The Cabo Frio Upwelling System, Brazil
103
nan des 1994). Their highest abundance below 18 oc suggests a close relationship with upwelling events. Benthic octopi (Semirossia tenera, Eledone
massyae ), which occur below 45 m depth, migrate towards the shore during
upwellings to feed and mate. They leave the shelf in late summer to spawn
in the deeper waters of the shelf break (Costa and Fernandes 1993a).
7.3.3 Nekton
High abundance of neritic squids, like Loligo sanpaulensis (74% of the
catch) and Loligo plei (13 %), is related to recruitment and to high productivity of feeding grounds. The arrival of Loligo sanpaulensis recruits coincides with coastal upwelling when cold nutrient-rich waters provide ample
food for juveniles (Costa and Fernandes 1993b ). Loligo sanpaulensis is one
of the upwelling's most important fisheries resources and highest catches
are associated with spring-summer upwelling at depths between 45 and
60m (Haimovici and Perez 1991).
The flow of SACW over the inner continental shelf influences the composition and abundance of benthic and demersal fishes (79 species; Netto
and Gaelzer 1991). Permanent components of the demersal community
are the flounder Etropus longimanus, the ray Zapterix brevirostris, the
sea robin Prionotus nudigula, the rough-scad Trachurus lathami, and the
flathead Percophis brasiliensis. Together with SACW, species typical of deep
habitats (i.e. the red porgy Pagrus pagrus, the cusk-eel Genypterus brasiliensis, the silver hake Merluccius hubbsi, the anglerfish Lophius gastrophysus) reach the coastal zone (30-60 m depth). Upwelling provides favorable
conditions for pelagic planktivorous fishes, such as the Brazilian sardine
(Sardinella brasiliensis) which supports one of the most important fisheries in the region. The survival of larvae depends on the intensity of
SACW intrusion during late spring and summer, thus a decline in catch
from 200,000 to 50,000 tons ( 1973-1993) may have been caused by recruitment failure of some year-classes, owing to low frequency of upwelling
events (Matsuura 1996). Other components of the pelagic fish fauna are the
skipjack (Katsuwonus pelamis), the frigate tuna (Auxis thazard), the Atlantic little tuna (Euthynnus alletteratus), the chub mackerel (Scomber japonicus), the Atlantic moonfish (Sele setapinnis), the blue runner ( Caranx
cryusos), the bluefish (Pomatomus saltator), and the dolphin (Coryphaena
hippurus). The abundance of nekton provides an important food source
for seabirds over the inner shelf. The brown booby Sula leucogaster and the
terns Sterna hiriundinacea and Sterna eurygnatha are top carnivores of
pelagic resources and Cabo Frio Island offers habitat for reproductive
colonies of numerous species of birds.
103
nan des 1994). Their highest abundance below 18 oc suggests a close relationship with upwelling events. Benthic octopi (Semirossia tenera, Eledone
massyae ), which occur below 45 m depth, migrate towards the shore during
upwellings to feed and mate. They leave the shelf in late summer to spawn
in the deeper waters of the shelf break (Costa and Fernandes 1993a).
7.3.3 Nekton
High abundance of neritic squids, like Loligo sanpaulensis (74% of the
catch) and Loligo plei (13 %), is related to recruitment and to high productivity of feeding grounds. The arrival of Loligo sanpaulensis recruits coincides with coastal upwelling when cold nutrient-rich waters provide ample
food for juveniles (Costa and Fernandes 1993b ). Loligo sanpaulensis is one
of the upwelling's most important fisheries resources and highest catches
are associated with spring-summer upwelling at depths between 45 and
60m (Haimovici and Perez 1991).
The flow of SACW over the inner continental shelf influences the composition and abundance of benthic and demersal fishes (79 species; Netto
and Gaelzer 1991). Permanent components of the demersal community
are the flounder Etropus longimanus, the ray Zapterix brevirostris, the
sea robin Prionotus nudigula, the rough-scad Trachurus lathami, and the
flathead Percophis brasiliensis. Together with SACW, species typical of deep
habitats (i.e. the red porgy Pagrus pagrus, the cusk-eel Genypterus brasiliensis, the silver hake Merluccius hubbsi, the anglerfish Lophius gastrophysus) reach the coastal zone (30-60 m depth). Upwelling provides favorable
conditions for pelagic planktivorous fishes, such as the Brazilian sardine
(Sardinella brasiliensis) which supports one of the most important fisheries in the region. The survival of larvae depends on the intensity of
SACW intrusion during late spring and summer, thus a decline in catch
from 200,000 to 50,000 tons ( 1973-1993) may have been caused by recruitment failure of some year-classes, owing to low frequency of upwelling
events (Matsuura 1996). Other components of the pelagic fish fauna are the
skipjack (Katsuwonus pelamis), the frigate tuna (Auxis thazard), the Atlantic little tuna (Euthynnus alletteratus), the chub mackerel (Scomber japonicus), the Atlantic moonfish (Sele setapinnis), the blue runner ( Caranx
cryusos), the bluefish (Pomatomus saltator), and the dolphin (Coryphaena
hippurus). The abundance of nekton provides an important food source
for seabirds over the inner shelf. The brown booby Sula leucogaster and the
terns Sterna hiriundinacea and Sterna eurygnatha are top carnivores of
pelagic resources and Cabo Frio Island offers habitat for reproductive
colonies of numerous species of birds.