Preliminary Report on the Sperm Whale Data Collected During the Voyage of the Odyssey

Ocean Alliance (OA) launched the Voyage of the Odyssey (VOO) in response to growing concern about the impact of chemical pollution in the marine environment. The Voyage of the Odyssey is a five-year global effort designed to gather a baseline dataset on levels and potential effects of synthetic contaminants in all of the world’s oceans. The sperm whale (Physeter macrocephalus) was chosen as a bio-indicator species for the program. Lipophilic contaminants are likely to accumulate and biomagnify in sperm whales due to their high body fat content, their relatively long life span and their high trophic position within marine food webs. Moreover, because sperm whales have a global geographical distribution, a worldwide dataset can be collected from this one species. In addition to our toxicological studies, we are also collecting material and data for sperm whale genetics and acoustic analyses. The specific aims of the VOO program and the relevance of these aims to the International Whaling Commission (IWC) Scientific Committee’s efforts at making an in-depth assessment of sperm whales are summarized. OA methodologies for biopsy collection and sub-sampling and the current status of our data collection and analyses are presented. Introduction The oceans are considered the final sink for many toxicants and there is a growing concern about the impact of chemical pollution in the marine environment and its potential effects on the health of animals, plants and humans. Lipophilic contaminants, such as dichlorodiphenyltrichloroethanes (DDTs), polychlorinated biphenyls (PCBs) and other organochlorines (OCs), are known to accumulate in animal species including fish and marine mammals (Colborn and Smolen, 1996; Jorgenson, 2001). Many of these compounds have been shown to adversely effect laboratory animals and wildlife (Safe, 1984; Colborn et al., 1993). Much research effort is dedicated to understanding the potential links between chemical exposure and altered immune and reproductive systems, impaired physiological and endocrine functions as well as neurobehavioural disorders in traditional animal models (rodents) and certain wildlife species (Fry and Toone, 1981; Beard and Rawlings, 1998; Hany et al., 1999; Guillette et al., 2000; Fox, 2001). However, scientific understanding of the effects of environmental pollution in marine mammals remains limited (Reijnders, 1986; Beland et al., 1993; Ross et al., 1996; Ross, 2000; Martineau et al., 2002). Ocean Alliance launched the Voyage of the Odyssey (VOO) to address the need for a globally integrated dataset allowing a consistent analysis of exposure to, and potential effects of, persistent organochlorines in marine life worldwide. Many marine mammals harbour large fatty reserves in their body where high levels of organochlorines and other lipophilic contaminants can accumulate (Aguilar and Borrell, 1994; Colborn and Smolen, 1996; Ross et al., 2000). Marine mammals are also subject to bioaccumulation and biomagnification of these fat soluble contaminants due to their relatively long life span and their high trophic position within marine food chains (Boon et al., 1992). Marine mammals therefore can be considered environmentally relevant candidates for use as sentinel species when assessing marine pollution (Ross, 2000). Sperm whales were selected as the study species for the VOO program due to their high trophic position and their widespread geographical distribution and because they can be acoustically tracked. Over 700 sperm whale skin and blubber biopsies have already been collected during the Voyage of the Odyssey. Analyses of concentration burdens, exposure and the molecular effects of bio-persistent toxicants in these biopsies are presently underway. Induction of the cytochrome P4501A1 enzyme (CYP1A1), which plays a critical role in the metabolism of planar halogenated and polycyclic aromatic hydrocarbons, is widely used as a biomarker of exposure to contaminants in many animal species (Stegeman et al., 1992). The toxicological component of the VOO program is designed to investigate CYP1A1 (and other CYP1) protein and gene expression in sperm whales using immunohistochemistry, enzyme, and gene expression assays. For each biopsy sample, additional analyses including genetic and stable isotopes studies will provide a comprehensive framework for the interpretation of the toxicology data. Specific Aims of the VOO Program and Relevance to Sperm Whale Assessment: 1. Provide samples to current researchers and establish an archive of samples from whales, squid, and pelagic fish living in the major ocean basins of the world. As new techniques or scientific questions arise, material from this archive will be made available to outside researchers. 2. Establish a biopsy sub-sampling protocol providing concurrent collection and storage of sub-samples for each biopsy, thereby maximizing the magnitude of information and data collected and potentially reducing the need for future re-sampling. 3. Conduct contaminant burden analyses of sperm whale samples with an emphasis on persistent organohalogens that are implicated in immunosuppression, altered endocrine and reproductive systems, cancer, and various pathologies in laboratory animals. 4. Conduct contaminant burden analyses of other biological samples (squid, fish) to examine biomagnification processes of other species in the food pyramids in which sperm whales feed. 5. Conduct analyses of biopsy samples for levels of CYP1A1. CYP1A1 can be used as a biomarker of exposure to environmental contaminants, such as persistent planar halogenated aromatic hydrocarbons and non-persistent polycyclic aromatic hydrocarbons. 6. Adapt toxicological assays and biomarkers developed in laboratory animals to marine mammal species. Examples include specific gene cloning, quantitative RT-PCR of CYP1A1 gene expression and assessment of cytochrome P450 1B1 (CYP1B1). 7. Compare data obtained with contaminant and biomarker analyses in order to investigate and potentially characterize the direct links between the two approaches and to validate and refine such techniques.