ABSTRACT

Development, morphology, and biology of king crab larvae have been of interest to scientists as long as they have been studying the species. The shape and form of larvae are useful for understanding their phylogenetic relationships and for many years were the only tools for this purpose (see McLaughlin, Chapter 2). In addition, morphological descriptions help to understand the function of various appendages and how they are used in nature. Meristic characteristics, that is, those that can be counted (such as spines and setae), are extremely useful for distinguishing species, as are ratios of morphological characters such as carapace length (CL) and rostral spine length. The biology and behavior of larvae are of great interest in order to understand how they function and survive in the plankton community and how they transition to postlarval life. Knowledge of the relationships

8.1 Introduction .................................................................................................................................. 233 8.2 Larval Development and Morphology ......................................................................................... 234

8.2.1 Larvae of Red King Crab, Paralithodes camtschaticus ................................................. 234 8.2.2 Blue King Crab, Paralithodes platypus .......................................................................... 239 8.2.3 Golden King Crab, Lithodes aequispinus ....................................................................... 240 8.2.4 Other King Crabs, Variations, and Exceptions ............................................................... 241

8.3 Growth and Development Patterns .............................................................................................. 241 8.3.1 Growth as a Function of Temperature ............................................................................. 242 8.3.2 Length and Weight of Larvae .......................................................................................... 244

8.4 Physiological Ecology of Larvae ................................................................................................. 244 8.4.1 Feeding and Nutrition ...................................................................................................... 244

8.4.1.1 Feeding Zoeal Stages ....................................................................................... 244 8.4.1.2 Nonfeeding Glaucothoe Stage ......................................................................... 246 8.4.1.3 Nonfeeding Zoeal Stages ................................................................................. 246 8.4.1.4 Lipids and Fatty Acids in Larval Nutrition ..................................................... 247

8.4.2 Effects of Temperature and Salinity on Survival ............................................................ 248 8.4.3 Oxygen Consumption ...................................................................................................... 250

8.5 Vertical Distribution and Density of King Crab Larvae ...............................................................251 8.6 Behavior of King Crab Larvae ..................................................................................................... 253

8.6.1 Phototaxis, Geotaxis, and Rheotaxis .............................................................................. 254 8.6.2 Vertical Migrations and Feeding Patterns ....................................................................... 254

8.7 Summary ...................................................................................................................................... 255 Acknowledgments .................................................................................................................................. 256 References .............................................................................................................................................. 256

recruitment processes (this topic is covered in detail by Loher, Chapter 18). Studies on food sources, feeding behavior, and environmental requirements are critical for the development of cultivation and stock enhancement programs, covered in detail in Chapter 13. This chapter begins with descriptions of the larvae of various species of king crabs, followed by discussions of feeding, growth, physiological ecology, and factors affecting growth and survival. The postlarval, or glaucothoe, stage is discussed only with regard to those characteristics that represent extensions of the planktonic larval phase; its function and behavior as a transitional stage between the planktonic larva and benthic juvenile are discussed by Stevens in Chapter 9.