At the request of the Director of Trabzon Fisheries Research Institute, the following list of research work which could usefully be done by the Institute in preparation for the proposed programme of Black Sea seatrout and sturgeon enhancement was prepared:
Water quality parameters: The following water quality parameters are of importance for fish hatchery supplies: temperature, pH, dissolved oxygen concentration, conductivity, turbidity. It will be useful to measure these at the locations selected as possible seatrout hatchery sites on the Çaglayan, Kapistre, Findikli, Firtina, and Baltaci Rivers. At the Firtina site, measurements should be taken from both the main river and spring-fed side branch which enters the river at Senyuva school. The flow rate of this stream should also be estimated. For comparison, the same parameters could be measured at convenient points near the coastal road on the Solakli, Iyidere and Taşlidere Rivers. It will probably not be possible to take samples more than once a month, in combination with the Institute's routine pollution monitoring work.
Sampling of juvenile seatrout in the major rivers can be done using the electro-fishing apparatus purchased for project TCP/TUR/8853. Fishing should be concentrated in spring (May-June) with a view to capturing downstream-migrating smolts. Fish should be measured, scale samples be taken, and fish returned to the water unharmed. Age of smolts can then be determined by scale-reading. To determine age and size at smoltification, it is necessary only to capture a maximum of 10–20 fish.
Catch data and determination of age and size at maturation: Collection of data from fishermen's cooperatives and individual fishermen, already started, should be continued. Scale-reading will confirm age at sexual maturation for males and females, and growth rate in the sea will be determined from fish weight and length data. Information on place and data of capture will help determine the most important rivers for reproduction, and route and timing of the spawning migration.
7.2 STURGEONS
Water quality parameters: The same water quality parameters listed above for seatrout hatchery sites could also be usefully measured at the proposed sturgeon hatchery site on the Yeşilirmak River. In addition, total gas saturation should be measured. The measurements must be taken above the dam (in the reservoir) from the point where the hatchery will draw its water, i.e., close to the dam wall. Samples should be taken from various depths - from the surface and at 5-m intervals to the bottom, and a record of the water depth behind the dam made at the same time.
Sampling of sturgeon broodstock: Broodfish entering the Kizilirmak and Yeşilirmak rivermouths could be sampled, their species, size, sex and stage of maturation determined in vivo, then be returned undamaged to the water. However, specialist knowledge of techniques for live fish handling, extraction of eggs, and examination of the eggs' stage of maturation is needed before this work can be attempted, otherwise the only result is likely to be the killing of sturgeon broodfish. It is therefore suggested that this work should only be attempted if the fellowship candidate in sturgeon reproduction has learned the necessary procedures overseas.
Trial induction of ovulation: Similarly, this cannot be attempted until staff have received training. If expertise and facilities are available, however, a trial induction of ovulation and spermiation in broodfish held in a hatchery or aquarium could be undertaken.
