Production and carbonate dynamics of Halimeda incrassata (Ellis)Lamouroux altered by Thalassia testudinum Banks and Soland ex König

Ocean acidification poses a serious threat to a broad suite of calcifying organisms. Scleractinian corals and cal- careous algae that occupy shallow, tropical waters are vulnerable to global changes in ocean chemistry be- cause they already are subject to stressful and variable carbon dynamics at the local scale. For example, net heterotrophy increases carbon dioxide concentrations, and pH varies with diurnal fluctuations in photosyn- thesis and respiration. Few researchers, however, have investigated the possibility that carbon dioxide con- sumption during photosynthesis by non-calcifying photoautotrophs, such as seagrasses, can ameliorate deleterious effects of ocean acidi fi cation on sympatric calcareous algae. Naturally occurring variations in the density of seagrasses and associated calcareous algae provide an ecologically relevant test of the hypoth- esis that diel fl uctuations in water chemistry driven by cycles of photosynthesis and respiration within seagrass beds create microenvironments that enhance macroalgal calci fi cation. In Grape Tree Bay off Little Cayman Island BWI, we quanti fi ed net production and characterized calci fi cation for thalli of the calcareous green alga Halimeda incrassata growing within beds of Thalassia testudinum with varying shoot densities. Re- sults indicated that individual H . incrassata thalli were ~6% more calci fi ed in dense seagrass beds. On an areal basis, however, far more calcium carbonate was produced by H . incrassata in areas where seagrasses were less dense due to higher rates of production. In addition, diel pH regimes in vegetated and unvegetated areas within the lagoon were not signi fi cantly different, suggesting a high degree of water exchange and mixing throughout the lagoon. These results suggest that, especially in well-mixed lagoons, carbonate pro- duction by calcareous algae may be more related to biotic interactions between seagrasses and calcareous algae than to seagrass-mediated changes in local water chemistry.

River habitat survey and geomorphological evaluation of the Glaze Brook Catchment

This is the River habitat survey and geomorphological evaluation of the Glaze Brook Catchment report produced by the Environmental Research and Consultancy of the University of Liverpool in 2002. The major aims of the project were to provide baseline information on river habitats in the Glaze catchment using standard River Habitat Survey (RHS) methods (sampling 25% of the catchment length) and, through the geomorphological audit, to assess the distribution and intensity of geomorphological processes, notably sediment transfer, sources and sinks. This information was then used to develop informed management recommendations. The Glaze catchment is a heavily modified watercourse of generally poor habitat quality. The most important factors contributing to the low quality of the sites are poor bank and channel features; low diversity/absence of channel vegetation; paucity of bankside trees and, to a lesser extent, a lack of channel substrate diversity. The high degree of modification relates principally to extensively resectioned banks and channels plus extensive culverting in the urban parts of the catchment.

Spatial and temporal patterns in the demersal fish community on the shelf and upper slope regions of the Gulf of Alaska

We analyzed data from National Marine Fisheries Service bottom trawl surveys carried out triennially from 1984 to 1996 in the Gulf of Alaska (GOA). The continental shelf and upper slope (0–500 m) of the GOA support a rich demersal fish fauna dominated by arrowtooth flounder (Atheresthes stomias), walleye pollock (Theragra chalcogramma), Pacific cod (Gadus macrocephalus), Pacific halibut (Hippoglossus stenolepis), and Pacific Ocean perch (Sebastes alutus). Average catch per unit of effort (CPUE) of all groundfish species combined increased with depth and had a significant peak near the shelf break at 150–200 m. Species richness and diversity had significant peaks at 200–300 m. The western GOA was characterized by higher CPUEs and lower species richness and diversity than the eastern GOA. Highest CPUEs were observed in Shelikof Strait, along the shelf break and upper slope south of Kodiak Island, and on the banks and in the gullies northeast of Kodiak Island. Significant differences in total CPUE among surveys suggest a 40% increase in total groundfish biomass between 1984 and 1996. A multivariate analysis of the CPUE of 72 groundfish taxa revealed strong gradients in species composition with depth and from east to west, and a weak but significant trend in species composition over time. The trend over time was associated with increases in the frequency of occurrence and CPUE of at least eight taxa, including skates (Rajidae), capelin (Mallotus villosus), three flatfish species, and Pacific Ocean perch, and decreases in frequency of occurrence and CPUE of several sculpin (Myoxocephalus spp.) species. Results are discussed in terms of spatial and temporal patterns in productivity and in the context of their ecological and management implications.

Fishermen cooperatives in the Green Revolution Programme

The aim of this study was to examine areas in which fishermen cooperatives can become involved and then suggest operational guidelines in order to increase fishermen income and also to make the Green Revolution Programme a success through increased production of fish. The paper enumerated different areas in which fishermen cooperatives can participate. These include: thrift and credits, thrift and savings, consumers and building cooperative societies. It is the belief of the author that the expansion of fishermen cooperatives into the areas mentioned in this paper can enable members to process and market their products more economically, buy supplies and equipment in large quantities and obtain lower cost credit

Human Resources Development for Sustainable Aquaculture in Bangladesh

The ennoblement of human resources has become a prime issue in the philosophy of sustainable aquaculture development in the new millennium.Being the planners, designers, conductors and philosophers of sustainable aquaculture, human beings always demand their further improvement at level best from their current positions to bring supreme success in the sector. As sustainable aquaculture is socio-economic –cum-environmental in concept, its operation and management requires constant interplay of various human knowledge for ensuring its smooth direction and for achieving its goal. So, the arrangement of different types and levels of training and education are the great need for the development of personnel involved in sustainable aquaculture route and also for growing awareness of environmental issues. The modus operandi of training and education has to be changed systematically to answer the calls of the needs of the new millennium. In the developing and developed countries where aquaculture plays a vital role in promoting production of aquatic organisms, alleviating of poverty, ensuring environmental compatibility, replenishing and improving the natural stocks, increasing socio-economic upliftment through integrated development approach, developing and managing the aquatic resources, maintaining gene banks and preserving the diversity of fish stocks, it has been already proved that Human resources development (HRD) is inevitable to bring sustainable aquaculture and plays a great role in the flourishment of the system . Different types and levels of training of personnel required for sustainable aquaculture in the new millennium are brought forward in the study. The importance of human resources development (HRD) through specialized training to the personnel is also depicted.

Les macrophytes aquatiques des berges lagunaires

This synthetic article describes the composition and organization of vegetations colonizing the Ebrié lagoon banks and provides original data on the recent evolution of this association consecutively to the accidental introduction of 2 new species of floating macrophytes (Salvinia molesta and Eichhornia crassipes).

The use of multibeam sonar mapping techniques to refine population estimates of the endangered white abalone (Haliotis sorenseni)

Multibeam sonar mapping techniques provide detailed benthic habitat information that can be combined with the data on species-specific habitat preferences to provide highly accurate calculations of populations in a particular area. The amount of suitable habitat available for the endangered white abalone (Haliotis sorenseni) was quantified to aid in obtaining an accurate estimate of the number of remaining individuals at two offshore banks and one island site off the coast of southern California. Habitat was mapped by using multibeam sonar survey techniques and categorized by using rugosity and topographic position analysis. Abalone densities were evaluated by using a remotely operated vehicle and video transect methods. The total amount of suitable habitat at these three sites was far greater than that previously estimated. Therefore, although present estimates of white abalone densities are several orders of magnitude lower than historic estimates, the total population is likely larger than previously reported because of the additional amount of habitat surveyed in this study.

Prospects for fish culture in char areas of Bangladesh

Fish production is considered in the barren chars or sandy land masses created through siltation along river banks and deltas in Bangladesh. The prospects for fish culture in ponds and cages or pen culture in rivers and canals are examined. The socioeconomic implications of fish culture as a livelihood source for communities living in char areas are also discussed.

MDNR-NOAA trawl standardization study

Long-term living resource monitoring programs are commonly conducted globally to evaluate trends and impacts of environmental change and management actions. For example, the Woods Hole bottom trawl survey has been conducted since 1963 providing critical information on the biology and distribution of finfish and shellfish in the North Atlantic (Despres-Patango et al. 1988). Similarly in the Chesapeake Bay, the Maryland Department of Natural Resources (MDNR) Summer Blue Crab Trawl survey has been conducted continuously since 1977 providing management-relevant information on the abundance of this important commercial and recreational species. A key component of monitoring program design is standardization of methods over time to allow for a continuous, unbiased data set. However, complete standardization is not always possible where multiple vessels, captains, and crews are required to cover large geographic areas (Tyson et al. 2006). Of equal issue is technological advancement of gear which serves to increase capture efficiency or ease of use. Thus, to maintain consistency and facilitate interpretation of reported data in long-term datasets, it is imperative to understand and quantify the impacts of changes in gear and vessels on catch per unit of effort (CPUE). While vessel changes are inevitable due to ageing fleets and other factors, gear changes often reflect a decision to exploit technological advances. A prime example of this is the otter trawl, a common tool for fisheries monitoring and research worldwide. Historically, trawl nets were constructed of natural materials such as cotton and linen. However modern net construction consists of synthetic materials such as polyamide, polyester, polyethylene, and polypropylene (Nielson et. al. 1983). Over the past several decades, polyamide materials which will be referred to as nylon, has been a standard material used in otter trawl construction. These trawls are typically dipped into a latex coating for increased abrasion resistance, a process that is referred to as “green dipped.” More recently, polyethylene netting has become popular among living resource monitoring agencies. Polyethylene netting, commonly known as sapphire netting, consists of braided filaments that form a very durable material more resistant to abrasion than nylon. Additionally, sapphire netting allows for stronger knot strength during construction of the net further increasing the net’s durability and longevity. Also, sapphire absorbs less water with a specific gravity near 0.91 allowing the material to float as compared to nylon with specific gravity of 1.14 (Nielson et. al. 1983). This same property results in a light weight net which is more efficient in deployment, retrieval and fishing of the net, particularly when towing from small vessels. While there are many advantages to the sapphire netting, no comparative efficiency data is available for these two trawl net types. Traditional nylon netting has been used consistently for decades by the MDDNR to generate long term living resource data sets of great value. However, there is much interest in switching to the advanced materials. In addition, recent collaborative efforts between MDNR and NOAA’s Cooperative Oxford Laboratory (NOAA-COL) require using different vessels for trawling in support of joint projects. In order to continue collaborative programs, or change to more innovative netting materials, the influence of these changes must be demonstrated to be negligible or correction factors determined. Thus, the objective of this study was to examine the influence of trawl net type, vessel type, and their interaction on capture efficiency.

Institutional support for freshwater aquaculture development: a study of Mirzapur district of Uttar Pradesh, India

The aquaculture sector has been playing an increasingly dominating role in Indian fisheries scenario since the last two and half decades. Introduction of induced breeding and composite fish culture (CFC) technologies has changed the freshwater aquaculture sector in India. Institutional support has been one of the most crucial aspects in all fisheries development programs, more so in the Indian context where most of fish farmers are socially and economically weak. The innovation of CFC technology in freshwater aquaculture sector in the early seventies generated the need for adequate and effective institutional support to farmers. Under the freshwater aquaculture development program, the Fish Farmers Development Agencies (FFDA) have been established at district level to provide technical and extension support to the farming community besides arranging ponds on lease and supply of seeds. In addition to above, FFDAs are also expected to arrange loans from banks and provide subsidies. Thus, FFDAs are meant to provide institutional support to fish farming community in the country. In view of the above, an effort was made to study the adequacy and effectiveness of institutional support provided by the FFDA, Mirzapur for the development of aquaculture in Mirzapur district of Uttar Pradesh {U.P.), India. Study reveals that leasing of ponds for fish farming has been favourable to economically weaker sections of societies while bank loan accessibility is more for those having relatively higher economic status. Though the FFDA, Mirzapur performed well in providing training to potential fish farmers and creating awareness about fish farming, its effectiveness could not be equally seen in seed supply.