Ecological networks among key target fish species in Kenya (2015-2022).

Barnes, Michele L.; Graham, Nicholas A. J.; McClanahan, Tim; Matous, Petr; Bartelet, Henry A.

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Open Access

Field	Value	Language
dc.contributor.author	Barnes, Michele L.
dc.contributor.author	Graham, Nicholas A. J.
dc.contributor.author	McClanahan, Tim
dc.contributor.author	Matous, Petr
dc.contributor.author	Bartelet, Henry A.
dc.coverage.spatial	Kenya	en_AU
dc.coverage.temporal	2015-2022	en_AU
dc.date.accessioned	2025-01-24T00:11:38Z
dc.date.available	2025-01-24T00:11:38Z
dc.date.issued	2025-01-24
dc.identifier.uri	https://hdl.handle.net/2123/33547
dc.description.abstract	Trophic interactions (i.e., predator-prey relationships) among target fish species comprising the majority of catch by all fishing gears employed along the Kenyan coast.	en_AU
dc.language.iso	en	en_AU
dc.rights	Creative Commons Attribution-NonCommercial-ShareAlike 4.0	en_AU
dc.subject	ecological network	en_AU
dc.subject	trophic foodweb	en_AU
dc.subject	coral reef	en_AU
dc.subject	coral reef fisheries	en_AU
dc.subject	Kenya	en_AU
dc.title	Ecological networks among key target fish species in Kenya (2015-2022).	en_AU
dc.type	Dataset	en_AU
dc.subject.asrc	ANZSRC FoR code::41 ENVIRONMENTAL SCIENCES	en_AU
dc.subject.asrc	ANZSRC FoR code::44 HUMAN SOCIETY	en_AU
dc.identifier.doi	10.25910/b0r9-tm65
dc.relation.arc	DE190101583
dc.description.method	To determine which species were caught by each gear type being used by fishers across our study sites, we used a long-term fish catch dataset collected by our partners at the Wildlife Conservation Society. The dataset included surveys from 27 landing sites along the Kenyan coast conducted continuous between January 2015 and December 2022, although no data was collected in the year 2020 because of the COVID-19 pandemic. For each observation, onsite observers identified landed catch at the species level in addition to the gear used. Observers were present at landing stations every sampling day before the arrival of boats and stayed until the entire landing process was concluded. Although all patrols were conducted during daylight hours, the sampling method does not exclude catches attributed to nighttime fishing activities, as observers also intercepted fishers returning from their overnight fishing, ensuring that each gear used at each site was sampled and that each species landed was recorded. The number of patrols conducted per month were not stratified, but similar intervals of sampling were maintained within this randomized block design to detect long-term catch trends. An observed total of 14,524 individual fish caught across all gear types was reported between January 2015 and December 2022. We divided the fish catch data set into three subsets to analyze whether the types of fish species caught by different fishing gears changed meaningfully over time. Here we looked at three time periods (2015-2016, 2018-2019, and 2021-2022) and seven different gear types. Our analysis did not indicate meaningful trends in the types of fish species caught by different fishing gears. We therefore continued our analysis with constant gear-species relationships over time, as well as constant ecological network configurations. Most gears used in multispecies coral reef fisheries incidentally catch several species infrequently (i.e., bycatch). We therefore focused on species comprising most of the total catch for each gear type, excluding all species that comprised less than 3% of the total catch in all of three time periods we included in our analysis. Our analysis identified 47 individual fish species that had at least >3% of the total fish catch per gear type in one of the three time periods Trophic interactions capturing predator-prey relationships among the 47 target fish species were estimated based on a combination of diet, relative body size, and habitat use (likelihood of encounter). The corresponding ecological network was thus undirected, with edges representing trophic interactions between fish species (Fig. S2). Diet and body size (maximum length) data were taken from FishBase (1, 2), and broad patterns of habitat use (i.e., pelagic, demersal, coral-dominated, macroalgal bed) were estimated from published records and expert first-hand knowledge (TRM, NAJG, ASH). Detail on the specific fish species consumed from analyses of gut contents is largely unavailable, yet piscivorous coral reef fish are known to be generalists in terms of the species they consume (3). We thus took a conservative approach, considering one species to prey on another if its diet was predominantly piscivorous, its body length was large (ca. ≥ 2 times) compared to that of the prey species, and the two species occupied a similar habitat. We did not identify potential predatory links for any species whose diet was not primarily piscivorous as any likely predation on other targeted species was likely to be too infrequent to have a meaningful effect on prey populations. References 1. R. Froese, D. Pauly, Eds., FishBase 2000: Concepts, designs and data sources (The WorldFish Center, 2000). 2. R. Froese, D. Pauly, FishBase, version (06/2023). (2023). Available at: https://www.fishbase.se/search.php [Accessed 22 October 2023]. 3. E. S. Hobson, Feeding relationships of teleostean fishes on coral reefs in Kona, Hawaii. Fish. Bull. 72, 915–1031 (1974).	en_AU
usyd.faculty	SeS faculties schools::Faculty of Engineering::School of Project Management	en_AU
workflow.metadata.only	No	en_AU