Photo of the Week: January 30, 2012

Hi Gang!

This week’s POTW is a second image from my dive on January 2, 2012 on the Eureka oil platform off Long Beach, California. The shot is a picture of a male California sheephead, Semicossyphus pulcher, swimming through part of the rig’s invertebrate encrusted support structure.

The California sheephead is an iconic fish species in the waters of southern and central California waters. A treat for divers and a highly sought after food source by fishermen, California sheephead are generally considered to live in association with the seafloor in relatively shallow, inshore waters of kelp forests and other areas where the substrate is rocky. The oil rigs have become artificial reefs and it is not uncommon for divers to encounter California sheephead on their oil rig dives where all marine life is protected by the no-take staus of the water surrounding the rigs.

California sheephead are members of the wrasse family. Similar to other wrasses, California sheephead undergo three life phases, a juvenile, initial and terminal phase. All California sheephead are hatched as females (juvenile phases) and remain females through both their juvenile and initial phases. Terminal phase California sheephead undergo a sex change and are transformed into males so that breeding females have access to a potential mate.

If not enough males are present in a given area, dominant females will soon develop into males. When California sheephead become males, the fish develop a large bump on their forehead and the previously pink-to-red head and rear of the body turn black. California sheephead have large protruding teeth that are used for crushing and prying open the hard shells of mollusks, crustaceans and echinoderms, including sea urchins that they prey upon.

To clear up a point of potential confusion I want to make it clear that the words sheephead and sheepshead are used to refer to several species of fishes in waters around the world. Not all of those species that are known as some type of sheephead or sheepshead are types of wrasses. The fish in this week’s POTW image is specifically known as the California sheephead.

For several reasons including pollution and fishing pressure, California sheephead populations have seriously declined in recent years. However, the species appears to be on the rebound. In any case, it was a nice feeling not only to see this male, but to see a number of males around the Eureka oil platform.

If you would like any additional information regarding the oil rigs off California coast or the invertebrates in this photograph that have encrusted the structure of the oil rig, check out last week’s POTW. I shared two images from my recent day at the Eureka rig in consecutive POTWs, and I elaborated on the rigs and some of the invertebrates in last week’s piece.

I created this week’s POTW with my Nikon 17-to-55 mm zoom lens set at a focal length of 35 mm. This lens is a great choice for creatures that are the size of a typical lobster to a sea lion. That said, the lens is used behind a dome port in my Subal housing, and when using the set up around a reef I have to be careful not to bash into the substrate, an act that can damage the reef scratch my dome port.

I really enjoy using my 17-to-55 mm lens. The way I often use it is to get as close to my subject as I can so that I can shoot through as little water as possible. Doing that means I shoot through as few suspended particles in the water as possible, and I can get the most vivid colors with my strobes. So, I get close and then ride the zoom control to alter the lens’ angle-of-view to compose my frame.

I hope you enjoy this week’s POTW!

See you next week,

Marty