Basking shark fisheries have been historically characterised by a boom and bust relationship-giving rise to the belief that basking sharks have a low annual population uptake, estimated at 2- 10% annually (Compagno, 1984). However a number of studies have attempted to draw correlation’s between basking shark abundance and long term zooplankton decline. This correlation is reported to be a contributing factor in the sudden changes in localised basking shark populations over short periods of time (Sims, 2000).
It is suggested that Irish basking shark target fisheries over exploited the localised basking shark population in the 1950’s and 60’s leading to a collapse in the target fishing of basking sharks (McNally 1976, Sims & Reid 2002).
There are currently no population estimates for basking sharks within Irish waters. There are no measurable data sets to indicate population expansion or contraction trends, there is no research on the behavioural/feeding habits of basking sharks within Irish coastal waters, their spatial and temporal distributions or the major factors influencing these practices (Berrow, S.D., 2008, Speedie, 2003)