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ABSTRACT
An i n t e r t i d a l p o p u l a t i o n o f t h e anaspidean ~ p l y s i a ' d a c t y l o m e l a Rang was followed f o r t h r e e c o n s e c u t i v e y e a r s a t t h e Leigh Marine Reserve, North Auckland, New Zealand.
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F i e l d a s s e s s m e n t s were m d e o f r e c r u i t m e n t , growth (by r e c a p t u r e o f tagged i n d i v i d u a l s ) , d e n s i t y , c r a w l i n g r a t e , gonad i n d e x and m o r t a l i t y . These d a t a allowed n v n t h l y e s t i m a t e s o f t h e e n t i r e p o p u l a t i o n w i t h i n t h e e n t i r e s t u d y a r e a (2.76 h a ) to be made. Complexnentary l a b o r a t o r y s t u d i e s i n v e s t i g a t e d a c c e p t a b l e f o o d s and a n energy budget i n c l u d i n g d a t a o n e n e r g y o f t h e food, growth r a t e s , e g e s t i o n , r e s p i r a t i o n and a s s i m i l a t i o n e f f i c i e n c y were a l s o o b t a i n e d i n t h e l a b o r a t o r y . I n c o n j u n c t i o n w i t h t h e s e s t u d i e s , f i e l d work on t h e a l g a l food o f
5.
dactylomela ( s p e c i e s o f Laurencia) e l u c i d a t e d t h e e n t i t i e s p r e s e n t , t h e i rs e p a r a t e y e a r l y changes i n biomass and t h e c a u s e s . F r o m this i n f o r m a t i o n , d a t a o n f w d r e q u i r e m e n t s f o r
5.
dactylomela.ha-l.nvnth-l a r e c o n t r a s t e d with s t a n d i n g c r o p e s t i m a t e s f o r L a u r e n c i a spp. i n t h e same u n i t s to p e r m i t c o n s i d e r a t i o n o f t h e t h e o r e t i c a l g r a z i n g e f f e c t s ofA.
dactylomela. S e v e r a l l i n e s o f e v i d e n c e show t h i s environment t o be sub- o p t i m a l f o r5.
dactylomela. Storms a c c o u n t f o r t h e g r e a t e s t n v r t a l i t y . b u t some l o s s e s a r e due t o p r e d a t i o n by t h e a s t e r o i d C o s c i n a s t e r i a s c a l a m a r i a (Gray). Few i n d i v i d u a l s r e a c h r e p r o d u c t i v e m a t u r i t y and t h e p o p u l a t i o n i s n o t s e l f - r e c r u i t i n g .An i n t e r t i d a l p o p u l a t i o n o f a second o p i s t h o b r a n c h , t h e Cephalaspidean Haminoea z e l a n d i a e (Gray i n D l c f f e n h c h ) was followed f o r t h r e e c o n s e c u t i v e a t M t u k a r a k a I s l a n d , Hauraki G u l f , New Zealand. F i e l d d e t e r m i n a t i o n s o f p o w t h , a n n u a l abundance and r e p r o d u c t i v e c y c l e s were m d e . The cryptogamic f l o r a a t m t u k a r a k a I s l a n d h a s been c h a r a c t e r i s e d and annual p a t t e r n s o f c o v e r and d i s t r i b u t i o n p r e s e n t e d f o r f i v e n n j o r s e a s o n a l components. The r e l a t i o n s h i p between Haminoea z e l a n d i a e and t h e s e a l g a e i s c o n s i d e r e d .
A d d i t i o n a l s t u d i e s on two l e s s - c o m o n a n a s p i d e a n s were c a r r i e d o u t . F i e l d d a t a o n b r e e d i n g , growth and d e n s i t y are g i v e n f o r 3 l y s i a p a r v u l a W r c h which e x i s t s i n s e p a r a t e , s p a t i a l l y - i s o l a t e d i n t e r t i d a l and s u b t i d a l p o p u l a t i o n s a t Goat I s l a n d Bay. f o r t h e s e two p o p u l a t i o n s d i f f e r e n c e s e x i s t i n d i e t , c o l o u r a t i o n , s i z e d i s t r i b u t i o n , growth and s u r v i v o r - s h i p . The i n t e r t i d a l h a b i t a t i s marginal whereas t h e s u b t i d a l is c l o s e to being o p t i m a l . B u r s a t e l l a l e a c h i i B l a i n v i l l e shows v a r i a b l e a n n u a l r e c r u i t m e n t to t h e cyanophyte Lyngbya majuscula i n t e r t i d a l l y a t Motdcaraka I s l a n d . Growth r a t e s have been d e t e r m i n e d f o r f i e l d and l a b o r a t o r y p o p u l a t i o n s . I n t h e f i e l d a d e l i b e r a t e o f f s h o r e m i g r a t i o n t a k e s p l a c e w h i l s t L_. majuscula i s still abundant. S p e c u l a t i o n s o n t h e p o s s i b i l i t i e s and c a u s e s f o r m i g r a t i o n s amongst o p i s t h a b r a n c h s a r e d i s c u s s e d .
A taxonomic r e v i s i o n o f t h e New Zealand Anaspidea f o l l w s a s a n appendix. T h e r e a r e e i g h t s e a h a r e s a u t h e n t i c a l l y recorded f o r New Zealand: Aplysia ( P r u v o t a p l y s i a ) p a m u l a March 1863;
A. ( V a r r i a ) dactylomela Rang 1828:
A.
(V.) k e r a u d r e n i Farig 1828;1.
(V.) e x t r a o r d i n a r i a ( A l l a n-
1932) ;
&.
( A p l y s i a ) j u l i a n a (Quoy & Gaimard 1832) 1 P u l s a t e l l a l e a c h i i B l a i n v i l l e 1817;S t y l o c h c i l t i s longicnuda (Quoy & G a i m r d 1825); D o l a b r i f c r n d o l a b r i f e r a (Cuvier 1817). F o r e a c h s p e c i e s a complete synonymy is g i v e n a s w e l l a s i u l l d e s c r i p t i o n , l o c a l i t y r e c o r d s and d i s c u s s i o n .
