Legacy and contemporary persistent organic pollutants in North Pacific albatross

Sea turtle egg yolk and albumen as biomonitoring matrices for maternal burdens of organic pollutants

To establish the use of eggs as biomonitoring tools for maternal body burdens, we investigated the mother-to-egg ratio of 56 PCB, 12 OCP and 34 PBDE unique compounds from maternal plasma into replicate egg yolk and albumen samples in the loggerhead turtle (Caretta caretta) as a case study of a threatened migratory marine species. We applied robust Regression on Order Statistics to fully account for the information in both censored and uncensored data. Our results added new insights into the use of yolk as a suitable biomonitoring matrix; the difference between yolk and albumen which were previously analysed as a homogeneous mixture; and the value of accounting for censored data. Overall, compound-specific mother-to-egg ratios need to be considered when translating yolk levels back to maternal pollution burdens, and when assessing the risk to the subsequent generations of turtle embryos.

Sexual Dimorphism and Foraging Trips of the Laysan Albatross (Phoebastria immutabilis) on Guadalupe Island

Simple Summary

We evaluated the existence of sexual dimorphism in Laysan albatross from Guadalupe Island. Males were larger than females across all the morphological variables analyzed. We created a sex predictor model for Laysan albatross individuals that requires a minimum number of input variables and will considerably reduce the handling times and field costs of future studies. Laysan albatross foraging trips were recorded during their breeding season over multiple years and no significant differences were found between the distances travelled by males versus females.

Abstract

Sexual dimorphism in the Laysan albatross (Phoebastria immutabilis) on Guadalupe Island was evaluated during the breeding seasons of 2015–2018 by measuring and comparing 10 morphological attributes: cranial length, bill length, nostril length, cranial width, bill height, bill width, tarsus length, closed wing length, opened wing length, and wingspan length in reproductive adults (n = 135). Males were larger than females across all traits (Student’s t-test, p < 0.05, p < 0.05). We created a logistic model using stepwise regression to predict sex based on morphological variables. This model indicated four significant morphological predictor variables (z < 0.05) and was able to successfully predict the sex of P. immutabilis individuals in more than 90% of the cases. Based on these predictor variables, a web app was developed to determine the sex of the Laysan albatross in the field, providing a non-invasive method for rapid data collection that reduces costs and handling times while improving conservation efforts. We tracked Laysan albatross (n = 36) during breeding seasons and found no significant differences between females and males for either trip length (GLMM, F = 0.017, DF = 1, 1, p = 0.917 > 0.05) or maximum trip distance (GLMM, F = 0.374, DF = 1, 1, p = 0.651 > 0.05). Our results suggest that both sexes show a strong preference to travel to highly productive coastal waters northeast of the breeding colony that are influenced by the California Current. The present research will serve to establish a baseline to protect this species on Guadalupe Island and highlights the importance of understanding sexual dimorphism in at-risk seabird species.

Wandering albatrosses document latitudinal variations in the transfer of persistent organic pollutants and mercury to Southern Ocean predators

Top marine predators are effective tools to monitor bioaccumulative contaminants in remote oceanic environments. Here, we used the wide-ranging wandering albatross Diomedea exulans to investigate potential geographical variations of contaminant transfer to predators in the Southern Ocean. Blood concentrations of 19 persistent organic pollutants and 14 trace elements were measured in a large number of individuals (N = 180) of known age, sex and breeding status from the subantarctic Crozet Islands. Wandering albatrosses were exposed to a wide range of contaminants, with notably high blood mercury concentrations. Contaminant burden was markedly influenced by latitudinal foraging habitats (inferred from blood δ(13)C values), with individuals feeding in warmer subtropical waters having lower concentrations of pesticides, but higher concentrations of mercury, than those feeding in colder subantarctic waters. Sexual differences in contaminant burden seemed to be driven by gender specialization in feeding habitats, rather than physiological characteristics, with females foraging further north than males. Other individual traits, such as adult age and reproductive status, had little effect on blood contaminant concentrations. Our study provides further evidence of the critical role of global distillation on organic contaminant exposure to Southern Ocean avian predators. In addition, we document an unexpected high transfer of mercury to predators in subtropical waters, which merits further investigation.

Detection of nonylphenol and persistent organic pollutants in fish from the North Pacific Central Gyre

Despite scientific and public concern, research on food web contamination from chemicals in plastic is limited, and distinguishing plastic sources from prey remains a challenge. We analyzed juvenile yellowtail (Seriola lalandi) from the North Pacific Central Gyre for plastic ingestion and tissue concentrations of persistent organic pollutants and nonionic surfactants to investigate potential contamination from plastic exposure. Ingestion of synthetic debris occurred in ~10% of the sample population. PCBs and DDTs were 352±240 (mean±SD) and 1425±1118 ng/g lw, respectively. PBDEs were 9.08±10.6 ng/g lw, with BDEs-47, 99, and 209 representing 90% of PBDEs. Nonylphenol (NP) was detected in one-third of the yellowtail with a mean of 52.8±88.5 ng/g ww overall and 167±72.3 ng/g ww excluding non-detects. Because environmental NP is strongly associated with wastewater treatment effluents, long-range transport is unlikely, and NP was previously measured in gyre plastic, we concluded that plastic-mediated exposure best explained our findings of NP in yellowtail.