The works done at sea for the Medits 96 survey have been conducted from the 1st of May 1996 till the 5th of August 1996. They covered the same areas as for the previous one, plus an extension in the Eastern part of the Adriatic Sea.

Nine vessels have been used for this survey. Eight of them are the same as for the ‘95 survey; one has been added (Kapetan Paraschos) to take into account the increase of the number of hauls in the Aegean Sea. The calendars of the survey are presented in the annex II. The survey has been conducted in the different regions using the same rules as for the ‘95 survey (cf. " Manuel des protocoles de la campagne Medits 95 "). A total of 1095 hauls have been made by the different teams in the whole area (annexes II to V).

At the end of the survey, all the data have been checked and validated by each of the teams, using a common specific program (the CHECKMED program). The data have been grouped to produce the common data bank. The data of each region have been sent back to each of the respective regional co-ordinators after this common validation. Furthermore, as for the previous ones, the corresponding computer files will be deposit in five places (to the EC-DG XIV and by each of the members of the Co-ordination committee) to ensure their protection.

Owing to the progress done by the different teams to manage the rough data, the procedure of grouping and validation of the data was finished by the middle of October, that means a very few months after the end of the survey. In these circumstances, a first global run to produce biomass/abundance estimators as well as length frequency distributions for the species included in the reference list might be made available to the Steering committee members for the end of October, to help the preparation of the biological analysis at a global level. Then, as it was done at the end of each of the previous Medits surveys, the set of computer files containing all the basic data (annex VI) have been deposited at the EC-DG XIV and the Co-ordination committee members’ offices for preservation.

Technical reports written by the respective national or regional co-ordinators are presented below. They set out the conditions whereby the survey has been conducted in their region.

The sampling cruise of the project Medits_ES/96, took place from the 01 to 29/05/96, starting in Málaga, using O/V "Cornide de Saavedra". The dates have had to be put earlier to the agreed dates due to the O/V calendar.

A total of 107 hauls have been made, 34 in the Alboran sea, 30 in the sector of Alicante and 43 in the Catalan sea. Scientific participants came from the laboratories of the IEO of Málaga, Murcia and Balearic islands; of the ICM of Barcelona and of the Universidad de Ciencias del Mar, of Las Palmas (Canary Islands). An italian biologist (Paolo Sartor) boarded during two weeks. For the Spanish part A. Esteban of the IEO of Murcia participated in the Medits_IT survey (M2, Sardinia), and E. Massutí of the Balearic IEO and M. González of the Málaga IEO boarded in the Medits_GR survey on board of the commercial ship "Kapetan Paraschos".

The biologist of the IEO of Málaga, María González, accomplished a stay of a week in the laboratory of Sète (France) to work in these topics of common interest for the Medits working group.

During all hauls a SCANMAR device was used to check the gear geometry. The trawl worked accordingly to the last year parameters and greater catches of pelagic species has been observed, as in 1994. It can be considered that the weight of the bottom chain is sufficient and that it is possible to change the vertical opening, increasing it for the deepest hauls.

As far as possible all stations have been made at the same positions as in the previous years (Manuel des protocoles). Some haul positions are new but very closed from the previous corresponding positions, mainly for the deepest hauls. Some positions in the stratum 30-50 m have been changed due to the existence of artificial reefs or to problems with the artisanal fishermen’s nets. The trawl has not suffered important damages except some mesh’s break in hard grounds (coral, stones, etc.). Among the 107 hauls, only three resulted in empty trawl because of the currents or unforeseen obstacles.

The treatment method of the catches and, as a rule, of the obtained material was the same as in the previous surveys: determination of all the genus and species of vertebrates and invertebrates, numbering and weighting of all caught species, biological examination of the main species and of some others of national interest or for particular projects. Samples have been taken for genetics and studies on pollution by heavy metals and hydrocarbons. Some crustaceans and cephalopods have been studied and kept for the collections and subsequent studies. Some observations have been made to study on behaviour and data of sightings of sea birds, cetaceans and turtles have been collected.

The data were input in our own data base (CAMP) using the DAME program. In the laboratory, these data were edited and checked with the CHECKMED program. Abundance indices and length frequencies have been calaculated using the INDMED program.

The most abundant target species (in number) were, by order of importance: Micromesistius poutassou, Merluccius merluccius, Trachurus trachurus, Helicolenus dactylopterus, Trachurus mediterraneus and Pagellus acarne.

The Medits FR survey took place from the 27th of May to the 26th of June. The first part of the survey (27/05 - 06/06) has been conducted on the eastern coast of Corsica and the second part (07/06 - 26/06) in the Gulf of Lions. During the whole survey, the weather conditions were very good except for two or three windy days.

The geometry of the trawl has been monitored during the whole survey using the SCANMAR. As far as possible the rigging accorded with the latest version of the "Manuel des protocoles", but for some deep hauls (more than 300 m) the sweep length has been set to 200 m to ensure the good positioning of the trawl on the sea bed. This problem, already encountered last year, should be addressed to the gear technologists group.

Nevertheless and in general, the gear specifications, as indicated in the "Manuel des protocoles", lead to a good efficiency of the trawl. At each haul it is however important to wait that the trawl geometry be well stabilised before to decided the beginning of the haul, even if this waiting time can seem rather long.

This year very few damages to the gear occurred during the survey. The most important were in Corsica. As mentioned in the last year report, the shallowest strata in Corsica (13101 and 13106, between 10 and 50 m) have been considered as not trawlable due to very large quantities of algae, sea urchins and eel grass (Posidonia sp.). These strata have hence not been worked. Furthermore, in the whole northern area, off the Cape Corse, the grounds are too hard and rocky to allow trawling and some severe damages occurred in 1995 in that area. Moreover, the Corsican industry does not work on these grounds. So it is envisaged for the future surveys to reduce the northern strata and to set their northern limit at most 10 miles north of Bastia.

During the '96 survey, 89 hauls have been made among which 86 were valid: 64 in the Gulf of Lions and 22 in Corsica. As explained above, in the eastern Corsica, the haul distribution has been changed compared to last year, first to take into account the difficulties to trawl in the shallowest strata and second to avoid to have too few hauls in a given stratum.

For all hauls, the ichtyometre has been used, together with the DAME program written by G. Delmas. This allowed to point out a bug in the program and this has been corrected immediately after the survey. Apart from some errors due to this bug, the data files were error free at the end of the survey.

In addition to the normal biological observations, a systematic inventory of waste products present in the codend (glass, plastic, metal, etc.) has been made. This inventory showed the importance of waste concentration near the biggest harbours (Marseilles, Bastia) and on the ferries routes between Corsica and the mainland.

The M1 operative unit sampled in the Ligurian Sea (strata 13201 -13205), the northern Tyrrhenian (strata 13206 - 13210), the central Tyrrhenian (strata 13211 - 13215) and the southern Tyrrhenian (strata 13216 - 13220), although this terminology does not reflect the actual geographical limits of the Tyrrhenian Sea.

In the M1 region the 1996 Medits survey was carried out from June 2 to July 25 using the professional trawler "Francesco Padre". A total of 153 hauls were carried out. The bad weather condition during the end of June and the first week of July has affected part of the survey resulting in a delay in the completation of the campaign. Moreover no particular technical problems were met. Few damages to the gear occured during some coastal hauls (stratum A) in the Ligurian sea due to very large quantities of sea urchins and other benthonic species and Posidonia oceanica and in 1-2 deep hauls of the northern Tyrrhenian sea due to the presence of hard substrata. With the help of a GPS plotter it was very easy to trawl again on the last years coordinates.

A SCANMAR equipment was avaible only for a few days test and hauls duration was recorded according to the recommendations of the Medits protocol.

Weight, measure and maturity of the sampled fish have been carried out on board. Data were recorded on computer on board using the DAME program and checked using the CHECKMED program in the laboratory.

From the 19^th of June to the 2^nd of August a total of 125 hauls were carried out with the fishing vessel "Nuovo Splendore" in seas surrounding Sardinia. A total of 31 fishing days, 2 days of bad weather brake and 12 days of technical break were spent.

From the 18^th to the 22^nd a Spanish scientist, Antonio Esteban, has been on board and in our laboratories, while two scientist from the unit M2, Murenu M. and Sabatini A., took part on the Greek and French surveys respectively.

This year the fishing activity has been conducted without particular problems, excepted for the bad weather condition during the first period of the survey. Few hauls were repeated because the net worked badly on the bottom. We lost a net at 500 m of depth, but fortunately 5 days later it was fished again by the "Carlo Recchi", an other commercial vessel.

No SCANMAR equipment was available.

A total of one hundred and seventy-five species were identified: 125 fishes, 31 crustaceans and 21 cephalopods.

Comparing the yield in each stratum (133a,b,c,d,e,f,g), we can observe a difference in biomass values between the west and south coasts (133d,e,f,g) and the east coast (133a,b). Generally for most species the highest indices were calculated in the western stratum, though some species were also abundant along the north and north-east coast.

The M3 zone encompasses two totally different sub-zones; no joint analysis of results seems sensible, but the technical problems met can be considered jointly instead, as "fishing unit" is the same.

The survey was carried out using the professional trawler Sant’Anna. The first sub-zone covered was the Sicilian Strait from 31^st May to 12^th June 1996. Four people from ITPP were on board. On 17^th June the people from Messina came on board F/V S.Anna to cover the part of South Tyrrhenian Sea facing northern Sicily until 24^th June. On 25^th June, research workers of COISPA (Bari) started surveying the Southern Tyrrhenian Sea facing Calabria and then Central Tyrrhenian Sea facing Campania Region. The survey ended on July 5^th.

Hauls performed were 56 in the first sub-zone, 28 in the second and 57 in the third one. The geographical position of one haul in sub-zone M3a and three hauls in sub-zone M3c was displaced in 1996 survey due to problems regarding the bottom nature.

The same gear was utilised throughout, modified as from Medits ‘95 protocol from the technicians of IRPEM-Ancona: number of floats, lashing of groundrope, insertion of a chain on groundrope. The "racasseur" was not mounted instead. As regards the maintenance of the gear, some damaged parts were substituted before and during the survey. In fact, five hauls were carried out utilising the reserve net due to a damage which occurred to the net during a haul on rocky bottom.

A SCANMAR equipment was not available, but haul duration was recorded according to average effective time on bottom as from previous trials with SCANMAR by IRPEM-CNR technicians.

Processing of biological items was accurately performed according to Medits ‘95 protocol, and a huge amount of Lepidopus caudatus and Trachurus spp. was observed. Moreover a strong decrease in the catch of Micromesistius poutassou was evident.

The Medits-IT M4 & ALBANIA 1996 survey was carried out from 3/06 to 27/07 (55 days, including stand-by and transferring).

The survey lasted 19 days in Ionian areas (Cape Passero-Cape of Otranto), 24 days for south-western Adriatic areas (Cape of Otranto-Vieste) and 12 days for south-eastern Adriatic areas (S. Johan - Saranda).

During the survey 186 hauls were carried out (74 in the Ionian areas, 72 in the south-western Adriatic areas and 40 in the south-eastern Adriatic areas).

The trawler "Bianca Maria" was used to the whole area; the IRPEM technologists set up the fishing gear at the beginning of the survey.

Sometimes the work at the sea was hampered by weather conditions or bottom irregularities mostly in Ionian areas); one door was lost near Roccella Jonica (Calabrian coast).

For the first time, the research includes the whole area which is located north of the line Gargano-Kotor and gives complete informations.

The survey has been undertaken in a close joint-work of the three national teams of scientists participating together to the sampling operations.

In all, 136 hauls have been carried out according to a sampling design aimed to get both an homogeneous and random spatial allocation. The whole area has been divided into 20 per 10 nautic miles rectangles and the haul to be done in each rectangle has been selected at random. Due to the geomorphological features of the middle and high Adriatic bottoms, most of which are characterized by slight slopes, this sampling scheme made possible to preserve a satisfying proportional-like allocation in the depth strata. In the basin, it seems that the species distribution is related to some factors like the nature of sediments and the biocoenose instead of depth.

The surface amounts roughly at 92 260 km². The stratification plan is reported in tab. 1. The evaluation of the strata surfaces couldn't be very accurate for two problems linked to the Croatian zone: the high number of islands and bathymetric lines which, in different maps, develop in slight different patterns.

Tab. 1 - Stratification plan. Medits '96

The G1 Greek unit has been sampled in the North Aegean Sea (North of 38 N), using Kapetan Paraschos, a commercial trawler, from the 19th of June to the 29th of July, with 1 day of experimental hauls, 31 days at sea, and 9 days of break.

The weather conditions have affected the duration of the survey.

The fishing activities was conducted with some difficulties due to:

1. doors rigging (the upper small chains were enlarged by 10 cm in order, to stabilize the doors and position them vertically, since they were getting continuously into mud, especially at deeper waters),
2. problems in finding the depths given at the initial co-ordinates of the hauls, and
3. the fact that most hauls were new.

In total, 64 hauls have been carried out during this cruise. Nine of them were repeated twice (4 due to doors sinking into mud, 2 due to the net stroke on shoals and 3 due to the misfunction of the net). Three of the stations sampled in 1995 have been transposed because of the morphology of the sea bottom and 1 of them has been removed.

No SCANMAR equipment was available, but hauls duration was recorded according to the recommendations (6.1 - Shooting suggestions) of the Medits Trawl Tests in the Adriatic Sea and in Tyrrhenian Sea in 1995 and to the results of our experimental hauls.

Two Spanish scientists, Enric Massuti Sureda and Maria Gonzalez Aquilar have taken part on our survey for 2 days.

Weight, length and maturity of the sampled fish have been recorded on board. In the laboratory data were recorded on computer using the DAME program and checked using the CHECKMED program.

Abundance indices were calculated for target species only.

The species from the reference list, which were most abundant in weight were, in order: E. encrasicholus, S. pilchardus, M. poutassou, R. clavata, M merluccius, L. budegassa, I.coindetii, T.minutus capelanus, P. longirostris, L. caudatus, S. canicula, A.sphyraena, L. piscatorius.

Considering the number of individuals the most abundant were, in order: S. pilchardus, E. encrasicholus, M. poutassou, T. minutus capelanus, A. sphyraena, P. longirostris, T. trachurus.

The most widely distributed species were, in order: M. merluccius (in 53 of the 64 hauls), L. budegassa (47 hauls), I. coindetii (45 hauls), P. blennoides (41 hauls), P. longirostris (38 hauls), S. canicula (37 hauls), T. trachurus (33 hauls), N. norvegicus (31 hauls), R. clavata (30 hauls), M.poutassou (30 hauls).

According to our proposal for Medits-GR 96/97, the increase of the number of sampling stations in the Greek Seas and the involvement of the Fisheries Research Institute (FRI) of Kavala was scheduled. For this reason, in the 1996 sampling cruise two vessels were used. One hired by FRI for the northern Aegean Sea (zone G1) and one hired by NCMR and IMBC for the rest of the regions (zone G2).

In zone G2, the sampling cruise started on 1/6/96 and ended on 4/8/96. IOANNIS ROSSOS was used, a commercial trawler that has also been used during Medits-GR/94 and 95. Before the beginning of the cruise, the assemblage of the fishing gear was inspected by one delegate of NCMR and one of FRI, in order to assure the observance of the Medits protocol and the harmonization between the two Institutes. The functioning of the gear was tested in the Evoikos Gulf.

During the sampling, bad weather conditions and damage in the ship’s engine resulted in the omission of a small number of hauls (mainly in the southern Aegean Sea) and to a delay in the completion of the campaign. Furthermore, a difficulty to make some new hauls over obstacles on the bottom (cables, rocks etc.) led to the transposition of some stations. It must also be mentioned that in the region of Argosaronikos the trawling was difficult and the gear was often damaged because of the rocky substrate, but also because of the large amount of bulky rubbish found in that area.

During the 1996 sampling period, a SCANMAR system was used by NCMR having the following sensors: depth sensor, trawl speed sensor, distance sensor and trawl sounder (for vertical opening and clearance). The gear showed a generally homogenous performance. The horizontal opening ranged between 15 and 18 m, whereas the vertical one ranged between 1.9 and 2.6 m. The speed generally ranged from 2.9 to 3.1 knots. The above values did not show remarkable differences between the different depth strata. An observation worth noticing is that the gear presented a short duration oscillation of 0.3 m. However, during the 1996 cruise the gear showed a better performance probably due to the higher attention given to its fit out. Also, the functioning of the SCANMAR with all the sensors permitted a better knowledge of the performance of the gear.

The electronic observation and recording of the track of the hauls was conducted by means of a GPS and of a PC using the appropriate software. In this way, there was a complete representation of the haul (beginning, end, change of direction) and hence a more accurate estimation of the swept area and of the fish-stock abundance parameters.

An electronic ichthyometer was used on board by NCMR for the measurement of the length of the target fish species and the collection of the biological data. A software was developed for the transfer of the raw data of the ichthyometer, their validation and their storing into the NCMR database. It must be reported that the ichthyometer is not rapid enough in its use, however its new version seems to be improved and more time saving.

___

Appendices

Appendix II: Calendar of the survey

Appendix III: Boarding tables

Appendix IV: Stratification scheme

Appendix V: Sampling scheme

Appendix VI: Computer files