Pliocene, resulted in the extinction and renovation of different invertebrate faunas
(Jackson et al. 1993; Cheetham and Jackson 1996; O’Dea et al. 2007; Johnson
et al. 2009; Aguilera et al. 2010).
Paleontological records are lacking for the upper Cretaceous, Paleocene and
lower and middle Eocene. This bias could probably be associated to sampling
problems or underdevelopment of taxonomic work in the units of these eras which
have fragmentary remnants of echinoderms without a posterior classification (e.g.
Navay Formation of upper Cretaceous: Sánchez and Lorente 1977; Morán Formation of Paleocene: Bushman 1965; Misoa Formation of lower and medium
Eocene: Miller and Collinson 1951).
There is a clear preferential bathymetric distribution of recent echinoderms in
the western tropical Atlantic and Caribbean Sea (Lessios 2005; Francisco and
Pauls 2008). Families like Echinometridae, Clypeasteridae, Mellitidae and
Toxopneustidae are found with greater frequency in littoral zones of shallow
waters down to a depth of 402 m. This is in extreme contrast to families like
Echinothuriidae, Aspidodiadematidae, Pedinidae, Hemiasteridae, Pourtalesiidae,
Urechinidae, Aeropsidae and Lovenidae whose preferential depth is between 740
and 5,200 m. Amongst these extremes, the families Schizasteridae, Cidaridae and
Diadematidae are distributed with some variation on the platform and continental
slope. This fact shows the usefulness of echinoderms as indicators of paleoenvironments, as suggested by Kroh and Nebelsick (2003) and Mihaljevic ´ et al. (2010).
This agrees with the environment of sedimentation of the formations which hold
the co-generic taxa shown in the results described before. In the case of extinct
species whose habitat is unknown, it is necessary to use the faunistic associations
and lithology of the sediment types to support any paleobathymetric hypotheses.
7.5 Extraction, Fishing and Aquaculture
Fisheries of echinoderms are centered on sea urchin and sea cucumbers. They
represent a product of high cost, since sea urchin gonads and the body wall of sea
cucumbers (bêche-de-mer) are considered delicacies and aphrodisiacs.
Consumption of sea urchin gonads is primarily centered in Europe and Asia.
Consumption of sea cucumber body walls is primarily found in Asia and the
southwest Pacific.
It is currently considered that most sea urchin and sea cucumber fisheries have
reached their maximum exploitation rates. In contrast, their aquaculture is in
expansion, particularly that of the sea cucumber Apostichopus japonicus. FAO
statistics (http://www.fao.org/corp/statistics/en/) show that echinoderm extraction
has decreased from 140,000 t at the end of 1990s to 90,000 t in 2007, mainly due to
a reduction of catches because of overexploitation of natural stocks. However,
their cultivation, practically nonexistent in the twentieth Century, started in 2003
with a production of 37,000 t and reached 85,000 t in 2007, for a value of US$ 300
7 Echinoderms from Venezuela
257
(Jackson et al. 1993; Cheetham and Jackson 1996; O’Dea et al. 2007; Johnson
et al. 2009; Aguilera et al. 2010).
Paleontological records are lacking for the upper Cretaceous, Paleocene and
lower and middle Eocene. This bias could probably be associated to sampling
problems or underdevelopment of taxonomic work in the units of these eras which
have fragmentary remnants of echinoderms without a posterior classification (e.g.
Navay Formation of upper Cretaceous: Sánchez and Lorente 1977; Morán Formation of Paleocene: Bushman 1965; Misoa Formation of lower and medium
Eocene: Miller and Collinson 1951).
There is a clear preferential bathymetric distribution of recent echinoderms in
the western tropical Atlantic and Caribbean Sea (Lessios 2005; Francisco and
Pauls 2008). Families like Echinometridae, Clypeasteridae, Mellitidae and
Toxopneustidae are found with greater frequency in littoral zones of shallow
waters down to a depth of 402 m. This is in extreme contrast to families like
Echinothuriidae, Aspidodiadematidae, Pedinidae, Hemiasteridae, Pourtalesiidae,
Urechinidae, Aeropsidae and Lovenidae whose preferential depth is between 740
and 5,200 m. Amongst these extremes, the families Schizasteridae, Cidaridae and
Diadematidae are distributed with some variation on the platform and continental
slope. This fact shows the usefulness of echinoderms as indicators of paleoenvironments, as suggested by Kroh and Nebelsick (2003) and Mihaljevic ´ et al. (2010).
This agrees with the environment of sedimentation of the formations which hold
the co-generic taxa shown in the results described before. In the case of extinct
species whose habitat is unknown, it is necessary to use the faunistic associations
and lithology of the sediment types to support any paleobathymetric hypotheses.
7.5 Extraction, Fishing and Aquaculture
Fisheries of echinoderms are centered on sea urchin and sea cucumbers. They
represent a product of high cost, since sea urchin gonads and the body wall of sea
cucumbers (bêche-de-mer) are considered delicacies and aphrodisiacs.
Consumption of sea urchin gonads is primarily centered in Europe and Asia.
Consumption of sea cucumber body walls is primarily found in Asia and the
southwest Pacific.
It is currently considered that most sea urchin and sea cucumber fisheries have
reached their maximum exploitation rates. In contrast, their aquaculture is in
expansion, particularly that of the sea cucumber Apostichopus japonicus. FAO
statistics (http://www.fao.org/corp/statistics/en/) show that echinoderm extraction
has decreased from 140,000 t at the end of 1990s to 90,000 t in 2007, mainly due to
a reduction of catches because of overexploitation of natural stocks. However,
their cultivation, practically nonexistent in the twentieth Century, started in 2003
with a production of 37,000 t and reached 85,000 t in 2007, for a value of US$ 300
7 Echinoderms from Venezuela
257