The Sharptooth Lemon Shark is caught throughout much of its range in industrial and small-scale longline, gillnet, trawl, and handline fisheries that occur in coastal waters, including around coral reefs and mangrove habitats. It is retained for the meat and fins where possible. There is little data available on the capture of this species in fisheries of island nations in the Pacific Ocean where the species show little trend in population size. Throughout the coastal waters of Asia, it is caught in gillnets, longlines, trawls and handlines and landed. However, in recent years it has rarely been reported in surveys of landings sites. For example, Winter et al. (2020) reported a single individual in landings at Muncar in Indonesia in a 9 month period in 2017–2018. Similar levels of paucity of catch are reported in Thailand (Arunrugstichai et al. 2018), Philippines (Bureau of Fisheries and Aquatic Resources 2017) and Sri Lanka (Dissanayake 2005). In the Arabian Seas region, there is little species-specific data on Sharptooth Lemon Shark catch but generally, carcharhinids there are susceptible to and caught in a variety of fishing gear types, particularly gillnets and longlines, as well as trawl nets (which generally capture smaller individuals and species). Fisheries in the region have experienced increased demand for sharks since the 1970s due to the shark fin trade and as a result, effort is increasing in traditional shark fisheries in many areas (Bonfil 2003, Henderson et al. 2007, Jabado et al. 2015). Simultaneously, there has been a significant increase in coastal fishing effort and power in some parts of the Arabian Seas region leading to a reduction in the number of shark catches (e.g., De Silva 2006, Spaet and Berumen 2015). For example, in the Red Sea, the number of traditional boats operating more than tripled from about 3,100 to 10,000 between 1988 and 2006 (Bruckner et al. 2011).
In Australia, this species is caught in coastal gillnet, longline, and trawl fisheries in northern waters. For example, Harry et al. (2011) reported that it made up 0.3% of the gillnet catch (in numbers) in Queensland. It is taken in the North Prawn Fishery, with estimates of fishing mortality below those that would lead to population decline (Zhou and Griffiths 2008). It is also captured in small amounts in the North Territory Offshore Net and Line Fishery, Northern Territory Barramundi Fishery, and Western Australia Kimberley Gillnet and Barramundi Fishery (Simpfendorfer et al. 2019). The Sharptooth Lemon Shark was identified as a minor component of the large and prevalent Illegal, Unreported and Unregulated fishing (IUU) in northern Australian waters during the early 2000s (Field et al. 2009, Marshall 2011). However, the IUU fishing has declined significantly since 2006 due to increased border surveillance, international agreements, and possibly increased fuel prices and reduction in target shark species (Field et al. 2009, Haward and Bergin 2016).
The reliance of the Sharptooth Lemon Shark on coral reefs makes it susceptible to declines in habitat quality. Global climate change has already resulted in large-scale coral bleaching events with increasing frequency causing worldwide reef degradation. Almost all warm-water coral reefs are projected to suffer significant losses of area and local extinctions, even if global warming is limited to 1.5ºC (IPCC Report, 2019). Destructive fishing practices in some nations (e.g. dynamite fishing) (McManus 1997) and declining water quality (MacNeil et al. 2019) have also led to the decline in coral reef habitat.
The reliance of this species on mangrove habitats, especially as pupping and nursery grounds makes them susceptible to declines in habitat quality. The extent of mangrove habitat has declined markedly, with 20-35% of areas lost during the last half of the 20th century (Polidoro et al. 2010) as a result of coastal development for urbanisation, aquaculture and agriculture, timber harvesting sand resource extraction (Goldberg et al. 2020).
