Contents lists available at ScienceDirect Fisheries Research journal homepage: www.elsevier.com/locate/fishres Length-frequency data approaches to evaluate snapper and grouper fsheries in the Java Sea, Indonesia Patrícia Amorim a,b,c, *, Pedro Sousa c , Ernesto Jardim d , Manuela Azevedo e , Gui M. Menezes a a University of the Azores, OKEANOS Research Unit, Institute of Marine Research (IMAR), Horta, Azores, Portugal b Marine and Environmental Sciences Centre (MARE), Azores, Portugal c Sustainable Fisheries Partnership Foundation (SFP), Honolulu, USA d European Commission, Joint Research Centre (JRC), Ispra, Italy e Instituto Português do Mar e da Atmosfera (IPMA), Lisbon, Portugal ARTICLEINFO Handled by A.E. Punt Keywords: Snapper Grouper Indonesia Length-based methods Data-limited fsheries ABSTRACT Indonesia is the most important producer country of snapper and grouper species worldwide, with a notable increase in landings over the past decades. The Java Sea is one of the most frequently fshed areas for these species in Indonesia, but in 2016 a decrease in landings was observed. This study applied two approaches (Length-based Indicators and Length-Structured Growth-Type-Group Model) to assess the status of snapper and grouper fsheries in the Java Sea, using length-composition data from the commercial fshery and covering multiple gears with diferent selectivity. The work focused on the dominant species in the catches: Malabar blood snapper (Lutjanus malabaricus), Areolate grouper (Epinephelus areolatus), Crimson snapper (Lutjanus ery- thropterus), and Goldbanded jobfsh (Pristipomoides multidens). Considerable diferences were observed, related to the type of gear used. Catch data obtained from the longline fshery presented good stock status indicators for all species studied. The spawning potential ratio (SPR) estimates calculated for Malabar blood snapper and crimson snapper indicated that these species are currently fshed in the Java Sea at unsustainable levels (below 30 % SPR) by the dropline and mixed-gear feets, while areolate grouper and goldbanded jobfsh are not overfshed (above 30 % SPR). For both methods, bias in L inf and, secondarily, bias in M/K have a stronger infuence on the indicators values, in particular for the proportion of individuals above the length of optimal yield + 10 % (P mega ) estimates and SPR, than bias in L mat values. This study highlighted other areas where improvements are critical to ensure the sustainability of the snapper and grouper fsheries in the Java Sea. 1. Introduction Indonesia is the most important producer country of snapper and grouper species worldwide (e.g., Amorim et al., 2018; Newman et al., 2017), contributing 36 % of the global capture production of these species (2016 data; FAO, 2018). According to the global capture pro- duction dataset provided by the Food and Agriculture Organization of the United Nations (FAO), about 137,000 tonnes of snappers (jobfshes included) and 144,000 tonnes of groupers were landed in Indonesia during 2016 (FAO, 2018). The reported landings of these species have been increasing in recent years; at the start of the 2000s, landings were around 120,000 tonnes for both groups of species lumped together (FAO, 2018). The snappers (Lutjanus species), collectively referred to as kakapmerah or bambangan in Indonesia (“red snappers”), and jobfshes (Pristipomoides spp.) belong to the family Lutjanidae. Groupers (locally called kerapu) are usually defned as species of subfamily Epinephelinae, although in Indonesia a variety of genera comprise this group (e.g., Epinephelus, Cephalopholis, Plectropomus). These species are targeted together by demersal fsheries (between 50–500 meters depth), usually referred to in Indonesia as “deepwater snapper and grouper fsheries,” which also target other species such as emperors (Lethrinidae), grunts (Haemulidae), and various species of at least ten other families (Satria et al., 2019). In Indonesia, most communities are located in coastal areas, and fshisoneof the main sources of protein for the population (Aransyach, 2017). Furthermore, national fsh consumption is increasing every year, expected to grow from an estimated consumption of 46.5 kg/capita/ year in 2017 to 54.5 kg/capita/year in 2019 (BPS- Statistics Indonesia, 2018; CEA and Green, 2018). However, the life-history characteristics of the snappers and groupers (e.g., slow-growing, late maturing, sea- sonal spawning aggregations), combined with external threats (such as nursery habitat destruction, juvenile extraction, use of destructive https://doi.org/10.1016/j.fshres.2020.105576 Received 19 December 2019; Received in revised form 23 March 2020; Accepted 25 March 2020 ⁎ Corresponding author at: University of the Azores, Department of Oceanography and Fisheries, Rua Prof. Dr. Frederico Machado, Horta, Azores, Portugal. E-mail address: amorim.patricia@gmail.com (P. Amorim). Fisheries Research 229 (2020) 105576 0165-7836/ © 2020 Elsevier B.V. All rights reserved. T