A total of eight boats are involved in the fishery, all under seven metres, operating single handed and working from the tidal port of Hayle on the southern side of St Ives Bay in Cornwall.

The fishery takes place in the clearly defined inshore area, in depths of between ten and thirty metres, with mackerel moving parallel to the coastline, following the tidal currents.  The currents are predominantly in a Northeast and Southwest direction for the flood and ebb respectively.  Although the presence of mackerel during the summer months had been known of for many years in the area and occasionally exploited by crabbers for bait, no vessels had prosecuted the fishery on a continuous full time basis until 1995.

The port of Hayle is tidal and is only open for safe navigation three hours either side of high water, remaining dried out over the low water.  It therefore follows  that any fishing operation must take place either during one six hour high water period or for an extended period over and including the low water.  Prevailing weather conditions, sea state and ground swell and height of tide have to be taken into account and may effect departure time and available fishing time on the ground.   Depending on the time of day, the state of the tide, weather conditions and the catches from the previous day, the probable area, expected location and tracks of the mackerel shoals are estimated by the skippers.

The boats leave port to arrive in the area after steaming for an hour at six knots just after high water and proceed to spread out and search at two to three knots in an easterly direction until mackerel are located dropping back on the ebb tide.  The echo sounders are switched on immediately after leaving port and any electronic navigation aids are checked and calibrated against known marks, and are constantly monitored.  From experience several ‘tracks’ are followed and ‘favourite’ individual areas are examined first, working, in order of priority, from west to east and from tight inshore up to the cliff face in 10 metres depth to deeper offshore waters.     

In the summer fishery mackerel shoals consist of aggregations of small slow moving ‘bunches’ that can be found anywhere from the surface, through the water column to tight on the bottom.  Evidence obtained from the examination of faecal material, stomach contents and regurgitated food during the fishing operation suggest that the depth that mackerel are found is dependent on the food species being targeted and environmental conditions.  These shoals behave and appear to have different echo traces to those of the well documented winter mackerel fishery . 

A totally different fishing method has evolved, known locally as ‘the loop’,  enabling small boats by virtue of their high manoeuvrability and tight turning circles to actively target these small scattered shoals.  It is the development of this highly skilled  technique that has enabled the boats in this fishery to maximise their catch rate.