Chaetognaths from the Laccadives with the New Record of Spadella angulata
321
fixed in 4% seawater f<;>rmaldehyde buffered with 1 % hexamine. In the laboratory, each
sample was divided into half, one sub-sample for biomass determination and the other
for taxonomic studies. From the latter, chaetognaths were sorted out and classified into
species. Each species was again subdivided into 5 maturity stages, taking into consideration the growth of the gonads.
n. Results
Thirteen species belonging to 4 genera Krohnitta, Pterosagitta, Sagitta and Spadella
were obtained from the collections (Fig. 6).
The species were:
Krohnitta pacifica (AIDA, 1897)
Pterosagitta draco (KROHN, 1853)
Sagitta bedoti (BERANECK,1895)
Sagitta bipunctata (QUOY and GAIMARD, 1827)
Sagitta enflata (GRASSI, 1881)
Sagitta ferox (DONCASTER, 1903)
Sagitta hexaptera (d'ORBIGNY, 1843)
Sagitta neglecta (AIDA, 1897)
Sagitta pacifica (TOKIOKA, 1940)
Sagitta pulchra (DONCASTER, 1903)
Sagitta regularis (AIDA, 1897)
Sagitta robusta (DONCASTER, 1903)
Spadella angulata (TOKIOKA, 1951)
Of these, S. ferox and Sp. angulata were encountered only in the Kalpeni collections.
1. Krohnitta pacifica
Moderately common in the waters surrounding the atolls. Highest number from
Kavaratti: 211 per 100 m 3 , from Kalpeni: 719 per 100 m 3 . Very rare in the Kavaratti
lagoon (average number 1 per 100 m 3 ), comparatively better represented in the Kalpeni
lagoon (average number 25 per 100 m 3 ). Maturity stage IV was dominant in almost all
collections.
2. Pterosagitta draco
More abundant at the Kavaratti (maximum number 39 per 100 m 3 ), at Kalpeni present
at only a few stations, the maximum number being 48 per 100 m 3 • Totally absent in the
Kavaratti lagoon, while in the Kalpeni lagoon the average number was 2 per 100 m 3 •
Stage IV was not represented in any of these collections and most of the specimens were
immature.
3. Sagitta bedoti
Common in the waters surrounding the atoll. Maximum at Kavaratti was 1213 per
100 m 3 , at Kalpeni 718 per 100 m\ but only at 2 stations. In the Kavaratti lagoon it was
poorly represented (average number 5 per 100 m 3 ) whereas at Kalpeni lagoon it was third
in abundance (167 per 100 m 3 ). Most of these were immature forms and stage IV was
moderately represented.
321
fixed in 4% seawater f<;>rmaldehyde buffered with 1 % hexamine. In the laboratory, each
sample was divided into half, one sub-sample for biomass determination and the other
for taxonomic studies. From the latter, chaetognaths were sorted out and classified into
species. Each species was again subdivided into 5 maturity stages, taking into consideration the growth of the gonads.
n. Results
Thirteen species belonging to 4 genera Krohnitta, Pterosagitta, Sagitta and Spadella
were obtained from the collections (Fig. 6).
The species were:
Krohnitta pacifica (AIDA, 1897)
Pterosagitta draco (KROHN, 1853)
Sagitta bedoti (BERANECK,1895)
Sagitta bipunctata (QUOY and GAIMARD, 1827)
Sagitta enflata (GRASSI, 1881)
Sagitta ferox (DONCASTER, 1903)
Sagitta hexaptera (d'ORBIGNY, 1843)
Sagitta neglecta (AIDA, 1897)
Sagitta pacifica (TOKIOKA, 1940)
Sagitta pulchra (DONCASTER, 1903)
Sagitta regularis (AIDA, 1897)
Sagitta robusta (DONCASTER, 1903)
Spadella angulata (TOKIOKA, 1951)
Of these, S. ferox and Sp. angulata were encountered only in the Kalpeni collections.
1. Krohnitta pacifica
Moderately common in the waters surrounding the atolls. Highest number from
Kavaratti: 211 per 100 m 3 , from Kalpeni: 719 per 100 m 3 . Very rare in the Kavaratti
lagoon (average number 1 per 100 m 3 ), comparatively better represented in the Kalpeni
lagoon (average number 25 per 100 m 3 ). Maturity stage IV was dominant in almost all
collections.
2. Pterosagitta draco
More abundant at the Kavaratti (maximum number 39 per 100 m 3 ), at Kalpeni present
at only a few stations, the maximum number being 48 per 100 m 3 • Totally absent in the
Kavaratti lagoon, while in the Kalpeni lagoon the average number was 2 per 100 m 3 •
Stage IV was not represented in any of these collections and most of the specimens were
immature.
3. Sagitta bedoti
Common in the waters surrounding the atoll. Maximum at Kavaratti was 1213 per
100 m 3 , at Kalpeni 718 per 100 m\ but only at 2 stations. In the Kavaratti lagoon it was
poorly represented (average number 5 per 100 m 3 ) whereas at Kalpeni lagoon it was third
in abundance (167 per 100 m 3 ). Most of these were immature forms and stage IV was
moderately represented.