60 Abstract—Reproductive parameters of the white anglerfish (Lophius pis- Reproductive strategy of white anglerfish catorius) in the northwestern Medi- (Lophius piscatorius) in Mediterranean terranean Sea were studied in 556 specimens collected monthly aboard waters: implications for management commercial fishing vessels that were trawling at depths of 12–836 m. The main spawning season occurred from Ana I. Colmenero (contact author) February through June. The size at Víctor M. Tuset maturity was estimated to be 48.8 Pilar Sánchez cm in total length (TL) for males, 59.9 cm TL for females, and 51.3 Email address for contact author: [email protected] cm TL for both sexes combined. The white anglerfish has group-synchro- nous oocyte development and deter- Institut de Ciències del Mar (ICM) minate fecundity. It is a total spawn- Consejo Superior de Investigaciones Científicas (CSIC) er (spawns all its eggs once during Passeig Marítim de la Barceloneta 37-49 a spawning season) and has a batch 08003 Barcelona, Spain fecundity ranging from 661,647 to 885,214 oocytes, a relative batch fe- cundity of 66–128 oocytes per gram of female gutted weight, and a po- tential fecundity with values from 54,717 to 104,506 oocytes per kilo- The genus Lophius, commonly known which can be found on the conti- gram of female total weight. This as anglerfish, monkfish, or goosefish, nental shelf and slope, inhabiting study is the first to provide the re- belong to a family of bathydemersal depths from the shoreline to >1000 productive biology of white angler- fishes, which live and feed on the m (Afonso-Dias and Hislop, 1996). In fish in the northwestern Mediterra- bottom of the seafloor generally be- the Mediterranean Sea, this species nean Sea and provide valuable infor- mation that can be used to improve low 200 m (Caruso, 1986). It includes cohabits with black anglerfish, and the stock assessment and ensure 7 species distributed around the even though the distributions of both proper management of this species. world. The white anglerfish (Lophius species overlap, no ecological compe- piscatorius) is found in the northeast tition exists between them because of Atlantic Ocean and the Mediterra- a temporal segregation in their daily nean Sea, and the black anglerfish biorhythms (Colmenero et al., 2010). (Lophius budegassa) coexists with Both of these species of Lophius play white anglerfish over most of its an important role in the trophic range, although the black anglerfish structure of benthodemersal ecosys- has a more southerly distribution tems because they represent major in the Atlantic (Caruso, 1986). The predators, along with the European shortspine African angler (Lophius hake (Merluccius merluccius) (Díaz vaillanti) is found in the eastern At- et al., 2008). In the community struc- lantic (Maartens and Booth, 2005). ture of the northwestern Mediterra- The devil anglerfish (Lophius vome- nean Sea, species of anglerfish are rinus) occupies the southeast Atlan- considered top predators (Coll et al., tic and the northern and western In- 2006; Valls et al., 2014). They are also dian Ocean (Walmsley et al., 2005). reported to be important in the deep- The blackfin goosefish (Lophius sea community (depths from 200 m Manuscript submitted 2 November 2015. gastrophysus) inhabits the western to the bottom of the ocean) because Manuscript accepted 21 October 2016. Atlantic, and the goosefish (Lophius they are the most abundant species Fish. Bull. 115:60–73 (2017). americanus) occurs in the northwest (Labropoulou and Papaconstantinou, Online publication date: 15 November 2016. Atlantic (Caruso, 1983). Finally, the 2000; Maiorano et al., 2010). doi: 10.7755/FB.115.1.6. yellow goosefish (Lophius litulon) is Despite the fact that the deep distributed in the northwest Pacific, sea is the largest ecosystem on the The views and opinions expressed or implied in this article are those of the in the Gulf of Po-Hai, in the Yel- planet, is highly diverse, and has a author (or authors) and do not necessarily low Sea, and in the East China Sea wealth of resources, it is still mostly reflect the position of the National (Yoneda et al., 1997). unknown and poorly understood in Marine Fisheries Service, NOAA. We focused on white anglerfish, comparison with shallow-water ar- Colmenero et al.: Reproductive strategy of Lophius piscatorius in Mediterranean waters 61 eas: therefore environmental management in deep wa- dance, stock demography, and size at maturity. The lat- ters is difficult (Ramirez-Llodra et al., 2010). In the last ter work is valuable but is limited because sampling few decades, the decline of traditional fisheries on the occurred only in the spring and summer; a whole year continental shelf, the increasing demand for food sourc- of sampling is recommended to obtain more accurate es, and rapid technological developments have resulted biological information. in an increasing exploitation of deep-sea resources (Ko- A study of reproductive ecology is important for an slow et al., 2000; Ramirez-Llodra et al., 2011) and in understanding of population dynamics, and it is critical an incremental increase in the global mean depth of for assessing the effects of harvesting on fish popula- fishing (Watson and Morato, 2013). tions when attempting to develop appropriate manage- This rise in deep-sea fishing has affected catches ment strategies. Recruitment is recognized as a key of Lophius species, given the growing demand for hu- process for maintaining sustainable populations, and man consumption of this group of fish that is leading the relationship between the reproductive output of the to an increase in worldwide commercial exploitation population and the resulting recruitment is central to and targeting of anglerfishes (Fariña et al., 2008). To- understanding how a fish population will respond to tal catch reported globally for white anglerfish reached constant stressors such as fishing (Chambers and Trip- more than 26,500 metric tons (t) in 2014 (FAO Global pel, 1997). Although knowing more about the relation- Capture Production database, website) and total catch ships between life history strategies and productivity of anglerfishes in the northwestern Mediterranean with depth could help managers understand the poten- Sea for the same year added up to 660 t (Tudó Vila1). tial response of a deep-sea species to fishing (Drazen Landings in our study area were composed primarily and Haedrich, 2012), it is first necessary to conduct of black anglerfish (86%) and generally only a small biological studies of fish to gain knowledge of the re- percentage of white anglerfish (14%) (Tudó Vila1), but, productive system of a species (Koslow et al., 1995). for landings in Atlantic waters, the opposite is true; Such studies include gonad morphology (external and white anglerfish (94%) dominate the catch (Dobby et cellular description of the ovary and testis), reproduc- al., 2008). Although the European Commission previ- tive pattern (hermaphroditism or gonochorism), repro- ously has conducted stock assessments of black ang- ductive behavior, reproductive cycle, spawning season lerfish in the western Mediterranean Sea, there is no duration, size at maturity, sex ratio, size at sexual corresponding assessment for white anglerfish. The transition, and fecundity. lack of information about the structure of the popula- All of this information can be applied at the popu- tion of white anglerfish in this region and the lack of lation level to evaluate reproductive potential and to knowledge of the basic biology of this species are the serve as a basis for limits on fishing that aim in or- main reasons for the absence of any assessment. The der to keep recruitment at sustainable levels (García- actual management regulations applied for black ang- Díaz et al., 2006). Because reproductive strategy varies lerfish generally are those applied to bottom trawling within species, depending on the area of distribution of (European Union Council Regulation 1967/2006), with each species and the depth distribution of each species recommendations aimed at reducing the fishing effort in each area (Rotllant et al., 2002), there is a need for of the fleet in order to avoid loss in stock productivity knowledge about reproduction of deep-sea fish species. and decreases in landings (Cardinale et al.2). Such information is needed particularly in the Mediter- The small quantity of white anglerfish available ranean Sea because the data available for this region from landings in Mediterranean waters makes studies are limited (Morales-Nin et al., 1996; D’Onghia et al., of this species challenging. Studies conducted in the 2008; Muñoz et al., 2010; Bustos-Salvador et al., 2015), Mediterranean Sea have been scarce, and they have and, furthermore, target species of fisheries have been been focused on temporal and spatial distribution of the focus of only a few studies (Rotllant et al., 2002; this species (Ungaro et al., 2002; Colmenero et al., Recasens et al., 2008). 2010), age and growth (Tsimenidis and Ondrias, 1980; The goal of this study was to describe the reproduc- Tsimenidis, 1984), feeding ecology (López et al., 2016), tive parameters—gonadal morphology, spawning sea- morphometrics (Negzaoui-Garali and Ben Salem, 2008), son, size at sexual maturity, oocyte development, and parasites (Colmenero et al., 2015a), and ova character- fecundity—of white anglerfish in the northwestern istics (Colmenero et al., 2015b). Among these studies, Mediterranean Sea in order to provide valuable infor- only Ungaro et al. (2002) analyzed some of the biologi- mation and scientific background to improve stock as- cal features of this species by using data available from sessments and effective management for Lophius spe- trawl surveys, including data on distribution, abun- cies in Mediterranean waters. 1 Tudó Vila, P. 2015. Unpubl. data. Directorate of Fishing and Maritime Affairs, Government of Catalonia, Avinguda Materials and methods Diagonal 523-525, 08029 Barcelona, Spain. 2 Cardinale, M., D. Damalas, and C. G. Osio (eds.). 2015.