Observations on Flounders Pleuronectes Flesus L. Marked in the Esturaries of the Tamar and Lynher

Abstract

1039 flounders were marked with numbered vulcanite disks in the estuaries of the Tamar and Lynher.148 flounders were recaptured and of these seven fish were recovered a second time after one recovery and release, and one fish was recaptured on three occasions after two previous recoveries and releases.Only two fish were recovered at a distance from Plymouth. Both had moved eastward, up the English Channel.There was little or no growth in the winter months.Individual growth rates were found to vary greatly.The flounders living in the last reach of the Tamar near Saltash tended to remain in one limited area during the winter months, save for a drift down-stream of some of the larger fish. In the spring there was an upstream movement of the smaller, immature fish.Flounders which had gone down to the sea to spawn might return to the river in which they were marked, or to the other river of the two which join to form the Hamoaze, or they might move right away from the area where they were marked.