Motor vessel "N. B. Scofield" cruise one of 1953. Cruise Report 53-S-1

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On the diel rhythm of motor activity in perch [Translation from: Informatsionnyi Byulleten Biologiya Vnutrennikh Vod No.30, 12-14, 1976]

The river perch (Perca fluviatilis L.) is most active in the daytime hours, and displays seasonal changes of diel rhythm with a break of the rhythm in spring and autumn. In the present work data were obtained on the motor activity of 3 perch measuring l8-20 cm, caught by net in the littoral of a reservoir and spawned under laboratory conditions. The degree of intensity of movement of perch was judged by special experiments. The results are summarised in this short paper.

Warning signs unheeded in South Pacific invertebrate trade

Nearshore marine resources play a significant role in the lives of South Pacific islanders and can be critical to the economies of nations in the region. However, few countries have adequate management controls in place to ensure harvests remain at sustainable levels, and so determining current levels of utilization is far from easy. A lack of information about the volume of both domestic and international trade in marine invertebrates in high demand is a growing concern. Further hindering management and conservation efforts is the little available background biological information to allow for population assessments, according to this new study on the global trade in South Pacific marine invertebrates.

Motor boat "Constance"

A man on a white motor boat called "Constance" in North West England, UK. This photo is part of a Photo Album that includes pictures from 1935 to 1954.

Gross clinical signs and haematological changes associated with artifical infection of Edwardsiella tarda in Koi Carp

The occurrence of diseases is a significant setback for successful aquafarming. One of the common fish bacterial disease syndromes, Edwardsiellosis is caused by Edwardsiella tarda, a gram-negative, rod shaped bacterium associated with several diseases of marine and fresh water fish. In this study, an attempt was made to observe and analyze the onset of clinical symptoms and certain haematological parameters in Koi Carp, Cyprinus carpio L., following artificial infection with Edwardsiella tarda. The disease progress was observed and the clinical symptoms were monitored over a period of 15 days following infection. Fish were sampled at three day intervals to analyse the haematological parameters: total erythrocyte counts (RBC), total leucocyte counts (WBC), haemoglobin content and differential leucocyte count. Clinical symptoms observed included: erratic swimming behaviour, loss of appetite, haemorrhages, dropsy and exophthalmia. There was a significant decrease in the total RBC and haemoglobin levels by the 3rd and 6th day post infection, and an increase thereafter. WBC counts were higher in all infected groups in comparison to the control group. A significant increase in the number of neutrophils was found in the infected group up to the 9th day and a decrease thereafter. The lymphocyte number was significantly less up to the 12th day while the monocyte counts were significantly higher up to the 12th day post infection. The results showed that the bacterium, E. tarda, is pathogenic to Koi Carp. The hematological changes and clinical signs in infected fish reported in this paper will be helpful in the identification and the control of this infection.