Peer Review #1 of "In situ effects of simulated overfishing and eutrophication on settlement of benthic coral reef invertebrates in the Central Red Sea (v0.1)"

In the Central Red Sea, relatively pristine coral reefs meet intense coastal development, but data on the effects of related stressors for reef functioning are lacking. This in situ study therefore investigated the independent and combined effects of simulated overfishing and eutrophication on settlement of reef associated invertebrates on light-exposed and -shaded tiles over 4 months. Findings revealed that at the end of the study period invertebrates had almost exclusively colonized shaded tiles, indicating that algae were superior settling competitors on light-exposed tiles. On the shaded tiles, simulated overfishing prevented settlement of hard corals, but significantly increased settlement of polychaetes, while simulated eutrophication only significantly decreased hard coral settlement relative to controls. The combined treatment significantly increased settlement of bryozoans and bivalves compared to controls and individual manipulations, but significantly decreased polychaetes compared to simulated overfishing. These results suggest settlement of polychaetes and hard corals as potential bioindicators for overfishing and eutrophication, respectively, and settlement of bivalves and bryozoans for a combination of both. Therefore, if investigated stressors are not controlled, phase shifts from dominance by hard corals to that by other invertebrates may occur at shaded reef locations in the Central Red Sea.

Download Full-text

In situ effects of simulated overfishing and eutrophication on settlement of benthic coral reef invertebrates in the Central Red Sea

10.7287/peerj.preprints.227v1 ◽

2014 ◽

Cited By ~ 1

Author(s):

Christian Jessen ◽

Christian R. Voolstra ◽

Christian Wild

Keyword(s):

Coral Reef ◽

Coral Reefs ◽

Red Sea ◽

Combined Treatment ◽

Coastal Development ◽

Combined Effects ◽

Hard Coral ◽

Coral Settlement ◽

In Situ Study

In the Central Red Sea, relatively pristine coral reefs meet intense coastal development, but data on the effects of related stressors for reef functioning are lacking. This in situ study therefore investigated the independent and combined effects of simulated overfishing and eutrophication on settlement of reef associated invertebrates on light-exposed and -shaded tiles over 4 months. Findings revealed that at the end of the study period invertebrates had almost exclusively colonized shaded tiles, indicating that algae were superior settling competitors on light-exposed tiles. On the shaded tiles, simulated overfishing prevented settlement of hard corals, but significantly increased settlement of polychaetes, while simulated eutrophication only significantly decreased hard coral settlement relative to controls. The combined treatment significantly increased settlement of bryozoans and bivalves compared to controls and individual manipulations, but significantly decreased polychaetes compared to simulated overfishing. These results suggest settlement of polychaetes and hard corals as potential bioindicators for overfishing and eutrophication, respectively, and settlement of bivalves and bryozoans for a combination of both. Therefore, if investigated stressors are not controlled, phase shifts from dominance by hard corals to that by other invertebrates may occur at shaded reef locations in the Central Red Sea.

Download Full-text

Year-round high abundances of the world’s smallest marine vertebrate (Schindleria) in the Red Sea and worldwide associations with lunar phases

Scientific Reports ◽

10.1038/s41598-021-93800-w ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Vanessa Robitzch ◽

Victor Molina-Valdivia ◽

Jaiber J. Solano-Iguaran ◽

Mauricio F. Landaeta ◽

Michael L. Berumen

Keyword(s):

Coral Reef ◽

Reef Fish ◽

Red Sea ◽

Coral Reef Fish ◽

Seasonal Temperature ◽

Global Trends ◽

Lunar Phases ◽

Spatial Differences ◽

New Moon ◽

Reproductive Cycles

AbstractVery little is known about the ecology and biology of the smallest marine vertebrates, fishes in the genus Schindleria. Even though over half of named Schindleria species have been identified in the Red Sea, the collection of only very few specimens has been documented. Here, we assessed abundance patterns of nearly two thousand Red Sea long dorsal fin (LDF) adults and found evidence for putative seasonal and spatial differences, likely related to differing habitat and environmental conditions. The highest abundances were outside local seasonal temperature extremes and decoupled from peaks of coral reef fish recruitment. We also found evidence for global trends in abundances related to lunar cycles using our Red Sea data and that from a recently published large collection of specimens from the DANA Expedition (1928–1930). The abundance of adult LDF Schindleria in relation to lunar phases differed significantly, with most Schindleria caught outside the full moon, and mostly during the new moon in the Red Sea and the 3rd quarter moon in the DANA collection. We further suggest that the abundances of Schindleria at coral reefs may be related to reproductive cycles and that these cycles may be timed with the moon as back-calculations of hatch dates from otoliths from the Red Sea significantly resulted after the new moon, making Schindleria the fastest-lived coral reef fish with the shortest generation times. Schindleria could be the most numerous coral reef fish in the world, for which we encourage increased research.

Download Full-text