Billfishes are popular big game in the ocean. In the marine environment, they serve important role as the top predators. Yet we do not completely know their life cycle especially during the larval stage. They feed primarily on copepods untill they are large enough to become pescivores. Our objective is seasonal understanding of spawning, larval growth, feeding, and migration within complex emvironment of Straits of Florida.
Samples are collected from series of 17 stations in the Gulf Stream, between South of Key Biscayne and South of Bimini. At each station, 1m and 4m MOCNESS of mesh size 150 µm and 800 µm respectively, are opened and closed at depth between surface ~ 100m, 100m ~ 75m, 75m ~ 50m, 50m ~ 25m, and 25m ~ surface. Specimens are strained and preserved in 95% ethanol to be identified and counted.
Here are pictures of the sampled copepods, with distinctive characters that are used in identification. Keys from Copepods of the Florida Current (Owre and Foyo, 1967) is used for the identification of animals.
Order CALANOIDA
| Name |
size (mm)
|
A1
|
Rostrum
|
Body |
P5
|
Urosome
|
Craudal ramus
|
|
Nannocalanus
minor (M) |
1.20~1.80
|
regular | absent | Ce +Th1, Th2, Th3, Th4, Th5 | assymmetrical | 5 seg. | regular |
|
(F)
|
1.80~2.25
|
absent
|
Ce +Th1, Th2, Th3, Th4, Th5 |
regular
|
4 seg.
|
regular
|
|
|
2.04~2.50
|
regular | absent | Ce +Th1, Th2, Th3, Th4, Th5 | assymmetrical | 5 seg. | regular | |
|
(F)
|
2.25~3.25
|
absent
|
Ce +Th1, Th2, Th3, Th4, Th5 pointed |
regular
|
4 seg.
|
regular
|
|
|
|
long | anchor | Ce +Th1, Th2, 3, 4 spines, Th5 | assymmetrical | 5 seg. | regular | |
|
(F)
|
2.90~3.80
|
anchor
|
Ce +Th1, Th2, 3, 4 spines, Th5 |
regular
|
3 seg.
|
regular
|
|
|
Acrocalanus
longicornis (M) |
0.95~1.25
|
regular | absent | Ce +Th1, Th2, Th3, Th4, Th5, hunch backed | assymmetrical | 5 seg. | regular |
|
(F)
|
1.00~1.26
|
absent
|
Ce +Th1, Th2, Th3, Th4, Th5, hunch backed |
very small
|
4 seg.
|
regular
|
|
|
Calocalanus
minutus (M) |
0.50~0.57
|
long | absent | assymmetrical | 5 seg. | regular | |
|
(F)
|
0.50~0.57
|
absent
|
very small
|
2 seg.
|
regular
|
||
|
Calocalanus
pavo (M) |
0.91~1.04
|
long | absent | Ce +Th1, Th2, Th3, Th4, Th5 pointed | assymmetrical | 5 seg. | regular |
|
(F)
|
0.88~1.20
|
absent
|
Ce +Th1, Th2, Th3, Th4, Th5 |
small
|
2 seg.
|
regular
|
|
|
0.55
|
long | absent | Ce +Th1, Th2, Th3, Th4, Th5 | assymmetrical | 5 seg. | regular | |
|
(F)
|
0.59~0.72
|
absent | Ce +Th1, Th2, Th3, Th4, Th5 | small | 2 seg. | regular | |
|
Clausocalanus
furcatus (M) |
0.70~0.92
|
regular | absent | Ce +Th1, Th2, Th3, Th4 +Th5 | assymmetrical | 5 seg. | regular |
|
(F)
|
0.94~1.31
|
absent
|
Ce +Th1, Th2, Th3, Th4 +Th5 |
very short
|
4 seg.
|
regular
|
|
|
2.88~3.20
|
regular | 2 points | Ce +Th1, Th2, Th3, Th4, Th5 | assymmetrical | 5 seg. | regular | |
|
(F)
|
3.40~3.64
|
2 points
|
Ce +Th1, Th2, Th3, Th4, Th5 |
absent
|
4 seg.
|
regular
|
|
|
Scolecithrix
danae (M) |
1.97~2.21
|
regular | absent | Ce +Th1, Th2, Th3, Th4, Th5, robust | assymmetrical | 5 seg. | regular |
|
(F)
|
1.80~2.40
|
absent
|
Ce +Th1, Th2, Th3, Th4, Th5, robust |
absent
|
4 seg.
|
regular
|
|
|
Temora
stylifera (M) |
1.65~1.80
|
regular
|
absent
|
Th1, Th2, Th3, Th4 +Th5 pointed |
assymmetrical
|
5 seg.
|
long
|
|
(F)
|
1.60~1.85
|
absent
|
Th1, Th2, Th3, Th4 +Th5 pointed |
regular
|
4 seg.
|
long
|
|
|
Lucicutia
fravicornis (M) |
1.30~1.70
|
regular
|
absent
|
Th1, Th2, Th3, Th4 +Th5 |
assymmetrical
|
5 seg.
|
long
|
|
(F)
|
1.30~2.00
|
absent
|
Th1, Th2, Th3, Th4 +Th5 |
regular
|
4 seg.
|
long
|
|
|
Heterorhabdus
lobatus (M) |
2.00~2.50
|
assymmetrical
|
notch
|
Th1, Th2, Th3, Th4 +Th5 |
assymmetrical
|
5 seg.
|
left longer
|
|
(F)
|
2.10~2.60
|
regular
|
notch
|
Th1, Th2, Th3, Th4 +Th5 |
regular
|
4 seg.
|
left longer
|
|
2.30~2.75
|
R geniculate | absent | Ce +Th1, Th2, Th3,Th4, Th5 assymmetrical point | assymmetrical | 5 seg. | regular | |
|
(F)
|
2.30~2.90
|
regular
|
absent
|
Ce +Th1 Th5 assymmetrical point |
small
|
3 seg.
|
regular
|
|
Candacia
paenelongimana (M) |
2.49
|
R geniculate
|
absent
|
Ce +Th1, Th2, Th3,Th4, Th5 assymmetrical point |
assymmetrical
|
5 seg.
|
regular
|
|
(F)
|
2.54~2.92
|
regular
|
absent
|
Ce +Th1, Th2, Th3,Th4, Th5 symmetrical point |
small
|
3 seg.
|
regular
|
|
Paracandacia
bispinosa (M) |
1.70
|
R geniculate
|
absent
|
Ce +Th1, Th2, Th3,Th4, Th5 symmetrical point |
assymmetrical
|
5 seg.
|
regular
|
|
(F)
|
1.80~1.82
|
regular
|
absent
|
Ce +Th1, Th2, Th3,Th4, Th5 symmetrical point |
small
|
3 seg.
|
regular
|
|
Pontella
securifer (M) |
3.42~4.20
|
R geniculate
|
lens (s)
|
Ce hooks, Th1, Th2, Th3,Th4, Th5 assymmetrical point |
assymmetrical
|
5 seg.
|
regular
|
|
(F)
|
3.65~4.55
|
regular
|
lens (s)
|
Ce hooks, Th1, Th2, Th3,Th4, Th5 assymmetrical point |
regular
|
2 seg.
|
regular
|
|
Pontellina
plumata (M) |
1.34~1.92
|
R geniculate
|
lens (s)
|
Ce +Th1, Th2, Th3,Th4, Th5 |
assymmetrical
|
5 seg.
|
regular
|
|
(F)
|
1.44~1.94
|
regular
|
lens (s)
|
Ce +Th1, Th2, Th3,Th4, Th5 |
regular
|
regular
|
|
|
Acartia
spp. (M) |
|
R geniculate
|
absent
|
Ce +Th1, Th2, Th3,Th4, Th5, smooth and slender |
assymmetrical
|
5 seg.
|
regular
|
|
(F)
|
|
regular
|
absent
|
Ce +Th1, Th2, Th3,Th4, Th5, smooth and slender |
regular
|
3 seg.
|
regular
|
Order HARPACTICOIDA
| Name |
size (mm)
|
A1
|
Rostrum
|
Body |
P5
|
Urosome
|
Craudal ramus
|
|
Microsetella
rosea (M) |
|
geniculate
|
beak
|
Ce, Th1, Th2, Th3, Th4 |
symmetrical
|
5 seg.
|
short
|
|
(F)
|
0.64~0.85
|
short
|
beak
|
Ce, Th1, Th2, Th3, Th4 |
symmetrical
|
4 seg.
|
short
|
|
Miracia
efferata (M) |
1.40~1.60
|
geniculate
|
lens (S)
together |
Ce, Th1, Th2, Th3, Th4 |
symmetrical
|
5 seg.
|
long
|
|
(F)
|
1.45~2.00
|
short
|
lens (S)
together |
Ce, Th1, Th2, Th3, Th4 |
symmetrical
|
4 seg.
|
long
|
|
Miracia
minor (M) |
|
geniculate
|
lens (S)
separate |
Ce, Th1, Th2, Th3, Th4 |
symmetrical
|
5 seg.
|
long
|
|
(F)
|
0.93
|
short
|
lens (S)
separate |
Ce, Th1, Th2, Th3, Th4 |
symmetrical
|
4 seg.
|
long
|
|
1.13~1.16
|
geniculate | projection | Ce, Th1, Th2, Th3, Th4 | symmetrical | 5 seg. | long | |
|
(F)
|
1.40~1.50
|
short
|
projection
|
Ce, Th1, Th2, Th3, Th4 |
symmetrical
|
4 seg.
|
long
|
|
Oculosetella
gracilis (M) |
1.15~1.30
|
geniculate
|
lens (S)
separate |
symmetrical
|
long
|
||
|
(F)
|
1.20~1.35
|
short
|
lens (S)
separate |
symmetrical
|
long
|
Order CYCLOPOIDA
| Name |
size (mm)
|
A1
|
Rostrum
|
Body |
P5
|
Urosome | Craudal ramus |
|
0.59~0.68
|
geniculate | flat | Ce, Th1, Th2, Th3, Th4 | long filament | 6 seg. | long | |
|
(F)
|
1.06~1.51
|
regular
|
conical |
Ce, Th1, Th2, Th3, Th4
|
short filament | 5 seg. | long |
Order POECILOSTOMATOIDA
| Name |
size (mm)
|
A1
|
Rostrum
|
Body |
P5
|
Urosome
|
Craudal ramus
|
|
Saphirella
spp. (M) |
|
short
|
absent |
Ce +Th1 and Th2 only
|
small | flat | |
|
(F)
|
|
short | absent |
Ce +Th1 and Th2 only
|
small | 3 seg. | flat |
|
Oncaea
mediterranea (M) |
0.74~0.97
|
short | absent | Ce, Th1, Th2, Th3, Th4 | very small | 6 seg. | < 2X ansgm |
|
(F)
|
1.14~1.26
|
short | absent | Ce, Th1, Th2, Th3, Th4 | very small | 5 seg. | > ansgm |
|
Oncaea
venusta (M) |
|
short | absent | Ce, Th1, Th2, Th3, Th4 | very small | 6 seg. | > 2X ansgm |
|
(F)
|
|
short | absent | Ce, Th1, Th2, Th3, Th4 | very small | 5 seg. | > ansgm |
|
Lubbockia
squillimana (M) |
1.80~2.10
|
long | triangular | Ce, Th1, Th2, Th3, Th4 | > gnsgm | 6 seg. | long |
|
(F)
|
1.45~1.60
|
short | conical | Ce, Th1, Th2, Th3, Th4 | > gnsgm | 5 seg. | long |
|
Pachos
punctatum (M) |
|
short | notch | extremely robust | short filament | ||
|
(F)
|
|
short | notch | extremely robust | short filament | ||
|
2.00~2.75
|
short | lens (S) | small | 6 seg. | flat | ||
|
(F)
|
2.00~2.75
|
short | lens (S) | small | 5 seg. | flat | |
|
Corycaeus (C.)
speciosus (M) |
1.49~1.85
|
short | lens (L) | Ce +Th1, Th2, Th3 +Th4 | short filament | 2 seg. | = ur |
|
(F)
|
1.78~2.20
|
short | lens (L) | Ce +Th1, Th2, Th3 +Th4 | short filament | 2 seg. | = ur |
|
Corycaeus (A.)
flaccus (M) |
1.28~1.68
|
short | lens (L) | Ce +Th1, Th2, Th3 +Th4 | short filament | 3 seg. | |
|
(F)
|
1.49~1.85
|
short | lens (L) | Ce +Th1, Th2, Th3 +Th4 | short filament | 1 seg. | > 1/2 ur |
|
Corycaeus (A.)
limbatus (M) |
1.15~1.20
|
short | lens (L) together |
Ce +Th1, Th2, Th3 +Th4 | short filament | 2 seg. | |
|
(F)
|
1.35~1.40
|
short | lens (L) | Ce +Th1, Th2, Th3 +Th4 | short filament | 1 seg. | 1/2 ur |
|
Corycaeus (O.)
catus (M) |
|
short | lens (L) | Ce +Th1, Th2, Th3 +Th4 | short filament | 3 seg. | |
|
(F)
|
|
short | lens (L) | Ce +Th1, Th2, Th3 +Th4 | short filament | 2 seg. | 1/2 gnsgm |
|
Corycaeus (O.)
latus (M) |
0.70~1.17
|
short | lens (L) | Ce +Th1, Th2, Th3 +Th4 | short filament | 2 seg. | |
|
(F)
|
0.80~1.18
|
short | lens (L) | Ce +Th1, Th2, Th3 +Th4 | short filament | 2 seg. | 1/2 gnsgm |
|
Farranula
gracilis (M) |
0.80
|
short | lens (L) together |
Ce +Th1, Th2 +Th3 +Th4 | short filament | 2 seg. | long |
|
(F)
|
1.00
|
short | lens (L) | Ce +Th1, Th2 +Th3 +Th4 | short filament | 2 seg. | long |
Questions to be answered on my part of the project.
Which species/ group is abundant in the zooplankton/ copepod community? Which animals are found in the stomach of billfish larvae? Is there a preference in billfish larvae? If so, is that due to the abundance or the energy content of the prey?
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