Two Bar Jacks
|Copyright: Alfredo Wang (alfhwa)
|Date Taken: 2007-10-25|
|Camera: Olympus Stylus 770SW|
|Exposure: f/3.5, 1/400 seconds|
|More Photo Info: [view]|
|Photo Version: Original Version, Workshop|
|Date Submitted: 2007-11-07 7:23|
|[Note Guidelines] Photographer's Note|
|These 2 Bar Jacks are taking their time while feeding on these small fishes. Anywhere you look, there are these small fishes swimming around. They probably thought I was the predator, but you feel like a prey when swimming next to them.|
Order - Perciformes
Family - Carangidae
Genus - Caranx
Species - ruber
The bar jack is found from New Jersey through Bermuda, in most of the Gulf of Mexico, the Caribbean, and the West Indies. It is uncommon in the northern Gulf of Mexico. There has been an unconfirmed capture of a bar jack in Rio de Janeiro, Brazil. It is the most common Caranx in the West Indies and Bahamas.
The bar jack usually lives in clear, shallow waters over coral reefs. It is typically found in schools varying in size from a few fish to many. Occasionally the bar jack is seen swimming alone. Juveniles may be observed under patches of Sargassum mats. Schools of larger fish also occur under large Sargassum on occasion.
The bar jack grows to over 19.7 inches (50 cm) in total length, although it is more common at lengths to 15. 7 inches (40 cm). It reaches weights of 15-18 pounds (6.8 - 8.2 kg).
The bar jack has somewhat of a dual feeding mode. Although its diet mainly consists of fish, shrimp, and other invertebrates, the bar jack can also be a bottom feeder. Bar jacks are usually bottom feeders in their first or second year of growth. Juveniles sometimes follow a bottom feeder such as a stingray, eating whatever is stirred up. This, however, is not the preferred feeding mechanism of the bar jack. A bar jack feeding in this way ends up with a stomach mostly filled with shells, sand, and pieces of coral. Young bar jacks feed primarily on zooplankton close to the surface of the water. These fish take in food every 5-7 seconds. The bar jack is a sight hunter, eating only what it can see. For this reason, this jack is inactive during the nighttime hours.
Predators of the bar jack include the greater amberjack (Seriola dumerili), dolphin (Coryphaena hippurus), king mackerel (Scomberomorus cavalla), cero mackerel (Scomberomorus regalis), and yellowfin grouper (Mycteroperca venenosa).
Source: Florida Museum of Natural History
LordPotty, gracious, jessbalderas has marked this note useful
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This is a really good shot of these predatory fish and their prey.
Beautiful capture,very nicely presented.
I thought it might have more impact with a little more contrast and sharpening,so I've put an altered image in the workshop for you to compare.
Hope you don't mind.
Sometimes people miss good photos if they can't tell straight away from the thumbnail what it is.Its a bit unfortunate,but bright objects like butterflies and caterpillars seem to get noticed the most.
This is a great shot though,so I hope it gets a few bites ;)
Great note too by the way.
Your 770SW is doing a great job for you here in this shot!
Perfect exposure and focus with good clarity and so much details
thanks for the most useful notes and information provided!
thanks for sharing
all the best