The Distribution and Abundance of Elasmobranch Fish in Tralee, Brandon and Dingle Bays in 2018-2019

Abstract

Surveys of skates and rays were undertaken in Tralee, Brandon and Dingle Bays in north Kerry during 2018 and 2019. The area was previously shown, from angling records and more recent shore surveys of egg cases, to support a high diversity of these species some of which are critically endangered in Ireland, the Atlantic or globally. Twelve species were recorded in the area and their geographic and seasonal distribution is described in this report. Their relative abundance in the surveys confirms their presence in the Tralee Bay area and the importance of that area as a refuge for them. Three of the species recorded, angel shark, blue skate and flapper skate are critically endangered globally. White skate was not recorded in the surveys but a single individual was captured separately in commercial tangle nets in 2018 in the area. This species is critically endangered in the Atlantic. Data from other broad scale fisheries surveys and fisheries sampling at sea, not reported here, confirm that these species are rarely found elsewhere. In addition, and in order of abundance, thornback ray, painted ray, sting ray, undulate ray, blonde ray, spotted ray, spurdog, tope and greater spotted dogfish were recorded. Endangered species of skates and rays are listed on various species red lists internationally and are prohibited species (from being landed) under Common Fisheries Policy regulations. The main source of mortality is from fishing. The current regulations, however, do not necessarily remove this source of impact because accidental by-catch and mortality can still occur. Populations that are at critically low levels locally are unlikely to be able to sustain this additional mortality and there is an ongoing risk of local extinction. Effective protection and restoration will need to consider additional measures such as marine protected areas or other mitigations of the effects of fisheries where they pose a high risk to the viability of local populations. Waters off north Kerry are important internationally as they hold some of the last remaining refuges for angel shark and white skate.