FELIPPE ALDERT POSTUMA Population biology and behavioural aspects of the squid Doryteuthis plei (Blainville, 1823) in the northern coast of São Paulo, with emphasis on reproduction and feeding Thesis. submitted to the Oceanographic Institute of the University of São Paulo, in partial fulfilment of the requirements for the degree of Doctor of Sciences in Biological Oceanography Supervisor : Prof. Dr. Maria de los Angeles Gasalla São Paulo 2015 University of São Paulo Oceanographic Institute FELIPPE ALDERT POSTUMA Population biology and behavioural aspects of the squid Doryteuthis plei (Blainville, 1823) in the northern coast of São Paulo, with emphasis on reproduction and feeding Thesis submitted to the Oceanographic Institute of the University of São Paulo, in partial fulfilment of the requirements for the degree of Doctor of Sciences in Biological Oceanography CORRECTED VERSION i SUMMARY SUMMARY ................................................................................................................................................. I FIGURE INDEX...................................................................................................................................... III TABLE INDEX....................................................................................................................................... VII AGRADECIMENTOS ............................................................................................................................ XI ABSTRACT .......................................................................................................................................... XIII RESUMO ...............................................................................................................................................XIV GENERAL INTRODUCTION ................................................................................................................. 2 CHAPTER 1 - REPRODUCTIVE ACTIVITY OF THE TROPICAL ARROW SQUID DORYTEUTHIS PLEI AROUND SÃO SEBASTIÃO ISLAND (SE BRAZIL) BASED ON A 10- YEAR FISHERIES MONITORING. ....................................................................................................... 6 1. INTRODUCTION ............................................................................................................................... 7 2. MATERIALS AND METHODS ............................................................................................................ 8 2.1. Study area ............................................................................................................................. 8 2.2. Squid sampling ..................................................................................................................... 9 2.3. Processing of samples .......................................................................................................... 9 2.4. Reproductive structures ...................................................................................................... 10 3. RESULTS ....................................................................................................................................... 12 3.1. Population structure of squid D. plei caught by the São Sebastião Island small-scale fishery….. .......................................................................................................................................... 13 3.2.1. Females ........................................................................................................................................ 16 3.2.2. Males ............................................................................................................................................ 22 4. DISCUSSION .................................................................................................................................. 23 5. CONCLUSIONS AND SUMMARY ...................................................................................................... 27 CHAPTER 2 - ETHOGRAM ANALYSIS REVEALS NEW BODY PATTERNING BEHAVIOUR OF THE TROPICAL ARROW SQUID DORYTEUTHIS PLEI OFF THE SÃO PAULO COAST . 29 1. INTRODUCTION ............................................................................................................................. 30 2. MATERIALS AND METHODS .......................................................................................................... 32 2.1. Animal capture ................................................................................................................... 32 2.2. Experimental tank setup ..................................................................................................... 32 2.3. Animal care and husbandry ................................................................................................ 33 2.4. Experimental methods ........................................................................................................ 35 3. RESULTS ....................................................................................................................................... 36 3.1. Ethogram ............................................................................................................................ 37 3.1.1. Locomotors components .............................................................................................................. 38 3.1.2. Chromatic components ................................................................................................................. 39 3.1.3. Postural component ...................................................................................................................... 49 3.2. Body patterning .................................................................................................................. 50 3.2.1. Chronic patterns ........................................................................................................................... 50 3.3. Reproductive behaviour ...................................................................................................... 51 3.3.1. Acute patterns ............................................................................................................................... 51 4. DISCUSSION .................................................................................................................................. 54 5. CONCLUDING REMARKS ................................................................................................................ 59 CHAPTER 3 - ONTOGENETIC, SEXUAL, AND SPATIAL-TEMPORAL SHIFTS IN THE DIET OF THE SQUID DORYTEUTHIS PLEI OFF SÃO SEBASTIÃO REGION, SE BRAZIL. ............. 62 ii 1. INTRODUCTION ............................................................................................................................. 63 2. MATERIAL AND METHODS ............................................................................................................. 64 2.1. STUDY AREA ............................................................................................................................ 64 2.2. Squid sampling ................................................................................................................... 65 2.3. Data analysis ...................................................................................................................... 66 2.4. Maintenance and observations of squid in laboratory. ...................................................... 68 3. RESULTS ....................................................................................................................................... 69 3.1. Diet composition of Doryteuthis plei .................................................................................. 69 3.1.1. Feeding model of females............................................................................................................. 71 3.1.2. Feeding of males .......................................................................................................................... 74 3.2. Spatial and temporal patterns in the diet ............................................................................ 76 3.3. Feeding behaviour of Doryteuthis plei in laboratorial condition ....................................... 81 4. DISCUSSION .................................................................................................................................. 82 5. CONCLUSION ................................................................................................................................ 86 CHAPTER 4 - HUNTING BEHAVIOURS IN NEWLY-HATCHED PARALARVAE OF DORYTEUTHIS PLEI IN EXPERIMENTAL CONDITIONS. ........................................................... 89 1. INTRODUCTION ............................................................................................................................. 90 2. MATERIALS AND METHODS .......................................................................................................... 91 2.1. Collection and rearing ........................................................................................................ 91 2.2. Food of Doryteuthis plei ..................................................................................................... 92 2.3. Record and analysis of behaviours ..................................................................................... 93 3. RESULTS ......................................................................................................................................