Vertical limits of host infestation by gnathiid isopods (Isopoda: Gnathiidae) parasitic on Caribbean coral reef fishes

2020 ◽  
Vol 40 (6) ◽  
pp. 866-871 ◽  
Author(s):  
Matthew D Nicholson ◽  
Gina C Hendrick ◽  
Amber J Packard ◽  
Davis L Strobel ◽  
Clayton Vondriska ◽  
...  
Keyword(s):  
Coral Reef ◽  
Water Column ◽  
Reef Fishes ◽  
Fish Host ◽  
Benthic Habitat ◽  
Coral Reef Ecosystems ◽  
Caribbean Coral Reef ◽  
Host Detection ◽  
Host Fishes ◽  
Fish Hosts

Abstract Parasites play significant roles in the function of ecosystems and can make up a large proportion of overall biomass. Yet, fundamental aspects of their ecology are often understudied relative to other organisms. Gnathiid isopods are the primary ectoparasites of fishes in coral reef ecosystems. While some studies have investigated their host-detection capabilities, the means by which they seek hosts are largely unknown. Gnathiids are benthic and live on the bottom, and all collection efforts involving live hosts have thus far involved traps set at or near the reef substrate. We investigated the distance gnathiids will travel vertically in the water column to attach to a fish host. The majority of gnathiids collected were at or less than 1 m above the reef substrate, and gnathiids were collected in serially diminishing numbers at 2 and 3 m above it. No gnathiids were collected from any fish hosts set more than 3.5 m above the reef substrate. Results suggest that gnathiids will actively seek host fishes in situ and will travel further from their benthic habitat than previously known. By swimming into the water column, gnathiids can exploit larger, highly-mobile fishes, which can serve as a major source of dispersal.

scholarly journals Representative benthic habitat mapping on Lovina coral reefs in Northern Bali, Indonesia

2021 ◽  
Vol 22 (11) ◽  
Author(s):  
Anggita Kartikasari ◽  
TODHI PRISTIANTO ◽  
RIZKI HANINTYO ◽  
EGHBERT ELVAN AMPOU ◽  
TEJA ARIEF WIBAWA ◽  
...  
Keyword(s):  
Coral Reef ◽  
Coral Reefs ◽  
Habitat Mapping ◽  
Benthic Habitat ◽  
Coral Rubble ◽  
Spatial Coverage ◽  
Coral Reef Ecosystems ◽  
Optical Imagery ◽  
Sentinel 2

Abstract. Kartikasari A, Pristianto T, Hanintyo R, Ampou EE, Wibawa TA, Borneo BB. 2021. Representative benthic habitat mapping on Lovina coral reefs in Northern Bali, Indonesia. Biodiversitas 22: 4766-4774. Satellite optical imagery datasets integrated with in situ measurements are widely used to derive the spatial distribution of various benthic habitats in coral reef ecosystems. In this study, an approach to estimate spatial coverage of those habitats based on observation derived from Sentinel-2 optical imagery and a field survey, is presented. This study focused on the Lovina coral reef ecosystem of Northern Bali, Indonesia to support deployment of artificial reefs within the Indonesian Coral Reef Garden (ICRG) programme. Three specific locations were explored: Temukus, Tukad Mungga, and Baktiseraga waters. Spatial benthic habitat coverages of these three waters was estimated based on supervised classification techniques using 10m bands of Sentinel-2 imagery and the medium scale approach (MSA) transect method of in situ measurement.The study indicates that total coverage of benthic habitat is 61.34 ha, 25.17 ha, and 27.88 ha for Temukus, Tukad Mungga, and Baktiseraga waters, respectively. The dominant benthic habitat of those three waters consists of sand, seagrass, coral, rubble, reef slope and intertidal zone. The coral reef coverage is 29.48 ha (48%) for Temukus covered by genus Acropora, Isopora, Porites, Montipora, Pocillopora. The coverage for Tukad Mungga is 8.69 ha (35%) covered by genus Acropora, Montipora, Favia, Psammocora, Porites, and the coverage for Baktiseraga is 11.37 ha (41%) covered by genus Montipora sp, Goniastrea, Pavona, Platygyra, Pocillopora, Porites, Acropora, Leptoseris, Acropora, Pocillopora, Fungia. The results are expected to be suitable as supporting data in restoring coral reef ecosystems in the northern part of Bali, especially in Buleleng District.

scholarly journals Size-specific recolonization success by coral-dwelling damselfishes moderates resilience to habitat loss

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Morgan S. Pratchett ◽  
Vanessa Messmer ◽  
Shaun K. Wilson
Keyword(s):  
Coral Reef ◽  
Habitat Loss ◽  
Reef Fishes ◽  
Host Coral ◽  
Proximate Cause ◽  
Coral Colony ◽  
Colonization Success ◽  
Coral Reef Ecosystems ◽  
Pomacentrus Moluccensis ◽  
Dascyllus Aruanus

Abstract Increasing degradation of coral reef ecosystems and specifically, loss of corals is causing significant and widespread declines in the abundance of coral reef fishes, but the proximate cause(s) of these declines are largely unknown. Here, we examine specific responses to host coral mortality for three species of coral-dwelling damselfishes (Dascyllus aruanus, D. reticulatus, and Pomacentrus moluccensis), explicitly testing whether these fishes can successfully move and recolonize nearby coral hosts. Responses of fishes to localized coral loss was studied during population irruptions of coral feeding crown-of-thorns starfish, where starfish consumed 29 (34%) out of 85 coral colonies, of which 25 (86%) were occupied by coral-dwelling damselfishes. Damselfishes were not tagged or individually recognizable, but changes in the colonization of different coral hosts was assessed by carefully assessing the number and size of fishes on every available coral colony. Most damselfishes (> 90%) vacated dead coral hosts within 5 days, and either disappeared entirely (presumed dead) or relocated to nearby coral hosts. Displaced fishes only ever colonized corals already occupied by other coral-dwelling damselfishes (mostly conspecifics) and colonization success was strongly size-dependent. Despite movement of damselfishes to surviving corals, the local abundance of coral-dependent damselfishes declined in approximate accordance with the proportional loss of coral habitat. These results suggest that even if alternative coral hosts are locally abundant, there are significant biological constraints on movement of coral-dwelling damselfishes and recolonization of alternative coral habitats, such that localized persistence of habitat patches during moderate or patchy disturbances do not necessarily provide resilience against overall habitat loss.

scholarly journals Olfactory responses of coral-reef fishes to coral degradation and crown-of-thorns (Acanthaster planci)

2016 ◽  
Vol 67 (5) ◽  
pp. 605 ◽  
Author(s):  
Amy G. Coppock ◽  
Naomi M. Gardiner ◽  
Geoffrey P. Jones
Keyword(s):  
Coral Reef ◽  
Reef Fish ◽  
Chemical Cues ◽  
Fish Assemblages ◽  
Reef Fishes ◽  
Live Coral ◽  
Acanthaster Planci ◽  
Olfactory Responses ◽  
Olfactory Stimuli ◽  
Coral Reef Ecosystems

Coral degradation is a major threat towards the biodiversity of coral-reef ecosystems, either through the physical effects of environmental change, or biological agents such as crown-of-thorns (Acanthaster planci). Coral loss is leading to significant declines in reef-fish assemblages, particularly those dependent on live coral as settlement sites. Most reef fishes use olfactory stimuli at settlement; however, their ability to detect chemical stimuli from degraded corals or A. planci is unknown. Here, olfactory responses of juvenile reef fishes to the presence of stressed corals and A. planci were tested. Juveniles of eight common coral-associated species were subjected to a series of pair-wise choice tests, where the period of time spent in two differing water sources was noted. All species demonstrated a significant attraction towards healthy coral (≥76%), avoiding cues emitted by stressed coral colonies. When given the choice between a control water (untreated reef water) and water containing chemical cues from A. planci, most species elicited no response. Finally, when given the choice between chemical cues derived from feeding A. planci or the control, all species avoided A. planci (≥70%). Our results indicated that juvenile reef fish are capable of distinguishing the state of coral health, but not directly from disturbance agents.

scholarly journals Coral reef fishes which forage in the water column

1973 ◽  
Vol 24 (1-4) ◽  
pp. 292-306 ◽  
Author(s):  
W. P. Davis ◽  
R. S. Birdsong
Keyword(s):  
Coral Reef ◽  
Water Column ◽  
Reef Fishes ◽  
Coral Reef Fishes

scholarly journals Results from a conservation initiative for parrotfishes in the Colombian Caribbean

2021 ◽  
Author(s):  
Juliana López-Angarita ◽  
María del Pilar Restrepo Orjuela ◽  
Katherine Guzmán Peña ◽  
Dairo Escobar
Keyword(s):  
Coral Reef ◽  
Fish Community ◽  
Coral Cover ◽  
Conservation Status ◽  
Local Communities ◽  
Fish Community Structure ◽  
Local Conservation ◽  
Underwater Visual Census ◽  
Coral Reef Ecosystems ◽  
Caribbean Coral Reef

AbstractParrotfish (Family Scaridae) are a family of herbivorous fishes crucial to coral reef health, particularly for Caribbean reefs due to their declining coral cover. However, despite parrotfish are fully protected in some countries, they are still heavy fished in most of their Caribbean range. The consequences of this targeted fishery in the Colombian Caribbean are not fully understood due to a lack of local conservation and management resources. This research aimed to evaluate and enhance the conservation status and protection of parrotfish among local communities in the National Natural Park Corales del Rosario and San Bernardo. Underwater visual census surveys (UVC) were undertaken to evaluate reef fish community structure, and participatory education campaigns and activities were carried out with local communities to raise awareness about parrotfish ecology and their functional role in conserving Caribbean coral reef ecosystems of Colombia. UVC showed parrotfish to be dominant in the fish community, yet there was evidence of exploitation of large adults by selective fishing. Conflicts exist between the community and environmental authorities because fishing regulations are not clear, and the level of enforcement is insufficient. Parrotfish are sold to tourists, as ‘red snapper’ to fulfil high seafood demand since commercially valuable fish are now scarce. However, following intensive awareness-raising activities developed as part of this study, the community has started to recognize the vital ecological role of parrotfish in coral reef systems, and are suggesting a redrafting of fishing legislation by the environmental authorities, in order to recognise and incorporate the traditional fishing rights of human communities living within the MPA. Lobbying for the protection of parrotfish and inclusion of local communities in decision-making will take time, but this research represents the crucial first steps towards sustainable practice and cooperative alliances in the Colombian Caribbean.

scholarly journals Summer Oxygen Dynamics on a Southern Arabian Gulf Coral Reef

2021 ◽  
Vol 8 ◽  
Author(s):  
Alain de Verneil ◽  
John A. Burt ◽  
Matthew Mitchell ◽  
Francesco Paparella
Keyword(s):  
Coral Reef ◽  
Water Column ◽  
Turbulent Mixing ◽  
Arabian Gulf ◽  
Biogeochemical Model ◽  
Reef Environment ◽  
Production And Consumption ◽  
Coral Reef Ecosystems ◽  
Underlying Causes ◽  
The Tropics

During the summer the Arabian Gulf is the world's warmest sea, also characterized by hypersalinity and extreme annual temperature fluctuations (12–35oC), making it marginal for coral growth. Yet extensive reefs occur in all eight nations bordering the Gulf. Here we present data demonstrating recurrent summer hypoxia events [oxygen concentration (O2) <2 mg l−1] at a reef in the southern Gulf. Currently these episodes are short enough (median 3 h, max 10 h) to preclude mass mortality. Will this always be the case? Predicting future Gulf hypoxia risk for coral reef ecosystems requires diagnosing the underlying causes driving the timing and magnitude of O2 swings. To this end, we compare our data with the output of a simple coupled 1-D water column/biogeochemical model of the reef environment. This allows us to give quantitative estimates of the O2 fluxes produced by photosynthesis both in the water column and within the coral framework, by respiration processes in the benthos, and from the atmosphere. We demonstrate the role of turbulent mixing, and in particular of tides, in shaping the temporal variability of the amplitude of the diel O2 cycle. We find that, in spite of significant turbulent mixing, which maintains the temperature vertically well-mixed, the biological O2 production and consumption is dominant over the atmospheric O2 flux, and is sufficient to generate vertical differences of 1 to 5 mg l−1 between the bottom and 1.5 m above it. While estimating future trends of hypoxia frequency will require further study, the present findings single out the relevant physical and biological processes (and their interplay) which deserve further scrutiny. The Gulf today experiences temperatures expected to occur across much of the tropics by the end of the century, and the observation of recurrent hypoxia events in the Gulf suggests that similar hypoxic phenomena may represent an important, but to date underappreciated, threat to the future of global coral reefs.

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