scholarly journals Subsistence harvesting by a small community does not substantially compromise coral reef fish assemblages

2017 ◽  
Vol 74 (8) ◽  
pp. 2191-2200 ◽  
Author(s):  
Tyson S. H. Martin ◽  
Rod M. Connolly ◽  
Andrew D. Olds ◽  
Daniela M. Ceccarelli ◽  
Douglas E. Fenner ◽  
...  
Keyword(s):  
Reef Fish ◽  
Fish Assemblages ◽  
Fish Communities ◽  
Marshall Islands ◽  
Fish Biomass ◽  
Small Community ◽  
Fish Community Structure ◽  
Small Communities ◽  
Top Predators ◽  
Subsistence Fishing

Abstract Fisheries usually first remove large predators before switching to smaller species, causing lasting changes to fish community structure. Reef fish provide essential protein and income for many people, and the impacts of commercial and high-intensity subsistence fishing on reef fish are well documented. However, how fish communities respond to low levels of subsistence fishing using traditional techniques (fishing for food, few fishers) is less well understood. We use three atolls in the Marshall Islands as a model system to quantify effects of commercial and subsistence fishing on reef fish communities, compared to a near-pristine baseline. Unexpectedly, fish biomass was highest on the commercially-fished atoll where the assemblage was dominated by herbivores (50% higher than other atolls) and contained few top predators (70% lower than other atolls). By contrast, fish biomass and trophic composition did not differ between pristine and subsistence-fished atolls – top predators were abundant on both. We show that in some cases, reefs can support fishing by small communities to provide food but still retain intact fish assemblages. Low-intensity subsistence fishing may not always harm marine food webs, and we suggest that its effects depend on the style and intensity of fishing practised and the type of organisms targeted.

Community changes of coral reef fishes in Bunaken National Park, North Sulawesi, Indonesia

2013 ◽  
Vol 1 (2) ◽  
pp. 117
Author(s):  
Fakhrizal Setiawan ◽  
Janny D Kusen ◽  
Georis JF Kaligis
Keyword(s):  
Reef Fish ◽  
National Park ◽  
Fish Community ◽  
Time Series Data ◽  
Coral Cover ◽  
Fish Communities ◽  
Reef Fishes ◽  
Series Data ◽  
Fish Community Structure ◽  
Reef Fish Community

In order to look at changes in coral and reef fish communities during the period of 2006 to 2013, this research was carried out at Bunaken National Park (BNP) with 26 observation sites. The existing data and information of reef fish communities in the park generally could not be used as representative for describing the whole region. Percentage of coral cover and fish abundance during the study period shows that Bunaken Island is more similar to other locations. Reef fish community structure as seen from ecological index (H' at all sites being categorized, E category labile and low category C) shows the condition of the reef fish community is still good. Changes in the structure of reef fish communities showed declining conditions compared to 2006, and coral cover continued to decrease compared to 1998 and 2007. Good overall reef fish and coral cover have decreased; it is thought to be related to the pressure in BNP. Some of the pressures in the region were (i) increasing numbers of domestic as well as foreign visitors, (ii) increasing number of residents in the region, as well as the burden of waste and trash from the Bay of Manado. Penelitian dilakukan di Taman Nasional Bunaken (Utara dan Selatan)   pada 26 lokasi  pengamatan untuk menganalisis perubahan struktur komunitas ikan karang melalui kajian dari suatu time series data dari beberapa penelitian sebelumnya. Data primer mengenai ikan-ikan karang diperoleh melalui visual sensus bawah air yang bersamaan dengan observasi terumbu karang menggunakan point intercept transect. Nilai persentase tutupan karang dan kelimpahan ikan menunjukkan bahwa pada lokasi pengamatan Pulau Bunaken paling baik dibandingan lokasi lainnya. Struktur komunitas ikan karang yang dianalisis dengan indeks ekologi menunjukkan indeks keanekaragaman (H’) di semua site masuk kategori sedang, indeks kesamaan (E) kategori labil dan indeks Dominansi (C) kategori rendah. Hasil penelitian ini menunjukkan bahwa kondisi komunitas ikan karang masih baik, sekalipun  perubahan struktur komunitas ikan karang menunjukkan kondisi yang menurun dibandingkan tahun 2006, begitu juga tutupan karang yang terus turun dibandingkan tahun 1998 dan 2007. Secara keseluruhan baik ikan karang maupun tutupan karang mengalami penurunan, hal ini diduga terkait dengan tekanan yang dialami kawasan TN. Bunaken. Salah satu tekanan terhadap kawasan adalah jumlah turis dari dalam maupun luar negeri yang semakin meningkat tiap tahunnya, penambahan jumlah penduduk di dalam kawasan, serta beban limbah dan sampah dari Teluk Manado.

scholarly journals Biodiversity–ecosystem functioning relationships in fish communities: biomass is related to evenness and the environment, not to species richness

2019 ◽  
Vol 286 (1906) ◽  
pp. 20191189 ◽  
Author(s):  
Aurore Maureaud ◽  
Dorothee Hodapp ◽  
P. Daniël van Denderen ◽  
Helmut Hillebrand ◽  
Henrik Gislason ◽  
...  
Keyword(s):  
Species Richness ◽  
Ecosystem Functioning ◽  
Structural Equation ◽  
Fish Assemblages ◽  
Current Knowledge ◽  
Marine Ecosystem ◽  
Experimental Studies ◽  
Fish Communities ◽  
Trophic Levels ◽  
Fish Biomass

The relationship between biodiversity and ecosystem functioning (BEF) is a topic of considerable interest to scientists and managers because a better understanding of its underlying mechanisms may help us mitigate the consequences of biodiversity loss on ecosystems. Our current knowledge of BEF relies heavily on theoretical and experimental studies, typically conducted on a narrow range of spatio-temporal scales, environmental conditions, and trophic levels. Hence, whether a relationship holds in the natural environment is poorly understood, especially in exploited marine ecosystems. Using large-scale observations of marine fish communities, we applied a structural equation modelling framework to investigate the existence and significance of BEF relationships across northwestern European seas. We find that ecosystem functioning, here represented by spatial patterns in total fish biomass, is unrelated to species richness—the most commonly used diversity metric in BEF studies. Instead, community evenness, differences in species composition, and abiotic variables are significant drivers. In particular, we find that high fish biomass is associated with fish assemblages dominated by a few generalist species of a high trophic level, who are able to exploit both the benthic and pelagic energy pathway. Our study provides a better understanding of the mechanisms behind marine ecosystem functioning and allows for the integration of biodiversity into management considerations.

scholarly journals Shallow reef fish communities of South Bahia coast, Brazil

2010 ◽  
Vol 58 (spe4) ◽  
pp. 33-46 ◽  
Author(s):  
Laís de C. T. Chaves ◽  
José de Anchieta C. C. Nunes ◽  
Cláudio L. S. Sampaio
Keyword(s):  
Cryptic Species ◽  
Reef Fish ◽  
Fish Communities ◽  
Abundant Species ◽  
Wide Distribution ◽  
Northeastern Brazil ◽  
Small Scale ◽  
Similar Species ◽  
Fish Community Structure ◽  
Point Counts

This study aims to describe for the first time the fish community structure of five shallow reefs located off the cities of Santa Cruz de Cabrália and Porto Seguro (Araripe-AR, Itacipanema-IT, Alagados-AL, Naufrágio-NA and Recife de Fora Marine Park-RF Reefs), South Bahia, Northeastern Brazil. Fish density and richness were assessed through stationary point counts of 2 m radius for small cryptic species and 3 m for more conspicuous species. A total of 1 802 fishes belonging to 23 families and 54 species were observed. The most abundant species were the pomacentrids Stegastes fuscus and Abudefduf saxatilis. No significant differences were found for species richness or density of conspicuous species, but density of small cryptic species was low on reefs with high bottom rugosity, where there were more holes and crevices available. Herbivores were dominant on AR, AL and RF, invertivores on AL and both groups were dominant on IT. Some habitat variables such as rugosity and benthic cover were strongly correlated to species and sites. High bottom heterogeneity was found among reefs but they still presented similar species composition, richness and density. Within small-scale studies, such similarities in composition and richness are to be expected for reef fish communities, as most of the species concerned have a wide distribution range.

scholarly journals Fishing degrades size structure of coral reef fish communities

2016 ◽  
Author(s):  
James PW Robinson ◽  
Ivor D Williams ◽  
Andrew M Edwards ◽  
Jana McPherson ◽  
Lauren Yeager ◽  
...  
Keyword(s):  
Coral Reef ◽  
Reef Fish ◽  
Fish Community ◽  
Size Structure ◽  
Fish Communities ◽  
Fish Biomass ◽  
Community Size ◽  
Size Spectra ◽  
Coral Reef Ecosystems ◽  
Total Fish

Fishing pressure on coral reef ecosystems has been frequently linked to reductions of large fishes and reef fish biomass. Associated impacts on overall community structure are, however, less clear. In size-structured aquatic ecosystems, fishing impacts are commonly quantified using size spectra, which describe the distribution of individual body sizes within a community. We examined the size spectra of coral reef fish communities at 38 US-affiliated Pacific islands, spanning from near pristine to highly human populated. Reef fish community size spectra slopes ‘steepened’ steadily with increasing human population and proximity to market due to a reduction in the relative biomass of large fishes and an increase in the dominance of small fishes. In contrast, total fish community biomass was substantially lower on inhabited islands than uninhabited ones, regardless of human population density. Comparing the relationship between size spectra and reef fish biomass, we found that on populated islands size spectra steepened linearly with declining biomass, whereas on uninhabited islands size spectra and biomass were unrelated. Size spectra slopes also were steeper in regions of low sea surface temperature but were insensitive to variation in other environmental and geomorphic covariates. In contrast, reef fish biomass was highly sensitive to biophysical conditions, being influenced by oceanic productivity, sea surface temperature, island type, and habitat complexity. Our results suggest that community size structure is more robust than total fish biomass to increasing human presence and that size spectra are reliable indicators of exploitation impacts across regions of different fish community compositions, environmental drivers, and fisheries types. Size-based approaches that link directly to functional properties of fish communities, and are relatively insensitive to abiotic variation across biogeographic regions, offer great potential for developing our understanding of fishing impacts in coral reef ecosystems.

scholarly journals Fishing degrades size structure of coral reef fish communities

2016 ◽  
Author(s):  
James PW Robinson ◽  
Ivor D Williams ◽  
Andrew M Edwards ◽  
Jana McPherson ◽  
Lauren Yeager ◽  
...  
Keyword(s):  
Coral Reef ◽  
Reef Fish ◽  
Fish Community ◽  
Size Structure ◽  
Fish Communities ◽  
Fish Biomass ◽  
Community Size ◽  
Size Spectra ◽  
Coral Reef Ecosystems ◽  
Total Fish

Fishing pressure on coral reef ecosystems has been frequently linked to reductions of large fishes and reef fish biomass. Associated impacts on overall community structure are, however, less clear. In size-structured aquatic ecosystems, fishing impacts are commonly quantified using size spectra, which describe the distribution of individual body sizes within a community. We examined the size spectra of coral reef fish communities at 38 US-affiliated Pacific islands, spanning from near pristine to highly human populated. Reef fish community size spectra slopes ‘steepened’ steadily with increasing human population and proximity to market due to a reduction in the relative biomass of large fishes and an increase in the dominance of small fishes. In contrast, total fish community biomass was substantially lower on inhabited islands than uninhabited ones, regardless of human population density. Comparing the relationship between size spectra and reef fish biomass, we found that on populated islands size spectra steepened linearly with declining biomass, whereas on uninhabited islands size spectra and biomass were unrelated. Size spectra slopes also were steeper in regions of low sea surface temperature but were insensitive to variation in other environmental and geomorphic covariates. In contrast, reef fish biomass was highly sensitive to biophysical conditions, being influenced by oceanic productivity, sea surface temperature, island type, and habitat complexity. Our results suggest that community size structure is more robust than total fish biomass to increasing human presence and that size spectra are reliable indicators of exploitation impacts across regions of different fish community compositions, environmental drivers, and fisheries types. Size-based approaches that link directly to functional properties of fish communities, and are relatively insensitive to abiotic variation across biogeographic regions, offer great potential for developing our understanding of fishing impacts in coral reef ecosystems.

scholarly journals Differences in Reef Fish Assemblages between Populated and Remote Reefs Spanning Multiple Archipelagos Across the Central and Western Pacific

2011 ◽  
Vol 2011 ◽  
pp. 1-14 ◽  
Author(s):  
Ivor D. Williams ◽  
Benjamin L. Richards ◽  
Stuart A. Sandin ◽  
Julia K. Baum ◽  
Robert E. Schroeder ◽  
...  
Keyword(s):  
Reef Fish ◽  
Fish Assemblages ◽  
Human Populations ◽  
Fish Biomass ◽  
Fishing Pressure ◽  
The Pacific ◽  
The Status ◽  
Order Of Magnitude ◽  
National Monuments ◽  
Reference Areas

Comparable information on the status of natural resources across large geographic and human impact scales provides invaluable context to ecosystem-based management and insights into processes driving differences among areas. Data on fish assemblages at 39 US flag coral reef-areas distributed across the Pacific are presented. Total reef fish biomass varied by more than an order of magnitude: lowest at densely-populated islands and highest on reefs distant from human populations. Remote reefs (<50 people within 100 km) averaged ~4 times the biomass of “all fishes” and 15 times the biomass of piscivores compared to reefs near populated areas. Greatest within-archipelagic differences were found in Hawaiian and Mariana Archipelagos, where differences were consistent with, but likely not exclusively driven by, higher fishing pressure around populated areas. Results highlight the importance of the extremely remote reefs now contained within the system of Pacific Marine National Monuments as ecological reference areas.

Recreational fish feeding inside Brazilian MPAs: impacts on reef fish community structure

2012 ◽  
Vol 92 (7) ◽  
pp. 1525-1533 ◽  
Author(s):  
Caroline Vieira Feitosa ◽  
Laís de Carvalho Teixeira Chaves ◽  
Beatrice Padovani Ferreira ◽  
Maria Elisabeth de Araújo
Keyword(s):  
Community Structure ◽  
Reef Fish ◽  
Marine Protected Areas ◽  
Feeding Activity ◽  
Fish Communities ◽  
Daily Basis ◽  
Artificial Feeding ◽  
Fish Community Structure ◽  
Fish Feeding ◽  
Before And After

Although the practice of recreational feeding of fish by tourists is widespread within marine protected areas (MPAs), the ecological consequences of this activity have received little attention. This research aimed to investigate the influence of artificial feeding on reef fish communities of two Brazilian MPAs. Visual censuses were performed in areas not visited by tourists, in order to characterize the natural community structure of each reef system. In the Maracajaú reefs, the effect of artificial feeding was assessed below a moored floating dock found in the area. Stationary visual censuses were carried out before, during and after the fish feeding activity. In the Maragogi reefs, areas with presence and absence of tourism visitation were established. Transect methodology was employed in each of these areas. On both MPAs, fish feeding was a formal activity and occurred on a daily basis during the course of this study. Within the MPAs, 88 species belonging to 40 families were recorded. In Maracajaú, fish, shrimps and squids were provided by the tourists on the floating dock, which favoured mobile invertebrate feeders, whereas in Maragogi, animal ration and human food were used, causing aggregations of omnivores. Differences were observed in terms of abundance between before and after feeding in Maracajaú and between the control and impacted areas of Maragogi. The data are consistent with fish feeding leading to attraction of determined species, causing an increase in their abundance, also indicating that both the type of food and the extension of activity area are important factors determining the effects on fish communities.

scholarly journals Invasive lionfish had no measurable effect on prey fish community structure across the Belizean Barrier Reef

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3270 ◽  
Author(s):  
Serena Hackerott ◽  
Abel Valdivia ◽  
Courtney E. Cox ◽  
Nyssa J. Silbiger ◽  
John F. Bruno
Keyword(s):  
Community Structure ◽  
Reef Fish ◽  
Fish Community ◽  
Fish Communities ◽  
Reef Fishes ◽  
Barrier Reef ◽  
Fish Community Structure ◽  
Prey Fish ◽  
Invasive Lionfish ◽  
Study Sites

Invasive lionfish are assumed to significantly affect Caribbean reef fish communities. However, evidence of lionfish effects on native reef fishes is based on uncontrolled observational studies or small-scale, unrepresentative experiments, with findings ranging from no effect to large effects on prey density and richness. Moreover, whether lionfish affect populations and communities of native reef fishes at larger, management-relevant scales is unknown. The purpose of this study was to assess the effects of lionfish on coral reef prey fish communities in a natural complex reef system. We quantified lionfish and the density, richness, and composition of native prey fishes (0–10 cm total length) at sixteen reefs along ∼250 km of the Belize Barrier Reef from 2009 to 2013. Lionfish invaded our study sites during this four-year longitudinal study, thus our sampling included fish community structure before and after our sites were invaded, i.e., we employed a modified BACI design. We found no evidence that lionfish measurably affected the density, richness, or composition of prey fishes. It is possible that higher lionfish densities are necessary to detect an effect of lionfish on prey populations at this relatively large spatial scale. Alternatively, negative effects of lionfish on prey could be small, essentially undetectable, and ecologically insignificant at our study sites. Other factors that influence the dynamics of reef fish populations including reef complexity, resource availability, recruitment, predation, and fishing could swamp any effects of lionfish on prey populations.

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