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.

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.

Assessing the importance of fishing impacts on Hawaiian coral reef fish assemblages along regional-scale human population gradients

2008 ◽  
Vol 35 (3) ◽  
pp. 261-272 ◽  
Author(s):  
I. D. WILLIAMS ◽  
W. J. WALSH ◽  
R. E. SCHROEDER ◽  
A. M. FRIEDLANDER ◽  
B. L. RICHARDS ◽  
...  
Keyword(s):  
Coral Reef ◽  
Population Density ◽  
Human Population ◽  
Fish Assemblages ◽  
Regional Scale ◽  
Reef Fishes ◽  
Human Populations ◽  
Fish Biomass ◽  
Human Population Density ◽  
General Decline

SUMMARYHumans can impact coral reef fishes directly by fishing, or indirectly through anthropogenic degradation of habitat. Uncertainty about the relative importance of those can make it difficult to develop and build consensus for appropriate remedial management. Relationships between fish assemblages and human population density were assessed using data from 18 locations widely spread throughout the Main Hawaiian Islands (MHI) to evaluate the significance of fishing as a factor potentially driving fish trends on a regional scale. Fish biomass in several groups was negatively correlated with local human population density and a number of lines of evidence indicate that fishing was the prime driver of those trends. First, declines were consistently evident among fish groups targeted by fishers, but not among lightly fished or non-target groupings, which indicates that declines in target groups were not simply indicative of a general decline in habitat quality along human population gradients. Second, proximity to high human populations was not associated with low fish biomass where shoreline structure prevented ready access by fishers. Relatively remote and inaccessible locations within the MHI had 2.1–4.2 times the biomass of target fishes compared to accessible and populous locations, and may therefore function as partial refugia. However, stocks in those areas were clearly far from pristine, as biomass of large predators was more than an order of magnitude lower than at more intact ecosystems elsewhere in the Pacific.

Marine Artificial Reef Research and Development: Integrating Fisheries Management Objectives

2018 ◽  
Keyword(s):  
Reef Fish ◽  
Fish Assemblages ◽  
Spatial Scales ◽  
Construction Materials ◽  
Artificial Reef ◽  
Red Snapper ◽  
Artificial Reefs ◽  
Lutjanus Campechanus ◽  
The Status ◽  
Vermilion Snapper

<em>Abstract</em>.—Reef-fish assemblage structure was compared among multiple artificial and geologic (i.e., naturally occurring hard bottom) habitats in the northeastern Gulf of Mexico during 2014–2016 as part of a larger fishery-independent survey. Baited remote underwater video systems equipped with stereo cameras were deployed (<em>n </em>= 348) on 11 habitat types, classified through interpretation of side-scan sonar imagery. In the video samples, 11,801 fish were enumerated. Nonparametric analysis of reef-fish assemblages detected four clusters related to habitat; assemblages associated with geologic habitats were distinct, whereas the remaining three clusters represented groupings of artificial habitats of different size, scale, and complexity. While many species, including Vermilion Snapper <em>Rhomboplites aurorubens </em>and Red Snapper <em>Lutjanus campechanus</em>, were observed in greater numbers on artificial reef habitats, most species were observed in all habitats sampled. Among artificial reef habitats, the habitat cluster consisting of unidentified depressions, unidentified artificial reefs, construction materials, and reef modules was similar to geologic habitats in supporting larger individuals, specifically Gray Triggerfish <em>Balistes capriscus </em>and Red Snapper. In contrast, the habitat cluster consisting of smaller, generally solitary chicken-transport cages was inhabited by smaller individuals, including smaller Red Snapper. Although geologic reefs are the predominant reef habitat throughout much of the eastern Gulf, artificial reefs are important locally, especially in the Florida Panhandle. Accordingly, continued incorporation of artificial reef habitats within large-scale fishery-independent monitoring efforts is critical to the accurate assessment of the status of reef-fish stocks on broad spatial scales.

The Effects of Fishing on Coral Reef Fish Abundance and Diversity

1996 ◽  
Vol 76 (1) ◽  
pp. 229-233 ◽  
Author(s):  
Maggie Watson ◽  
Dave Righton ◽  
Tim Austin ◽  
Rupert Ormond
Keyword(s):  
Coral Reef ◽  
Reef Fish ◽  
Coral Reef Fish ◽  
Fish Assemblages ◽  
Species Number ◽  
Fishing Pressure ◽  
Artisanal Fishing ◽  
Commercial Species ◽  
Habitat Refugia ◽  
Abundance And Diversity

The effect of artisanal fishing on the abundance and diversity of coral reef fish assemblages was investigated in the Kisite Marine National Park and Mpunguti Marine National Reserve at Shimoni, Kenya. Fishing is prohibited within the Park whereas in the Reserve artisanal fishing using traditional methods is practised. Visual censuses of six representative reef fish families (Chaetodontidae, Lethrinidae, Lutjanidae and Serranidae in 1992 and 1994, and Labridae and Pomacentridae in 1994 only) were undertaken along 250×10 m band transects on two similar pairs of reefs subject to differing fishing pressure. The abundance of commercial species (Lethrinidae, Lutjanidae and Serranidae) was depressed in the Reserve. The unfished butterflyfishes (Chaetodontidae) and damselfishes (Pomacentridae) also showed a greater abundance in the Park than in the Reserve. However, neither species number nor Shannon diversity (H′) of any of these families was affected by fishing pressure. Possible reasons for these findings are discussed. The abundance of commercial species, though not of non-commercial unfished species, increased significantly in the Reserve between 1992 and 1994, suggesting that the unfished Park may be acting as a source of larvae or supply of emigrating adults for the depleted Reserve. The results are comparable with other recent studies describing the effects of fishing pressure and also with those studies detailing the effects of habitat refugia in coral reef areas.

scholarly journals Use of multivariate control charts to assess the status of reef fish assemblages in the Northwestern Hawaiian Islands

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3651 ◽  
Author(s):  
Atsuko Fukunaga ◽  
Randall K. Kosaki
Keyword(s):  
Reef Fish ◽  
Control Charts ◽  
Fish Assemblages ◽  
Confidence Bounds ◽  
Multivariate Control Charts ◽  
National Monument ◽  
Northwestern Hawaiian Islands ◽  
The Status ◽  
Multivariate Control Chart ◽  
Multivariate Control

A distance-based multivariate control chart is a useful tool for ecological monitoring to detect changes in biological community resulting from natural or anthropogenic disturbances at permanent monitoring sites. It is based on a matrix of any distances or dissimilarities among observations obtained from species composition and abundance data, and bootstrapping techniques are used to set upper confidence bounds that trigger an alarm for further investigations. We extended the use of multivariate control charts to stratified random sampling and analyzed reef fish monitoring data collected annually on shallow (≤30 m) reefs across the Northwestern Hawaiian Islands (NWHI), part of the Papahānaumokuākea Marine National Monument. Fish assemblages in the NWHI were mostly stable, with exceptions in the south region (Nihoa, Mokumanamana and French Frigate Shoals) in 2012 and 2015 where changes in the assemblage structure exceeded the upper confidence bounds of multivariate control charts. However, these were due to changes in relative abundances of native species, and potentially related to the small numbers of survey sites and relatively low coral covers at the sites, particularly in 2015. The present study showed that multivariate control charts can be used to evaluate the status of biological communities in a very large protected area. Future monitoring of fish assemblages in the Papahānaumokuākea Marine National Monument should be accompanied by specific habitat or environmental variables that are related to potential threats to its shallow-water ecosystems. This should allow for more detailed investigations into potential causes and mechanisms of changes in fish assemblages when a multivariate control chart triggers an alarm.

Spatial assemblage structure of shallow-water reef fish in Southwest Australia

2020 ◽  
Vol 649 ◽  
pp. 125-140
Author(s):  
DS Goldsworthy ◽  
BJ Saunders ◽  
JRC Parker ◽  
ES Harvey
Keyword(s):  
Shallow Water ◽  
Reef Fish ◽  
Marine Environment ◽  
Fish Assemblages ◽  
Canopy Cover ◽  
Reef Fishes ◽  
Reef Fish Assemblage ◽  
Reef Type ◽  
Present Distribution ◽  
Southwest Australia

Bioregional categorisation of the Australian marine environment is essential to conserve and manage entire ecosystems, including the biota and associated habitats. It is important that these regions are optimally positioned to effectively plan for the protection of distinct assemblages. Recent climatic variation and changes to the marine environment in Southwest Australia (SWA) have resulted in shifts in species ranges and changes to the composition of marine assemblages. The goal of this study was to determine if the current bioregionalisation of SWA accurately represents the present distribution of shallow-water reef fishes across 2000 km of its subtropical and temperate coastline. Data was collected in 2015 using diver-operated underwater stereo-video surveys from 7 regions between Port Gregory (north of Geraldton) to the east of Esperance. This study indicated that (1) the shallow-water reef fish of SWA formed 4 distinct assemblages along the coast: one Midwestern, one Central and 2 Southern Assemblages; (2) differences between these fish assemblages were primarily driven by sea surface temperature, Ecklonia radiata cover, non-E. radiata (canopy) cover, understorey algae cover, reef type and reef height; and (3) each of the 4 assemblages were characterised by a high number of short-range Australian and Western Australian endemic species. The findings from this study suggest that 4, rather than the existing 3 bioregions would more effectively capture the shallow-water reef fish assemblage patterns, with boundaries having shifted southwards likely associated with ocean warming.

Biological Parameters of Three Populations of Triatoma dimidiata s. s. (Hemiptera: Reduviidae) From Western Mexico

2021 ◽  
Author(s):  
Benjamin Nogueda-Torres ◽  
Oziel D Montañez-Valdez ◽  
J G Michel-Parra ◽  
Diana M Martínez-Grant ◽  
J Alejandro Martínez-Ibarra
Keyword(s):  
Pacific Coast ◽  
Median Number ◽  
Sensu Stricto ◽  
Human Populations ◽  
Western Mexico ◽  
Post Feeding ◽  
The Pacific ◽  
High Prevalence ◽  
Vector Borne ◽  
Cruzi Infection

Abstract Chagas disease is a very important vector-borne disease in México, and Triatoma dimidiata sensu stricto (Latreille) is one of the most important vectors of Trypanosoma cruzi Chagas, mainly in southern and central states. In the Pacific Coast states with the highest prevalence of human T. cruzi infection, T. dimidiata s. s. is considered as a secondary vector. However, the vectorial capacity of those populations has not been studied. Therefore, the vector characteristics of three populations of T. dimidiata s. s. in western México were evaluated in this study. The populations were maintained in the laboratory at 27 ± 1°C and 75% ± 5% RH with a 12:12 h (light:dark) regime, fed on rabbits in a fortnight basis. The development times were short (172–238 d), and the number of bloodmeals to molt was low (11). Mortality was moderate (36–45%), the onset of feeding was relatively rapid (0.5–1.7 min), and feedings were extended (&gt;15 min). More than 40% of individuals in most instars defecated in one of three categories: &lt;1 min when feeding (5–37.9%), immediately after feeding (9–28.6%), or in &lt;1 min post feeding (7–25.8%). The median number of laid eggs was high (over 2.5) in the three populations, as were the egg eclosion rates (&gt;86%). Thus, the T. dimidiata s. s. in the three populations are potentially efficient vectors of T. cruzi and could contribute to the high prevalence of infection in human populations in western México.

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