摘要:

From an ecological perspective, predation, competition or resource partitioning, and abiotic factors interact to affect species distribution and abundance. To make management recommendations, I review research dealing with the relative influence of these factors in determining stocking success of muskellunge Esox masquinongy. Survival of stocked muskellunge is affected by losses to resident predators. Prey preference and composition are also important, and better muskellunge survival and growth occurs in systems with soft-rayed or fusiform prey rather than in centrarchid-dominated systems. However, potential for competition with resident fishes has not been carefully considered. Abiotic factors, particularly temperature, can influence stocking mortality and subsequent growth. Survival increases with size and is maximized with large muskellunge fingerlings (>240 mm), but cost-effectiveness can vary substantially with predator and prey populations. Hatchery rearing techniques can also affect muskellunge stocking success. Pellet-reared fish have lower survival than minnow-reared fish because predation mortality is higher, but both groups exhibit similar food consumption and growth. The parental population can affect survival and growth because temperature-related differences in bioenergetic variables occur among muskellunge populations. In addition to compromising genetic integrity, the mixing of populations with different physiological characteristics may have negative consequences for native populations. Thermal regimes of recipient waters should be considered in choosing the most appropriate population for stocking outside the native range. Muskellunge stocking should be pursued within an ecological context that integrates the relative importance of predation, competition, and abiotic factors. This framework provides a guide for making management decisions concerning populations, hatchery rearing techniques, sizes, and timing of muskellunge introductions into systems with specific characteristics.

ISSN:0275-5947    

DOI:10.1577/1548-8675(1999)019<0238:AECFET>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

We examined the effects of rearing method and size at stocking on the survival of muskellunge Esox masquinongy in Chautauqua Lake, New York. Since 1961, changes in rearing methods have coincided with declining abundance of adult muskellunge. In particular, a change from pond rearing to trough rearing coincided with declining catches of adult muskellunge in pound nets. The decline was only partly reversed by changes from trough rearing to pond finishing of fingerlings. Changes in survival to age 5 from 1961 to 1996 indicated that both rearing method and stocking length significantly affected survival. Greater length at stocking resulted in higher survival rates. After accounting for length at stocking, survival was highest for pond-reared fingerlings, intermediate for pond-finished fingerlings, and lowest for trough-reared fingerlings. A modified Ricker stock–recruitment model indicated that survival of fingerlings declined over time. Increases in the adult stock of walleye Stizostedion vitrium since the 1960s may have increased predatory pressure on fingerlings and increased the importance of greater length at stocking.

ISSN:0275-5947    

DOI:10.1577/1548-8675(1999)019<0249:EOSSAR>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

The muskellunge Esox masquinongy is an important sport fish in Wisconsin and elsewhere, but more information about its diet is needed to better understand its role in aquatic systems and its effects on other fish. Stomach contents were examined for 1,092 muskellunge (226–1,180 mm total length, TL) captured in the littoral zone from 34 Wisconsin water bodies from Jul 1991 to Oct 1994. Food occurred in 34.3% (N = 375) of the stomachs, with most (74%) containing a single item. Overall, the proportion of muskellunge with food differed significantly among seasons, with the greatest proportion occurring in fall (69.0%), followed by summer (53.5%) and then spring (25.4%). Prey items consisted of 547 fish, representing 12 families and 31 species, along with 35 nonfish items; fish composed 98% of the diet. Relative importance values of diet items varied by taxa, season, and water body, but the main food items eaten by muskellunge in each season were yellow perch Perca flavescens and white sucker Catostomous commersoni. Black basses Micropterus spp., northern pike Esox lucius, walleye Stizostedion vitreum, cyprinids, and other taxa were less common in the diet. Prey fish ranged in size from 6% to 47% of muskellunge total length and prey length increased significantly as muskellunge size increased. Yet the size of prey in proportion to muskellunge size remained the same for all sizes of muskellunge. The results of this study indicate that, if readily available, yellow perch and catostomids will compose a large proportion of the muskellunge diet. Additional studies assessing muskellunge diet among lakes having different prey community types and assessing diet in deeper offshore areas of lakes are needed to better understand the role that muskellunge play in aquatic communities.

ISSN:0275-5947    

DOI:10.1577/1548-8675(1999)019<0258:DOMINW>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Growth of muskellunge Esox masquinongy from 12 Ontario sources was investigated by examining 582 samples from the Cleithrum Project archive and other specific studies; 88% of the samples were from angler-caught “trophy” fish. We detail sampling problems and develop methods for resolving them. Muskellunge from some sources were unsexed; sex was discriminated (probability of correct classification, 98.3%) from the von Bertalanffy growth parameters ultimate length (L∞) and growth coefficient, K. When one sex was inadequately sampled, the von Bertalanffy growth parameters of one sex were used to estimate those of the other. When samples were small and inadequate (<11), we used concordance sum of squares to match growth and give an interim estimate from the adequately sampled source with the best growth match. In Ontario populations, mean ultimate total lengths range widely: from 81.4 to 140.0 cm for females and from 70.7 to 115.9 cm for males. Females can be grouped into three types of growth, producing either large-, medium-, or small-bodied fish (ranging from 140 to 127 cm, 126 to 114 cm, and 113 to 102 cm and smaller, respectively). We describe and categorize growth and growth potential to establish standards for detecting change in exploitation and for reviewing minimum size limits (currently underway) based on growth biology to help sustain and even increase the size of muskellunge populations while producing high-quality trophy fisheries.

ISSN:0275-5947    

DOI:10.1577/1548-8675(1999)019<0271:GAULOM>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Wisconsin's populations of muskellunge Esox masquinongy provide an important recreational fishery. Our objectives were to (1) evaluate progress of the Wisconsin Department of Natural Resources muskellunge management plan, (2) examine subsequent changes in the fishery, and (3) evaluate Wisconsin's muskellunge waters classification system. With the goal of maintaining viable populations and a trophy fishery, the 1979 plan endorsed more restrictive harvest regulations, an increased supply of muskellunge fishing opportunities, and increased data collection. Since the 1980s, muskellunge fishing opportunities have increased 75% in terms of lake acres and 51% in terms of stream miles. Hatchery production and stocking efficacy have improved to the point where the department needs to reevaluate current stocking practices. With the establishment of a shorter season, a higher statewide minimum length limit, and an increased use of special regulations, harvest regulations have become progressively more restrictive. Concurrently, muskellunge-specific fishing effort increased from the 1980s to the 1990s. Harvest of muskellunge declined even though catch remained unchanged. Reducing the season length and increasing the overall availability of muskellunge angling opportunities did not reduce fishing effort on premier muskellunge lakes, but rather compressed effort into a shorter time period on increasingly popular waters. The reduction in harvest was associated with more restrictive regulations and voluntary changes in angler behavior (i.e., increased release of legal-sized muskellunge). Without voluntary release, it is likely that angler harvest would have exceeded levels needed to sustain the fishery. The muskellunge waters classification system, based originally on professional judgment, proved useful in distinguishing the fishery potential of lakes. Preliminary evidence suggests that voluntary constraints on harvest have not improved the size-structure of Wisconsin muskellunge populations because of continued harvest of nontrophy-sized fish. If our goal remains to provide a trophy fishery, more restrictive size-specific restrictions on harvest may be needed.

ISSN:0275-5947    

DOI:10.1577/1548-8675(1999)019<0291:TIWSMF>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Minimum length limits are a commonly used management tool for protecting fisheries from exploitation and for improving population size structure. However, little is known about the effects of minimum length limits on populations of muskellunge Esox masquinongy. We monitored changes in the muskellunge population in Bone Lake, a 1,781-acre lake in northwest Wisconsin over a 31-year period (1964–1995) during which time length limits were changed from 30 in to 34 in and from 34 in to 40 in. These changes were compared with population changes in nearby Deer Lake (807 acres), where the length limit remained at the statewide minimum of 32 in. Mean length of adult muskellunge in Bone Lake increased from 31.3 in in 1964 to 36.0 in in 1995. Adult (≥30-in) muskellunge abundance in Bone Lake increased more than five-fold during the study and reached a density of 0.99 fish/acre. Abundance of larger (≥38-in) muskellunge increased 269% following minimum length limit increases between 1982 and 1995. Relative weight (Wr) of Bone Lake muskellunge decreased during the study, suggesting intraspecific competition for food resources. The muskellunge population in Deer Lake also had positive increases in size structure, but the increases were not as great as those in Bone Lake, and population abundance did not change. Results from this study suggest that high minimum length limits can increase abundance and mean length of a muskellunge population, but biologists need to consider long-term effects on the fish community if high densities are achieved.

ISSN:0275-5947    

DOI:10.1577/1548-8675(1999)019<0300:EOLLOM>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Distribution, abundance, and survival of age-0 muskellunge Esox masquinongy were evaluated at 10 bays in the Thousand Islands section of the St. Lawrence River over a 7-year period, 1990–1996. Muskellunge fry (24 mm) identified with thermal or oxytetracycline otolith markers were stocked in 1990–1992, 1994, and 1996, and fin-clipped fingerlings (76 mm) were stocked in the bays in 1994 and 1996. Success of the stockings was evaluated to examine the feasibility of enhancing bays that have natural reproduction (natural) and establishing populations in unused bays (restoration). Most age-0 muskellunge were found in shallow habitats (<1.5 m), and success of capture by seining decreased with increasing water depth. Estimates of age-0 abundance by mark–recapture and catch–area were not significantly different. Population density ranged from 0 to 42 muskellunge/ha of nursery habitat, and no significant differences were observed between natural (18.8 fish/ha) and restoration bays (20.5 fish/ha). For all years combined, 67% of fish in natural bays originated from fry stocking, compared with 74% in restoration bays. No significant difference in contribution to age-0 abundance by origin (fry, fingerling, wild) was observed between natural and restoration bays. No stocking occurred in 1993 and 1995, but wild age-0 muskellunge were captured in 9 of 10 bays. The presence of wild muskellunge in 4 of 5 restoration bays indicated that these bays were incorrectly characterized as lacking natural reproduction. Survival of stocked fry was relatively low (0–3%), compared with survival of fingerlings (0–35%), but stocked fry contributed more to abundance (over 50%) than wild or fingerling sources. Due to its success, fry stocking should be reconsidered as a useful management tool for enhancing and restoring muskellunge populations.

ISSN:0275-5947    

DOI:10.1577/1548-8675(1999)019<0309:DAASOA>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor