2010;Matley et al. 2015). Individuals are diurnally active, regularly using a small number of locations within their home-ranges, and often return to the same location each night (Zeller 1997;Bunt and Kingsford 2014). ...
Coral grouper (genus Plectropomus), or coral trout, are members of the grouper family (Epinephelidae) and are one of the largest and most conspicuous predatory fishes on Indo-Pacific coral reefs. They are highly-prized food fishes that are targeted by subsistence, artisanal, commercial and recreational fisheries throughout their geographic range. Plectropomus have broadly similar diets and habitat requirements to other tropical groupers, but typically have faster growth and higher natural mortality rates. Although these characteristics are expected to increase population turnover and reduce innate vulnerability to environmental and anthropogenic impacts relative to other groupers, many Plectropomus populations are in decline due to the combined effects of overfishing and habitat degradation. In many locations, stock depletion from uncontrolled fishing, particularly at spawning aggregation sites, has resulted in local fishery collapse. Therefore, improved management of wild populations is urgently required to ensure conservation and sustainable fisheries of Plectropomus. Where possible, a combination of no-take marine reserves, market-based management approaches, and allocation or resurrection of property rights systems are recommended to complement conventional fishery management actions that limit catch and effort. Additional investment in aquaculture propagation is also needed to reduce fishing pressure on wild stocks and support management initiatives. This global synthesis of information pertaining to the biology, fisheries and management of Plectropomus will assist in guiding future management actions that are attempting to address a range of stressors including fishing, reef habitat degradation, and the escalating effects of climate change.
