To Bite, or Not to Bite

That’s an age old dilemma.  I put surfperch to the test last year with a preference experiment.  I presented colored lures to surfperch in the wild.  If surfperch bite each color equally then there is no preference.  If there is a preference, color matters and we get some insights about the visual ecology of surfperch and why, perhaps, they have found so many ways to add color to the otherwise drab surf zone.  I illustrated a few examples recently in Fins on Fire.

You can decide for yourself whether the lure colors I chose for my experiment are relevant.

Black – a distinctive color spot on walleye surfperch pelvic and caudal fins, and sometimes on silver surfperch anal fins

Brown – a composite color possibly resembling the camouflage coloration we frequently see in surfperch prey

Red – namesake of the redtail surfperch

Orange – prevalent color of Emerita analoga eggs and a distinctive color spot on the anal fin of some silver surfperch

In a pilot experiment, described last year in Choices, Choices…Everywhere, I showed that silver surfperch, Hyperprosopon ellipticum, disproportionally bit p-seed (brown with black flecks) and orange lures, suggesting that color matters to silvers.  Here are those results.


To test this result I repeated the experiment, with refinements, and four of the five colors I used in the pilot – black, brown (a simplified version of p-seed), orange and red.  I dropped yellow from the rotation and I kept track of sexes. Here’s what I found out about the preferences of 27 female and 36 male silvers.


The sexes made remarkably similar choices.  Both sexes prefer to bite an orange lure and the signal is stronger than in the pilot experiment.  The preference illustrated here may be a little more complicated that just a preference for orange (reflectivity between 595 and 635 nm) because what fish see is complicated.  Here’s just one example: some objects not only reflect light, they also emit light – they fluoresce.  In the pilot experiment, spectrophotometry suggested that that orange and yellow lures had fluorescent properties while red, p-seed and black lures did not.  Fluorescence may be part of the picture but consider this – p-seed performed well without fluorescence and yellow performed poorly with fluorescence, so if it plays a role, fluorescence itself is not the whole story.  Whatever the reason, silver surfperch have a preference for my orange lures.

Exploring color preferences in silvers is a natural because of the combinations of color we see on the anal fin.  Redtails, Amphistichus rhodoterus, don’t show off interesting color spots but they do have red fins, especially caudal fins and thus they offer an opportunity for comparison with silvers.  There is another thing. They are, after all, the King of the Surf; it wouldn’t be fitting to talk about lure color preferences in the surf zone without mentioning redtails.  The results for 43 female and 75 male redtail surfperch are shown below.


Here it looks like the sexes behave differently.  Among males, bites on orange and red are are overrepresented compared to the no preference expectation.  Those males really like a red lure.  Females, on the other hand, bite most on orange, just like silvers.  Black is underrepresented compared to the no preference expectation in both sexes, just as we saw in silvers.

My refined experiment elicited 181 adult surfperch bites.  That’s a lot of bites…I guess the solution is to bite.

Acknowledgements. – Several people helped me plan this experiment and encouraged along the way.  We’re still thinking about the results.  I especially want to thank Mike Westphal and Helen Rodd.