filamentous cyanobacteria whereas species of the Order Aspidochirotida (I. badionotus, Holothuria grisea, H. occidentalis, H. pseudofossor and H. surinamensis)
consume detritus consisting of calcareous sand or quartz, coral fragments, bivalves
shells, test and spines fragments of echinoderms, sponge spicules, fish scales and
amorphous material. Holothuroids of the Order Apoda scrape the surrounding
ground with their feathered tentacles and consume mainly benthic diatoms and
remnants of green and brown algae (Martínez 1989, 1991a, b).
7.2.3 Reproduction
The biology and reproductive behavior of echinoderms in Venezuela is poorly
known. However, some studies suggest that temperature represents a key exogenous factor in the onset of gametogenesis. In the northeastern region of Venezuela,
hydrographic and nutrient availability in coastal water masses are variable due to
the upwelling phenomena, which promote temperature fluctuations mostly during
the first half of the year (with variations between 20 and 28 °C) (Ferraz-Reyes
1987). Montealegre and Gómez (2005) indicate that L. variegatus exhibits the
highest spawning activity in June and July in coincidence with an increase of water
temperature. Espinoza et al. (2008), in spite of not finding a clear influence
of environmental factors on the reproduction processes of E. lucunter and
L. variegatus, indicated that low temperature (23–24 °C) seems to be an initiating
factor of gametogenesis and high temperature (26–28 °C) of maturation of
gametes of L. variegatus.
Muñoz (1980), Muñoz and Ellietes (1982, 1983) and Brey (1992), evaluated the
effect of different toxic substances (ferrous sulphate and sodium hypochlorite), as
well as temperature on embryonic development, fertilization and reproductive
processes in E. lucunter. Furthermore, Muñoz (1980) evaluated the fertilization of
eggs under variable thermal conditions (25, 30, 35 and 40 °C), finding a greater
motility of spermatozoa at 30–35 °C, a reduction in the percent of fertilization at
40 °C and a moderate reduction in the number of fertilized eggs at 25 °C. Brey
(1992) studied the effect of the ratio sperm/eggs and the time of post-dilution of
sperm in sea water on the fertilization success. Toxicity assays with Cr
6+
(K 2 Cr 2 O 7 ), Zn
2+ (ZnCl 2 ) and Cu
2+ (CuSO 4 ) found that zinc and chromium are less
toxic than copper (LD50 for copper between 36.1 and 119.3 ppb).
One aspect that is gaining importance on the eastern coast of Venezuela is
knowledge about larval and juvenile development of echinoid species with
potential for aquaculture. Some species in this category are L. variegatus (Butriago
and Lodeiros 2005; Butriago et al. 2005; Gómez and Gómez 2005; Domínguez
et al. 2007), T. ventricosus (Fernández 2005) and A. punctulata (García et al.
2005), in which the effect of salinity and food type were evaluated and are discussed in Sect. 7.5 of this chapter.
In holothurians, Palazón (2001, 2010) studied the reproductive biology of
I. badionotus from the islands of Margarita, Coche and Cubagua, in northeastern
7 Echinoderms from Venezuela
243
consume detritus consisting of calcareous sand or quartz, coral fragments, bivalves
shells, test and spines fragments of echinoderms, sponge spicules, fish scales and
amorphous material. Holothuroids of the Order Apoda scrape the surrounding
ground with their feathered tentacles and consume mainly benthic diatoms and
remnants of green and brown algae (Martínez 1989, 1991a, b).
7.2.3 Reproduction
The biology and reproductive behavior of echinoderms in Venezuela is poorly
known. However, some studies suggest that temperature represents a key exogenous factor in the onset of gametogenesis. In the northeastern region of Venezuela,
hydrographic and nutrient availability in coastal water masses are variable due to
the upwelling phenomena, which promote temperature fluctuations mostly during
the first half of the year (with variations between 20 and 28 °C) (Ferraz-Reyes
1987). Montealegre and Gómez (2005) indicate that L. variegatus exhibits the
highest spawning activity in June and July in coincidence with an increase of water
temperature. Espinoza et al. (2008), in spite of not finding a clear influence
of environmental factors on the reproduction processes of E. lucunter and
L. variegatus, indicated that low temperature (23–24 °C) seems to be an initiating
factor of gametogenesis and high temperature (26–28 °C) of maturation of
gametes of L. variegatus.
Muñoz (1980), Muñoz and Ellietes (1982, 1983) and Brey (1992), evaluated the
effect of different toxic substances (ferrous sulphate and sodium hypochlorite), as
well as temperature on embryonic development, fertilization and reproductive
processes in E. lucunter. Furthermore, Muñoz (1980) evaluated the fertilization of
eggs under variable thermal conditions (25, 30, 35 and 40 °C), finding a greater
motility of spermatozoa at 30–35 °C, a reduction in the percent of fertilization at
40 °C and a moderate reduction in the number of fertilized eggs at 25 °C. Brey
(1992) studied the effect of the ratio sperm/eggs and the time of post-dilution of
sperm in sea water on the fertilization success. Toxicity assays with Cr
6+
(K 2 Cr 2 O 7 ), Zn
2+ (ZnCl 2 ) and Cu
2+ (CuSO 4 ) found that zinc and chromium are less
toxic than copper (LD50 for copper between 36.1 and 119.3 ppb).
One aspect that is gaining importance on the eastern coast of Venezuela is
knowledge about larval and juvenile development of echinoid species with
potential for aquaculture. Some species in this category are L. variegatus (Butriago
and Lodeiros 2005; Butriago et al. 2005; Gómez and Gómez 2005; Domínguez
et al. 2007), T. ventricosus (Fernández 2005) and A. punctulata (García et al.
2005), in which the effect of salinity and food type were evaluated and are discussed in Sect. 7.5 of this chapter.
In holothurians, Palazón (2001, 2010) studied the reproductive biology of
I. badionotus from the islands of Margarita, Coche and Cubagua, in northeastern
7 Echinoderms from Venezuela
243