African Journal of Aquatic Science ISSN: (Print) (Online) Journal homepage: https://www.tandfonline.com/loi/taas20 Habitat utilisation of Pseudobarbus afer and Sandelia capensis in headwaters of the Swartkops River, Eastern Cape, South Africa B Hannweg , SM Marr , LE Bloy & OLF Weyl To cite this article: B Hannweg , SM Marr , LE Bloy & OLF Weyl (2020): Habitat utilisation of Pseudobarbusafer and Sandeliacapensis in headwaters of the Swartkops River, Eastern Cape, South Africa, African Journal of Aquatic Science, DOI: 10.2989/16085914.2020.1719815 To link to this article: https://doi.org/10.2989/16085914.2020.1719815 Published online: 12 Jun 2020. Submit your article to this journal Article views: 6 View related articles View Crossmark data Full Terms & Conditions of access and use can be found at https://www.tandfonline.com/action/journalInformation?journalCode=taas20 African Journal of Aquatic Science 2020: 1–9 Copyright © NISC (Pty) Ltd Printed in South Africa — All rights reserved AFRICAN JOURNAL OF AQUATIC SCIENCE This is the final version of the article that is published ISSN 1608-5914 EISSN 1727-9364 ahead of the print and online issue https://doi.org/10.2989/16085914.2020.1719815 Habitat utilisation of Pseudobarbus afer and Sandelia capensis in headwaters of the Swartkops River, Eastern Cape, South Africa B Hannweg1,2, SM Marr2,3* , LE Bloy1,2,3 and OLF Weyl2,3,1 1 Department of Ichthyology and Fisheries Science, Rhodes University, Makhanda, South Africa 2 DSI/NRF Research Chair in Inland Fisheries and Freshwater Ecology, South African Institute for Aquatic Biodiversity, Makhanda, South Africa 3 Centre for Invasion Biology, South African Institute for Aquatic Biodiversity, Makhanda, South Africa *Correspondence: [email protected] Habitat degradation is one of the greatest threats to endemic freshwater fish in the Cape Fold Ecoregion. One habitat restoration strategy is the replication of critical habitat using artificial materials. In this paper, we evaluate the habitat occupancy of two small, endemic headwater fish of the Cape Fold Ecoregion, namely the Eastern Cape redfin Pseudobarbus afer (Peters, 1864) and the Cape Kurper Sandelia capensis (Cuvier, 1829). Habitat occupancy was observed in five pool microhabitats (inflow, woody debris, deep open, fern-root wads, and outflow) using action cameras. Changes in habitat occupancy were assessed following the introduction of an artificial habitat in the form of PVC pipes. Pseudobarbus afer preferred deeper open habitats, whereas Sandelia capensis preferred more structured woody debris habitat. Habitat occupancies differed significantly across all microhabitats for both species; excluding those between the inflow and outflow, and the open deep and fern-root wads for Sandelia capensis. Pseudobarbus afer and S. capensis occupancies in the natural microhabitats reduced significantly following the introduction of the artificial habitat. For species restricted to degraded habitats that require habitat restoration, the use of artificial habitat may be beneficial in accelerating the recovery of such species. Keywords: action cameras, artificial habitat, conservation, endangered fish, headwater streams, maxN, proportional occupancy Supplementary material: available online at https://doi.org/10.2989/16085914.2020.1719815 Introduction Globally, freshwater ecosystems are facing a variety of 2008); e.g. food, shelter, predator avoidance, breeding human-mediated threats and a large number of species are habitat, etc. (Odling-Smee et al. 2011). Therefore, at risk of population declines towards extinction (Darwall conservation strategies for species at risk must protect or et al. 2018). Threats, including habitat degradation/ restore specific habitats within water bodies, especially fragmentation/alteration and siltation, water pollution, critical habitats (Rosenfeld and Hatfield 2006), and the overabstraction and flow modification, and the introduction connectivity between these habitats. However, habitat of non-native fish species (Darwall et al. 2018), are requirements through the entire life cycle of most fish are compounded for species isolated within headwater streams poorly understood (Fausch et al. 2002) and understanding or with restricted geographical distributions (Ellender et the association between habitat and the wellbeing of fish al. 2017). The Cape Fold Ecoregion, sensu Abell et al. populations is required for efficient, effective conservation (2008), is a hotspot of endemism and threatened freshwater or restoration strategies (Rabeni and Sowa 1996). fish species in southern Africa (Tweddle et al. 2009). One approach to restoring habitat is the replication of The greatest threats to the fish of this ecoregion are the the natural habitat using artificial materials (Seaman and presence of non-native fish species and habitat degradation Sprague 1991). Globally, artificial structures have been (Tweddle et al. 2009; Ellender et al. 2017). Although deployed in marine and freshwater systems to create projects to address the threats of non-native fish have been habitat for a variety of aquatic organisms (Seaman and executed (Weyl et al. 2014; Shelton et al. 2017; van der Sprague 1991). Artificial habitats can be used as freshwater Walt et al. 2019), restoration of riverine habitat has received fish conservation measures to boost population numbers less attention. There is, therefore, a requirement to start by providing habitats important to their specific life histories researching the restoration of riverine habitat for the fish of (Schlaepfer et al. 2005; Yokomizo et al. 2007; Westhoff et the Cape Fold Ecoregion. al. 2013). Fish have been found to utilise artificial habitats Habitat requirements of fish species are dependent on for refuge or foraging in situ (Clark and Edwards 1999; Pratt their specific life-cycle stage (Schlosser 1991) and their et al. 2005; Santos et al. 2008) and in the laboratory (Kadye specific requirements in each life stage (Orpwood et al. and Booth 2014; Magellan and García-Berthou 2015). African Journal of Aquatic Science is co-published by NISC (Pty) Ltd and Informa UK Limited (trading as Taylor & Francis Group) Published online 12 Jun 2020 2 Hannweg, Marr, Bloy and Weyl Fish habitat analysis in streams can be conducted at of the Swartkops River, Eastern Cape, South Africa, in two complementary levels: 1) behavioural associations of the Groendal Wilderness Area. The Fernkloof River lies individuals at a microhabitat scale, and 2) associations of entirely within the Groendal Wilderness Area and has been populations with larger-scale habitat elements (Rabeni minimally impacted by human activities. Sites comprised and Sowa 1996). Population-level analysis highlights the of four pool habitats selected on the basis of the presence importance of fluvial dynamics, whereas microhabitat of the target species, having suitable water clarity for analysis highlights local scale habitat elements that could underwater photography, and containing the five selected explain fish abundance and distributions (Rabeni and Sowa microhabitats: inflow (shallow, fast, turbulent water at the 1996). This paper aims to conduct a microhabitat analysis head of the pool), outflow (shallow, slow water at the tail of for two small, endemic, headwater fish species, Eastern the pool), deep open (open water at the deepest point in the Cape redfin Pseudobarbus afer (Peters, 1864) and Cape pool), woody debris (branches and twigs in the pool) and Kurper Sandelia capensis (Cuvier, 1829), in the field using fern-root wads (each pool had a rock face on one bank that an underwater-camera array to (1) demonstrate the use had ferns growing on the waterline with their root wads in of action cameras to determine the habitat occupancy; (2) the water). assess the differences in the habitat occupancy for each Water physico-chemical parameters, pH, temperature of the species; (3) assess the difference in the habitat (°C), and electrical conductivity (µs cm−1), were measured occupancy between the two species and (4) assess using a HANNA HI98129 combo probe (HANNA the change in the habitat occupancy of the two species Instruments, Inc., United States of America.). A portable following the introduction of an artificial habitat. The HANNA HI 98703 turbidity meter (HANNA Instruments, Inc., two species co-occur throughout the P. afer distribution United States of America.) was used to measure turbidity range, and S. capensis co-occurs with Pseudobarbus (NTU). Three measurements of each parameter were species throughout its distributions range. Both species recorded at the inflow, deep open, and outflow sites of each occur predominantly in pools although P. afer frequently pool and averaged for the visit. forage in riffles (Skelton 2001). Although some research has been conducted on the breeding behaviour of both Baseline habitat utilisation species (Cambray 1990, 1994, 2004), the interaction The relative abundance of P. afer and S. capensis in each between the aggressive and territorial S. capensis and the microhabitat of each pool was estimated using five GoPro placid and schooling P. afer has not been explored. The Hero 3+ (GoPro Inc., USA) action cameras, in waterproof hypotheses for this work were 1) there is no difference in housings mounted on tripods; one covering each of the microhabitat occupancy for each of the species; 2) there selected microhabitats: inflow, outflow, deep open, woody is no difference in microhabitat occupancy between the debris, and fern-root wads. Cameras were set to