Stock density is one among the most important factors in aquaculture that directly influences the growth of organisms; however, there is limited information about the effects of stocking density on growth performance of sea cucumber Holothuria tubulosa (Gmelin, 1788) that has a commercial potential and represents a new species for aquaculture. In this study, we investigated the effect of stocking densities on the growth performance of juvenile H. tubulosa (40.3 ± 3.34 g) in laboratory conditions. Stocking densities were selected as 6, 15 and 30 ind m⁻² with total biomass 253.3 ± 0.18, 601.2 ± 0.11 and 1201.4 ± 0.15 g m⁻² respectively. We monitored the growth by wet weights and calculated the growth performance through weight gain, growth rate, specific growth rate, relative weight gain, coefficients of variation and survival rate during 8 weeks of research period. We found that individual mean weight gain in 6 ind m⁻² group was approximately 29.53 g while it was 3.03 g and −4.36 g for 15 ind and 30 ind m⁻² groups respectively. Results have shown that the specific growth rate tends to decrease as the number of individuals in unit area increases. The final mean weight, growth rate, specific growth rate, relative weight gain and coefficients of variation were significantly different among treatment groups. In conclusion, a density of 6 ind m⁻² is recommended for stocking juvenile H. tubulosa under rearing conditions. Stocking density of 15 ind m⁻² is not favourable for long term as the growth rate is negligible where 30 ind m⁻² should be avoided in tank-based rearing units.

We assessed the confidence of academics in their careers in fisheries faculties at Turkish universities and developed a scale based on the Job Satisfaction Questionnaire (Cellucci & DeVries, 1978) to classify their attitudes in order to evaluate level of job satisfaction. A survey and a personal information form were made available via the Internet to academics employed in various faculties of fisheries in Turkish universities. Testing for validity and reliability showed that the trust attitudes of academics could be examined with 5 factors: satisfaction with supervisors, satisfaction with coworkers, satisfaction with pay, satisfaction with promotion, and satisfaction with work itself. Results showed that coworkers and promotions were considered more important than the pay. The most important factor in job satisfaction was coworkers, with working as a team and sharing also rated as important. There was no significant difference in the rating of the factors according to gender. These findings are important as preliminary research in the fishing sector.

Objective: The aim of this study was to determine the reproductive cycle and spawning frequency of the sea cucumber Holothuria tubulosa in the northeastern Aegean Sea. Methods: The study covered a period of 12 months, beginning in October 2018 and concluding in September 2019. During this period, sea cucumber samples were collected monthly. Macroscopic and histological examinations of gonadal tubules were conducted to provide credible information for fishery management and aquaculture. Result: The sex ratio of the sampled population was 1:1.3, with 95 males and 130 females. The drained body weights at 50% maturity were 70.90 g for females and 70.80 g for males. The total length at 50% maturity was estimated at 18.58 cm for females and 18.05 cm for males. Gonad maturation was initiated in March and progressed to spawning stages between July and August. From September to February, the gonads were in postspawning and recovery stages. A strong linear correlation was determined between the gonad index and the seawater temperature in the area. Conclusion: The information provided is expected to improve stock management, enforce fishery regulations, and support controlled breeding programs. These measures aim to preserve the natural populations of Holothuria tubulosa and guarantee the long-term viability of the species in the wild. Abstract Impact statement The Holothuria tubulosa is the most abundant commercial sea cucumber species found in the Mediterranean Sea, particularly in the Aegean Sea. This species plays an important ecological role in nutrient regeneration and surface sediment mineralization in the benthic zone; however, there is significant catch pressure on natural stocks. This study revealed the reproductive cycle of this Mediterranean Sea cucumber species, offering crucial data for sustainable fisheries and aquaculture. By understanding their breeding patterns, we can better manage wild populations and develop controlled breeding programs, ensuring the long-term survival of the species and supporting healthy marine ecosystems.

The Mediterranean sea cucumbers including Holothuria polii has become commercially important in international trade due to the high demand of consumers from Far East countries. Sea cucumbers fisheries is a valuable income for the regional fishermen but natural stocks endangered by overfishing in recent years. Fisheries regulations and aquaculture studies are important precautions for preserving natural stocks. All these efforts are based on reproduction biology of this species which slightly differed among regions. In this study, the reproduction biology including morphological characteristics, gonadosomatic index and gonadal development stages of H.polii at the eastern coast of Aegean Sea (Izmir, Turkey) were investigated during the reproduction (spawning) period from July to October 2018. Gonads and gonad sections of 60 sea cucumbers (120.60 ± 19.56 g) have been observed by macroscopic and microscopic inspections. Three gonadal development stages have been identified by histologic observations as mature (III), spawning (IV) and post-spawning stage (V) in gonadal tubules. Results indicate that both female and male gonads are at mature and spawning stage in July and all gonads are at post-spawning stage in October. The mean gonad weight was 12.53 ± 1.33 g at the beginning of the spawning period (July) and 1.87 ± 0.58 g at the end of the spawning period (October). Gonadosomatic index decreased from 17.53 ± 0.02% (July) to 3.37 ± 0.01% (October) after spawning. The gonadosomatic index, gonad weight, and spawning were related to the seawater temperature. According to this study, the spawning period of H.polii at the eastern coasts of the Aegean Sea starts in July and completely ends in October. As a result, the data related to the reproduction biology in spawning period of H.polii would guide stock management and artificial breeding of this species under controlled conditions.

Bu çalışmada Türkiye’nin de içinde olduğu 16 Orta Doğu ülkesinin bugünkü ve gelecekteki iç su ürünleri avcılık ve yetiştiricilik üretimi, istatistik verileri yardımıyla değerlendirilmiştir. Trend analizi sonucunda 2015 yılında yaklaşık 390 000 ton olan Orta Doğu iç su avcılık üretiminin 2020 yılında 380 000 tona gerileyebileceği, 2015 yılında 1 660 000 ton olan yetiştiricilik üretiminin 2020 yılında yaklaşık 2 060 000 ton olabileceği tahmin edilmiştir. Türkiye’de ise toplam su ürünleri üretiminin 2016 yılı itibariyle %5,8 ‘ini oluşturan iç su ürünleri avcılığının 2020 yılında daha da azalacağı (30 000 ton), %17,2’sini oluşturan iç su ürünleri yetiştiriciliğinin ise artmaya devam edeceği (133 000 ton) öngörülmüştür. İç su ürünleri balıkçılığının sürdürülebilir olması ve sektörün gelişimi protein talebinin karşılanması ve sosyo-ekonomik gelişim açısından önemlidir.