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A B C D-E F G H-J K L M N O-P Q-R S T U-V W-Y
close this section of the library Guinea, Michael L.


View the PDF document Aspects of the biology of the common Fijian sea snake Laticauda colubrina (Schneider)
Author:Guinea, Michael L.
Institution: University of the South Pacific.
Award: M.Sc.
Subject: Sea kraits, Sea snakes--Fiji
Date: 1986.
Call No.: pac QL 666 .O645 G8
BRN: 11320
Copyright:Over 80% of this thesis may be copied without the authors written permission

Abstract: I n v e s t i g a t i o n s i n t o the biology of the banded sea snake, Laticauda c o l u b r i n a , which i n h a b i t e d various islands in F i j i , were conducted during the p e r i o d , 1980 t o 1982. Studies concentrated on the morphology, reproductive b i o l o g y , and f l u c t u a t i o n s in population s i z e on a d a i l y and seasonal bases. T o x i c i t y studies were conducted using venom from captive snakes on mice and c h i c k muscle. 1. fldult female s u p e r i o r i t y was demonstrated by snout-vent length (uax = 143.5 cm) and weight (max = 1200 g ) . fldult males d i f f e r e d s i g n i f i c a n t l y from females in l e n g t h , weight, shape and t h i c k n e s s of the t a i l , t a i l l e n g t h , number of black bands, number of v e n t r a l scales, number of subcaudal s c a l e s , body scale rows at mid-body and vent, and the number of s u p r a l a b i a l scales. The number of subcaudal scales displayed the greatest difference between the sexes and was used for set;ing immature specimens. 2. Courtship and mating behaviour are documented. Seasonal reproduction was established f o r females by using ovary weight index, the size of the l a r g e s t f o l l i c l e in the ovary, and the presence of spermatozoa and oviducal eggs in the o v i d u c t s . Reproduction was confined to t h e summer months. Male r e p r o d u c t i v e cycles coincided with t h a t of -females. Eqgs, l a i d in c a p t i v i t y , incubated at room temperature i n 121-126 days. Eggs were not found in the w i l d . 3. Sexual maturity was attained by females at 24 months (s-v l e n g t h = 98 cml. Males reached m a t u r i t y at 15 months (s-v length = 70 cm). 4. The d i e t consisted of conger and moray e e l s , exclusively (Muraenesocidae and Muraenidae r e s p e c t i v e l y ) . 5. Adult sex r a t i o s varied from 2.4 : 1 (H : F) to 1.1 : 1 (F : M) , but generally did not d i f f e r from 1 s 1. 6. Mark and recapture studies were conducted on Sausau Island where the winter population was estimated at 1106 by using a zero-truncated geometric d i s t r i b u t i o n . The summer p o p u l a t i o n of 1398 was obtained by using a zero-truncated Poisson d i s t r i b u t i o n (Caughley, 1977), The percentage of the population which changed habitat per day decreased from 91 +_ 1.87. in winter to 72 +. 10.2X i n summer. This change of behaviour was assumed to be r e s p o n s i b l e f o r the change in c a t c h a b i l i t y which was inherent in the methods used to estimate the size of the p o p u l a t i o n . 7. While ashore, most snakes r e s t e d . A c t i v i t y in the p o p u l a t i o n was i n i t i a t e d by sunset, high t i d e and showers of r a i n . 8. Juvenile U . c o l u b r i n a f e l l prey to portunid crabs on the r e e f - f l a t . Predation on a d u l t specimens was not observed. M o r t a l i t y i n c l u d e d f i r e , exposure, dehydration and other unknown causes. 9. The thermal preference for L^_ colubrina was about 30aC. The body temperatures of snakes in the water d i f f e r e d only s l i g h t l y (max = 1.5°C) from the temperature of the water. Body temperatures of adults on land reached 7°C above a i r temperature and 5°C above ground temperature. 10. The morphology of the venom gland was documented and the f u n c t i o n a l fangs and teeth Here examined. Mean fang length of a d u l t females was 2.7 mm. The number of p a l a t i n e , ptsrygoid and dentary t e e t h were in agreement with those given by Mao and Chen (1980). fl single m a x i l l a r y tooth was present behind the fang, f o r each s k u l l examined. 11. The venom was a clear viscous l i q u i d which formed a white s o l i d when d r i e d . The maximum volume of venom per snake was 78 p i and the maximum percentage s o l i d was 41.87.. The percentage s o l i d increased in those snakes deprived of water during c a p t i v i t y . Venom i r r e v e r s i b l y blocked neuromuscular transmission i n c h i c k biventer c e r v i c i s nerve-muscle preparations. The LDoo was 0.35 mg/kg when i n j e c t e d ( i . p . l into mice. 12. The i m p l i c a t i o n s of the i n v e s t i g a t i o n s are discussed and areas f a r f u r t h e r research are o u t l i n e d .
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