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

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.

2018 ◽  
Vol 47 ◽  
pp. 04003
Author(s):  
Trisna Wahyu A P ◽  
Helmi Mubarak ◽  
Damar Lazuardy Rolian ◽  
Hanson Geraldi Pardede ◽  
Prabowo ◽  
...  

Damage to coral reef ecosystems is a major problem on the islands of Gili Air and Gili Trawangan. This will have an impact on the presence of reef fish in the area. This study aims to look how much relation caused by associated between live coral cover and reef fish in Gili Air and Gili Trawangan island.. This research method using Line Intersept Transect (LIT), Underwater Visual Census and simple linear regression analysis to know the relation. The percentage of coral cover on Gili Air Island and Gili Trawangan Island on reef flats (1-5 m) is 11.75% and 11.67% respectively, on the reef slopes (6-10 m) the percentage is 50.4% and 48.9%. In addition we observed the existence of 11 families reef fish. The abundance of reef fish on Gili Air and Gili Trawangan islands on reefs flat with an average of 0,406 ind / m2 and 0,137 ind / m2, on the reef slope on average - respectively 0,434 ind / m2 and 0,274 ind / m2. The determinant value in Southern part of both island indicates a value close to +1 and in Northern part of both island indicates a value close to -1.


2018 ◽  
Vol 6 (4) ◽  
pp. 333-338
Author(s):  
Fahmi Fahmi ◽  
Supriharyono Supriharyono ◽  
Abdul Ghofar

Ekosistem terumbu karang merupakan kekayaan sumberdaya laut yang memiliki peranan penting dalam mendukung kehidupan berbagai organisme perairan. Salah satu organisme yang memiliki ketergantungan hidup pada terumbu karang adalah ikan karang. Hal ini dikarenakan ikan karang melalui fase hidup sebagian atau seluruhnya di terumbu karang, sehingga terumbu karang menjadi tempat tinggal, tempat mencari makan, tempat berlindung dan tempat berkembang biak.  Penelitian dilaksanakan pada bulan Mei 2017, dengan tujuan untuk mengetahui persentase tutupan karang hidup dan kelimpahan ikan. Serta hubungan persentase tutupan karang dengan kelimpahan ikan karang pada sisi Barat dan Timur Pulau Menjangan Kecil kedalaman 1 dan 3 meter. Metode yang digunakan adalah metode observasi lapangan, dengan metode sampling menggunakan transek garis (line transect) pada data karang dan visual census untuk data ikan sepanjang 25m. Hasil dari penelitian ini menunjukkan bahwa Persentase rata-rata tutupan karang yang diperoleh pada kedalaman 1 meter sisi Barat adalah 73,39%, sedangkan pada kedalaman 3 meter adalah 85,97%. Persentase tutupan karang pada kedalaman 1 meter sisi Timur adalah 63,73%, sedangkan pada kedalaman 3 meter adalah 77,61%. Secara keseluruhan kondisi terumbu karang masih tergolong baik. Kelimpahan rata-rata ikan pada sisi Barat kedalaman 1 meter adalah 70 individu/125 m2, sedangkan pada kedalaman 3 meter adalah 232 individu/125 m2. Kelimpahan ikan sisi Timur kedalaman 1 dan 3 meter masing-masing adalah 49 dan 138 individu/125 m2. Hasil perhitungan indeks korelasi secara keseluruhan menghasilkan nilai 0,8415 dengan koefesien determinasi sebesar 0,7081. Hal ini menunjukkan bahwa pola hubungan persentase tutupan karang dengan kelimpahan ikan karang kuat (signifikan) dan positif (searah). Coral reef ecosystem is a wealth of marine resources that have an important role in supporting the life of various aquatic organisms. One of the organisms that has a living dependence on coral reefs is reef fish. This is because coral fish through a partial or complete life phase on the coral reef, so that coral reefs become a place to live, a place to find food, shelter and breeding ground. The study was conducted in May 2017, with the objective of knowing the percentage of live coral cover and fish abundance. And the correlation of percentage of coral cover with abundance of reef fish on West and East side of Menjangan Kecil Island depth of 1 and 3 meters. The method used is field observation method, with sampling method using line transect on coral data and visual census for fish data along 25m. The results of this study indicate that the average percentage of coral cover obtained at a depth of 1 meter west side is 73.39%, while at a depth of 3 meters is 85.97%. The percentage of coral cover at depth of 1 meter East side is 63,73%, while at depth 3 meter is 77,61%. Overall the condition of coral reefs is still quite good. The average abundance of fish on the west side of 1 meter depth is 70 individuals / 125 m2, while at 3 meters depth is 232 individuals / 125 m2. The abundance of fish on Eastern side, depth of 1 and 3 meters respectively were 49 and 138 individu / 125 m2. Result of calculation of correlation index as a whole yield value 0,8415 with coefficient of determination equal to 0,7081. This shows that the pattern of correlation of percentage of coral cover with abundance of reef fish is strong (significant) and positive (unidirectional).


2019 ◽  
Author(s):  
Miguel Barbosa ◽  
Neil Coupland ◽  
Clara Douglas ◽  
Ellen Harrison ◽  
Kelly M James ◽  
...  

Corals provide structure and food sources vital for the maintenance of coral reef fish diversity. However, coral reefs are currently under threat from climate change, which has led to the largest recorded loss of live coral. The loss of live coral, and corresponding shift in reef benthic composition, are predicted to impact the abundance and composition of coral reef fish species and communities. In this study, we investigate the effect of changes in reef benthic composition (eg. live coral, dead coral, algae), on the diversity and composition in an assemblage of butterflyfish species, in Faafu Atoll in the Maldives after the 2016 bleaching event. We show that differences in community composition of butterflyfish are associated to benthic structure, reflecting species feeding preferences. Interestingly, however, we also show that lower coral cover is not associated to lower abundance and species richness of butterflyfish. Our results suggest that maintenance of coral reef structure after a disturbance provides key microhabitats to accommodate non-corallivorous butterflyfish, thus maintaining abundance and species richness. Overall our study provides support for regulation of richness and abundance of coral reef fish assemblages to short term changes in coral reef benthic composition after disturbance via turnover in composition.


2016 ◽  
Vol 80 (4) ◽  
pp. 479 ◽  
Author(s):  
Aurora M. Ricart ◽  
Fabián A. Rodríguez-Zaragoza ◽  
Carlos González-Salas ◽  
Marco Ortiz ◽  
Amílcar L. Cupul-Magaña ◽  
...  

Clipperton Atoll, one of the most isolated coral reefs worldwide, is of great scientific interest due to its geomorphology and high levels of endemism. This study explored the reef fish assemblage structure of Clipperton Atoll and its relationship with live coral cover. Nine stations were sampled at three sites and three depths (6, 12 and 20 m) around the reef, measuring fish species richness and biomass and hermatypic coral cover (at genus level). We evaluated variation in species richness, biomass and diversity of fish assemblages among sites and depths, as well as the relationship between the entire fish assemblage composition and live coral cover. The results showed that species richness and biomass were similar among sites, but differed across depths, increasing with depth. In contrast, diversity differed among sites but not among depths. Multivariate analyses indicated that fish assemblage composition differed among sites and depths in relation to changes in cover of coral of the genera Pocillopora, Porites, Pavona and Leptoseris, which dominate at different depths. The results showed that fish species richness and diversity were low at Clipperton Atoll and that, in isolated coral reefs with a low habitat heterogeneity and low human disturbance, live coral cover has a significant influence on the spatial variation of the reef fish assemblages. This study highlights the importance of coral habitat structure in shaping coral reef fish assemblages.


2018 ◽  
Vol 10 (2) ◽  
pp. 76
Author(s):  
Apri Arisandi ◽  
Badrud Tamam ◽  
Achmad Fauzan

Abstrak Ekosistem terumbu karang merupakan bagian dari ekosistem laut yang penting, karena menjadi sumber kehidupan bagi biota laut.  Penelitian ini bertujuan untuk mengumpulkan data berupa persentase penutupan karang hidup, lifeform dan jumlah karang.  Kelimpahan ikan karang dan kondisi perairan kepulauan yang terdapat ekosistem terumbu karang bisa menjadi dasar untuk mendukung kesesuaian suatu kawasan menjadi objek ekowisata bahari.  Penelitian dilaksanakan pada bulan juli-Agustus dan dilakukan menggunakan metode Line Intercept Transect (LIT), sepanjang 50 meter sejajar garis pantai pada kedalaman 3 dan 10 meter. Persentase penutupan karang mengacu kepada lifeform dan data ikan karang diambil menggunakan metode pencacahan langsung (visual census).  Hasil penelitian menunjukkan bahwa persentase tutupan karang berada pada kisaran 60-73% yang artinya kondisi ekosistem terumbu karang di Pulau Kangean adalah baik, dan merupakan habitat yang nyaman bagi ikan-ikan karang seperti spesies Apogon sp., Chelmon sp., Chaetodon sp., Lethrinus sp., dan Cheilodipterus sp. AbstractCoral reef ecosystems are part of an important marine ecosystem because they are a source of life for marine biota. This study was aimed to collect data in the form of a percentage of live coral cover, lifeform and number of corals. The abundance of reef fish and the condition of island waters that have coral reef ecosystems can be the basis for supporting the suitability of an area to become an object of marine ecotourism. The study was conducted in July-August and was carried out using the Line Intercept Transect (LIT) method, along 50 meters parallel to the coastline at depths of 3 and 10 meters. The percentage of coral cover refers to the lifeform and data on reef fish are taken using the visual census method. The results showed that the percentage of coral cover was in the range of 60-73%, which means that the condition of the coral reef ecosystem in Kangean Island is good, and is a comfortable habitat for reef fish such as the species Apogon sp., Chelmon sp., Chaetodon sp., Lethrinus sp., and Cheilodipterus sp.


2019 ◽  
Author(s):  
Miguel Barbosa ◽  
Neil Coupland ◽  
Clara Douglas ◽  
Ellen Harrison ◽  
Kelly M James ◽  
...  

Corals provide structure and food sources vital for the maintenance of coral reef fish diversity. However, coral reefs are currently under threat from climate change, which has led to the largest recorded loss of live coral. The loss of live coral, and corresponding shift in reef benthic composition, are predicted to impact the abundance and composition of coral reef fish species and communities. In this study, we investigate the effect of changes in reef benthic composition (eg. live coral, dead coral, algae), on the diversity and composition in an assemblage of butterflyfish species, in Faafu Atoll in the Maldives after the 2016 bleaching event. We show that differences in community composition of butterflyfish are associated to benthic structure, reflecting species feeding preferences. Interestingly, however, we also show that lower coral cover is not associated to lower abundance and species richness of butterflyfish. Our results suggest that maintenance of coral reef structure after a disturbance provides key microhabitats to accommodate non-corallivorous butterflyfish, thus maintaining abundance and species richness. Overall our study provides support for regulation of richness and abundance of coral reef fish assemblages to short term changes in coral reef benthic composition after disturbance via turnover in composition.


2019 ◽  
Author(s):  
Miguel Barbosa ◽  
Neil Coupland ◽  
Clara Douglas ◽  
Ellen Harrison ◽  
Kelly M James ◽  
...  

Corals provide structure and food sources vital for the maintenance of coral reef fish diversity. However, coral reefs are currently under threat from climate change, which has led to the largest recorded loss of live coral. The loss of live coral, and corresponding shift in reef benthic composition, are predicted to impact the abundance and composition of coral reef fish species and communities. In this study, we investigate the effect of changes in reef benthic composition (eg. live coral, dead coral, algae), on the diversity and composition in an assemblage of butterflyfish species, in Faafu Atoll in the Maldives after the 2016 bleaching event. We show that differences in community composition of butterflyfish are associated to benthic structure, reflecting species feeding preferences. Interestingly, however, we also show that lower coral cover is not associated to lower abundance and species richness of butterflyfish. Our results suggest that maintenance of coral reef structure after a disturbance provides key microhabitats to accommodate non-corallivorous butterflyfish, thus maintaining abundance and species richness. Overall our study provides support for regulation of richness and abundance of coral reef fish assemblages to short term changes in coral reef benthic composition after disturbance via turnover in composition.


2018 ◽  
Vol 7 (3) ◽  
pp. 246-252
Author(s):  
Lillah Gustilah ◽  
Anhar Solichin ◽  
Pujiono Wahyu Purnomo

Pulau Cilik merupakan salah satu dari 27 Pulau yang membentuk kepulauan Karimunjawa, Jawa Tengah. Kondisi terumbu karang yang masih baik menjadikan Pulau Cilik sebagai salah satu objek wisata. Adanya kegiatan pariwisata dikhawatirkan dapat mengganggu kondisi ekosistem terumbu karang. Tujuan dari penelitian ini untuk mengetahui jenis dan perbedaan kelimpahan ikan antar kedalaman dan hubungan kerapatan bentuk karang dan kelimpahan ikan karang di berbagai tingkat kedalaman yang berbeda di Pulau Cilik Taman Nasional Karimunjawa, Jawa Tengah. Penelitian ini dilaksanakan pada bulan September 2016 di perairan Pulau Cilik Taman Nasional Karimunjawa, Jawa Tengah. Metode penelitian yang digunakan dalam penelitian bersifat deskriptif. Pengamatan dilakukan pada 4 stasiun yaitu barat, selatan, utara dan timur Pulau Cilik terdapat 2 titik kedalaman titik 1 3 m dan 10 m, masing-masing dilakukan pengulangan pengamatan 2 kali. Pada setiap titik dilakukan pengukuran parameter fisika dan kimia air, pengamatan kondisi bentuk karang dan kelimpahan ikan. Analisis data meliputi indeks keanekaragaman, keseragaman dan perhitungan persentase tutupan karang hidup, karang mati, pasir dan pecahan karang. Data yang telah diperoleh selanjutnya dianalisa statistik dengan uji t, yaitu membandingkan kelimpahan ikan karang antara kedalaman 3 m dan 10 m serta membandingkan perbedaan hubungan antara bentuk karang dan ikan karang. Hasil Bentuk karang yang terdapat di Pulau Cilik yaitu bentuk karang keras dan kelimpahan ikan karang yang mendominasi adalah jenis ikan Pomacentridae. Hubungan kerapatan terumbu karang dengan kelimpahan ikan karang terdapat hubungan positif dengan nilai koefisien korelasi (R) sebesar 0,6861 pada kedalaman 3 m dan 10 m, Persentase tutupan terumbu karang hidup termasuk kategori baik (>50%). Cilik Island is one of 27 island that form the Karimunjawa islands, Central Java. The condition of coral reefs are still outstanding to make Cilik Island as one of tourist destinations. The existence of tourism activities is worried to disrupt the condition of coral reef ecosystems. The aim of this research is to recognise the types and differences of fish abundance between depth and the relation of coral cover density and abundance of reef fish at different level of depth in Cilik Island Karimunjawa National Park, Central Java. This research was conducted in September 2016 in the waters of Pulau Cilik Karimunjawa National Park, Central Java. The research method used in the research is descriptive method. The observations were conducted on 4 stations, they are west, south, north and east of Cilik Island has 2 points depth point of 3m and 10m,each of observation was reapeted twice. At each point, It was conducted the measurement on physical and chemical parameters of water, observation of coral cover condition and fish abundance. Analysis data included index of diversity, uniformity and calculation of percentage of live coral cover, dead corals, sand and coral fragments. The obtained data were then analyzed statistically with t-test, by comparing the abundance of reef fish between 3 m and 10 m of depth and comparing the differences between coral cover and reef fish. The results of coral shape found in Pulau Cilik is the form of hard corals and the abundance of reef fish that dominate is Pomacentridae fish species. The correlation of coral reef density with abundance of reef fish has positive correlation with correlation coefficient value (R) 0,6861 at depth of 3 m and 10 m. The percentage of live coral cover is good category (> 50%). 


2020 ◽  
Vol 649 ◽  
pp. 125-140
Author(s):  
DS Goldsworthy ◽  
BJ Saunders ◽  
JRC Parker ◽  
ES Harvey

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.


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