Diet of coastal black shags ( Phalacrocorax carbo )
|Title||Diet of coastal black shags ( Phalacrocorax carbo )|
|Publication Type||Journal Article|
|Year of Publication||2004|
|Authors||McKinnon, HL, Fordham, RA, Lalas, C|
|Type of Article||paper|
|Keywords||Black Shag, diet., great cormorant, New Zealand, Phalacrocorax carbo|
The diet of black shags (Phalacrocorax carbo) at Pencarrow, New Zealand, during April – October 1999 is described from otoliths, jawbones and pharyngeal tooth plates found in 119 regurgitated pellets of adults and four stomachs and two regurgitations of chicks. Black shags were primarily marine foragers, with only one freshwater item, crayfish (Paranephrops planifrons) among 420 food items identified. Half of the diet comprised spotty (Notolabrus celidotus), but in total, 22 species were found in the pellets, including 17 fish species. The size of fish otoliths indicated significant differences in the length of the 11 most frequently occurring fish species. These ranged from an estimated length of 106 mm to 275 mm (mean length 220 mm) and were similar to those reported from other NZ studies. The mean length of fish taken by adults in winter was smaller compared with those in autumn and spring.