Chaetognaths from the Laccadives with the New Record of Spa della angulata
323
23 per 100 m 3 and at Kalpeni 70 per 100 m 3 . All the different stages were present. Immature and stage I were predominant.
10. Sagitta pulchra
Very scarce: at Kavaratti present only at station 38 (14 per 100 m 3 ) and at Kalpeni
at 3 stations (maximum number 3 per 100 m 3 ). At Kalpeni lagoon encountered at
station 56 (2 per 100 m 3 ). Only stages III and IV were present at Kavaratti. At Kalpeni
immature specimens and stage I were also encountered.
11. Sagitta regularis
A common species around the atoll, particularly at Kavaratti (maximum 800 per
100 m 3 ). At Kalpeni the maximum was 718 per 100 m 3 and the species was absent in
the samples from stations 67, 68 and 74. Common in the Kavaratti and Kalpeni lagoon
stations; at Kavaratti dominant at station 36. Average number at Kavaratti 57 per 100 m 3
at Kalpeni 39 per 100 m 3 • At Kavaratti they were well represented by different stages,
especially stage IV; at Kalpeni the different stages were not well represented.
12. Sagitta robusta
Moderately common around the atoll. The maximum number at Kavaratti was
316 per 100 m 3 , at Kalpeni 257 per 100 m 3 • Poorly represented in the Kavaratti lagoon,
being present only at station 44. At Kalpeni lagoon it was moderately represented and
was absent only at stations 55 and 59. Average number at Kavaratti 1 per 100 m 3 , at
Kalpeni 49 per 100 m 3 • At Kavaratti the different stages were not well represented
whereas at Kalpeni a better representation of stage IV and immature stage was noticed.
13. Spadella angulata
This species was recorded only at station 55 at the southern part of the Kalpeni lagoon.
A total of 100 specimens was obtained out of which 52 were stage IV of maturity and
the rest stage II. Previously it has been recorded at Nanao Bay as Sp. cephaloptera f. angulata (TOKIOKA, 1951), in the coastal waters of Malay as Sp. angulata (TOKIOKA and
PATHANSALI, 1964) and west of Penang Island as Sp. angulata (PATHANSALI, 1968).
14. Quantitative Evaluation
The mean representation of Chaetognatha in and around the atolls are given below:
Average number of chaetognaths inside the lagoon
Average number of chaetognaths outside the lagoon
Kavaratti
no per 100 m 3
154
3 121
Kalpeni
no per 100 m 3
1068
3 175
At Kavaratti the water coming through the reef into the lagoon was found to be
improverished of its chaetognath fauna by a factor of 20, while the water coming into
the Kalpeni lagoon loses about 67% of its chaetognaths.
The abundance of chaetognaths at the Kavaratti atoll is represented in Fig. 4. Two
series of samples were taken, one during the rising tide and the other during the falling
tide, at the stations shown in Fig. 2, in time sequence. The curves representing the
abundance of chaetognaths outside the lagoon do not indicate a tidal cycle. However,
323
23 per 100 m 3 and at Kalpeni 70 per 100 m 3 . All the different stages were present. Immature and stage I were predominant.
10. Sagitta pulchra
Very scarce: at Kavaratti present only at station 38 (14 per 100 m 3 ) and at Kalpeni
at 3 stations (maximum number 3 per 100 m 3 ). At Kalpeni lagoon encountered at
station 56 (2 per 100 m 3 ). Only stages III and IV were present at Kavaratti. At Kalpeni
immature specimens and stage I were also encountered.
11. Sagitta regularis
A common species around the atoll, particularly at Kavaratti (maximum 800 per
100 m 3 ). At Kalpeni the maximum was 718 per 100 m 3 and the species was absent in
the samples from stations 67, 68 and 74. Common in the Kavaratti and Kalpeni lagoon
stations; at Kavaratti dominant at station 36. Average number at Kavaratti 57 per 100 m 3
at Kalpeni 39 per 100 m 3 • At Kavaratti they were well represented by different stages,
especially stage IV; at Kalpeni the different stages were not well represented.
12. Sagitta robusta
Moderately common around the atoll. The maximum number at Kavaratti was
316 per 100 m 3 , at Kalpeni 257 per 100 m 3 • Poorly represented in the Kavaratti lagoon,
being present only at station 44. At Kalpeni lagoon it was moderately represented and
was absent only at stations 55 and 59. Average number at Kavaratti 1 per 100 m 3 , at
Kalpeni 49 per 100 m 3 • At Kavaratti the different stages were not well represented
whereas at Kalpeni a better representation of stage IV and immature stage was noticed.
13. Spadella angulata
This species was recorded only at station 55 at the southern part of the Kalpeni lagoon.
A total of 100 specimens was obtained out of which 52 were stage IV of maturity and
the rest stage II. Previously it has been recorded at Nanao Bay as Sp. cephaloptera f. angulata (TOKIOKA, 1951), in the coastal waters of Malay as Sp. angulata (TOKIOKA and
PATHANSALI, 1964) and west of Penang Island as Sp. angulata (PATHANSALI, 1968).
14. Quantitative Evaluation
The mean representation of Chaetognatha in and around the atolls are given below:
Average number of chaetognaths inside the lagoon
Average number of chaetognaths outside the lagoon
Kavaratti
no per 100 m 3
154
3 121
Kalpeni
no per 100 m 3
1068
3 175
At Kavaratti the water coming through the reef into the lagoon was found to be
improverished of its chaetognath fauna by a factor of 20, while the water coming into
the Kalpeni lagoon loses about 67% of its chaetognaths.
The abundance of chaetognaths at the Kavaratti atoll is represented in Fig. 4. Two
series of samples were taken, one during the rising tide and the other during the falling
tide, at the stations shown in Fig. 2, in time sequence. The curves representing the
abundance of chaetognaths outside the lagoon do not indicate a tidal cycle. However,