ICES CN 2013 N:22 - Poster

Experimental jigging with light attraction on European flying ( sagittatus ) in Icelandic waters with notes on earlier trawl-fishing trials and traces of the species annually recorded in bottom trawl surveys.

Einar Jónsson 1) and Ólafur A Ingóflsson 2) 1) Marine Research Institute (MRI) Skúlagata 4, 101 Reykjavík, Iceland e-mail: [email protected] 2) Marine Research Institute Branch, Árnagötu 2-4, 400 Ísafjördur, Iceland e-mail : [email protected]

Summary In September 2010 The Marine Research Institute (MRI) conducted an expedition aimed at fishery trials for squid ( Todarodes sagittatus ). A research vessel (186 BWT) was equipped with modern jigging machines as well as two kinds of light-tools to attract the squid and a relatively vast off-shore area was covered. The impetus for the experiment were growing signs of a comeback of the squid but this time more off-shore above the slopes of the Icelandic continental shelf rather than in in-shore waters as in the earlier days. In this poster the results – not very promising in terms of squid catches – of the jigging trial (methodology, and area covered) are presented. The poster describes to some extent results of earlier fishing trials with pelagic trawls and biological parameters (length, weight maturity) of the squid sampled are shortly mentioned. Traces of Todarodes are annually found in the Icelandic autumn bottom trawl surveys especially after the year 2000 culminating in 2008. Results from squid recorded in these surveys are also partly presented. Attention is also paid to the newly started (2010, 2013) registration of Todarodes in the Icelandic fish-statistic through by-catch of the species in the far off-shore fisheries.

Introduction For a century or so the European flying squid was regularly caught in fiords and bays with hand-jigs and was quite important source of bait for the long-liners until migration of the species came to such a still-stand – some 35 years ago – that no commercial fishery was possible any more. The Icelandic Todarodes catch statistics are only available for years after 1959 but on the average the species migrated to the Icelandic coast only every second year. After 1966 European flying squid has only migrated twice to the Icelandic coast (1979, 1984) to such an extent that major fishery was started – all time annual catch-record 1984 1634 tons. Since 1979 the MRI has kept a close watch on the European flying squid, (a data bank of 3393 individuals since 1982), Figure 3, mainly via various multipurpose trawl surveys. Furthermore, 3 expeditions, using commercial vessels have been conducted in which pelagic trawls were used for fishing trials on squid. As mentioned, small traces of the squid have been recorded annually in The Icelandic autumns bottom-trawl survey, mainly on or above the Icelandic continental slopes towards SW but also in far offshore areas west of the Reykjanes-ridge where fishery on deep sea redfish is conducted (Jónsson E 1998). In autumn 2008 the recorded traces on the south and southwest slopes were unusually prolific and fishing trials with jigging machines and light attraction were then initially planned.

Material and methods From the very beginning it was decided that this time the experimental fishing trials would be carried out with mechanical jigging machines and light attraction. The fishing gear consisted of two electrical (220 W) automatic DNG jigging machines (Icelandic made) fitted with squid program (Figure 2). As the squid jigs consist of hooks without barbs, jerking of the line, i.e. the standard jigging action of twine going up and down, is not feasible. Such movements would only make the pray (the squid) fall off the jig’s hooks. To imitate the jerking movements the line is pulled in at different speed. A computer controlled power drum produces this effect by pulling in the twine at different speed. Furthermore, many jigs (lures) are attached in a row on the same line with an interval of some 70-80 cm. To avoid entanglement of the jig-hooks on the power drum, the method used in this experiment, is to let the jigs never be wound onto the drum. Instead of placing the jigging machine at the same side of the boat (starboard) from which the twine goes overboard it was placed on the other side of the boat (backboard) and the twine goes via gunwale rollers on the starboard side down to the sea. Thus the twine with a row of jigs can be wound aboard not entering the drum corresponding to the distance across the boat; in this case 6 m onto which seven jigs (lures) were attached. Another jigging machine was placed close to the starboard gunwale and a twine with 14 jigs (12 m long) was via rollers let across the boat and back again and overboard. A net-wire recovery trays were used, protruding from the gunwale in a 45º angle with two rollers at each end. Thus when the line was hauled in it would be bent from the vertical up position to a 45º down position and the squid would be unhooked and slide aboard via the recovery tray into a box or small open container on the deck. The jigs themselves had all barbless hooks in double crown-sets. In the fore jigging machine with seven jigs, the luring silicon rubber bodies were red and non luminescent. On the other 14 jigs machine at the aft, the twine was fitted with multicolor luring bodies, both luminescent and non luminescent. The ship was fitted with four 2000 watts light bulbs suspended from steel cables (at intervals of ca 3 m) and ca 2 m above and inside the gunwale on the starboard of the ship, thus creating a zone of shadow and zone of illumination in the water below the vessel, extending outward from the gunwale in a ca 30º - 40º angle. Secondly the ship was fitted with one 5000 watts underwater lamp with a 300 m long electrical power cable. According to Japanese sources Japanese jigging vessels seldom use underwater lights below 300 m (John R. Bower and Taro Ochii 2005). The vessel was also fitted with huge parachute-like sea anchor to slow drift and stabilize the boat. No need was found to apply this equipment during the expedition. The experiments were aimed at the “traces” of Todarodes which had been recorded annually above the continental shelves, both relatively “large” squid and “small” squid (Jónsson E 2009). The experiments took mainly places during the dark night and sometimes during early evenings when the daylight had not yet vanished. The underground light was first lowered as deep as possible (300 m) and after a time of 5-10 minutes it was raised slowly usually with some short intervals. If the daylight had dwindled by the time the underwater light was visible from above the light-bulbs aboard were lit and jigs were lowered down towards the underwater-light and jigging started. When the underwater light was clearly visible (20-30 m depth) it was turned off and hauled aboard and jigging was continued within what was believed to be the range of the aboard lights (40-30 m downwards). Sea-water depth at different locations varied from 100 to 500 m and the jigs were sometime (at medium depth or less) lower down to the bottom in the beginning of jigging.

Results and discussion Seven stations deep off the Western Fjords where trawlers had recently reported Todarodes as by-catch and six stations west of Iceland yielded no squid. Due to bad weather the slopes of the Reykjanes-ridge which were promising (surveys) were left out. Instead fishing trials were carried out (13 stations) on the slopes south of Iceland - ca 17º00 to 23º00 W longitudes. One station (Figure 1) yielded 3 specimens between 01:00 and 02:00 hours. Two of the specimens were of the “small” autumn migration size; DML 22 and 26 cm; the third one of “large size”; DML, 40 cm. The length of Todarodes measured during the last decade by the MRI is varying from 15- 45 cm and all are immature (Jónsson 2009). The meagre results of this jigging expedition can obviously not be interpreted in other way than negative. The squid findings in the Icelandic autumn surveys are mainly one or just several specimens per haul when squid is recorded. It must therefore be concluded that the squid caught are nothing but traces regardless of fishing gear and little or no school formations take palace. The observations of trawlers on the Hali-bank in September 2010 where a considerable amount of small Todarodes (DML 15-30 cm ?) appears to heave been present for some time, however, appear as interesting and promising sign of a possible comeback. The newest development in Icelandic squid catching history is that in 2010 Todarodes showed up again in the official fishing catch statistic having been almost absent there since 1979 and 1984. In 2010 51 tons of Todarodes were caught as by-catch by vessels fishing blue whiting with pelagic trawl. Only few vessels were involved and one vessel alone caught 65% of the reported catch in spring (April). Investigations led to the conclusion that most of the squid had had not been caught in Icelandic waters but ca 100 km south of the Faro Islands and was landed there. In 2013 reported squid of Icelandic vessels is 14 tons. Few vessels catching blue whiting are again in involved, using the same gear at the same time of the year. The exact positions of the 2013 squid by-catch are still unknown but the same general area as in 2010 is to be assumed. This time the catch, however, was landed in Icelandic ports. Alas, this by-catch went more or less unnoticed by researchers until afterwards. No samples are therefore available and hence no biological measurements.

Figure. 1. Experimental jigging with Figure. 2. Deck view of the gear on the Figure 3. Todarodes samples of the light stations (26), red station yielded. illuminated jigging vessel. MRI 1982-2012. Green cicle Todarodes a small catch. bycatch area of blue whiting trawlers

Rererences John R. Bower and Taro Ochii 2005. The red flying squid ( Ommastrephes bartramii ): A review of recent research and the fishery in Japan Fisheries Research. Volume 76, Issue 1. Pages 39-55, October 2005. Jónsson E.1998. Study of European flying Squid Todarodes sagittatus (Lamarck), Occurring in deep Waters south of Iceland, ICES Them Session on 1998; CM 1998/M:48. Jónsson, E. 2009 European flying squid (Todarodes sagittatus ) in Icelandic waters; an overview of exploitation (occurrence) & research on the species in this region; poster presented at CIAC Symposium in Vigo, Spain, September 2009).