aquaculture

Viral haemorrhagic septicaemia (VHS) was initially noted as a disease of cultured European rainbow trout (Oncorhynchus mykiss). The disease has been noted amongst marine species, notably farmed turbot (Germany, Scotland and Ireland), but until relatively recently (approximately Spring 2005), appears to have been restricted to Europe. Dr. Robert S. Bakal, of the U.S. Fish & Wildlife Service’s Division of the National Fish Hatchery System, reports from a conference on VHS held in August 2006,

…leading expert on VHS in the United States, Jim Winton of the US Geological Survey, indicated that the VHS virus exists in four strains, with a single, unique sub-strain occurring in the Great Lakes. The VHS virus has been known in Europe, Japan, and the coasts of the U.S. for many years; how it came to occur in the Great Lakes is not known. Winton speculates that it may have originated in ballast water from ocean-going ships sailing into the Great Lakes, or that it may have hitchhiked in shipments of hatchery-raised fish.

According to the New York State Department of Environmental Conservation (NYSDEC),

Viral hemorrhagic septicemia (VHS) virus is a serious pathogen of fresh and saltwater fish that is causing an emerging disease in the Great Lakes region of the United States and Canada. VHS virus is a rhabdovirus (rod shaped virus) that affects fish of all size and age ranges. It does not pose any threat to human health. VHS can cause hemorrhaging of fish tissue, including internal organs, and can cause the death of infected fish. Once a fish is infected with VHS, there is no known cure. Not all infected fish develop the disease, but they can carry and spread the disease to other fish. VHS has been blamed for fish kills in Lake Huron, Lake St. Clair (MI), Lake Erie, Lake Ontario, the St. Lawrence River and Conesus Lake (Western NY). The World Organization of Animal Health has categorized VHS as a transmissible disease with the potential for profound socio-economic consequences. Because of this, they list VHS as a disease that should be reported to the international community as an exceptional epidemiological (study of diseases in large populations) occurrence.

The NYSDEC has released revised Emergency Regulations Adopted to Prevent Spread of VHS.

Animal and Plant Health Inspection Service (APHIS) note the following species are susceptable: Atlantic cod Gadus morhua, Black crappie Pomoxis nigromaculatus, Bluegill Lepomis macrochirus, Bluntnose minnow Pimephales notatus, Brown bullhead Ictalurus nebulosus, Brown trout Salmo trutta, Burbot Lota lota, Channel catfish Ictalurus punctatus, Chinook salmon Oncorhynchus tshawytscha, Coho salmon Oncorhynchus kisutch, Chum salmon Oncorhynchus keta, Emerald shiner Notropis atherinoides, Freshwater drum Aplodinotus grunniens, Gizzard shad Dorosoma cepedianum, Grayling Thymallus thymallus, Haddock Gadus aeglefinus, Herring Clupea spp, Japanese flounder Paralichthys olivaceus, Largemouth bass Micropterus salmoides, Muskellunge Esox masquinongy, Pacific cod Gadus macrocephalus, Pike Esox lucius, Pink salmon Onchorhynchus gorbuscha, Pumpkinseed Lepomis gibbosus, Rainbow trout Oncorhynchus mykiss, Redhorse sucker Moxostoma spp, Rock bass Ambloplites rupestris, Rockling Onos mustelus, Round goby Neogobius melanostomus, Smallmouth bass Micropterus dolomieu, Sprat Sprattus spp, Turbot Scophthalmus maximus, Walleye Sander vitreus, White bass Morone chrysops, White perch Morone americana, Whitefish Coregonus spp, Yellow perch Perca flavescens.

APHIS has also released the Amended Federal Order Viral Hemorrhagic Septicemia (VHS) dated May 4, 2007. The purpose of this Federal Order is to prevent the spread of viral hemorrhagic septicemia (VHS) into aquaculture facilities. Also refer to the APHIS July 2006 Emerging Disease Notice – Viral Hemorrhagic Septicemia in the Great Lakes for further analysis.

Research reports published from the Scottish Fisheries Research Services may serve to provide management options:
Viral Haemorrhagic Septicaemia (VHS) – from the abstract:

Viral haemorrhagic septicaemia (VHS) was diagnosed inrainbow trout (Oncorhynchus mykiss) at a farm in Englandon 26 May 2006. VHS is a notifiable disease in the UK and a List II disease under European Directive 91/67/EEC. Investigations into the source and potential spread of the disease are being carried out by Centre for Environment, Fisheries and Aquaculture Science (Cefas) in England and Wales, and by Fisheries Research Services (FRS) in Scotland. VHS has occurred once before in the UK, in 1994, affecting a single turbot farm. The disease was successfully eradicated on that occasion. VHS has no implications for human health.

Risks to Wild Freshwater Fisheries from Viral Haemorrhagic Septicaemia (VHS) – from the abstract:

There is a risk of transfer of VHSV from farmed to wild freshwater fish species and vice versa. There is evidence that a reservoir of infection may be created in wild freshwater fish species. This may pose a risk of re-infection of farms (eg rainbow trout). There are no reports of VHSV infection leading to significant disease outbreaks in wild freshwater fish stocks. Based on evidence from outbreaks in farms and experimental evidence, free living rainbow trout, brown trout, whitefish, grayling and pike may be at risk of disease. Available evidence suggests a high infection pressure would be required to initiate a disease outbreak in wild fish (eg shedding of virus from an infected farm).

Disinfection guide version IV: practical steps to prevent the introduction and minimise transmission of diseases of fish – from the abstract:

Emerging diseases have had a significant impact on development of the Scottish aquaculture industry, highlighting the importance of preventing their introduction and minimising their transmission. The risk of disease spread is reduced by the implementation of good sanitary practices by fish farmers, and fisheries and the application of effluent disinfection systems in the processing industry. To maintain healthy fish stocks and minimise the introduction and spread of disease, the aquaculture industry should ensure best practice on farm sites, during transportation of live or dead fish and equipment, at the processing plant and during subsequent effluent and waste disposal. For an assessment of the risks associated with specific tasks, reference should be made to the Final Report of the Joint Government/ Industry Working Group on Infectious Salmon Anaemia (ISA) available from the Fisheries Research Services (FRS) web site, at www.frs-scotland.gov.uk. The protocols described in this guide are based upon current scientific knowledge and practical experience and will continue to be developed as the needs of industry change. This guide is intended for distribution to relevant industry personnel.

R. J. Slack-Smith has written and the FAO published a manual entitled Fishing with Traps and Pots. It describes the basic elements of fishing with traps and pots for small-scale fishermen. It presents the various types of traps and pots and their construcion and gives guidance on how to choose the appropriate gear, how to rig it, how to use it to improve the catch, how to select places to fish, soaking time and finally care of the catch. The document is also available (as a .pdf) for download.

From Chapter 1:

Fishing is one of the oldest ways by which people have fed themselves and their families. Except for gathering shellfish by hand and spearing fish, primitive trapping is probably the oldest form of fishing.

In early times, flowing water caused by tidal movement and changes in river and lake levels were probably used to trap fish behind rudimentary barriers, often made from sticks and stones. It is likely that early humans found that fish catches could be improved by driving fish into these barriers. They would have found that catches from these barriers decreased over time, as fish became accustomed to them, and would have had to move the traps to fresh areas where more fish could be caught. It would have been hard work to construct new traps, either by moving stones from the old trap or finding new ones. Primitive fishers probably tried making barriers from lighter, more readily available material such as tree branches, brush and vines. This led to the fishers inventing lighter, movable traps made from brush and nets made from vines which they could carry with them when they moved to new areas. They may even have tried bigger, more complicated corral-type fish traps in lakes, rivers and coastal waters.

Marine Aquaculture: Opportunities for Growth (1992) is available, online as a free book (.pdfs), and also can be bought as a hard copy. The big advantage of the .pdf document, apart from the agreeable price, is the ability to search on any word, across the document.

The authors, the Committee on Assessment of Technology and Opportunities for Marine Aquaculture in the United States, and the Marine Board, Commission on Engineering and Technical Systems, National Research Council appear to have completed a comprehensive job – the Table of Contents:

Front Matter i-xii
Executive Summary 1-8
Introduction 9-19
Status of Aquaculture 20-63
Policy Issues 64-91
Environmental Issues 92-115
Engineering and Research 116-157
Information Exchange, Technology Transfer, and Education 158-168
Conclusions and Recommendations 169-177
Bibliography 178-205
Appendix A: Review of World Aquaculture 206-231
Appendix B: Freshwater Aquaculture in the United States 232-240
Appendix C: Federal Marine Aquaculture Policy 241-152
Appendix D: Sociocultural Aspects of Domestic Marine Aquaculture 253-268
Appendix E: Committee Biographies 269-273
Appendix F: Participants in Special Sessions 274-276
Index 277-290

Alfred J. Römer has published a report about the pearl cultivation in New Zealand – specifically on the pearls and abalone (Paua – Haliotis iris) cultured by Rainbow Abalone Ltd©, New Plymouth, New Zealand.

From the report:

This sea snail, which grows up to 18 cm in length and 13 cm wide, is the New Zealand representative of some hundred Abalone species found world-wide. Its underwater habitat is from a depth close to the surface to approximately 30 meters, where the water is not only clear and rich on oxygen, but where seaweed grows in larger amounts.

Sea cucumbers (Bêche-de-mer) are echinoderms – in the class Holothuroidea. They are generally scavengers, feeding on plankton and other organic debris in the bottom sediments. They often found in substantial numbers beneath fish farms. Sea cucumbers are considered delacacies in China, Indonesia, Japan, Korea, and Malaysia; and some varieties are respected for their properties as an ingredient in traditional medicines. Sea cucumbers have been called ‘Ginseng of the Sea’.

B.H. Ridzwan, T.C. Leong and S.Z. Idid have published a document entitled The Antinociceptive Effects of Water Extracts from Sea Cucumbers Holothuria leucospilota Brandt, Bohadschia marmorata vitiensis Jaeger and Coelomic Fluid from Stichopus hermanii. This document is not always available – listed here from the web archive. An antinociceptive is an agent for deadening the sense of pain without loss of consciousness – a synonym for analgesic.

In New Zealand, Kimberley Maxwell from NIWA has been investigating the use of sea cucumbers for waste disposer as way to reduce organic waste in aquaculture systems. The polyculture of sea cucumbers could provide aquaculturists with a lucrative added revenue stream – sea cucumbers can command up to $NZ15 (approx $US10) per kg dry weight.

The CSIRO in Australia have been working to ensure the sustainable harvest of sea cucumbers to prevent overfishing while allowing Torres Strait Islanders to benefit from the use of sea cucumber stocks. This is a traditional harvest, according to wikipedia:

To supply the markets of Southern China, Macassan trepangers traded with the Indigenous Australians of Arnhem Land. This Macassan contact with Australia is the first recorded example of trade between the inhabitants of the Australian continent and their Asian neighbours.