Tagged Redfish Detected 60 miles Offshore

From 2007-2010, redfish were tagged in conjunction with the Water LIFE Kids Cup Redfish Tournament. During those years, redfish caught and weighed in (at Fishermen’s Village in Punta Gorda) by anglers aged 10-16 were fitted with tags and released. All of the fish (over 200) received an externally anchored dart tag and some fish (80) received a surgically implanted acoustic tag. These later tags were VEMCO tags and tracked using their underwater tracking equipment. The

In February 2012, we learned that a tagged redfish showed up at the Stoney Point Reef located 60 miles offshore of Ft. Myers in 135 foot of water! Based on the data logs, the redfish first appeared in November 2011. It was recorded again in December 2011 and then several times in February 2012.acoustic tags work by transmitting a unique signal into the water which is decoded and recorded by the tracking equipment. The tracking equipment is periodically downloaded to a computer to see which fish passed close enough to the receiver to be recorded and on what date and time.

The fish that showed up at the Stoney Point Reef was originally caught during the May 15th, 2010 Kids Cup tournament. It weighed in at 4.80 pounds and measured 24.63 inches total length. Today based on average growth rates that fish is well over 30 inches, indicating it has reached the age when redfish leave the estuary to spawn.

Redfish spawn inshore close to tidal inlets through which the young are transported into estuaries. Spawning occurs in late summer and fall. Redfish have an elaborate courtship ritual. Males, sometimes many, follow females for hours at a time, drumming loudly and butting them. Male color intensifies during courtship and climaxes just after dark when eggs and sperm are released. Females may shed a million eggs at a time.

Growth rate for redfish varies throughout their lifecycle. During the first year they grow at a rate of one inch or more a month, after which time growth rate slows to ½ – ¾ ” per month. Redfish continue to increase length throughout their lives. However, after 3-feet-long they add little length and lots of girth as they age. Redfish mature around 2 to 4 years in age and live for 25 to 35 years.

Adult redfish are known to form large aggregations offshore on wrecks. Many studies have evaluated redfish aggregates on wrecks at one hundred foot or more so although this finding was very surprising it was certainly a realistic observation. Perhaps it was most shocking because it was only by chance that a researcher had acoustic equipment offshore to make this detection.

Of course once we get past the “how cool is that” phase we have to ask all of the “what if” questions and the big one here was could this redfish have been eaten? If so, would these detections be from the predator? The truth is predator/prey transfer of tags has not been well evaluated in fishes, so yes it is a possibility but in this case not likely. The reason being is there is nothing along the digestive track for a foreign object (in this case the tag) to adhere to. So while it may sit in the gut for a short period of time, at some point it will be expelled. Back to this fish, it was recorded over a four month period which is far longer than a tag would likely remain in the gut of a predator fish.

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Posted: April 13, 2012


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