D. Michael Fry

Ingestion of plastic debris by Laysan Albatrosses and Wedge-tailed Shearwaters in the Hawaiian Islands

Surveys of Laysan Albatross and Wedge-tailed Shearwaters on Midway and Oahu Island, Hawaii, identified a high proportion of birds with plastic in the upper gastrointestinal tract, representing hazards to the health of adult birds and their chicks. Fifty Laysan Albatross chicks were examined for plastic items lodged within the upper digestive tract. Forty-five (90%) contained plastic, including 3 chicks having proventricular impactions or ulcerative lesions. Plastic items in 21 live albatross chicks weighed a mean of 35.7 g chick −1 (range 1–175 g). Four dead birds contained 14–175 g (mean 76.7 g). Two of four adult albatross examined contained plastic in the gut. Laysan albatross chicks have the highest reported incidence and amount of ingested plastic of any seabird species. Twelve of 20 adult Wedge-tailed Shearwaters (60%) contained plastic particles 2–4 mm in diameter. Impaction did not appear to be a significant hazard for adult shearwaters. Shearwater chicks were not examined. Chemical toxicity of plastic polymers, plasticizers and antioxidant additives is low, although many pigments are toxic and plastics may serve as vehicles for the adsorption of organochlorine pollutants from sea water, and the toxicity of plastics is unlikely to pose significant hazard compared to obstruction and impaction of the gut.

Production and release of acetylcholinesterase by cultured chick embryo muscle.

Abstract The acetylcholinesterase (AChE) activity of cultures from 11-day-old chick embryo muscle cells was studied for up to 4 weeks in vitro. AChE activity was found in mononucleated cells and multinucleated myotubes. The activity increased greatly after fusion. Maximum AChE levels were reached after 7–10 days of incubation and tended to decline thereafter. Multiple forms of AChE found in embryo muscle in situ were present in cultures before and after fusion. Selective inhibitors and substrates were used to show that AChE was released by the cells into their medium. Within a 2-day period the AChE that accumulated in the medium averaged over 6 times that remaining in the cells. Release of AChE from the cells was inhibited by cycloheximide, and AChE levels in cells and medium were much reduced when differentiation was inhibited by bromodeoxyuridine. Little AChE was present in subcultures of fibroblasts from muscle cultures. Acetyl-β-methylcholine and, to a lesser degree, choline itself, prevented the decrease in AChE levels of 2- to 3-week-old muscle cultures.

Pathology of Common Murres and Cassin's Auklets Exposed to Oil

The histopathology of diving seabirds exposed to oil is described. Cassins Auklets (Ptychoramphus aleuticus) were experimentally exposed to weathered Santa Barbara Channel (CA) crude oil by external application to the breast plumage or wings. Beached Common Murres (Uria aalge) were recovered from an accidental oil spill of bunker C fuel oil. Exposed birds exhibited hepatocellular dissociation and hemosiderosis, renal tubular necrosis, and hemolytic anemia. Both unexposed and exposed birds exhibited numerous gastrointestinal lesions and parasites making interpretation of oil damage effects to the gastrointestinal system difficult. Burrow nesting auklets had a high incidence of pneumoconiosis while cliff nesting murres had no particulate inclusions on lungs. The results describe the extent of pathology to be expected in wild, free living seabirds.

Survival and dispersal of oiled brown pelicans after rehabilitation and release

Abstract California brown pelicans (Pelecanus occidentalis californicus) were exposed to oil spills just prior to the 1990 breeding season and during the 1991 breeding season in the Southern California Bight (SCB); some were captured, rehabilitated (cleaned and given veterinary care) and released (total = 31 colour- and radio-marked + 81 colour-marked only; = RHB). Nineteen unoiled controls (= CON) from the SCB population, but from an unaffected area, were captured, radio-marked (11) and/or colour-marked (8) in 1990. Despite extensive surveys in the Gulf of California and western Baja California (latitude 23° to 30°N), all radio signals, recoveries and sightings were on the Pacific Coast between 30° and 47°N from 1990–1992. After release and until radio-telemetry data ceased to provide a complete sampling of RHB and CON (after about 6 months), RHB pelicans disappeared at a higher rate than CON; a continuing lower survival of RHB was also indicated from independent sightings of colour-marked pelicans by late 1992. RHB pelicans showed no breeding activity (or even presence or association with breeding colonies) in both years. In contrast, expected proportions of radio-marked CON pelicans were active at breeding colonies in 1990, and the general brown pelican population (which acted as controls in 1991) was active at breeding colonies in 1991. Post-breeding dispersal occurred as expected (mostly to the north) in 1990 and 1991 with CON. RHB pelicans remained sedentary in the SCB for at least 5–6 months in 1990 but dispersed north ahead of CON (as expected for non-breeders) in 1991, apparently in response to building ENSO (El Nino/Southern Oscillation) conditions in the SCB 1991–1992. RHB pelicans (1990) tended to remain farther away from the breeding colonies than CON (1990) in their second post-rehabilitation breeding season. At that time, their dispersal behaviour was similar to that expected for non-breeding adults and juveniles. We conclude that oil and/or rescue and treatment result in long-term injury to brown pelicans, and that current efforts do not restore them to breeding condition or normal survivability.

Reduced reproduction of wedge-tailed shearwaters exposed to weathered Santa Barbara crude oil

Wedge-tailed Shearwaters breeding on Manana Island, Hawaii were treated with 0.1–2.0 ml weathered Santa Barbara crude oil either by external application to the breast plumage or by oral dose in gelatin capsules approximately 30 days prior to egg laying. Applications of oil caused reduced lay, lowered hatching success, and reduced breeding success. Two ml applied externally to the breast plumage resulted in a greatly reduced number of eggs laid and complete hatching failure of 60 pair of exposed birds. Oral doses of oil in gelatin capsules reduced laying and breeding success, but to a lesser extent than external exposure. Oil exposure did not change the length of the prelaying exodus or cause birds to move to new areas of the breeding colony, but resulted in abandonment and reduced incubation attentiveness. Growth rates of chicks of oral dosed birds were not different from controls, although survival of chicks of dosed birds was reduced. Long-term effects of external application of 2.0 ml of oil were demonstrated by a decreased number of birds returning to the colony in the year after dosing and reduced breeding success one year after oil exposure.

Posthatch Oral Estrogen Exposure Impairs Adult Reproductive Performance of Zebra Finch in a Sex-Specific Manner

We determined whether short-term, posthatch oral exposure to estradiol benzoate (EB) or the industrial surfactant octylphenol (OP) could impair the reproductive performance of zebra finches. If so, naturally occurring phytoestrogens and xenoestrogens might influence reproduction in wild populations. Chicks were given oral administration of 10 or 100 nmol EB per gram of body mass (earlier work showed the latter to be the minimum oral dose required to maximally masculinize female song nuclei) or an equimolar amount of OP daily from 5 through 11 days of age. Canola oil was used as a vehicle and control. Reproductive testing was done either in individual pair cages or in communal cages that permitted self-selection of mates, N = 10 pairs per group. Pairs consisted of EB-treated males and females, EB-treated males paired with canola-treated females, vice versa, and canola-treated males and females. Posthatch EB treatment produced sex-specific impairments in reproduction that, in some instances, were additive when both sexes were treated. Egg production was reduced and egg breakage was increased in 100 nmol/g EB-treated male and female pairs. The incidence of missing eggs was increased in 10 nmol/g EB-treated male and female pairs. Candled fertility was reduced in both groups containing 100 nmol/g EB-treated males. The number of hatched chicks was severely reduced in all EB-treated groups. No adverse effects of OP treatment were detected. These significant treatment effects (all P < 0.05) show that posthatch EB treatment profoundly disrupts the reproductive performance of zebra finches, suggesting that exposure to estrogens in the wild could impair the reproductive performance of wild populations.

Oral Estrogen Masculinizes Female Zebra Finch Song System

It is well established that parenteral treatment of female zebra finch chicks with estradiol masculinizes their song control nuclei and that as adults they are capable of song. Concern over the widespread use of putative environmental estrogens caused us to ask whether oral exposure to estrogens (a natural route of exposure) could produce similar effects. We dosed chicks orally with estradiol benzoate (EB; 1, 10, 100, and 1000 nmol/g of body mass per day, days 5-11 posthatch), the non-ionic surfactant octylphenol (100 and 1000 nmol/g), or the pesticides methoxychlor (100 and 1000 nmol/g) and dicofol (100 nmol/g) and measured their song control nuclei as adults. EB treatment produced increases in song nuclei comparable to that induced by parenteral administration of estrogens. This is the first study of which we are aware to use an oral route of administration, which simulates the natural process of parent birds feeding their nestlings. We conclude that oral exposure to estradiol alters song control nuclei and we report in a related paper (Millam et al., 2001) that such exposure severely disrupts reproductive performance. Although we detected no influence of xenobiotics on induction of song control nuclei the possibility remains that oral exposure to xenoestrogens in high enough doses could affect development.

Metabolism and storage ofp,p′ dicofol in American kestrels (Falco sparverius) with comparisons to Ring Neck Doves (Streptopelia risoria)

Residues ofp,p′ dicofol,p,p′ dichlorobenzophenone (p,p′ DCBP),p,p′ dichlorobenzhydrol (p,p′ DCBH), 1,1-bis (4-chlorophenyl)-2,2-dichloroethanol (p,p′ DCD) and 1,1-bis (4-chlorophenyl)-2,2 dichloroethylene (p,p′ DDE) are reported in liver, fat, brain and oviducts of American kestrels exposed top,p′ dicofol. Breeding female kestrels were exposed to oral gavage dosages of 3.0 and 0.3 mg dicofol/kg body weight per day, equivalent to 1 or 10 mg dicofol/kg diet, for 39 days. Kestrels exhibited an eggshell thinning response similar to that produced by DDE, under these exposures. The major hepatic metabolite of dicofol in kestrels was DCD, but most organochlorine stored in tissues was in the form of dicofol. DDE was not a major metabolite of dicofol in kestrels. Compared with doves, kestrels had a significantly reduced metabolic capacity to transform dicofol to DCBP and DCBH, and had a steeper dose-response curve for dicofol-induced eggshell thinning.