There have been reports for several days of large numbers of dead fish washing onto some of our road-end beaches, particularly those on E. Lee, E. Highland and E. Prospect Streets. The cause is not the mystery it first seemed. The fish have been identified as three-spine sticklebacks, and they have died of what—for them at least—is a natural cause: rough sex.
According to King County’s Water & Land Resources Division, the lot of the male stickleback during breeding season is an unpleasant one. First there’s the swimming around furiously to attract a mate, then there’s the mating itself, and finally there’s the nest building and caring for the young. What the female is doing all this time is not specified. But the males are pretty worn out from their exertions at the end, and many of them go on to their reward. In this case, the reward is more on the side of the eagles, crows and rats who are making tasty meals of the stickleback carcasses. The beaches are picked fairly clean, but some of the remains are now littering the gardens and pathways around the beaches.
Sidebar: As I was researching this story today I discovered coincidentally that the beach at Madison Park is experiencing a big spike in fecal coliform levels, rising from a level of 16 on June 9 to 470 on June 15, by far the highest level of any beach on Lake Washington as measured by the County. Fecal coliforms are a group of intestinal bacteria that are routinely used as an indicator of sewage pollution in water.
Madison Park’s recent reading of 470 is still within the acceptable level, though levels above 200 are considered of Moderate Concern, according to the County. To reach High Concern, the level would need to reach 1000, at which point the beach would probably be closed to swimming.
I talked to Dean Wilson, who is a senior water quality project manager with King County, and he reports that an individual reading at a particular beach “could represent a sampling artifact such as geese being in the area around the time the sample was taken.” He said that overall, Madison Park currently has a geometric mean for the last five samplings of 50, which shows high-quality water. If next week’s sampling shows an elevated level of fecal coliforms there would be a need to monitor the situation more closely, he said. If the reading is high next week, I will report it.