News DMF Conducting Studies on Striped Bass Release Mortality

  • Division of Marine Fisheries

DMF implemented regulations last year requiring the use of circle hooks while recreationally fishing with live or dead bait for striped bass in place of J hooks which been shown in studies to “deep hook” more often than circle hooks. The rest of the East Coast states joined us this spring in also requiring circle hooks to comply with the rules set out in Addendum VI to Amendment 6 to the Atlantic Striped Bass Interstate Fishery Management Plan.  Also part of Addendum VI was the requirement to reduce removals by 18% through new bag and/or size limits.  Following Addendum VI, DMF implemented a recreational limit of 1 striped bass per day, within the slot of 28” to less than 35” total length.  These strict new rules are intended to reduce mortality so that the striped bass stocks can begin rebuilding.

The circle hook regulations were put in place to try to reduce mortality in the released fish. Studies have shown that about 9% of striped bass die after they are released from hooking and handling damage. In Massachusetts, we release millions of striped bass each year. When we apply the 9% mortality to this number, we end up with 3-4 times more mortality from released fish than from fish we take home to eat! On a coastwide basis, almost half of all the mortality in striped bass is from caught and released fish. As you can see, reducing the mortality of released striped bass is critical to the sustainability of the striped bass population and the use of circle hooks is the first step to accomplish this reduction.

DMF is currently conducting studies to better characterize release mortality in striped bass. The studies are using acoustic tags that have built in accelerometers (the same technology that makes your smart phone screen flip when you turn the phone sideways). A vast array of acoustic receivers all along the Northeast U.S. can detect the acoustic signal from a tagged bass and record not only it’s location but also deduce if the fish is dead or alive by detecting tailbeats recorded by the accelerometer. Through these studies we hope to re-evaluate and validate (or change) the currently used 9% release mortality and also determine the benefit of circle hooks vs. J hooks and other features of hooks such as gap size.  Future studies will document the effect of handling/fight time, water temperature, and treble hooks on artificial lures. The goal of these studies is to supply fishery managers with good data so that they can implement rules that will maintain a robust and sustainable striped bass population.

By Michael Armstrong, PhD, Assistant Director

Division of Marine Fisheries 

The Division of Marine Fisheries manages the state’s commercial and recreational saltwater fisheries and oversees other services that support the marine environment and fishing communities.

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