North Patagonian Estuaries Appear to Function As Nursery Habitats for Marble Crab (metacarcinus Edwardsii)

Compared to other coastal habitats, estuaries are widely recognized to provide an important habitat for early stage crustacean development, such as recruitment, growth and survival. Thus, estuaries contribute to the reproductive population via the ontogenetic migration of mature crustaceans to other habitats. This study describes the spatial–temporal dynamics of the different ontogenetic stages of the Chilean marble crab (Metacarcinus edwardsii), the most harvested crab throughout Chile, in a northern Patagonian estuary. Crab traps were deployed monthly throughout the estuary and over a bathymetric gradient to evaluate the relative abundance of juveniles, pre-adults and adults. Crabs presented a clear segregated distribution dependent on ontogenetic stage, likely due to the migration of juveniles from the middle estuary to the outer section, which is associated with sexually mature individuals. Furthermore, a second bathymetric reproductive migration is identified for adults, characterized by a migration of mature individuals to deeper waters during winter and return to shallower waters during spring for mating. Understanding habitat use in exploited species, such as this marble crab, is crucial to effectively develop conservation and management strategies.