No abstract

Female Rhizoprionodon acutus were found to mature between 62 and 74 cm total length (L T ) whereas males matured between 63 and 71 cm L T . The L T at 50% maturity was 64Á3 cm for females and 64Á7 cm for males. Litter size varied from one to six embryos, and was positively correlated with maternal L T . Female embryos outnumbered males by a ratio of 2Á3:1. The size at birth was c. 37 cm L T . Full-term embryos and post-partum females were observed during all seasons although their occurrence was highest in spring. Spermatozoa were rarely recorded in the oviducal gland, indicating that this species does not store sperm. It was not possible to generate maturity curves for Iago omanensis but it was evident that females matured by the time they reached 35 cm and males were mature by 31 cm L T . This species displayed a clearly defined reproductive cycle with parturition occurring primarily in spring, after a gestation period of c. 1 year. Maximal embryo size was 19 cm L T while maximal litter size was 24 embryos. The oviducal gland appeared to act as a seminal receptacle and it appeared that females may utilize these stores by not mating every year.

The spawning periods, sex ratio and length at first maturity were determined for six commercially important finfish species collected from Oman's industrial trawl fishery. During 1 year of monthly sampling, biological data were collected on 5586 fish. ANCOVA ANCOVA was used to compare the length-weight relationships between sexes. There were sex-specific differences in length-weight relationships for three of the six species examined. One serranid, Epinephelus diacanthus, and a sparid, Pagellus affinis, had sex ratios significantly different from the expected ratio of 1 : 1. Size-frequency data revealed more male fish in the larger size classes for E. diacanthus, P. affinis and Nemipterus japonicus. Data on the development of female gonads and Gonado-somatic Index (GSI) revealed that the six species spawned at different times of the year. With the exception of female E. diacanthus, all fish had low GSI values during the onset of the summer monsoon period in June. The proportion of immature vs mature fish in the sample differed among species. For two species, Lethrinus nebulosus and Cheimerius nufar, more than 40% of the fish sampled (both sexes) were immature. Approximately 33% female and 41% male P. affinis were also immature. Management options such as temporal and area closures are discussed in light of the large number of immature fish caught by the fishery.

In an attempt to initiate seafood biotechnology in the Sultanate of Oman, Middle East, using underutilized fish, fish burgers from two different formulas were developed and the quality and storage stability were evaluated during storage at -20∞C for 3 months. Quality and storage stability were evaluated through total aerobic and coliform bacterial count, peroxide value, protein solubility, and color. Total aerobic bacteria were reduced significantly (P < 0.05) by 84% and 97% of the initial load in formulas 1 and 2, respectively, whereas coliforms were completely destroyed in both formulas at the end of storage. Peroxide value increased (P < 0.05) but did not reach detectable levels of rancidity. Salt-soluble protein content decreased remarkably during the storage period. The L value showed good stability during storage, keeping products bright for 3 months. Fish burgers from both formulas were acceptable for 3 months at -20∞C. Storage stability was rationalized by the effectiveness of freezing, and antimicrobial and antioxidant properties of food additives.KEY WORDS: aerobic bacteria, coliforms, fish burger, peroxide value, quality, storage stability.

No abstract