Fresh Baits Research Articles

Reproductive biology of Diopatra neapolitana (Annelida, Onuphidae), an exploited natural resource in Ria de Aveiro (Northwestern Portugal)

AbstractDiopatra neapolitana Delle Chiaje, 1841 (Annelida, Onuphidae) is an important economic natural resource in Ria de Aveiro (northwestern coast of Portugal) and throughout Europe. The species is intensively harvested for use as fresh bait. However, there is only limited knowledge about its life cycle derived from a previous study in Mediterranean Sea. Reproduction and development patterns are known to vary biogeographically, making it important to base management decisions on locally appropriate information. This work examines reproduction patterns for populations from the Eastern Atlantic, which have not previously been assessed, with an eye towards drawing Atlantic–Mediterranean comparisons and informing local management strategies. The study was conducted from May 2007 to April 2009 in Ria de Aveiro. The reproductive biology of D. neapolitana was described from the proportional variation of worms with gametes in the coelom and from the progression of the oocyte diameter. Individuals with gametes inside the coelom were found all year round, but the peak reproductive period occurred between May and August, when almost all individuals had gametes in the coelom and females contained more oocytes than at any other time of the year. The overall male:female ratio was close to 1:1 and the oocyte diameter ranged from 40 to 240 μm. In vitro fertilization was performed and the results compared to other studies. Based on the present results, some protection measures are suggested to implement a sustainable exploitation of the species.

Effects of the bittering agent denatonium benzoate on the success of toxic baiting of pestiferous German wasps (Vespula germanica)

Our aim was to study the effects of the addition of varying concentrations of the bittering agent, denatonium benzoate (DB), to toxic baits used for the control of German wasps (Vespula germanica). We tested the level of detection of different concentrations of DB by wasps, and measured the overall effectiveness of freeze-dried baits containing 0.1% fipronil and DB to control local wasp activity. The addition of DB concentrations higher than 10 ppm to fresh beef baits made them less attractive to wasps compared with controls. Lyophilized toxic baits containing DB 10 ppm and fipronil 0.1% were as attractive as control baits and reduced local wasp abundance by, on average, 74%. The results for lyophilized baits containing 0.1% fipronil but lacking DB were similar (average reduction: 80%). The addition of DB to toxic baits against Vespula spp. can bring about undesirable effects on toxic baiting efficacy. In the case of V. germanica, we suggest using the lowest concentration possible (i.e. 10 ppm or lower) that may still elicit an aversive response in humans and/or non-target species.

Nocturnal Oviposition Behavior of Necrophagous Dipterans in Kelantan, Malaysia*

The likelihood of dipteran maggots colonizing a corpse due to nocturnal oviposition can be used to challenge the postmortem interval (PMI) estimated assuming diurnal oviposition. Earlier experiments tested nocturnal oviposition behavior by exposing fresh baits once during a single night. In this pilot study, oviposition behavior was studied using beef baits, which, simulating the decay of the body seen in case situations, decomposed inside cages designed to open and close at scheduled intervals during consecutive night or twilight periods. Freshly hatched maggots from diurnally oviposited eggs emerged in control baits on the third day, while a limited number of maggots attributable to nocturnal or twilight oviposition were observed in experimental baits only on the fifth or sixth day, indicating a categorical delay. These results suggest that such delayed and limited nocturnal oviposition is not forensically significant since the larger maggots deriving from diurnal oviposition would be the ones considered when estimating PMI.

Evaluation of commercial and field-expedient baited traps for house flies, Musca domestica L. (Diptera: Muscidae)

A comparison of nine commercial baited fly traps on Florida dairy farms demonstrated that Terminator traps collected significantly more (13,323/trap) house flies (Musca domestica L.) than the others tested. Final Flight, Fly Magnet, and FliesBeGone traps collected intermediate numbers of flies (834-2,166), and relatively few were caught with ISCA, Advantage, Fermone Big Boy, Squeeze & Snap, or OakStump traps (<300). Terminator traps collected about twice as many flies (799.8/trap) as FliesBeGone traps (343.8) when each trap was baited with its respective attractant, but when the attractants were switched between the two trap types, collections were significantly lower (77-108) than was observed with traps baited with their respective attractant. Solutions of molasses were significantly more attractive to house flies than honey, maple syrup, or jaggery (date palm sugar). Field-expedient traps constructed from discarded PET water bottles were much less effective than commercial traps, but painting the tops of such traps with black spray paint resulted in a six-fold increase in trap capture.

Do scientists and fishermen collect the same size fish? Possible implications for exposure assessment

Recreational and subsistence fishing plays a major role in the lives of many people, although most Americans obtain their fish from supermarkets or other commercial sources. Fish consumption has generally increased in recent years, largely because of the nutritional benefits. Recent concerns about contaminants in fish have prompted federal and state agencies to analyze fish (especially freshwater fish targeted by recreational anglers) for contaminants, such as mercury and polychlorinated biphenyls (PCBs), and to issue fish consumption advisories to help reduce the public health risks, where warranted. Scientists engaged in environmental sampling collect fish by a variety of means, and analyze the contaminants in those fish. Risk assessors use these levels as the basis for their advisories. Two assumptions of this methodology are that scientists collect the same size (and types) of fish that fishermen catch, and that, for some contaminants (such as methylmercury and PCBs), levels increase with the size and age of the fish. While many studies demonstrate a positive relationship between size and mercury levels in a wide range of different species of fish, the assumption that scientists collect the same size fish as fishermen has not been examined. The assumption that scientists collect the same size fish as those caught (and eaten) by recreationalists or subsistence fishermen is extremely important because contaminant levels are different in different size fish. In this article, we test the null hypothesis that there are no differences in the sizes of fish collected by Aleut fishermen, scientists (including divers), and commercial trawlers in the Bering Sea from Adak to Kiska. Aleut fishermen caught fish using rod-and-reel (fishing rods, hook, and fresh bait) from boats, as they would in their Aleutian villages. The scientists collected fish using rod-and-reel, as well as by scuba divers using spears up to 90 ft depths. A fisheries biologist collected fish from a research/commercial trawler operated under charter to the National Oceanographic and Atmospheric Administration (NOAA). The fish selected for sampling, including those caught commercially in the Bering Sea, represented different trophic levels, and are species regularly caught by Aleuts while fishing near their villages. Not all fish were caught by all three groups. There were no significant differences in length and weight for five species of fish caught by Aleuts, scientists, and fisheries trawls, and for an additional 3 species caught only by the Aleut and scientist teams. There were small, but significant, differences in the sizes of rock greenling ( Hexagrammos lagocephalus) and red Irish lord ( Hemilepidotus hemilepidotus) caught by the scientist and Aleut fishermen. No scientists caught rock greenling using poles; those speared by the divers were significantly smaller than those caught by the Aleuts. Further, there were no differences in the percent of males in the samples as a function of fishing method or type of fishermen, except for rockfish and red Irish lord. These data suggest that if scientists collect fish in the same manner as subsistence fishermen (in this case, using fishing rods from boats), they can collect the same-sized fish. The implications for exposure and risk assessment are that scientists should either engage subsistence and recreational fishermen to collect fish for analysis, or mimic their fishing methods to ensure that the fish collected are similar in size and weight to those being caught and consumed by these groups. Further, total length, standard length, and weight were highly correlated for all species of fish, suggesting that risk assessors could rely on recreational and commercial fishermen to measure total lengths for the purpose of correlating mercury levels with known size/mercury level relationships. Our data generally demonstrate that the scientists and trawlers can collect the same size fish as those caught by Aleuts, making contaminant analysis, and subsequent contaminant analysis, representative of the risks to fish consumers.

Feeding and Survivorship of Blueberry Maggot Flies (Diptera: Tephritidae) on Protein Baits Incorporated with Insecticides

Laboratory feeding trials evaluated fly survivorship on six insecticides (acetamiprid, clothianidin, deltamethrin, fipronil, imidacloprid, and spinosad) incorporated at 4, 40, and 400 ppm in protein baits. Higher concentrations of insecticides resulted in increased fly mortality. At all concentrations of insecticides in baits, except those on deltamethrin, there was a significantly higher mortality 4 d after the initial feeding, compared with flies that fed on a control bait. The presence of clothianidin or imidacloprid in baits led to significantly less feeding compared with a control bait without insecticide. There were no feeding deterrent effects of bait containing either fipronil or spinosad compared with a control bait without insecticide. Exposure of flies to fresh bait containing 40 ppm of acetamiprid, clothianidin, or imidacloprid, resulted in significantly more flies becoming knocked down than the control. Baits containing 40 ppm of fipronil or spinosad resulted in higher levels of fly mortality than baits containing either neonicotinoids (acetamiprid, clothianidin, or imidacloprid) or no insecticide for trials with fresh and 1-d-old bait with unlimited exposure. At the rates tested baits containing deltamethrin resulted in no fly knockdown and always had the lowest mortality of any insecticide treatment. The tradeoffs between insecticides capable of knockdown and mortality are discussed as they relate to management of R. mendax.

Estimation of the Diopatra neapolitana annual harvest resulting from digging activity in Canal de Mira, Ria de Aveiro

Bait digging for recreational and commercial fishing is widely practiced and economically significant. Since polychaetes often form part of the diets of several demersal species they are commonly used as fresh bait by sports and professional fishermen. The objectives of this paper are to quantify the annual bait digging of harvest Diopatra neapolitana in the intertidal mudflats of Canal de Mira, Ria de Aveiro, Portugal and comment briefly on its significance for management. Annual harvest, defined as D. neapolitana (kg) caught by collectors, was calculated as the product of independent estimates of harvesting effort using a progressive count and harvest rate through an access survey. Harvesting effort was higher during spring tides in all seasons except in winter and harvest rate lower during winter, regardless of tidal range, and higher during spring tides. Bait collection in the Canal de Mira is very intense with an annual harvest in excess of 45,000 kg per year valued at over € 325,000 per year. Management of the remove needs to take account of both the ecosystem impacts of bait digging and the socio-economic importance of bait digging to the many families involved.

Effects of Aging and Dilution on Attraction and Toxicity of GF-120 Fruit Fly Bait Spray for Melon Fly Control in Hawaii

Attractiveness and toxicity of GF-120 Fruit Fly Bait (Dow AgroScience Indianapolis, IN) to melon flies, Bactrocera cucurbitae Coquillett, were examined to assess the effects of concentration and aging. We tested dilutions of 20, 40, and 80 ppm (AI) (spinosad) against water controls. The 80 and 40 ppm treatments were significantly more attractive than the 20 ppm and control treatments. Attraction was compared between baits aged for 2 and 24 h, fresh bait and water controls. Age had significant effects on both attractiveness and toxicity of GF-120. Baits aged for 2 h were 11 times less attractive to female melon flies than fresh bait. Mortality rates were reduced by 50% when GF-120 was subjected to rain. Our results suggest the need for frequent applications of GF-120 to obtain maximum benefits, particularly in wet tropical climates.

Feeding and foraging of wild and sterile Mediterranean fruit flies (Diptera: Tephritidae) in the presence of spinosad bait.

The sterile insect technique (SIT) is used to control wild Mediterranean fruit fly introductions in California and Florida in the U.S. In the past, bait sprays containing malathion proved invaluable in treating new outbreaks or large populations before the use of SIT. Recently, a spinosad protein bait spray, GF-120, has been developed as a possible alternative to malathion, the standard insecticide in protein bait sprays. In this study, protein-deficient and protein-fed Vienna-7 (sterile, mass-reared, "male-only" strain) flies and wild males and females were evaluated to determine the effectiveness of the GF-120 protein bait containing spinosad with respect to bait attraction, feeding, and toxicology. There were no effects of diet or fly type on feeding duration in small laboratory cages. Wild flies, however, registered more feeding events than Vienna-7 males. Flies that fed longer on fresh bait died faster. Protein-deficient flies were more active and found the bait more often than protein-fed flies. Data suggest that adding protein to the diet of SIT flies may decrease their response to baits, therefore, reduce mortality, and thus, allow the concurrent use of SIT and bait sprays in a management or eradication program.

Attraction and feeding responses of Mediterranean fruit fly and a natural enemy to protein baits laced with two novel toxins, phloxine B and spinosada

AbstractStudies were conducted to determine attraction and feeding propensity of Mediterranean fruit fly, Ceratitis capitata (Wiedemann), to different protein bait mixtures with and without the insecticides malathion, spinosad, and phloxine B. Protein baits were more attractive to females than to males. Protein‐starved females responded more than protein‐fed females. The type of protein (USB® yeast hydrolysate enzymatic, Mazoferm®E802, Nu‐Lure®Insect Bait, or Provesta® 621 autolyzed yeast extract) in the bait had a major influence on C. capitata attraction, which was strongest to fresh Provesta. Aged baits (four day‐old) were not as attractive as fresh baits. In feeding propensity studies, highest response was observed for USB protein. On the basis of attraction and feeding responses Provesta (attraction and feeding) and USB (feeding) outperformed the standard Nu‐Lure. Protein‐starved flies were much more likely to feed on protein compared to protein‐fed flies. For protein‐starved flies, a mixture of Provesta and malathion repelled fruit flies, compared to a mixture of Provesta and spinosad or phloxine B. This was not the case with protein–fed flies. The wasp Fopius arisanus (Sonan), one of C. capitata's primary natural enemies in Hawaii, would not consume protein baits. Our studies suggest that spinosad or phloxine B, with low contact toxicity, mixed with protein baits offers a more environmentally friendly choice for control of C. capitata and conservation of F. arisanus, whereby the nontarget effects of broad spectrum contact poisons such as malathion can be avoided. Presumably, due to greater selectivity with spinosad and phloxine B bait treatments, the host would be killed, but not the natural enemy.

Effect of lengthy storage on the palatability and efficacy of zinc phosphide wheat bait used for controlling house mice

The palatability and efficacy of 2.5% zinc phosphide (ZP) wheat bait that had been in dry storage for about 3.5 years was tested against house mice in canola crops in the central wheatbelt region of Western Australia. Before baiting, mouse numbers in these crops were around 90 mice ha-1. Mouse numbers were reduced by 89% in the crop where the stored bait was applied at 1 kg ha-1 by aerial broadcast. The palatability of the stored bait was also determined in additional crops by comparing the amount taken with that of `fresh' ZP wheat bait. Bait (200 g) was offered in two different types of bait station: (1) in 45-cm lengths of 50-mm-diameter plastic agricultural drainage pipe, and (2) on 40-cm-diameter plastic saucers. Regardless of station type, mice often consumed significantly more of the stored product than the `fresh' bait, particularly on Day 1. This was attributed to the stored product lacking the typical, strong ZP odour that was initially present in the fresh bait. Mouse numbers on the bait station grids (1.28 ha each) were reduced by approximately 65% after 4 days of baiting. The shelf-life and palatability of ZP wheat bait seem to be relatively unaffected by prolonged storage. If any decrease in palatability occurs, then this seems to be transient and did not reduce the overall effectiveness of the stored bait.

Seabird By-Catch in Small-Scale Longline Fisheries in Northern Peru

-Longlining has been encouraged in Peru as an opportunity for small-scale fishermen to reduce cetacean mortality in gill nets. Very little is known about seabird by-catch in this longline fishery. In January 1999, we conducted surveys in five fishing villages in northern Peru to estimate seabird by-catch and 29 fishermen were interviewed. Eighty percent of the fishermen used frozen bait, which increases the probability of seabird mortality. Ninety percent of fishermen confirmed that birds are hooked while setting the gear. Additionally, we found that over 40% of hooked seabirds were albatrosses. The most common albatross off northern Peru is the Waved Albatross (Phoebastria irrorata) and about 60% of the population of the Chatham Island Albatross (Thalassarche eremita) winters off Peru. Both species are considered threatened due to their small population sizes. Seabird by-catch in the Peruvian small-scale longline fishery should be of conservation concern; pooled estimates of by-catch rates based on interviews were 1 to 2 birds/1,000 hooks. The estimated by-catch of albatrosses by the entire fleet is likely to lie between 2,370 and 5,610 birds each year, which represents between 5% and 13% of the pooled populations of the Waved and Chatham Island Albatrosses. Even though these numbers are extrapolations, they can be considered a rough indicator of the magnitude of the seabird by-catch by the small-scale longline fishery in Peru. Further research that includes onboard seabird by-catch surveys as well as a larger sample of interviews with fishermen are required. Public awareness that encourages the implementation of by-catch deterrence measures such as bird lines, night setting of hooks, and the use of fresh bait, will help reduce by-catch and bait loss, thus benefiting fishermen and promoting albatross conservation. Received 10 July, accepted 28 September 2000.

Study on biological and ecological characteristics ofIps subelongatus Motsch

Ips subelongatus Motschulsky were raised indoors and in the field using fresh baits for study of biological and ecological characteristics during 1992-1994. The life cycle of the pest in Lishu County, Jilin Province was described. The study results indicated that temperature was a main factor affecting the development of Ips subelongatus. The initial temperature for development of egg, larva, pupa and adult was 6.1, 8.0, 10.3 and 9.8℃, respectively. To complete one-generation needs, respectively, 48 d at temperature of 18℃, 39 d at 20℃ and 33 d at 22℃. The pest has different number of generations in different area as a result of temperature change. In Jilin Province, it generally has three generations, except that some individuals have 2 generations. The nature enemies for this pest are Thanasinus substriatus, Tomimicobia seitneri Ruschk, Coeliodes sp. etc.

Using Track Plates and Remote Cameras to Detect Marten and Short-Tailed Weasels in Coastal Cedar Hemlock Forests

We studied the distribution of American marten (Martes americana) and short- tailed weasels (Mustela erminea anguinae) on northern Vancouver Island, British Columbia, over 2 winters from 1996 to 1998. We tested a combination of track plates and remote cameras to detect marten and weasels in 4 broadly different habitats: early seral cut-blocks, regenerating cut-blocks, old forests, and grassy edge habitats. We measured vegetation structure at many sample sites in order to describe habitats where marten and weasels were detected. We detected similar numbers of marten in all of the low elevation forest stands sampled; fewer marten were detected in grassy edge habitats than in forested stands. Weasels were detected at sites with open forest and little structure compared to forested stands. Weasels were detected primarily in edge habitats associated with forest openings or riparian areas dominated by grass ground cover. We used rotten bait and lure, instead of fresh bait, to make sites most attractive to marten and weasels. We used 7-day checks which allowed us to trap more sites than shorter check in- tervals. Track plate boxes worked well for detecting marten and weasels though we suggest extending the roof and sides at both ends of the box 20 cm beyond the floor to provide greater protection from rain. Cameras were expensive, heavy, and failed to detect marten more often than track plates. We suggest that cameras be used only to identify unknown tracks or early in a study to determine appropriate methods.

Attraction of the sheep blowfly, Lucilia sericata (Diptera: Calliphoridae) to carrion bait in the field

AbstractThe facultative ectoparasite, Lucilia sericata (Meigen) has been described as a pioneer colonizer of carrion. This behaviour is believed to enable it to escape the intense interspecific competition which can occur between dipterous larvae within carrion. Such escape is necessary as this fly species has been thought to have reduced competitive ability, resulting from its evolutionary progression towards parasitism. In the work reported here, the attraction of L. sericata to carrion bait at different stages of decomposition (fresh to 28 days old) was investigated in the field. Trials were run over three years, with carrion bait presented in the presence and absence of sodium sulphide. Decomposition had a significant effect on the numbers of L. sericata caught; more decomposed bait caught greater numbers of L. sericata than fresh bait. However, this effect was not apparent if sodium sulphide was added to the carrion. With sodium sulphide added, there was no significant difference in the attraction of female L. sericata, regardless of bait age. There was no general relationship between carrion bait age and the number of female L. sericata caught in different stages of ovarian development. The present data, therefore, suggest that L. sericata does not act exclusively as a pioneer species. Furthermore, this work suggests that, if used with sodium sulphide, the stage of carrion bait decomposition does not significantly modify carrion bait attractiveness.

異なる餌料で養成したマダイ体成分の比較

Proximate, fatty acid, and free amino acid compositions in the muscle of cultured red sea bream fed moist pellet (MP-fish) were compared with those of the fish fed fresh bait (FB-fish). Lipid accumulation in the abdominal cavity of both fish was also examined.The lipid content in the muscle of MP-fish was almost the same as that of FB-fish. On the other hand, the content of lipid in the abdominal cavity of MP-fish was higher than that in FB-fish. In the fatty acid composition of muscle non-polar lipid, the percentages of C18:1 n-9 and C18:2 n-6 in MP-fish were higher than in FB-fish, while the percentage of C22:6 n-3 was lower in the former than in the latter. Fatty acid composition of muscle non-polar lipid was affected by the bait.Free amino acid composition was also affected by the bait. The content of Anserine in MP-fish was higher than that in FB-fish, while the contents of Lys, His, and Arg were much lower.

Corn Steepwater as Protein Bait for Anastrepha suspensa (Diptera: Tephritidae)

Field trials were conducted to determine the potential use of corn steepwater, an acid-hydrolyzed corn product, as a liquid bait for the Caribbean fruit fly, Anastrepha suspensa (Loew), in Florida. Preference tests compared relative attractiveness among aqueous solutions of standard torula yeast plus sodium borate pellets or 10% steepwater (vol:vol) plus 1, 3, 5, and 10% (wt:vol) borax in traps. Total number of females trapped decreased from 474 in fresh bait solution to 197 and 154 in 2–3-d old and 4–6-d old bait solutions, respectively. When freshly prepared solutions were tested, the torula yeast-borax solution was the most attractive and the 10% steepwater with 1% borax the second most attractive bait formulation, capturing 45 and 23% of the trapped females, respectively. After 2–3 d of field-use, there was less discrimination among the baits, although the 10% steepwater with 1% borax and with 10% borax each captured 29% of the trapped flies. By the last 4–6 d of field use, the 10% steepwater with 1% borax was most preferred and captured 45% of the trapped flies. Dissections of subsamples of trapped females indicated that only 50% of the females from tortula yeast-borax traps were unmated, while 80–95% of the females caught in any of the steepwater traps were unmated. The addition of 1, 3, 5, and 10% borax increased the initial pH of the acidic steepwater to 5.95, 7.76, 8.44, and 8.76, respectively. The relative attractiveness of the 10% steepwater with 1% borax increased as this bait approached a neutral pH over the 6 d of field use.

Effects of bait age on the number, sex, and age composition of Lucilia cuprina (Wiedemann) (Diptera: Calliphoridae) in Western Australian blowfly traps

Daily catches of the Australian sheep blowfly, Lucilia cuprina, in Western Australian blowfly traps were not significantly affected by exposing the baits in traps for up to 3 days in the field before trapping. Exposure of the baits for longer periods significantly increased the daily catch totals of both sexes. Baits with a mean exposure time before trapping of 7 days (old baits) returned significantly higher catches than baits with a zero exposure time (fresh baits): 5-fold and 3-fold increases, respectively, for males and females. Exposure of baits for only 1 day was sufficient to produce significant changes in the reproductive age composition of female catches; proportions of newly emerged females increased and proportions of gravid females decreased. Coefficients of variation for old bait/new bait catch ratios were small, 16.4% for males and 12.3% for females, which confirmed that both baits exhibited consistent levels of attractiveness on different trapping dates. Procedures are suggested for estimating population densities of L. cuprina based on trap catches using fresh and old baits.

Field trials of slow‐release synthetic lures for stoats(Mustela erminea)and ferrets(M. furo)

Abstract Experimental field trials were used to compare the attractiveness to stoats (Mustela erminea) and ferrets (M. furo) of traps set with either a synthetic scent lure or with fresh food bait. One lure, containing 2‐n‐propylthietane, effectively attracted as many ferrets as did rabbit meat bait. Fewer stoats were caught with this lure than with egg bait. Made up in a slow‐release formulation in “plastic rope”, the lure remained attractive to ferrets for at least 2 weeks under sunny field conditions. Traps containing a second lure, 3‐n‐propyl‐l,2‐dithiolane, were less successful at catching both mustelid species than those containing fresh food baits. The scent lures were not attractive to non‐target species, but neither did they deter some species.

The importance of chemical stimuli in bait fishing — fishing trials with presoaked bait

The importance of chemical stimuli in longlining was investigated by comparing the catching power of baits soaked in sea water prior to baiting with that of fresh bait in fishing trials for torsk ( Brosme brosme). Mackerel baits presoaked for 2, 4 and 24 h gave 87%, 84% and 50% of the catch rate of fresh bait, respectively. The results are discussed in relation to data on temporal change in release rate of feeding attractants from bait and the sensitivity of the chemical senses in fish. It is concluded that for bottom set longlines, high release rate of attractants is of great importance to attract fish to the gear, whereas fish present close to the gear during setting may also respond to the baited hooks by visual stimuli.