Malik H. Ali

The reproductive biology of Parhyale basrensis Salman (Crustacea, Amphipoda) in the Shatt al-Arab river

Basic biological investigations on the intertidal amphipod Parhyale basrensis are made. The incubation period is 1–2 weeks. The generation time is 5–6 weeks. Females produce at least 4 broods before they die. The number of eggs carried by the female is a linear function of size of the female. Egg numbers varies from 4–37. Maturity occurs at a size of 4 mm for the female and 4·5 mm for the male. The breeding season is extending from late February to late November or December. Recruitment starts at the beginning of May. Successive broods may have different life spans. The maximum life span of the population is 13–15 months and the minimum life span is 6–7 months.

Abundance and seasonal migrations of the penaeid shrimp Metapenaeus affinis (H. Milne-Edwards) within Iraqi waters

Migration of Metapenaeus affinis (H. Milne-Edwards) from the Arabian Gulf to nursery grounds in the inland waters of Iraq extends from May/June to January/February. Shrimp ranging in size from 3–125 mm total length were found in inland waters. In the shallow waters of the Al-Assaflya small-sized shrimp only were caught, while in the Marshes large-sized shrimp were abundant. Maximum numbers of recruits were recorded when temperatures reached 23–25 °C. However, the discharge of the Shatt Al-Arab may also be an important factor regulating recruitment.The growth rates of small shrimp were higher than those of large ones. There mostly was, a preponderance of females over males. Spawning at sea appears to occur immediately after emigration. Gonad development was not observed. Commercial landings, at the two main fish markets at Basrah, during September–November 1985 averaged 1000 kg day−1.

Life cycle and population dynamics of Annina mesopotamica (Ahmed), (Isopoda, Flabellifera) in the Shatt Al-Arab Region, Basrah, Iraq

A population of the intertidal, ovoviviparous, cirolanid isopod Annina mesopotamica was studied at the Al-Chibassy tributary of the Shatt Al-Arab river from 14 May 1973 to 29 April 1974, and at the Garmat-Ali river of the Shatt Al-Arab, Basrah, Iraq from 5 November 1984 to 30 June 1986. Population density varied between 128 to 5760 individuals m−2 with a mean of 1218 m−2. Highest numbers occurred between June and September. Breeding extended for most of the year except November/January to February/March, although ovigerous females were present throughout the year. The incubation period varied with season, and was ca. 2 weeks during the warmest period, and about a month at lower temperatures. Egg numbers varied between 4 to 66 with mean 24. Brood size was linearly proportional to female size. The size frequency distribution of the population was polymodal with a predominance of females over males. Four different types of growth curves were found: exponential, concave, convex, and intermediate between concave and convex. Growth rate varied between 0.63 and 2.19 mm month−1. Mortality was higher among summer cohorts. Life span varied between 5 and 11 months.