Integration of technologies for understanding the functional relationship between reef habitat and fish growth and production

Functional linkage between reef habitat quality and fish growth and production has remained elusive. Most current research is focused on correlative relationships between a general habitat type and presence/absence of a species, an index of species abundance, or species diversity. Such descriptive information largely ignores how reef attributes regulate reef fish abundance (density-dependent habitat selection), trophic interactions, and physiological performance (growth and condition). To determine the functional relationship between habitat quality, fish abundance, trophic interactions, and physiological performance, we are using an experimental reef system in the northeastern Gulf of Mexico where we apply advanced sensor and biochemical technologies. Our study site controls for reef attributes (size, cavity space, and reef mosaics) and focuses on the processes that regulate gag grouper (Mycteroperca microlepis) abundance, behavior and performance (growth and condition), and the availability of their pelagic prey. We combine mobile and fixed-active (fisheries) acoustics, passive acoustics, video cameras, and advanced biochemical techniques. Fisheries acoustics quantifies the abundance of pelagic prey fishes associated with the reefs and their behavior. Passive acoustics and video allow direct observation of gag and prey fish behavior and the acoustic environment, and provide a direct visual for the interpretation of fixed fisheries acoustics measurements. New application of biochemical techniques, such as Electron Transport System (ETS) assay, allow the in situ measurement of metabolic expenditure of gag and relates this back to reef attributes, gag behavior, and prey fish availability. Here, we provide an overview of our integrated technological approach for understanding and quantifying the functional relationship between reef habitat quality and one element of production – gag grouper growth on shallow coastal reefs.

Effects of underwater explosions on oysters, crabs and fish: a preliminary report.

Investigation on the effects of explosive shock on marine life. Necessary that the "commercial" effects, the actual damage to commercially important stocks of fish and shellfish, be evaluated. Equally important are the "biological" effects, the immediate physical effects of shock waves on animals and the indirect effects on future stocks. Indirect effects might include the diversion of migratory stocks from an area, or actual damage to the habitat, rendering it unfit for sedentary or non-migratory native species. Interruption of the food chains in an area by destruction of forge forms or vegetation. (PDF contains 43 pages)

The Affects of acid mine drainage on the water quality, and benthic macroinvertebrate and fish population in streams in Maryland

The purpose of this study was to measure and evaluate relationships between populations of benthic macroinvertebrates and fish, as well as variations in water quality in streams affected by acid Mine drainage. (PDF contains 21 pages)

Preliminary studies of the dual role of cotton-seed cake as fish feed and fish pond fertilizer in aquaculture

Many locally available fish feeds have been tried in fish culture. These include guinea corn, soya bean, groundnut cake and rice bran. Cotton seed cake has been successfully used as a fishpond organic fertilizer at Ado-Ekiti Government fish farm. Three fishponds stocked respectively with common carps, Heterotis, Tilapia spp., Clarias lazera and Heterobranchus were fed with cotton seed cake. Carps, Tilapia and Heterotis increased rapidly in weight and length while the catifishes did not grow

Aspects of the fishing industry and an overview of artificial reefs and fish aggregating devices for increasing fisheries output and viability in Nigeria

Aspects of the Nigerian fishing industry are outlined to explain the concept of fishing systems viability which is often influenced by a combination of factors including biological productivity, as well as technical, economic and social factors. The productivity of the aquatic environments can be increased by the construction and installation of artificial reefs and fish aggregating devices. These man-made structures provide shelters, food and breeding grounds for fin fish and shell fish. The habitat enhancement techniques are appropriate, efficient, cheap and simple strategic options for increase in fish production. Recommendations for effective utilization and long term management are outlined.

Recruitment pattern and fish production within the Andoni River system in the Niger Delta of Nigeria

Biweekly samples of fish species obtained from five randomly selected Andoni artisanal fisheries within the Andoni River system, Niger Delta of Nigeria were collected between January and December 1999 and their length frequencies analyzed using FISAT (FAO-ICLARM STOCK ASSESSMENT TOOL). The peak recruitment period for Chrysichthys nigrodigitatus, Ethmalosa fimbriata, Eucinostomus melanopterus, Galeodes decadactylus, Pomadasys jubelini and Sarotherodon melanotheron constituting 54.55% was between June and October while Liza grandisquamis and Lutjanus goreensis, Ilisha Africana. Tilapia guinensis and Pseudotolithus elongate constituting 27.27% had two peak recruitment periods including March-May and May- October. In view of this result it is advisable for fishers to intensify fishing effort between May and October for most commercially important fish species for bountiful harvest

Estimation of growth and financial analysis through the application of Ipil ipil (Leucaena leucocephala) leaf meal as supplements to soybean and fish meal in the diet of juvenile monosex tilapia (Oreochromis niloticus)

Among plant protein ingredients,ipil ipil (Leucaena leucocephala) leafmeal (ILLM) is considered the most nutritive plant protein source after soybean meal in aquatic feeds. That was proven in a 21-day experiment conducted to assess the response of juvenile Monosex Nile tilapia Oreochromis niloticus with four iso-nitrogenous formulated diets: One control diet was formulated based on fishmeal, one on soybean meal and one on rice bran, ipil ipil leafmeal was also included in experimental diets.

The relationship between boat size and fish catches in the gillnet fishery of Lake Victoria, Uganda

The number and size composition of gillnets, fishing grounds, and the quantity and composition of fish catches were related to the size of fishing boat. The overall number of gillnets per boat increased from 20.9 + or - 2.3 nets in 5-6 m long boats to 88.6 + or - 11.8 nets in 11-12 m long boats. The proportion of large mesh sizes, + or more than 127 mm, also increased from 40% in 5-6 m long boats to 100% in boats longer than 10 m. Fish catches are related to the size of boat and this should be considered when formulating management guidelines of the lake's fishery. Promotion of large fishing boats 8 m or longer and restriction on the number and/or mesh size of gillnets of smaller boats could increase ecological and socio-economic benefits.

Review of aquaculture and fish consumption in Bangladesh

Fish play a crucial role in the Bangladeshi diet, providing more than 60% of animal source food, representing a crucial source of micro-nutrients, and possessing an extremely strong cultural attachment. Fish (including shrimp and prawn) is the second most valuable agricultural crop, and its production contributes to the livelihoods and employment of millions. The culture and consumption of fish therefore has important implications for national food and nutrition security, poverty and growth. This review examines the current state of knowledge on the aquaculture sector and fish consumption in Bangladesh, based on extensive analysis of secondary sources (including unpublished data unavailable elsewhere), consultation with various experts and specially conducted surveys.

Description of NRA tracking studies: tracking techniques and fish counter technology

The study began on the 7th January 1991 and was completed in June 1991. Two reports have been produced. This report published as R&D Note 33 describes NRA tracking studies, tracking techniques and fish counter technology. The second report published as R&D Note 34 evaluates NRA tracking studies and recommends future research. The latter will be used solely for NRA management purposes. This report briefly outlines the programme of the NRA, placing the Fisheries programme in the context of the work of the NRA as a whole, and viewing the tracking work against the broader requirements of the NRA Fisheries research programme. Two techniques currently exist for studying the detailed timing and extent of movements of adult salmon: tracking of individually identifiable fish, and counting the numbers of fish moving past a fixed point in the river. Further details of these techniques and their development are given in Sections 2 and 3. Section 4 summarises and assesses completed and current NRA tracking Studies. Complete project descriptions for the studies are contained in Appendix A. Section 5 discusses the scientific content of these studies in relation to similar work carried out elsewhere in the UK. Section 6 details the future development of tracking techniques. Tracking work on migratory salmonids has tended to concentrate largely upon the movements of adult salmon. Much of this report will therefore be concerned with salmon tracking studies. NRA studies involving sea trout are referred to where appropriate. The methodological problems of sea trout tracking studies are summarised in Section 2.1.3.