Citation:

PANGAEA.942667

Name: Fish abundance in Changuu Island (Unguja Island, Zanzibar Archipelago, Tanzania)
Published: 2022-03-24
License: https://creativecommons.org/licenses/by/4.0/
Keywords: grazing; seagrass traits; sea urchin; tropical seagrass

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Abstract:

We deployed underwater cameras (GoPro Hero3) to measure the abundance of predators of T. gratilla. According to previous literature, the main fish predators of T. gratilla in this region were Balistapus undulatus (Triggerfish, family Balistidae) and Cheilinus undulatus (Wrasse, family Labridae) (McClanahan and Muthiga, 1989; McClanahan and Shafir, 1990; Eklöf et al., 2009). Abundances of these predators in our study site were the main focus of these surveys.

We deployed the cameras in four sampling events: 22.07.2017 (three cameras), 07.08.2017 (seven cameras), 28.08.2017 (six cameras) and 30.09.2017 (six cameras). We deployed three cameras simultaneously, attached to a 50 cm tall wooden pole. Each camera recorded a mean (± standard error) of 53 ± 2 minutes and an area of 10 m2, resulting in a total of ~20 hours of video and a total surveyed area of ~220 m2. We used the maximum count method for counting fishes in the video surveys (Conn, 2011). We counted the fishes as the number of times they appear in the recorded area (i.e. if one fish left the area recorded and appeared again, it was counted as a new fish, as defined by Conn, 2011). This method was used to ensure that any predatory fish of T. gratilla would be detected despite the likely over-estimation of fish counts of abundant fish families. The fishes that appeared in the videos were screenshotted and identified using the fish identification guide developed by Allen et al. (2003). We created one category per fish family identified, two individual categories for the fish species that are predators of T. gratilla (B. undulatus and C. undulatus) and one category for unidentifiable fishes (generally due to suboptimal visibility). The final number of fishes is the individuals count.

Keyword(s):

grazing; seagrass traits; sea urchin; tropical seagrass

Supplement to:

Moreira-Saporiti, Agustín; Hoeijmakers, Dieuwke; Reuter, Hauke; Msuya, Flower E; Gese, Katrin; Teichberg, Mirta (2023): Bottom‐up and top‐down control of seagrass overgrazing by the sea urchin Tripneustes gratilla. Marine Ecology, 44(1), e12734, https://doi.org/10.1111/maec.12734

Further details:

Conn, Paul B (2011): An evaluation and power analysis of fishery independent reef fish sampling in the Gulf of Mexico and U.S. South Atlantic. U.S. DEPARTMENT OF COMMERCE, NOAA technical memorandum NMFS-SEFSC

Eklöf, Johan S; Fröcklin, Sara; Lindvall, Annika; Stadlinger, Nadja; Kimathi, Alex; Uku, Jacqueline N; McClanahan, Tim R (2009): How effective are MPAs? Predation control and 'spill-in effects' in seagrass-coral reef lagoons under contrasting fishery management. Marine Ecology Progress Series, 384, 83-96, https://doi.org/10.3354/meps08024

McClanahan, Tim R; Muthiga, Nyawira A (1989): Patterns of preedation on a sea urchin, Echinometra mathaei (de Blainville), on Kenyan coral reefs. Journal of Experimental Marine Biology and Ecology, 126(1), 77-94, https://doi.org/10.1016/0022-0981(89)90125-1

McClanahan, Tim R; Shafir, S H (1990): Causes and consequences of sea urchin abundance and diversity in Kenyan coral reef lagoons. Oecologia, 83, 362-370, https://doi.org/10.1007/BF00317561

Coverage:

Latitude: -6.117806 * Longitude: 39.167383

Date/Time Start: 2017-07-22T00:00:00 * Date/Time End: 2017-09-30T00:00:00

Minimum Elevation: 0.0 m * Maximum Elevation: 0.0 m

Event(s):

Unguja_Island_Changuu4 * Latitude: -6.117806 * Longitude: 39.167383 * Date/Time: 2017-07-22T00:00:00 * Elevation: 0.0 m * Location: Zanzibar Archipealgo, Tanzania * Method/Device: Digital Camera, GoPro (GOPRO) * Comment: The sampling sites consisted of subtidal meadows (1-4 meters depth) of around 2500 square meters, delimited by the coastline and a fringing reef.

Unguja_Island_Changuu5 * Latitude: -6.117806 * Longitude: 39.167383 * Date/Time: 2017-08-07T00:00:00 * Elevation: 0.0 m * Location: Zanzibar Archipealgo, Tanzania * Method/Device: Digital Camera, GoPro (GOPRO) * Comment: The sampling sites consisted of subtidal meadows (1-4 meters depth) of around 2500 square meters, delimited by the coastline and a fringing reef.

Unguja_Island_Changuu6 * Latitude: -6.117806 * Longitude: 39.167383 * Date/Time: 2017-08-28T00:00:00 * Elevation: 0.0 m * Location: Zanzibar Archipealgo, Tanzania * Method/Device: Digital Camera, GoPro (GOPRO) * Comment: The sampling sites consisted of subtidal meadows (1-4 meters depth) of around 2500 square meters, delimited by the coastline and a fringing reef.

Parameter(s):

#	Name	Short Name	Unit	Principal Investigator	Method/Device	Comment
1	Event label	Event		Moreira-Saporiti, Agustín
2	Site	Site		Moreira-Saporiti, Agustín
3	Time in minutes	Time	min	Moreira-Saporiti, Agustín		Video length
4	Visibility	Visibility		Moreira-Saporiti, Agustín
5	Balistapus undulatus	B. undulatus	#	Moreira-Saporiti, Agustín	Counting fishes in the video surveys (Conn, 2011)
6	Cheilinus undulatus	C. undulatus	#	Moreira-Saporiti, Agustín	Counting fishes in the video surveys (Conn, 2011)
7	Balistidae	Balistidae	#	Moreira-Saporiti, Agustín	Counting fishes in the video surveys (Conn, 2011)
8	Labridae	Labridae	#	Moreira-Saporiti, Agustín	Counting fishes in the video surveys (Conn, 2011)
9	Pomacentridae	Pomacentridae	#	Moreira-Saporiti, Agustín	Counting fishes in the video surveys (Conn, 2011)
10	Apogonidae	Apogonidae	#	Moreira-Saporiti, Agustín	Counting fishes in the video surveys (Conn, 2011)
11	Lethrinidae	Lethrinidae	#	Moreira-Saporiti, Agustín	Counting fishes in the video surveys (Conn, 2011)
12	Lutjanidae	Lutjanidae	#	Moreira-Saporiti, Agustín	Counting fishes in the video surveys (Conn, 2011)
13	Siganidae	Siganidae	#	Moreira-Saporiti, Agustín	Counting fishes in the video surveys (Conn, 2011)
14	Carangidae	Carangidae	#	Moreira-Saporiti, Agustín	Counting fishes in the video surveys (Conn, 2011)
15	Sphyraena	Sphyraena	#	Moreira-Saporiti, Agustín	Counting fishes in the video surveys (Conn, 2011)
16	Chaetodontidae	Chaetodontidae	#	Moreira-Saporiti, Agustín	Counting fishes in the video surveys (Conn, 2011)
17	Mullidae	Mullidae	#	Moreira-Saporiti, Agustín	Counting fishes in the video surveys (Conn, 2011)
18	Tetraodontidae	Tetraodontidae	#	Moreira-Saporiti, Agustín	Counting fishes in the video surveys (Conn, 2011)
19	Monacanthidae	Monacanthidae	#	Moreira-Saporiti, Agustín	Counting fishes in the video surveys (Conn, 2011)
20	Gobiidae	Gobiidae	#	Moreira-Saporiti, Agustín	Counting fishes in the video surveys (Conn, 2011)
21	Fish school	Fish school	#	Moreira-Saporiti, Agustín	Counting fishes in the video surveys (Conn, 2011)	Small fish school
22	Pisces indeterminata	Pisces indet	#	Moreira-Saporiti, Agustín	Counting fishes in the video surveys (Conn, 2011)
23	Pisces	Pisces	#	Moreira-Saporiti, Agustín	Counting fishes in the video surveys (Conn, 2011)	Total

License:

Creative Commons Attribution 4.0 International (CC-BY-4.0)

Status:

Curation Level: Enhanced curation (CurationLevelC)

Size:

484 data points

Data

Download dataset as tab-delimited text — use the following character encoding:

1 Event	2 Site	3 Time [min]	4 Visibility	8 Labridae [#]	9 Pomacentridae [#]	10 Apogonidae [#]	11 Lethrinidae [#]	12 Lutjanidae [#]	13 Siganidae [#]	14 Carangidae [#]	15 Sphyraena [#]	16 Chaetodontidae [#]	17 Mullidae [#]	18 Tetraodontidae [#]	19 Monacanthidae [#]	20 Gobiidae [#]	21 Fish school [#]	22 Pisces indet [#]	23 Pisces [#]
Unguja_Island_Changuu4	Changuu4	41	Great	9	2	21	5	0	0	0	0	0	0	0	0	0	9	2	48
Unguja_Island_Changuu4	Changuu4	39	Great	3	7	29	0	0	6	0	0	0	0	0	0	0	4	1	50
Unguja_Island_Changuu4	Changuu4	39	Great	11	1	12	10	3	54	0	0	0	0	0	4	0	3	9	107
Unguja_Island_Changuu5	Changuu5	35	Regular	5	0	2	0	1	0	0	0	0	0	0	0	0	0	1	9
Unguja_Island_Changuu5	Changuu5	35	Good	15	5	11	3	4	0	1	0	0	0	0	0	0	4	1	44
Unguja_Island_Changuu5	Changuu5	46	Great	22	26	10	4	3	1	0	60	0	0	0	0	0	15	8	149
Unguja_Island_Changuu5	Changuu5	46	Bad	9	39	0	2	1	0	0	0	0	0	0	2	0	5	109	167
Unguja_Island_Changuu5	Changuu5	52	Great	15	2	4	1	2	0	0	0	0	0	0	0	19	2	3	48
Unguja_Island_Changuu5	Changuu5	42	Regular	7	5	19	1	1	0	0	0	0	0	0	1	1	0	6	41
Unguja_Island_Changuu5	Changuu5	72	Great	14	8	13	21	11	11	0	0	0	0	1	2	2	14	22	119
Unguja_Island_Changuu6	Changuu6	57	Good	21	0	1	4	7	1	0	0	0	0	0	0	0	1	11	46
Unguja_Island_Changuu6	Changuu6	52	Regular	27	191	24	1	1	0	0	0	0	0	0	0	0	7	22	273
Unguja_Island_Changuu6	Changuu6	65	Great	53	0	2	4	5	0	0	0	2	2	0	0	0	4	5	77
Unguja_Island_Changuu6	Changuu6	70	Great	51	1	21	3	5	1	1	0	0	0	0	0	0	9	0	92
Unguja_Island_Changuu6	Changuu6	52	Good	3	3	4	2	3	0	0	0	0	0	1	0	0	2	4	22
Unguja_Island_Changuu6	Changuu6	52	Good	0	2	2	0	0	0	1	0	0	0	0	0	0	0	5	10
Unguja_Island_Changuu7	Changuu7	75	Good	139	6	9	7	0	0	0	0	0	0	2	0	0	1	16	180
Unguja_Island_Changuu7	Changuu7	56	Regular	14	1	1	1	5	0	0	0	0	0	0	0	0	1	9	32
Unguja_Island_Changuu7	Changuu7	52	Regular	9	3	1	1	1	0	0	0	0	2	0	0	0	0	16	33
Unguja_Island_Changuu7	Changuu7	76	Great	43	0	1	2	5	0	0	0	0	0	0	0	0	0	2	53
Unguja_Island_Changuu7	Changuu7	52	Great	2	0	1	5	2	0	0	0	0	0	0	0	0	2	2	14
Unguja_Island_Changuu7	Changuu7	70	Regular	9	0	0	8	3	0	0	0	0	0	0	0	0	3	19	42