Significant Differences In Catch Research Articles

A systematic review and meta-analysis on the efficacy of internal spermatic artery ligation during laparoscopic varicocelectomy in children and adolescents: Is it safe?

Challenges in identifying small testicular arteries and lack of microscopic experience have led to a rising trend in the use of laparoscopic technique for pediatric and adolescent varicocele. The controversy over artery ligation (AL) and artery preservation (AP) during laparoscopic varicocelectomy (LV) is still debatable. This study investigates the effectiveness of AL and AP during LV in pediatric and adolescent varicocele cases. The systematic searches based on PRISMA guideline were conducted in PubMed, Scopus, ScienceDirect, Web of Science and ProQuest databases with pre-defined keywords. Both quantitative and qualitative analyses were performed to assess catch-up growth, persistence, recurrence, hydrocele, operative time, post-operative testicular volume, and sperm analysis. A total of 1512 patients from 9 eligible studies were included. There were no significant differences in catch up growth (OR 0.89; 95%CI 0.53, 1.51; p = 0.68) or hydrocele incidence (OR 0.59; 95%CI 0.28, 1.24; p = 0.16). The recurrence rate and persistence rate in AP group is significantly higher compared to AL group (OR 2.95; 95%CI 1.53, 5.68; p = 0.001 and OR 5.13; 95% CI 2.04, 12.88; p = 0.0005, respectively). The mean operative time during laparoscopic varicocelectomy is significantly longer when arteries are preserved as opposed to when they are ligated (OR 5.33; 95%CI 2.05, 8.60; p = 0.001). AL and AP both improved testicular volume and post-operative sperm analysis. AL showed higher efficacy and comparable safety to AP. We recommend using AL with lymphatic sparing to minimize hydrocele complications.

Characteristics of fish community structure and environmental driving factors in Taihu Lake during the first year of fishing ban.

Taihu Lake has officially implemented the full fishing ban policy since October 1, 2020. We investigated fish community of Taihu Lake in the four seasons of 2020. A total of 42 fish species were collected, belonging to 6 orders, 7 families, and 33 genera. The first five dominant species ranked by the index of relative importance were Coilia nasus, Toxabramis swinhonis, Hypophthalmichthys molitrix, Hypophthalmichthys nobilis, and Salangichthys tangkahkeii. The number of C. nasus accounted for 85.1% of the total number of catches. According to the distributional characteristics of cyanobacterial blooms and aquatic plants, Taihu Lake could be divided into the northern, central, and eastern regions. There was no significant difference in catch per unit effort (CPUE) among different lake regions, but Shannon diversity index and Pielou evenness index in the eastern region was greater than in the other two regions. The CPUE, Shannon diversity index, and Pielou evenness index were significantly different among the four seasons, with the lowest CPUE in autumn and higher diversity in autumn and winter than in spring and summer. Electrical conductivity, water depth, chloride, and transparency were the main environmental factors driving the seasonal variations of fish community in Taihu Lake, while electrical conductivity, dissolved oxygen, total alkalinity, and transparency were key variables driving the spatial patterns. The results could be used as the baseline data for fish community studies in Taihu Lake after the fishing ban.

Evaluating dolphin damage in trammel net fisheries in the Valencia region: Insights to improve management

Interactions between dolphins and trammel net fisheries have been described in the Mediterranean Sea as having negative consequences for both cetaceans and fishers. There is a need for studies that evaluate the economic costs caused by dolphins feeding from entangled fishes in trammel nets since most cetacean species involved in these interactions are endangered. This study aims to evaluate the economic impact of the interaction between dolphins and trammel nets fisheries in the coastal waters of the Valencian region in the western Mediterranean Sea. We conducted at-port visual inspections of nets from April 2018 to March 2019, which included 1,849 fishing operations with trammel nets, and we recorded damages to the net and catch and the value of the fishery. Thirty-two interactions were detected during the year of the study. The only observed species interacting was the common bottlenose dolphin. No bycatch of dolphins was reported. The interactions have been impacted seasonally and most of them took place in February and March. There were no significant differences in catch when comparing sets with and without depredation or damage in nets due to depredation by dolphins. Also on average, no differences were found in the value of the catch when comparing sets with or without damage caused by dolphins. The main cost to the fisher was the cost of repairing the nets. The estimated financial loss per vessel and year was €556 (95%CI: €303–€809). This represents less than 1% of the total yearly income of each vessel in our area. We suggest implementing tools to economically compensate artisanal vessels for any damage caused by dolphins in order to avoid increasing the hostile feeling of fishers towards dolphins and to apply conservation measures to protect this cetacean species.

An ecological assessment of large coastal shark communities in South Florida

Given population declines of many shark species, coupled with increasing conservation efforts and recoveries, there is a need for baseline assessments and continued monitoring of shark populations to support management. The waters of South Florida, USA, are used by a diverse array of sharks that occur among a mosaic of habitats and management zones. Here we conducted standardized drumline surveys from Miami through the middle Florida Keys to examine spatial, seasonal and environmental patterns in shark occurrence, catch per unit effort, composition, and demographic structure. Between 2009 and 2021, a total of 21,755 drumlines were deployed, capturing 3398 sharks, comprising fifteen species. Ginglymostoma cirratum, (n = 1335), Carcharhinus limbatus, (n = 650), Negaprion brevirostris, (n = 314), C. leucas, (n = 253), and Sphyrna mokarran, (n = 238) were the most common species encountered. Overall, the largest shark surveyed was a 450 cm S. mokarran and the smallest shark was a 50 cm Rhizoprionodon terraenovae. At the assemblage level, relative abundance among regions and seasons were generally similar; however clear species-specific patterns of abundance, size structure, and sex-composition were detected by season, region, habitat, and management zones. Of the physical conditions evaluated, habitat type and depth emerged as the most influential parameters affecting abundances and sizes of species captured. While few species exhibited significant differences in catches by management zone, areas with the most restrictive fisheries regulations generally supported higher abundances for which differences were detected. These data serve as a baseline for future monitoring of shark populations in South Florida and assessing their response to environmental change.

Sex-specific vulnerability of Portunus armatus to capture in round traps with traditional and novel fish baits

In response to few data describing the effects of bait on trap efficiencies for blue swimmer crabs, Portunus armatus in an Australian fishery and an impetus to reduce costs, traditional baits (sea mullet, Mugil cephalus and luderick, Girella tricuspidata) were compared against a novel, less-expensive bait (European carp, Cyprinus carpio). Eight replicate traps with each bait type were fished over four days at one location in the fishery for a total of 96 trap lifts. Traps baited with sea mullet caught significantly more (by >1.5×) total blue swimmer crabs and at a greater net-profit trap deployment–1 (>3.7×) than traps with the other two baits, which produced similar catches and profits. But, the superior performance of sea mullet as bait was due to greater catches of female blue swimmer crabs (which were larger and are more valuable owing to ovarian development), with no significant difference in catches of males among bait types. Such sex specificity was attributed to possible divergent, temporal nutritional requirements including a dietary bias among mature females preparing to migrate to oceanic areas prior to reproduction. Additional data are required across larger spatio-temporal scales to further elucidate patterns; however there are clear implications for fishers that seek to maximise catches of females in the studied fishery or potentially minimise female catches which are prohibited in other Australian fisheries. Further, it is also clear that sex-specific catch data acquired during surveys should be considered for possible confounding effects of bait (and other technical factors) prior to extrapolating relative abundances.

Combining plant volatiles and pheromones to catch two insect pests in the same trap: Examples from two berry crops

Most horticultural crops are attacked by more than one insect pest. As broad-spectrum chemical control options are becoming increasingly restricted, there is a need to develop novel control methods. Semiochemical attractants are available for three important horticultural pests, strawberry blossom weevil, Anthonomus rubi Herbst (Coleoptera: Curculionidae), European tarnished plant bug, Lygus rugulipennis Poppius (Hemiptera: Miridae) and raspberry beetle, Byturus tomentosus deGeer (Coleoptera: Byturidae). Traps targeting more than one pest species would be more practical and economical for both monitoring and mass trapping than traps for single-species. In this study we aimed to (1) improve the effectiveness of existing traps for insect pests in strawberry and raspberry crops by increasing catches of each species, and (2) test if attractants for two unrelated pest species could be combined to capture both in the same trap without decreasing the total catches. Field tests were carried out in four European countries and different combinations of semiochemicals were compared. A volatile from strawberry flowers, 1,4 dimethoxybenzene (DMB), increased the attractiveness of the aggregation pheromone to both sexes of A. rubi. The host-plant volatile, phenylacetaldehyde (PAA), increased the attraction of female L. rugulipennis to the sex pheromone, and, in strawberry, there was some evidence that adding DMB increased catches further. Traps baited with the aggregation pheromone of A. rubi, DMB, the sex pheromone of L. rugulipennis and PAA attracted both target species to the same trap with no significant difference in catches compared to those single-species traps. In raspberry, catches in traps baited with a combination of A. rubi aggregation pheromone, DMB and the commercially available lure for B. tomentosus, based on raspberry flower volatiles, were similar to those in single-species traps. In both crops the efficiency of the traps still needs improvement, but the multi-species traps are adequate for monitoring and should not lead to confusion for the user as the target species are easy to distinguish from each other.

Effects of 2D seismic on the snow crab fishery

Abstract Sound is used by a variety of marine taxa for feeding, reproduction, navigation and predator avoidance and therefore alterations to the soundscape from industrial noise have the potential to negatively affect an animal’s fitness. Furthermore, responses to industrial noise would also have the potential to negatively influence commercial fishing interests. Unfortunately marine invertebrates are generally underrepresented in the seismic effects literature. Snow crab harvesters in Atlantic Canada contend that seismic noise from widespread hydrocarbon exploration has strong negative effects on catch rates. We repeated a Before-After-Control-Impact study over two years to assess the effects of industry scale seismic exposure on catch rates of snow crab along the continental slope of the Grand Banks of Newfoundland. Our results did not support the contention that seismic activity negatively affects catch rates in shorter term (i.e. within days) or longer time frames (weeks). However, significant differences in catches were observed across study areas and years. While the inherent variability of the CPUE data limited the statistical power of this study, our results do suggest that if seismic effects on snow crab harvests do exist, they are smaller than changes related to natural spatial and temporal variation.

Pest behaviour insights from quarantine surveillance of male Queensland fruit fly, Bactrocera tryoni (Froggatt) (Diptera: Tephritidae)

Fruit flies (Diptera: Tephritidae) are a major problem for Australia's $6.9 billion horticultural industry. Bactrocera tryoni (Froggatt) is the most significant fruit fly pest in the eastern states of Australia. Catches of male B. tryoni from cuelure-baited Lynfield surveillance traps in towns bordering the Fruit Fly Exclusion Zone in New South Wales, Australia, from November to May in 2001/2002–2007/2008 were analysed with respect to year, town, property type (urban/rural), and tree species/crop varieties in which the trap was placed (tree type). Average catches of all traps were highest in 2007/2008 and lowest in 2003/2004, and showed an overall positive correlation with rainfall (P < 0.05). More B. tryoni males were caught in Wagga Wagga and Lockhart than in other towns. There were no significant differences in catches of B. tryoni between urban and rurally located traps. With respect to tree type, traps placed in pomefruit trees caught significantly more flies than those in citrus, stonefruit, or nonfruit trees, with no significant differences among the latter three tree groups. Within the pomefruit group, traps in apples (Malus domestica Borkh.) and pears (Pyrus spp.) caught significantly more flies than those in cotoneasters (Cotoneaster spp). Within the citrus group, traps in orange trees (Citrus × sinensis (L.) Osbeck) caught significantly more flies than those in mandarin trees (Citrus reticulata Blanco). No significant differences were detected in catches between any members of the stonefruit group. Within the nonfruit group, traps placed in kurrajongs (Brachychiton populneum (Schott & Endl.) R. Br.) caught significantly more flies than those placed on other tree species in the group. This study demonstrates that although surveillance programs conducted to establish and/or maintain area freedom from specific pests may not provide balanced datasets, careful analysis of the results of such programs can provide valuable insights into the behaviour of the species in question.

Effects of 16/0 Circle Hooks on Pelagic Fish Catches in Three South Pacific Albacore Longline Fisheries

The present study tested the effects of using large 16/0 circle hooks on catch rates in three pelagic longline fisheries in the south pacific ocean. large (16/0) circle hooks were tested against a variety of smaller hooks already in use by longline vessels in american samoa, cook islands, and new caledonia. The majority of these fleets use a mix of hook sizes, including circle hooks that are smaller than a 16/0 circle hook. Vessels alternated hooks throughout every set, maintaining a 1:1 ratio of 16/0 circle hooks to their existing hooks. information on catch by hook size, fish lengths, and condition at gear retrieval was collected. in total, 4912 fishes of 33 species were observed on 145,982 hooks from 67 sets. in the cook islands fishery, there was no significant difference in catch by hook type for two main target species, but there was an increase in catchability for swordfish, Xiphias gladius (linnaeus, 1758). in the new caledonia fishery, there was no significant difference in catch by hook size for any species. in the american samoa fishery, 16/0 circle hooks did not significantly affect the catch of albacore, Thunnus alalunga (bonnaterre, 1788), but did significantly reduce the catch of skipjack tuna, Katsuwonus pelamis (linnaeus, 1758), dolphinfish, Coryphaena hippurus (linnaeus, 1758), and wahoo, Acanthocybium solandri (cuvier, 1832). for all locations, catch rates on 16/0 circle hooks were nominally lower, but not always significant for smaller pelagic species.

Catch Rates with Variable Strength Circle Hooks in the Hawaii-Based Tuna Longline Fishery

The hawaii-based deep-set longline fleet targets bigeye tuna [Thunnus obesus (lowe, 1839)] and infrequently takes false killer whales [fkw,Pseudorca crassidens (owen, 1846)] as bycatch. from 2004 to 2008 with 20%-26% observer coverage, nine mortalities of and serious injuries to fkw were documented in the deep-set fishery in the hawaii eeZ, yielding a mean take estimate of 7.3 animals yr-1. weak hook technology can utilize the size disparity between target and other species to promote the release of larger non-target species. four vessels tested the catch efficacy and size selectivity of 15/0 �strong� circle hooks (4.5 mm wire diameter) that straighten at 138 kg of pull in comparison with 15/0 �weak� (4.0 mm) that straighten at 93 kg of pull. vessels alternated hook types throughout the longline gear and maintained a 1:1 ratio of strong and weak hooks. observers monitored a total of 127 sets of 302,738 hooks, and randomization tests were applied to test for significant differences in catch for 22 species. There were no significant catch differences for bigeye tuna; however, there may be limitations to these inferences because trials were not conducted during spring when larger bigeye tuna are available to the fishery. There were no significant differences in mean length of 15 species. observers collected 76 straightened hooks, of which six were control and 70 were weak hooks. There was one observation of a fkw released from a stronger circle hook. overall, there was no statistical reduction in catch rates of bycatch species.

Quantity of food attractant and size of the container orifice affect catch in Carpophilus spp. traps

AbstractAttract‐and‐kill traps containing aggregation pheromone and food attractant have been developed in Australia to control Carpophilus spp. (Coleoptera: Nitidulidae) in orchards. Two field experiments were conducted in cherry and stone fruit orchards. One aimed to identify an appropriate size of orifice in co‐attractant containers releasing either of two types of food attractants while keeping the amount of attractant fixed. Initial findings suggested that a 6.0 cm orifice was appropriate so another experiment was conducted to identify an appropriate amount of food attractant to be used in traps while keeping the size of orifice fixed at 6.0 cm. In experiment one, orifice sizes of 2.5 cm, 6.0 cm and 9.0 cm were used in traps baited with 120 mL of either fermented apple juice or liquid synthetic food attractant. Traps with a 6.0 cm orifice caught the most Carpophilus spp. followed by 9.0 cm and 2.5 cm but there were no significant differences in catch between the three orifice sizes. In experiment two, traps were baited with 120, 300 and 500 g or mL of either solid artificial beetle‐rearing medium or liquid synthetic food attractant. Traps baited with synthetic solutions caught significantly (P &lt; 0.05) more beetles than traps baited with solid food medium except for the 500 g solid food traps. There were no significant differences in catch between the three amounts of synthetic solution. Traps with 500 g of solid food medium caught significantly (P &lt; 0.05) more beetles than those with 300 g and 120 g.

A quarter of a century succession of epigaeic beetle assemblages in remnant habitats in an urbanized matrix (Coleoptera, Carabidae)

We studied the long-term (23–24 years) species turnover and succession of epigaeic beetle assemblages (Coleoptera: Carabidae, incl. Cicindelinae) in three remnant habitats [cottonwood (Populus spp.) and oak (Quercus spp.) stands, and old fields] that are embedded within highly urbanized areas in central Minnesota. A total of 9,710 beetle individuals belonging to 98 species were caught in three sampling years: 1980, 1981 and 2005 in pitfall traps in identical locations within each habitat. Results indicate that there were 2–3 times greater trap catches in 2005 than in 1980 (cottonwood and oak stands, and old fields) and 1.4–1.7 times greater species diversity of beetles in 2005 than in the 1980-1981 suggesting increased habitat association by beetles over time. Although there were no significant differences in catches between 2005 and 1981 (only cottonwood stands and old fields), there was a trend where more beetles were caught in 2005. At the species-level, 10 times more of an open-habitat carabid species, Cyclotrachelus sodalis sodalis LeConte, was caught in 2005 than in 1980. However, trap catches of five other abundant carabid species [Pterostichus novus Straneo, Platynus decentis (Say), Platynus mutus (Say), Calathus gregarius (Say), and Poecilus lucublandus lucublandus (Say)] did not change indicating population stability of some beetle species. These remnant habitats were increasingly colonized by exotic carabid species as Carabus granulatus granulatus Linneaus, Clivina fossor (Linneaus) and Platynus melanarius (Illiger), that were trapped for the first time in 2005. Species composition of epigaeic beetles was quite distinct in 2005 from 1980 with 39 species reported for the first time in 2005, indicating a high turnover of assemblages. At the habitat-level, greatest species diversity was in cottonwood stands and lowest was in old fields, and all habitat types in 2005 diverged from those in 1980s, but not cottonwood stands in 1981. As our sampled areas are among some of the last remnants of the original oak savanna habitats in central Minnesota, we hypothesize that conservation of these sites may be critical to maintaining epigaeic beetle assemblages under increased urbanization pressure.

Temporal and spatial distribution of fish and shrimp assemblage in the Bakkhali river estuary of Bangladesh in relation to some water quality parameters

Fish and shrimp species, together with water quality data, were collected from two different stations located inside the Bakkhali river estuary of Bangladesh during winter, premonsoon and monsoon periods. Significant temporal differences were observed for water temperature, salinity and dissolved oxygen. The average catch of fish and shrimps per net between stations varied between 1.89±0.36kg at station 1 and 7.54±4.39kg at station 2, while the average catch in winter, premonsoon and monsoon periods found to be 2.79±1.08kg/net, 6.31±1.03kg/net and 5.06±2.89kg/net, respectively, with a significant difference in catch per net between stations although no significant difference in catch per net was observed between seasons. A total of 18,467 individuals of fish (35 species) and shrimp (10 species) were found in the present study. Three species of shrimps were observed to be dominant (>10.0%) and these were Metapenaeus lysianassa (17.07%), Ambassis dussumieri (14.54%) and Macrobrachium villosimanus (12.13%). Clear differences in faunal abundances were observed between seasons and stations with higher mean abundances during winter (1747.83±421.99 individual/5kg) and at Station 1 (1444±866.74 individuals/5kg). Similarly, the diversity indices, both Shannon–Wiener and Margalef, showed significant differences between stations and seasons (except Shannon for stations). Analyses of similarity (ANOSIM) results confirm both spatial and temporal differences in species community structure with a highly diverse assemblage. Canonical Correspondence Analysis results indicated that salinity and transparency were the main variables influencing fish and shrimp distribution in the Bakkhali river estuary.

Assessing the Reliability of Fisher Self‐Sampling Programs

AbstractThe transition to catch share management for groundfish fisheries in the waters off the northeastern USA will require more monitoring than is presently obtained through traditional programs. Other types of at‐sea reporting may be necessary to address data gaps and complement other sampling programs like the Northeast Fisheries Observer Program (NEFOP). Validation of fisher self‐sampling programs, such as the study fleet program of the School for Marine Science and Technology (University of Massachusetts Dartmouth), provides another monitoring option to be used in conjunction with existing systems. In this paper, data from the study fleet program were compared with other fisheries‐dependent data sources in the region. We tested for significant differences in catch at the trip, species, and haul levels by disposition (i.e., kept and discarded). Effort and length measurements for six commercial species were also analyzed. Catch results were mixed but similar for commercial species across comparisons. The study fleet program and NEFOP had consistent reporting in comparison with dealer landings, which are reported to the National Marine Fisheries Service by seafood dealers that are issued a federal permit to sell fish. For comparisons of catch at the haul level, there was a significant difference between NEFOP data and study fleet data; median differences were small, and the study fleet reported less catch. For commercial species, there was no significant difference in catch (except for kept catch) between the study fleet data and NEFOP data. Study fleet catch data were more comprehensive than logbook data (e.g., study fleet data included catch of bycatch species). Effort data from the study fleet were more accurate and precise than logbook data and were similar to NEFOP data. There was no statistical difference in length frequencies based on study fleet data and NEFOP data.Received April 16, 2010; accepted November 26, 2010

Improved interspecific selectivity of nylon shrimp (Heterocarpus reedi) trawling in Chile

In order to improve the inter-specific selectivity of a new bottom trawl design for demersal crustaceans, an experimental attempt was carried out to compare the shrinkage effect in length of net structure accessories, particularly shorter bridles and sweeps, based on previous studies on escape behavior of gadiform fishes. For this purposes, an experimental fishing for nylon shrimp ( Heterocarpus reedi ) was carried out on board of two trawler vessels. The results showed no significant differences in catch per unit of fishing effort (CPUE) for the target species between gears and significant reductions (p < 0.05) for the most important bycatch species ( Merluccius gayi ) with the modified gear. In fact, the average CPUE for M. gayi decreased 5.6 kg h -1 (19.2%) and 35.7 kg h -1 (47.5%) for each vessel.

A comparison of catch rates of artificial lures from an automated handline fishery at Shetland, UK

Automated handlining (jig fishing) has recently been trialled in waters around Shetland, UK. Although different types and colours of artificial lures are commercially available there is a paucity of information available on the effects of either lure design or lure colour on resulting catches. We compared the catch rates of (1) five colours of rubber eel tube lures; and (2) five different designs of artificial lure commonly used in handline fisheries. Lure colour did not significantly affect catches of pollack ( Pollachius pollachius), saithe ( Pollachius virens), cod ( Gadus morhua), ling ( Molva molva) or tusk ( Brosme brosme). Cod showed a preference for lower hooks on the six hooks per reel set-up when lures were black and pollack showed a preference for lower hooks when the lures were blue. There were no significant differences in catches of saithe, cod, ling or tusk between the five lure types. However, catches of pollack on a novel ‘sonar’ lure were lower than on other lures. No evidence of a preference for any hook position on the reels was found with any of the lure types.

On the Apparently Striking Disconnect between Motivation and Satisfaction in Recreational Fishing: The Case of Catch Orientation of German Anglers

AbstractIn this study, three distinct segments of German anglers differing with respect to degree of catch orientation as the main fishing motive were identified in a nationwide telephone survey (N = 474). Noncatch aspects of the fishing experience played a major role in the motivations of anglers: about 80% of the sample was classified as anglers with a low, or minimal, catch orientation. Angler satisfaction and its determinants were examined across degrees of catch orientation to improve understanding of the link between angler motivation and satisfaction. Highly catch‐oriented anglers were significantly less satisfied with the previous angling season than were minimally catch‐oriented anglers. An exclusivity of activity‐specific, mainly catch‐related, satisfaction components as predictors of overall angling year satisfaction was found in all angler segments, irrespective of catch orientation. Satisfaction was unrelated to actual catch or harvest rates, and no significant differences in catch and harvest were found across the three catch orientation groups. This suggested that catch expectation was the primary driver of angler satisfaction. This study revealed that there are anglers, most often the majority within the population, who can be characterized as attaching relatively little importance to catch motives but whose satisfaction is still mainly catch dependent. It is not warranted to conclude that there is a striking disconnect in this finding. The reasons for the apparently striking inconsistency between motivation and satisfaction are related to (1) the fundamental conceptual differences in meaning and definition of motivation and satisfaction and (2) the differential ease in satisfying activity‐general and activity‐specific aspects of the fishing experience. Care must be taken not to draw overly simplified management implications from motivational information. However, by knowing the determinants of angler satisfaction, the manager's ability to plan future management actions is improved, and satisfaction rather than motivation is the ultimate product of the fishing experience.

Coral‐reef sounds enable nocturnal navigation by some reef‐fish larvae in some places and at some times

At Lizard Island, Great Barrier Reef, catches of fish larvae by light traps that broadcast nocturnal reef sounds (noisy traps) were compared with catches by quiet traps over two 2·5 week new‐moon periods in November (XI) 2000 and January (I) 2001. Three areas were sampled: near‐reef (NR, 500 m from the shore) in I, middle (M, 650 m) in I and XI and offshore (O, &gt;1000 m) in XI. The most abundant taxa captured were Apogonidae, Blenniidae, Chaetodontidae, Lethrinidae, Mullidae and Pomacentridae. Significant differences in catch were found between areas, and a position effect was found at the O and M areas. At the NR and M areas, no taxa had significantly greater catches in quiet traps, but larvae of five taxa had significantly greater catches in noisy traps. These were (areas and times of greater catches): Apogonidae (NR; M XI), Mullidae (M I &amp; XI), Pomacentridae (NR; M I &amp; XI), Serranidae (M I) and Sphyraenidae (NR). At the offshore area, five taxa (Apogonidae, Blenniidae, Chaetodontidae, Mullidae and Pomacentridae) had significantly greater catches in quiet traps and only Lethrinidae had significantly greater catches in noisy traps. Thus some taxa (particularly apogonids and pomacentrids which had catches up to 155% greater in noisy traps, but also lethrinids and mullids, and perhaps others), were attracted to reef sounds at night, but this apparently varied with location and time. The sound‐enhanced catches imply a radius of attraction of the sound 1·02–1·6 times that of the light. More than 65 m from the speaker,the broadcast sound levels at frequencies typical of fish hearing were equivalent to background levels, providing a maximum radius of sound attraction in this experiment.

Monitoring the recreational gamefish fishery off south-eastern Australia

The east coast Australian gamefish fishery is a diverse, multi-species fishery that targets billfish, sharks, tuna and other pelagic fish along the east Australian seaboard. A Gamefish Tournament Monitoring Program (GTMP) was undertaken, and 39021 angler trips from 1996 to 2000 were analysed. The program reports on trends in fishing effort, catch rates, catch composition, proportions of captures tagged and released and spatial distribution of catches for the principal recreational billfish species: black marlin (Makaira indica), striped marlin (Tetrapterus audax) and blue marlin (Makiara nigricans).The GTMP was principally designed as part of an integrated program to monitor the recreational gamefish fishery. The spatial and temporal design of the program restricted statistical analyses however, there were trends in fishing effort, directed effort, catch rates, catch composition, proportions of fish tagged and spatial distribution of catches for the principal recreational billfish species over seven successive years (1994–2000). Analysis of catch data, stratified by directed effort, indicated significant differences in catches of target species, demonstrating the importance of calculating catch rate estimates according to the main target preference. Analysis of tournament based tagging information indicated that while overall tournament tagging rates remained high (88%) there were significant differences in the number of fish tagged between species groups highlighting the impact that angler attitude and the competition point score structure has on the harvest of gamefish target species.

Minor components in the sex pheromone of legume podborer: Maruca vitrata development of an attractive blend.

The legume podborer, Maruca vitrata (syn. M. testulalis) (F.) (Lepidoptera: Pyralidae) is a pantropical pest of legume crops. Sex pheromone was collected by gland extraction or trapping of volatiles from virgin female moths originating in India, West Africa, or Taiwan. Analysis by GC-EAG and GC-MS confirmed previously published findings that (E,E)-10,12-hexadecadienal is the most abundant EAG-active component with 2-5% of (E,E)-10,12-hexadecadienol also present. At least one other EAG response was detected at retention times typical of monounsaturated hexadecenals or tetradecenyl acetates, but neither could be detected by GC-MS. Laboratory wind-tunnel bioassays and a field bioassay of blends of (E,E)-10,12-hexadecadienal with (E,E )-10,12-hexadecadienol and a range of monounsaturated hexadecenal and tetradecenyl acetate isomers indicated greatest attraction of males was to those including (E,E)-10,12-hexadecadienol and (E)-10-hexadecenal as minor components. In subsequent trapping experiments in cowpea fields in Benin, traps baited with a three-component blend of (E,E)-10,12-hexadecadienal and these two minor components in a 100:5:5 ratio caught significantly more males than traps baited with the major component alone, either two-component blend, or virgin female moths. Further blend optimization experiments did not produce a more attractive blend. No significant differences in catches were found between traps baited with polyethylene vials or rubber septa, or between lures containing 0.01 and 0.1 mg of synthetic pheromone. Significant numbers of female M. vitrata moths, up to 50% of total catches, were trapped with synthetic blends but not with virgin females. At present there is no clear explanation for this almost unprecedented finding, but the phenomenon may improve the predictive power of traps for population monitoring.