Reef Fish Community Structure Research Articles

Interplay of management and environmental drivers shifts size structure of reef fish communities.

Countries are expanding marine protected area (MPA) networks to mitigate fisheries declines and support marine biodiversity. However, MPA impact evaluations typically assess total fish biomass. Here, we examine how fish biomass disaggregated by adult and juvenile life stages responds to environmental drivers, including sea surface temperature (SST) anomalies and human footprint, and multiple management types at 139 reef sites in the Mesoamerican Reef (MAR) region. We found that total fish biomass generally appears stable across the region from 2006 to 2018, with limited rebuilding of fish stocks in MPAs. However, the metric of total fish biomass masked changes in fish community structure, with lower adult than juvenile fish biomass at northern sites, and adult:juvenile ratios closer to 1:1 at southern sites. These shifts were associated with different responses of juvenile and adult fish to environmental drivers and management. Juvenile fish biomass increased at sites with high larval connectivity and coral cover, whereas adult fish biomass decreased at sites with greater human footprint and SST anomalies. Adult fish biomass decreased primarily in Honduran general use zones, which suggests insufficient protection for adult fish in the southern MAR. There was a north-south gradient in management and environmental drivers, with lower coverage of fully protected areas and higher SST anomalies and coastal development in the south that together may undermine the maintenance of adult fish biomass in the southern MAR. Accounting for the interplay between environmental drivers and management in the design of MPAs is critical for increasing fish biomass across life history stages.

Reef fish community structure in the waters of small islands Central Bangka Regency

This study aimed to analyze the community structure of reef fish in the small island waters of Central Bangka. The research was conducted in March 2022 in the waters of Bebuar Island, Ketugar Island, Ketawai Island, and Gusung Asam Central Bangka Regency, Bangka Belitung Islands Province. The coral reef survey method uses purposive sampling and the coral reef fish visual census with data analysis of abundance, diversity index, uniformity, and dominance. In-site water quality measurements included six parameters: temperature, salinity, current, brightness, depth, and pH. The results showed that coral reef cover from 44.60 - 87.00% with the medium to very good category. The abundance of reef fish from 1 to 3 individuals/m2 was dominated by 18 species of the Pomacentridae family. The reef fish diversity index ranged from 2.47 to 2.90, including the medium category. The uniformity index value ranged from 0.79 - 0.94, including the high category, indicating that the species found were evenly distributed across all stations. The dominance index value ranges from 0.07 to 0.15, including low, where no species dominates significantly and the fish are evenly distributed. Temperature, brightness, pH, and salinity are factors that support the growth of coral and reef fish. A water current speed of 0.05 – 0.20 m/s is quite helpful in cleaning coral reefs from mud and can supply oxygen. Water conditions were categorized as good and fulfilled the seawater quality standards.

Reef fish community structure in gusung batu lampe, Muara Badak District, Kutai Kartanegara

The existence of coral reefs in Muara Badak makes this ecosystem very attractive as an object of research, especially reef fish. The aim of this research is to determine the structure of the reef fish community in Gusung Batu Lampe, Muara Badak. A reef fish survey was carried out through scuba diving activities, using the video belt transect method at 10 points. The observed reef fish were identified to the genus level and community structure analysis was carried out in the form of diversity, uniformity, and dominancy indexes. The results showed that in total, 3.699 individuals were found consisting of 61 genera of fish from 23 families. The diversity index shows genera diversity, ecosystem stability, and productivity in high conditions. The uniformity index shows the distribution of individuals between each genera was moderately distributed and had no dominancy of particular genera.

The effect of coral transplantation on the community structure of reef fish on Harapan Island, Seribu Archipelago, Jakarta

Coral reef degradation in Indonesia is increasingly alarming. For this reason, efforts are needed to rehabilitate coral reef ecosystems. In this study, we explained the effect of coral transplantation on the structure of coral fish communities in the waters of Harapan Island, precisely on Rosa and Pamegaran Island, Seribu Archipelago National Park. The study of the reef fish community structure was carried out for 8 weeks from February 2019 to April 2019. This study was conducted by scuba diving to dive directly into the coral transplant sites. During the study period, a total of 35 species (14 families) were observed. There is an increase in fish abundance per 50m² which is significant over time for 8 weeks of observation (α 0.05). Significant differences in abundance of reef fish also occurred between the two islands (α 0.05), indicating that differences in the depth of the location of coral transplants can also affect the abundance of reef fish. It can be concluded that coral transplantation efforts succeeded in increasing the abundance of individual reef fish on both coral transplantation islands.

A Habitat‐Based, Fishery‐Independent Survey Using Actively Fished Hooked Gear Successfully Characterizes Reef Fish Populations in the Eastern Gulf of Mexico

AbstractRecognized limitations of fishery‐dependent data under rapidly changing management regimes have resulted in significant effort during recent years to improve the availability of fishery‐independent data in the southeastern United States. These fishery‐independent surveys target numerous species and habitats with various sampling methods, including the use of trawls, longlines, gill nets, traps, and visual surveys. Although passively fished hooked gear (e.g., longlines) are often used to assess the abundance and life history of managed reef fishes, such types of gear are often limited by the habitats they can fish effectively and are species selective. To address these shortcomings, we developed and implemented an actively fished approach to provide fishery‐independent data: the repetitive timed‐drop hooked‐gear method (RTD method). Despite the high degree of standardization applied to the RTD method, important questions remain as to whether active fishing imparts strong angler variability that may reduce the utility of survey data. Accordingly, we analyzed data from 2014 to 2018 to evaluate potential angler bias and how angler‐associated variability compares to other factors often thought to be important predictors of reef fish abundance and community structure. During this study, 962 stations were sampled, representing a variety of artificial and natural reef habitats. In total, 5,770 fish were caught, representing 92 taxa. Sampling was conducted by 103 unique anglers, including 42 commercial or charter fishers and 61 scientists. Results from both population‐ and assemblage‐level analyses found that most of the variability in the catch could be explained by hook size, habitat, water depth, and year. Angler type was rarely correlated with reef fish abundance or assemblages. Our analyses suggest that the RTD method is effective in gathering fishery‐independent abundance and life history data for reef fishes in the eastern Gulf of Mexico and that the resulting data are not strongly biased by an angler effect.

Tracking widespread climate-driven change on temperate and tropical reefs

Warming seas, marine heatwaves, and habitat degradation are increasingly widespread phenomena affecting marine biodiversity, yet our understanding of their broader impacts is largely derived from collective insights from independent localized studies. Insufficient systematic broadscale monitoring limits our understanding of the true extent of these impacts and our capacity to track these at scales relevant to national policies and international agreements. Using an extensive time series of co-located reef fish community structure and habitat data spanning 12 years and the entire Australian continent, we found that reef fish community responses to changing temperatures and habitats are dynamic and widespread but regionally patchy. Shifts in composition and abundance of the fish community often occurred within 2 years of environmental or habitat change, although the relative importance of these two mechanisms of climate impact tended to differ between tropical and temperate zones. The clearest of these changes on temperate and subtropical reefs were temperature related, with responses measured by the reef fish thermal index indicating reshuffling according to the thermal affinities of species present. On low latitude coral reefs, the community generalization index indicated shifting dominance of habitat generalist fishes through time, concurrent with changing coral cover. Our results emphasize the importance of maintaining local ecological detail when scaling up datasets to inform national policies and global biodiversity targets. Scaled-up ecological monitoring is needed to discriminate among increasingly diverse drivers of large-scale biodiversity change and better connect presently disjointed systems of biodiversity observation, indicator research, and governance.

Oceanographic influences on reef fish assemblages along the Great Barrier Reef

Along the Great Barrier Reef, multi-year fish and oceanographic data were integrated to determine the shelf-scale relationship between oceanographic and environmental variables with reef fish assemblage structure. We used data from long-term monitoring of reef fishes sourced from underwater visual surveys and baited remote underwater video stations, combined with a regional hydrodynamic model, multi-year mooring observations, and surface drifting buoy trajectories. Multivariate analyses revealed distinct latitudinal splits in reef fish assemblages, which aligned spatially with the lagoonal branch of the East Australian Current. This lagoonal current flows onto the continental shelf in the central Great Barrier Reef (∼18-19°S), moves poleward within the lagoon, and exits out the Capricorn Channel (∼23°S). We used oceanographic data to characterize the lagoonal current and its seasonal variability, showing that the current reached its maximum strength during the peak reef fish spawning period in austral spring and summer. The shelf-scale structure in reef fish assemblages was best explained by the orientation angle from reef fish sites to the lagoonal current. The results indicate that the prevailing oceanographic patterns may enhance or restrict larval dispersal and contribute to maintaining distinct mesoscale reef fish communities. These findings provide insights for managing marine populations, and we consider how climate projections could influence large-scale ocean currents and environmental gradients and impact broad-scale reef fish community structure.

Environmental DNA biomonitoring reveals seasonal patterns in coral reef fish community structure

Coral reef fish populations are declining due to multiple factors including habitat destruction, overfishing, and climate change. While these can include seasonal impact, seasonal changes can also be a confounding factor, so that seasonal monitoring is essential for detecting true temporal changes in fish community abundance and composition. However, seasonal monitoring is rarely implemented. The aim of this study was to detect the seasonal patterns of coral reef fish community structure around Tidung Kecil Island, Indonesia, using eDNA metabarcoding (eDNA) and underwater visual census (UVC). The UVC identified 32 species belonging to 10 families in the rainy season and 29 species belonging to 7 families in the dry seasons. The eDNA metabarcoding identified 209 species belonging to 56 families and 27 species belonging to 17 families in the rainy and dry seasons, respectively. Based on eDNA metabarcoding data, coral reef fish abundance and community composition differed significantly between seasons (Mann Whitney, p < 0.01), while the UVC method did not detect these seasonal differences (Mann Whitney, p > 0.05). UVC and eDNA data both showed a predominance of omnivorous fishes in the rainy season and carnivorous fishes in the dry season. Ecological indices did not differ significantly between seasons for the two used methods, although the species making the highest contributions to the similarity (SIMPER) analysis differed between methods. Overall, this study confirms the premise that eDNA metabarcoding can be an effective tool for monitoring seasonal variation in coral reef fish communities.

The COVID-19 pandemic has altered illegal fishing activities inside and outside a marine protected area

The global COVID-19 pandemic has presented a unique opportunity to explore the consequences of illegal exploitation on wildlife communities, as it continues to have wide-reaching impacts on multiple sectors, including local and national economies, international trade, and conservation enforcement1. The ongoing reductions in monitoring and enforcement during the pandemic have allowed increased opportunities for illegal, unreported, and unregulated activities, particularly for small-scale fisheries2. Even before the pandemic, policymakers and fisheries managers intent on controlling illegal fishing activities established marine protected areas (MPAs) that restrict or prohibit fishing3. Unfortunately, non-compliance with MPAs is often the rule rather than the exception, and less than 10% of the world’s MPAs have managed to effectively reduce infringement4. The COVID-19 pandemic has exacerbated these management challenges: a recent review of MPAs worldwide has revealed a general decline in tourism revenue to operate park services during the pandemic, especially revenue needed for supporting personnel to monitor, patrol, and enforce restrictions2. Here, we compile infraction records of illegal fishing activities by both professional (commercial) and amateur (recreational) boats inside and outside of the Tupinambás Ecological Station and the Alcatrazes Wildlife Refuge (Figure 1A), notable for its high reef-fish biomass and diversity in the Southwestern Atlantic5. We show that illegal exploitation has shifted since the onset of the pandemic, targeting larger, higher-value species that contribute disproportionately to the structure and function of reef-fish communities in the region.

Limited human access is linked to higher effectiveness in a marine sanctuary

Marine Protected Areas (MPAs) are a widely used tool for coral reefs conservation, but massive tourism activities inside MPAs worldwide can challenge their effectiveness. This study investigated the role of different levels of protection strictness (no-entry, low and high tourism-allowed zones) set for a marine sanctuary in shaping benthic cover and reef fish community structure in the richest and largest coral reef system of the Southwestern Atlantic. Reef fish community structure and benthic cover differed between protection levels. No-entry zones showed significant higher coral coverage and biomass of piscivores and herbivores than tourism-allowed zones. Highest differences were found between no-entry and high tourism intensity zones. Despite the fact that protection from fishing by itself can ensure conservation benefits, we show here that the establishment of no-entry zones improve MPAs effectiveness.

Reef fish community structure along the southeastern US Atlantic continental shelf break and upper slope appears resistant to increasing lionfish (Pterois volitans/miles) density

Temperate reefs host diverse fish communities along the southeast United States Atlantic coast (SEUS), yet the sustainable management of reef fishes faces myriad challenges. One challenge has been the introduction of Indo-Pacific lionfish (Pterois volitans/miles; hereafter "lionfish"), which have spread quickly throughout the SEUS since their introduction in the late 1900s. We analyzed long- term (2001–2019) video data along the continental shelf break and upper slope (45–125 m deep) of the SEUS to assess changes in lionfish densities over time, characterize reef fish community structure, and determine if native reef fish community structure has changed due to lionfish. Lionfish densities increased substantially during the study, from zero individuals observed in 2001 to approximately 1.2 individuals observed per 100 m 3 (and present in all included transects) by 2019, yet no fish community metrics were negatively related to lionfish density. Demersal habitat influenced fish community structure more than any other variable examined, with more individuals and different fish communities occurring on high-relief compared to low-relief hardbottom habitats. The effects of latitude, depth, and bottom temperature on reef fish community structure were generally weak or nonexistent. Although previous empirical work has found that lionfish negatively affect native fishes at small scales (&lt;30 km2), it is unclear why we did not find similar results in our larger- scale study. It may be related to vagaries of the spatial scale of observation, lionfish effects being primarily limited to high- relief habitats, time lags, or lionfish densities not being high enough yet to cause observable ecological effects.

Reef fish community structure and its association with Lifeform coral in the core zone of the Anambas islands Marine Tourism Park (MTP)

Reef fish are one of the biotas that live in coral reef ecosystems, and their lives depend on the condition of coral reefs. Reef fish communities have a close relationship with coral reefs as their habitat. Collecting data on reef fish and coral growth forms using the underwater visual census (UVS) method and methods point intercept transect (PIT). The results of the identification of coral growth forms found 10 growth forms. The most abundant group of fish in the core zone waters of the Anambas Islands was the omnivorous group of fish found as many as 14,924 ind/250m2. The uniformity index value is obtained by the criteria for a stable uniformity index. The cluster analysis results showed that the similarity index of 43% was found in three groups of entities. The correspondence analysis results found three groupings of reef fish based on their association with coral growth forms.

Reef fish community structure in the islands of Paraja Bay, Pandeglang District, Banten, Indonesia

Abstract. Mujiyanto, Sugianti Y, Afandy YA, Rahayu R, Bidikusuma RA, Nasriri AS, Syam AR, Purnaningtyas SE. 2021. Reef fish community structure in the islands of Paraja Bay, Pandeglang District, Banten, Indonesia. Biodiversitas 22: 4402-4413. Paraja Bay waters have five small islands that coexist with Ujung Kulon National Marine Park and act as a buffer zone for the diversity of fishery resources. This study aimed to assess the reef fishes community structure at small islands in Paraja Bay. Observations were made in 20 locations during August and September 2019 in the five small islands. Reef fishes community structure showed 106 species as included major group (54 species), indicator group (24 species) and target group (28 species), among five small islands, i.e. Badul, Mangir, Oar, Sumur and Umang Islands. The highest reef fishes abundance was founded in Umang Island waters. Several target fish species recorded during the study were mature fish (such as those targeted by fishermen). Only a small proportion were juveniles. Reef fish community structure was categorized as stress community to stable community with its indication was low diversity value, high evenness index, and low dominance. The low diversity index value illustrates that the level of uniformity of reef fish species in Paraja Bay waters is high. This condition is evidenced by each coral fish group's evenness index included in the main species group around 0.93 to 0.98. The target species is 0.88 to 0.99.

Environmental biomonitoring of reef fish community structure with eDNA metabarcoding in the Coral Triangle

Environmental biomonitoring of reef fish community structure with eDNA metabarcoding in the Coral Triangle

Coral reef ecosystems condition prediction after tsunami based on previous reef fish community structure and benthic coverage surveillance on Sumur, Banten

Patterns of community structure within coral reefs ecosystems are strongly influenced by a catastrophe such as a tsunami. Sumur is one of the coastal regions affected the most by the Banten Tsunami in December 2018. This research aims to predict coral reef ecosystem conditions after a tsunami based on the reef fish community structure and benthic coverage in the previous month. The research was conducted on every island around Sumur coastal region. Reef fish specimens were sampled using underwater visual census, and benthic coverage was taken with quadrats for Coral Point Count Estimation (CPCe). Overall coral condition assessed by conservation value determined through coral morphology. The highest coral coverage was found in Sumur, Southwest Oar, and North Badul. Nearly all sites have a high diversity reef fish community, with the highest abundance and species richness found in West Umang and North Badul. Badul island, Mangir island, and Cigorondong were categorized as the locations with coral reef ecosystems with the highest stress-tolerators. Most areas with this high stress-tolerator are predominated by coral massive and sub-massive and have higher endurance than other sites. Post-catastrophe, reef fishes will shift to the sites where most coral reef-building has survived, especially reef fishes with territorial behaviour.

The study of reef fish community in the outer islets of Sekotong Bay, Indonesia

The northern region of Sekotong Bay is well known for its secluded, and it potentially provides a unique habitat for the coral reef ecosystem. There are only two islets located in that outermost area, namely Gili Rengit and Gili Layar. This study aims to describe the reef fish community structure in both islands. The study was conducted in the northern and southern parts of each islet using UVC (Underwater Visual Census) method along a 50×5 m belt transect. A total of 64 species of reef fish from 18 families were identified. The majority of fish found were resident obligate and dwellers. Moderate diversity index, as well as the low presence of indicator and targeted fish species, indicates the susceptible stability of reef fish community in the outer islet of Sekotong Bay.

Effectiveness of Philippine Nationally Managed Marine Reserves in Improving Biomass and Trophic Structure of Coral Reef Fish Communities

Many studies have examined the performance of locally managed marine reserves in the Philippines but the effectiveness of nationally managed marine reserves under the National Integrated Protected Areas System (NIPAS) Act is poorly understood. This study assessed the biomass and trophic structure of reef fishes inside and outside marine reserves from seven NIPAS seascapes. These were compared to other protected seascapes being proposed for inclusion under the NIPAS. Total fish biomass was higher inside marine reserves than outside; however, the effect of protection was not evident when total biomass of commercially valued families was compared. Furthermore, the total biomass of commercially important fishes was lower in NIPAS reefs and fell below threshold values for sustaining fisheries. No difference in trophic structure was found between inside and outside marine reserves in both NIPAS and non-NIPAS reefs. In addition, the relative biomass of predatory fishes (trophic levels ≥ 4) was smaller in reefs with low fish biomass (<25 mt km−2; which describes many NIPAS reefs), than those with higher total fish biomass. The overfished state and depauperate predator biomass of NIPAS reefs may be attributed to poor enforcement of no-take regulations and lack of stakeholder engagement, suggesting the need for improved management.

Coral Reef Fishes Biodiversity In Pahawang Island,Pesawaran District Lampung

The components of coral reef ecosystem can be described by the unique regulation in community level. Coral reef fishes use coral reef as their habitat and they highly depend on coral reef health. Otherwise, the condition of coral reef health can be predicted by the biodiversity of coral reef fishes. The research aim was describe communities differences between two explored area in marine tourism spots in Pahawang Island. This research was conducted on November 2019 at two stations on the coral reefs ecosystem of Pahawang Island represented the two quitely different area, the marine tourism and the visitor areas. The coral reef fishes were observed by using visual census method with a Line Transect length of 30 meters and a visibility of 2.5 meters left and right of the transect. Coral reef fish community structure was measured by diversity, similarity, and dominancy indexes. A total of 1.940 coral reef fish species from 13 families were recorded. Pomacentridae is the most speciose family (1.091 species), followed by Siganidae (308 species) and Labridae (166 species). Biodiversity of coral reef fishes at Pahawang Island showed results diversity index (H') in both observation stations classified as medium with a low dominance index value (C) and similarity index (E) at both stations classified as high, presumably as a result of tourism activities. The diversity index at station 2 has a greater value than station 1 as a tourist area with diving and snorkeling tourism activities, at station 2 there are more types or genus of reef fish, compared to station 1.

Isolation promotes abundance and species richness of fishes recruiting to coral reef patches

Habitat area and fragmentation are recognised as important factors that influence population size, community structure and extinction risk. Abundance and species richness universally increase with habitat area. However, the effects of different aspects of habitat fragmentation, including variation in patch size, number and isolation are often not distinguished from each other or the overall effects of habitat amount. Here we experimentally tested predictions concerning the effects of isolation on abundance, species richness and community structure of coral reef fishes colonising patch reefs by constructing clusters of patches of the same number and size, but manipulating reef spacing. Hexagonal clusters of 7 experimental patch reefs (6 edge and 1 central) with 3 levels of isolation (1 m, 5 m, and 15 m spacing) were established at Kavieng, Papua New Guinea and colonisation was recorded after 6 weeks in 2014. We also deployed video cameras to test whether isolation affected the activity of transient predatory fishes. As predicted, isolation had a positive effect on both mean abundance and species richness at both the cluster and patch scale. The cumulative abundance and species richness exhibited linear increases in relation to habitat area within clusters (from 1 to 7 patch reefs), but the slope increased with the degree of isolation. There was some evidence that transient predators remained longer and were more successful when patches were close together, which may explain the lower abundance and richness of juvenile fish assemblages on more aggregated patch reefs. This study demonstrates that while habitat amount is fundamentally important, isolation has significant effects that will need to be distinguished from other aspects of fragmentation when examining the processes structuring reef fish communities.

Seascape Configuration and Fine-Scale Habitat Complexity Shape Parrotfish Distribution and Function across a Coral Reef Lagoon

Structural complexity spanning fine to broad spatial scales can influence the distribution and activity of key organisms within marine ecosystems. However, the relative importance of hard (e.g., corals) and/or soft (e.g., macroalgae) structural complexity for marine organisms is often unclear. This study shows how both broad-scale (seascape configuration of coral structure) and fine-scale habitat complexity (structure height, number of holes, and presence of macroalgae) can influence the abundance and spatial ecology of reef fish. Underwater visual census of fish, surveys of habitats, remote underwater videos, and behavioral observations by following individual fish were used to quantify fine-scale habitat characteristics (e.g., complexity, coral structure height, macroalgae presence) and the abundance, size structure, and behavior (rates of herbivory, tortuosity ratios and total distance travelled) of abundant parrotfish. Both seascape configuration and macroalgae influenced the patterns of fish abundance and rates of herbivory. However, these relationships varied with trophic groups and ontogenetic stages. Abundance of adult and intermediate-phase parrotfishes was positively influenced by densely aggregated coral structures, whereas juvenile abundance was positively influenced by the presence of macroalgae. Foraging path and bite rates of an abundant parrotfish, Chlorurus spilurus, were not influenced by coral structure configuration or height, but the presence of macroalgae increased the bite rates of all juvenile parrotfish. Our results suggest that a combination of seascape configuration, fine-scale habitat complexity, and microhabitat selectivity influence reef fish community structure and foraging behavior, thus altering herbivory. However, these relationships can differ among functional groups of fish and life-history stages. Information on these fish–habitat interactions is critical for identifying habitats that facilitate ecological functions and ensures the successful management and conservation of essential habitats.