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Tuesday, September 28, 2010

American Shad Migration in the Delaware River: 2010

The biologist's at the Pennsylvania Fish & Boat Commission released their annual American Shad Migration Report.  Findings show the shad run was the fourth highest since 1997.  Good news for a fish that has seen a decreasing trend taking place throughout its range from Florida to Nova Scotia. The decline that has been so bad that the fishery was completely closed this year in New York's Hudson River.

Interesting is the size of females shad have shrunk to 2.4 – 4.9 pounds or 17.1 – 22.2 inches.  This has the biologists scratching their heads. Possibilities include a combination of gear avoidance, more younger females from the 2007 year class as three year olds, natural mortality of larger females from the spawning population (i.e., the loss of the 2005 female year class as five-year-olds or they simply did not return to spawn this year), poor young of year survival from the record June 2006 flood, slow growth in the ocean, etc. In contrast, the size of males from the 2010 run were about the same as in past years.

Hopefully the shad run will continue to increase and we can look forward to seeing the abundant runs of the past.