Selenium-Mercury Balance in Commercial Fish Species from the Turkish Waters

Biological Trace Element Research - The interactions between selenium (Se) and mercury (Hg) were assessed in order to interpret public health risk, associated with dietary mercury exposure due to...     

Hook selectivity and catch efficiency in two sport fishing sectors in the Strait of Istanbul,Turkey: Classic handline fishing and Light Rock Fishing (LRF)

In this study, the efficiency of two fishing methods (a) traditional handline commonly used in the Strait of Istanbul and (b) light rock fishing (LRF), which is beginning to spread in recent years, were investigated by monthly sampling between September 2014 and September 2015. One classic handline fishing tackle and one LRF fishing tackle were used in the test fishing exercise. In addition, the effects of the hook sizes (numbers 6, 8 and 10) used in the handline fishery on the size selectivity for horse mackerels were also studied. Catches using both types of fishing gear were mainly composed of Trachurus mediterraneus (89.60%), Scorpeana porcus (5.12%), Sardina pilchardus (1.98%), Atherina boyeri (0.99%), Liza aurata (0.66%), Scorpaena scrofa (0.50%), Pomatomus saltatrix (0.33%), Sprattus sprattus (0.33%) and a few other species. The frequency distributions of horse mackerel caught using handlines and LRF were slightly different and ranged between 6.1–19.0 cm and 9.0–16.0 cm, respectively. Of all the handlines, LRF yielded the highest catch per unit effort (CPUE), 1.295 kg/10 hooks/hour. The log normal model selectivity curve gave the best fit for the T. mediterraneus by using the SELECT method. The modal lengths of horse mackerel caught by handline hook sizes no.10 and no. 8 hook were calculated as 13.4 cm and 17.7 cm, respectively. In addition, the spread values were determined with 3.58 and 4.74, respectively.     

Untersuchungen über die dynamogene Funktion der Antennen bei Anacridium aegyptium

Zusammenfassung Bei Imagines von Anacridium aegyptium wird nach unilateraler und bilateraler Entfernung der Antennen die Klettergeschwindigkeit, die Lokomotionsgeschwindigkeit bei positiver Phototaxis und die Fluggeschwindigkeit herabgesetzt. Beidseitige Entfernung der Antennen setzt diese Geschwindigkeit stärker herab als einseitige. Die Antennen spielen also ähnlich wie die Ocellen eine stimulierende (dynamogene) Rolle.

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Summary Following the removal of a single antenna of imaginal Anacridium aegyptium the speed of positive phototactic movements, of climbing and of flying is reduced. Bilateral removal of the antennae results in further reduction of these speeds. Thus, similar to the ocelli, the antennae also have a stimulating (dynamogenic) function.

     

First record of the Lessepsian fish Siganus rivulatus (Forsskål & Niebuhr, 1775) in the Sea of Marmara (Izmit Bay,Turkey)

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.