Michael Warren of the AP has this up on a disturbing story of whales being attacked by seagulls.
I’m concerned that the seagulls, since they are feeding on fish, perhaps are exhibiting such bizarre behavior because of mercury. It’s a big clue that this has only been happening the last eight years. This leads me to be skeptical that the open trash containers and fish refuse thrown by fisherman is the cause…trash has been around for a few decades and the fishermen have most likely always discarded the unwanted fish parts…so why now?
I found this. Interesting–but not really surprising because mercury is a known neurotoxin, so it is conceivable that it would affect that part of the brain that sexual desire is located. It is fairly well known among the mercury group that desire is affected. I don’t think this subject has been broached, probably because of the sensitivity of the subject.
Here’s a paper on mercury’s devastating effects on humans, fish, birds, et al. If you look on page 7, there is a table with an astonishing number of over 4 billion tons of mercury in the ocean water.
From the paper:
There is a strong relation between the food of birds from Minamata and the Hg content in feathers; the content is highest in fish-eating seabirds and lowest in herbivorous waterfowl (Doi et al. 1984; Table 4). This same relation held in birds collected from China and Korea, although concentrations were significantly lower (Doi et al. 1984). There are close correlations between Hg contents of zooplankton and suspended particulate matter, and of sediments and fish muscle, suggesting a pathway from sediment to fish by way of suspended matter and zooplankton. The conversion from inorganic Hg to methylmercury is believed to have occurred primarily in zooplankton (Nishimura and Kumagai 1983).
An elevated concentration of mercury (i.e., >1.0 mg/kg fresh weight), usually as methylmercury, in any biological sample is often associated with proximity to human use of mercury. The elimination of Hg point-source discharges has usually been successful in improving environmental quality. However, elevated levels of mercury in biota may persist in contaminated areas long after the source of pollution has been discontinued (Rada et al. 1986). For example, Hg remains elevated today in resident biota of Lahontan Reservoir, Nevada, which received about 7,500 tons of mercury as a result of gold and silver mining operations during the period 1865 to 1895 (Cooper 1983). It is noteworthy that some groups of organisms with consistently elevated Hg residues may have acquired these concentrations as a result of natural processes, rather than from anthropogenic activities. These groups include older specimens of long-lived predatory fishes, marine mammals (especially pinnipeds), and organisms living near natural Hg-ore-cinnabar deposits.
If you look down a bit, they list the Bald Eagle egg as increasing its mercury contamination from .35 in 1974 to .84 in 1979–doubled.
Further down, it lists a cat that ate fish below a chloralkali plant–look at the fur: 121 mg mercury /kg
The harbor seal in California: 269 mg/kg
The striped dolphin in Japan: 205 mg (in the liver)
The sea lion in California: from 73.0 to 1,026 mg/kg
The paper goes on to summarize that mercury in birds was highest by those that ate fish and other birds.
More from the paper:
The most probable source of recent elevated Hg residues in feathers of the Finnish sparrowhawk (Accipiter nisus) was from consumption of avian granivores that had become contaminated as a result of eating seeds treated withorganomercury compounds; in 1981, 5.6 tons of methoxyethylmercury compounds were used in Finnish agriculture for protection of seeds against fungi (Solonen and Lodenius 1984).
Another reason to push for sustainable farming practices…birds being contaminated by mercury application (as a fungicide) by farmers.
This is an understatement:
Mercury is a known mutagen, teratogen, and carcinogen. At comparatively low concentrations in birds and mammals, it adversely affects reproduction, growth and development, behavior, blood and serum chemistry, motor coordination, vision, hearing, histology, and metabolism. It has a high potential for bioaccumulation and biomagnification, and is slow to depurate.
Mutagens change your DNA. Teratogen is a fancy word for birth defects. And of course, carcinogen is cancer causing. Note that this states low concentrations affect behavior–hence my concern about the seagulls attacking the whale is not normal behavior and that’s why I suspect mercury (or other toxins).
This also applies to we mammals by the way:
Mercury has no known physiological function (EPA 1985). In humans and other mammals, it causes teratogenic, mutagenic, and carcinogenic effects; the fetus is the most sensitive life stage (NAS 1978; Chang 1979; Khera 1979; EPA 1980, 1985; Elhassani 1983; Greener and Kochen 1983; Clarkson et al. 1984). Methylmercury irreversibly destroys the neurons of the central nervous system. Frequently, a substantial latent period intervenes between the cessation of exposure to Hg and the onset of signs and symptoms; this interval is usually measured in weeks or months, but sometimes in years (Clarkson et al. 1984). At high sublethal doses in man, mercury causes cerebral palsy, gross motor and mental impairment, speech disturbances, blindness, deafness, microcephaly, intestinal disturbances, tremors, and tissue pathology (Chang 1979; EPA 1980, 1985; Elhassani 1983; Clarkson et al. 1984). Pathological and other effects of Hg may vary from organ to organ, depending on factors such as the effective toxic dose in the organ, the compound involved and its metabolism within the organ, the duration of exposure, and the other contaminants to which the animal is concurrently exposed (Chang 1979). Many compounds–especially salts of selenium–protect humans and other animals against mercury toxicity, although their mode of action is not clear (NAS 1978; Chang 1979; EPA 1980, 1985; Eisler 1985).