Relationships between Stocking and Anglers' Catches in Draycote Water Trout Fishery

The trout fishery at Draycote Water was investigated during the 1980 fishing season. Fish stocked were batch-marked according to the date of introduction by freeze branding, and catch data were obtained by the cooperation of anglers. Population estimates were made at the end of the fishing season using gill nets and mark-recapture techniques. Of the 32,960 marked brown and rainbow trout stocked, 69.8% were caught and declared by anglers. Returns of rainbow trout were better (78.1%) than those of brown trout (44.2%). Over 90% of all fish caught were taken within 45 days of stocking. Catch per unit effort fluctuated widely but was closely associated with stockings of fish. Catchability (Q) of stocked fish was found to diminish rapidly with time after stocking. At the end of the fishing season the estimated population of marked trout was 4045 (2 × SE = 250), compared with a theoretical number (stock less total catch) of 10,802, giving a mean daily apparent natural mortality, made up of the true natural mortality plus the undeclared catch, of 1.36%.     

Benefits of repeated stocking with adult,hatchery‐reared brown trout,Salmo trutta,to recreational fisheries?

Abstract  Recaptures of adult, hatchery-reared, brown trout, Salmo trutta L., and fishing time from anglers were used to evaluate the benefits of stocking programmes with repeated releases of adult brown trout. The recapture rate varied between 17% and 29%. The time between stocking and capture (referred to as residence time) varied between 1 and 160 days (median 3–49 days). Between 67% and 84% of trout caught in the river were recently released fish. Fishing effort increased after stocking, thereby increasing the impact of angling on wild stocks. Stocking with adult brown trout decreases the impact of angling on wild trout only if the time spent fishing by all anglers is kept stable. Furthermore, because of the short residence time of stocked trout, long-term impacts through competition for space and food, or genetic impact through introgression, are limited.     

Performance of rainbow trout, Salmo gairdneri Richardson, in a put-and-take fishery, and influence of anglers' behaviour on catchability

Abstract. Stock, catch and fishing effort statistics for a 12·5-ha lowland pul-and-lake trout fishery have been used to compute the ‘catchability’ of rainbow trout, Salmo gairdneri Richardson, during the fishing seasons 1980–1983. Seasonal trends in the fishes’ susceptibility to capture by fly-fishing are apparent but there was no indication that, in this fishery, newly stocked fish were more vulnerable than the longer-term residents. This consistency of recapture rates of rainbow trout, relative to the population available, is a function both of the fish's behaviour and that of the anglers themselves, and it is suggested that for management purposes the latter must be taken into account. In the fishery studied rainbow trout grew well at fish densities below 60 kg ha^?1, but even with overall recapture levels exceeding 80% the yield of the fishery was less than the weight of fish stocked. The selection of strains of rainbow trout which satisfy the requirements of sport fisheries is discussed.     

Influence of stock levels, fishing effort and environmental factors on anglers' catches of Atlantic salmon, Salmo salar L., and sea trout, Salmo trutta L.

Abstract. Monthly catches of Atlantic salmon, Salmosalar L., and sea trout, Salmo trutta L., by anglers in a west of Ireland fishery were analysed. Data were available for 50 months from the years 1971 to 1981. The most important single determinant of catch was found to be fishing effort measured in boat-days. An additional 10 boat days were found to correspond to a catch of almost 6 salmon and 23 sea trout. The relationship between catch and stock was weaker, though a relatively high catchability of sea trout at low stock levels was recorded. Slock levels, fishing effort and environmental factors accounted for much, but not all, of the variation in catch from month to month and from year to year. Most of the effect of rainfall, sunshine and water level was attributable to variations in fishing effort associated with these factors.     

An analysis of angling returns for trout, Salmo trutta L., in a Scottish river

Abstract. Analysis of 4 years’ club records shows that, on average, the anglers fishing for brown trout in the lower River Don, Aberdeenshire, Scotland made 9 trips/y of 4 hours duration, caught 0·8 fish/trip at the rate of 0·2 fish/h, making a total of 7 fish/season, having an average weight of 350g. There was, however, considerable variation in the results. Guests tended to fish for longer, and to catch less, than regular members. Most (95%) of the fish were caught by only 30% of the anglers, who accounted for 80% of the fishing effort. Angler efficiency increased with the number of seasons spent fishing the club waters during the period; it decreased with increase in water temperature and flow and, early in the season, tended to decrease slightly with increase in catch in the preceding month.     

An Analysis of the Put-and-Take Trout Fishery at Toft Newton Reservoir

The operation of a put-and-take trout fishery at Toft Newton reservoir is analysed from detailed studies of the 1978 and 1979 seasons. Toft Newton is only a small reservoir but the large number of anglers that utilize the fishery mean that the stocking rates per hectare of water have to be very high. As a result of these high densities and a short average residence time in the reservoir, rainbow trout which were the predominantly stocked species do not grow after release. Brown trout, however, which were stocked at lower densities do grow after release. The success rate of the 8–9% of anglers not returning their catch data was examined using a postal survey. Partial correlation analysis indicated that the numbers of fish in the reservoir, the number of anglers fishing and the number of hours of sunshine significantly affected the catch rate. A regression between catch rate and number of fish in the reservoir only explained 35% of the variability but the addition of the other two factors did not significantly improve the accuracy of the model. The market area of the fishery was studied from the register of anglers. Most anglers attending Toft Newton travel a considerable distance to the fishery, the peak number driving from 98–129 km (61–80 miles) round trip. The present and future management policy of the fishery is discussed in the light of this analysis and many of the recommendations may also apply to other small put-and-take trout fisheries.     

Effect of hook type and hook setting method on deep-hooking rates when bait fishing for trout in lentic waters

Fishing with circle hooks along with prescribed hook-setting methods can reduce deep-hooking rates in some fisheries, but baited circle hooks have not been evaluated in stillwater trout fisheries. Deep-hooking rates and catch probabilities were compared for cutthroat trout Oncorhynchus clarkii​ (Richardson), rainbow trout Oncorhyncus mykiss (Walbaum), cutthroat × rainbow trout hybrids, and brook trout Salvelinus fontinalis (MItchill) caught using three types of baited hooks (circle, intermediate circle and traditional J) and two hook-setting methods (active and passive) in several lakes containing naturally reared trout. Hook type had a negligible effect on deep-hooking rates, which averaged 20%. Actively setting the hook and fishing with a bobber both reduced deep-hooking rates, regardless of hook type. Larger fish were deeply hooked more frequently regardless of hook type. Catch probabilities were higher when active rather than passive hook-setting was used, particularly in combination with intermediate circle hooks. The present results, which indicate that circle hook use did not reduce deep hooking in lentic settings, contrast earlier studies done in lotic waters. Therefore, before proposing hook-type regulations intended to reduce deep hooking, fisheries managers should consider waterbody type in addition to fishing methods, fish size and species.     

Analysis of Fishery Records from Cow Green Reservoir, Upper Teesdale, 1971–1980

Apart from some irregularities reflecting changes in permit costs (1975) and the effects of drought (1976), there were increases in angler-visits, catch per angler-visit and number of fish caught during the first 5 years of the fishery. Thereafter, there were about 1000–1500 angler-visits per season, a mean catch of 1.0–1.2 trout per angler-visit and an annual catch of 1200–1800 trout. Between 1971 and 1980 the mean weight of the fish caught fell from 472 to 349 g. During the period 1976–1980 the mean catch per angler-visit was 1.2 fish. This compares favourably with results from a selection of upland and lowland British reservoirs. The mean weight of individual trout caught was 362 kg and this value is typical of both stocked and unstocked upland reservoirs. The mean annual catch during 1976–1980 was about 2 kg ha^?1. This is similar to the values observed in other unstocked upland reservoirs. The gross yield from such reservoirs can be increased by stocking but the limited data available suggest that at stocking rates above about 5 kg ha^?1 the net yield (i.e. weight caught — weight stocked) becomes negative.     

Examining changes in participation in recreational fisheries in England and Wales

Abstract Inland fisheries in England and Wales have high economic and social values. Managing participation to maximise fishery performance is key to maintaining this status. The capital value of fishing rights for migratory salmonid fisheries is €165 million. Coarse fisheries contribute €1030 million to the economy. The central tenet to increasing participation in recreational salmonid fisheries is that an increase in stock size will result in more anglers accessing the fishery. This was examined for salmon on the rivers Usk and Lune where exploitation restrictions increased the number of salmon available to anglers. On the River Lune, the number of salmon available post‐intervention increased by 66%. There was no significant increase in catch while the number of anglers decreased by 16.3%. On the River Usk, the closure of the net fishery potentially resulted in an additional ～1200 salmon being available. Following closure, there was no significant change in rod catch or in the number of anglers. Increased participation is dependent less upon stock manipulation for coarse fisheries and more upon facilitating the activity. In recent years, urban fishery development programmes have provided improved access to local fishing opportunity. Also, new anglers have been targeted through campaigns such as Get Hooked on Fishing and the Scout Angler Badge.     

Rainbow trout effects on zooplankton in the reproductive area of the critically endangered hooded grebe

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Non‐indigenous fish in protected spaces: Trends in species distribution mediated by illegal stocking

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Post-stocking Movements and Recapture of Hatchery-reared Trout Released into Flowing Waters: Effect of Time and Method of Stocking

Hatchery-reared brown trout Salmo trutta L. (length 23–26 cm) were stocked in the Afon Taf, South Wales. The effects of ‘spot-’ and ‘scatter-planting’ and of stocking at 1 and 4 weeks prior to the start of the angling season were investigated. Data on the percentage recapture and post-stocking movements of the trout were obtained from tag returns. Higher percentage recaptures were recorded for ‘spot-plantings’ (65% and 31%) than for ‘scatter-planting’ (16%). Stockings made 1 week before the start of the angling season yielded better returns (17.1%) than those made 3 weeks earlier (2.2%). Neither ‘spot-’ nor ‘scatter-planting’ resulted in stocked fish contributing to the catch for an appreciably longer period of time. The majority of trout stocked were caught in the area of stocking irrespective of the method or time of planting.     

Combining fishery prohibition with stocking of landlocked salmon, Salmo salar L.: an effort to gain bigger yield and individual size

After stocking landlocked salmon, Salmo salar L., in Lake Änättijärvi, all fishing was prohibited for 18 months to provide time for the fish to establish and reach a larger size prior to capture. The potential benefit of the fishery prohibition was severely diminished by emigration of the stocked fish down the watercourse to other lakes. Only 19% of the recaptures of Carlin-tagged individuals came from Lake Änättijärvi. Also, the CPUE of test fishing in Lake Änättijärvi indicated a steep decline in the density of stocked fish during the fishery prohibition period. The mean weight of landlocked salmon in the combined recaptures from Lake Änättijärvi and other lakes downstream was 660 g. When fishing was not prohibited, the corresponding mean weight at recapture was 442 g. It is recommended that landlocked salmon stocking should be carried out in lakes with relatively low fishing pressure.     

Effects of stocked trout on native fish communities in boreal foothills lakes

Nasmith LE, Tonn WM, Paszkowski CA, Scrimgeour GJ. Effects of stocked trout on native fish communities in boreal foothills lakes.
Ecology of Freshwater Fish 2010: 19: 279–289. © 2010 John Wiley & Sons A/S Abstract – Ecological effects of stocking nonnative trout into lakes are receiving increased attention, especially in alpine environments. We assessed effects of stocked trout on native forage fishes in the boreal foothills of Alberta (Canada) by comparing fish density, population size structure and spatial and temporal activities in stocked and unstocked lakes over 3 years (2005–2007). The numerically dominant dace (primarily Phoxinus spp.) were larger in stocked lakes, consistent with size‐limited predation. Dace were also more crepuscular and concentrated on the lake‐bottom in stocked lakes, compared to more daytime activity in the water column in unstocked lakes. There were, however, no demonstrable effects of trout on the abundance of forage fish. The lack of major population‐level impacts of stocked trout suggests that current stocking practices, characteristics of boreal foothill lakes (e.g. thermal structure, abundant invertebrates, dense macrophytes) and/or behavioural adjustments of forage fish contribute to healthy native fish populations in our stocked lakes.     

Fish life history,angler behaviour and optimal management of recreational fisheries

To predict recreational‐fishing impacts on freshwater fish species, it is important to understand the interplay between fish populations, anglers and management actions. We use an integrated bioeconomic model to study the importance of fish life‐history type (LHT) for determining (i) vulnerability to over‐exploitation by diverse angler types (generic, consumptive and trophy anglers), who respond dynamically to fishing‐quality changes; (ii) regulations [i.e., minimum‐size limits (MSLs) and licence densities] that maximize the social welfare of angler populations; and (iii) biological and social conditions resulting under such socially optimal regulations. We examine five prototypical freshwater species: European perch (Perca fluviatilis), brown trout (Salmo trutta), pikeperch (Sander lucioperca), pike (Esox lucius) and bull trout (Salvelinus confluentus). We find that LHT is important for determining the vulnerability of fish populations to overfishing, with pike, pikeperch, and bull trout being more vulnerable than perch and brown trout. Angler type influences the magnitude of fishing impacts, because of differences in fishing practices and angler‐type‐specific effects of LHT on angling effort. Our results indicate that angler types are systematically attracted to particular LHTs. Socially optimal minimum‐size limits generally increase with LHT vulnerability, whereas optimal licence densities are similar across LHTs. Yet, both regulations vary among angler types. Despite this variation, we find that biological sustainability occurs under socially optimal regulations, with one exception. Our results highlight the importance of jointly considering fish diversity, angler diversity and regulations when predicting sustainable management strategies for recreational fisheries. Failure to do so could result in socially suboptimal management and/or fishery collapse.     

Yield to Anglers of Spring and Autumn Stocked, Hatchery Reared and Wild, Brown Trout (Salmo trutta L.)

Tagging experiments are described where hatchery over-yearlings and similar sized wild brown trout were spring-stocked in two small angling lakes. This was followed in the autumn with a stocking of hatchery fingerlings and wild fish. The spring-stocked hatchery fish gave the best return to anglers of 9.3% over the first two seasons, while the autumn-stocked hatchery fish apparently suffered heavy over-winter mortality — giving a return of only 1.3% over a comparable time period. Wild fish gave low return rates of 2.9 and 2.0% from spring and autumn stockings respectively, although netting exercises indicated that these survived longer in the lake than hatchery fish. Analysis of the methods of capture indicated that hatchery fish were more liable to be caught by bait fishing whereas fly fishing was the most successful for wild fish. Estimates were made of the relative cost effectiveness of the various types of fish in terms of returns to the angler.     

Towards an improved understanding of angler tourism in northern Australia

A human dimensions investigation into tourist anglers in a coastal recreational fishing hotspot in northern Australia is presented. Tourist anglers target one species, javelin grunter, Pomadasys kaakan (Cuvier), raising concerns about the sustainability of the fishery. Data from a survey of 427 tourist angling parties that fished in the coastal water off Karumba (Queensland) were analysed. Exploratory factor analysis was performed on angler target species and motivation for fishing to establish a typology of fishing intentions, with fishing for food found to be the principal factor. Anglers with high fishing for food factor scores were more consumptive, lower spending (per day) and more averse to any potential measures that might reduce legal possession (creel) limits or impose a cost of fishing. It was concluded that a combination of tourism and fisheries management interventions is required to safeguard Karumba's iconic javelin grunter fishery into the future. Diversification of tourist activity options can reduce the tourism industry's current reliance on high‐consumptive tourist anglers and increase the destination's appeal to non‐fishing tourists and low‐consumptive anglers. Modification of angler behaviour can be achieved through reduced possession limits for javelin grunter and possibly other target species, improved monitoring and law enforcement efforts, and targeted education and information.     

长江垂钓渔业调查研究

为了解长江干流各江段在长江十年禁渔的新形势下垂钓渔业状况，2017—2018年对长江干流872位垂钓者进行了走访调查。结果表明，长江干流垂钓者以中老年人为主，钓具类型主要为手竿和海竿，占钓具总量的80%以上。在长江上游及三峡库区，垂钓者渔具年投入50%以上样本在500元以下；在长江中下游50%以上样本在1 000元以上。长江上游、三峡库区、长江中游和长江下游的垂钓者人数分别估算为2 344、4 764、4 600和6 649位，对应江段年垂钓量分别估算为45.0、294.7、171.1和478.7 t，年垂钓量占对应江段鱼类资源现存量比例分别为8.6%、2.0%、1.8%和3.6%；垂钓对长江上游渔业资源影响相对较大，需要密切关注。为引导垂钓渔业的健康、可持续发展，建议划定禁钓区、禁钓期，建立天然水域钓具、钓法的白名单制度，建立科学的管理体制，深入挖掘传统渔业文化资源、树立垂钓渔业品牌。     

Factors influencing the yield of brown trout, Salmo trutta m. lacustris L., in northern Finnish lakes

Abstract Lake-to-lake variation in brown trout, Salmo trutta m. lacustris L., yield from stocking was examined in 34 lakes in northern Finland. The trout were mainly stocked as 2–3-year-old fish. Catch statistics were compiled with information on water quality, water level fluctuations, fishing effort and lake geomorphology. Absolute brown trout yields (kgha^-1) increased with increasing stocking rate, but there was an indication of non-linearity at higher stocking densities. Relative yields (kg per thousand trout released) were highest at low stocking rates. Stepwise multiple regression analysis was used to determine the best predictive model for lake-to-lake variability in brown trout yields. Seventeen measured regressands were used initially, and then replaced with scores obtained in a principal component analysis of highly correlated water quality variables and species-specific fish yields. Three major determinants of brown trout yields in these lakes were found in both analyses: fish community, stocking rate and fishing effort. Brown trout yields from stocking were higher in lakes with proportionally high yields of vendace or vendace and whitefish and proportionally low yields of pike.     

中东大西洋中部海域中上层鱼类资源结构与渔场分布

为了解中东大西洋中部海域中上层鱼类资源结构与渔场分布,对2007-2014年入渔FAO34渔区3.11和1.32小区(毛里塔尼亚专属经济区)从事中上层鱼类捕捞的7艘国内渔船的生产数据进行了分析。结果表明,我国入渔船只数量、入渔渔船总产量和作业渔船平均日产量均呈现先增加、后减少的趋势,且在2011年入渔渔船总产量和作业渔船平均日产量到达最大值,2012年入渔船只数量到达最大值。渔获种类主要包括沙丁鱼(Sardina pilchardus)、短体小沙丁鱼(Sardinella maderensis)、金色小沙丁鱼(Sardinella aurita)、日本鲭(Scomber japonicus)和竹筴鱼(Trachurus trachurus),各渔获种类的渔获量年际间波动较为明显。月均产量在17.2~23.6 t/haul,最高值和最低值分别出现在12月和8月;月均总产量在1 279.0~2 414.2 t,最高值和最低值分别出现在1月和8月,12月至次年3月为渔汛旺期。渔场季节变化现象明显,夏秋季向北移动,冬春季向南移动,20.0°~20.8°N、17.4°~18.0°W区域为高产量海域。该海域中上层鱼类洄游现象明显,这可能主要与该海域的不同洋流在不同月份的强弱变化有关,该海域整体渔业资源呈现一定衰退现象。建议渔船入渔该海域从事中上层鱼类捕捞持谨慎态度,加强该海域渔业资源的研究与保护。