Defend Against Predators or Run? Evolutionary Tradeoffs in Butterflyfish

How does a fish avoid being eaten by a bigger fish? Evolution could build up defenses such as spines or armor, or favor avoidance strategies such as quick reactions, swimming away and hiding. The rules of evolution are tough, so you cannot really have both, the argument goes.

But this hypothesis has been difficult to test in practice. Now Jennifer Hodge, a postdoctoral researcher working with Professor Peter Wainwright and colleagues in the UC Davis Department of Evolution and Ecology, College of Biological Sciences, has carried out a survey of hundreds of specimens of butterflyfish, carefully measuring their physical traits and defenses compared to feeding style.

Elastic Slingshot Powers Snipefish Feeding

The snipefish, an ocean-dwelling relative of the seahorse, has a very long, skinny snout ending in a tiny mouth. A recent study by UC Davis graduate student Sarah Longo shows that snipefish feed with an elastic-boosted head flick at almost unprecedented speed.

“At as little as two milliseconds, it’s among the fastest feeding events ever recorded for fish,” said Longo, now a postdoctoral researcher at Duke University.

Snipefish, seahorses and pipefish all have long, skinny snouts and use “pivot feeding” to capture food, Longo said, meaning that they pivot their head rapidly to bring their mouth up close to the prey and suck it in.

Thin snowpack is bad news, especially for salmon

State water officials announced yesterday that the Sierra snowpack is 61 percent of normal for this time of year, making for the third dry year in a row and raising the possibility of water rationing in California. (DWR press release here; a video is also available).

“We may be at the start of the worst California drought in modern history.  It’s imperative for Californians to conserve water immediately at home and in their businesses,” said Lester Snow, director of the state Department of Water Resources, in the press release.

Polluted Bay, deformed fish

A new study from UC Davis researchers shows that baby striped bass hatched from female fish collected from San Franciso Bay contain pollutants including flame retardants, industrial chemicals and pesticides passed on from their mothers. The hatchlings had damaged brains and livers, and grew more slowly than fish raised in clean water in a hatchery.

“This is one of the first studies examining the effects of real-world contaminant mixtures on growth and development in wildlife,” said study lead author David Ostrach, a research scientist at the UC Davis Center for Watershed Sciences. He said the findings have implications far beyond fish, because the estuary is the water source for two-thirds of the people and most of the farms in California.