Adv. mar. Biol., Vol. 9, 1971, pp. 1-100
THE BIOLOGY OF ASClDlANS
I.
11.
111.
IV.
V.
VI.
VII.
VIII.
Ix.
R. H. MILLAR
Dunstaffnuge Marine Research Laboratory, Oban,
Argyll, Scotland.
Introduction
. . .. .. .. .. . . . .
Feeding . . . . .. . . . . .. .. ..
A. " h e Feeding Mechanism
.. .. . . . .
Breeding .. .. . . . . . . .. .. ..
A. Breedingseason . . . . . . .. . . . .
B. Spawning . . . . . . . . . . . . . .
C. TheLenre
.. .. . . . . . . . .
Life Cycle: Growth, Succession of Generations and Mortality
Ecology . . . . . . . . . . . . . . . .
A. The Numbers and Biomass of Ascidians
. . ..
B. Changes in Populations . . .. .. .. ..
C. Factors Affecting Distribution and Abundance
. .
Predators, Parasites. Commensals and Symbionts . . ..
A. Predators . . . . . . .. .. .. ..
B. Commensals, Parasites and Symbionts
. . . .
Geographical Distribution
. . .. . . . . ..
A. Shallow-water Ascidians
.. .. .. ..
B. Deep-water Ascidians . . . . .. .. ..
Economic importance . . . . . . .. .. ..
A. Fouling . . . . . . .. . . . . ..
B. Food of Man, and of Commercial Fish
.. ..
C. Uptake of Harmful Substances
. . . . ..
References
. . . . . . . . . . . . . .
B. Food
.. . . . . .. .. . . . .
..
..
..
..
..
..
..
..
..
..
..
..
..
..
..
..
..
..
..
..
..
..
..
..
.. 1
.. 2
.. 2
.. 4
,.
6
,.
6
.. 13
.. 14
.. 22
.. 33
.. 33
.. 36
.. 36
.. 47
.. 48
.. 60
.. 66
. . 66
. . 69
.. 79
.. 79
.. 81
.. 82
.. 82
I. INTRODUCTION
Ascidians have been studied from many viewpoints, and a simple
analysis of the entries in the Zoological Record indicates the main
interests of recent investigators. Amongst publications appearing, for
instance, between 1963 and 1967 and dealing in part or whole with the
group, the number of papers having at least some mention of the various
subjects used in classifying the entries is as follows : general literature,
70 ; structure, 117 ; physiology, 151 ; reproduction, 34 ; development,
168; evolution and genetics, 31 ; ecology and habits, 90; distribution,
77. Since structure is taken to include histochemistry and cytochemistry, and development to include chemical embryology, it is
1
THE BIOLOGY OF ASClDlANS
I.
11.
111.
IV.
V.
VI.
VII.
VIII.
Ix.
R. H. MILLAR
Dunstaffnuge Marine Research Laboratory, Oban,
Argyll, Scotland.
Introduction
. . .. .. .. .. . . . .
Feeding . . . . .. . . . . .. .. ..
A. " h e Feeding Mechanism
.. .. . . . .
Breeding .. .. . . . . . . .. .. ..
A. Breedingseason . . . . . . .. . . . .
B. Spawning . . . . . . . . . . . . . .
C. TheLenre
.. .. . . . . . . . .
Life Cycle: Growth, Succession of Generations and Mortality
Ecology . . . . . . . . . . . . . . . .
A. The Numbers and Biomass of Ascidians
. . ..
B. Changes in Populations . . .. .. .. ..
C. Factors Affecting Distribution and Abundance
. .
Predators, Parasites. Commensals and Symbionts . . ..
A. Predators . . . . . . .. .. .. ..
B. Commensals, Parasites and Symbionts
. . . .
Geographical Distribution
. . .. . . . . ..
A. Shallow-water Ascidians
.. .. .. ..
B. Deep-water Ascidians . . . . .. .. ..
Economic importance . . . . . . .. .. ..
A. Fouling . . . . . . .. . . . . ..
B. Food of Man, and of Commercial Fish
.. ..
C. Uptake of Harmful Substances
. . . . ..
References
. . . . . . . . . . . . . .
B. Food
.. . . . . .. .. . . . .
..
..
..
..
..
..
..
..
..
..
..
..
..
..
..
..
..
..
..
..
..
..
..
..
.. 1
.. 2
.. 2
.. 4
,.
6
,.
6
.. 13
.. 14
.. 22
.. 33
.. 33
.. 36
.. 36
.. 47
.. 48
.. 60
.. 66
. . 66
. . 69
.. 79
.. 79
.. 81
.. 82
.. 82
I. INTRODUCTION
Ascidians have been studied from many viewpoints, and a simple
analysis of the entries in the Zoological Record indicates the main
interests of recent investigators. Amongst publications appearing, for
instance, between 1963 and 1967 and dealing in part or whole with the
group, the number of papers having at least some mention of the various
subjects used in classifying the entries is as follows : general literature,
70 ; structure, 117 ; physiology, 151 ; reproduction, 34 ; development,
168; evolution and genetics, 31 ; ecology and habits, 90; distribution,
77. Since structure is taken to include histochemistry and cytochemistry, and development to include chemical embryology, it is
1