aquaculture

The Native Fish Conservancy is about preserving the North American aquatic heritage. A group of like-minded conservationists, they are seeking other people, willing to donate time and skills to the ongoing development and production of the e-newsletter, the web site, and marketing. The Native Fish Conservancy is a not-for-profit, volunteer run organisation. Although their emphasis is on North American species, no doubt they would welcome international members. From a more commercial aquacultural perspective, a lot can be learned from people who keep fish as a hobby – people who have the time and resources to carefully develop breeding, feeding, and raising strategies that could be scaled into full scale commercial enterprises.

K. F. Shim and S. I. Ong, from the Department of Zoology, National University of Singapore, published a research document entitled ‘Iron requirement of the guppy (Poecilia reticulata Peters)’ in the Journal of Aquariculture & Aquatic Sciences, Volume 6, Number 2. The publication is available from petsforum.com.

From the abstract:

The iron requirement of the guppy, Poecilia reticulata Peters, was determined by feeding them eight different levels of iron (0.0, 0.010, 0.020, 0.040, 0.080, 0.320, and 0.640 g/kg dry diet) for fifteen weeks. Growth and feed conversion was not significantly affected by the dietary iron. The red blood cell count, hemoglobin content, and hematocrit value was significantly reduced in fish fed an iron-deficient diet. Iron, copper and zinc content of the liver, spleen, kidney, blood, skin and muscle, heart, gills, and ovary was determined. The iron content was significantly lower in fish fed the iron-deficient diet while the copper content was significantly elevated. However, the zinc content in the organs was not affected by the levels of iron in the diets. the level of iron required by the guppy to prevent microcytic, hypochromic anemia was found to be 0.080 g/kg of diet.

It could be considered to be quite unusual to find an academic from a scientific discipline to have a flair for the aesthetic. Luis Rocha manages the combination with aplomb. He has created a web site about coral reef fishes superbly illustrated with his own photographs.

Rocha explains some of the attractions of coral reefs:

The most striking feature of reef fish is their diversity, in terms of both species number and the range of morphologies. An estimated 4000 (18% of all living fishes) species of fish live on coral reefs and associated habitats of the Indo-Pacific and Atlantic oceans, and this number increases as new exploratory surveys are done.

Further examples of his reef fish photographs can be found at his online gallery. As might be expected from his scientific background, the photographs are not only beautiful, they are meticulously accurate.

Siamensis Group was formed by a group of people who met online. Their love of freshwater fish and aquatic plants brought them together to make their dream come true – a website about Thai fish and their husbandry. Siamensis Group is an independent non-profit group working to save Thai freshwater fish, aquatic plants, and their habitat.

They note there seems to be fewer and fewer clean bodies of fresh water for fish to live. Illegal deforestation, damming, and polluted water from factories represent a direct impact to the rivers and ponds the fish and plants called home. Some fish species are now declining at a very fast pace; some are feared already extinct.

The Siamensis Group’s ultimate goal is to make sure the continuous existence of Thai fish and plants. They believe that if people are aware of what aquatic life is in the water around them, they would like to protect it. The main part of their website is dedicated to reports from their survey trips. In the survey reports they note what species of fish and plants were found. If possible, they re-visit the location to collect more data and to update the current situation. Most of the reports are written in Thai, some English translations can be found at the bottom of the page. There are beautiful photographs on all pages, so even if you can’t read in Thai, the pages are well worth a look.

The Center for Tropical and Subtropical Aquaculture (CTSA) is one of five regional aquaculture centers in the United States established by the U.S. Department of Agriculture. The regional aquaculture centers integrate individual and institutional expertise and resources in support of commercial aquaculture development.

The Center produces a number of publications, including this ‘Manual for Commerical Production of the Gourami, Trichogaster trichopterus, a Temporary Paired Tank Spawner‘.

Gouramis are commonly known as labyrinth fishes. These fish are characterized primarily by an accessory breathing organ called the labyrinth organ. The labyrinth organ is located next to the gill cavities and is made up of folded membranes mounted on a bony frame. The delicate tissue has a high concentration of blood vessels and functions much like a terrestrial lung. If a labyrinth fish is denied access to the air it will drown because the gills alone will not provide sufficient oxygen to the fish.

This ‘lung’ adaptation is essential in the oxygen depleted waters that are home to gouramis. The image below shows typical Trichogaster habitat.