Adriatic Expedition September 2013

Introduction

This expedition was undertaken between September 20th – 29th to carry out DNA sampling and tagging on blue sharks for Dr. Alen Soldo of Split University, and Dr. Les Noble of Aberdeen University.

Expedition Report September 20th - 29th

Personnel and Acknowledgements

Organisers - Shark Conservation Society.

Expedition leader - Richard Peirce.

Catering, shorebase, first aid - Jacqui Peirce.

Videographers - Richard Peirce, Sarah Han-de-Beaux

Scientific advisor - Data being gathered for Aberdeen/Split University

Volunteer researchers - Tony Bennett, Emma Doran, Guy Munnings, Jeff Van Der Hulst, Sarah Han-de-Beaux, Andy Sweeney (sadly

although he made a full financial contribution A. Sweeney missed the expedition due to complications over his flights.

The Society would like to thank

• Vlado Stevic
• Neda
• Christina
• Denis
• Alen Soldo

Objectives

The objectives of the expedition were threefold:

• Collect blue shark DNA samples for Dr. Les Noble of Aberdeen University
• Return tag up to 10 blue sharks for Dr. Alen Soldo of Split University
• Collect more data from the previously identified blue shark nursery area off Dugi Otok (Kornati) to facilitate the publication of a joint paper Soldo/Peirce, and the closure of this area for a certain time of the year to all fishing

Preparation and Planning

As for past expeditions the Society is very grateful to Vlado for arranging all the at sea logistics prior to our arrival, and to Neda and Christina for the shore base.

Sites/Work Plan

The sites worked are as listed in the daily reporting that follows, but it should be noted that all sites visited were sites that in the past had produced blue sharks in response to chumming activities.

Boats

As for the previous expedition the Society chartered the Eudi with the owner as skipper and Vlado as crew.

Daily Report

Saturday October 21

A general preparation day sorting out bedding, provisioning, chum, diving equipment, and familiarising the team with the work they will be doing.

Sunday October 22

We steamed out of Murter at 11.30 and were on station at our first chumming site off Dugi Otok by 14.30. The chum was in the water by 15.15 and we drifted over exactly the same location where we had found numbers of blue shark juveniles in 2010. Three teams worked 2 hour shifts round the clock until 07.11 on Monday morning.

Location - N 43’49.449 E 15’12.056

Time chummed - 16 hours (less short times to move location through the night)

Species sighted - Stingray, squid, needlefish

Conditions - Sunny, little wind, flat seas

Results - None

Monday October 23 

The day started with a short drift inshore two miles up the coast from our last position which once again yielded no results, and we stopped chumming at 12.30 and returned to Murter arriving at 15.30.

Tuesday October 24

The team awoke at 06.00, we left the shore base with Vlado just after 08.00, and left Murter at 11.00 steaming at 7 knots to Jabuka. The distance to Jabuka is 55 miles and we arrived at 15.45 and had the chum in the water at 15.55. Our first site was about 5 miles short of Jabuka and we chummed all night. We hardly moved during this period due to very little current, flat calm sea, and no wind. This site had produced several blue sharks when we last visited it. At 08.00 after breakfast on the 25th we left.

Location - N 43’21.690 E 15’30.077

Time chummed - 15 hours

Species sighted - Sunfish, tuna, squid, needlefish, bait fish – no sharks

Conditions - Flat calm, windless

Results - No sharks

Wednesday October 25

After breakfast we moved to Jabuka and Vlado took Eudi close to the island, so that everyone could get a good look at it, and then we took up station about 3 ½ miles to the west of Jabuka, and chummed all day until the increasing sea state made it too dangerous to work and we moved to the shelter of Svetec Island. We had dinner in the shelter of the island and chummed all night moving 3 times as we drifted towards the island.

First location - N43’04.258 E15’30.170

Time chummed - 4 1/2 hours

Species sighted - None

Conditions - Sea state increasing

Results - No sharks

Second location - N43’08’327 E15’28.858

Too much swell, moved to

Third location - N43’02’463 E15’43.055

Time chummed - 14 hours less short periods when we had to move back offshore

Species sighted - None

Conditions - By 07.00 the sea state had reduced and was flat calm once again

Results - None

Thursday October 26

We left the Jabuka area at 09.00 heading for Bisevo which is where a large fleet of some 60 small boats were engaged in the annual game fishing competition. A friend of Vlado’s met us prior to arrival having brought out more sardines. The idea behind selecting this location was that (a) we had caught sharks here before and (b) the angling fleet was putting a lot of chum in the water which should have attracted predators. We arrived just after 13.00 and chummed various locations around the angling fleet until 17.00. At 17.00 we started steaming back to Murter as everyone was tired having been at sea working round the clock for three days.

Location - N43’34.448 E15’31.869

Time chummed - 4 1/2 hours

Species sighted - Various game fish and bait fish

Conditions - Sea state slight

Results - None

Friday October 27

The plan was to return to the area off Dugi Otok as this would enable us to tick all our boxes if we found sharks. We left Murter at 15.30 and on the inside of the island chain on the way out saw some common dolphins around tuna pens. We were on station by 19.56 and chumming immediately. Once again we chummed all night with no result and left at 08.00 the next morning.

Location - N43’49.752 E15’12.530

Time chummed - 12 hours

Species sighted - Various game fish and bait fish

Conditions - Sea state slight

Results - None

Saturday October 28

We started teaming to our next location at 08.00. We were headed for a site 5/6 miles SW Blitvenija which had in the past yielded several blue sharks. We did a very good long drift working over familiar blue shark ground and left at 17.00 headed back for our blue shark nursery area. Once again no sharks of any description responded to our extensive chumming efforts.

First Location - N43’31.892 E15’30.990

Time chummed - 5 1/2 hours

Species sighted - Various game fish and bait fish

Conditions - Sea state slight

Results - None

Second Location - N43’49.894 E15’11.473

Time chummed - 5 1/4 hours

Species sighted - Various game fish and bait fish

Conditions - Sea state slight

Results - None

Once again we had chummed all night in the nursery area and once again there was no result. We arrived back in Murter at 03.00.

Sunday October 29

The last day of the expedition and generally a relaxing and chilling out day. The volunteers were understandably puzzled by the lack of sharks but a possible explanation had been discovered last night when on the radio we heard that a Norwegian seismological survey company had been working in all the areas we had been chumming. It is widely accepted that this type of activity affects cetaceans and the expedition members by now had the firm suspicion it must also have affected sharks.

Conclusion

As mentioned earlier in this report no sharks were encountered which was very disappointing and disheartening not only for the volunteers but also for those for whom we had been collecting data. Not finding sharks in one or two locations would not have been unusual, and would not have rung alarm bells. However not finding sharks in any locations where there had been past encounters, cannot be explained by over fishing or any other common explanation. Our strong assumption is that somehow the seismological activity got rid of the sharks in the area as it had the cetaceans. If any researchers are aware of anything being published on the affects of this type of exploration on shark populations, then we would be extremely grateful if they would contact the Society. A total of over 90 hours chummed with no results in various areas that had always produced sharks needs some explaining, particularly when one adds the fact that an enormous amount of chumming was done by the angling fleet during their competition, and they saw no sharks either.