Effects of food deprivation state on feeding behavior and gastric evacuation of rock crabs, Cancer irroratus, during hypoxia

ABSTRACT

Climate change and anthropological activities have led to an expansion of hypoxia into the natural habitat of Cancer irroratus. In this study, we examined the effects of hypoxia and food deprivation state on food intake and subsequent gastric processing. Three different techniques were used to measure food intake. The gravimetric analysis of dry food pellets was the most accurate method. In severe hypoxia (20% oxygen), rock crabs reduced food intake, and more crabs refused to eat. Compared with fasted crabs, more starved crabs tended to eat in severe hypoxia. Subsequently, prolonged gastric emptying times paralleled the previously measured postprandial oxygen consumption in hypoxia. Starved crabs also exhibited slightly longer transit times for digesta compared with fasted crabs. These results suggest that although a trade-off may occur in starved rock crabs between the need to procure nutrients and deal with hypoxic stress, impaired digestive processing may still deleteriously affect these animals.

KEYWORDS:

• Crustacean
• digestive system
• gravimetric analysis
• radiographic analysis
• starvation
• X-ray

Acknowledgments

We wish to thank Roy Murphy, Sarah Nancollas and Evgeni Matveev for help with collection of crabs.

Disclosure Statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was funded by a Natural Sciences and Engineering Research Council, Discovery grant to IJM (207112) and a grant of Mitacs Accelerate (IT26355) and China Scholarship Council (201404910484) to Q; Natural Sciences and Engineering Research Council of CanadaNatural Sciences and Engineering Research Council of Canada [207112];