206
A. Granata et al.
Tyrrhenian Sea confirm the data found in the literature with regard to other species and geographical locations. There is substantial evidence
of a return of energy to the upper layers of the
ocean, with cephalopods forming a rather large
component of the diet of tunas (40%) and preying
on mesopelagic fishes to a conspicuous degree,
thus restoring a portion of the energy that is taken
from the surface levels.
The question of energy flow is not as simple
as depicted in this schematic outline. There are a
several unsolved problems: the low variability of
prey species depending perhaps on the ability of
the prey to avoid capture using the mechanism
of bioluminescence of prey fishes (Baguet et aL,
1983) or escaping from the predator by sudden
darting movements (Mann 1984). Alternatively,
the diet may be composed only of those species
characterized by high biomass, and in which
there is a lack of the most common species in the
diet. For example. Todarodes sagittatus,
Myctophum punctatum and Hygophum benoiti
have a low percentage occurrence (0.4%) even
though they are very abundant in this sea (Scotto
di Carlo et al. 1982). These species may migrate
to surface levels at night. These authors stated
that T. sagittatus feeds at night and not in strictly surface layers supporting the greater importance in the diet of the squid Maurolicus muelleri
and Argyropelecus hemigymnus (percentage
occurrence of 3.2 and 1.8%, respectively. Table
1). Both are non-migratory species, the former
remaining near the bottom (400-450 m in the
southern Tyrrhenian Sea; Genovese et al. 1985)
and the latter in the mesopelagic zone (300-600
m; Goodyear et aL 1972). Therefore, T. sagittatus
should be considered a good vehicle of energy
transfer from the zone ranging from sub-surface
layers down to the bottom (I00-800 m).
Nevertheless, its diet lacks the mesopelagic
species that populate the surface level (0-100 m)
at night and which are responsible for the subtra<;:tion of energy from the euphotic zone.
This review raises questions concerning the
complex trophic organization of the epi - and
mesopelagic zones and the flow of energy
between the different vertical trophic levels of
the oceans. In other words, for a study like this,
thorough investigations of the unresolved questions listed above are necessary. Moreover, the
hypothesis of a trophic chain composed of
cephalopods, mesopelagic fishes and crustaceans, with cephalopods acting as the connection between the surface and mesopelagic trophic chains, seems plausible.
References
Akimushkin II (1963) Cephalopods of the seas of the UMS. In:
Izdat Akad Nauk SSSR Moskva (Translated 1965 by Israel
Progr Sci Trans!) IPST 1384
Baguet F, Piccard J, Christophe B, Marechal G (1983)
Bioluminescence and luminescent fish in the Straits of
Messina from the mesoscaph "Forel". Mar BioI 74: 221-229
Berdar A, Costanzo G, Guglielmo L, lanora A, Scotto di Carlo B
(1979) Some aspects of the feeding habits of two species of
midwater fishes stranded along shores of the Straits of
Messfua. Rapp P-v Reun Comm Int Explor Sci Mer Mediterr
25/26: 209-210
Breiby A, ]obling M, Sundet JH (1984) Feeding habits ot the squid
Tadarodes sagittatus in north Norwegian waters. SCR Doc
NW Ad Fish Org 84100103: 11-99
Dalpadado P, Gjl'lsreter J (1988) Feeding ecology of the lanternfish
Benthosema pterotum from the Indian Ocean. Mar Bioi 99:
555-567
Farquhar GB (1977) Biological sound scattering in the oceans: a
review. In: Andersen NR, Zahuranec BJ (eds) Oceanic sound
scattering prediction. Plenum Press, New York, pp 493-527
Fields GW (1965) The structure, development, food relations,
reproduction and life history of the squid Loligo opalescens,
Berry. Fish Bull 131: 1-108
Genovese S, Berdar A, Guglielmo L (1971) Spiaggiamenti di fauna
abissale nello Stretto di Messina. Atti Soc Peloritana 17: 331370
Genovese S. Guglielmo L, !anora A, Scotto Di Carlo B (1985)
Osservazioni biologiche can il mesoscafo "Forel" nella
Stretto di Messina. Arch Oceanogr Limno120: 1-30
Goodyear RH, Zahuranec BT, Pugh WL, Gibbs RH (1972) Ecology
and vertical distribution of mediterranean midwater fishes.
In: Smits Inst Was Mediterr BioI Stud Final Rep 1: 91-229
Gorelova TA (1974) Zooplankton from the stomach of juvenile
lantern fish of the family Myctophidae. Okeanologiya 14:
575-580
Guglielmo L, Arena G, Granata A, Sidoti 0, Bonanzinga V, Sorad P
(1996) Distribuzione verticale e migrazione giornaliera
dello zooplancton e del micronecton nel Tirreno meridionale (lsole Eolie). Caratterizzazione ambientale marina del
sistema EoHe e dei baeini limitrofi di Cefalu e Gioiosa
(EOCUMM 95) In: Faranda FM, Povero P (eds) Data Rep,
Genova, pp 217-246
Guglielmo L, Zagami G (1985) Role of Euphausiids in DSL of
western Mediterranean Sea. Mem BioI Mar Ocean 15: 191206
Guglielmo L. Zagami G, Sidoti 0, Granata A (1995) Distribuzione
e migrazione giornaliera dello zooplancton nel Tirreno
meridionale (Isole Eolie): caratterizzazione ambientale
marina del sistema Eolie e dei bacini limitrofi ill Cefalu e
Gioiosa (BOCUMM 94) In: Faranda PM (ed) Data Rep,
Genova, pp 167-190
Holton AA (1969) Feeding behaviour of a vertically migrating
lanternfish. Pac Sd 23: 325-331
Hopkins TL, Baird RC (1985) Feeding ecology of four hatchetfishes (Sternoptychidae) in the Eastern Gulf of Mexico. Bull Mar
Sci 36: 260-277
Kinzer J, Schulz K (1985) Vertical distribution and feeding patterns of midwater fish in the central equatorial Atlantic. I.
Myctophidae. Mar Bioi 85: 313-322
Kinzer J, Schulz K (1988) Vertical distribution and feeding pat-
A. Granata et al.
Tyrrhenian Sea confirm the data found in the literature with regard to other species and geographical locations. There is substantial evidence
of a return of energy to the upper layers of the
ocean, with cephalopods forming a rather large
component of the diet of tunas (40%) and preying
on mesopelagic fishes to a conspicuous degree,
thus restoring a portion of the energy that is taken
from the surface levels.
The question of energy flow is not as simple
as depicted in this schematic outline. There are a
several unsolved problems: the low variability of
prey species depending perhaps on the ability of
the prey to avoid capture using the mechanism
of bioluminescence of prey fishes (Baguet et aL,
1983) or escaping from the predator by sudden
darting movements (Mann 1984). Alternatively,
the diet may be composed only of those species
characterized by high biomass, and in which
there is a lack of the most common species in the
diet. For example. Todarodes sagittatus,
Myctophum punctatum and Hygophum benoiti
have a low percentage occurrence (0.4%) even
though they are very abundant in this sea (Scotto
di Carlo et al. 1982). These species may migrate
to surface levels at night. These authors stated
that T. sagittatus feeds at night and not in strictly surface layers supporting the greater importance in the diet of the squid Maurolicus muelleri
and Argyropelecus hemigymnus (percentage
occurrence of 3.2 and 1.8%, respectively. Table
1). Both are non-migratory species, the former
remaining near the bottom (400-450 m in the
southern Tyrrhenian Sea; Genovese et al. 1985)
and the latter in the mesopelagic zone (300-600
m; Goodyear et aL 1972). Therefore, T. sagittatus
should be considered a good vehicle of energy
transfer from the zone ranging from sub-surface
layers down to the bottom (I00-800 m).
Nevertheless, its diet lacks the mesopelagic
species that populate the surface level (0-100 m)
at night and which are responsible for the subtra<;:tion of energy from the euphotic zone.
This review raises questions concerning the
complex trophic organization of the epi - and
mesopelagic zones and the flow of energy
between the different vertical trophic levels of
the oceans. In other words, for a study like this,
thorough investigations of the unresolved questions listed above are necessary. Moreover, the
hypothesis of a trophic chain composed of
cephalopods, mesopelagic fishes and crustaceans, with cephalopods acting as the connection between the surface and mesopelagic trophic chains, seems plausible.
References
Akimushkin II (1963) Cephalopods of the seas of the UMS. In:
Izdat Akad Nauk SSSR Moskva (Translated 1965 by Israel
Progr Sci Trans!) IPST 1384
Baguet F, Piccard J, Christophe B, Marechal G (1983)
Bioluminescence and luminescent fish in the Straits of
Messina from the mesoscaph "Forel". Mar BioI 74: 221-229
Berdar A, Costanzo G, Guglielmo L, lanora A, Scotto di Carlo B
(1979) Some aspects of the feeding habits of two species of
midwater fishes stranded along shores of the Straits of
Messfua. Rapp P-v Reun Comm Int Explor Sci Mer Mediterr
25/26: 209-210
Breiby A, ]obling M, Sundet JH (1984) Feeding habits ot the squid
Tadarodes sagittatus in north Norwegian waters. SCR Doc
NW Ad Fish Org 84100103: 11-99
Dalpadado P, Gjl'lsreter J (1988) Feeding ecology of the lanternfish
Benthosema pterotum from the Indian Ocean. Mar Bioi 99:
555-567
Farquhar GB (1977) Biological sound scattering in the oceans: a
review. In: Andersen NR, Zahuranec BJ (eds) Oceanic sound
scattering prediction. Plenum Press, New York, pp 493-527
Fields GW (1965) The structure, development, food relations,
reproduction and life history of the squid Loligo opalescens,
Berry. Fish Bull 131: 1-108
Genovese S, Berdar A, Guglielmo L (1971) Spiaggiamenti di fauna
abissale nello Stretto di Messina. Atti Soc Peloritana 17: 331370
Genovese S. Guglielmo L, !anora A, Scotto Di Carlo B (1985)
Osservazioni biologiche can il mesoscafo "Forel" nella
Stretto di Messina. Arch Oceanogr Limno120: 1-30
Goodyear RH, Zahuranec BT, Pugh WL, Gibbs RH (1972) Ecology
and vertical distribution of mediterranean midwater fishes.
In: Smits Inst Was Mediterr BioI Stud Final Rep 1: 91-229
Gorelova TA (1974) Zooplankton from the stomach of juvenile
lantern fish of the family Myctophidae. Okeanologiya 14:
575-580
Guglielmo L, Arena G, Granata A, Sidoti 0, Bonanzinga V, Sorad P
(1996) Distribuzione verticale e migrazione giornaliera
dello zooplancton e del micronecton nel Tirreno meridionale (lsole Eolie). Caratterizzazione ambientale marina del
sistema EoHe e dei baeini limitrofi di Cefalu e Gioiosa
(EOCUMM 95) In: Faranda FM, Povero P (eds) Data Rep,
Genova, pp 217-246
Guglielmo L, Zagami G (1985) Role of Euphausiids in DSL of
western Mediterranean Sea. Mem BioI Mar Ocean 15: 191206
Guglielmo L. Zagami G, Sidoti 0, Granata A (1995) Distribuzione
e migrazione giornaliera dello zooplancton nel Tirreno
meridionale (Isole Eolie): caratterizzazione ambientale
marina del sistema Eolie e dei bacini limitrofi ill Cefalu e
Gioiosa (BOCUMM 94) In: Faranda PM (ed) Data Rep,
Genova, pp 167-190
Holton AA (1969) Feeding behaviour of a vertically migrating
lanternfish. Pac Sd 23: 325-331
Hopkins TL, Baird RC (1985) Feeding ecology of four hatchetfishes (Sternoptychidae) in the Eastern Gulf of Mexico. Bull Mar
Sci 36: 260-277
Kinzer J, Schulz K (1985) Vertical distribution and feeding patterns of midwater fish in the central equatorial Atlantic. I.
Myctophidae. Mar Bioi 85: 313-322
Kinzer J, Schulz K (1988) Vertical distribution and feeding pat-