It is known that in the early 1970’s there use to be very large catches of river herrings within the fishing industry …show more content…
Ogburn focused on four major objectives in his research that investigated the migratory conservation of River Herrings within the Chesapeake Bay. These objectives are; firstly, to conduct tributary scale monitoring of population dynamics and environmental drivers of spawning run. Secondly, to conduct watershed scale monitoring of presence or absence in spawning streams. Thirdly, to develop bay-wide habitat using models that will inform conversation and restoration planning. Lastly, to use track individual-scale and spawning habitat as it responses to dam removal. Additionally, another study site where Dr. Ogburn and his team observed and study river herrings is the Choptank River in …show more content…
This apparatus aids by sending sound waves, which bounces back when the fish swim by as it counts and records how many fish are near or swim closely by. This data is recorded every ten minutes of every hour and high-resolution images are obtained. In addition, electrofishing of species ID and CPUE was used to count the fish ranging from twenty-five to thirty centimeters which was the ideal size for this investigation. These methods were used to analyze four biological sampling, which observed: the type of species, the length and sex, otoliths for aging, scales for spawning mark counts, and fin clip for genetics. This allowed to obtained accurate numbers of run counts of fish and also observed how many of those were river herrings alewife or blueback herring.
As a result, the demography of this investigation showed that spawning occurs between the ages of 3 or 4 years in river herrings but they can start spawning as early as age two or as late as age 5. Moreover, a question that arose while doing the run counts in river herrings was is there a true diel cycle? Results obtained for this was that the fish that were upstream were commonly seen in the afternoon or in the evening whereas, the fish that were downstream from the river were commonly seen at the hours of 6:00 AM or 6:00PM. Thus, the fish were not constant through