The Estuary Ecosystem of Buenaventura Bay, Colombia
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18.3.5 Pelagic Estuarine Environment
Organisms which live in the water column of Buenaventura Bay have to
tolerate brackish and turbid conditions. Phytoplankton is dominated by
high numbers of diatoms (Thalassiosira sp., Biddulphia spp., Rhizosolenia
spp., Chaetoceros spp., Nitzchia spp., Thalassiotrix mediterranea, T. frauenfeldii, Thalassionema spp., Coscinodiscus gigas, C. kurzii). Dinoflagellates are scarce and restricted to the mouth of the bay, while volvocaceans
frequently occur in polluted areas. Zooplankton diversity is high, owing to
the large number of larvae (meroplankton) of species which spend their
early life stages in estuarine waters, as well as the presence of holoplankton
which is largely composed of copepods, arrowworms ( Chaetognatha),
medusae, and tintinids.
About 185 fish species of 50 families compose the nekton community
(Rubio 1984), though marine fishes and shellfishes are generally present as
larvae and juveniles. Scianidae is the most diverse family (25 species);
however, families like Carangidae (15), Engraulidae (11), Clupeidae (9),
Pomadasydae (8), Gobiidae (7), Ariidae (6), and Centropomidae (5) are
also important. The herring Lile stolifera is the most abundant species,
other representative species are pufferfish (Sphoeroides annulatus), anchovies (Anchoa panamensis, A. spinifer), mullet (Mugil cephalus), soapfish (Dormitator latifrons), mackerel ( Chloroscombrus orqueta), herring
(Opisthonema libertate), halfbeaks (Hyporhamphus unifasciatus), and sitversicles (i.e. Melaniris pachylepis). Invertebrates are poorly represented in
the waters of the bay, prawns (Penaeidae and Palaemonidae) being most
important, and crabs (Portunidae and Calappidae) and squids (Loligunculla) are frequent at the mouth of the bay. Typical estuarine fishes which
reproduce and feed in the bay do not migrate upstream into freshwater
areas or out of the bay into the ocean. Freshwater organisms do not migrate
beyond the oligohaline zones of the river mouths and therefore are generally absent from Buenaventura Bay waters.
18.4 Trophic Relations
18.4.1 Primary Production
The different biological communities and habitats and the complex estuarine conditions in Buenaventura Bay provide for a diverse and productive
ecosystem. The high nutrient concentrations at the mouth of creeks and
273
18.3.5 Pelagic Estuarine Environment
Organisms which live in the water column of Buenaventura Bay have to
tolerate brackish and turbid conditions. Phytoplankton is dominated by
high numbers of diatoms (Thalassiosira sp., Biddulphia spp., Rhizosolenia
spp., Chaetoceros spp., Nitzchia spp., Thalassiotrix mediterranea, T. frauenfeldii, Thalassionema spp., Coscinodiscus gigas, C. kurzii). Dinoflagellates are scarce and restricted to the mouth of the bay, while volvocaceans
frequently occur in polluted areas. Zooplankton diversity is high, owing to
the large number of larvae (meroplankton) of species which spend their
early life stages in estuarine waters, as well as the presence of holoplankton
which is largely composed of copepods, arrowworms ( Chaetognatha),
medusae, and tintinids.
About 185 fish species of 50 families compose the nekton community
(Rubio 1984), though marine fishes and shellfishes are generally present as
larvae and juveniles. Scianidae is the most diverse family (25 species);
however, families like Carangidae (15), Engraulidae (11), Clupeidae (9),
Pomadasydae (8), Gobiidae (7), Ariidae (6), and Centropomidae (5) are
also important. The herring Lile stolifera is the most abundant species,
other representative species are pufferfish (Sphoeroides annulatus), anchovies (Anchoa panamensis, A. spinifer), mullet (Mugil cephalus), soapfish (Dormitator latifrons), mackerel ( Chloroscombrus orqueta), herring
(Opisthonema libertate), halfbeaks (Hyporhamphus unifasciatus), and sitversicles (i.e. Melaniris pachylepis). Invertebrates are poorly represented in
the waters of the bay, prawns (Penaeidae and Palaemonidae) being most
important, and crabs (Portunidae and Calappidae) and squids (Loligunculla) are frequent at the mouth of the bay. Typical estuarine fishes which
reproduce and feed in the bay do not migrate upstream into freshwater
areas or out of the bay into the ocean. Freshwater organisms do not migrate
beyond the oligohaline zones of the river mouths and therefore are generally absent from Buenaventura Bay waters.
18.4 Trophic Relations
18.4.1 Primary Production
The different biological communities and habitats and the complex estuarine conditions in Buenaventura Bay provide for a diverse and productive
ecosystem. The high nutrient concentrations at the mouth of creeks and