My master's thesis project examined microhabitat association of gobies and other small, cryptic fishes in the central Red Sea. To put it simply, a microhabitat is defined as a subset of a larger habitat. Some examples include: the bark of a tree, a specific coral head on a reef, a patch of stones, etc. Gobies are of particular interest to me because they are one of the most speciose families of fish. There are over 1,800 species in the family Gobiidae, with more being discovered every year. Gobies are also very small, often no larger than a few cm in length. Despite their size, they are incredibly numerous on coral reefs. However, being cryptic, they are hard to sample. Visual surveys of reef fish will often not account for them because gobies are small and like to hide in small cracks and crevices. A good way to account for these species on a reef is to use an ichthyocide (like rotenone) when sampling. I looked at 3 different microhabitat types: hard corals, sand, and dead coral rubble. Once I found a suitable site, I placed a 1m x 1m quadrat over the chosen microhabitat. I had a net to place over top the quadrat, to prevent fish from escaping. Then I administered the rotenone and waited about 5 minutes for everything to settle. After the time was up, the net was removed and the fish were collected. After I collected my samples, I took the fish back to the lab and photographed each one individually. Then, I cataloged and identified them using both morphological and genetic methods. I used DNA barcoding as an identification tool and the DNA sequences I obtained from my samples are uploaded to public sequence databases, such as GenBank. They will be useful to future researchers and provide genetic information about these understudied species. I collected over 300 individuals and found that even at small scales of a few square meters, benthic composition influences community structure of cryptobenthic fishes in the Red Sea. Fish assemblages differed significantly across all three habitats, with rubble habitats having the highest levels of fish abundance, species richness, and diversity, followed by hard coral, and then sand. Boxplots displaying abundance (number of individuals per m2), species richness (number of species per m2), and diversity (H′) for all collected fishes (A, C, E) and for family Gobiidae (B, D, F) for each of the three microhabitat types sampled using rotenone stations (1 m2 quadrats, n = 5 quadrats per microhabitat type) in the central Saudi Arabian Red Sea. Asterisks denote significant pairwise groupings (*p < 0.05, **p < 0.01, ***p < 0.001). This work is important because the Red Sea is a historically understudied area in regards to biodiversity. Gobies and other cryptobenthic fishes are also understudied due to their cryptic and hidden nature. It is my hope that this project will raise awareness of cryptobenthic fish biodiversity in the Red Sea and provide a basis for future work regarding Red Sea species. This work was recently published in PeerJ: Troyer EM, Coker DJ, Berumen ML. (2018) Comparison of cryptobenthic reef fish communities among microhabitats in the Red Sea. PeerJ 6:e501 https://doi.org/10.7717/peerj.5014
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AuthorThis blog will be where I will talk about my research experience and where it has taken me over the years. Archives
July 2019
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