scholarly journals Sea Urchins Play an Increasingly Important Role for Coral Resilience Across Reefs in Taiwan

2020 ◽  
Vol 7 ◽  
Author(s):  
Viet D. H. Dang ◽  
Pak-Yin Cheung ◽  
Chia-Ling Fong ◽  
Aziz J. Mulla ◽  
Jia-Ho Shiu ◽  
...  
Keyword(s):  
Coral Reefs ◽  
Sea Urchin ◽  
Sea Urchins ◽  
Coral Cover ◽  
Management Strategies ◽  
Key Factors ◽  
Juvenile Coral ◽  
Multivariable Regression ◽  
Coral Recovery ◽  
Multivariable Regression Models

Herbivores are an important functional group that control algae, create new space, and promote recruitment for coral recovery. However, on many coral reefs, overfishing has greatly decreased the density of herbivores, especially fishes and gastropods, impairing coral resilience. On such overfished reefs, remnant herbivores that are not target species of local fisheries, e.g., sea urchins, are expected to play an increasingly important role, yet few studies, except for those in the Caribbean and Kenya have examined non-fish herbivores in relation to coral resilience. Here, we conducted field surveys at 30 sites along three coral reefs in Taiwan between 2016 and 2017, to examine the relative importance of six key factors for coral resilience: herbivore abundance (fishes, gastropods, sea urchins), coral cover, macroalgal cover, habitat complexity, water depth, and wave exposure. The density of juvenile coral was used as a proxy of coral resilience. Diadematid sea urchins (Echinothrix spp. and Diadema spp.) dominated most sites (19 of 30 sites) and multivariable regression models showed sea urchin density as the best positive predictor of coral juvenile density. The results elucidated the increasing role diadematid sea urchins play as remnant herbivores on overfished coral reefs in Taiwan. Given that overfishing is a widespread issue, this phenomenon may be occurring globally. More studies are needed to examine the role of remnant, but often ignored, sea urchin herbivory on coral resilience. Reef managers should consider monitoring locally remnant herbivores and incorporating them into management strategies.

scholarly journals ASPEK REPRODUKSI BULU BABI (Sea Urchin) DI PERAIRAN PULAU MENJANGAN KECIL, KEPULAUAN KARIMUNJAWA, JEPARA (Aspects Reproduction of Sea Urchin in the Waters of Menjangan Kecil Island, Karimunjawa Islands, Jepara)

2018 ◽  
Vol 6 (4) ◽  
pp. 564-571
Author(s):  
Indrie Hapsari Puspitaningtyas ◽  
Siti Rudiyanti ◽  
Bambang Sulardiono
Keyword(s):  
Coral Reefs ◽  
Sea Urchin ◽  
Sea Urchins ◽  
Diversity Index ◽  
Coral Cover ◽  
Sampling Site ◽  
Gonad Maturity ◽  
Hard Coral Cover ◽  
Two Stages ◽  
Diadema Setosum

Gugusan terumbu karang yang terdapat di Kepulauan Karimunjawa termasuk ke dalam gugusan terumbu karang tepi dengan kisaran penutupan karang keras antara 6,7% - 68,9% dan indeks keragaman berkisar antara 0,43 - 0,91. Salah satu biota yang berasosiasi di ekosistem terumbu karang adalah bulu babi, yang merupakan biota filum echinodermata yang tersebar dari daerah intertidal dangkal hingga ke laut dalam. Gonad bulu babi di pasaran dikenal sebagai uni atau roe merupakan makanan populer dan salah satu komoditi utama di beberapa negara seperti Amerika Serikat, Kanada, Chili, Rusia, Prancis, Barbados dan Jepang. Penangkapan hingga overfishing menjadi masalah utama di berbagai negara, yang  akan mengakibatkan penurunan jumlah populasi bulu babi di perairan. Penelitian ini dilakukan di Pulau Menjangan Kecil, Karimunjawa pada bulan Mei 2017. Tujuan dari penelitian ini adalah mengetahui aspek reproduksi bulu babi melalui nilai IKG, nilai TKG, dan Fekunditas Bulu Babi di Pulau Menjangan Kecil. Penelitian ini dilakukan dalam dua tahap yaitu, tahap sampling lapangan yang terdiri dari pengambilan sampel bulu babi, dengan metode acak menggunakan kuadran transek, dan pengukuran kualitas perairan. Tahap analisis laboratorium yang terdiri dari analisis Indeks Kematangan Gonad, Tingkat Kematangan Gonad, dan Fekunditas. Penelitian ini ada dua spesies yang ditemukan di lokasi sampling yaitu Diadema setosum dan Echinothrix calamaris. Hasil yang diperoleh untuk bulu babi jenis Diadema setosum nilai IKG berkisar antara 1,66% - 4,26% dan fekunditas berkisar antara 641 butir – 1.087 butir dan bulu babi jenis Echinothrix calamaris nilai IKG berkisar antara 5,32% - 7,54% dan fekunditas berkisar antara 1.159 butir – 2.192 butir, sedangkan nilai TKG kedua jenis bulu babi berada pada fase 5 (lima) yaitu tahap memijah.  The coral reefs found in the Karimunjawa Islands are included in the cluster of coral reefs with hard coral cover ranges between 6.7% - 68.9% and the diversity index ranges from 0.43 to 0.91. One of the associated biota in the coral reef ecosystem is the sea urchin, which is an echinodermata physiological biota scattered from the shallow intertidal region to the deep sea. The sea urchin gonad on the market is known as uni or roe is a popular food and one of the main commodities in some countries such as USA, Canada, Chile, Russia, France, Barbados and Japan. Overfishing is a major problem in many countries, which will lead to a decrease in the number of sea urchin populations. This research was conducted in Menjangan Kecil Island, Karimunjawa in May 2017. The purpose of this research is to know the reproductive aspect of the sea urchin through IKG value, TKG value, and Fecundity of sea urchin on Menjangan Kecil Island. This research was conducted in two stages, field sampling stage consisting of sampling of sea urchins, by random method using transect quadrant, and measurement of water quality. Phase of laboratory analysis consisting of Gonad Maturity Index analysis, Gonad Maturity Level, and Fecundity. The study used only two species found at the sampling site is Diadema setosum and Echinothrix calamaris. The results obtained for Diadema setosum type IKG ranged from 1.66% - 4.26% and fecundity ranged from 641 grains - 1.087 grains and Echinothrix calamaris type IKG in the range of 5.32% - 7.54% and fecundity ranges from 1,159 grains - 2,192 grains, while the TKG value of both types of sea urchins is in phase 5 (five) or spawning phase.

scholarly journals POPULATION CONDITIONS OF ECHINOIDEA AND CORAL REEF COVERS IN PONCAN GODANG ISLAND, SIBOLGA, NORTH SUMATERA

2021 ◽  
Vol 4 (2) ◽  
pp. 112-116
Author(s):  
Nainul Adni ◽  
Aras Mulyadi ◽  
Thamrin Thamrin
Keyword(s):  
Coral Reef ◽  
Coral Reefs ◽  
Sea Urchin ◽  
Sea Urchins ◽  
Coral Cover ◽  
Coral Reef Ecosystem ◽  
Transect Line ◽  
Coral Reef Ecosystems ◽  
North Sumatra ◽  
Line Intercept

Poncan Godang Island is included in the appropriate category based on the suitability of land for the Sibolga tourist area, with the presence of tourism activities that can also affect the amount of biodiversity in it. Considering the importance of coral reefs for biodiversity and sea urchins which also have a role in coral reef ecosystems, it is necessary to conduct research on the condition of sea urchins population and the percentage of coral reefs on Poncan Godang Island. Sea urchin and coral reef data were collected using the Line Intercept Transect (LIT) method by monitoring directly on the transect line along 50 meters. The results obtained indicate that the population of sea urchins in the waters of Poncan Godang Island, North Sumatra can be described, that sea urchins do not affect the coral reef ecosystem because at stations 1 and 5 there is no sea urchin and the percentage of coral cover is classified as bad, but at station 3 there are 32 individuals with coral reef cover conditions, while at stations with The percentage of good coral cover is that at station 4 there are only 25 individuals, as well as at station 2 where the percentage of coral cover is higher than station 3 and there are no sea urchins

scholarly journals Hubungan Kepadatan Bulu Babi (Echinoidea) dan Tutupan Terumbu Karang pada Kawasan Intertidal Pantai Sanur

2017 ◽  
Vol 3 (2) ◽  
pp. 134
Author(s):  
Tiara Permata Sari ◽  
Abd. Rahman As-syakur ◽  
Yulianto Suteja ◽  
Dwi Budi Wiyanto
Keyword(s):  
Coral Reef ◽  
Coral Reefs ◽  
Sea Urchins ◽  
Coral Cover ◽  
Intertidal Area ◽  
Positive Direction ◽  
Community Activities ◽  
Cruise Tourism ◽  
The Many ◽  
The Relationship

Marine intertidal region is an area that is affected by the mainland. One of the ecosystems found in the intertidal area is the coral reef ecosystem. Urchin is one that lives on these ecosystems. Sanur Beach area has coral reefs and the intertidal zone is quite extensive. The many activities and cruise tourism in Sanur Beach will indirectly affect the life of coral reefs and associated animal in it in this case urchins. The purpose of this study was to determine the relationship density of sea urchins and coral reefs cover percentage in the intertidal area on Sanur Beach. Research done during low tide. Coral reef data collection method and the density of sea urchins using 5x5m quadratic transects were analyzed using Pear Person bivariate correlations. Urchin densities ranging between 0-2.04 ind/m2. The percentage cover coral reefs ranged from 0.1- 17.9%. High and low density of sea urchins and the percentage of coral reefs affected allegedly incompatibility place their lives and because of pressure from community activities in Sanur. The density of sea urchins and the percentage of coral cover has a significant relationship with a strong degree of correlation is 0.79. Positive direction on that relationship means that the higher percentage of coral reefs, the higher density of sea urchins. This assume in which they live almost the same that is in need of a hard substrate and urchins use of coral reefs as a shelter.

scholarly journals Investigating sea urchin densities critical to macroalgal control on degraded coral reefs

2021 ◽  
pp. 1-6
Author(s):  
Jan-Claas Dajka ◽  
Victoria Beasley ◽  
Gilberte Gendron ◽  
Nicholas AJ Graham
Keyword(s):  
Coral Reefs ◽  
Sea Urchin ◽  
Sea Urchins ◽  
Patch Reef ◽  
Western Indian Ocean ◽  
Macroalgal Cover ◽  
Current Densities ◽  
Tropical Sea ◽  
Density Treatment ◽  
Modelling Approach

Summary There is an assumption that tropical sea urchins are macroalgal grazers with the ability to control macroalgal expansion on degraded coral reefs. We surveyed abundances of Echinothrix calamaris, an urchin species common in the western Indian Ocean on 21 reefs of the inner Seychelles and predicted their density using habitat predictors in a modelling approach. Urchin densities were greatest on patch reef habitat types and declined with increasing macroalgal cover. Next, we experimentally investigated the macroalgae-urchin relationship by penning two sea urchin densities on macroalgal fields. Over six weeks, the highest density treatment (4.44 urchins m−2) cleared 13% of macroalgal cover. This moderate impact leads us to conclude that controlling macroalgal expansion is not likely to be one of the main functions of E. calamaris in the inner Seychelles given the current densities we found in our surveys (mean: 0.02 urchins m−2, maximum: 0.16 urchins m−2).

MONITORING CORAL RECOVERY AT NEARSHORE CORAL REEFS IN PHANGNGA PROVINCE, THE ANDAMAN SEA FOLLOWING THE 2010 CORAL BLEACHING EVENT

2017 ◽  
Author(s):  
Makamas Sutthacheep ◽  
Makamas Sutthacheep ◽  
Thamasak Yeemin ◽  
Thamasak Yeemin ◽  
Sittiporn Pengsakun ◽  
...  
Keyword(s):  
Coral Reef ◽  
Coral Reefs ◽  
Coral Bleaching ◽  
Coral Cover ◽  
Global Climate ◽  
Andaman Sea ◽  
Live Coral ◽  
Bleaching Event ◽  
Sea Star ◽  
Coral Recovery

Mass bleaching and subsequent mortality of scleractinian corals in response to elevated seawater temperatures has been considered as one of the most impacts of global climate change. Three extensive coral bleaching events in the Andaman Sea were reported, in the years 1991, 1995 and 2010. Studies on survival of coral colonies, coral recruitment and community structure of coral reef associated macrofauna would predict the trends for coral recovery from the impacts of coral bleaching events. The present study aimed to examine the status of coral communities, density of coral recruits and coral reef associated macrofauna at nearshore coral reefs in Phangnga Province, the Andaman Sea following the 2010 coral bleaching event. The dead coral cover was high (>50%) while the live coral cover was in the range of 13-21%. There was high diversity of coral recruits on natural substrates. The average densities of macrobenthic fauna varied from 1.9 to 2.6 individuals.m-2, with significant differences among study sites. The dominant macrobenthic species were a soft coral (Lobophytum sp.), a sea star (Linckia laevigata) and a sea urchin (Echinostrephus molaris). Coral recovery at these coral reefs would be possible but local anthropogenic stressors must be overwhelmingly reduced in order to enhance coral reef resilience. The long-term monitoring programs in the Andaman Sea are required for decision makers to support their adaptive management approaches.

scholarly journals Sea urchins, parrotfish and coral reefs in Grand Cayman, BWI: exemplar or outlier?

2020 ◽  
Author(s):  
elizabeth sherman
Keyword(s):  
Coral Reefs ◽  
Marine Protected Area ◽  
Sea Urchins ◽  
Coral Cover ◽  
Global Climate ◽  
Structural Complexity ◽  
Proximate Cause ◽  
Grand Cayman ◽  
The Face ◽  
Caribbean Coral Reefs

The change in state of Caribbean coral reefs over the last 40 years has been characterized by phase shifts from scleractinian coral cover to macroalgal cover, the loss of structural complexity and a decline in biodiversity. Not only do scientists want to understand these changes, but also predict the future of coral reefs and their capacity for resilience. In particular, the loss of herbivory, due to declines in parrotfish and the sea urchin Diadema antillarum, has been implicated in many studies as a proximate cause of the coral to macroalgal phase shift. However, reports of the particular role of these putative herbivores have varied, with some studies claiming a causal role for parrotfish, others for Diadema and still others suggesting no such relationships. Often these studies just examined one response measure of coral reef biodiversity. In this paper, I report the relationship between parrotfish and Diadema to many metrics of reef organization surveyed simultaneously in the same transects in reefs outside and within the Marine Protected Area (MPA) of Grand Cayman, an island that has been affected by increasing tourism over the last 30 years. The magnitudes of the various measures of reef diversity reported here are consistent with those reported elsewhere. The relationships among those measures are consistent with those reported in some prior studies and inconsistent with others, reflecting the variation in responses documented in prior studies. The presence of sea urchins was associated with survey sites having higher levels of coral cover, lower levels of macroalgae cover, and lower densities of parrotfish than survey sites without sea urchins. Moreover, parrotfish abundance was associated with a decrease in coral cover and little relationship to macroalgae cover. Neither coral cover nor macroalgae cover was different in sites within the MPA compared to sites outside the MPA. I argue that the combination of site-specific local stressors and their interaction with global stressors makes it unlikely that any one island or even regional reef system could serve as an exemplar for Caribbean-wide reef degradation. Moreover, it is difficult to assess the potential for reef resilience in the face of the ongoing assaults from increasing tourism pressures and global climate change.

scholarly journals Correlation between Coral Reef Condition and the Diversity and Abundance of Fishes and Sea Urchins on an East African Coral Reef

Oceans ◽  
2022 ◽  
Vol 3 (1) ◽  
pp. 1-14
Author(s):  
Pia Ditzel ◽  
Sebastian König ◽  
Peter Musembi ◽  
Marcell K. Peters
Keyword(s):  
Coral Reef ◽  
Coral Reefs ◽  
Sea Urchins ◽  
Coral Cover ◽  
Fish Diversity ◽  
East African ◽  
Fish Family ◽  
The Relationship ◽  
Gazi Bay ◽  
Reef Condition

Coral reefs are one of the most diverse marine ecosystems, providing numerous ecosystem services. This present study investigated the relationship between coral reef condition and the diversity and abundance of fishes, on a heavily fished East African coral reef at Gazi Bay, Kenya. Underwater visual censuses were conducted on thirty 50 × 5 m belt transects to assess the abundance and diversity of fishes. In parallel, a 25-m length of each of the same transects was recorded with photo-quadrats to assess coral community structure and benthic characteristics. For statistical analyses, multi-model inference based on the Akaike Information Criterion was used to evaluate the support for potential predictor variables of coral reef and fish diversity. We found that coral genus richness was negatively correlated with the abundance of macroalgae, whereas coral cover was positively correlated with both the abundance of herbivorous invertebrates (sea urchins) and with fish family richness. Similarly, fish family richness appeared mainly correlated with coral cover and invertebrate abundance, although no correlates of fish abundance could be identified. Coral and fish diversity were very low, but it appears that, contrary to some locations on the same coast, sea urchin abundance was not high enough to be having a negative influence on coral and fish assemblages. Due to increasing threats to coral reefs, it is important to understand the relationship among the components of the coral reef ecosystem on overfished reefs such as that at Gazi Bay.

MONITORING CORAL RECOVERY AT NEARSHORE CORAL REEFS IN PHANGNGA PROVINCE, THE ANDAMAN SEA FOLLOWING THE 2010 CORAL BLEACHING EVENT

2017 ◽  
Author(s):  
Makamas Sutthacheep ◽  
Makamas Sutthacheep ◽  
Thamasak Yeemin ◽  
Thamasak Yeemin ◽  
Sittiporn Pengsakun ◽  
...  
Keyword(s):  
Coral Reef ◽  
Coral Reefs ◽  
Coral Bleaching ◽  
Coral Cover ◽  
Global Climate ◽  
Andaman Sea ◽  
Live Coral ◽  
Bleaching Event ◽  
Sea Star ◽  
Coral Recovery

Mass bleaching and subsequent mortality of scleractinian corals in response to elevated seawater temperatures has been considered as one of the most impacts of global climate change. Three extensive coral bleaching events in the Andaman Sea were reported, in the years 1991, 1995 and 2010. Studies on survival of coral colonies, coral recruitment and community structure of coral reef associated macrofauna would predict the trends for coral recovery from the impacts of coral bleaching events. The present study aimed to examine the status of coral communities, density of coral recruits and coral reef associated macrofauna at nearshore coral reefs in Phangnga Province, the Andaman Sea following the 2010 coral bleaching event. The dead coral cover was high (>50%) while the live coral cover was in the range of 13-21%. There was high diversity of coral recruits on natural substrates. The average densities of macrobenthic fauna varied from 1.9 to 2.6 individuals.m-2, with significant differences among study sites. The dominant macrobenthic species were a soft coral (Lobophytum sp.), a sea star (Linckia laevigata) and a sea urchin (Echinostrephus molaris). Coral recovery at these coral reefs would be possible but local anthropogenic stressors must be overwhelmingly reduced in order to enhance coral reef resilience. The long-term monitoring programs in the Andaman Sea are required for decision makers to support their adaptive management approaches.

scholarly journals Drivers of recovery and reassembly of coral reef communities

2019 ◽  
Vol 286 (1897) ◽  
pp. 20182908 ◽  
Author(s):  
Marine Gouezo ◽  
Yimnang Golbuu ◽  
Katharina Fabricius ◽  
Dawnette Olsudong ◽  
Geory Mereb ◽  
...  
Keyword(s):  
Coral Reefs ◽  
Structural Equation ◽  
Time Frame ◽  
Ecological Data ◽  
Community Recovery ◽  
Positive Effects ◽  
Juvenile Coral ◽  
Coral Recovery ◽  
Coral Morphology

Understanding processes that drive community recovery are needed to predict ecosystem trajectories and manage for impacts under increasing global threats. Yet, the quantification of community recovery in coral reefs has been challenging owing to a paucity of long-term ecological data and high frequency of disturbances. Here we investigate community re-assembly and the bio-physical drivers that determine the capacity of coral reefs to recover following the 1998 bleaching event, using long-term monitoring data across four habitats in Palau. Our study documents that the time needed for coral reefs to recover from bleaching disturbance to coral-dominated state in disturbance-free regimes is at least 9–12 years. Importantly, we show that reefs in two habitats achieve relative stability to a climax community state within that time frame. We then investigated the direct and indirect effects of drivers on the rate of recovery of four dominant coral groups using a structural equation modelling approach. While the rates of recovery differed among coral groups, we found that larval connectivity and juvenile coral density were prominent drivers of recovery for fast growing Acropora but not for the other three groups. Competitive algae and parrotfish had negative and positive effects on coral recovery in general, whereas wave exposure had variable effects related to coral morphology. Overall, the time needed for community re-assembly is habitat specific and drivers of recovery are taxa specific, considerations that require incorporation into planning for ecosystem management under climate change.

Serviços ecossistêmicos prestados por recifes de coral nas ilhas de Tinharé e Boipeba, Baixo Sul da Bahia, Brasil

2018 ◽  
Author(s):  
Carla Isobel Elliff
Keyword(s):  
Ecosystem Services ◽  
Coral Reefs ◽  
Current Model ◽  
Management Strategies ◽  
Environmental Indicators ◽  
Management Actions ◽  
Shoreline Protection ◽  
Fringing Reefs ◽  
Integrated Valuation ◽  
Reef Decline

Coral reefs provide important ecosystem services to coastal communities. The Archipelago of Tinhar?e andBoipeba, Bahia, Brazil, are mostly surrounded by fringing reefs, which have undergone several chronichuman impacts. The objective of the present study was to apply an ecosystem-based approach byanalyzing the ecosystem services provided by the coral reefs of the Archipelago of Tinhar?e and Boipeba inorder to support management actions and serve as a tool for coastal management. Ecosystem serviceswere assessed through the observation of environmental indicators of their occurrence and by using asuite of models from the Integrated Valuation of Environmental Services and Tradeoffs (InVEST) softwarecombined with data from the Atlantic and Gulf Rapid Reef Assessment (AGRRA) protocol database. Theservices of greatest occurrence were food provision, habitat maintenance, shoreline protection andrecreation. While the main stressful factors were tourism activities, the absence of a sewage system andfisheries. The coral reefs presented potential for shoreline protection along 50.5% of the islands. Moreover,46.8% of the shoreline would present moderate to high vulnerability in case of coral reef disappearance.The coincidence of areas with high risk of loss in the capacity to provide services and highvulnerability in the scenario of absence of reefs is concerning. Thus, the current model for tourism usedin the area should be altered, as should new management strategies be implemented, which can bringbenefits and avoid reef decline.

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