CHAPTER 19
Relationship between Fish Larval Biomass and Plankton Production
in the South Tyrrhenian Sea
R. Bruno, A. Granata, A. Cefali, L. Guglielmo, G. Brancato, and P. Barbera
ABSTRACT
Fish larval biomass was compared with plankton abundance and production in the coastal
south Tyrrhenian Sea from November 1994 to October 1995. Sardina pilchardus was the most
representative species in biomass, followed by Gymnammodytes cicerellus. S. pilchardus showed
a larger spawning period (January to May) together with Engraulis encrasico/us (July to
November). Ichthyoplankton standing stocks peaked in February (6.28 gm- 2 ), preceeding both
the first primary production peak and the spring maximum zooplankton biomass in May. The
results demonstrate that no temporal overlapping occurred among fish larval species in the
coastal waters of the southern Tyrrhenian Sea.
Introduction
Our understanding of the structure and dynamics of coastal marine food webs has progressed
considerably in recent years. Cushing (1967,
1969) assumed that the spawning period of the
pelagic fishes was fixed and did not change with
environmental conditions. On the contrary, we
now know that the timing of spawning and successfulllarval fish recruitment are strongly related to plankton production and zooplankton
species composition (Sameoto 1982; Fortier
1995; Mousseau et al. 1998). This has also been
demonstrated for both the sardine and anchovy
from the coastal Adriatic Sea (Vucetic 1975;
Casavola et al. 1998). We therefore undertook a
similar study to better understand the relationship between fish larval biomass. phytoplankton
abundance and production, and zooplankton
cycles and species composition in the coastal
waters of the south Tyrrhenian Sea.
Material and Methods
The investigated area extends from S. Agata di
Militello to Capo D'Orlando (Tyrrhenian Sea),
about two miles from the coast along the 5-10 00
isobaths (Fig. 1). This zone was identified as a
probable nursery area for many pelagic and
coastal fishes (Cefali et al.I997). Ichthyoplankton
was captured by a trawl net with a cod end of 1
mm mesh size from November 1994 to October
1995. Fish larvae, from a significative fraction of
each sample (about 10%) were sorted, weighed,
identified to species level and measured to nearest mm (TL). A total of 27 species were classified
(Table 1). Detailed information on sampling
strategy and methods are reported in Cefali et al.
(1997). The present results on fish larval biomass
were compared with data on production and
phytoplankton dominance (Magazzu and
Andreoli 1972, 1973; Magazzu et al. 1975), microzooplankton abundance (Sparla and Guglielmo
1994), zooplankton biomass and species composition in the coastal south Tyrrhenian Sea
(Scotto di Carlo 1985; Zagami et aI. 1996; L.
Guglielmo. unpublished data).
Results
The results show that during the investigated
period Sardina pilchardus was the most representative species (60%) followed by Gymnammodytes
cicirellus (25%). Other speciessuch as Aphia
minuta (6%), Engraulis encrasicholus (4%),
Sardinella aurita (2%),Pomatoschistus marmoraDipartimento eli Biologia Animale cd Ecologia Marina, Universita di Messina, Italy
F.M. Faranda, L. Gugliclmo, G. Sperle (eds)
Mediterranean Ecosystems: Structures and Processes
@ Springer-Verlag ltalia 2001
Relationship between Fish Larval Biomass and Plankton Production
in the South Tyrrhenian Sea
R. Bruno, A. Granata, A. Cefali, L. Guglielmo, G. Brancato, and P. Barbera
ABSTRACT
Fish larval biomass was compared with plankton abundance and production in the coastal
south Tyrrhenian Sea from November 1994 to October 1995. Sardina pilchardus was the most
representative species in biomass, followed by Gymnammodytes cicerellus. S. pilchardus showed
a larger spawning period (January to May) together with Engraulis encrasico/us (July to
November). Ichthyoplankton standing stocks peaked in February (6.28 gm- 2 ), preceeding both
the first primary production peak and the spring maximum zooplankton biomass in May. The
results demonstrate that no temporal overlapping occurred among fish larval species in the
coastal waters of the southern Tyrrhenian Sea.
Introduction
Our understanding of the structure and dynamics of coastal marine food webs has progressed
considerably in recent years. Cushing (1967,
1969) assumed that the spawning period of the
pelagic fishes was fixed and did not change with
environmental conditions. On the contrary, we
now know that the timing of spawning and successfulllarval fish recruitment are strongly related to plankton production and zooplankton
species composition (Sameoto 1982; Fortier
1995; Mousseau et al. 1998). This has also been
demonstrated for both the sardine and anchovy
from the coastal Adriatic Sea (Vucetic 1975;
Casavola et al. 1998). We therefore undertook a
similar study to better understand the relationship between fish larval biomass. phytoplankton
abundance and production, and zooplankton
cycles and species composition in the coastal
waters of the south Tyrrhenian Sea.
Material and Methods
The investigated area extends from S. Agata di
Militello to Capo D'Orlando (Tyrrhenian Sea),
about two miles from the coast along the 5-10 00
isobaths (Fig. 1). This zone was identified as a
probable nursery area for many pelagic and
coastal fishes (Cefali et al.I997). Ichthyoplankton
was captured by a trawl net with a cod end of 1
mm mesh size from November 1994 to October
1995. Fish larvae, from a significative fraction of
each sample (about 10%) were sorted, weighed,
identified to species level and measured to nearest mm (TL). A total of 27 species were classified
(Table 1). Detailed information on sampling
strategy and methods are reported in Cefali et al.
(1997). The present results on fish larval biomass
were compared with data on production and
phytoplankton dominance (Magazzu and
Andreoli 1972, 1973; Magazzu et al. 1975), microzooplankton abundance (Sparla and Guglielmo
1994), zooplankton biomass and species composition in the coastal south Tyrrhenian Sea
(Scotto di Carlo 1985; Zagami et aI. 1996; L.
Guglielmo. unpublished data).
Results
The results show that during the investigated
period Sardina pilchardus was the most representative species (60%) followed by Gymnammodytes
cicirellus (25%). Other speciessuch as Aphia
minuta (6%), Engraulis encrasicholus (4%),
Sardinella aurita (2%),Pomatoschistus marmoraDipartimento eli Biologia Animale cd Ecologia Marina, Universita di Messina, Italy
F.M. Faranda, L. Gugliclmo, G. Sperle (eds)
Mediterranean Ecosystems: Structures and Processes
@ Springer-Verlag ltalia 2001