STEM Logo

Dive Dry with Dr. Bill

#583: Scorpionfish "Sting"

Diving at night offers a distinct advantage that those who descend in daylight lack. No, I'm not suggesting that not being able to see far is a benefit... it often increases the fear of the unknown in some people. You know, that irrational fear that Jaws will chomp you in half! Diving with my video lights actually makes at least two potentially harmful fish more evident and easier to avoid!

These fish will not swallow you whole (or even bite your pinkie off if it gets too close). The danger they pose to divers has more to do with the desire of any species to defend its life against attack by predators! I'm referring to the sharp spines of the scorpionfish with their toxic venom. No, they don't have eight legs, but they do share a powerful "sting." Although some species in this family found in other oceans can actually kill, the poison in these fish may cause pain, vomiting, migraines and other agony but is not lethal to us. However, only a true masochist would intentionally make contact with them. If you aren't one, hot water may lesson the pain of a sting since it denatures the protein-based toxin..

It is hard to describe the common California scorpionfish (Scorpaena guttata) because it is so variable in color. They may be brown, red, orange, lavender and cream with blotches, saddles and other patterns. The things they do seem to have in common are thick bodies, dark brown spots (although these may be absent), sharp fin spines and fleshy lobes above the eyes. They may reach up to 19 inches in length and 4.4 pounds.

California scorpionfish are found... where else but California (both Alto and Baja). The northern limit is Santa Cruz and they extend down Baja into the Gulf of California (or Sea of Cortez) at depths from the immediate subtidal to 600 feet although they are most common from 33 to about 280 ft. They are most abundant from Point Conception to southern Baja. Habitat preferences generally include rocky or mixed rock and soft bottom substrates.

Dr. Milton Love states that although these fish prefer dwelling on the bottom during day, they may be found in midwater or even near the surface at night. I must admit that in my dives here, the only time I've seen them enter the water column was when they were fleeing my camera. However, Milton has much broader experience with these things so I'll take his word on it.

The California scorpionfish has a varied diet including small crustaceans like crabs, shrimp and skeleton shrimp; squid; octopus and small fish. They are reported to be ambush predators, lying in wait on the reef for a victim to come too close. Dr. Love suggests there are few species that prey on them in turn. So why do they need camouflage and poisonous spines for protection? Apparently it is an effective deterrent! Of course the camouflage allows them to hide and not attract the attention of their prey... until it is too late! They were targeted by commercial fishers around Catalina Island back in the late 1800s and sold in Los Angeles markets.

California scorpionfish may be sexually mature as small as six inches in length. They spawn mainly between May and August. Dr. Love states that large spawning aggregations may be found at this time. The larvae are planktonic, dispersing far from their parents. Like humans, females generally live longer than males... 21 as opposed to 15 years.

I was surprised to find barely a mention in Dr. Love's Certainly More Than You Want to Know About the Fishes of the Pacific Coast about the rainbow scorpionfish (Scorpaenodes xyris) since the book is an otherwise fantastic source of information. This species is found from Anacapa Island to our north into the Gulf of California, but Dr. Love states that they are "occasional" around our island. I see them on every night dive I make and many day dives as well if I poke through the nooks and crannies in the reef.

The body color on these fish is a bright red, making them very obvious in my bright video lights at night. As you may remember, red is the wavelength of light that is filtered out first in the water column. For example, blood looks black at depth and in deep water you will often find red algae which reflect red light but capture the other wavelengths for photosynthesis that penetrate into deeper water. Thus under conditions of darkness these fish are essentially invisible, using color for camouflage. I've repeatedly encountered a pair of them at one stop during my night dives, a small cavelet. Don't know if they just like some company or if they have something more libidinous and licentious in mind. All I know is they weren't telling. Good for them... modesty is a too often forgotten virtue these days.

© 2014 Dr. Bill Bushing. Watch the "Dive Dry with Dr. Bill" underwater videos on Catalina Cable TV channel 29, 10:00 AM weekdays and on Charter Communications Cable channel 33 at 7:30 PM on Tuesdays in the Riverside/Norco area. You can also watch these episodes in iPod format on YouTube through my channel there (drbillbushing). Please help me climb out of self-imposed poverty... buy my DVD's (see this link). Yes, take Dr. Bill home with you... we'll both be glad you did!

To return to the list of ALL of Dr. Bill's "Dive Dry" newspaper columns, click here.


California scorpionfish (top) and rainbow scorpionfish (bottom).

This document maintained by Dr. Bill Bushing.
Material and images © 2014 Star Thrower Educational Multimedia