An evaluation of the performance of artificial networks (ANNs) to estimate the weights of blue crab (Callinectes sapidus) catches in Yumurtalık Cove (Iskenderun Bay) that uses measured predictor variables is presented, including carapace width (CW), sex (male, female and female with eggs), and sampling month. Blue crabs (n=410) were collected each month between 15 September 1996 and 15 May 1998. Sex, CW, and sampling month were used and specified in the input layer of the network. The weights of the blue crabs were utilized in the output layer of the network. A multi-layer perception architecture model was used and was calibrated with the Levenberg Marguardt (LM) algorithm. Finally, the values were determined by the ANN model using the actual data. The mean square error (MSE) was measured as 3.3, and the best results had a correlation coefficient (R) of 0.93. We compared the predictive capacity of the general linear model (GLM) versus the Artificial Neural Network model (ANN) for the estimation of the weights of blue crabs from independent field data. The results indicated the higher performance capacity of the ANN to predict weights compared to the GLM (R=0.97 vs. R=0.95, raw variable) when evaluated against independent field data.

Abstract:The blue crab (Callinectes sapidus) is native to the western Atlantic, but is an invasive species in the Mediterranean. This study examined the dynamics of growth in an invasive population of blue crab in the Yumurtalık Cove, Turkey (North Eastern Mediterranean). Growth was quantified using a discontinuous growth model, a molt process model. Crab growth histories were observed for individual crabs held in field enclosures in summer 2010 and 2011. Carapace widths ranged from 14.13 to 80.07 mm. A mean growth per molt of 120.6% increase in carapace width was observed. Chronological inter-molt periods ranging between 3 days and 67 days were observed. The average IMP was 16 days in Yumurtalık Cove. The mean physiological IMP was 270±163 degree-days, ranging from 72-781 degree-days.

Özet: Bu çalışma ile 2002-2003 tarihleri arasında elde edilen örnekler incelenerek Mürekkep balığı Sepia officinalis (L.)'nin morfometrik özellikleri ve üreme biyolojisi (gonadosomatik indeks) özellikleri belirlenmiştir. Karataş kıyılarında (Kuzeydoğu Akdeniz), ticari balıkçı teknesiyle toplam 22 trol çekimleri yapılmıştır. Örneklemeler 20-120 m derinlikler arasında gerçekleştirilmiştir. Toplam 217 dişi, 399 erkek ve 289 cinsiyeti tanımlanamayan olmak üzere toplam 905 birey incelenmiştir. Erkek, dişi ve belirlenemeyen bireylerde, sırasıyla ortalama manto boyu 98.36 ±0.84 mm, 105.88 ±1.19 mm ve 61.89 ±1.02 mm ölçülmüştür. Manto boyu ile total boy ve kabuk boyu arasında doğrusal ilişki bulunurken, ağırlık ile üssel bir ilişki saptanmıştır. Populasyonda dişi/erkek oranı (D:E) 0,54:1 şeklinde bulunmuştur. Dişilerde olgun (IV, V) evredeki bireyler ocak ayından nisan ayına kadar görülürken, ilk gelişme evresindeki bireylere haziran ayından itibaren rastlanmıştır. Eşeylere ait Gonadosomatik İndeks (GSİ) değerlerinin yıl içindeki aylık değişimleri incelendiğinde yumurtlamanın Karataş kıyılarında nisan ayında başladığı ve eylül ayına kadar devam ettiği görülmektedir. Anahtar Kelimeler: Mürekkep Balığı, Sepia officinalis, Karataş açıkları (Kuzeydoğu Akdeniz), Morfometrik Özellikler, Üreme Biyolojisi Bu çalışma Ç.Ü. SÜF2002BAP20 no'lu proje tarafından desteklenmiştir. Journal of FisheriesSciences.com Türeli Bilen ve ark., 4(4): 400-411 (2010)Journal abbreviation: J FisheriesSciences.com 401 Abstract: Some biological aspects of cuttlebone (Sepia officinalis L., 1758) of the coastal area of Karataş (Northeastern Mediterranean-Turkey) This study was investigated morphometric aspects, reproductive biology (gonadosomatik index), of cuttlefish Sepia officinalis (L.) from September 2002 to September 2003. Samples collected in 22 trawl surveys from commercial vessels on Karataş coasts. The trawl surveys carried out at depths from 20 to 120 m. It investigated that total 217 females, 399 males, and 289 indeterminate individuals. The mean mantle lengths of males, females, and indeterminate individuals were 98.36 ±0.84 mm, 105.88 ±1.19 mm, and 61.89 ±1.02 mm respectively. The relationships between mantle length and the total length are linear. The MB: W relationships are isometric. The population of mature males were dominant to females (sex ratio=0,54:1). Female individuals with ripe gonads (IV,V) were dominant from January until April, and females with pre-mature gonads (I) showed in June. It showed that spawned occurred between April and September in off coastal area of Karataş.Figure 5. The relationship between mantle length and weight graphs (a) male (b) female (c) undefined Journal of FisheriesSciences.com Türeli Bilen ve ark., 4(4): 400-411 (2010) Journal abbreviation: J FisheriesSciences.com