The water temperature at the two sites demonstrated a clear seasonal variation between the winter minimum (18.1 °C) in February and the summer maximum (29.1 °C) in July (Figure 2). The pH ranged from 7.85 to 8.60 at Abu-Qir and from 8.10 to 9.00 at El-Mex. Salinity displayed a narrow variation (38.4–39.9‰) at Abu-Qir, in contrast to the wide variation (24.4–39.8%) at El-Mex (Figure 3), which receives a large volume of waste water from El-Umoum Drain. DO was high (7.1–10 mg l− 1) at Abu-Qir selleck compound but varied widely at El-Mex, between 4.4 and 14.6 mg l− 1. BOD was lower at the stressed site (El-Mex) (1.1–5.7 mg l− 1) than at Abu-Qir

(3.3–7.4 mg l− 1). During the study period the biometric measurements and reproductive examination were carried out on a total of 447 and 822 specimens of Pseudonereis anomala from Abu Qir and El Mex respectively. The monthly number of worms examined depended upon their monthly abundance at each site and is given in Figure 4. A high percentage of the worms from Abu Qir (46.2%) were from > 2 to 4 cm long, and a significant proportion (35%) were between > 4 and 6 cm long. Both length ranges were dominant at El Mex but in the reverse order: 31.7% were > 2–4 cm long Dasatinib cost and 42.9% had a length of > 4–6 cm.

On the other hand, shorter individuals (< 2 cm) made a greater contribution to the Abu Qir population (5.9%) than to the El Mex population (1.9%), while longer ones (> 6–12 cm) were less prevalent (13.5%) at Abu Qir than at El Mex (23.5%). The respective lengths of the shortest worms were very similar (1.1 and 1 cm) in both areas, occurring during autumn (September and October respectively). Meanwhile, the longest individuals in the two areas were females, attaining a greater length (11.9 cm)

at El Mex in February, against 9.8 cm at Abu Qir in both June and July. On a monthly scale, the length range of > 2–4 cm prevailed over the > 4–6 cm selleck kinase inhibitor length range during a significant part of the year at Abu Qir, whereas both ranges made similar contributions during the rest of the year (Figure 4). At El Mex, the range of > 4–6 cm prevailed for most of the year, whereas higher percentages of the > 2–4 cm range were recorded during only 4 months (Figure 5). The minimum biomass (0.004 g) was the same at both sites in September, but the maximum biomass (0.768 g) at Abu Qir was recorded in both June and July and was markedly smaller than that (1.303 g) at El Mex in February. The majority of the Abu Qir worms (79%) weighted ≤ 0.2 g against 65% at El Mex, but the proportions of the greater weight classes (> 0.2–0.4 g and > 0.4–0.8 g) were lower at Abu Qir (17% and 4% respectively) than at El Mex (22.3% and 10.6% respectively). Meanwhile, worms weighing > 0.8 g made up 2.1% of the El Mex population, but were wholly lacking at Abu Qir.