IntroductionMorphometric and meristic features are used primarily to study relationships among stocks, such as stock membership, the spatial distribution of stocks, and the phylogeny of stocks (Coyle, 1997;Turan, 2004). According to Begg et al. (1999), phenotypic markers may be more applicable for studying short-term, environmentally induced variation, which is perhaps more applicable for fisheries management. Ibanez-Aguirre et al. ( 2006) also noted that it is of vital importance to identify the study population to understand its dynamics.There are 300 species of pipefishes in 35 genera, and their taxonomy is in urgent need of revision (www. zoonetics.com). The Mediterranean basin has 9 species that belong to the genus Syngnathus (Dawson, 1986); 6 species are distributed in the Black Sea (Bilecenoğlu et al., 2002;Gürkan and Çulha, 2008). Syngnathus acus can be found in coastal and estuarine waters to depths of 90 m or more on sandy, muddy, and rough bottoms; it is relatively common among algal and eelgrass habitats (Dawson, 1986). Pipefishes, like most other syngnathids, are characterized by restricted distributions, low mobility, small home ranges, and low fecundity (Vincent, 1996). Although they have no commercial importance in fisheries, they are threatened by incidental capture in fishing gears and are a common bycatch. This species is not of concern on the IUCN Red List presently, but it is likely to become endangered in the future.Although a few ichthyological studies have focused on pipefish morphometrics (

This study aims to investigate some biological characteristics of Atlantic bonito, Sarda sarda Bloch, 1793, from the Turkish coasts of the Black Sea and the Sea of Marmara. A total of 212 S. sarda (100 females, 89 males, and 23 undetermined) were sampled monthly between May 2011 and September 2012. The sex ratio (♂/♀) was 0.89; females prevailed but not statistically significantly so. Fork lengths of all sampled individuals ranged from 17.7 to 63.0 cm. The length-weight relationship for all individuals was calculated as W = 0.01 L 3.085 . The ages of the fish ranged from 0+ to 2+. Growth parameters calculated according to the von Bertalanffy growth equation were L∞ = 69.565 cm, k = 0.439, t 0 = -1.327 for females; L∞ = 74.603 cm, k = 0.364, t 0 = -1.518 for males; and L∞ = 67.883 cm, k = 0.463, t 0 = -1.220 for both sexes. One hundred ovaries were obtained from the females, and these ovaries were histologically examined to determine the reproductive conditions and developmental stages of oocytes. The gonadosomatic index values calculated for females indicated that spawning generally occurred between May and August. The most intensive spawning period was observed in June and July. The length at first maturity was estimated to be 42.5 cm for females and 36.8 cm for males.

Summary The marbled spinefoot, Siganus rivulatus (Forsskål&Niebuhr, 1775) was recorded for the first time in Izmit Bay, Sea of Marmara. One specimen was caught on 30 September 2019 by a small scale fisherman at depth of 25 m. The fish measured 151 mm in total length and weighted of 43.45 g. S. rivulatus is one of the Lessepsian immigrants who entered the Mediterranean more than half a century ago, and has now also easily adapted to the Sea of Marmara, which has a unique two‐layered water system.

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This study attempted to determine certain characteristics of the species caught in the boat seine fishery in the İstanbul Strait during the 2009-2010 fishing season, including catch composition, commercial and nontarget catch ratios, catch per unit effort (CPUE), and the length distributions of commercial species. A survey of 20 boat seine operations detected species belonging to the following 3 different taxonomic groups: 26 Osteichthyes, 2 Crustacea, and 1 Mollusca. Of all of the nontarget species, 13 were commercial, 14 were noncommercial, and only 1 was under threat. Of the total catch, the proportion of the commercial species in the nontarget catch was 31.3%, and that of the discarded catch, which the fishermen did not take into account, was 2.8%. According to the Spearman rank correlation test, there was a significant correlation between the total catch and the discarded catch (r = 0.759); the size of discarded catch increased as the catch increased (P = 0.000). It was clear from the data that overfishing was seen in the commercial species.