S. Nikolaev, V. Maximov, E. Anton, INCDM( National Institute for Marine Research and Development) “Grigore Antipa” Constanta PRELIMINARY RESEARCH INTO OPPORTUNITIES FOR FISHING CHAMELEA GALLINA (VENUS GALLINA) ALONG THE ROMANIAN BLACK SEA COAST BY USING HYDRAULIC DREDGES S. Nikolaev, V. Maximov, E. Anton, G. Tiganov, A. Filimon

Experiments were conducted in order to establish the prevalence and density of the clam population, the functioning of the hydraulic dredge and the expected effects from its use on the sea water environment and habitats and the population of bottom-dwelling species. They were conducted with the assistance provided by the company S.C. ROMFISH MARINA SRL, Constanta (J13/2867/2011, UIC 200948741, manager Binali TARAKCI) under a Collaboration agreement No. 836 (6) / 26.02.2015 (pursuant to Art. 3 thereof). Observations were made upon receiving an Order for expedition No. 5036/22.11.2017 onboard the Romfish 1 ship on 23.11.2016 in the presence of specialists from INCDM in the following areas: Baia Mamaia and Agigea – Eforie Nord.   Dredge 1 Baia Mamaia H = 16 m Dredge 2 Baia Mamaia H = 18 m Dredge 3E Eforie kg/m2 44º14’74’’ 28º41’35’’ 44º14’44’’ 28º41’’91’’ 44º14’41’’ 28º41’’46’’ Chamelea gallina 0.139 0.185 1.23

A hydraulic dredge is a classical dredge, which has been further equipped with a system of orifices (nozzles) to direct water jets under pressure (the pressure of the water jet is 2–3 bars) mounted at the front. The body of the dredge consists of a rectangular metal frame covered with a net or a grid structure with apertures of 10-12 mm inbetween bars. The frontal part of the dredge is equipped with a catch mechanism which retrieves into the dredge any organisms picked up by the water jet.

The quantity of biomass from clam deposits (Chamelea gallina) or other mollusc species inhabiting the Black Sea coastal area has not been calculated so far. Specialists from INCDM Grigore Antipa onboard the Romfish 1 ship conducted measurements during clam harvesting which are, however, not considered indicative as measurements were taken within a single day and within a limited scope (Baia Mamaia – Eforie Nord), a single area which comprises a small part of the Romanian coastal area. Taking into consideration the short growth cycle of Chamelea gallina clams which determines their reproduction rates, it is reasonable to expect large variations in the number of clams deposited on the bottom during the second year of their life as well as in their productivity and it is therefore necessary to conduct larger research into clam populations (to be conducted every year), encompassing the annual growth cycle of the species. 

Since during the expedition weather conditions were unfavourable and did not allow investigation into the effects of the hydraulic dredge on the marine environment, the relevant descriptions were made entirely based on specialised literature, and it is therefore necessary to continue observations until this aspect has been thoroughly analysed. In view of the above, we believe that the direct observations and research activities in the examined areas must continue applying direct and indirect methods of observation (ROV, side scanning, cameras, etc.), during the entire 2018.  

A hydraulic dredge, by lifting with the jet the superficial layer of the sea bottom, creates additional underwater currents in the surrounding environment which in turn draws in the fine sediments (particles containing minerals as well as organic and toxic substances deposited on the bottom of the sea). Another aspect which needs to be clarified is their impact on protected marine areas (Order No. 46/2016 on establishing а scheme for the protection of natural territories and on declaring areas of European significance as part of the European environmental network Natura 2000 on Romanian territory), located in immediate proximity to areas where clam resources are being exploited in the southern part of the Romanian coast.

In view of the above, we have attempted to form an argumented opinion when determining the recommended TAC rates (Total Allowable Catch) on the advisability of the use of hydraulic dredges and we believe that it is necessary for the following conditions to be met: - Developing a national programme for calculating exploitable marine mollusc resources (including the clam species in question); - Conducting experimental research on the impact from the use of hydraulic dredges on bottom biocoenosis by applying direct observation technology; - Budgeting and securing the funds required for these activities.

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In order to more successfully solve the issues raised above, we believe that it is necessary to clarify some legal aspects in view of the fact that pursuant to Order No. 449/2008 on the technical characteristics and exploitation conditions for the permitted commercial fishing methods and equipment in marine and continental water basins: - dredges are not included in the lists of permitted fishing equipment in Romanian waters; - the use of dredging equipment is forbidden below the 20 m isobathic line. I, the undersigned Petar Galabov hereby certify that my translation from Bulgarian into English of this text from a specialised presentation the field of marine fishing distributed into 9 slides is true and correct. Signature: Galabov