Colmenero et al.; Reproductive strategy of Lophius piscatorius in Mediterranean waters 
61 
eas: therefore environmental management in deep wa- 
ters is difficult (Ramirez-Llodra et al., 2010). In the last 
few decades, the decline of traditional fisheries on the 
continental shelf, the increasing demand for food sourc- 
es, and rapid technological developments have resulted 
in an increasing exploitation of deep-sea resources (Ko- 
slow et al., 2000; Ramirez-Llodra et al., 2011) and in 
an incremental increase in the global mean depth of 
fishing (Watson and Morato, 2013). 
This rise in deep-sea fishing has affected catches 
of Lophius species, given the growing demand for hu- 
man consumption of this group of fish that is leading 
to an increase in worldwide commercial exploitation 
and targeting of anglerfishes (Farina et al., 2008). To- 
tal catch reported globally for white anglerfish reached 
more than 26,500 metric tons (t) in 2014 (FAO Global 
Capture Production database, website) and total catch 
of anglerfishes in the northwestern Mediterranean 
Sea for the same year added up to 660 t (Tudo Vila^). 
Landings in our study area were composed primarily 
of black anglerfish (86%) and generally only a small 
percentage of white anglerfish (14%) (Tudo Vila^), but, 
for landings in Atlantic waters, the opposite is true; 
white anglerfish (94%) dominate the catch (Dobby et 
ah, 2008). Although the European Commission previ- 
ously has conducted stock assessments of black ang- 
lerfish in the western Mediterranean Sea, there is no 
corresponding assessment for white anglerfish. The 
lack of information about the structure of the popula- 
tion of white anglerfish in this region and the lack of 
knowledge of the basic biology of this species are the 
main reasons for the absence of any assessment. The 
actual management regulations applied for black ang- 
lerfish generally are those applied to bottom trawling 
(European Union Council Regulation 1967/2006), with 
recommendations aimed at reducing the fishing effort 
of the fleet in order to avoid loss in stock productivity 
and decreases in landings (Cardinale et al.^). 
The small quantity of white anglerfish available 
from landings in Mediterranean waters makes studies 
of this species challenging. Studies conducted in the 
Mediterranean Sea have been scarce, and they have 
been focused on temporal and spatial distribution of 
this species (Ungaro et al., 2002; Colmenero et ah, 
2010), age and growth (Tsimenidis and Ondrias, 1980; 
Tsimenidis, 1984), feeding ecology (Lopez et al., 2016), 
morphometries (Negzaoui-Garali and Ben Salem, 2008), 
parasites (Colmenero et al., 2015a), and ova character- 
istics (Colmenero et al., 2015b). Among these studies, 
only Ungaro et al. (2002) analyzed some of the biologi- 
cal features of this species by using data available from 
trawl surveys, including data on distribution, abun- 
^ Tudo Vila, P. 2015. Unpubl. data. Directorate of Fishing 
and Maritime Affairs, Government of Catalonia, Avinguda 
Diagonal 523-525, 08029 Barcelona, Spain. 
^ Cardinale, M., D. Damalas, and C. G. Oslo (eds.). 2015. Sci- 
entific, Technical and Economic Committee for Fisheries 
(STECF) — Mediterranean Assessments, part 2 (STECF-15- 
06), 396 p. Publications Office of the European Union, Lux- 
embourg. [Available from website.] 
dance, stock demography, and size at maturity. The lat- 
ter work is valuable but is limited because sampling 
occurred only in the spring and summer; a whole year 
of sampling is recommended to obtain more accurate 
biological information. 
A study of reproductive ecology is important for an 
understanding of population dynamics, and it is critical 
for assessing the effects of harvesting on fish popula- 
tions when attempting to develop appropriate manage- 
ment strategies. Recruitment is recognized as a key 
process for maintaining sustainable populations, and 
the relationship between the reproductive output of the 
population and the resulting recruitment is central to 
understanding how a fish population will respond to 
constant stressors such as fishing (Chambers and Trip- 
pel, 1997). Although knowing more about the relation- 
ships between life history strategies and productivity 
with depth could help managers understand the poten- 
tial response of a deep-sea species to fishing (Brazen 
and Haedrich, 2012), it is first necessary to conduct 
biological studies of fish to gain knowledge of the re- 
productive system of a species (Koslow et al., 1995). 
Such studies include gonad morphology (external and 
cellular description of the ovary and testis), reproduc- 
tive pattern (hermaphroditism or gonochorism), repro- 
ductive behavior, reproductive cycle, spawning season 
duration, size at maturity, sex ratio, size at sexual 
transition, and fecundity. 
All of this information can be applied at the popu- 
lation level to evaluate reproductive potential and to 
serve as a basis for limits on fishing that aim in or- 
der to keep recruitment at sustainable levels (Garcfa- 
Diaz et ah, 2006). Because reproductive strategy varies 
within species, depending on the area of distribution of 
each species and the depth distribution of each species 
in each area (Rotllant et al., 2002), there is a need for 
knowledge about reproduction of deep-sea fish species. 
Such information is needed particularly in the Mediter- 
ranean Sea because the data available for this region 
are limited (Morales-Nin et al., 1996; D’Onghia et al., 
2008; Munoz et ah, 2010; Bustos-Salvador et al., 2015), 
and, furthermore, target species of fisheries have been 
the focus of only a few studies (Rotllant et ah, 2002; 
Recasens et al., 2008). 
The goal of this study was to describe the reproduc- 
tive parameters — gonadal morphology, spawning sea- 
son, size at sexual maturity, oocyte development, and 
fecundity — of white anglerfish in the northwestern 
Mediterranean Sea in order to provide valuable infor- 
mation and scientific background to improve stock as- 
sessments and effective management for Lophius spe- 
cies in Mediterranean waters. 
Materials and methods 
Sampling and data collection 
Between June 2007 and December 2010, 556 white 
anglerfish, with total lengths (TLs) of 9-120 cm, were 
