Bioaccumulation of persistent organic pollutants in female common dolphins (Delphinus delphis) and harbour porpoises (Phocoena phocoena) from western European seas: Geographical trends, causal factors and effects on reproduction and mortality

Abstract

High PCB levels were recorded in porpoises and common dolphins from European coasts. AbstractConcentrations of polychlorinated biphenyls (PCBs) in blubber of female common dolphins and harbour porpoises from the Atlantic coast of Europe were frequently above the threshold at which effects on reproduction could be expected, in 40% and 47% of cases respectively. This rose to 74% for porpoises from the southern North Sea. PCB concentrations were also high in southern North Sea fish. The average pregnancy rate recorded in porpoises (42%) in the study area was lower than in the western Atlantic but that in common dolphins (25%) was similar to that of the western Atlantic population. Porpoises that died from disease or parasitic infection had higher concentrations of persistent organic pollutants (POPs) than animals dying from other causes. Few of the common dolphins sampled had died from disease or parasitic infection. POP profiles in common dolphin blubber were related to individual feeding history while those in porpoises were more strongly related to condition.

Toothed whales in the northwestern Mediterranean: Insight into their feeding ecology using chemical tracers

“…However, organochlorine (OC) contaminants are less frequently used for dietary reconstruction, but they can allow for segregation of cetacean stocks (Borrell et al, 2006;Herman et al, 2005;Krahn et al, 2007;Pierce et al, 2008). OC accumulates through the food web and increases with the species trophic level (Hoekstra et al, 2003;Marsili and Focardi, 1996b;Ross et al, 2000;Weijs et al, 2009).…”

Cytochrome P450 1A1 expression in cetacean skin biopsies from the Indian Ocean

“…In marine mammals such as cetaceans, stable contaminants are reported to induce sensitivity to infectious diseases, such as in the harbour porpoise (Phocoena phocoena) from the North-east Atlantic with high PCBs level. Indeed, high PCB levels have been recorded in harbour porpoises dying from an infectious disease compared with individuals dying from other causes on animals stranded on the coasts of the UK, on the continental southern North Sea coast (Jepson et al, 2005;Pierce et al, 2008) and for the German North and Baltic Seas coasts (Beineke et al, 2005). Morbillivirus epizootics in the harbour seal (Phoca vitulina) and striped dolphin (Stenella coeruleoalba) populations have been suspected to be associated with high level of PCBs (Aguilar and Borrell, 1994;Hall et al, 1992).…”

“…In this study, contaminant concentrations were not investigated on the blubber. As pollutants induce the expression of CYP1A1 and as SA and SL are resident in the Mayotte waters all year-round, they could have been contaminated locally through the food by the process of bio-magnification (Pierce et al, 2008). Despite the fact that the southern hemisphere has a low level of pollution, some restricted areas such as river mouths or semi-closed water masses are contaminated as a result of point source pollution (Aguilar et al, 2002).…”

“…The expression could be induced by environmental contaminants that are also suspected to result in adverse health effects in cetaceans (Hall et al, 2006;Jepson et al, 2005;Pierce et al, 2008). Further investigations will be helpful to identify the contaminants, their concentrations and to evaluate the potential consequences from an animal health standpoint.…”

“…These contaminants present worldwide and in all oceans, accumulate in the marine food web. High concentrations accumulate in the tissues of marine top predators, such as the blubber of marine mammals (Aguilar et al, 2002;Pierce et al, 2008). In addition, these stable contaminants are suspected to have adverse health effects mostly in marine top predators, especially on the immune and reproductive systems (Hall et al, 2006;Reijnders, 1986).…”