Assemblages of deepwater shark species along the north east Atlantic continental slope. (March 2020)

• Record Type: Journal Article
• Authors: O' Hea, Brendan; Davie, Sarah; Johnston, Graham; O' Dowd, Leonie
• Is Part Of: Deep sea research. Volume 157(2020)
• Publication Date: 2020-03
• Subjects: Deepwater sharks -- West of Ireland -- Squaliformes -- Apristuridae -- Porcupine bank -- Multivariate analysis; Oceanography -- Periodicals; Océanographie -- Périodiques; 551.4605
• DOI: 10.1016/j.dsr.2019.103207
• Languages: English
• ISSNs: 0967-0637

Abstract

Abstract: Significant variation in deepwater shark assemblages between those found in the 500 m depth band, and those of deeper waters is identified in the analysis of data from the northeast Atlantic continental slope and the northern slope of the Porcupine Bank. Deepwater shark data from four research surveys carried out between 2006 and 2009 yielded twenty-one deepwater shark species from five depth strata across three areas. It is suggested that a new grouping of sharks, "slope", be considered to reflect those species that are not easily categorised as either Shelf or Deepwater. This may have implications for assessment and management. Depth was identified as having a major influence on the variability of shark catch per unit effort (CPUE), whilst less variability was detected across the area or between years, indicating that depth based management rather than local or regional management measures may be more appropriate. Highlights: Multivariate analysis identified depth variation in deepwater shark assemblages. Depth has an important influence on the variability of deepwater shark CPUE. Legislation aimed at protecting deepwater sharks may not be detailed enough. A new "mid-depth" classification is needed to better describe slope shark species.