Los Roques and Las Aves Archipelagos, Venezuela: A Marine Ecological and Conservation Reconnaissance of Two Little-Known Southeastern Caribbean Oceanic Archipelagos

The ocean covers about seventy percent of the planet. The ocean provides many economic activities that include fisheries, tourism, and marine transport. Two-thirds of the value of all natural services is in the world is provided by the ocean. Fisheries related activities alone support the livelihood of approximately 200 million people in the world. As an island Sri Lanka is heavily depend on the ocean for economic development and food security. The coastal zone contains 62% of the industries and 70% of infrastructure related to tourism. Sri Lanka has a coastline of about 1620 km. The continental shelf covers about 30,000 km2. It is relatively narrow, averaging 22.5 km, width and the mean depth is approximately 75 m. The exclusive economic zone is about 517,000 km2. The marine environment around the country is governed by the northeast and southwest monsoons. The tidal range is low; the maximum spring tide is less than 1 m. The country is endowed with highly productive marine ecosystems; mangroves, sea grass meadows and coral reefs. In addition there are many coastal wetlands including salt marshes. The majority of mangroves are associated with coastal lagoons and the sea grass meadows are in the Gulf of Mannar and the Palk Bay where the sea is relatively shallow and calm. Coral reefs occur around the island with the largest shallow-water coral banks in the Gulf of Mannar. There are 40 species of mangrove and mangrove associated plants, 15 species of sea grasses and 208 species of corals recorded for Sri Lanka. There may be more than 1500 species of marine fish in Sri Lanka’s marine waters. The charismatic marine mega fauna include 5 species of sea turtles and twenty eight species of marine mammals. Although some groups have been studied relatively well, there is a general lack of information on marine biodiversity, especially the marine invertebrates. Sri Lanka depends heavily on marine resources both in coastal and offshore areas. Fishing is main economic activity supporting nearly 1.25 million people. The coastal waters provide about 65% of the marine fish production. Extraction of hydrocarbons may become one of the most important economic activities in the future. The marine environment around the country is heavily influenced by human activities including unsustainable resource exploitation and the use of destructive fishing methods. It is widely accepted that the coastal waters have been overfished as the populations of many large fish species have been reduced drastically. Many land-based activities have contributed to high levels of pollution in the coastal environment. Poor garbage disposal, agricultural runoff and industrial and domestic waste have polluted several coastal lagoons, beaches and inshore waters. More recently Sri Lanka has experienced negative impacts of global warming and climate change. Coral reefs have indicated this rapid environmental change through extensive coral bleaching events. Sri Lanka lost much of its shallow water coral reefs in 1998 during the unprecedented coral bleaching event in the Indian Ocean. A similar bleaching event has occurred in 2016 where many shallow water corals have been affected. However, adaptive management is lacking in Sri Lanka. Although several marine protected areas and fisheries management areas have been established, there is little or no management of human activities in these declared areas. In general there is a lack of implementation of laws and regulations which result in the continuous degradation of the marine environment. Keywords: Marine environment, Coastal, Resources, Management

Exposure of coastal ecosystems to river plume spreading across a near-equatorial continental shelf

The structures of fish assemblages in twoThalassia testudinum beds in Guadeloupe, French West Indies, one adjacent to mangroves and the other adjacent to coral reefs, were compared between January 1983 and May 1984. The aim of the study was to compare the influences of mangroves and coral reefs on the utilization of seagrass beds by fishes through examination of species composition, catch rate, size of fishes and temporal changes. The two fish assemblages were similar in terms of the number of species they had in common (nearly 44% of the total number of species collected) and the great abundance of juveniles. They both comprised species that usually inhabit other habitats, i.e., estuaries, open waters or coral reefs. Estuary-associated species (e.g. Gerreidae) were the most abundant species in the seagrass bed near the mangroves, while small pelagic species (e.g. Clupeidae) were the most abundant species in the seagrass bed near the coral reefs. The seagrass bed near the mangroves was preferentially utilized as a nursery area by small juveniles of various species (e.g. Clupeidae, Sparidae, Gerreidae, and at least one coral reef species,Ocyurus chrysurus). The abundance of these species varied frequently, suggesting successive arrivals and departures of juveniles over time. The seagrass bed near the coral reefs was characteristically utilized by fishes that are more able to avoid predation, i.e., fishes that forage over seagrass beds at night and shelter in or near the coral reefs during the day (large juveniles of coral reef species and adults of schooling pelagic species, respectively). The constant migrations of these fishes between the coral reefs and seagrass beds explained the relative stability of the structure of the fish assemblage in the seagrass bed over time. Thus, the two seagrass beds were not equivalent habitats for fishes. The distinct ecological influences of the mangroves (as a nursery for small juveniles) and coral reefs (as a shelter for larger fishes) on the nearby seagrass beds was clearly reflected by the distinct utilizations of these seagrass beds by fishes.

Coral reefs and seagrass beds are often located adjacent to one another, but little is known about the degree to which their fish communities are interlinked. To determine whether coral reef fishes on the coral reef are interlinked with or segregated from fishes on adjacent seagrass beds, a 60 m coral reef-seagrass gradient was studied on the island of Zanzibar in the western Indian Ocean. Using underwater visual census, coral reef fishes were surveyed in 4 habitat zones: (1) a coral patch reef, (2) seagrass beds bordering the coral reef, (3) seagrass beds at a 30 m distance from the coral reef edge and (4) seagrass beds at a 60 m distance from the coral reef edge. Based on the den- sities of juveniles and adults in the 4 zones, the 48 species that were observed were classified into reef-associated species, seagrass-associated species, nursery species, generalists and rare species. Reef-associated species occurred almost exclusively on the coral reef and at the reef-seagrass edge, while seagrass-associated species occurred almost exclusively on the seagrass beds. Generalists and seagrass-associated species occurred in all 3 seagrass zones, but densities of generalists on seagrass beds decreased with increasing distance from the reef, whereas that of seagrass-associated species increased. Reef-associated and generalist species showed an edge effect, where densities on the sea- grass beds near the reef edge were higher than on the seagrass beds further away. Juvenile densities of nursery species on seagrass beds also increased with the distance from the reef, whereas their adults showed the highest densities on the coral reef, suggesting a possible ontogenetic shift from the seagrass beds to the reef. The results of the present study show that this seagrass-coral reef land- scape features habitat segregation between species and life stages and shows an edge effect, possibly driven by competition mechanisms between species or life stages.

There is a long-standing debate whether mangrove and seagrass habitats in the Indo- Pacific region function as nurseries for coral reef fishes. We studied the use of all major shallow-water habitat types by juvenile coral reef fish using visual census surveys at 4 islands along the Tanzanian coast (East Africa) and at the island of Grande Comoros (Comoros archipelago). We investigated the value of mangroves, seagrass beds, coral reefs, macroalgae and intertidal flats as a juvenile habitat for fish by studying density distribution patterns of juveniles and adults of 76 reef fish species in these habitats. We assessed (1) which part of the reef fish community used mangrove-seagrass habitats as juvenile or adult habitats, (2) whether adult fish densities and diversity on adjacent reefs were related to the presence of these shallow habitats, and (3) whether adults of species that use these habitats when juvenile were less abundant on coral reefs situated far away from these juvenile habitats. Sea- grass beds and coral reefs were the most important juvenile fish habitats. Ontogenetic migrations between seagrass beds and reef habitats possibly occur, since several species showed their highest juvenile densities on seagrass beds, whereas adults showed their highest densities on reefs adjacent to these seagrass beds. The presence of areas with seagrass beds positively influenced adult densi- ties of many reef fish species on adjacent coral reefs. Of the 36 fish species whose juveniles were observed in seagrass beds along the Tanzanian coast, 32 species were absent from or showed low densities on coral reefs of the island of Grande Comoros (lacking seagrass beds or mangroves). On reefs far from seagrass beds and mangroves along the Tanzanian coast, 25 of these 36 species were absent or showed low densities in comparison with reefs adjacent to these habitats.

We quantify the relative importance of multi‐scale drivers of reef fish assemblage structure on isolated coral reefs at the intersection of the Indian and Indo‐Pacific biogeographical provinces. Large (>30 cm), functionally‐important and commonly targeted species of fish, were surveyed on the outer reef crest/front at 38 coral reef sites spread across three oceanic coral reef systems (i.e. Christmas Island, Cocos (Keeling) Islands and the Rowley Shoals), in the tropical Indian Ocean (c. 1.126 x 106 km2). The effects of coral cover, exposure, fishing pressure, lagoon size and geographical context, on observed patterns of fish assemblage structure were modelled using Multivariate Regression Trees. Reef fish assemblages were clearly separated in space with geographical location explaining ~53 % of the observed variation. Lagoon size, within each isolated reef system was an equally effective proxy for explaining fish assemblage structure. Among local‐scale variables, ‘distance from port’, a proxy for the influence of fishing, explained 5.2% of total variation and separated the four most isolated reefs from Cocos (Keeling) Island, from reefs with closer boating access. Other factors were not significant. Major divisions in assemblage structure were driven by sister taxa that displayed little geographical overlap between reef systems and low abundances of several species on Christmas Island corresponding to small lagoon habitats. Exclusion of geographical context from the analysis resulted in local processes explaining 47.3% of the variation, highlighting the importance of controlling for spatial correlation to understand the drivers of fish assemblage structure. Our results suggest reef fish assemblage structure on remote coral reef systems in the tropical eastern Indian Ocean reflects a biogeographical legacy of isolation between Indian and Pacific fish faunas and geomorphological variation within the region, more than local fishing pressure or reef condition. Our findings re‐emphasise the importance that historical processes play in structuring contemporary biotic communities.

Seagrass meadows are important for carbon storage, this carbon is known as “blue carbon” and represents a vital ecosystem service. Recently there has been growing interest in connectivity between ecosystems and the potential for connected ecosystems to facilitative ecosystem services. Tropical seagrass meadows are connected to coral reefs, as the reef barrier dissipates waves, which facilitates sediment accumulation and avoid erosion and export. Therefore, coral reefs might enhance the seagrass meadows capacity as a blue carbon sink. We tested this hypothesis through an assessment of blue carbon across a gradient of connected seagrass meadow and coral reef sites. We assessed attributes of seagrass meadows along a transect in addition to classifying the sites as exposed and sheltered. Classification of sites was completed through analyzing wave crest density in photographs and using granulometric evenness index. Organic carbon and organic matter were measured in sediment core samples and within seagrass living biomass (both above and below ground). Lastly, we measured changes in above and below ground traits of seagrass plants across the same sites. Gaps in the reef barrier were linked to high wave disturbance and exposed conditions, whilst barrier continuity to low wave disturbance and sheltered conditions. Organic carbon in sediments was 144 Mg ha-1 in the most sheltered (with reef barrier) and 91 Mg ha-1 in the most exposed (without reef barrier) meadows. Sheltered conditions also showed a redistribution of seagrass biomass to a greater quantity of roots compared to rhizomes. Whilst in exposed conditions the opposite occurred, which could be due to increased rhizome biomass have to enhanced anchorage or greater nutrient availability. This study found that coral reefs facilitate blue carbon potential in seagrass meadows indicating that coral reefs support this important ecosystem service. Also, results suggest that loss of coral reef structure due to bleaching and other stressors will likely result in a reduction of the blue carbon storage capacity of adjacent seagrass meadow. Further research should investigate how combined global and regional stresses may impact on the potential for coral reefs to buffer seagrass meadows, and how these stresses affect the functional traits of seagrass plants.

Chienhsun Chen and Hui-Ling Lin (2017) Coral reefs in the South China Sea are threatened by environmental changes and anthropogenic disruptions. Foraminifera, a group of unicellular shelled protists, has been considered a reliable indicator of water quality and reef health. However, this indicator has not yet been used to study coral reefs in the South China Sea. In this study of foraminifera in the lagoon of Dongsha Atoll, both the assemblage diversity and the functional group composition were investigated. The FORAM index (FI), a numerical indicator based on functional group composition, was used to evaluate the condition of the coral reef of the Atoll lagoon. A typical assumption is that FI = 4 is the minimum index value corresponding to a suitable environment for the growth of calcifying organisms. Environments with FI values between 2 and 4 are unsuitable to marginal for recovery of coral communities after a mortality event. Data were recorded regarding a total of 287 foraminiferal species. Approximately 68% of the tests belonged to the porcelaneous taxa; the Quinqueloculina, Triloculina, and Pseudomassilina species were well represented. Hyaline foraminifera were less abundant than porcelaneous foraminifera; the agglutinated foraminifera were the least abundant. Multivariate analyses revealed four clustering groups. The functional groups were classified according to FI's definition; the heterotrophic group was the most abundant, accounting for 82% of foraminiferal abundance. The symbiont-bearing group was the second most abundant, with a relative abundance of 12%; and the stress-tolerant group was the least abundant. Two samples had FI values slightly higher than 4; Amphisorus and Calcarina were dominant, but the other symbiont-bearing foraminifera had lower values. These high FI values can be associated with seagrass meadows or relict shells in an altered environment. Eighty percent of the sediment samples had FI values lower than 4, indicating that most of the benthic habitats in the Dongsha lagoon are not suitable for coral growth and reef recovery. The present findings provide an alternative evaluation method based on foraminiferal assemblages for future studies on the environmental changes of coral reefs.

Phyllum of echinoderms has a large role on the ecosystems of coral reefs and seagrass beds, especially their various roles in foodweb, which are herbivorous covering, carnivorous, or as detritus eaters. One of the echinoderms which is always found in the coralreefs region and seagrass beds is the echinoidea. Echinoidea mostly inhabits coral reef ecosystem and seagrass beds and found onhard substrates, especially in seagrass beds substrates that consist of mixtures of sand and crushed corals. The purpose of thisresearch was to know the difference in the echinoidea abundances of coral reef ecosystem and seagrass beds in Pancuran Belakang,Karimunjawa, Jepara in the month of May 2014. Research methodology that was used is a method of direct observation that is bymeans of observing the species of echinoidea found in coral reef ecosystems and seagrass beds and water quality conditions assupporting data. The research results showed that the cover of coral reefs and seagrass beds in Pancuran Belakang Karimunjawa inthe category of good which are of 55.29 % on coarl reef and 61.94 % seagrass. The echinoidea that was found in reefs and seagrassbeds is Diadema setosum (123;36 ind (150 m)-2), Diadema antilarum (63;18 ind(150 m)-2), Echinothrix calamaris (34;22 ind (150m)-2), Mespilia globulesa (12;0 ind(150 m)-2), and Echinometra mathaei (14;0 ind(150 m)-2), The independent t test with SPSSsignificant value of 5 % t table = 2.776 > t calculated = -2.319. Therefore, Ho was accepted that there is a significant difference ofthe echinoidea on the coral reefs and seagrass beds.Keywords : Echinoideas; Coral Reef; Seagrass, Pancuran Belakang and Karimunjawa

Global decline in capacity of coral reefs to provide ecosystem services

Large conservation opportunities exist in >90% of tropic-subtropic coastal habitats adjacent to cities

Ecology of rays on tropical coral reefs

Post-settlement Life Cycle Migration Patterns and Habitat Preference of Coral Reef Fish that use Seagrass and Mangrove Habitats as Nurseries

Tropical marine habitats are often energetically linked through feeding migrations by fish. A widely accepted assumption is that species of Haemulidae (grunts) undertake nocturnal feed- ing migrations from coral reefs to seagrass beds. This has been based on studies investigating migra- tions between small patch reefs and surrounding seagrass beds located in lagoons. Due to the size and location of these patch reefs, we argue that this does not represent migration from coral reef to seagrass ecosystems, and a literature search shows limited proof for such migration. We hypothesised that the spatial arrangement of these habitats in the seascape may have profound effects on the degree to which such migrations occur. Haemulon flavolineatum caught from seagrass beds located in semi-enclosed embayments, and thus isolated to a high degree from adjacent reefs, showed a diet and stable isotope signature of muscle tissue that differed from those collected from the coral reef. In contrast, fishes from open seagrass systems without restricted access from the reef showed the same stable isotope signature as those collected from the coral reef, suggesting feeding from the same habitat, viz. the seagrass beds. Additional visual census data showed that semi-enclosed seagrass beds did not have elevated densities of large-sized fish at night, which would be expected if large individuals from the reef migrated to the seagrass beds to feed. The data thus show that interlinkages between coastal ecosystems, such as coral reefs and seagrass beds, by fishes may strongly depend on the spatial arrangement of habitats within the seascape.

Many coral reef fish exhibit habitat partitioning throughout their lifetimes. Such patterns are evident in the Caribbean where research has been predominantly conducted in the Eastern region. This work addressed the paucity of data regarding Honduran reef fish distribution in three habitat types (seagrass, mangroves, and coral reefs), by surveying fish on the islands of Utila and Cayos Cochinos off the coast of Honduras (part of the Mesoamerican barrier reef). During July 2nd - Aug 27th 2007 and June 22nd - Aug 17th, 2008, visual surveys (SCUBA and snorkel) were performed in belt transects in different areas: eleven coral reef, six seagrass beds, and six mangroves sites. Juvenile densities and total habitat surface area were used to calculate nursery value of seagrass and mangroves. A total of 113 fish species from 32 families were found during underwater surveys. Multi-dimensional analyses revealed distinct clusters of fish communities in each habitat type by separating fish associated with seagrass beds, mangroves, and coral reefs. Coral reefs showed the highest mean fish species richness and were dominated by adult fish, while juvenile fish characterized seagrass beds and mangrove sites. Habitat use differed widely at the fish species level. Scarus iseri (Striped Parrotfish), the most abundant fish in this study, were found in all three habitat types, while Lutjanus apodus (Schoolmaster Snapper) juveniles were located primarily in mangroves before migrating to coral reefs. Many species used seagrass beds and mangroves as nurseries; however, the nursery value could not be generalized at the family level. Furthermore, for some fish species, nursery value varied between islands and sites. Our results suggest that connectivity of seagrass, mangrove, and coral reef sites at a species and site levels, should be taken into consideration when implementing policy and conservation practices.