An Estuarine Low Temperature Fish Kill in Mississippi, with Remarks on Restricted Necropsies

In January 1973, large numbers of Mugil cephalus (striped mullet), weighing approximately 250 gm each, died in two freshwater localities in tidewater bayous of Jackson County, Mississippi. Fish identified as Mugil curema, M. cephalus, Megalops atlantica, Dormitator maculatus, and Fundulus grandis were found dead in other low saline estuarine areas. Fish-kills during cold periods are less commonly encountered in Mississippi than in Texas or Florida. This particular incident is attributed to conditions of stress for fishes incompletely acclimated to the encountered low temperatures. The most deleterious stress was the low saline water which probably allowed a breakdown in the fishes' ion-osmoregulatory mechanisms. Striped mullet and other euryhaline fishes in salinities greater than 6 ppt survived, as did freshwater centrarchids and ictalurids in areas with dying mullet. Other stresses thought to contribute to the weakening of striped mullet in Paige Bayou during the period of rapidly decreasing temperatures include starvation and high levels of pesticide residues. In examined fish, the alimentary tracts were devoid of food, the gall bladders were distended and leaking bile, the livers contained excess lipid material and were often stained throughout with bile pigments, and the levels of DDT metabolites and endrin residues in the liver were higher than in control fish. Stress caused by low levels of dissolved oxygen, toxic substances in the water, or disease was discounted as a cause of death.

A review of diseases associated with cage culture systems: diagnosis and control in smale scale fish farming

Fish cage culture is a rapid aquacultural practice of producing fish with more yield compared to traditional pond culture. Several species cultured by this method include Cyprinus carpio, Orechromis niloticus, Sarotherodon galilaeus, Tilapia zilli, Clarias lazera, C. gariepinus, Heterobranchus bidorsalis, Citharinus citharus, Distochodus rostratus and Alestes dentes. However, the culture of fish in cages has some problems that are due to mechanical defects of the cage or diseases due to infection. The mechanical problems which may lead to clogged net, toxicity and easy access by predators depend on defects associated with various types of nets which include fold sieve cloth net, wire net, polypropylene net, nylon, galvanized and welded net. The diseases problems are of two types namely introduced diseases due to parasites. The introduced parasites include Crustaseans, Ergasilus sp. Argulus africana, and Lamprolegna sp, Helminth, Diplostomulum tregnna: Protozoan, Trichodina sp, Myxosoma sp, Myxobolus sp. the second disease problems are inherent diseases aggravated by the very rich nutrient environment in cages for rapid bacterial, saprophytic fungi, and phytoplanktonic bloom resulting in clogging of net, stagnation of water and low biological oxygen demand (BOD). The consequence is fish kill, prevalence of gill rot and dropsy conditions. Recommendations on routine cage hygiene, diagnosis and control procedures to reduce fish mortality are highlighted

First Report of a Toxic Nodularia spumigena (Nostocales/Cyanobacteria) Bloom in Sub-Tropical Australia. II. Bioaccumulation of Nodularin in Isolated Populations of Mullet (Mugilidae)

Fish collected after a mass mortality at an artificial lake in south-east Queensland, Australia, were examined for the presence of nodularin as the lake had earlier been affected by a Nodularia bloom. Methanol extracts of muscle, liver, peritoneal and stomach contents were analysed by HPLC and tandem mass spectrometry; histological examination was conducted on livers from captured mullet. Livers of sea mullet (Mugil cephalus) involved in the fish kill contained high concentrations of nodularin (median 43.6 mg/kg, range 40.8-47.8 mg/kg dry weight; n = 3) and the toxin was also present in muscle tissue (median 44.0 mu g/kg, range 32.3-56.8 mu g/kg dry weight). Livers of fish occupying higher trophic levels accumulated much lower concentrations. Mullet captured from the lake 10 months later were also found to have high hepatic nodularin levels. DNA sequencing of mullet specimens revealed two species inhabiting the study lake: M. cephalus and an unidentified mugilid. The two mullet species appear to differ in their exposure and/or uptake of nodularin, with M. cephalus demonstrating higher tissue concentrations. The feeding ecology of mullet would appear to explain the unusual capacity of these fish to concentrate nodularin in their livers; these findings may have public health implications for mullet fisheries and aquaculture production where toxic cyanobacteria blooms affect source waters. This report incorporates a systematic review of the literature on nodularin measured in edible fish, shellfish and crustaceans.

Characteristics and causes of Texas marine strandings

Three major mass mortality events occurred on the upper Texas coast during 1994, from January through the second week of May. These events were distinguished by unusually large numbers of dead dolphins, sea turtles, and fishes washing ashore on Texas beaches. The beach stranding of dead animals began in January with bottlenose dolphins. By the end of March, 142 dolphins had washed ashore as compared to about 40 expected. By the latter part of April, dolphin mortalities declined but stranding of dead and comatose sea turtles increased. By the end of April, at least 127 sea turtles had stranded on the Texas coast since the beginning of the year, about double the expected number. Then, during May and June, a third mortality event began with a massive fish kill and more turtle deaths. By the middle of May, mortalities of all species as indicated by beach strandings returned to within expected levels. Nevertheless, 1994 stood out as a record year of marine mass mortalities in the northwestern Gulf of Mexico. (PDF file contains 94 pages.)

South & West Cumberland Fisheries Advisory Committee 3rd June, 1974

This is the first report from the South and West Cumberland Fisheries Advisory Committee meeting, which was held on the 3rd June 1974. The report includes sections on fishery byelaws, estimates for the anticipated income and expenditure on fisheries for the current year, and fish mortality. The section on fish mortality includes the details of a fish kill on the River Marron, gives points along the river where water was sampled, and the results of the analysis. The Fisheries Advisory Committee was part of the Regional Water Authorities, in this case the North West Water Authority. This preceded the Environment Agency which came into existence in 1996.

South & West Cumberland Fisheries Advisory Committee 17th October, 1977

This is the report from the South & West Cumberland Fisheries Advisory Committee meeting, which was held on the 17th October, 1977. It covers fisheries income and expenditure, licence duties, and information on the River Marron at Lostrigg Beck in connection with opencast coal workings in the area. It also looks at the proposal for the development of the Eskett Quarries and the likely effect on the River Ehen, and the possible development of Rivers Waver and Wampool as a sea trout fishery. The report for that covers the physical descriptions of the catchments, abstractions, discharges, biological aspects, chemical aspects and the present situation regarding fisheries. Also included is the report by the area fisheries officer on fisheries activities which includes information on river improvement works on the River Calder, Branthwaite Weir Fish Pass, a fish kill on the tributary of the River Calder, stock numbers, and an update on Holmwrangle hatchery. The Fisheries Advisory Committee was part of the Regional Water Authorities, in this case the North West Water Authority. This preceded the Environment Agency which came into existence in 1996.

Widespread occurrence of the jellyfish Pelagia noctiluca in Irish coastal and shelf waters

An oceanic cruise (October 2007) revealed the widespread occurrence of Pelagia noctiluca in the NE Atlantic just prior to a major fish kill induced by P. noctiluca in Irish coastal waters.

Recent changes to the biogeochemistry of Muchalat Inlet, B.C., and the implications for HABs

Senior thesis written for Oceanography 445

Fisheries bycatch data provide insights into the distribution of the mauve stinger (Pelagia noctiluca) around Ireland

There is concern that jellyfish populations are proliferating in the Northeast Atlantic and that their socio-economic impacts will increase. Using information from the Irish Groundfish Survey, data are presented on the distribution of the mauve stinger, Pelagia noctiluca, over an area >160 000 km² around Ireland and the UK in 2009. The species accounted for 93% of the overall catch of gelatinous organisms, with an average catch biomass of 0.26 ± 2.3 kg ha−1. The study area was divided into four subregions (North, West, Southwest, and South), and the distribution and abundance of P. noctiluca displayed both inter- and intraregional variations. Individual bell diameters ranged from 1 to 13.5 cm (median 4.5 cm, s.d. 1.2 cm), and the size distribution also varied spatially. It is the first time that such detailed information has been made available for P. noctiluca in a part of the Northeast Atlantic where its impact on the salmon aquaculture industry can be considerable. Finally, the possibility of using annual datasets from this type of fisheries survey to develop time-series that, in the future, will allow investigation of relationships between long-term variations of P. noctiluca populations and climatic factors in the area is addressed.

Mídia impressa e meio ambiente: um estudo da cobertura da mortandade de peixes no estuário do Rio Potengi, Natal-RN

Environmental issues are becoming increasingly habitual to the media, particularly when calamities are involved. A feature of environmental disasters is that they disclose both environmental crises and the media limitation in reporting them. The research tried to contribute to the subject through the study of press media coverage of a large fish kill along an estuary in the State of Rio Grande do Norte, Brazil, in 2007. Thematic content analysis of newspaper reports identified the predominance of a superficial and denunciative coverage, lacking an educational perspective, and with little contribution to formation of a critical sense in readers. It also has identified the precarious treatment of those scientific concepts that could substantiate the actual causes of mortality of tons of aquatic fauna

Fish stupefying plants used by the Gond tribal of Mendha village of Central India

Fish stupefying plants and their methods of use by the Gond people of Mendha village of the Gadchiroli district in Maharashtra state have been documented. For the purpose of validation, literature survey revels that many fish stupefying plants being used since long time by local people are recently well tested by many workers and are found to have many important medicinal properties. It was also observed that herbal fish stupefying agents are excellent means of fishing, which do not kill whole fish stock like chemicals.

Removal of Sea Lettuce, Ulva spp., in Estuaries to Improve the Environments for Invertebrates, Fish, Wading Birds, and Eelgrass, Zostera marina

Mats (biomasses) of macroalgae, i.e. Ulva spp., Enteromorpha spp., Graciolaria spp., and Cladophora spp., have increased markedly over the past 50 years, and they cover much larger areas than they once did in many estuaries of the world. The increases are due to large inputs of pollutants, mainly nitrates. During the warm months, the mats lie loosely on shallow sand and mud flats mostly along shorelines. Ulva lactuca overwinters as buds attached to shells and stones, and in the spring it grows as thalli (leaf fronds). Mats eventually form that are several thalli thick. Few macroinvertebrates grow on the upper surfaces of their thalli due to toxins they produce, and few can survive beneath them. The fish, crabs, and wading birds that once used the flats to feed on the macroinvertebrates are denied these feeding grounds. The mats also grow over and kill mollusks and eelgrass, Zostera marina. An experiment was undertaken which showed that two removals of U. lactuca in a summer from a shallow flat in an estuarine cove maintained the bottom almost free of it.