October 6, 2017 — ARLINGTON, Va. — The following was released by the Atlantic States Marine Fisheries Commission:
In May, the Atlantic States Marine Fisheries Commission’s Atlantic Herring Section approved the continued use of the GSI30-based forecast system to predict when the population will be spawning and when spawning closures should be set based on the development of herring gonads (reproductive organs) in Area 1A (inshore Gulf of Maine). GSI stands for gonadosomatic index and in its simplest terms assesses the onset of spawning based on the ratio of the weight of a female herring’s ovaries to its body weight. This new system, which was successfully piloted in 2016, uses the observed rate of increase in GSI to predict when spawning will occur and when the fishery will be closed. This replaces an earlier system that simply closed the fishery when the observed GSI was above a threshold value.
Stakeholders can see the spawning forecast model in real time here: https://www.massmarinefisheries.net/herring/.
Atlantic herring spawn in the late summer or early fall of each year. The timing of this event can vary by several weeks, which necessitates sampling the population each year to determine when the spawning closure should occur. Once three samples have been collected that show a positive progression in gonadal development, a forecasted closure date can be determined by projecting forward when the population is likely to cross the spawning threshold. This forecasted closure date is continuously updated as new samples are acquired, and the closure is finally set within 5 days of the forecast date.
If not enough samples can be collected to forecast a closure date, a default closure date will go into effect. This date varies slightly by region:
- Eastern Maine: August 28th
- Western Maine: October 4th
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Massachusetts-New Hampshire: October 4th
Whether initiated by the forecast model or a default date, the spawning closure lasts four weeks. If more than 25% of sampled fish are still in spawning condition when the fishery is reopened, the fishery will reclose for another two weeks. For more information, please contact Toni Kerns, ISFMP Director, at tkerns@asmfc.org or 703.842.0740.
Read the release at the Atlantic States Marine Fisheries Commission