The threatened status of restricted-range coral reef fish species

Abstract

Coral reefs are the most diverse ecosystem in the sea. Throughout the world they are being overfished, polluted and destroyed, placing biodiversity at risk. To date, much of the concern over biodiversity loss has centred on local losses and the possibility of global extinction has largely been discounted. However, recent research has shown that 24% of reef fish species have restricted ranges (< 800 000 km 2 ), with 9% highly restricted (< 50 000 km 2 ). Restricted-range species are thought to face a greater risk of extinction than more widespread species since local impacts could cause global loss. We searched for information on status in the wild and characteristics of 397 restricted-range reef fish species. Fish body size, habitat requirements and usefulness to people were compared with those of a taxonomically-matched sample of more widespread species. We found that on average species with restricted ranges were significantly smaller (mean total length 19.1 cm versus 24.4 cm), tended to have narrower habitat requirements and were less used by people. Greater habitat specificity will tend to increase extinction risk while, if real, more limited usefulness (equivalent to exploitation) may reduce risk. Fifty-eight percent of restricted-range species were considered common/abundant in the wild and 42% uncommon/rare. Population status and threats to 319 species for which data were available were assessed according to the categories and criteria of the IUCN red list of threatened animals. A number of species were found to be rare, were exploited and had highly restricted ranges overlapping areas where reef degradation is particularly severe, placing them at a high risk of extinction. Five species were listed as Critically Endangered, two of them possibly already extinct in the wild, one as Endangered and 172 as Vulnerable. A further 126 species fell into Lower Risk categories and 11 were considered Data Deficient. Given the intensity of impacts to reefs, the broad geographical areas affected and the large numbers of restricted-range species, global extinctions seem likely. Urgent management action is now crucial for the survival of several species of reef fishes.

Biology of extinction risk in marine fishes

“…Recent assessments of tropical coral reef species, for example, indicate that many have small, restricted population sizes, which may render them highly vulnerable to human activities (Hawkins et al 2000). In most parts of the world, coral reefs are declining rapidly, with 20% of the world's reefs having been destroyed with little prospect for recovery in the near future (Wilkinson 2004).…”

Spearfishing pressure on fish communities in rocky coastal habitats in a Mediterranean marine protected area

“…These species can be fished down to a vulnerable level because of their economic, aesthetic or gastronomic value. In particular, fish living in rock and reef habitats seem to be particularly vulnerable to exploitation as a result of their life history traits (Jennings et al, 1999;Hawkins et al, 2000).…”

International Trade in Marine Aquarium Species: Using the Global Marine Aquarium Database

“…In the Philippines many reefs have been destroyed by dynamite fishing and smothered under sediments washing out from clear-cut forests, yet collectors may be threatening the survival of rare fish by removing them from these already stressed ecosystems. This claim is made in the same article (Hawkins and Roberts 2000) for the bluespotted angelfish (Chaetodontoplus caeruleopunctatus). The gravity of the situation for everyone involved in the aquarium industry should not be underestimated, for there is nothing the public understands more readily than the extinction of a beautiful creature.…”

“…Anyone disagreeing with the conclusion published recently in a scientific journal that "its [the Banggai cardinalfish] status in the wild is precarious, with heavy collecting [for aquariums] continuing" (Hawkins and Roberts 2000) would find it difficult to produce a counterargument because no one has any idea how many Banggai cardinalfish are traded. Some sympathy is surely owed to those people whose task it is to set policies that balance the need for conservation with the regulation of a potentially sustainable industry that employs thousands of people and provides high incentives for reef stewardship.…”