coast of Ecuador was observed, in areas possibly linked to large populations of
brittle stars, and sea urchins, and sand dollars (larva echinopluteus larvae)
(Luzuriaga 2011). Luzuriaga (1993) and Luzuriaga et al. (2007) reported high
densities of pluteus larvae ([200 pluteus larvae m
-3 ) along the inner estuaries and
inland ecosystems of ‘‘Mataje-Cayapas’’ at Esmeraldas, at the mouth the rivers
Tambillo and Najurungo (Fig. 6.1), in August and December 1979 and November
2000 when there is a large influence of oceanic waters into estuaries. However,
few ophiopluteus larvae were reported in the open sea in October 2003, at the
south and north of the Ecuadorian coast, near the archipelago of Jambelí, El Oro,
and Punta Galera, Esmeraldas (Luzuriaga 2011). The higher concentrations of
ophiopluteus larva were documented in surface and vertical collections (using nets
with a mesh size of 200 and 300 lm) in October 2004, November 2005 and
February 2009 cruises near the southern coast of Ecuador, from Puntilla de Santa
Elena to the estuary of Gulf of Guayaquil and Jambelí Archipelago. This area is
greatly influenced by the Humboldt Current off the coast of Ecuador (Fig. 6.6 a–j).
Therefore the waters are rich in nutrients and plankton biomass that favor larval
echinoderm development (Coello and Prado 1999; Luzuriaga and Elías 1999).
6.3.4 Predation, Parasitism and Disease
Sea Cucumbers
Sonnenholzner and Molina (2005) provided information on the host–parasite
relationship that occurs along the southeastern and western bioregions of the
Galápagos Islands by examining two families of aspidochirote holothurians: (1)
Holothuridae: Holothuria portovallartensis (n = 1557) and H. theeli (n = 983),
and (2) Stichopodidae: Isostichopus fuscus (n = 850) and Stichopus horrens
(n = 150). Holothuria portovallartensis and H. theeli were infected by the same
gastropod parasite Balcis panamensis. The prevalence of infection was high, with
95 and 79 %, respectively. The maximum number of parasites (adult and juvenile)
in the same host was eight and six, respectively. Both I. fuscus (n = 850) and S.
horrens (n = 150) had a low frequency of parasitism by Melanella falcata.
Sand Dollars
Echinoderms are subject to predation by crabs, gastropods, lobsters, fish, and other
species, and their populations are affected by biotic diseases caused by a variety of
parasites and microorganisms (Jangoux 1990). In particular clypeasteroids are
preyed upon by gastropods that drill holes into the coelomic cavity, although the
attack is not always successful (Moore 1956; Gerace and Lyndsay 1992;
McClintock and Marion 1993). Disease symptoms of populations undergoing mass
mortalities include lesions and necrotic tissue of the body wall caused by vibrios
210
J. Sonnenholzner et al.
brittle stars, and sea urchins, and sand dollars (larva echinopluteus larvae)
(Luzuriaga 2011). Luzuriaga (1993) and Luzuriaga et al. (2007) reported high
densities of pluteus larvae ([200 pluteus larvae m
-3 ) along the inner estuaries and
inland ecosystems of ‘‘Mataje-Cayapas’’ at Esmeraldas, at the mouth the rivers
Tambillo and Najurungo (Fig. 6.1), in August and December 1979 and November
2000 when there is a large influence of oceanic waters into estuaries. However,
few ophiopluteus larvae were reported in the open sea in October 2003, at the
south and north of the Ecuadorian coast, near the archipelago of Jambelí, El Oro,
and Punta Galera, Esmeraldas (Luzuriaga 2011). The higher concentrations of
ophiopluteus larva were documented in surface and vertical collections (using nets
with a mesh size of 200 and 300 lm) in October 2004, November 2005 and
February 2009 cruises near the southern coast of Ecuador, from Puntilla de Santa
Elena to the estuary of Gulf of Guayaquil and Jambelí Archipelago. This area is
greatly influenced by the Humboldt Current off the coast of Ecuador (Fig. 6.6 a–j).
Therefore the waters are rich in nutrients and plankton biomass that favor larval
echinoderm development (Coello and Prado 1999; Luzuriaga and Elías 1999).
6.3.4 Predation, Parasitism and Disease
Sea Cucumbers
Sonnenholzner and Molina (2005) provided information on the host–parasite
relationship that occurs along the southeastern and western bioregions of the
Galápagos Islands by examining two families of aspidochirote holothurians: (1)
Holothuridae: Holothuria portovallartensis (n = 1557) and H. theeli (n = 983),
and (2) Stichopodidae: Isostichopus fuscus (n = 850) and Stichopus horrens
(n = 150). Holothuria portovallartensis and H. theeli were infected by the same
gastropod parasite Balcis panamensis. The prevalence of infection was high, with
95 and 79 %, respectively. The maximum number of parasites (adult and juvenile)
in the same host was eight and six, respectively. Both I. fuscus (n = 850) and S.
horrens (n = 150) had a low frequency of parasitism by Melanella falcata.
Sand Dollars
Echinoderms are subject to predation by crabs, gastropods, lobsters, fish, and other
species, and their populations are affected by biotic diseases caused by a variety of
parasites and microorganisms (Jangoux 1990). In particular clypeasteroids are
preyed upon by gastropods that drill holes into the coelomic cavity, although the
attack is not always successful (Moore 1956; Gerace and Lyndsay 1992;
McClintock and Marion 1993). Disease symptoms of populations undergoing mass
mortalities include lesions and necrotic tissue of the body wall caused by vibrios
210
J. Sonnenholzner et al.