The works done at sea for the Medits 97 survey have been conducted from the 9th of May to the 14th of August 1997. They covered exactly the same areas as for the Medits 96 survey.

Nine vessels have been used for this survey. Eight of them are the same as for the ‘96 survey, one been replaced, for the survey in the North and Central Adriatic (New vessel: Principessa I). The calendar of the survey is presented in the appendix II. The survey has been conducted in the different regions using the same protocols as for the ‘96 survey (cf. " Manuel des protocoles de la campagne Medits 95 "). Nevertheless, a few complements have been introduced for this survey following the recommendations of the technologists (see appendix VII). A total of 1100 hauls have been done in the whole area (appendix IV).

The data have been validated using the same procedure as for the previous survey (particularly by using the CHECKMED program). Furthermore, also as for the previous surveys data, the corresponding computer files are deposited in five places (to the EC-DG XIV and each of the members of the Co-ordination committee) to ensure their protection.

All the basic data were available to prepare a set of tables and figures to be used by the working groups which met in Madrid early in November 1997 for a common analysis of the survey results.

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 report is completed by a series of appendices which include all the technical information to characterise the survey and to identify the activity of the programme during the year.

The Medits ES survey took place from the 9^th of May to the 5^th of June. In all, 102 hauls have been carried out with the oceanographic vessel "Cornide de Saavedra", 34 in the Alboran sea, 25 in the Alicante sector and 42 in the Catalan sea. Scientific participants came from the laboratories of the IEO of Málaga, Murcia and Balearic islands; of the ICM of Barcelona; of the Universidad de Ciencias del Mar of Las Palmas (Canary Islands); of the Universidad of Alicante and of the Universidad de Sevilla. The weather conditions were good.

During all hauls a SCANMAR device was used to check the gear geometry. The trawl worked according to the recommendations of the Medits protocol. In general, the catch of pelagic species were smaller than the last year.

During the ’97 survey, 111 hauls have been made among which 100 were valid: 9 hauls were not entered in the accounts because of the hooking and breaking of the net. These particular problems have supposed the waste of 3 days of the survey employed in to repair the net. Among the others 102 hauls, only two resulted in empty trawl because of the currents or unforeseen obstacles. In general the hauls position was the same that the last year, except some positions that have been changed due to the existence of artisanal nets. In addition to the normal hauls, three nigh hauls were made in the stratum A.

Determination of all species of vertebrates and invertebrates; take of number and weight of specimens of each species; measure and maturity of the main species and of some others of national interest have been carried on board. As others years the rubbish was classified, numbered and weighted. Also on board the data were recorded in our own data base (CAMP) and in the DAME program. In the laboratory the data base was checked using the CHECKMED program, and the abundance and the length frequency distributions were obtained with the INDMED3 program.

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

The Medits FR survey took place from the 26th of May to the 28th of June. The first part of the survey (26/05 - 30/05) has been conducted on the eastern coast of Corsica and the second part (08/06 - 28/06) in the Gulf of Lions. The gap between the two parts of the survey has been due to a general failure of the hydraulic system of the vessel which prevented us from any fishing operation. Furthermore, the repairing has needed one week, hence the number of haul in Corsica has been limited to 13. 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". During the last three days of the survey, some hauls have been trawled twice, once with the tickler chain and once without. This experiment has been done to assess the efficiency of the chain, especially for the catch of flatfish. Its results should be communicated later to the Steering Committee and/or during the next year symposium.

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 decide 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 previously, 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.). Furthermore and as explained in the last year report, for practical purposes the trawlable parts of the north most strata in Corsica have been reduced and their northern limit have been set at 10 miles north of Bastia, but it does not affect the total surface of these strata for the analysis.

During the '97 survey, 89 valid hauls have been made : 76 in the Gulf of Lions and 13 in Corsica. The rather low number of hauls in Corsica has been due to the above mentioned difficulties.

For all hauls, the MICREL ichtyometre has been used, together with the DAME program written by G. Delmas. This allowed to point out some bugs and defects in the program and it is expected that they will be corrected shortly. The data files have been checked and when necessary corrected immediately after the survey.

Samples have been made for genetic studies asked by various scientific bodies : University of Cork - Ireland - Dr P. Galvin (Micromesistius poutassou, Trisopterus minutus capelanus), CEFAS - Lowestoft - GB - Dr R. Millner (Trisopterus minutus capelanus) and University of Montpellier II - France - Dr D. Adam (Nephrops norvegicus, Parapenaeus longirostris). The results of these studies are expected in 1998 and the source of the samples will be mentioned by the various authors.

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.

In the M1 region the 1997 Medits survey was carried out from June 3 to 31 July using the professional trawler "Francesco Padre". A total of 154 hauls were carried out among which 153 were valid. The bad weather condition during the end of June and the first weeks of July has affected part of the survey resulting in a delay in the completion of the survey. A total of 37 fishing days, 11 days of bad weather brake and 13 days of technical break were spent.

No particular technical problems were met during the survey. As far as possible all stations have been made at the same positions as in the previous years. Only an haul is new but very closed from the previous corresponding position because of a dangerous presence of coral.

Scientific participants came from the laboratories of the Consorzio Interuniversitario di Biologia Marina di Livorno, of the Centro Regionale Idrobiologia e Pesca di Livorno, of the University of Genoa and of the University of Rome. Two Italian biologists (V. Crespi and M. Manca) participated in the Medits_FR and Medits_GR surveys respectively.

The data were input on computer on board using the DAME program and checked using the CHECKMED routines. Abundance indices and length frequencies have been calculated using the INDMED4 program.

The species from the reference list which were most abundant in weight were, in order: Merluccius merluccius, Eledone cirrhosa, Phycis blennoides, Mullus barbatus, Nephrops norvegicus and Trachurus trachurus.

A strong decrease in the catch of Micromesistius poutassou, Mullus barbatus, Spicara flexuosa, Trachurus trachurus and Octopus vulgaris was evident.

Using the commercial trawler "Nuovo Splendore", a total of 126 hauls were made. One was considered invalid and repeated. The survey took place in seas surrounding Sardinia from 23rd June to 5th August 1997. During this period 31 days were spent fishing and 13 days were for technical breaks.

Unfortunately, SCANMAR equipment was not available, but the duration of hauls was recorded following the recommendations of the Medits protocol.

No technical problems were met with, although often in the shallower waters large quantities of urchins, eel grass (Posidonia oceanica) and algae were encountered and the duration of hauls was slightly decreased. We did not fish many waste products.

During some hauls, especially near the coast where the substratum was irregular and hard, gear was damaged to a certain extent. When damage was not serious some parts of the net were changed; in other cases the reserve net was utilised.

Due to the presence of nets we sometimes modified our course.

Finally, weighing, measuring and maturity evaluation were performed on board, recorded and checked on the computer in the laboratory.

The 1997 Medits survey in the M3 region was carried out from 3^rd June to 6^th July using the professional trawler Sant’Anna. The first sub-zone covered was the Sicilian Strait from 3^rd June to 14^th June 1997. Four people from ITPP were on board. On 16^th June the people from Messina came on board F/V Sant’Anna to cover the part of South Tyrrhenian Sea facing northern Sicily (from Cape Suvero to Cape San Vito) until 22^nd June. On 23^rd 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 6^th.

Hauls performed were 56 in the first sub-zone, 28 in the second and 57 in the third one. The geographical position of two hauls in sub-zone M3a and six hauls in sub-zone M3c was displaced in 1997 survey due to problems regarding the bottom nature.

Before starting the survey, the gear was modified as from Medits protocol and 40 floats were mounted. As regards its maintenance, some damaged parts were substituted both before and during the survey. Finally, some 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.

Both haul registration and processing of biological parameters were accurately performed according to Medits protocol. As in the previous years, the gear operative validity was confirmed at depth below 200 m whereas some doubts still remain for the deeper waters where scarce catches of crustaceans were observed.

The Medits-IT & AL 1997 survey was carried out from 3/06 to 9/08 (68 days, including stand-by and transferring).

The survey lasted 24 days in Ionian areas from Cape Passero to Cape of Otranto (1 transferring day, 2 days of stand-by and 21 working days), 25 days for south-western Adriatic areas from Cape of Otranto to Vieste (1 transferring day, 10 days of stand-by and 14 working days) and 19 days for south-eastern Adriatic areas from S. Johan to Saranda (7 transferring day, 6 days of stand-by and 6 working days).

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

Also this year the trawler "Bianca Maria" was utilized in the whole area; unfortunately, during the survey the relationship between the researchers and the crew wasn’t easy. For this reason it was necessary to recall shipowner (from the co-ordinator of the Unit) to respect the rent contract.

During this survey a larger number of days than 1996 survey was used, because of the bad weather (in July) and the political situation in Albania (we didn’t use the Albanian harbours for standing of the trawler, but at the same time the trawler was forced to continuous transfers from Italy to Albania and vice-versa).

During the 1997 survey the trawler suffered 2 damages: the first about the powerblock, the second about the net entangled in the propeller.

The Medits '97 survey in the northern and central Adriatic sea has been conducted on board the same vessel (Principessa I) both in international waters and in the national waters of each concerned country.

The survey took place between the 2nd and the 22nd of June, at which we must add the extra time to load and unload the fishing material as well as the shipping time at the beginning and the end of the survey.

Scientists from the three concerned laboratories (Split, Ljubliana and Fano) participated in the survey, with in general 4 scientists on board at the same time.

139 hauls have been made on the bases of the same sampling scheme as last year with some new trawling positions. During some hauls, the trawling duration has been reduced due to the presence of rocks on the ground.

The samples have been analysed in the three laboratories, according to their respective area.

The work at sea and in the laboratories has been done in accordance with the "Manuel des protocoles" and the basic data have been sent in due time to the co-ordinator. To calibrate the biological analysis of the samples, exchange of scientists have been made between the three laboratories.

The GR1 operative unit sampled at the North Aegean Sea (North of 38 N), using Kapetan Paraschos, the same commercial trawler as during the 1996 sampling period. The research cruise started at 6 June until 15 July, with 3 days of experimental trawls, 35 days of sea-time, and 8 days of stop. The days of stop were the same as in the previous period of sampling.

The weather conditions extended the survey duration, especially due to the "meltemi", the seasonal strong wind, affected the whole Aegean Sea every summer.

This year the main problem encountered was the presence of many hauled gill-nets, longlines and pots, near the coast and in the open sea. The presence of many small boats through out the North Aegean Sea and hauled gears, induced the boat captain to change slightly the co-ordinates of some hauls, maintained however the same isobath as in previous surveys.

Generally, this year the better knowledge of the trawl particularities and the field characteristics permits better shouting and towed conditions and probably affected the quantities fished.

In total, 63 hauls have been carried out successfully during this cruise. Two of them were repeated twice, due to net sinking into mud. One haul (the 24^th) has been characterized invalid as well as a new one in witch we have stop too early, because the net has been hitched on rocks.

The SCANMAR equipment was not available, but haul’s duration was recorded according to the recommendations (6.1 - Shooting suggestions) of the Medits Trawl Tests in the Adriatic Sea and in Tyrrhenian Sea on 1995 and the results of our experimental hauls.

Three Italian students, Paolo Carpentieri for 17 days, Marta Manca for 9 days and Cristina Milani for 31 days, have taken part in our survey, as part of the ’’Leonardo da Vinci’’ programme.

Weight, measure and maturity of the sampled fish have been carried out on board.

The maturity stage of the species Raja asterias, Raja clavata, Squalus acanthias and Scyliorhinus canicula has not been estimated.

In laboratory data were recorded on computer using the INDMED program and checked using the CHECKMED program.

Abundance indices were calculated for target species only.

The reference list species, which were most abundant in weight this year were in order of magnitude:

E. encrasicolus, S. pilchardus, M. merluccius, A. sphyraena, L. budegassa, M. poutassou, E. cirrhosa, R. clavata, P. longirostris, T. mediterraneus, S. canicula, L. piscatorius, P. blennoides, and I. coindetii. During the 96 survey period the most abundant species were the same, except T. minutus capelanus and L. caudatus.

Considering the number of individuals the most abundant were, in order: E. encrasicolus, A. sphyraena, S. pilchardus, P. longirostris, T. mediterraneus, T. minutus capelanus, T. trachurus, M. poutassou, M. merluccius and during the previous survey: S. pilchardus, E. encrasicolus, M. poutassou, T. minutus capelanus, A. sphyraena, P. longirostris, T. trachurus.

The most wide distributed species were: M. merluccius (59 of 63 hauls), L. budegassa (56 of 63 hauls), E. cirrhosa (46 of 63 hauls), I. coindetii (42 of 63 hauls), S. canicula (39 hauls), P. longirostris (38 hauls), P. blennoides (32 hauls), A. sphyraena (32 hauls), L. boscii (32 hauls), M. poutassou (32 hauls), C. linguatula (32 hauls), T. minutus capelanus (30 hauls), whereas in Medits’96 this order was: M. merluccius (53 of 64 hauls), L. budegassa (47 of 64 hauls), I. coindetii (45 of 64 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).

As we can see, comparing the data of these two years, there exist differences in the relative composition of the catches in weight, in numbers and in the distribution of the various species.

In zone G2, the sampling cruise started on 14/6/97 and ended on 14/8/97. IOANNIS ROSSOS was used, a commercial trawler that has also been used during Medits-GR/94, 95 and 96. Before the beginning of the cruise, the assemblage of the fishing gear was inspected by the national co-ordinator and one delegate of NCMR, in order to assure the observance of the Medits protocol with the new instructions. The functioning of the gear was tested in the N. Evoikos Gulf.

A total of 100 hauls was effected. In the region of Argosaronikos, the good weather conditions helped to carry out a higher number of hauls comparing to the 1996 survey. The functioning of the gear was generally good, however it must be mentioned that the stations which presented hauling problems last year were avoided this year. In the Southern Aegean Sea bad weather conditions and a damage in one of the ship’s winches resulted in the omission of few hauls and to a delay in the completion of the campaign. In the Ionian Sea, some stations were omitted, because of the presence of gill nets and trammel nets set by fishermen. Furthermore, some hauls had a lower duration, because the doors were pinned in the bottom.

As in the previous years during the 1997 sampling period, a SCANMAR system was used by NCMR to observe the following parameters: fishing depth, horizontal and vertical opening of the gear and clearance. The horizontal opening ranged between 13 and 18.8 m, and it showed an increase with depth or warp length. The vertical opening of the gear ranged between 1.9 m in the deepest stations and 3 m in the shallowest stations, but in most stations it ranged between 2.1 and 2.8 m. The contact of the gear with the bottom was generally good down to the depth of 600 m. However, in higher depths it settled down very slowly and it had the performance of a balloon over obstacles.

The hauling speed and 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 consequently of the fish-stock abundance parameters.

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Appendices

Appendix II: Calendar of the survey

Appendix III: Boarding tables

Appendix IV: Stratification scheme

Appendix V: Sampling scheme

Appendix VI: Computer files

Appendix VII: Complements to the survey protocols

Appendix VIII: Update of softwares

Appendix VIX: Meeting reports