Scientists think that Maine’s striped bass population is made up of fish that are spawned locally and fish that migrate from more southerly regions, but it is challenging to understand the relative contribution of each group. After all, if you catch a striper in the ocean, how can you tell where it came from?
This gap in our understanding has hampered efforts to determine the cause of a recent downturn in the catch of stripers and to identify the changes in management that might reverse the trend.
Our researchers believe the fish may have telltale characteristics that could be used to decipher their origins and life histories, but there is little available data on Maine’s stripers and no commercial fishery to help collect it.
To address this critical lack of data, GMRI has partnered with the Maine chapter of the Coastal Conservation Association to engage anglers as citizen scientists. The Snap-A-Striper program allows them to share valuable information about the fish they catch and to help us build the knowledge needed to better manage this resource.
When anglers catch a striped bass, they fill out a data card and photograph the fish next to it. Using image analysis software, our science team can obtain accurate body measurement data and look for distinct body shapes that might allow them to tell fish from individual populations apart.
Anglers can also bring the head of any legal fish they keep to one of several drop-off locations so our science team can perform chemical analyses on the fish’s ear bones. The estuaries where stripers are spawned impart distinct chemical characteristics to the ear bones. When this data is combined with the body shape analysis, it will allow us to determine the origin of individual fish.
Snap-A-Striper had its first field season in the summer of 2013. Anglers along the coast contributed about 140 images and 13 striper heads. A promising initial analysis of this data revealed a body shape difference between stripers caught in the Kennebec River and in Casco Bay that may enable us to differentiate fish based on photographs.
Will these initial findings hold up across more locations and times? How will this compare with what we learn from the fish’s ear bone chemistry? We’ll be working closely with Maine’s anglers again this summer to try and find out.