Jackson Estuarine Laboratory


Ecological studies of economic red algae. III. Growth and reproduction of natural and harvested populations of Gigartina stellata (Stackhouse) batters in New Hampshire


The growth in situ of populations of Gigartina stellata (Stackhouse) Batters has been recorded at three New Hampshire locations and correlated with seasonal and spatial variations of surface salinity, temperature, and nutrients. Annual growth began between February and May, depending upon the location and its hydrographic regime. Gigartina populations reached maximum biomass and size in August and September, and a general decrease in both occurred during the reproductive period from October to February. The period of fastest growth coincided with increasing summer temperatures, while maximum carpospore release occurred during the period of decreasing (coldest) temperatures. The largest plants and maximum biomass of Gigartina were found on the open coast (at a semi-exposed site) while smaller plants and reduced biomass were evident within the Great Bay Estuary System. Salinity is a dominant factor influencing both the local distribution and growth of the plant. Gigartina is primarily restricted to the littoral zone, and its maximum length and biomass occur between +0.45 and +1.0 m above M.L.W.

Experimental plots were established to determine the effects of differential levels and seasons of harvesting on G. stellata. Summer (August) harvesting allowed control levels of biomass and population structure to be reached after one year, while winter (December) harvests attained control levels after 19 months. Denuded and sterilized quadrats required more than three years to re-establish themselves. Harvesting in December gave control levels of reproduction in the careful and moderately harvested plots after 9 and 12 months respectively. An August harvest deprived all the plots of reproductive potential until the following reproductive season.

Publication Date


Journal Title

Journal of Experimental Marine Biology and Ecology

Digital Object Identifier (DOI)

Document Type