Spatial distribution and seasonal variation in Undaria pinnatifida ...

maximum of 52% of the plants measured had sporophylls at any one time. The numbers of plants with sporophylls presentat both sites collapsed from early January. No plants with sporophylls were recorded at either site in March 2012.Sporophyll volume peaked between early November and mid-December at both Westhaven Marina and Coromandel.Figure 14: Reproductive status of Undaria populations. Percentage of reproductive plants with sporophylls (A) andAverage Sporophyll Volume (B). Error bars are ± one standard error.ABAverage plant length increased steadily from June 2011 and peaked during October at Westhaven Marina and atCoromandel (Figure 15). The largest individual plants were recorded in October, with maximum sizes of 102 cm atWesthaven and 120 cm at Coromandel. Average length shows a steady decline from October as plants decay from theapex. Although no plants were seen in the survey area in Coromandel in February Undaria was seen on surroundinginfrastructure. A gradual increase in plant length is evident from February to April 2012 as new recruits appear.20