Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2021 Nov 16:9:e12412.
doi: 10.7717/peerj.12412. eCollection 2021.

Nighttime migrations and behavioral patterns of Pempheris schwenkii

Keita Koeda  1   2 , Hideyuki Touma  3 , Katsunori Tachihara  4
Affiliations

Nighttime migrations and behavioral patterns of Pempheris schwenkii

Keita Koeda et al. PeerJ. .

Abstract

Background: Although the biomass of the nocturnal fishes is almost same as that of diurnal fishes, most of the ecological studies that examine feeding or reproductive behaviors are on diurnal fishes. Therefore, there is limited ecological information regarding the nocturnal fishes. This fact may be attributed to the difficulty in observing them during darkness. Members of the genus Pempheris (Pempheridae) are one of the most abundant nocturnal fishes on coral reefs.

Methods: The nighttime migrations of Pempheris schwenkii were observed by attaching a chemical luminescent tag. Tagged fishes were followed by an observer without torch and SCUBA, and their positions and estimated depths were plotted on an underwater topographic map. Aquarium tank observation was carried out to further describe their habits during the night.

Results: The new tagging method provided good data for observing the migration behavior. In all five observations, the target fishes started nighttime migration from the entrance of their cave within 1 h after sunset. All of them immediately left the inner reef and spent most of the observation time near the surface (0-5 m depth) or shallow (5-15 m depth) water-columns of the outer reef. Their migration pattern varied between days, but they migrated long distance (379-786 m/h) during each observation. The behavior observed in the aquarium tank was categorized into five patterns: schooling, shaking, migrating, spawning, and feeding. Shaking and spawning were observed during one of three observation days.

Discussion: The present study firstly clarified the small-scale but dynamic nocturnal migration pattern of P. schwenkii in nature by a new method using chemical luminescent tags. In addition, combined observations from nature and an aquarium could be used to estimate the behavior of this species. Pempheris schwenkii may reduce their predation risk of eggs and adults by spawning at outer reef in nighttime. It was estimated that they can potentially migrate 4-7 km/night. The rapid growth known for this species may have been supported by their feeding behavior where they can fill up their stomach every night with rich zooplankton in outer reefs. Furthermore, the behavior of this species indicates the possibility that they make an important contribution to the flow of energy and materials in their coral reef ecosystem.

Keywords: Coral reef; Ecosystem; Feeding behavior; Keystone; Nocturnal; Observation; Pempheridae; Reproduction; Sweepers; Trophic link.

PubMed Disclaimer

Conflict of interest statement

Hideyuki Touma is employed by the Okinawa Churaumi Aquarium.

Figures

Figure 1
Figure 1. Photographs and illustration of chemical luminescence tagged Pempheris schwenkii swimming in the cave with untagged individuals.
(A) Long shot; (B) close up; (C) diagram.
Figure 2
Figure 2. Diagram of the tank in Churaumi Aquarium viewed directly from above.
Observation area was separated to six stations.
Figure 3
Figure 3. Tracks of migration of Pempheris schwenkii.
Plots indicating lat/log data for every 30 s of the first an hour after they start migration. The estimated swimming depth in each data are shown by different colors of plots, such as white (surface water-column: <5 m depth), light grey (shallow water-column: 5–15 m depth), and dark grey (deep water-column: >15 m depth). The accumulated swimming distance (m) of each direction is shown at upper right. (A) 22-May; (B) 27-May; (C) 29-May; (D) 31-May; (E) 8-June; (F) 5 days combined.
Figure 4
Figure 4. Illustration of five patterns of behavior of Pempheris schwenkii as observed during tank observation.
Figure 5
Figure 5. Time schedule of behavior (black bars) and locality (colored bars) of Pempheris schwenkii as observed in tank observation with varying light intensity (black line).
The characters indicate observed five behavioral patterns as follows: S, schooling; W, swinging; M, migrating; F, feeding; P, spawning.
See this image and copyright information in PMC

References

    1. Alldredge AL, King JM. Distribution, abundance, and substrate preferences of demersal reef zooplankton at Lizard Island lagoon, Great Barrier Reef. Marine Biology. 1977;41(4):317–333. doi: 10.1007/BF00389098. - DOI
    1. Annese D, Kingsford M. Distribution, movements and diet of nocturnal fishes on temperate reefs. Environmental Biology of Fishes. 2005;72(2):161–174. doi: 10.1007/s10641-004-0774-7. - DOI
    1. Bardach JE. On the movements of certain Bermuda reef fishes. Ecology. 1958;39(1):139–146. doi: 10.2307/1929976. - DOI
    1. Bray RN, Miller AC, Geesey GG. The fish connection: a trophic link between planktonic and rocky reef communities? Science. 1981;241(4517):204–205. doi: 10.1126/science.214.4517.204. - DOI - PubMed
    1. Esquivel-Garrote O, Morales-Ramírez A. Nocturnal variation of the zooplankton community in coral reef substrates at Isla del Coco National Park (Eastern Tropical Pacific) Revista de Biología Tropical. 2020;68(1):S261–S270. doi: 10.15517/rbt.v68iS1.41189. - DOI

LinkOut - more resources