CONTENTS 



I. INTRODUCTION ' 



II. METHODS AND DEFINITIONS 2 



A. Methods and Materials 2 



B. Definitions 2 



1. Bluefin Tuna 2 



a. Length - 



b. Weight 3 



2. Size-Age Groups 3 



3. Trap Fishery Terminology 3 



III. AGE AND GROWTH 5 



A. Introduction -^ 



8. Methods of Determining Age and Growth and 

 Their Application to Bluefin Tuna 5 



1. Size Frequencies ^ 



2. Counts of Marks on Hard Parts 5 



a. Scales ^ 



b. Vertebrae 6 



c. Otoliths ^ 



3. Release-Recapture Data for Tagged Fish 8 



C. Results ^ 



1. Sizes of Fish at Determinable Ages 8 



2. Growth of Bluefin Tuna in Its First Year 



of Lift 9 



3. Growth of Young Bluefin Tuna 1 1 



4. Seasonal Changes in the Length- Weight 

 Relationship of Large Bluefin Tuna 12 



5. Differential Growth of Males and Females 13 



6. Ultimate Length '3 



7. Discussion '^ 



IV. DISTRIBUTION AND FISHERIES 15 



A. General Distribution '5 



B. Development of the Major Fisheries 15 



C. Distribution and Fisheries by Areas 18 



1. Introduction '^ 



2. Western Atlantic '8 



a. Newfoundland to Cape Cod 1 8 



i. Newfoundland '8 



ii. Gulf of St. Lawrence 19 



iii. Nova Scotia '9 



iv. Cape Cod to Maine 22 



b. Cape Hatteras - Cape Cod 



(Coastal Waters) 25 



c. Atlantic Ocean Outside 200 Meter Contour 



N of 35°N and W of 40''W 27 



d. Bahamas and Southeastern Florida 27 



e. Gulf of Mexico and Caribbean Sea 29 



3. Atlantic Oceanic Waters 29 



4. Eastern Atlantic Islands 34 



a. Azores 34 



b. Madeira 35 



c. Canary Islands 35 



5. Eastern Atlantic 36 



a. Northeastern Atlantic 37 



b. Norway -'' 



c. North Sea 38 



d. Bay of Biscay 39 



e. West Coast of Portugal 42 



f West Coast of Morocco 42 



g, I bero- Moroccan Bay Trap Fisheries 42 



h. Trends in Eastern Atlantic Fisheries 46 



6. Mediterranean and Black Seas 46 



a. Western Mediterranean 48 



b. Central Mediterranean 53 



c. Eastern Mediterranean and Black Sea 63 



d. Summary ^^ 



V. SPAWNING 68 



A. Introduction ^° 



B. Definitions 68 



C. Criteria for Determining Seasons and Areas 



of Spawning, and Their Limitations 68 



1. Presence of Ripe Adults 68 



2. Presence of Pelagic Eggs and Larvae 69 



D. Spawning Areas and Seasons 70 



1 . Mediterranean and Black Seas 70 



a. General Information 70 



b. Specific Occurrences 70 



2. Eastern and Central North Atlantic and the 

 South Atlantic 72 



a. General Information 72 



b. Specific Occurrences 73 



3. Western North Atlantic 80 



a. General Information 80 



b. Specific Occurrences 80 



E. Relationships Between Environmental Factors 



and Spawning Behavior 84 



1 . Introduction ^4 



2. Mediterranean Sea 86 



3. Eastern Atlantic 87 



a. Distribution, Objectives and Nature of 

 Research 87 



b. Portugal 88 



c. Spain 88 



d. Morocco 90 



e. Other Eastern Atlantic Areas 91 



