42
1.S. Christiansen et al.
Polar fish produce relatively few, large eggs although egg size and
fecundity in fish are strongly linked to the mode of oviposition [9]. Fish
that spawn freely floating eggs (i.e. pelagic oviposition) usually produce
smaller eggs and are more fecund than species that deposit their eggs
onto/into substrates (i.e. demersal oviposition) [10].
The number of studies dealing with egg size and fecundity in fish has
increased considerably in recent years and includes reviews on Antarctic
fish reproduction [11,12]. In the light of the new information, this
communication outlines how egg size, fecundity, hence reproductive
output of marine, teleost species covary with both mode of oviposition (i.e.
pelagic vs demersal) and zoogeography (i.e. polar vs boreal).
Methods
The Data Base
A total of 59 marine, teleost fish species, represented by 85 data sets,
comprise this study. Data were examined with respect to the mode of
oviposition and the zoogeographic distribution of the different species
(Table 1). Although the evolutionary history of the polar marine
environments (Arctic and Antarctic) is rather different, we have divided the
fish into two broad zoogeographic categories viz polar (i.e. Arctic and
Antarctic combined) and boreal species. The distinction between boreal
and genuinely Arctic species follows the authority of Andriyashev and
Chernova [13]. We have also treated Antarctic fish as belonging to the
same zoogeographic region (i.e. within the boundary of the Antarctic
Convergence) although Kock [6] and Kock and Kellermann [11] have
made a further distinction between species living in the High-Antarctic
Zone and the Seasonal Pack-ice Zone, respectively. Further, fish were
grouped according to their mode of oviposition viz pelagic spawners, in
which eggs develop in the water column, and substrate spawners, in which
eggs develop on or close to the sea floor.
The data base also includes information about body length (in mm), egg
diameter (in mm) and fecundity of sexually mature fish (Table 1).
Information has been gathered mainly from Rass [3], Marshall [4], Kock
and Kellermann [11], Hubold [12], Rass [14] and Dolgov [15].
Essentially, the reproductive output of female fish depends on two keyparameters, egg size and fecundity. Egg volumes (in cubic millimetres)
were calculated from diameters assuming that eggs are spherical. We here
define the reproductive output by a female fish, i.e. maternal output (MO),
as: MO = EV x FEC, where EV is the average volume of a single egg and
1.S. Christiansen et al.
Polar fish produce relatively few, large eggs although egg size and
fecundity in fish are strongly linked to the mode of oviposition [9]. Fish
that spawn freely floating eggs (i.e. pelagic oviposition) usually produce
smaller eggs and are more fecund than species that deposit their eggs
onto/into substrates (i.e. demersal oviposition) [10].
The number of studies dealing with egg size and fecundity in fish has
increased considerably in recent years and includes reviews on Antarctic
fish reproduction [11,12]. In the light of the new information, this
communication outlines how egg size, fecundity, hence reproductive
output of marine, teleost species covary with both mode of oviposition (i.e.
pelagic vs demersal) and zoogeography (i.e. polar vs boreal).
Methods
The Data Base
A total of 59 marine, teleost fish species, represented by 85 data sets,
comprise this study. Data were examined with respect to the mode of
oviposition and the zoogeographic distribution of the different species
(Table 1). Although the evolutionary history of the polar marine
environments (Arctic and Antarctic) is rather different, we have divided the
fish into two broad zoogeographic categories viz polar (i.e. Arctic and
Antarctic combined) and boreal species. The distinction between boreal
and genuinely Arctic species follows the authority of Andriyashev and
Chernova [13]. We have also treated Antarctic fish as belonging to the
same zoogeographic region (i.e. within the boundary of the Antarctic
Convergence) although Kock [6] and Kock and Kellermann [11] have
made a further distinction between species living in the High-Antarctic
Zone and the Seasonal Pack-ice Zone, respectively. Further, fish were
grouped according to their mode of oviposition viz pelagic spawners, in
which eggs develop in the water column, and substrate spawners, in which
eggs develop on or close to the sea floor.
The data base also includes information about body length (in mm), egg
diameter (in mm) and fecundity of sexually mature fish (Table 1).
Information has been gathered mainly from Rass [3], Marshall [4], Kock
and Kellermann [11], Hubold [12], Rass [14] and Dolgov [15].
Essentially, the reproductive output of female fish depends on two keyparameters, egg size and fecundity. Egg volumes (in cubic millimetres)
were calculated from diameters assuming that eggs are spherical. We here
define the reproductive output by a female fish, i.e. maternal output (MO),
as: MO = EV x FEC, where EV is the average volume of a single egg and