For ostracods described in Chapter 6, highest
densities were recorded in the regions of Cape
Froward, Baia Inutil and Paso Ancho which are
areas of high phytoplankton biomass and production (Guglielmo et al. 1993). In many samples, densities were greater than 100 ind m- 3 ,
with a maximum of > 600 ind m - 3 , mainly due to
the presence of one species, Discoconchoecia elegans. Much lower densities were recorded in the
Atlantic sector of the Straits, where one species,
Pseudoconchoecia serrulata, dominated over the
others, and in the Pacific area characterized by a
high species diversity.
Of the eight species of Halocyprida sampled
in the Straits, three (D. elegans, P. serrulata and
Obtusoecia antarctica) had already been recorded during the course of the Italian expedition in
the Southern Ocean in 1989-1990 (Benassi et al.
1992). In the case of two other species of Halocyprida (Loricoecia loricata and Paramollicia
rhynchena) and the myodocopide Macrocypridina poulseni, the present records are the first for
the region, representing the most southerly yet
for these species.
With regards to the biogeography of the Halocyprida sampled, four species (Mikroconchoecia
acuticosta, D. elegans, L. loricata and P. rhynchena) are transoceanic, reaching as far as 60°N; the
four other species (Metaconchoecia australis,
Conchoecilla chuni, P. serrulata and O. antarctica) are confined to the Southern Hemisphere.
The northernmost record of the myodocopide
M. poulseni is 37°N. Four other species are considered epibenthic (Philomedes eugeniae and P.
cubitum) or planto-benthic (Paradoxostoma sp.
aff. hypselum and P. magellanicum). Of these, P.
hypselum is circum-Antarctic in distribution,
whereas the others are typical of the Magellanic
region of the sub-Antarctic.
Chapter 7 describes the chaetognaths ofwhich
Sagitta tasmanica was by far the most common,
representing 75% of all specimens collected.
This percentagewas evenhigher (95 %) atthe Pacific entrance to the Straits. It was the only species sampled throughout the study are a. The four
other species were much less common: 5. decipiens (4.5 %), S. gazellae (0.8 %), 5. maxima (1 %)
and Eukrohnia hamata (12 %). The number of
specimens diminished from the Pacific to Atlantic entrances and only on the Pacific side of the
References
3
Straits were all species sampled. This was probably due to the deeper depths in this area allowing for strong diel vertical migrations. Only one
specimen each of S. decipiens and 5. gazellae was
sampled east of Ca pe Froward, at the entrance to
Baia Inutil and within the Bay, respectively. Several specimens were in very poor condition, but
their general shape suggests the probable presence of other very rare species such as Eukrohnia
bathypelagica, 5agitta marri and 5. planctonis.
References
Antezana T (1976) Diversidad y equilibrio ecol6gico en
communidades pehigicas. In: Orrego F ( ed) Preservaci6n del Medio Ambiente Marino. Inst Est Internac U
de Chile, Santiago, pp 40-54
Antezana T (1981) Zoogeography of euphausiids of the
South Eastern Pacific Ocean. Memorias del Seminario
sobre Indicadores Biol6gicos del Plancton. UNESCO,
Montevideo, pp 5-23
Antezana T, Brinton E (1981) Euphausiacea. In: Boltowskoy
D (ed) Atlas del zooplancton del Atlântico Sudoccidental. INIDEP, Buenos Aires, pp 681-698
Antezana T, Dellarossa V, Zufiiga A, Rosas A ( 1992) Features
of the pelagic environment of Chilean fjords. In: GaHardo VA, Ferretti O, Moyano HI (eds) Oceanografia in
Antartide. ENEA-PNR, Rome, pp 460-466
Artegiani A, Paschini E ( 1991) Hydrological characteristics
of the Straits of Magellan: austral summer 1990/91 (February-March). Mem Biol Mar Oceanogr 19: 77-81
Artegiani A, Paschini E, Andueza-Calder6n (1991) Physical
oceanography of the Straits of Magellan. Nat Se Corn
Ant, Magellan Cruise, February-March 1991, Data Rep I:
11--52
Balech E ( 1954) Divisi6n zoogeogrâfica de! litoral sudamericano. Rev Biol Mar Valparaîso 4: 184-195
Benassi G, Naldi M, Mckenzie KG (1992) Preliminary research on species distribution of planktonic ostracods
(Halocyprididae) in the Ross Sea, Antarctica. Crustacean Biol 12: 68-78
Brattstrom H, Johanssen A (1983) Ecologica! and regional
zoogeography of the marine benthic fauna of Chile. Report No 49 of the Lund University Chile Expedition
1948-1949. Sarsia 68:283-339
Briggs JC (1974) Marine zoogeography. McGraw-Hill, New
York, 475 pp
Brinton E (1962) The distribution of Pacific euphausiids.
Bull Scripps Inst Oceanogr 8: 51-270
Clement A, Guzmân L ( 1989) Red tides in Chilean fjords. In:
Okaichi T, Anderson DM, Nemoto T (eds) Red tides: biology, environmental science and toxicology. Elsevier,
NewYork,pp 121-124
Eckman S (1953) Zoogeography of the sea. Sidgwick and
Jackson, London, 417 pp
Guglielmo L, Antezana T, Costanzo G, Zagami G (1991)
Zooplankton communities in the Straits of Magellan.
Mem Biol Mar Oceanogr 19: 157-161
densities were recorded in the regions of Cape
Froward, Baia Inutil and Paso Ancho which are
areas of high phytoplankton biomass and production (Guglielmo et al. 1993). In many samples, densities were greater than 100 ind m- 3 ,
with a maximum of > 600 ind m - 3 , mainly due to
the presence of one species, Discoconchoecia elegans. Much lower densities were recorded in the
Atlantic sector of the Straits, where one species,
Pseudoconchoecia serrulata, dominated over the
others, and in the Pacific area characterized by a
high species diversity.
Of the eight species of Halocyprida sampled
in the Straits, three (D. elegans, P. serrulata and
Obtusoecia antarctica) had already been recorded during the course of the Italian expedition in
the Southern Ocean in 1989-1990 (Benassi et al.
1992). In the case of two other species of Halocyprida (Loricoecia loricata and Paramollicia
rhynchena) and the myodocopide Macrocypridina poulseni, the present records are the first for
the region, representing the most southerly yet
for these species.
With regards to the biogeography of the Halocyprida sampled, four species (Mikroconchoecia
acuticosta, D. elegans, L. loricata and P. rhynchena) are transoceanic, reaching as far as 60°N; the
four other species (Metaconchoecia australis,
Conchoecilla chuni, P. serrulata and O. antarctica) are confined to the Southern Hemisphere.
The northernmost record of the myodocopide
M. poulseni is 37°N. Four other species are considered epibenthic (Philomedes eugeniae and P.
cubitum) or planto-benthic (Paradoxostoma sp.
aff. hypselum and P. magellanicum). Of these, P.
hypselum is circum-Antarctic in distribution,
whereas the others are typical of the Magellanic
region of the sub-Antarctic.
Chapter 7 describes the chaetognaths ofwhich
Sagitta tasmanica was by far the most common,
representing 75% of all specimens collected.
This percentagewas evenhigher (95 %) atthe Pacific entrance to the Straits. It was the only species sampled throughout the study are a. The four
other species were much less common: 5. decipiens (4.5 %), S. gazellae (0.8 %), 5. maxima (1 %)
and Eukrohnia hamata (12 %). The number of
specimens diminished from the Pacific to Atlantic entrances and only on the Pacific side of the
References
3
Straits were all species sampled. This was probably due to the deeper depths in this area allowing for strong diel vertical migrations. Only one
specimen each of S. decipiens and 5. gazellae was
sampled east of Ca pe Froward, at the entrance to
Baia Inutil and within the Bay, respectively. Several specimens were in very poor condition, but
their general shape suggests the probable presence of other very rare species such as Eukrohnia
bathypelagica, 5agitta marri and 5. planctonis.
References
Antezana T (1976) Diversidad y equilibrio ecol6gico en
communidades pehigicas. In: Orrego F ( ed) Preservaci6n del Medio Ambiente Marino. Inst Est Internac U
de Chile, Santiago, pp 40-54
Antezana T (1981) Zoogeography of euphausiids of the
South Eastern Pacific Ocean. Memorias del Seminario
sobre Indicadores Biol6gicos del Plancton. UNESCO,
Montevideo, pp 5-23
Antezana T, Brinton E (1981) Euphausiacea. In: Boltowskoy
D (ed) Atlas del zooplancton del Atlântico Sudoccidental. INIDEP, Buenos Aires, pp 681-698
Antezana T, Dellarossa V, Zufiiga A, Rosas A ( 1992) Features
of the pelagic environment of Chilean fjords. In: GaHardo VA, Ferretti O, Moyano HI (eds) Oceanografia in
Antartide. ENEA-PNR, Rome, pp 460-466
Artegiani A, Paschini E ( 1991) Hydrological characteristics
of the Straits of Magellan: austral summer 1990/91 (February-March). Mem Biol Mar Oceanogr 19: 77-81
Artegiani A, Paschini E, Andueza-Calder6n (1991) Physical
oceanography of the Straits of Magellan. Nat Se Corn
Ant, Magellan Cruise, February-March 1991, Data Rep I:
11--52
Balech E ( 1954) Divisi6n zoogeogrâfica de! litoral sudamericano. Rev Biol Mar Valparaîso 4: 184-195
Benassi G, Naldi M, Mckenzie KG (1992) Preliminary research on species distribution of planktonic ostracods
(Halocyprididae) in the Ross Sea, Antarctica. Crustacean Biol 12: 68-78
Brattstrom H, Johanssen A (1983) Ecologica! and regional
zoogeography of the marine benthic fauna of Chile. Report No 49 of the Lund University Chile Expedition
1948-1949. Sarsia 68:283-339
Briggs JC (1974) Marine zoogeography. McGraw-Hill, New
York, 475 pp
Brinton E (1962) The distribution of Pacific euphausiids.
Bull Scripps Inst Oceanogr 8: 51-270
Clement A, Guzmân L ( 1989) Red tides in Chilean fjords. In:
Okaichi T, Anderson DM, Nemoto T (eds) Red tides: biology, environmental science and toxicology. Elsevier,
NewYork,pp 121-124
Eckman S (1953) Zoogeography of the sea. Sidgwick and
Jackson, London, 417 pp
Guglielmo L, Antezana T, Costanzo G, Zagami G (1991)
Zooplankton communities in the Straits of Magellan.
Mem Biol Mar Oceanogr 19: 157-161