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Something's Fishy with Chinook Salmon

Samples in 1999 from fall chinook salmon in the Columbia River's Hanford Reach show that four-fifths of the females spawning there apparently began life as males, according to ENN for CNN!

The genetically altered females, instead of carrying the normal two X chromosomes, appear to carry one X and one Y chromosome, the normal genetic signature of the male. The altered females of the Hanford Reach produced eggs, spawned and then died as is normal in the Pacific salmon's life cycle.

DNA from small pieces of fin showed the genetic markers that indicate their male genotype. The mating of a genetically altered female and a normal male could then produce males with two Y chromosomes, and such males could then only produce male offspring, thus imbalancing the sex ratio of spawners!

The finding could provide an important clue in sorting through the complex reasons for the general decline of Northwest salmon runs, although the Hanford's wild fall chinook run is among the healthiest. The researchers ruled out radiation as a possible cause of the apparent sex reversal but suggested environmental contaminants that mimic hormones or water temperature changes could be the culprits.

Strawberry Fields May Not Be Forever

The phasing out of one of the nation's most widely used pesticides will begin taking a bite out of California's strawberry business this year, experts say, raising costs, lowering yields and giving Mexican imports a competitive advantage.

Researchers at UC Davis estimate that California's nearly $850-million strawberry industry, which produces most of the nation's crop, will lose 20% of its production with the ban on the fumigant methyl bromide.

Methyl bromide is injected into the soil before planting to sterilize it and kill pests. The soil is then covered with plastic tarps to slow the leakage of the gas into the atmosphere. But 80% to 95% of the methyl bromide injected into the soil for row crops eventually enters the atmosphere, the EPA says, whether or not the fields are covered.

Although many environmental and consumer groups worry about methyl bromide residue on food, the biggest risk, experts say, is to workers fumigating the fields.

Exposure to the chemical can result in central nervous system and respiratory failure, as well as severe reactions in the eyes, lungs and skin. It also has been tied to birth defects, and high concentrations have resulted in a number of deaths.

The chemical is used on more than 100 crops, but California strawberry growers use it the most, applying about 6.7 tons of the fumigant annually to their fields. In fact, strawberries are the most heavily treated of all food crops, largely because of the large amounts of methyl bromide used, according to a report by the San Francisco-based Pesticide Action Network.

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Last modified: April 28, 2001