Blacktip reef shark threats
The Blacktip Reef Shark is caught throughout its range in industrial and small scale longline, gillnet, trawl and handline fisheries that occur in continental shelf waters and those around oceanic islands and reefs, especially those around coral reefs. Most are taken as incidental catch in general reef fisheries targeting teleost fishes. For example, in the waters of the Great Barrier Reef it makes up 1.1% of shark catch in inshore gillnets (Harry et al. 2011) and 5% of sharks caught in the line fishery for reef teleosts (Heupel et al. 2009). In Indonesia it makes up 0.3% of the elasmobranch catch landed at the port of Muncar (Winter et al. In press). While in Fiji, Blacktip Reef Shark makes up more than half of the sharks landed in small scale artisanal coastal fisheries (Glaus et al. 2015). The species is also taken in small amounts by recreational fishers in some countries. There is limited species-specific catch trend data available for most countries, however, throughout much of the species' range there are intensive coastal fisheries that are likely to exert significant pressure on the stocks. In many parts of east Africa, and south and east Asian, there are large amounts of fishing effort targeted at carcharhinid sharks in continental shelf waters, and the effort continues to increase. For example, in the waters of Indonesia effort by small-scale fisheries has tripled when taking population into account (Ramenzoni 2017); and in Myanmar the International Labour Organisation (2015) estimated the number of vessels participating in the small scale inshore fishery to be about 26,000 in 2013, and the number of locally operated larger offshore vessels numbered 2,846 in 2013, having increased nearly 30% since 2009. Only in locations where fisheries are strictly regulated (e.g. Australia) (Espinoza et al. 2014), where human population densities are low (Nadon et al. 2012), or where dive-based tourism supports protection (Sutcliffe and Barnes 2018) are there low levels of threat that enable this species to remain common.
This species is a common display species in public and private aquaria. It is exported live from countries such as Australia and Indonesia to aquaria worldwide.
The reliance of this species 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 since 1997. Almost all warm-water coral reefs are projected to suffer significant losses of area and local extinctions, even if global warming is limited to 1.5 ºC (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.
