We have verified the use of a serial filtration method to isolate picocyanobacteria for analysis. We used eDNA metabarcoding to confirm the picocyanobacteria as members of the Order Synechococcales, Genus Cyanobium, specifically Cyanobium 6307. Fluorometric analysis using accessory pigments phycocyanin and phycoerythrin described periods of excess biomass, where the net growth rate model confirmed these conditions. The total anatoxin-a concentrations in the picocyanobacterial sample ranged from 0.0074 -6.41 µg•L −1 representing a 40-fold difference over the entire sampling season. Sampling frequency of every three days appeared to be an important factor in capturing these changes in anatoxin-a concentration. During a period of excess biomass, we were able to establish a linear correlation between cyanobacterial biomass and Anatoxin-a concentrations.

A recent fatality from a white shark bite in Massachusetts, U.S.A. has led local officials and members of the public to consider culling the population of gray seals in local waters. The seal population, which has been visibly increasing coincident with implementation of the Marine Mammal Protection Act, is thought to have attracted the white shark predators to the area. Were stakeholders to seek scientific evidence to inform a decision to cull, they would find little guidance. This study examines the scientific literature on culling and its impacts both on the species of concern and their ecosystems. Possible culling impacts are considered in the context of the biology and ecology of the Cape gray seal and white shark populations. Results are presented to inform decisionmakers about the feasibility, likely outcome and potential complications of a gray seal cull. The conclusion reached is that culling the Cape Cod gray seals is unlikely to abate the risk of human-white shark encounters on the Cape Cod beaches and could possibly have unforeseen consequences both for the local ecosystem and human activity.