5 . THE LITTORAL FISHES OF LITTLE CAYMAN (WEST INDIES)
G.W. P o t t s
'r1l.e ~ ? ~ & s s i f i c a t i o l l of l i t t o r a l f i s l ; fauj?as in tile CarLbbesrl i s d i s c u s s e d and a n a l t e r n a t i v e scheme i s s u g g e s t e d i n t h e l i g h t o f t h e p r e s e n t work. The f a u n a e l e m e n t s a r e t y p i c a l o f t h e a r e a and s u p p o r t t h e t h e o r y t h a t t h e C a r i b b e a n i s an i n t e g r a t e d z o o g e o g r a p h i c u n i t .
I n t r o d u c t i o n
During t h e summer o f 1975 t h e Royal S o c i e t y and Cayman I s l a n d Government s u p p o r t e d a n e x p e d i t i o n t o L i t t l e Cayman where t h e
o p p o r t u n i t y was t a k e n t o s m d y d i f f e r e n t a s p e c t s o f t h e e c o l o g y o f t h e i s l a n d . The p r e s e n t p a p e r examines t h e l i t t o r a l marine f i s h e s from two r o c k y s h o r e a r e a s , J a c k s o n ' s Bay and t h e West End r o c k s from L i t t l e C a p a n and d e s c r i b e s t h e i - r d i s t r i b u t i o n and h a b i t a t p r e f e r e n c e s *
The d i s t r i b u t i o n o f l i t t o r a l i n v e r t e b r a t e s h a s been w e l l c o v e r e d and i s d i s c u s s e d and reviewed i n s p e c i a l r e l a t i o n t o L i t t l e Cayinan by P o t t s ( 1 9 7 9 ) . By comparison t h e l i t t o r a l f i s h e s o f t h e West I n d i e s have n o t been examined i n g r e a t d e t a i l a p a r t from a few e a r l y p a p e r s by B r e d e r (1948, 1 9 5 4 ) , and o t h e r works on s i n g l e s p e c i e s s u c h a s t h o s e by Tavolga (1950a and b ) and Aronson (1951, 1971) and o t h e r s . F o r more g e n e r a l a c c o u n t s o f t h e s h a l l o w w a t e r f i s h e s o f t h e C a r i b b e a n i t i s n e c e s s a r y t o examine t h e work by Longley and H i l d e b r a n d (1941) from t h e T o r t u g a s , F l o r i d a w i t h many u s e f u l e c o l o g i c a l n o t e s and t h e books b y Beebe and Tee-van ( 1 9 3 3 ) , R a n d a l l ( 1 9 6 8 ) , and Bohlke and C h a p l i n ( 1 9 6 8 ) . The l a t t e r i s e s p e c i a l l y u s e f u l i n h a v i n g a f u l l b i b l i o g r a p h y o f p a p e r s c o v e r i n g t h e taxonomy o f f i s h e s o f t h e r e g i o n . The P a c i f i c c o a s t o f America and t h e i s l a n d s of t h e t o p i c a l P a c i f i c have been examined by H i a t t and S t r a s b u r g (1960)
,
G o s l i n e (1965),
A t o l l Research B u l l e t i n No. 2 4 1 : 4 3 - 5 2 , 1 9 8 0 .
Thompson and Lehner (1976) and o t h e r s and o f f e r many u s e f u l e c o l o g i c a l p a r a l l e l s and comparisons t h a t w i l l be d i s c u s s e d l a t e r .
C l a s s i f i c a t i o n o f L i t t ~ r a l F i s h e s
The l i t t o r a l r e g i o n o f L i t t l e Cayman i s d e s c r i b e d by P o t t s (1979) i n a p a p e r on t h e d i s t r i b u t i o n and z o n a t i o n o f t h e common s p e c i e s of m o l l u s c and c r u s t a c e a n . P o t t s a l s o i n c l u d e s t i d a l d a t a which show c l e a r l y t h a t t h e low t i d a l r a n g e i s l e s s l i k e l y t o have an e f f e c t on t h e d i s t r i b u t i o n on l i t t o r a l s p e c i e s t h a n t h e s u r g e and s p r a y from wave a c t i o n . While f o r t h e d i s t r i b u t i o n o f l i t t o r a l i n v e r t e b r a t e s i t h a s been c o n v e n i e n t t o a d o p t t h e c l a s s i f i c a t i o n and t e r m i n o l o g y o u t l i n e d by Stephenson and Stephenson (1.952) and which i s sumn~arised by Doty (1.957)
,
f o r t h e l i t t o r a l f i s h i t i s more a p p r o p r i a t e t o u s e t h e c l a s s i f i c a t i o n o f Crosi.ine c1965) and FiFatt and S t r a s b r i r g (1960)
.
C a s l i n e d i v i d e s t h e - .. ~ . i ; _ : L ~ ~ & : ! . ye(ji011 in t c t w c j ; r;k,.- " s u r g e zone" i,qhich represeyi - t s e??c
,
' 1.:11 ~ ~ o z a l r e g i o n o r m i d l i t t o r a l o f S t e p h e n s o ~ l and Steplensor1 ( 1 9 5 2 ) arici
.
-
/ , h i & i s xasllied by the s u r g e acti.cm ~f wzves as ; . j i - i . ~ ~s thc n o r ~ n a l r i s e and f a l l of s e e l e v e l d u r i n g t h e tidal c y c l e , and s e c o n d l y t h e " s p l z s h ./ol.ie" ..* ' - '
-- ~ v n l c h is c c n q a r a b l e - w i t h t h e s u p r a l i t t o r a l f r i n g e and which i s w e t t e d o n ? ,y by s p r a y f r o n t h e a c t i o n o f win6 ;-.nii waves. H i a t t S t r a s b u r g (1.960) c a l l t h e s e t h e ' i n t e r t i d a l ' and ' s u p r a t i d a l h o n e s r e s p e c t i v e l y .
T h i s c l a s s i f i c a t i o n i d e n t i f i e s t h e l i t t o r a l r e g i o n i n t e r m s o f t h e i n f l u e n c e o f wave and t i d a l a c t i o n on t h e s h o r e . Within t h i s framework t h e f i s h p o p u l a t i o n h a s been c o n s i d e r e d under a f u r t h e r c l a s s i f i c a t i o n based upon t h e b i o l o g i c a l a d a p t a t i o n and permanence o f t h e f i s h f a u n a t o t h e r e g i o n ,
B r e d e r (1948) d e s c r i b e d t h e l i t t o r a l f i s h a s e i t h e r t y p i c a l , c a s u a l o r a c c i d e n t a l , b u t t h e s e c a t e g o r i e s a r e n o t always e a s y t o a p p l y and i t i s p e r h a p s somewhat e a s i e r t o u s e G i b s o n ' s (1969) b r o a d e r c l a s s i f i c a t i o n , I n t h i s , B r e d e r r s ' c a s u a l i and ' a c c i d e n t a l ' c a t e g o r i e s a r e g r o w e d a s
' p a r - t i a i r e s i d e n t s ' , b u t i n a d d i t i o n t e m p o r a l v a r i a t i o n s a r e allowed f o r by t h e c a t e g o r i e s of ' t i d a l ' and ' s e a s o n a l ' v i s i t o r s . I n a c t u a l f a c t t h e p a r t i a l r e s i d e n t s c o u l d b e e i t h e r t i d a l o r s e a s o n a l and i t would seem more u s e f u l t o d e f i n e t h e f i s h a s e i t h e r r e s i d e n t i a l o r t r a n s i e n t , and t o s u b d i v i d e t h e t r a n s i e n t groups a s e i t h e r t i d a l o r s e a s o n a l . T h i s i n f a c t c o v e r s most problems a s s o c i a t e d w i t h t h e e a r l i e r
c l a s s i f i c a t i o n , b u t l e a v e s u n r e s o l v e d t h e need f o r a group t o c o v e r t h o s e s p e c i e s t h a t may o n l y o c c u r i n t h e l i t t o r a l r e g i o n a t a c e r t a i n s t a g e o f t h e i r ontogeny. To some e x t e n t t h i s i s c o v e r e d by t h e
h e a d i n g o f s e a s o n a l v i s i t o r s , b u t t h i s might b e t t e r b e d i v i d e d i n t o two t o d e s c r i b e s e a s o n a l v i s i t o r s t h a t r e p r e s e n t a d u l t m i g r a n t s and t h o s e which a r e p r e s e n t a s p a r t o f t h e i r e s s e n t i a l ontogeny. The r e v i s e d
c l a s s i f i c a t i o n recommended f o r l i t t o r a l f i s h i s b r i e f l y summarised i n T a b l e 5 and i t i s t h i s c l a s s i f i c a t i o n t h a t i s a d o p t e d i n t h e p r e s e n t work.
While t h i s c l a s s i f i c a t i o n may a s s i s t t o i d e n t i f y t h e r e l e v a n c e o f a f i s h i n t h e l i t t o r a l zone i t can o n l y b e used a s a rough g u i d e i n t h e c a t e g o r i s a t i o n o f s p a t i a l and t e m p o r a l f a c t o r s c o n t r o l l i n g l i t t o r a l f i s h
p o p u l a t i o n s . V a r i a b i l i t y i n dependence upon t h e l i t t o r a l environment w i l l be s p e c i e s s p e c i f i c and a c l a s s i f i c a t i o n of t h i s k i n d can o n l y be o f advantage i n comparing between s p e c i e s a t t h e b r o a d e s t l e v e l .
Table 5. C l a s s i f i c a t i o n o f l i t t o r a l f i s h e s
I R e s i d e n t i a l S p e c i e s
Me thods
The a r e a s chosen f o r examination were a t West End r o c k s i n t h e w e s t and a t J a c k s o n ' s Bay i n t h e North o f L i t t l e Cayman. The more exposed rock o u t c r o p s a t t h e E a s t End and b l u f f end o f t h e i s l a n d o n l y c o n t a i n e d r e l a t i v e l y s m a l l p o o l s on a s t e e p s h o r e and c o n t a i n e d r a t h e r few s p e c i e s of l i t t o r a l f i s h . For t h i s r e a s o n it was d e c i d e d t o c o n c e n t r a t e on t h e p o o l s on t h e more s h e l t e r e d s i d e s of t h e i s l a n d . Before p o o l s were s u b j e c t e d t o d i s t u r b a n c e o b s e r v a t i o n s were made o f t h e h a b i t s o f t h e f i s h s p e c i e s p r e s e n t . T h i s was t h e n followed by a survey o f t h e e x t e n t and depth o f t h e p o o l ,
L i t t o r a l f i s h were c o l l e c t e d a t low water by u s i n g t h e f i s h a n a e s t h e t i c Quinaldine i n t h e manner s u g g e s t e d by Gibson ( 1 9 6 7 ) . F i r s t l y t h e rocks and l a r g e r s t o n e s were moved from t h e pool and t h e n a m i x t u r e o f Quinaldine mixed one t o f o u r w i t h a c e t o n e was s q u i r t e d i n t o t h e pool from a p l a s t i c wash b o t t l e . The mixture was d i r e c t e d i n t o c r e v i c e s i n t h e rock where many of t h e s m a l l e r l i t t o r a l s p e c i e s h i d e and t h e water was a g i t a t e d t h o r o u g h l y . As soon a s f i s h showed s i g n s o f a n a e s t h e s i a t h e y were dipped o u t o f t h e pool w i t h a n e t and t r a n s f e r r e d t o a bucket o f c l e a n s e a water where t h e y r e v i v e d . I t i s i n t e r e s t i n g t o n o t e t h a t a s w e l l a s f i s h t h e stomatopods, P s e u d o s q u i l l a s p . and G o n o d a c t y l u s s p . were a l s o a f f e c t e d by t h e Quinaldine and could be e a s i l y c o l l e c t e d . The f i s h were t h e n examined and p r o v i s i o n a l
i d e n t i f i c a t i o n s made o f t h e l i v i n g specimens b e f o r e t h e y were n a r c o t i s e d and p r e s e r v e d i n 10% Formalin. F i g u r e 20 r e p r e s e n t s d i a g r a m m a t i c a l l y t h e f i s h f a u n a s o f t h e s p l a s h and s u r g e l e v e l p o o l s .
R e s u l t s
A summary o f t h e l i t t o r a l f i s h c o l l e c t e d on L i t t l e Cayman i s given i n Table 6 t o g e t h e r with d e t a i l s of t h e mean s i z e , sample s i z e , zonal
T a b l e 6 . T a b l e i n d i c a t i n g t h e mean s i z e , sample s i z e and h a b i t a t p r e f e r e n c e o f t h e f i s h e s found occupying s i x l i t t o r a l rock poo1.s.
SPECIES [ o l o c e n t r i d a e
A d i o r y x v e x i l l a r i u s (Poey) b b i i d a e
B a t h y q o b i u s ~ o ~ p o r a t o r (Cuv. and V a l . ) 'omacen t r i d a e
A b u d e f d u f t a u r u s (Miill. and T r o s ) A . s a x a t i l i s (L)
E u p o m a c e n t r u s ~ e u c o s t i c t u s (Miill. and Tros) , u t j a n i d a e
L u t j a n u s a p o d u s (Walbaum)
; e r r i d a e
G e r r e s c i n e r e u s (Walbaum)
E u c i n o s t o m u s a r y e n t e u s ( B a i r d & G i r a r d ) b b i e s c o i d a e
Tomicodon f a s c i a t u s ( P e t e r s ) ' e t r a d o n t i d a e
C a n t h i y a s t e r r o s t r a t a (Bloch)
H a b i t a t p r e f e r e n c e Zonal l e v e l
Chae t o d o n t i d a e
Pornacanthus p a r u loch) Muraenidae
Echidna c a t e n a t a l lock) Enchel y c o r e sp
.
L a b r i d a e
Thalassoma b i f a s c i a t u m ( B l o c h ) A c a n t h u r i d a e
A c a n t h u r u s s p . ( 2 c h i r u r q u s )
A = A d u l t J = J u v e n i l e
l e v e l and h a b i t a t p r e f e r e n c e s . The f i s h o f t h e s p l a s h zone w i l l i n c l u d e o n e s c o l l e c t e d from t h e s u p r a l i t t o r a l f r i n g e and u p p e r p a r t o f t h e m i d l i t t o r a l zone w h i l e t h o s e o f t h e s u r g e zone a r e c o m p l e t e l y l i t t o r a l a n d were found i n p o o l s down t o t h e i n f r a l i t t o r a l f r i n g e . P r o v i s i o n a l f i e l d i d e n t i f i c a t i o n were made from t h e book by C h a p l i n and S c o t t (1972) and t h e s e were s u b s e q u e n t l y checked w i t h t h e i m p o r t a n t r e f e r e n c e books o f R a n d a l l (1968) and Bohlke and C h a p l i n ( 1 9 6 8 ) .
O f t h e 1 5 s p e c i e s c a u g h t from 12 f a m i l i e s , it i s s t r i k i n g t h a t o n l y t h r e e s p e c i e s were found t o occupy b o t h t h e s p l a s h zone and t h e s u r g e z o n e , B a t h y g o b i u s s o p o r a t o r , A b u d e f d u f s a x a t i l i s and T o m i c o d o n f a s c i a t u s
.
I t must b e assumed t h a t some s p e c i e s o f t h e upper s p l a s h zone m i g h t n o r m a l l y b e found i n t h e s u r g e zone p o o l s s i n c e a l l b u t one a r e c o n s i d e r e d t r a n s i e n t l i t t o r a l s p e c i e s which a t some s t a g e w i l l spend t i m e o f f s h o r e i n t h e s u b l i t t o r a l r e g i o n . By comparison none o f t h e s u r g e l e v e l s p e c i e s c o u l d b e c o n s i d e r e d r e s i d e n t i a l l i t t o r a l s p e c i e s most o f which a r e more commonly found on t h e f o r e - r e e f t e r r a c e and o n l y t h e j u v e n i l e s o f T h a l a s s o m b i f a s c i a t u m were found w i t h any r e g u l a r i t y i n l i t t o r a l p o o l s . Only B. s o p o r a t o r was c o n f i n e d t o t h e l i t t o r a l r e g i o n and n o t s e e n below t i d e m a r k s ,
The h a b i t a t p r e f e r e n c e s o f t h e s p e c i e s i n d i c a t e t h a t u n d e r
u n d i s t u r b e d c o n d i t i o n s t h e y c a n b e b r o a d l y grouped i n t o t h o s e t h a t s w i m i n mid-water, b e n t h i c s p e c i e s t h a t k e e p c l o s e t o t h e r o c k o f t e n w i t h t h e a i d o f a n a t o m i c a l a d a p t a t i o n s s u c h a s m o d i f i e d f i n s , and t h o s e t h a t t e n d t o remain i n c r e v i c e s . T h e r e i s some o v e r l a p between t h e s e
g r o u p s a s some b e n t h i c s p e c i e s may a l s o u s e c r e v i c e s and mid-water s p e c i e s may a d o p t them when d i s t u r b e d , o r a t c e r t a i n t i m e s o f t h e d a y . T h e r e may a l s o b e o n t o g e n e t i c d i f f e r e n c e s n o t r e c o g n i s e d d u r i n g t h e p r e s e n t work. On t h e whole t h e c r e v i c e d w e l l e r s , e , g . Muraenidae, t e n d t o b e c r e p u s c u l a r o r n o c t u r n a l i n t h e i r h a b i t s .
The m a j o r i t y o f s p e c i e s were immature and o n l y 8 . s o p o r a t o r , A. v e x i l l a r i u s
,
Tomicodon f a s c i a t u s and C a n t h i g a s t e r r o s t r a t a werer e p r e s e n t e d b y a d u l - t specimens a l t h o u g h even t h e s e were s m a l l e r t h a n t h e a d u l t s shown i n R a n d a l l (1958) and Bohlke and C h a p l i n ( 1 9 6 8 ) .
I n a d d i t i o n t o t h e s p e c i e s l i s t e d i n T a b l e 6 o n e o t h e r f i s h s p e c i e s was c o l l e c t e d from West End r o c k s , Diodon h o l a c a n t h u s . t h i s s i n g l e m a t u r e specimen ( 3 1 5 mrn) must b e c o n s i d e r e d a t r a n s i e n t p o o l s p e c i e s , a s w h i l e n o t uncommon on t h e s h a l l o w u p p e r r e e f t e r r a c e t o g e t h e r w i t h D . h i s t r i x , it does n o t normally t o l e r a t e t h e u n s t a b l e p o o l environment.
T h i s specimen was found b e n e a t h a v e r y l a r g e f l a t b o u l d e r which m u s t have p r o v i d e d t h e s h e l t e r n e c e s s a r y f o r t h i s r e l a t i v e l y weak swimmer.
Another s p e c i e s , t h e Hardhead s i l v e r s i d e A t h e r i n o m o r u s s t i p e s (mean t o t a l l e n g t h 67 mm, ST = 8 . 1 , n = 37) were found i n a g r o u p o f two o r t h r e e hundred i n d i v i d u a l s i n an i n l e t a t West End r o c k s where t h e y k e p t c l o s e t o t h e w a t e r s e d g e on t h e r i s i n g t i d e . I t i s p r o b a b l e t h a t t h i s s p e c i e s may a l s o b e t r a p p e d i n low l e v e l p o o l s on t h e f a l l i n g t i d e .
Q u i n a l d i n e a s w e l l a s n a r c o t i s i n g t h e l i t t o r a l f i s h a l s o a f f e c t e d t h e stomatopods t h a t were common i n t h e l i t t o r a l and s u b l i t t o r a l
r e g i o n . Two g e n e r a were c o l l e c t e d , G o n o d a c t y l u s s p . t h a t was found i n
s p l a s h and s u r g e l e v e l p o o l s and P s e u d o s q u i l l a s p . found o n l y i n t h e l o w e r s u r g e p o o l s .
D i s c u s s i o n
I n t e m p e r a t e r e g i o n s where t h e t i d a l r a n g e i s o f t e n l a r g e , t h e l i t t o r a l r e g i o n may p r o v i d e an e x t e n s i v e p l a t f o r m w i t h l a r g e and
permanent r o c k p o o l s i n which many s p e c i e s o f f i s h a r e a b l e t o e s t a b l i s h t h e m s e l v e s . The f i s h f a u n a i s f u r t h e r a s s i s t e d by t h e development o f a c o n s i d e r a b l e a l g a l canopy which o f f e r s a d i v e r s e h a b i t a t i n which
l i t t o r a l f i s h e s can l i v e t o g e t h e r w i t h a l a r g e r a n g e o f p o t e n t i a l food o r g a n i s m s . By c o n t r a s t t h e l i t t o r a l r e g i o n o f t r o p i c a l i s l a n d s i s o f t e n p o o r l y d e v e l o p e d w i t h a s m a l l t i d a l r a n g e and r e l a t i v e l y
i n c o n s p i c u o u s f l o r a . Over much o f t h e t r o p i c s t h e t i d a l r a n g e i s l e s s t h a n one m e t r e and t h e n a t u r e and e x t e n t o f t h e s h o r e and i t s a s s o c i a t e d f a u n a and f l o r a a r e d e t e r m i n e d b y t h e d e g r e e o f wave a c t i o n r a t h e r t h a n by t i d a l f a c t o r s ( D o t y , 1 9 5 7 ; H i a t t and S t r a s b u r g , 1960 and G o s l i n e , 1 9 6 5 ) . I n a d d i t i o n , t h e p h y s i c a l environment n e c e s s i t a t e s t h a t l i t t o r a l f i s h a r e t o l e r a n t o f t e m p e r a t u r e e x t r e m e s and e m e r s i o n , t o g e t h e r w i t h t h e r e l a t e d problems o f oxygen t e n s i o n , pH, s a l i n i t y , and d e s i c c a t i o n . These f a c t o r s and o t h e r a s p e c t s o f t h e a d a p t a t i o n s shown by l i t t o r a l f i s h e s t o l i f e on s h o r e a r e r e v i e w e d by Gibson ( 1 9 6 3 ) .
A p a r t from t h e e a r l y work o f B r e d e r (1948, 1954) most work on l i t t o r a l f i s h f a u n a s from t h e C a r i b b e a n h a s b e e n done on s p e c i f i c a s p e c t s o f t h e b i o l o g y o f s i n g l e s p e c i e s . On L i t t l e Cayman t h e o n l y permanent l i t t o r a l r e s i d e n t was t h e F r i l l f i n goby B a t h y g o b i u s s o p o r a t o r , o c c u r r i n g a t a l l t i d a l l e v e l s i n r o c k p o o l s . T h i s f i s h h a s been
s u b j e c t e d t o more r e s e a r c h t h a n any o t h e r C a r i b b e a n s p e c i e s w i t h
i m p o r t a n t work on i t s locomotion and o r i e n t a t i o n by Aronson (1951, 1 9 7 1 ) , and upon o t h e r a s p e c t s o f i t s l i f e c y c l e and s e n s o r y b i o l o g y by Tavolga
(1950a and b ) . No l a r g e s c a l e s u r v e y on t h e e c o l o g i c a l r e l a t i o n s o f t h e f i s h f a u n a o f t h e C a r i b b e a n h a s been p u b l i s h e d , o f t h e k i n d c a r r i e d o u t by H i a t t and S t r a s b u r g (1960) f o r t h e M a r s h a l l I s l a n d s , b u t none- t h e - l e s s t h e books o f R a n d a l l (1968) and Bohlke and C h a p l i n (1968) do p r o v i d e much u s e f u l e c o l o g i c a l i n f o r m a t i o n on i n d i v i d u a l s p e c i e s , t o g e t h e r w i t h d e s c r i p t i o n s o f t h e i r known g e o g r a p h i c r a n g e s .
The Cayman g r o u p o f i s l a n d s l i e i n t h e deep w a t e r o f t h e Cayman T r e n c h between Jamaica and Cuba. For t h i s r e a s o n t h e l i t t o r a l f i s h f a u n a i s p a r t i c u l a r l y i n t e r e s t i n g a s t h e p r o b l e m s a s s o c i a t e d w i t h t h e i r d i s p e r s a l a c r o s s deep w a t e r a r e c o n s i d e r a b l e and it m i g h t b e e x p e c t e d t h a t some form o f endermism m i g h t o c c u r among f i s h r e s t r i c t e d t o s h a l l o w w a t e r . I n f a c t no u n u s u a l f a u n a l e l e m e n t s were found among t h e s h o r e f i s h e s a l l o f which a r e r e c o r d e d from Cuba ( D u a r t e - B e l l o and B u e s a , 1973)
,
and which c o n f i r m s t h e view t h a t t h e C a r i b b e a n c a n b e r e g a r d e d a s a n i n t e g r a t e d z o o g e o g r a p h i c u n i t w i t h r e l a t i v e l y f r e e mixing among t h e f i s h p o p u l a t i o n o f t h e r e g i o n . D e s p i t e t h i s , L i t t l e Cayman had o n l y f o u r l i t t o r a l f i s h common t o t h o s e l i s t e d by B r e d e r(1948) from Bimini i n t h e Bahamas. These were t h e u b i q u i t o u s s p e c i e s B. s o p o r a t o r , T. b i f a s c i a t u m , E . l e u c o s t i c t u s and A b u d e f d u f s a x a t i l i s . The r e m a i n i n g s p e c i e s were d i f f e r e n t , b u t r e p r e s e n t e d s i m i l a r f a m i l i e s t h a t a r e t y p i c a l o f t h e l i t t o r a l r e g i o n , b o t h w i t h i n t h e C a r i b b e a n a r e a
and t h e t r o p i c a l P a c i f i c ( H i a t t and S t r a s b u r g , 1960; G o s l i n e , 1965 and Thompson and Lehner, 1976) and a l s o t o some e x t e n t t h e l i t t o r a l zone from t e m p e r a t e r e g i o n s (Gibson 1 9 6 9 ) . I t seems t h a t t h e c o l o n i s a t i o n of t h e t u r b u l e n t and u n s t a b l e l i t t o r a l r e g i o n h a s o n l y been p o s s i b l e by r e l a t i v e l y few f a m i l i e s o f f i s h which have been a b l e t o d e v e l o p b e h a v i o u r a l , a n a t o m i c a l and p h y s i o l o g i c a l a d a p t a t i o n s a p p r o p r i a t e t o
t h e l i t t o r a l environment. Many o f t h e s e a d a p t a t i o n s a r e d e s c r i b e d and d i s c u s s e d i n t h e p a p e r s mentioned above t o which s h o u l d b e added t h e work o f F i s h e l s o n ( 1 9 6 3 ) , Gibson (1967a and b ) and W i l l i a m s ( 1 9 5 7 ) .
While t h e l i t t o r a l f i s h o f L i t t l e Cayman a r e c o n f i n e d t o a
r e l a t i v e l y r e s t r i c t e d environment i t can b e s e e n by examining T a b l e 6 t h a t r a t h e r few a r e l i k e l y t o b e i n c o m p e t i t i o n f o r s p a c e o r food a s n o t o n l y do t h e y show d i f f e r e n t s p a c i a l and t e m p o r a l a c t i v i t y p a t t e r n s , b u t a l s o d i f f e r e n c e s i n f e e d i n g h a b i t s . With t h e predominance o f
c a r n i v o r o u s s p e c i e s t h e s i t u a t i o n i s e s s e n t i a l l y s i m i l a r t o t h a t o f Californian t i d e p o o l s d e s c r i b e d by Mitchell ( 1 9 5 3 ) .
On L i t t l e Cayman f o u r s p e c i e s were i d e n t i f i e d a s b e i n g r e s i d e n t i a l i n t h e l i t t o r a l r e g i o n . The o t h e r s a r e t y p i c a l o f s e v e r a l groups o f s h a l l o w w a t e r t r o p i c a l f i s h which a r e w i d e l y d i s t r i b u t e d o v e r t h e upper r e e f t e r r a c e s and back r e e f i n c l u d i n g a t t i m e s t h e l i t t o r a l r e g i o n , O t h e r s p e c i e s formed a more t r a n s i e n t element and were m o s t l y r e p r e s e n t e d by j u v e n i l e i n d i v i d u a l s o f s h a l l o w s u b l i t t o r a l s p e c i e s . Some, s u c h a s A b u d e f d u f s a x a t i l i s , A. t a u r u s , L u t j a n u s a p o d u s and Tomicodon f a s c i a t u s were r e l a t i v e l y common i n r o c k p o o l s and i t must b e supposed t h a t t h e young o f t h e s e and o t h e r s p e c i e s o f f i s h may remain i n t h e s h a l l o w beach zone. I n t h i s r e g i o n t h e y would b e p r o t e c t e d from t h e p r e d a t o r y s p e c i e s t h a t f r e q u e n t t h e r e e f p l a t f o r m . O t h e r s p e c i e s a r e w i d e s p r e a d a s t h e H o l o c e n t r i d , A d i o r y x v e x i l l a r i u s which i s common b e n e a t h b o u l d e r s i n r o c k p o o l s and may a l s o b e found d o w n , t o a d e p t h o f 20 m on t h e lower f o r e - r e e f t e r r a c e . Gibson (1969) a l s o d e s c r i b e d a g r o u p o f l i t t o r a l f i s h e s , t h e " s e a s o n a l v i s i t o r s " , which a r e r e p r e s e n t e d o n l y a t s p e c i f i c t i m e s o f t h e y e a r , o f t e n a s s o c i a t e d w i t h spawning
m i g r a t i o n s . U n f o r t u n a t e l y , t h e b r i e f p e r i o d on L i t t l e Cayman d i d n o t p e r m i t a f u l l e x a m i n a t i o n of t h e s e s p e c i e s .
Acknowledaements
I s h o u l d l i k e t o acknowledge t h e f i n a n c i a l and o t h e r s u p p o r t g i v e n by t h e Royal S o c i e t y and Cayman I s l a n d Government and i n p a r t i c u l a r t o D r M.E.C. G i g l i o l i and v a r i o u s members o f h i s s t a f f a t t h e Mosquito R e s e a r c h and C o n t r o l U n i t . I s h o u l d l i k e t o t h a n k George G i g l i o l i and Eugene P a r s o n s f o r f i e l d a s s i s t a n c e and Roger Swinfen f o r h e l p w i t h m a t e r i a l a f t e r t h e r e t u r n t o t h e Plymouth L a b o r a t o r y . I am g r a t e f u l t o t h e D i r e c t o r o f t h e Marine B i o l o g i c a l A s s o c i a t i o n f o r p e r m i s s i o n t o j o i n t h e e x p e d i t i o n . L a s t l y I s h o u l d l i k e t o t h a n k t h e o t h e r members o f t h e e x p e d i t i o n who h e l p e d i n many ways.
R e f e r e n c e s
Aronson, L.R. 1951. O r i e n t a t i o n and jumping b e h a v i o u r i n t h e g o b i i d f i s h , B a t h y g o b i u s s o p o r a t o r . Am. Mus. N o v i t . 1 4 8 6 , 1-22.
Aronson, L.R. 1971. F u r t h e r s t u d i e s o n o r i e n t a t i o n a n d jumping b e h a v i o u r i n t h e g o b i i d f i s h , B a t h y g o b i u s s o p o r a t o r . A n n . N . Y . A c a d . s c i . 1 8 8 , 378-392.
Beebe, W . a n d Tee-van, J . 1 9 3 3 . F i e l d book o f the shores f i s h e s o f B e r m u d a . New York and London: G.P. P u t n a m ' s S o n s . 337pp.
Rohlke, J.E. and C h a p l i n , C . C . G . 1 9 6 8 . Fishes o f the Bahamas a n d a d j a c e n t t r o p i c a l w a t e r s . Wynnewood, P e n n s y l v a n i a : L i v i n g s t o n P u b l i s h i n g Co. 771pp.
B r e d e r , C.M. 1948. O b s e r v a t i o n s on c o l o r a t i o n i n r e f e r e n c e t o
b c h a v i o u r i i , t i d e - p o o l and o t h e r m a r i n e s h o r e f i s h e s , B u l l . Am.
Plus. n a t . i i i s t . 9 2 , 281-312,
B r c d e r , C.M. 1954. F u r t h e r s t u d i e s on f a c t o r s i - n f l u e n c i n g t h e r e a c t i o n s o f t r o p i c a l s h o r e f i s h e s t o s h e l l s . Z o o l o g . i c a , N,Y 39, 79-83.
C h a p l i n , C . C . G . and S c o t t , P. 1 9 7 2 . F i s h w a t c h e r g u i d e t o West A t l a n t i c C o r a l R e e f s . Wynnewood, P e n n s y l v a n i a : L i v i n g s t o n P u b l i s h i n g Co.
6 5 ~ ~ .
Doty, M.S. 1957. Rocky I n t e r t i d a l S u r f a c e s . G e o l . S o c . Am. M e m o i r , 6 7 , p a r t 2 , 535-585.
D u a r t e - B e l l o , P , P . and B u e s a , R . J . 1 9 7 3 . C a t a l o g o d e Peces C u b a n o s ( P r i m e r a ~ e v i s i b n )
.
I . I n d i c e ~ a x b n o m i c o.
2 2 5 ~ . ; I I.
I n d i c e T a x b n o m i c o . l 7 7 p . ; 111. I n d i c e Nombres V u l g a r e s ; I n d i c e d e A u t o r e s ; ~ i b l i o g r a f j a y A p e n d i c e s.
l l 7 p . C i e n c i a s , La Habana,S e r . 8 , I n v e s t i g a c i o n e s M a r i n a s , Nos. 3 , 4 , 5 .
F i s h e l s o n , L . 1 9 6 3 . O b s e r v a t i o n s on t h e l i t t o r a l f i s h e s o f I s r a e l . I . B e h a v i o u r o f B l e n n i u s p a v o R i s s o ( T e l e o s t e i , B l e n n i i d a e )
.
I s r a e l J. Zool. 1 2 , 67-80,
G i b s o n , R.N. 1967. The u s e o f t h e a n a e s t h e t i c q u i n a l d i n e i n f i s h e c o l o g y . J. a n i m . E c o l . 3 6 , 295-301.
G i b s o n , R . N . 1 9 6 7 a . S t u d i e s on t h e movements o f l i t t o r a l f i s h . J . a n i m . E c o l . 36, 215-234.
G i b s o n , R . N . 1967b. E x p e r i m e n t s on t h e t i d a l rhythm o f B l e n n i u s p h o l i s . J . m a r . b i o l . A s s . U . K . 47, 97-111.
G i b s o n , R . N . 1969. The b i o l o g y and b e h a v i o u r o f l i t t o r a l f i s h . O c e a n o g r . Mar. B i o l . A n n . R e v . 7 , 367-410.
G o s l i n e , W.A. 1 9 6 5 . V e r t i c a l z o n a t i o n o f i n s h o r e f i s h e s i n t h e Upper Water L a y e r s o f t h e Hawaiian I s l a n d s . E c o l o g y , 4 6 , 823-831.
H i a t t , R.W. and S t r a s b u r g , D.W. 1 9 6 0 . E c o l o g i c a l r e l a t i o n s h i p s o f t h e f i s h f a u n a on c o r a l r e e f s o f t h e M a r s h a l l I s l a n d s . E c o l . Monogr. 30, 65-127.
L o n g l e y , W . H . a n d H i l d e r b r a n d , S . F . 1 9 4 1 . S y s t e m a t i c c a t a l o g u e o f t h e f i s h e s o f T o r t u g a s F l o r i d a w i t h o b s e r v a t i o n s i n c o l o r , h a b i t s a n d l o c a l d i s t r i b u - t i o n . P a p T o r t u g a s L a b . , 34 ( C a r n e g i e I n s t .
W a s h i n g t o n P u b l . 5 3 5 ) , 1 - 3 3 1 .
M i t c h e l l , D.F. 1 9 5 3 . An a n a l y s i s o f s t o m a c h c o n t e n t s o f C a l i f o r n i a t i d e p o o l f i s h e s . A m . M i d l . N a t . 4 9 , 862-871.
P o t t s , G.W. 1 9 7 9 . The z o n a t i o n o f r o c k y l i t t o r a l a r e a s a r o u n d L i t t l e Cayman ( W e s t I n d i e s ) . A t o l l R e s e a r c h B u l l e t i n , t h i s i s s u e . R a n d a l l , J . E . 1 9 6 8 . C a r i b b e a n R e e f F i s h e s : N e p t u n e C i t y , New J e r s e y
T.F.H. P u b l i c a t i o n s , I n c . 3 1 8 p p .
S t e p h e n s o n , T,A. a n d S t e p h e n s o n , A . 1 9 5 2 . L i f e b e t w e e n t i d e m a r k s i n N o r t h A m e r i a I1 N o r t h e r n F l o r i d a a n d t h e C a r o l i n a s , J , E c o l , 4 0 , 1-49,
1 9 5 0 h , Pa'itc-irn v a r i a b i l i t y a x o n y p o p u l a t i o n s o f t h e gobi:i.d f i - s h . B a t i ~ y g o b i u s s o p o r a t o r , C o p e l a , 1.950, 1 8 2 - 1 9 4 .
Thornson, D.A. z n d i e h n e r , C . E . 1 9 7 6 . g e s i s tence of a x G c ] - T - ' 1 i i l t e i - t l c 2 1 f i s h ~ o m m u r ~ i t y i n a p h y s i c a l l y u n s t a b l e e n v i r o n m e n t . J . e x p . m a r , B l o l . E c o l . 2 2 , 1 - 2 9 .
W i l l i a m s , G . C . 1 9 5 7 . Homing b e h a v i o u r o f C a l i f o r n i a r o c k y s h o r e f i s h e s . Univ. C a l i f . P u b l s . Z o o l . 5 9 , 249-84,
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F i g u r e 20. D i a g r a m o f ( a ) S p l a s h Zone and ( b ) S u r g e Z o n e p o o l s w i t h t h e i r t y p i c a l i n h a b i t a n t s : 1. E u c i n o s t o m u s a r g e n t e u s ; 2. B a t h y g o b i u s s o p o r a t o r ; 3 . A b u d e f d u f s a x a t i l i s ; 4 . L u t j a n u s a p o d u s ; 5. Gerres c i n e r e u s ; 6. T o m i c o d o n f a s c i a t u s ; 7 . A d i o r y x v e x i l l a r i u s ; 8 . E u p o m a c e n t r u s l e u c o s t i c t u s ; 9 . P u p e r i t a pupa;
10. A c e t a b u l a r i a s a n c t a e - c r u c i s ; 11. T h a l a s s o m a b i f a s c i a t u m ; 12. Diadema a n t i l l a r u m ; 1 3 . C a n t h i g a s t e r r o s t r a t a ; 1 4 . L i t t o r i n a m e s p i l l u n ; 15. E c h i d n a c a t e n a t a
