MarineFisheries Article of the Month

MarineFisheries has a monthly brown bag journal club. Next week we’ll be discussing the following paper:

Costello, C.T. and W.J. Kenworthy. Twelve-Year Mapping and Change Analysis of Eelgrass (Zostera marina) Areal Abundance in Massachusetts (USA) Identifies Statewide Declines. 2011. Estuaries and Coasts. 34(2) 232-242. (http://www.springerlink.com/content/b5414gnm3g26713u/fulltext.pdf)

Key Points:

The study involved mapping eelgrass in coastal areas and embayments in Massachusetts’ waters 3 times over a 12 year period, 1994-96 (t1); 2000-2002(t2); 2006 & 2007(t3).

Overall seagrass in Massachusetts’ coastal waters is declining by a rate of -2.21 to -3.51%, which is consistent with the rest of the world’s eelgrass population declines ( -3.7 % ). However, the rate of decrease differed between the two change analysis montoring events, with a lower rate of decline in the second monitoring event.

Between T2 and T3, 11 embayments showed an increase. The 3 largest were Boston, Salem and Gloucester Harbors. One reason behind the success of eelgrass recovery in these harbors is the improvement to water quality due to changes in waste water management. In Boston Harbor, the wastewater treatment plant was upgraded to secondary treatment and the outfall was relocated 15k further offshore. An outfall in Gloucester harbor was relocated as well.

Eelgrass has declined partly due to anthropogenic effects and it is our responsibility to make improvements – MassDEP is working with individual towns to develop TMDL thresholds, to control how much Nitrogen can enter a system each day.