unit taken incidentally in addition to the target species towards which fishing effort is
directed. Some or all of it may be returned to the sea as discards, usually dead or
dying.” The GFCM includes incidental catch of vulnerable species as a subset of
bycatch, which includes species such as marine mammals, sea turtles, seabirds, and
some elasmobranchs (FAO 2018).
In general, the main reason for discarding is the lack of commercial value of some
caught species (Kelleher 2005), although it also sometimes occurs because the fish
do not reach the minimum landing size, because catch quotas have been exceeded or
because the fish are damaged. The incidence of discards in species with commercial
interest is low, although part of the commercial catch may also be discarded to
comply with fishing regulations (Uhlmann et al. 2014). It is estimated that 7.3
million tons of fish (usually dead or dying) are discarded annually by marine
fisheries throughout the world, with the proportion of the catch discarded at sea
estimated at 8% t (Kelleher 2005). In the Mediterranean a rough estimation of
discards around 230,000 t, or 18.6% (13.3–26.8%) of the catch is produced
(Tsagarakis et al. 2014).
In order to tackle the problem of discards in European fisheries, the new Common
Fisheries Policy (CFP) (European Parlamient and Council Regulation (EU) 1380/
2013), establishes as a conservation measure the monitoring and reduction of
incidental catches and discards. This measure is part of the concept known as
“ecosystem approach,” which considers fisheries not only as a relationship between
the resource and the fleet but also considers the ecosystem that hosts the resource and
the socioeconomic scope of the fleet (Bellido et al. 2014). The new regulation
establishes the obligation to land catches of stocks subject to minimum sizes,
which is considered one of the easiest management instruments to apply and is
established with the aim of discouraging the capture of juveniles, since although this
type of regulation has influenced the sizes of the species landed, it has not done so in
the sizes of the species caught, which leads to their subsequent discarding (Catchpole
et al. 2005).
Under the Commission Delegated Regulation (EU) 2017/86 establishing a discard plan for certain demersal fisheries in the Mediterranean Sea, all catches of
species subject to catch limits and catches of species subject to minimum sizes must
be landed. An exemption from the landing obligation applies to bivalve mollusk
scallops (Pecten jacobaeus), clams (Venerupis spp. and Venus spp.) in the Western
Mediterranean Sea, as high survival rates can occur, taking into account the characteristics of fishing gears and practices and the ecosystem. This regulation provides
for “de minimis” exemptions affecting demersal fisheries in the Alboran Sea.
According to these exemptions, hake (Merluccius merluccius) and red mullet
(Mullus spp.) may be discarded up to a maximum of 7% in 2017 and 2018 and
6% in 2019 of the total annual catch of these species by trawlers and 1% of the total
annual catch of these species by vessels using gillnets.
In the Alboran Sea, demersal fisheries are multi-species, and it is very difficult to
identify target species, which influences the level and diversity of discards generated
(Eliasen and Christensen 2012) (Fig. 18.31). According to García et al. (2015) in the
618
M. González Aguilar et al.
directed. Some or all of it may be returned to the sea as discards, usually dead or
dying.” The GFCM includes incidental catch of vulnerable species as a subset of
bycatch, which includes species such as marine mammals, sea turtles, seabirds, and
some elasmobranchs (FAO 2018).
In general, the main reason for discarding is the lack of commercial value of some
caught species (Kelleher 2005), although it also sometimes occurs because the fish
do not reach the minimum landing size, because catch quotas have been exceeded or
because the fish are damaged. The incidence of discards in species with commercial
interest is low, although part of the commercial catch may also be discarded to
comply with fishing regulations (Uhlmann et al. 2014). It is estimated that 7.3
million tons of fish (usually dead or dying) are discarded annually by marine
fisheries throughout the world, with the proportion of the catch discarded at sea
estimated at 8% t (Kelleher 2005). In the Mediterranean a rough estimation of
discards around 230,000 t, or 18.6% (13.3–26.8%) of the catch is produced
(Tsagarakis et al. 2014).
In order to tackle the problem of discards in European fisheries, the new Common
Fisheries Policy (CFP) (European Parlamient and Council Regulation (EU) 1380/
2013), establishes as a conservation measure the monitoring and reduction of
incidental catches and discards. This measure is part of the concept known as
“ecosystem approach,” which considers fisheries not only as a relationship between
the resource and the fleet but also considers the ecosystem that hosts the resource and
the socioeconomic scope of the fleet (Bellido et al. 2014). The new regulation
establishes the obligation to land catches of stocks subject to minimum sizes,
which is considered one of the easiest management instruments to apply and is
established with the aim of discouraging the capture of juveniles, since although this
type of regulation has influenced the sizes of the species landed, it has not done so in
the sizes of the species caught, which leads to their subsequent discarding (Catchpole
et al. 2005).
Under the Commission Delegated Regulation (EU) 2017/86 establishing a discard plan for certain demersal fisheries in the Mediterranean Sea, all catches of
species subject to catch limits and catches of species subject to minimum sizes must
be landed. An exemption from the landing obligation applies to bivalve mollusk
scallops (Pecten jacobaeus), clams (Venerupis spp. and Venus spp.) in the Western
Mediterranean Sea, as high survival rates can occur, taking into account the characteristics of fishing gears and practices and the ecosystem. This regulation provides
for “de minimis” exemptions affecting demersal fisheries in the Alboran Sea.
According to these exemptions, hake (Merluccius merluccius) and red mullet
(Mullus spp.) may be discarded up to a maximum of 7% in 2017 and 2018 and
6% in 2019 of the total annual catch of these species by trawlers and 1% of the total
annual catch of these species by vessels using gillnets.
In the Alboran Sea, demersal fisheries are multi-species, and it is very difficult to
identify target species, which influences the level and diversity of discards generated
(Eliasen and Christensen 2012) (Fig. 18.31). According to García et al. (2015) in the
618
M. González Aguilar et al.