title: Ignoring discards biases the assessment of fisheries' ecological fingerprint.
abstract: Understanding the pressures of fisheries on the ecosystem is crucial for effective management. Fishery removals, or catch, are composed of both landings and discards. However, the use of discards data in studies investigating the effect of the fishing pressures is sparse. Here, we explore the individual contribution of both these catch components to the overall pressure of fisheries on the ecosystem metrics. Using Irish observer data, we compare the linear relationship between several ecological metrics calculated for landings and discards with those of catch. Our results show that in fisheries with high discarding rates, discards can drive the fisheries' ecological fingerprint and highlight the need to rectify landings-based estimates to make them representative of those of catch in order to gain a robust picture of the impact of fisheries.
authors.affiliation: Department of Zoology, School of Natural Sciences, Trinity College Dublin, Ireland.
authors.forename: Mafalda
authors.initials: M
authors.lastname: Viana
authors.forename: Luke
authors.initials: L
authors.lastname: McNally
authors.forename: Norman
authors.initials: N
authors.lastname: Graham
authors.forename: David G
authors.initials: DG
authors.lastname: Reid
authors.forename: Andrew L
authors.initials: AL
authors.lastname: Jackson
mesh_terms: D000818:Animals; D044822:Biodiversity; D003247:Conservation of Natural Resources; D004463:Ecology; D017753:Ecosystem; D004784:Environmental Monitoring / Q000379:methods*; D005398:Fisheries; D005399:Fishes / Q000502:physiology*; D007494:Ireland; D011157:Population Dynamics; D012044:Regression Analysis
keywords: biodiversity; catch; discards; landings; marine conservation