MARINE ECOLOGY FIELD COURSE
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University of Neuchâtel - Switzerland
First Marine Biology Field Trip For Master Students
For the first time, the University of Neuchâtel organized a field trip in Dahab, Egypt. Master students had the opportunity to discover the incredible biodiversity present on coral reefs and work on various small projects, supervised by members of the Eco-Ethology lab of Prof. Redouan Bshary. This website is the product of their work during this one-week field trip.
RED SEA LIFE
// GALLERY
2016 Student Research Projects
01
Do reef fishes use localized defecation sites depending on their foraging behavior?
Understanding the mechanisms underlying reef sedimentation and the systematic use of localized defecation sites (LDS, i.e. underwater latrines) is a still unexplored research area within the behavioral complexity of coral reel ecology. It might also have important consequences for coral reef conservation strategies, as fish sedimentation could potentially accelerate the erosion rates of coral calcareous structures or even promote algal growth (fertilization), thus competing with coral growth. Our research interest was focused on localized defecation site observations across several species of common reef fishes, and to assess whether a pattern emerges relatively to taxon, diet, defecation site structure and distance from foraging area. From our observations we couldn't demonstrate any systematic use of LDS in the coral reef but some behavioral patterns nonetheless emerged, relating differing foraging habits with traveling distances from feeding to waste disposal sites, across three family of common reef fishes: butterflyfishes, surgeonfishes and parrotfishes.
Malika Rinsoz, Livio Ruzzante
02
Do the abundance and the diversity of fishes vary with the size and the type of corals?
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Coral reefs are considered as the most diverse marine habitat nowadays. As the Red sea is characterisc and has features that lack in other reefs around the indo-pacific oceanic region, it is a favourable habitat to analyse the abundance and the diverstiy of species present in coral reefs. Here, we measured the abundance and the diversity of fishes present at the coral reef of Abu Sauatir, near El Quseir, in the south of Egypt. We predicted that the type and the size of corals influence the abundance and the diversity of fishes. Thus, during a period of five days, we selected five commun types of coral at the study area and made observations of the number of individuals and the different families of fishes present per types of coral. The statistical analysis revealed only one signifcative results but we could observed that some coral's types had more individuals present than others. Moreover, the analysis of the diversity of fishes at the area was at an average of species richness. At last, we concluded that the size and the type are not factors that influence the abundance and the diversity of fishes. Thus, further studies are needed to better understand the great diversty found in coral reef ecosystems.
Lara Bernasconi, Jennifer Gier and Alessia Wolf
03
Are Sohal surgeonfish (Acanthurus sohal) more willing to chase fish that can compete for food resources in a 1-meter diameter around them?
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Sohal surgeonfish (Acanthurus sohal) are an abundant grazing species leaving in shallow coral reefs, a highly productive marine ecosystem in which competition for food resources is a daily struggle. The Sohal surgeonfish is known to aggressively defend its feeding territory against intruders. The aim of our project was to establish if the species A. sohal tolerates some families more than others in a 1-meter range around it. We expect that the intensity of the agonistic reaction will be adjusted regarding the potential competitive threat of the intruder fish. Thus, we predict herbivorous families to be more at risk to be chased than carnivorous or omnivorous species. Thus, we went to the Red Sea at El-Quseir, Egypt, where we followed 44 different surgeonfish between 6 and 10 minutes, wrote down every fish family entering a 1-meter range around the focals and all aggressive behaviours conducted by the surgeonfish. Our results show that herbivorous are more exposed to agonistic behaviours of A. sohal. As a conclusion, diet seems to be a determining factor for territoriality and interspecific tolerance for Sohal surgeonfish.
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Léonore Bonin, Cloé Brachotte and Adrian Herrera
04
Does the presence of divers have an effect on diversity, abundance and size of clients at cleaner wrasse (Labroides dimidiatus) cleaning stations?
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Many behavioral studies imply a researcher presence to observe the animals. However, what is the effect of the observer on the behavior of the studied individuals? In this project, we use coral reef fish species interacting with the blue streak cleaner wrasse (Labroides dimidiatus) as an example. The cleaner fish is a territorial fish, living in cleaning stations. They interact with other fish species, commonly called clients. The cleaners clean client reef species from thier ectoparasites. We placed GoPro cameras on 23 cleaning stations in the Red Sea. In the first condition, two scuba diving observers stayed by the station and there was no observer in the second condition. The objective is to film the cortège of fish swimming by the cleaning stations and to measure the effect of the observer. We found that the divers’ presence has, as assumed, a negative impact on fish diversity. However, the abundance was not significantly different, neither the mean size of species coming to the stations. For further studies including fish behavior within cleaning stations, we consequently recommend to consider the impact of the presence of observers.
Lorraine Delisle, Elena Levorato & William McNeely
2015 Student Research Projects
01
Does coral structural complexity affect fish biodiversity ?
In this project, the aim was to study the possible link between corals and species of fish. We focused on the structural complexity of corals and hypothesized that corals considered as “complex” in their morphology (such as arbuscular species) may promote biodiversity of fish by increasing the number and size of possible shelter for various species. Therefore, 1) we counted the different damselfish species in a rectangular area and then, 2) we measured with a quadrat the percentage of different structural categories of corals in this area. No significant correlations were found between biodiversity and coral complexity. However, the number of fish (all species together) was favored by a higher proportion of complex corals. This project illustrates that many factors are affecting fish communities in coral reefs and that the structural effect of this unique environment is difficult to evaluate.
Adrien Bottarelli - Martin Jeanmonod - Sylvain Lanz
02
Impact of observers on fish diversity and size at common cleaner wrasse (Labroides dimidiatus) cleaning stations
We carried on a pilot project focused on the possibility that the presence of human observers might influence the behaviour of fishes on the coral reef. In particular, we focused our attention on the regions of the reef called cleaning station, where cleaner wrasses (Labroided dimidiatus) interact with theirs client fishes. We therefore filmed nine cleaning stations for 15 minutes with and without the presence of human observers. Thus we compared the number of families and species of fishes that visited the stations. Moreover, we looked at the average “maximal” size of those fishes. Our results showed that the presence of observers did reduce the number of families, species and the maximal size of fishes visiting the cleaning stations. We therefore suggest that more attention on this effect should be paid in future studies.
Camille Demairé, Simona Colosio & Fausto Quattrini
03
Spatial distribution of invertebrates in Red Sea coral reefs
This project aimed to describe the spatial distribution of reef dwelling organisms. For that we used invertebrates because they are abundant on the coral reef surface and have diverse ecological requirements. We took data every 2m along the reef edge. For each data point, we noted whether the first invertebrate seen was in the light, shade, exposed or sheltered. The most common organisms were clams, anemones, brittle stars, sea urchins and christmas tree worms. Brittle stars preferred sheltered over exposed patches. These are territorial organisms, which defend their crevices against conspecifics. Sea urchins showed the same preference for shelter. They erode the substrate while feeding on algae, creating cavities around them. These and other results suggested us why reef dwelling organisms are found in different patches with dissimilar light and exposure conditions depending on their ecological requirements and behaviours.
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Maxime Clerc, Alvaro Sobrino & Arnaud Strubin