Panel Discussion - Management of Eurasian watermilfoil in the United States using native insects: State regulatory and management issues

While researchers have evaluated the potential of native insect herbivores to manage nonindigenous aquatic plant species such as Eurasian watermilfoil ( Myriophyllum spicatum L.), the practical matters of regulatory compliance and implementation have been neglected. A panel of aquatic nuisance species program managers from three state natural resource management agencies (Minnesota, Vermont and Washington) discussed their regulatory and policy concerns. In addition, one ecological consultant attempting to market one of the native insects to manage Eurasian watermilfoil added his perspective on the special challenges of distributing a native biological control agent for management of Eurasian watermilfoil.

Aquatic insects as target organisms for the study of effects of projected climate change in the British Isles

One of the objectives of the Terrestrial Initiative in Global Environmental Research is to assess the sensitivity of British plant and animal species to climate change. The first phase of the program involved the identification of criteria for selecting species suitable for the study of effects of projected climate change in the British Isles. Apart from shallow ponds, annual temperature ranges of 0 to 25 C in temperate freshwater habitats are narrower than those in most temperate terrestrial habitats. Although freshwater organisms have to exist within a narrower range than their terrestrial equivalents, few species can survive throughout their life cycle over the whole temperature range. Field studies on the effects of natural and artificial thermal discharges into streams and rivers have shown that increases in water temperature affect aquatic insects at both the species and community level. Although field data provide valuable information, a more productive approach is to determine experimentally the requirements of different species. Although there are just over 1850 species of aquatic insects in the British Isles, detailed quantitative information on the relationship between temperature and development of eggs, larvae and pupa is available for relatively few species. One exception is the egg stage of stoneflies (Plecoptera). The range for egg hatching in stoneflies clearly show that some species could be threatened while others could benefit from a defined increase in water temperature as a result of climate change. A critical review of the available data on this group would produce a set of equations that could be used to predict the ecological effects of climate change on this group of indicator species.

Aquatic insects as target organisms for the study of effects of projected climate change in the British Isles

The chief objectives of this brief review are to collate and synthesise quantitative information on the temperature requirements of aquatic insects, and to identify species, and groups of species, that could be useful indicators of climate change and predictors of the ecological effects of change. It arose from the first phase of the Terrestrial Initiative in Global Environmental Research (TIGER), a five-year, NERC Community Programme on the role of the terrestrial biosphere in the science of global change. This phase involved the identification of criteria for selecting species suitable for the study of effects of projected climate change in the British Isles. Field and laboratory studies are reviewed, and criteria for selection of species for future research are suggested. The literature survey shows that no species of aquatic insect can be found to meet all three criteria, but information on the British stoneflies and their eggs already satisfies two of them.

Effects of a flash-flood on channel morphology and some insects of a small stony stream in the Peak District, Derbyshire

In this paper, some observations are made following a flash-flood that occurred in Stake Clough, a small tributary of the River Goyt, during the evening of 6 August 1996. The site was visited eight times between 8 August - 30 October 1996 to take samples and make observations on the stream. The flood scoured the bed of Stake Clough but more significantly, caused it to change course along the middle part of the floodplain. Initially after the flood, the numbers of insects in all stretches of the stream channel were low (100-200 m super(2)), but then gradually rose to population densities approaching ten times this figure. The benthos was dominated by the Chironomidae and also leuctrid stoneflies (Leuctra nigra, L. hippopus and L. inermis). On 8th August 1996, 12 mesh bags, each containing oak leaves, were placed in the stream and collected after 24 hours. These were also dominated by chironomids, and contained relatively high numbers of the caddis, Potamophylax cingulatus.

Results of the Austrian-Ceylonese hydrobiological mission 1970 of the 1st Zoological Institute of the University of Vienna (Austria) and the Department of Zoology of the University of Ceylon Vidyalankara Campus, Kelaniya. Pt. 13. Some remarkable ripicol insects of the Ceylonese fauna

New Ceylonese records namely, Euscelimena gavialis (Sauss.), Paranemobius pictus Sauss. and semiaquatic cockroaches of the genus Rhabdoblatta were found in the collection of Saltatorid and Dictyopterid insects.

Evaluation of SP1001 (Pelargonic Acid) in Combination with Glyphosate on Cattail and Alligatorweed

Cattail (Typha latifolia L.) is a common and troublesome weed in shallow, freshwater environments throughout the United States. Alligatorweed (Alternanthera philoxeroides (Mart.)Griseb.), in spite of the introduction and success of several insects as biological controls, remains a troublesome we4ed in a a number of locations in the Southeast where there are frequent human disturbances (e.g., insecticide spraying, mechaniceal removal, etc.) and/or weather conditions that affect the life cycle of the insects (Kay1992, Vogt et al. 1992). Both of these weeds routinely are managed by foliar applications of the herbicide, glyphosate [N-(phosphonomethyl)glycine]. Regrowth and reinfestation of previously treated areas usually necessitates additional herbicide application during subsequent years. A new product that could enhance the activity of glyphosate on these weeds would be useful in their management. In 1997, SePRO Corp. initiated t4esting of an experimental compound, SP1001, to determine its efficacy either as a herbicide or as an adjuvant to boost the activity of glyphosate for use in aquatic sites. The objective of this study was to evaluate the potential for using SP1001 as an adjuvant to replace surfactants customarily used during application of glyphosate for control of cattail and alligatorweed.

Biological survey of the Panama Canal Zone (1912)

At first it was intended to confine the collections to the Canal Zone proper, but as the faunal and floral areas extended to the north and south of this region, it was decided to carry the work into the Republic of Panama, a step which met with the hearty approval of that Republic. The work accomplished has been very valuable to science, including collections and observations of vertebrate animals, land and fresh water mollusks, and plants, including flowering plants, grasses and ferns. Special attention will be given during the coming season to vertebrate animals, insects, crustaceans, rotifers and other minute freshwater animals, and also to the microscopic plants known as diatoms. Includes appendix of papers that resulted.

Length-weight relationship and the diets of Clarias lazera (Cuvier and Valenciennes), family Clariidae (Osteichthyes: Siluriformes) in Zaria, Nigeria

The length-weight relationship and the diets of Clarias lazera were investigated between July 1981 and June 1982. About 450 specimens were examined. The standard lengths of the fish ranged from 8.5 cm to 42.2 cm. Significant differences were found between the standard lengths of the males and females with the latter slightly shorter. Somatic weights varied between 10 g to 502 g. Length-weight regression analysis gave a "b" value of 3.02 for both males and females combined; thus indicating an isometric growth. Analysis of the food in the stomachs showed that the fish is an omnivore although, it fed more on insects and fish than other food items

Present status and potentials of inshore and offshore pelagic fisheries in the capture and processing industries of Nigeria

Apart from activities of some foreign-based vessels, commercial exploitation of pelagic fishery resources in Nigeria has been limited to inland and inshore waters. Estimated potential for the inshore pelagic fishery is 70,000-90,000 tonnes while the small pelagic resources in the near offshore as well as tuna and tuna-like fishes further offshore have potentials of about 10,000 metric tonnes each. Despite the abundance of tuna within and adjoining the Nigerian EEZ, and its importance in the international market, only foreign-flagged vessels take advantage. In addition, the inshore pelagic fisheries in Nigeria have for long remained underexploited. The most common processing method has remained the age-old traditional smoke-drying, which is inadequate resulting in colossal waste through denaturation and incessant infestations by insects and moulds among other causes. The use of modern smoking techniques coupled with effective distribution systems can undoubtedly reduce waste. However, these are often not within the reach of most artisanal processors. It is proposed that the organised private sector should invest on simple but proven processing equipment such as smoking kilns. The inshore pelagic fish species and other small fishes can sustain cottage canning industries sited in fishing villages/settlements while larger canning factories should be based on offshore resources. Modalities for successful investments are highlighted, while a major consideration is given to joint ventures

Observations on the ecology of Hepsetus odoe, Bloch, 1794 (Pisces: Hepsetidae) in Epie Creek floodplain, Niger Delta, Nigeria

The distribution, abundance, age and growth, the food and feeding habits, condition factor and reproduction of Hepsetus odoe in the Epie Creek Floodplain (Nigeria) was studied. H. odoe occur in the creek, swamp channel and lake. It is a very common, abundant and one of the major commercial species. A total of 457 specimens weighing 76.90 kg were caught during the period of investigation. The catches were more abundant in the dry season than in the wet season. The total length ranged from 10 cm to 46 cm while the weight varied between 50 g and 900 g. Six distinct components or year classes were observed using Bhattacharya's method. A growth exponential value 'b' was 3.35 with condition factor, 'k' values ranging from 0.69 to 0.83. The main diets of Hepsetus odoe were fish, including crustaceans (shrimps) and insects. The mean fecundity was 6060 plus or minus 358 eggs (range 2,769 to 6.667 eggs). The ova diameter of H. odoe was found to range from 2.2 mm to 2.6 mm with overall mean = 2.4 plus or minus 0.1)

Food composition and digestive enzymes in the gut of the African electric catfish Malapterurus electricus (Gmelin 1789) (Malapteruridae)

Analyses of stomach contents of 330 Malapterurus electricus (standard length, 10.1-30.5 cm) in Mahin Lagoon (southwestern Nigeria) established it as a bottom feeder. There was a preponderance of insects accounting for >80% occurrence and >25% of total volume in stomachs of specimens, suggesting a stenophagous predatory habit. Qualitative and quantitative assays of digestive enzymes in the different regions of the gut (oesophagus, stomach, duodenum, ileum, rectum) were investigated. Carbohydrases (amylase, maltase), chitinase, proteases (pepsin, chymotrypsin, trypsin) and lipases were detected in different gut regions with different activity. The pattern of distribution and relative activity of the enzymes correlated with the predatory diet

Control of insect infestation in smoked West African sardines Sardinella maderensis 'Sawa' using actellic 50 EC solution

Fish which has been cured or are in the process of being cured by traditional methods are usually infested by insects, posing a real problem to traders and processors, especially in Nigeria. The effects of 0.03% actellic 50 EC solution and vegetable oil on insect infestion were studied using West African sardines, Sardinella maderensis. Actellic solution was more effective in combating insect infestation than vegetable oil. Appearance and perceived smoked fish flavour of fish treated with Actellic and vegetable oil differed (P<0.05), while taste was unaffected by treatment. Actellic 50 EC solution though effective, could be subject to abuse