Effects of depth and season on catch volume of bottom gillnets employed along the Fatsa coasts of the South-eastern Black Sea

• Main Author: İsmet Balik
• Format: Article
• Language: English
• Published: Ege University 2020-06-01
• Series: Su Ürünleri Dergisi
• Subjects: black sea; depth; season; catch per unit effort; gillnet fishery
• Online Access: https://dergipark.org.tr/tr/pub/egejfas/issue/50158/633269

The study was conducted along the Fatsa coasts of the South-eastern Black Sea, to investigate the effects of depth and season on catch volume of the bottom gillnet fishery. During the study, fishing was carried out using multifilament gillnets with mesh sizes of 32, 34, 36 and 38 mm in each of the four different depth strata (0-14 m, 15-29 m, 30-49 m and ≥50 m) three times per month between March 2013 and February 2014 (except for July and August), with a total of 30 gillnet hauls performed. The results of the study revealed that in all seasons whiting (Merlangius merlangus) was caught most in the 30 m and deeper water layers. However, whiting catch increased with increasing water depth. Most red mullets (Mullus barbatus) were caught in the 0-14 m depth waters during spring, winter and autumn periods, while its catch was the greatest in the 15-29 m during the summer period. Catch of this species decreased gradually with increasing water depth. Another fish species was pontic shad (Alosa immaculata) which was caught least in the shallow waters. However, during all seasons its catch increased gradually with increasing water depth up to the 30-49 m depth strata. Nevertheless, it was determined that catch volume for this species decreased in the ≥50 m level again. On the other hand, Mediterranean horse mackerel (Trachurus mediterraneus) was mostly caught in the shallow waters (0-14 m and 15-29 m) during all seasons. Especially in the ≥50 m waters, no Mediterranean horse mackerel was sampled during the study. This study presents that amounts of catch for the fish species sampled were affected especially by water depth and seasons.