2001). However, active management actions directed to control urchin population
have been limited to developing a strategy of manually removing sea urchin by
scuba divers, providing evidence that erect macroalgae have the potential to
recolonize encrusting macroalgae barrens (Brito et al. 2004), but of doubtful
outcome in the long-term. Combined perturbations caused by overfishing and
progressive sea water warming are likely to result in an environment increasingly
favourable to the sea urchin, which seems difficult to control with such small-scale
actions. Conservation policies need to focus efforts on specifically protecting
healthy macroalgal bed habitats and the predatory fishes within them, because they
are predicted to increase post-settlement mortality of D. africana. Such actions
could improve ecosystem function by retaining the equilibrium between sea
urchins and macroalgae.
15.5 Aquaculture and Fisheries
Pre-hispanic human settlement in the Canary Islands, commondly known as
Guanches (Majos-Lanzarote and Fuerteventura; Canarii-Gran Canaria; GuanchesTenerife; Benahoritas-La Palma; Bimbaches-El Hierro) usually consumed sea
urchins. Indications of pre-hispanic human consumption have been discovered in
various shells accumulations locations in the islands. However sea urchin species
have been identified only at the ‘‘Guinea deposit’’ in Frontera-El Hierro (Martín
Oval et al. 1985). The species most consumed was P. lividus, probably because of
its abundance in intertidal rocky areas. Nowadays, this sea urchin is still consumed
by the islanders. However it remains only in particular coastal areas as a tradition
and no commercial exploitation exists. Presently, and probably then, this sea
urchin is also used as fish bait for fishing traps or to attract fishes to hook lines. In
some coastal locations this is the only known use. Today, other sea urchin species,
such as Arbacia lixula, Diadema africana and Sphaerechinus granularis, are also
used as bait. Arbacia lixula and D. africana are collected by snorkeling while S.
granularis, due its deeper distribution, is a bycatch of trammel nets. The number of
urchins used for this purpose is not known and is very difficult to monitor due to
the diversity of discharging places, many of them located at inaccessible sites.
Paracentrotus lividus is commercially exploited in several European countries
such as Ireland, France, Portugal, Italy, Greece and Spain. In the Spanish Peninsula, it is mainly exploited in the northwest (Galicia), north (Cantabria, Asturias y
Pais Vasco), northeast (Cataluña), and in the south (Andalucía). Although, it is
locally consumed in all these Spanish Comunidades, France is the main consumer
of sea urchins in Europe and the second consumer in the world after Japan
(Grosjean 2001). At the present, some of the most important fisheries in Europe
like the ones in Ireland and Brittany have collapsed (Le Direach 1987; Andrew
et al. 2002). In Spain, fishing activities regulations depend on the ‘‘Comunidad
Autónoma’’. While Galicia has a well developed sustainable fishing activity
(Catoira-Gòmez 1992), others like Asturias, Cantabria and Andalucía have a
15 Echinoderms of the Canary Islands, Spain
499
have been limited to developing a strategy of manually removing sea urchin by
scuba divers, providing evidence that erect macroalgae have the potential to
recolonize encrusting macroalgae barrens (Brito et al. 2004), but of doubtful
outcome in the long-term. Combined perturbations caused by overfishing and
progressive sea water warming are likely to result in an environment increasingly
favourable to the sea urchin, which seems difficult to control with such small-scale
actions. Conservation policies need to focus efforts on specifically protecting
healthy macroalgal bed habitats and the predatory fishes within them, because they
are predicted to increase post-settlement mortality of D. africana. Such actions
could improve ecosystem function by retaining the equilibrium between sea
urchins and macroalgae.
15.5 Aquaculture and Fisheries
Pre-hispanic human settlement in the Canary Islands, commondly known as
Guanches (Majos-Lanzarote and Fuerteventura; Canarii-Gran Canaria; GuanchesTenerife; Benahoritas-La Palma; Bimbaches-El Hierro) usually consumed sea
urchins. Indications of pre-hispanic human consumption have been discovered in
various shells accumulations locations in the islands. However sea urchin species
have been identified only at the ‘‘Guinea deposit’’ in Frontera-El Hierro (Martín
Oval et al. 1985). The species most consumed was P. lividus, probably because of
its abundance in intertidal rocky areas. Nowadays, this sea urchin is still consumed
by the islanders. However it remains only in particular coastal areas as a tradition
and no commercial exploitation exists. Presently, and probably then, this sea
urchin is also used as fish bait for fishing traps or to attract fishes to hook lines. In
some coastal locations this is the only known use. Today, other sea urchin species,
such as Arbacia lixula, Diadema africana and Sphaerechinus granularis, are also
used as bait. Arbacia lixula and D. africana are collected by snorkeling while S.
granularis, due its deeper distribution, is a bycatch of trammel nets. The number of
urchins used for this purpose is not known and is very difficult to monitor due to
the diversity of discharging places, many of them located at inaccessible sites.
Paracentrotus lividus is commercially exploited in several European countries
such as Ireland, France, Portugal, Italy, Greece and Spain. In the Spanish Peninsula, it is mainly exploited in the northwest (Galicia), north (Cantabria, Asturias y
Pais Vasco), northeast (Cataluña), and in the south (Andalucía). Although, it is
locally consumed in all these Spanish Comunidades, France is the main consumer
of sea urchins in Europe and the second consumer in the world after Japan
(Grosjean 2001). At the present, some of the most important fisheries in Europe
like the ones in Ireland and Brittany have collapsed (Le Direach 1987; Andrew
et al. 2002). In Spain, fishing activities regulations depend on the ‘‘Comunidad
Autónoma’’. While Galicia has a well developed sustainable fishing activity
(Catoira-Gòmez 1992), others like Asturias, Cantabria and Andalucía have a
15 Echinoderms of the Canary Islands, Spain
499