A Single-armed Manta-board as a New Diver-controlled Planing Board and Its Use for Underwater Surveys

Due to inadequacies of previous underwater towing techniques and the special needs of a recent underwater survey, a modified mania-board technique was developed. With this new technique, the diver holds on to the manta-board with one arm; consequently, the board is referred to as a single-armed manta-board (sam-board). The sam-board proved inexpensive and highly maneuverable, allowing the divers to freely collect samples or record information. Through some experimenting with the board and changing some of the variables, such as rope lengths, towing speeds, etc., a highly efficient towing method can be achieved. Preplanning and strict diving safety procedures must, however, be implemented to assure efficiency. This paper presents the materials, guidelines for board construction, equipment, and preplanning and diving safety procedures necessary for the sam-board towing operation.

Social Organisation of the Short-finned Pilot Whale, Globicephala macrorhynchus, with Special Reference to the Comparative Social Ecology of Delphinids

As a contribution to the understanding of comparative social trends within the cetacean family Delphinidae, a 22-month study was conducted on the shortfinned pilot whale, Globicephala macrorhynchus, which has been suggested to have a unique social system in which males and females in the same group are related and mating occurs outside of the group. The individual identification of 495 pilot whales, analysed in daily group association patterns, allowed identification of 46 pods. They were classified as productive or non-productive based on the presence or absence of immature animals. Productive pods were a significantly larger, although 12% of them lacked adult males. Two classes of whales (residents and visitors) were defined by patterns of occurrence,suggesting differential patterns of habitat use. Resident pods occasionally travelled together (41% of all groups) and associations between age and sex classes showed that in mixed-pod groups, the highest ranked associations of the reproductive females were with males from other pods, while within pods, adult males and females associated less. During summer, the proposed peak conception period, pilot whale groups were significantly larger and contained individuals from a significantly greater number of pods. These findings support the hypothesis that males and females mate when associating with individuals from other pods. A comparative analysis of sexual dimorphism, brain size, and testes size, habitat, prey and group size within the 17 delphinid genera identified a correlation between sexual dimorphism and body size, but relative measures of brain size and testes size did not correlate with broad ecological or social classifications. However, a comparison of three delphinid societies identified two distinct male mating systems: males of the small, mono-morphic Tursiops truncatus live in age/sex segregated groups and mate with a number of discrete female communities. Males in the large sexually dimorphic Glob icephala spp. and Orcinus orca mate with associated female pods and yet remain with their female kin. This corresponds to the avunculate social system described in some human societies. It could evolve from a promiscuous mating system where there is little guarantee of paternity and where males that live with their kin increase their inclusive fitness.

Recent progress in the identification and determination of freshwater phytoplankton in the natural environment

The biomass of the phytoplankton and its composition is one of the most important factors in water quality control. Determination of the phytoplankton assemblage is usually done by microscopic analysis (Utermöhl's method). Quantitative estimations of the biovolume, by cell counting and cell size measurements, are time-consuming and normally are not done in routine water quality control. Several alternatives have been tried: computer-based image analysis, spectral fluorescence signatures, flow cytometry and pigment fingerprinting aided by high performance liquid chromatography (HPLC). The latter method is based on the fact that each major algal group of taxa contains a specific carotenoid which can be used for identification and relative quantification of the taxa in the total assemblage. This article gives a brief comparative introduction to the different techniques available and presents some recent results obtained by HPLC-based pigment fingerprinting, applied to three lakes of different trophic status. The results show that this technique yields reliable results from different lake types and is a powerful tool for studying the distribution pattern of the phytoplankton community in relation to water depth. However, some restrictions should be taken into account for the interpretation of routine data.

The riverine fisheries of large sized siluroids with special reference to Aorichthys seenghala (Sykes)

The significance of large siluroids in dynamics of riverine fish catch composition pinpointed the need to appraise that i) fisheries; ii) status in riverine fisheries; and iii) factors influencing their fisheries with special reference to Aorichthys seenghala (Sykes). The investigations were carried out in the middle stretch of Ganga river system around Allahabad. The study concluded that although, catch of large siluroids had declined but their share in riverine catch increased. The same was true for A. seenghala. The increase in fishing intensity in A. seenghala breeding grounds was one of the evident indicators of fishing stress on the fish. Strong seasonality was observed in its catch over the year. The wanton killing of breeding population during premonsoon and juveniles during postmonsoon may be attributed for this seasonality and decline in its catch. The fishing stress needs to be diverted through some more lucrative option to save its fisheries. Collection of young ones from the nest, during breeding months and their subsequent culture may be one of the conservation measures. It would also generate additional employment for fishers and defer wanton killing of brood stock.

Identification and effectiveness of self-help groups in Cambodia

The CGIAR Research Program on Aquatic Agricultural Systems (AAS) seeks to reduce poverty and improve food security for the millions of small-scale fishers and farmers who depend on the world’s floodplains, deltas and coasts. AAS combines more conventional approaches for introducing and scaling technical innovations, such as applied research and training, with approaches that foster innovation and promote institutional and policy change. Specifically, AAS utilizes participatory action research with communities to identify technology and policy solutions that best meet community long-term needs. One of the themes identified under AAS is the role of self-help groups in increasing livelihood resilience of agriculture and fisheries communities. As AAS establishes a hub of operations in Cambodia, AAS and Oxfam America are cooperating to investigate the potential of community-based self-help groups as a strategy for AAS implementation. As part of this cooperation, Oxfam America undertook this consultancy to analyze and describe the role, efficiency and effectiveness of the various types of self-help groups in Cambodia. This report gives an overview of this program which aims to conduct a field-based study to identify the types, main characteristics and effectiveness of self-help groups, with a particular focus on livelihood resilience of agriculture and fisheries communities.

What needs to be done?: Guide in mangrove reforestation

The article presents a two-part guideline in mangrove reforestation. The first part is zonation, which is the process of determining what species are particularly suited to plant in a particular site. While, plantation establishment is the second part, it includes guides in the identification of species, selection of planting site, preparation of the planting sites, seed collection, handling and transporting of seeds, and planting.

Identification and distribution of cartilaginous fishes of the Persian Gulf (Bushehr Province waters)

Class Condrichthyes consist of two sub-classes: Holocehali and. Elasmobranchii, the second one are more divers and has more importance. Selachimorpha (sharkes) and Batidoidimorpha (rays and skates) are two super-order of Elasmobranchii, which they have crucial role in ecological balance in marine ecosystmes. Except few cases, most of sharks and rays (rays and skates) are not well identified, so a lot of works need to be done in this regards. The area of study is located between 49°, 35' and 52°, 33' E and between 27°, 21' and 30°, 02' N in depth of 7 to 78 in. Study were conducted diuring August 1998, September 1999. Samples were taken during 3 sea cruises from 70 bottom trawl net. All sharks and batoid fishes were identified based on biometric specifications (weight, total, length and sexuality for both group and extra biometric specifications, disc width, disc length, and tail length only for, batoid fishes). The 1140 specimens of batoid fishes identified belonged to 6 families, and 18 species. 3 new species were identified, they are Himantura sp.1 and Himantura sp.2 belonged to Dasyatidae family and Rhinobatos sp. belonged to Rhinobatidae Familiy. It needs more works and more adaquate ducuments for cl.earfing scientific names of these species. The 275 specimens of sharks identified belonged to 6 families and 10 species. Chiloscyllium sp. belonged to Hemiscylliidae, family as a new species was identified.

Separation and identification fresh water leeches of waters resources in Kordistan Province

In the primary studying, known leeches have included into free living and parasitic which the parasitic group, besides of direct impacts like: growth detraction, anemia, making wound in the connecting part with the skin, with making plat for secondary bacterial and molding infections in the toll place, is able to cause to transfer blood flagellate and virus to the fish too. Therefore, by accusing information related to fauna leeches of each area a risk factor from the viewpoint of the possibility of being or accusing transferred diseases by these leeches, one can predict and forehand about them. Freshwater leeches of Iran to present accurate recognition (morphological, molecular) have not been, and there are some limited reports from different parts of the country about them. One of the areas that its leeches have not been identified yet is Kurdistan, By having five latrines and big permanent rivers and 32000 springs and a lot of deep and semi-deep wells and this province is a convenient bed for growing aquatics in the country. Therefore, identifying risk factors for development of aquaculture on water resources is one important factor to access achieving development goals. For recognizing leeches of this province, some samples from 10 stands were token. Samples from under stones, sticking to the fish, turtles, plants and solid substances in the water were separated and after recording their physical characteristics, calming with 10% ethylic alcohol with 10% formalin become fixed and after painting with Carmen acetic acid by standard keys for 7 species of Helobdella stagnalis, Placobdella costata, Hemiclepsis marginata, Erpobdella octoculata, Hirudo medicinalis, Dina lineate lineata have been identified and described. Which Helobdella stagnalis has the highest distribution in the province and the minimum one is Hirudo medicinalis. However, that the data obtained in leeches in Kurdistan is a relatively complete collection in this research, recognizing fauna of these areas needs more studying. The Placobdella costata and Hemiclepsis marginata sticking to the fish were separated among identified species which showed that these are parasites for the fish. The sticking area of those leeches to the skin was accompanied with scales cast, damage to mucous membranes beneath the parasite and bleeding Was associated with Histopathology studying effect includes observing break and disconnection in the leech connecting place to the epithelial layer of epidermis in the skin, destroyed nucleus in skin Epithelial cells with observing necrosis in ulcerative place become of the leech and the sub acute inflammated penetration until acute necrosis with opening in Dermis layer is observable. Kidney of this fish have changes such as: proliferation, like proliferative kidney disease with increasing proliferative glomerular cells and increasing in membranous cells in Capillary corpuscle, observing necrotic cells in haematopoietic tissue of kidney along with increasing in infiltration of leukocyte's cells generally mono nucluars such as lymphocytes and less poly morpho nucluars such as neutrophiles that are symptoms of disorders causing anemia become of nourishing and sucking blood by the leech and creating a chronic kidney infection that originally root is in another place like the skin. Also Hemorrhagic anemia causes losing RBC's is because of using the host blood by the leech. (In this situation, one can see immature RBC red cells in Peripheral blood. To identify potential carriers of the leech to the viruses, after finding them in recorded stands and putting them in 75% ethanol for viruses cause IPN, VHS, IHN, they were tested by PCR that the conclusion of these experiments approved IPN virus in Hemiclepsis marginata and Hirudo medicinalis. This kind of leeches can act like a mechanical carrier and causing spreading the agent of this disease. It is worth mentioning that studying the pathogenicity of this virus for aquaculture sources, mentioned before needs more research. During the study of infected fish with leeches that was done after preparing bloody slides and staining them, no case blood parasites was observed. During a research about infecting fish experimentally to known leeches it become clear that 5 days after being in aquarium including leeches, samples of sticking Hirudo medicinalis leech to the golden carp with scales cast were observed. Including leeches to the fish started with molting the scales in the sticking area in the fish and fish become too uneasy and by rubbing themselves to the malls and things inside the aquarium, tried to separate them. Finally, after around 30 hours, leeches penetrate the skin, feeding from blood and tissue liquids and cause mortality the fish and then they become separated from them. If the corpse of these fish stayed in the aquarium, the Helobdella stagnalis and Erpobdella octoculata would start feeding them.