scholarly journals Ecoregional and temporal dynamics of dugong habitat use in a complex coral reef lagoon ecosystem

2022 ◽  
Vol 12 (1) ◽  
Author(s):  
Solène Derville ◽  
Christophe Cleguer ◽  
Claire Garrigue

AbstractMobile marine species display complex and nonstationary habitat use patterns that require understanding to design effective management measures. In this study, the spatio-temporal habitat use dynamics of the vulnerable dugong (Dugong dugon) were modelled from 16 satellite-tagged individuals in the coral reef lagoonal ecosystems of New Caledonia, South Pacific. Dugong residence time was calculated along the interpolated tracks (9371 hourly positions) to estimate intensity of use in three contrasting ecoregions, previously identified through hierarchical clustering of lagoon topographic characteristics. Across ecoregions, differences were identified in dugong spatial intensity of use of shallow waters, deeper lagoon waters and the fore-reef shelf outside the barrier reef. Maps of dugong intensity of use were predicted from these ecological relationships and validated with spatial density estimates derived from aerial surveys conducted for population assessment. While high correlation was found between the two datasets, our study extended the spatial patterns of dugong distribution obtained from aerial surveys across the diel cycle, especially in shallow waters preferentially used by dugongs at night/dusk during high tide. This study has important implications for dugong conservation and illustrates the potential benefits of satellite tracking and dynamic habitat use modelling to inform spatial management of elusive and mobile marine mammals.

2017 ◽  
Vol 98 (5) ◽  
pp. 1109-1118
Author(s):  
Els Vermeulen

Very little information is available on bottlenose dolphin (Tursiops truncatus) habitat use in the South-western Atlantic. It is, however, essential in understanding their ecology and to improve conservation management. In this study, habitat use of bottlenose dolphins was examined in Bahía San Antonio, an area frequented by the species. Given the large tidal amplitude and extended intertidal zone in this bay, special focus was given to the intertidal vs subtidal habitat use patterns. Bottlenose dolphins were observed in only half of the surveyed area, with on average 1 dolphin group encountered per 100 km surveyed. All dolphin groups were seen in shallow waters <10 m deep. GLM analyses showed that especially during high tide, depth had an important effect on the dolphin encounter rate, with most dolphin groups encountered in the intertidal zone. While in the intertidal zone, most dolphin groups were observed to be engaged in surface feeding activities. The presented data indicate dolphins remained in shallow waters, and moved to the intertidal zone during high tide where they appear to find feeding opportunities. This information is believed to be of high value in understanding this population's ecological needs, and essential when aiming to improve marine conservation efforts at times of increased anthropogenic pressures in the area.


2021 ◽  
Vol 11 (2) ◽  
pp. 580
Author(s):  
Camilla Roveta ◽  
Anna Annibaldi ◽  
Afghan Afghan ◽  
Barbara Calcinai ◽  
Cristina Gioia Di Camillo ◽  
...  

Coastal areas are known to receive significant anthropogenic inputs, mainly deriving from metropolitan areas, industries, and activities related to tourism. Among these inputs, some trace elements are listed as priority pollutants in the European Water Framework Directive, due to their ability to bioaccumulate in organisms. Many studies have been conducted on heavy metals (HMs) accumulation and on their possible effects on different edible marine species. While the most studied sessile organisms are bivalves, in the current review, we focus our attention on other sessile taxa (sponges, cnidarians, bryozoans, polychaetes, cirripeds, and tunicates), proposed as bioindicators in coastal shallow waters. Although their potential as bioindicator tools has been repeatedly highlighted in the literature, these organisms are still poorly investigated and considered for monitoring. In this context, we analyze the available literature about this topic, in order to summarize the current knowledge and identify possible applications of these organisms in a bioremediation scenario.


2014 ◽  
Vol 122 ◽  
pp. 105-115 ◽  
Author(s):  
Marion Cuif ◽  
David Michael Kaplan ◽  
Jérôme Lefèvre ◽  
Vincent Martin Faure ◽  
Matthieu Caillaud ◽  
...  

2022 ◽  
Vol 8 ◽  
Author(s):  
Chantel Elston ◽  
Paul D. Cowley ◽  
Rainer G. von Brandis ◽  
James Lea

Abiotic factors often have a large influence on the habitat use of animals in shallow marine environments. Specifically, tides may alter the physical and biological characteristics of an ecosystem while changes in temperature can cause ectothermic species to behaviorally thermoregulate. Understanding the contextual and relative influences of these abiotic factors is important in prioritizing management plans, particularly for vulnerable faunal groups like stingrays. Passive acoustic telemetry was used to track the movements of 60 stingrays at a remote and environmentally heterogeneous atoll in Seychelles. This was to determine if habitat use varied over daily, diel and tidal cycles and to investigate the environmental drivers behind these potential temporal patterns. Individuals were detected in the atoll year-round, but the extent of their movement and use of multiple habitats increased in the warmer NW-monsoon season. Habitat use varied over the diel cycle, but was inconsistent between individuals. Temperature was also found to influence stingray movements, with individuals preferring the deeper and more thermally stable lagoon habitat when extreme (hot or cold) temperature events were observed on the flats. Habitat use also varied over the tidal cycle with stingrays spending a higher proportion of time in the lagoon during the lowest tides, when movement on the flats were constrained due to shallow waters. The interplay of tides and temperature, and how these varied across diel and daily scales, dynamically influenced stingray habitat use consistently between three species in an offshore atoll.


2000 ◽  
Vol 14 (3) ◽  
pp. 327 ◽  
Author(s):  
Nils Møller Andersen ◽  
Tom A. Weir

Semiaquatic bugs (Heteroptera, infraorder Gerromorpha) are distributed worldwide with approximately 1,600 described species. Most species live in various types of freshwater habitats, but a little more than 10% have colonised the marine environment. The Australian fauna constitutes a significantly higher percentage of marine species (about 25%) than in any other continent. Among these are the coral treaders, Hermatobates Carpenter, belonging to the Hermatobatidae, one of very few insect families that only include marine species. In this paper the two species of Hermatobates previously known from Australia are redescribed and H. armatus, sp. nov. from the Chesterfield Islands in the Coral Sea is added. The distribution of species known from Australia and New Caledonia is mapped, and a revised key to the eight species currently recognised in the genus is presented. Finally, the available knowledge about the biology and ecology of coral treaders is reviewed and discussed.


Author(s):  
Charles Sheppard

Healthy reefs provide a habitat for an immense number of fish that come in a variety of shapes, sizes, and colours. No other natural habitat in the ocean shows this diversity and abundance. About a quarter of all marine species may be found on coral reefs even though this habitat occupies only one or two per cent of the area of the earth. ‘Reef fish and other major predators’ describes the diverse feeding ecology of reef fishes; coral reef predators such as the colourful crown of thorns starfish, Acanthaster plancii; symbiotic relationships between different species of fish or with different invertebrates; and the dangers of overfishing in reef communities.


2020 ◽  
Vol 238 ◽  
pp. 106708
Author(s):  
Massimiliano Drago ◽  
Meica Valdivia ◽  
Daniel Bragg ◽  
Enrique M. González ◽  
Alex Aguilar ◽  
...  

2020 ◽  
Vol 51 (1) ◽  
pp. 131-145 ◽  
Author(s):  
P. Maurizot ◽  
J. Collot ◽  
D. Cluzel ◽  
M. Patriat

AbstractThe Loyalty Ridge lies to the east and NE of the Norfolk Ridge. The three main Loyalty Islands (Maré, Lifou and Ouvéa) emerge from the ridge at the same latitude as Grande Terre. The islands are uniformly composed of carbonate deposits, except for Maré, where Middle Miocene intra-plate basalts and associated volcaniclastic rocks form restricted outcrops. Miocene rhodolith limestones constitute the bulk of the carbonate cover of the three islands. On Maré, these platform accumulations are locally topped by a dolomitic hardground, which, in turn, is covered by Pliocene–Pleistocene coral-bearing formations. These coral reef constructions are preserved as elevated rims over all three islands and define an atoll stage in their development. The Pleistocene–Holocene palaeoshoreline indicators include fringing bioconstructions and marine notches and record both eustatic sea-level changes and tectonic deformation. The ridge has been in the forebulge region in front of the active Vanuatu subduction zone since the Pliocene and each of the three islands has been uplifted and tilted to varying degrees. Offshore, the Loyalty Ridge continues northwards to the d'Entrecasteaux Zone and southwards to the Three Kings Ridge. Although typically volcanic, the nature of the deep Loyalty Ridge remains unknown.


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