scholarly journals Diel rhythms in shallow Mediterranean rocky-reef fishes: a chronobiological approach with the help of trained volunteers

2012 ◽  
Vol 93 (2) ◽  
pp. 461-470 ◽  
Author(s):  
Ernesto Azzurro ◽  
Jacopo Aguzzi ◽  
Francesc Maynou ◽  
Juan José Chiesa ◽  
Dario Savini
Keyword(s):  
Marine Species ◽  
Reef Fishes ◽  
Rocky Reef ◽  
Natural Environments ◽  
Rocky Shores ◽  
Natural Systems ◽  
The Hours ◽  
Sarpa Salpa ◽  
Reef Fish Species ◽  
Rocky Reef Fish

Behavioural rhythms in marine species have been mostly investigated in laboratory organisms and their expression within the animals' natural environments remains largely unknown. Here, we studied diel (i.e. 24-hours-based) and intra-diel (i.e. 12-hours-based) rhythmic variations in the abundance of seven shallow rocky-reef fish species, namely Coris julis, Epinephelus marginatus, Sarpa salpa, Serranus cabrilla, Serranus scriba, Sparisoma cretense and Thalassoma pavo, along the rocky shores of Linosa Island (Mediterranean Sea). Data were visually collected by trained volunteers along fixed transects at 3-hourly intervals throughout six consecutive 24-hours periods. Density estimates can vary greatly between consecutive days and during 24-hours periods according not only to the major day–night changeover but also to minor intra-diel variations at the daylight hours. In the case of T. pavo, C. julis, S. cabrilla and S. salpa waveform analyses showed midday troughs in abundance within the 24-hours period but significant variation within the hours of daylight was highlighted only for T. pavo. Although results were not conclusive at the intra-dial level, the employment of volunteers represented a valuable tool for chronobiology, suitable to improve our understanding of fish behaviour in natural systems.

Unexpected effects of coastal storms on trophic ecology of two rocky reef fish species

2021 ◽  
Vol 168 (2) ◽  
Author(s):  
Javier Polanco-Pérez ◽  
Francesca V. Search ◽  
Patricio Winckler ◽  
María José Ochoa-Muñoz ◽  
Mauricio F. Landaeta
Keyword(s):  
Reef Fish ◽  
Fish Species ◽  
Trophic Ecology ◽  
Rocky Reef ◽  
Coastal Storms ◽  
Reef Fish Species ◽  
Rocky Reef Fish

scholarly journals Spatial dynamics of the Argentine sandperch, Pseudopercis semifasciata (Pinguipedidae), in temperate rocky reefs from northern Patagonia, Argentina

2014 ◽  
Vol 65 (1) ◽  
pp. 39 ◽  
Author(s):  
Leonardo A. Venerus ◽  
Alejo J. Irigoyen ◽  
David E. Galván ◽  
Ana M. Parma
Keyword(s):  
Spatial Dynamics ◽  
Reef Fishes ◽  
Conservation Strategies ◽  
Small Scale ◽  
Rocky Reef ◽  
San Jose ◽  
Northern Patagonia ◽  
Reef Fish Assemblage ◽  
Rocky Reefs ◽  
Rocky Reef Fish

The choice of appropriate conservation strategies for reef fishes depends on their mobility, degree of site fidelity and residence times. Here we report the results of a small-scale mark–recapture and resighting study conducted to investigate the spatial dynamics of the Argentine sandperch, Pseudopercis semifasciata. This is the flagship species of the rocky-reef fish assemblage from northern Patagonia, which has been the target of uncontrolled fishing since the early 1950s. About 19% of the fish tagged were recaptured up to four years after tagging. In total, 180 of 218 recaptured fish stayed in the reef of tagging. Thirty-six of 57 recaptures made at known locations within popular fishing areas of San José Gulf, densely covered by patchy reefs, occurred within 100 m of the tagging site, up to 793 days after tagging. Six fish were recovered more than 1 km from where they were tagged. Smaller fish were more prone to relocate, and were recovered farther from the tagging site. Fish stayed in the reefs for periods longer than a year; larger males remained longer in the same reefs. Our results indicate that relatively small reserves (in the order of a few kilometres) could be effective at protecting P. semifasciata populations within the northern Patagonian gulfs.

scholarly journals Mass mortality of foundation species on rocky shores: another reason why monitoring programs are relevant

2020 ◽  
Author(s):  
María M. Mendez ◽  
Juan P. Livore ◽  
Federico Márquez ◽  
Gregorio bigatti
Keyword(s):  
Large Scale ◽  
Marine Species ◽  
Foundation Species ◽  
Spatial And Temporal Variation ◽  
Marine Biodiversity ◽  
Natural Environments ◽  
Rocky Shores ◽  
Mussel Bed ◽  
Monitoring Programs

AbstractGlobal concern around substantial losses of biodiversity has led to the development of a number of large-scale long-term monitoring programs. In the past few decades, networks were established to obtain appropriate data on the spatial and temporal variation of marine species on rocky shores. Recently, the Marine Biodiversity Observation Network Pole to Pole of the Americas program (MBON P2P) was established and is coordinating biodiversity surveys along coastal areas throughout the continent. In this context, the goal of this paper was to demonstrate whether the proposed MBON P2P sampling protocol is capable of detecting rapid declines in cover of foundation species on Patagonian rocky shores. Changes in mussel beds cover were studied on monitored sites in northern Patagonia. Concurrently, long-term mussel bed dynamics were assessed based on existing data. Results showed that a mussel mortality event could be detected with this methodology. It took less than a year for mussel cover to drop from 90 to almost 0% despite the fact that significant changes in mussel bed cover were not registered in the previous 20 years at the study area. Therefore, yearly monitoring is needed, as a minimum, in order to timely perceive this kind of process. Real-time detection offers the opportunity of properly understanding the causes that lead to the loss of key community components such as these foundation species. Furthermore, it would provide early warning to decision makers enhancing the chances of conservation of natural environments and their key ecosystem services.

Effect of Iron Limitation on the Ultrastructure of Agmenellum Quadruplicatum

1981 ◽  
Vol 39 ◽  
pp. 410-411
Author(s):  
L. P. Hardie ◽  
D. L. Balkwill ◽  
S. E. Stevens
Keyword(s):  
Growth Medium ◽  
Green Alga ◽  
Natural Habitat ◽  
Iron Limitation ◽  
Natural Environments ◽  
Blue Green Alga ◽  
Marine Cyanobacterium ◽  
Natural Systems ◽  
Thin Sectioning ◽  
Agmenellum Quadruplicatum

Agmenellum quadruplicatum is a unicellular, non-nitrogen-fixing, marine cyanobacterium (blue-green alga). The ultrastructure of this organism, when grown in the laboratory with all necessary nutrients, has been characterized thoroughly. In contrast, little is known of its ultrastructure in the specific nutrient-limiting conditions typical of its natural habitat. Iron is one of the nutrients likely to limit this organism in such natural environments. It is also of great importance metabolically, being required for both photosynthesis and assimilation of nitrate. The purpose of this study was to assess the effects (if any) of iron limitation on the ultrastructure of A. quadruplicatum. It was part of a broader endeavor to elucidate the ultrastructure of cyanobacteria in natural systemsActively growing cells were placed in a growth medium containing 1% of its usual iron. The cultures were then sampled periodically for 10 days and prepared for thin sectioning TEM to assess the effects of iron limitation.

scholarly journals Influence of biopolymers on the rheological properties of seafloor sediments and the runout behavior of submarine debris flows

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jun Kameda ◽  
Hamada Yohei
Keyword(s):  
Rheological Properties ◽  
Debris Flows ◽  
Extracellular Polymeric Substances ◽  
Flow Behavior ◽  
Mass Movement ◽  
Rheological Parameters ◽  
Natural Environments ◽  
Natural Systems ◽  
Chemical Conditions ◽  
Seafloor Sediments

AbstractSubmarine debris flows are mass movement processes on the seafloor, and are geohazards for seafloor infrastructure such as pipelines, communication cables, and submarine structures. Understanding the generation and run-out behavior of submarine debris flows is thus critical for assessing the risk of such geohazards. The rheological properties of seafloor sediments are governed by factors including sediment composition, grain size, water content, and physico-chemical conditions. In addition, extracellular polymeric substances (EPS) generated by microorganisms can affect rheological properties in natural systems. Here we show that a small quantity of EPS (~ 0.1 wt%) can potentially increase slope stability and decrease the mobility of submarine debris flows by increasing the internal cohesion of seafloor sediment. Our experiments demonstrated that the flow behavior of sediment suspensions mixed with an analogue material of EPS (xanthan gum) can be described by a Herschel–Bulkley model, with the rheological parameters being modified progressively, but not monotonously, with increasing EPS content. Numerical modeling of debris flows demonstrated that the run-out distance markedly decreases if even 0.1 wt% of EPS is added. The addition of EPS can also enhance the resistivity of sediment to fluidization triggered by cyclic loading, by means of formation of an EPS network that binds sediment particles. These findings suggest that the presence of EPS in natural environments reduces the likelihood of submarine geohazards.

scholarly journals Using virtual reality to estimate aesthetic values of coral reefs

2018 ◽  
Vol 5 (4) ◽  
pp. 172226 ◽  
Author(s):  
Julie Vercelloni ◽  
Sam Clifford ◽  
M. Julian Caley ◽  
Alan R. Pearse ◽  
Ross Brown ◽  
...  
Keyword(s):  
Coral Reef ◽  
Coral Reefs ◽  
Structural Complexity ◽  
Natural Environments ◽  
Natural Ecosystems ◽  
Aesthetic Value ◽  
Natural Systems ◽  
Holistic Conservation ◽  
Past Experiences ◽  
Aesthetic Values

Aesthetic value, or beauty, is important to the relationship between humans and natural environments and is, therefore, a fundamental socio-economic attribute of conservation alongside other ecosystem services. However, beauty is difficult to quantify and is not estimated well using traditional approaches to monitoring coral-reef aesthetics. To improve the estimation of ecosystem aesthetic values, we developed and implemented a novel framework used to quantify features of coral-reef aesthetics based on people's perceptions of beauty. Three observer groups with different experience to reef environments (Marine Scientist, Experienced Diver and Citizen) were virtually immersed in Australian's Great Barrier Reef (GBR) using 360° images. Perceptions of beauty and observations were used to assess the importance of eight potential attributes of reef-aesthetic value. Among these, heterogeneity, defined by structural complexity and colour diversity, was positively associated with coral-reef-aesthetic values. There were no group-level differences in the way the observer groups perceived reef aesthetics suggesting that past experiences with coral reefs do not necessarily influence the perception of beauty by the observer. The framework developed here provides a generic tool to help identify indicators of aesthetic value applicable to a wide variety of natural systems. The ability to estimate aesthetic values robustly adds an important dimension to the holistic conservation of the GBR, coral reefs worldwide and other natural ecosystems.

scholarly journals Rocky reef fish assemblage structure in coastal islands of Southern Brazil

2015 ◽  
Vol 2 ◽  
Author(s):  
Daros Felippe ◽  
Bueno Leonardo ◽  
Soeth Marcelo ◽  
Bertoncini Athila ◽  
Hostim-Silva Mauricio ◽  
...  
Keyword(s):  
Reef Fish ◽  
Fish Assemblage ◽  
Assemblage Structure ◽  
Rocky Reef ◽  
Fish Assemblage Structure ◽  
Southern Brazil ◽  
Reef Fish Assemblage ◽  
Rocky Reef Fish

scholarly journals Reef fish community structure on three islands of Itaipu, Southeast Brazil

2008 ◽  
Vol 6 (2) ◽  
pp. 267-274 ◽  
Author(s):  
José Policarpo de Mendonça-Neto ◽  
Cassiano Monteiro-Neto ◽  
Luiz Eduardo Moraes
Keyword(s):  
Environmental Gradients ◽  
Seasonal Pattern ◽  
Reef Fishes ◽  
Habitat Characteristics ◽  
Brazilian Coast ◽  
Rocky Reef ◽  
Fish Community Structure ◽  
Rocky Reefs ◽  
Chain Link ◽  
One Year

We provide here the first assessment of the composition, abundance and distribution of rocky reef fishes of Itaipu Sound, Rio de Janeiro, off the southeastern Brazilian coast. Monthly visual censuses, benthic quadrats and chain link transects were conducted over one year on rocky reefs at three islands (Menina, Mãe and Pai). A total of 2466 individual fish, belonging to 29 families and 42 species were recorded. The most abundant fish species were Parablennius pilicornis, Haemulon steindachneri, Orthopristis ruber and Diplodus argenteus. Sheltered and complex habitats showed the most abundant and diverse fish populations. There was a major significant separation between sampling sites and a secondary seasonal pattern. The three sites showed similar fish communities with locally structured environmental gradients according to their inherent habitat characteristics.

scholarly journals Brazilian tropical fishes in their southern limit of distribution: checklist of Santa Catarina’s rocky reef ichthyofauna, remarks and new records

Check List ◽  
2015 ◽  
Vol 11 (4) ◽  
pp. 1688 ◽  
Author(s):  
Antônio Batista Anderson ◽  
Alfredo Carvalho-Filho ◽  
Renato Araujo Morais ◽  
Lucas Teixeira Nunes ◽  
Juan Pablo Quimbayo ◽  
...  
Keyword(s):  
Trophic Structure ◽  
New Records ◽  
Reef Fishes ◽  
Rocky Reef ◽  
Transitional Region ◽  
Southwestern Atlantic ◽  
Stegastes Partitus ◽  
Southern Limit ◽  
First Time ◽  
Tropical Ichthyofauna

We present a checklist of 278 species of reef fishes recorded along the coastline of Santa Catarina state, the southernmost limit of distribution of tropical ichthyofauna on the coast of Brazil. Twelve new species records for this state are presented: Acanthurus coeruleus, Acanthurus monroviae, Apogon americanus, Cantherhines macrocerus, Chaetodon sedentarius, Chromis flavicauda, Clepticus brasiliensis, Decapterus punctatus, Gymnothorax vicinus, Herpetoichthys regius, Muraena retifera and Stegastes partitus. Stegastes partitus and H. regius are reported for the first time, respectively, from the Southwestern Atlantic and for the coastal part of this region, while Acanthurus monroviae is reported for the second time for the Southwestern Atlantic. We present habitat distribution, trophic structure and comment on biogeographic affinities of this transitional region, discussing both remarkable species presences and absences.

Sign in / Sign up

Export Citation Format

Share Document