Food selection and feeding behaviour of Baltic Sea mysid

0,59

MB

shrimps

35

stron

4423

ID

University of Helsinki

2001

rok

CONTENTS

INTRODUCTION . 6

Mysids – a link between lower trophic levels and fish 6

Pelagic mysids: Mysis mixta and M. relicta 8

Littoral mysids: Praunus flexuosus 8

Northern Baltic plankton community and food availability of mysids 9

Previous studies on the feeding of Baltic mysids . 9

Growth of mysids 11

Conceptual background 12

Optimal foraging theory . 12

Functional responses 12

Predation cycle 13

Trade-offs 14

OBJECTIVES OF THE STUDY 15

MATERIAL AND METHODS . 16

Study area 16

Sampling 17

Field studies . 18

Laboratory experiments 18

Statistical analyses and equations . 18

RESULTS AND DISCUSSION 19

Food utilisation during growth 19

C:N ratio . 21

Selective feeding . 22

Effects of environmental factors on feeding success 24

Abiotic factors: the effect of light . 24

Biotic factors: the effect of cyanobacteria 25

CONCLUSIONS . 26

ACKNOWLEDGEMENTS. 28

REFERENCES 29