Biology and bioaccumulation of PCBs in Tufted Puffins (Lunda cirrhata) of the northern North Pacific

Abstract

Ecological and morphological characteristics of the Tufted Puffin (Lunda cirrhata) in the pelagic northwestern Pacific Ocean were determined. Using these characteristics the bioaccumulation of polychlorinated biphenyls (PCBs) was investigated.
The average distribution density of Tufted Puffins was 0.95 birds•km^-2 in the entire northwestern North Pacific during the summer season. The birds occurred within the range of water temperatures from 2.0 to 12.0°C.
Morphological measurements of bills were larger in males than in females. For example, if the gape length was longer than 44.0mm there was a 72.5% chance that the birds would be male. Based on the changes of measurements with increasing number of bill furrows, Tufted Puffins were divided into three growth stages: young, subadult, and adult.
Most of the tissues and organs of males were generally heavier than females. This difference was more significant in the skeletal and muscular systems than visceral organs. The percentage of the skeletal system to body wight was larger in adults than in subadult for male, but larger in subadult than in youngs for females, indicating a difference in growth pattern between sexes.
Tufted Puffins were found to feed mainly on squid and fish. Consumption of other prey such as euphausiids and amphipods was largely confined to adults in the Bering Sea. Squid were available in any study sea area from April to July to all growth stages. On the contrary fish were consumed in the south of Aleutian Islands from April to July by youngs but in April and May by adults.
The mean concentrations of PCBs and DDE were 270 and 170 ng/g respectively, on a wet weight basis. The mean body burden of each chemicals were 160 and 100μg. There was high positive correlation (r=0.818) between the concentrations of PCBs and DDE in the sampled birds. This suggested that both pollutants had a similar distribution within the habitat of the Tufted Puffin. Concentrations of PCBs and DDE did not vary between growth stages, indicating that equilibrium concentrations of both chemical groups were attained at an early life stage.
Sixty four PCB components, mainly penta and hexachlorobiphenyls were detected. The combined concentration of MC (3-methylcholanthrene) and NM (non-metabolizable) type PCBs accounted for 75% of total PCB concentration, while the PB (phenobarbital) type PCBs accounted for only 9.5%. These compositions indicated a high activity of the PB type enzyme system in this species. Percentages of MC and NM type PCBs were higher in females than in males, a difference which could be explained by the difference in growth pattern between sexes. The MC type PCBs decreased with growth, suggesting that the activity of MC type enzyme system was higher in adults and/or that feeding habits altered with growth stages.
Sampled birds were divided into fatty or lean groups depending on nutritional conditions. The concentration and percentage of PB type PCBs were higher in fatty birds while the percentage of NM type PCBs was higher in lean birds. These trends suggested that the feeding activity was higher in fatty birds, whereas enzymatic activity of the PB type enzyme system was higher in lean birds.