Evaluation of a low-cost, non-invasive survey technique to assess the relative abundance, diversity and behaviour of sharks on Sudanese reefs (Southern Red Sea)

Abstract

A low-cost and non-invasive survey technique focused on pelagic sharks was evaluated during an ecotourism cruise on two Sudanese reefs, Angarosh and Sha'ab Rumi, in the Southern Red Sea. The research technology was based on a set of small, underwater video recording cameras and a pair of laser pointers. Video footage provided insight into shark biodiversity on the two reefs, detecting five species, Alopias vulpinus, Sphyrna lewini, Triaenodon obesus, Carcharhinus amblyrhynchos and Galeocerdo cuvier, during 15.8 h of video recording. These recordings also provided preliminary information on aggregations of S. lewini. The laser pointers were used to measure the size of sharks, providing seven total length (TL) measurements for S. lewini (N = 2) and C. amblyrhynchos (N = 5), confirming the possibility of easily obtaining size parameters using this tool. These low-cost and user-friendly instruments provide ecotourism divers with an opportunity to become involved in marine research projects.

Reef sharks: recent advances in ecological understanding to inform conservation

“…melanopterus and C . perezi , activity space appears to increase with size and juveniles typically use shallower habitat closer to shore such as lagoons (Garla et al , ; Chin et al , 2013 a ; Rezzolla et al , ; Table SI, Supporting Information). On the Great Barrier Reef, the larger C .…”

“…Methods with higher detection abilities, but lower accuracy, such as baited video surveys, may also be desired when reef sharks are rarer, as found at heavily fished localities or if only presence–absence or relative abundance data are desired for studies of species richness or composition (Dennis et al , ; Heagney et al , ; Brooks et al , ; Bond et al , ; McCauley et al , 2012 b ; Ruppert et al , ; Espinoza et al , ; Rizzari et al , 2014 b ). Video surveys can also be used if estimates of total biomass are desired given the ease and accuracy of measuring size on video (Goetze & Fullwood, ; Rezzolla et al , ). BRUVs are only slightly less accurate and efficient than typical fisheries‐dependent methods of estimating abundance and are also non‐invasive (Brooks et al , ).…”

Data‐mining social media platforms highlights conservation action for the Mediterranean Critically Endangered blue shark Prionace glauca

“…Critical habitats need to be identified for conservation and management purposes (Bradai, Saidi & Enajjar, 2012; Moore, 2018), especially considering that the distribution of threatened elasmobranchs is not homogenous throughout the Mediterranean Sea (Coll et al, 2010; Boldrocchi et al, 2017). Data deficiency in shark ecology is also a widespread problem (Bradai, Saidi & Enajjar, 2012), as conducting ecological field studies is often very expensive (Rezzolla, Boldrocchi & Storai, 2014; Moore, 2018). New approaches are needed to compensate for such a paucity of data (Bargnesi, Lucrezi & Ferretti, 2020).…”

Water temperature and precipitation stimulate small-sized Japanese eels to climb a low-height vertical weir

“…Video imaging is an effective tool for wild animal research, including studies on animal diversity, abundance, and behavior [ 52 ]. Being non-invasive, video imaging allows for target species to be studied in their habitats without any disturbance [ 53 , 54 ]. Recently, ecological monitoring using video systems has become more applicable in a broader range of situations owing to the technological developments in cameras, such as extended battery life and increased storage capacity [ 55 , 56 ].…”