Keban Baraj Gölü, A¤›n Yöresi Tatl› Su ‹stakozu, Astacus leptodactylus Eschscholtz Populasyonunda A¤›rl›k-Uzunluk ‹liflkisi ve Et Verimi
Keban Baraj Gölü, A¤›n Yöresi tatl› su istakozu, Astacus leptodactylus Eschscholtz populasyonunda a¤›rl›k-uzunluk iliflkisi ve et verimi incelendi. Erkek ve difli kerevitlerde karapaks uzunlu¤u ile vücut a¤›rl›¤› aras›nda do¤rusal bir iliflkinin oldu¤u saptand› (r2 erkekler= 0.923 ve r2 difliler= 0.882). Bununla birlikte, regresyon analizlerinden elde edilen e¤imler hem erkek hem de difli kerevitlerde negatif allometrik a¤›rl›k art›fl›n›n oldu¤unu gösterdi (e¤imerkekler= 2,66 ve e¤imdifliler= 2,51). Ayn› boy grubundaki (46-58 mm karapaks) diflilerin erkeklere göre abdomenlerinin istatistiksel olarak önemli derecede genifl oldu¤u (P <0,001), erkeklerin ise diflilere göre k›skaç geniflli¤inin ve uzunlu¤unun, ayr›ca k›skaç aya¤›n›n önemli derecede uzun oldu¤u saptand› (P <0,001 her bir durum için). Erkek ve difli kerevitlerin abdomenlerinden elde edilen et verimi aras›ndaki fark istatistiksel olarak önemli olmamas›na ra¤men (P >0,05), erkeklerin k›skaç›ndan elde edilen et verimi ve toplam et verimi diflilerinkinden önemli derecede yüksek bulundu (P <0,001 her bir durum için). Ayr›ca, yap›lan bu çal›flmada hem erkek hem de diflilerde abdomen etinin negatif allometrik büyüme göstermesi, kerevit çiftliklerinde kerevitin bir süre daha semirtilmesi veya pazara sunulmas›n›n belirlenmesinde bu durumun göz önünde tutulmas›n›n gere¤ini ortaya koymaktad›r.
The Relationships between Length-Weight, and Meat Yield of Freshwater Crayfish, Astacus leptodactylus Eschscholtz, in the Ağın Region of Keban Dam Lake
The relationships between length-weight, and meat yield of freshwater crayfish, Astacus leptodactylus, in the A¤›n Region of Keban Dam Lake, were investigated. In both sexes a linear relation was found between carapace length and wet body weight (r2 males= 0.923 and r2 females= 0.882). In addition, regression coefficients (slopes) showed that negative allometric body weight increase occurs in both sexes (slope males= 2.66 and slope females = 2.51). For a certain size range (46-58 mm carapace), the abdomen width of females was found to be significantly larger (P <0.001) than that of males. However, the chelae width, chelae length and cheliped length of males were found to be significantly larger and longer (P <0.001 for each case) than those of females. Although there was not a significant difference in the abdomen meat yield between males and females (P >0.05), there was a significant difference in the chelae and total meat yield between males and females (P <0.001 for each case) in favour of the former. In the present study, it was also observed that negative allometric growth occurs in the abdomen meat of both sexes which should be considered in the determination of harvesting time in the management of crayfish farms.
