IUCN Red List Assessment LEAST CONCERN (2018)
Range Description: This species is distributed in the Indo-Pacific from East Africa (Kenya to Mozambique) to the central and southern Pacific from southern Japan to the Great Barrier Reef and Middleton Reef off Australia, and in the western Pacific to the Tuamotus and Pitcairn Island. It has also been recorded from the eastern coast of India (Visakhapatnam) as Plectropomus leopardus (Sujatha and Shrikanya 2012). Its depth range is four to about 100 metres.
Species Summary: This coral trout is widely distributed on outer coral reef slopes across the Indo-Pacific, and is naturally rare according to fishery-independent data. The sexual pattern of the species is monandric protogyny, i.e. all males develop from the sex change of adult females. The species is fast-growing with females reaching sexual maturity at 3 years and 40 cm SL. Sex change occurs at about 8 years of age. It is known to reach a maximum length of 130 cm TL and maximum age of 18-20 years. The species feeds on fishes and crustaceans and often forages quite widely high over the reef (https://www.youtube.com/watch?v=WBvUi5GvX-k). It sometimes hunts with other species, such as the trumpetfish.
The blacksaddled coral grouper displays a range of colour patterns and could sometimes be mistaken for the squaretailed coral grouper, P. areolatus. It has two basic colour forms but also a lot of variability in the intensity of the patterning, which can change quickly (https://www.youtube.com/watch?v=8d3zRtoJ9GY).
The pale, black-saddled form is whitish to yellowish with 5 dark saddles.
The darker form is brownish, blackish, reddish with the dark saddles less readily visible (but can always be discerned, even if faint).
In spawning aggregations, males exhibit a distinctive pattern of an almost black body, a light-coloured mid-ventral area and, at times, white lips.
The species forms small spawning aggregations to reproduce; an aggregation of 30 large fish was observed at Moore Reef GBR, Australia, in 2014 and of approximately 50 fish scattered along a reef slope off eastern Kadavu Island, Fiji, in 2011 at the August full moon (Sadovy 2011). One or a few males are seen with multiple (probable) females in small groupings above the reef. Small groups of reproductively active P. laevis have also been observed in French Polynesia (Tuamotus) and Papua New Guinea. Their aggregations often occur close to those of the camouflage grouper, brown-marbled grouper and squaretailed coral grouper.
Fisheries: This grouper is exploited through much of its range although fishery data are scant and it is often lumped in with other groupers, or combined with other Plectropomus species. It is heavily fished in parts of its range, for both chilled and live consumer markets, and declines are likely to have occurred in the Solomon Islands, the Maldives and Indonesia. However, the species is fast-growing and fishing is not considered to be a major threat on a global level at this time. It is listed as Least Concern on the IUCN Red List.
Management/Conservation: A key recommendation is to focus conservation and monitoring actions on spawning aggregations and reduce fishing effort, while also improving monitoring at the species level. Protection of spawning aggregations is also advised. There are several management measures in place, from minimum sizes (e.g. Maldives), to seasonal measures (e.g. Pohnpei) and spatial protection (e.g. Australia).
Key Recent Publications on biology, trade, fisheries and management: for earlier publications, please refer to IUCN Red List Assessment, https://www.springer.com/gp/book/9789400719798, and ‘Groupers of the World’: https://www.nisc.co.za/products/32/books/groupers-of-the-world-a-field-and-market-guide
Choat, J.H., Amorim, P., Sadovy, Y., Law, C., Suharti, S., Samoilys, M., Ma, K., To, A., Myers, R. and Rhodes, K. 2018. Plectropomus laevis.The IUCN Red List of Threatened Species 2018: e.T64412A100467190. https://dx.doi.org/10.2305/IUCN.UK.2018-2.RLTS.T64412A100467190.en.
Matley, J.K., Tobin, A.J., Ledee, E.J.I., Heupel, M.R., Simpfendorfer, C.A. 2016. Contrasting patterns of vertical and horizontal space use of two sympatric coral reef fish. Marine Biology 163(12): 253.
Matley, J. K., Maes, G. E., Devloo‐Delva, F., Huerlimann, R., Chua, G., Tobin, A. J., … and Heupel, M. R. 2018. Integrating complementary methods to improve diet analysis in fishery‐targeted species. Ecology and evolution, 8(18), 9503-9515. 492
Matley, J. K., Tobin, A. J., Simpfendorfer, C. A., Fisk, A. T., and Heupel, M. R. 2017. Trophic niche and spatio-temporal changes in the feeding ecology of two sympatric species of coral trout (Plectropomus leopardus and P. laevis). Marine Ecology Progress Series, 563, 197-210.