Preliminary results of an Ecological Risk Assessment for New Zealand fisheries interactions with seabirds and marine mammals

Citation
Waugh SM, Filippi DP, Walker N, Kirby DS (2008) Preliminary results of an Ecological Risk Assessment for New Zealand fisheries interactions with seabirds and marine mammals. WCPFC, Port Moresby, PNG
Abstract

An analysis was undertaken of the risk of adverse effects on populations of protected species due to fisheries interactions in New Zealand waters. The Ecological Risk Assessment (ERA) methodology developed as part of the work of the Western and Central Pacific Fisheries Commission was used as a guide to the work reported here. The report presents a preliminary Productivity-Susceptibility Analysis (PSA) depicting the likely encounters and relative likelihood of population effects due to interactions between fisheries (pelagic longline and troll) and 26 seabird and 2 marine mammal species. We derived species distributions from a pre-existing database which incorporates available sightings data, breeding localities, incidental catch records, and remote-tracking studies. Species distributions were then scaled by population size to give a relative estimate of density. We used these density distributions and maps of fisheries effort data to develop indices of species’ susceptibility to fisheries capture. Indices of productivity were then developed from biological information: lifetime reproductive output was calculated from age-at-first breeding, breeding frequency and clutch size; lifespan and age-at-first breeding were again used as indicators of natural mortality and inherent risk due to delayed maturity. The indicators of productivity and susceptibility were then plotted and the risk scores ranked, so as to describe the relative risk among species due to pelagic longline and troll fisheries.