Muskellunge Management: Fifty Years of Cooperation Among Anglers, Scientists, and Fisheries Biologists

2017 ◽  
Keyword(s):  
Open Water ◽  
Fishing Effort ◽  
High Rate ◽  
Yield Model ◽  
Size Classes ◽  
Catch And Release ◽  
Highly Sensitive ◽  
Equilibrium Yield ◽  
Age Structured ◽  
Catch Rates

<em>Abstract</em>.—The current Lake St. Clair Great Lakes Muskellunge <em>Esox masquinongy </em>fishery is entirely self-sustaining and dominated by a catch-and-release ethic. Catch rates of Lake St. Clair Muskellunge are among the highest documented for this species, and angler catches of trophy Muskellunge are considered relatively commonplace. The proximity of Lake St. Clair to many potential new Muskellunge anglers, interest among some anglers in restoring a long-prohibited winter spear fishery, and warming temperatures associated with climate change pose potential threats to the quality of this fishery. We developed an age-structured equilibrium yield model to project the likely effects of altered size and harvest limits, increased angling effort, establishment of a winter spearing season, or warming temperatures on open-water angling catch rates of three size-classes of Lake St. Clair Muskellunge (all fish ≥ age 1, legal-sized fish > 107 cm, and trophy-sized fish > 127 cm). Our modeling indicated that changes in regulations in the Lake St. Clair Muskellunge fishery were unlikely to result in substantial changes to catch rates of Muskellunge of any size-class. Similarly, the current high rate of voluntary release would largely buffer catch rates of all size-classes of Lake St. Clair Muskellunge from increases in fishing effort. Our simulation of a winter spearing fishery indicated that only high levels of spearing effort and harvest would reduce open-water catch rates to a degree that would likely be objectionable to anglers. In contrast, the predicted catch rates of legal-and trophy-sized fish were highly sensitive to modeled reductions in growth. As such, the major threat to this trophy Muskellunge fishery appears largely outside the traditional toolbox of fisheries managers, hastening the need for development of resilient management and monitoring plans for this valuable fishery.

Diet of the endangered spirlin (Alburnoides bipunctatus) at the centre of its distribution in Europe

2018 ◽  
Vol 69 (11) ◽  
pp. 1712
Author(s):  
L. Marszał ◽  
M. Grzybkowska ◽  
D. Błońska ◽  
J. Leszczyńska ◽  
M. Przybylski
Keyword(s):  
Resource Use ◽  
Diet Composition ◽  
Feeding Habits ◽  
Open Water ◽  
Size Class ◽  
Habitat Segregation ◽  
Chironomid Larvae ◽  
Size Classes ◽  
Taxonomic Groups ◽  
Distribution In Europe

The feeding habits of spirlin Alburnoides bipunctatus were investigated in a tributary of the River Vistula (Poland). To evaluate size-related patterns of resource use, fish were assigned to three size classes, defined according to size at first maturation: small (29–70-mm total length, TL), medium (71–90mm TL) and large (91–104mm TL). There was a significant ontogenetic shift in the feeding pattern among size classes, marked by differences in the proportion of the main taxonomic groups of prey consumed: small spirlin primarily consumed chironomid larvae, whereas medium and large spirlin showed a preference for Coleoptera, Ephemeroptera and imagines of unidentified insects. The proportion of prey taken from the water column was significantly lower for small- than medium- and large-sized spirlin. This difference was attributed to the benthic habits of small spirlin compared with medium and large spirlin. The shift to open water feeding in spirlin corresponded with sexual maturation, with habitat segregation between the smallest size class (comprising juveniles) and larger size classes (mature individuals). Size-specific changes in the diet composition of this species have not previously been documented.

Incidental capture of elasmobranchs in the bottom-set gill-net fishery off the south coast of Ireland

1994 ◽  
Vol 74 (4) ◽  
pp. 837-847 ◽  
Author(s):  
S.D. Berrow
Keyword(s):  
Fishing Effort ◽  
South Coast ◽  
Fishing Gear ◽  
The South ◽  
Blue Shark ◽  
Incidental Capture ◽  
Gill Net ◽  
Total Capture ◽  
Catch Rates ◽  
Basking Shark

The incidental capture of sharks in the bottom-set gill-net fishery off the south coast of Ireland was quantified by placing observers on commercial gill-netters for the duration of a fishing trip. Forty fishing trips were sampled resulting in 1,167 km and 19,760 km h of observed fishing effort. Sixty individual sharks of seven species were reported entangled in the fishing gear. Tope, porbeagle and six-gilled sharks were the most frequently caught species, with black-mouthed dogfish, blue shark, basking shark and starry smooth hound also recorded. Total fishing effort along the south coast was calculated and total capture extrapolated from observed catch rates. An estimated 6,000 sharks were caught in this fishery during the study period.

scholarly journals Characterization and Antibiogram of Escherichia coli Associated with Mortality in Broilers and Ducklings in Bangladesh

1970 ◽  
Vol 2 (1) ◽  
pp. 9-14 ◽  
Author(s):  
MT Islam ◽  
MA Islam ◽  
MA Samad ◽  
SML Kabir
Keyword(s):  
Escherichia Coli ◽  
Antibiotic Sensitivity ◽  
High Rate ◽  
E Coli ◽  
Sensitivity Pattern ◽  
Highly Sensitive ◽  
Biochemical Studies ◽  
Increasing Trend ◽  
Escherichia Coli Infection ◽  
Hemorrhagic Enteritis

Mortality in broilers (6.56%) and growing ducks (11.0%) caused by Escherichia coli was recorded in the experimental flocks study during the period from May to August 2003. E. coli organisms isolated from broiler birds affected with characteristic lesions of omphalitis and yolk sac infection, fibrinous pericarditis and peri-hepatitis , hemorrhagic enteritis, and accumulation of excessive pericardial and peritoneal fluid, whereas from ducks with lesions of hemorrhagic enteritis and extensive epicardial hemorrhages. Each of the 21 isolates collected from broilers and 11 isolates from ducks was characterized by cultural and biochemical studies, of which 8 isolates from broilers and 5 isolates from ducks were tested for antibiotic sensitivity with 9 different antibiotics. The antibiotic sensitivity pattern showed that the isolates were highly sensitive to ciprofloxacin but an increasing trend of resistance was recorded in broilers (7 / 9) than duck (4 / 9) isolates. It may be concluded from the results of this study that the high rate of E. coli infection in broilers and ducks along with the high resistance of isolates to antibiotics constitute a threat to the poultry industry in Bangladesh. Key words: Escherichia coli infection; mortality; broilers; ducks; characterization; antibiogram doi: 10.3329/bjvm.v2i1.1927 Bangl. J. Vet. Med. (2004). 2 (1) : 09-14

scholarly journals Recombination Can Cause Telomere Elongations as Well as Truncations Deep within Telomeres in Wild-Type Kluyveromyces lactis Cells

2010 ◽  
Vol 10 (2) ◽  
pp. 226-236 ◽  
Author(s):  
Laura H. Bechard ◽  
Nathan Jamieson ◽  
Michael J. McEachern
Keyword(s):  
Great Increase ◽  
Kluyveromyces Lactis ◽  
High Rate ◽  
Wild Type ◽  
Content Type ◽  
Normal Length ◽  
Highly Sensitive ◽  
Significant Process ◽  
Type Size

ABSTRACT In this study, we examined the role of recombination at the telomeres of the yeast Kluyveromyces lactis . We demonstrated that an abnormally long and mutationally tagged telomere was subject to high rates of telomere rapid deletion (TRD) that preferentially truncated the telomere to near-wild-type size. Unlike the case in Saccharomyces cerevisiae , however, there was not a great increase in TRD in meiosis. About half of mitotic TRD events were associated with deep turnover of telomeric repeats, suggesting that telomeres were often cleaved to well below normal length prior to being reextended by telomerase. Despite its high rate of TRD, the long telomere showed no increase in the rate of subtelomeric gene conversion, a highly sensitive test of telomere dysfunction. We also showed that the long telomere was subject to appreciable rates of becoming elongated substantially further through a recombinational mechanism that added additional tagged repeats. Finally, we showed that the deep turnover that occurs within normal-length telomeres was diminished in the absence of RAD52 . Taken together, our results suggest that homologous recombination is a significant process acting on both abnormally long and normally sized telomeres in K. lactis .

Historical dynamics of the demersal fish community in the East and South China Seas

2020 ◽  
Vol 71 (9) ◽  
pp. 1073 ◽  
Author(s):  
Jin Gao ◽  
James T. Thorson ◽  
Cody Szuwalski ◽  
Hui-Yu Wang
Keyword(s):  
South China ◽  
Collaborative Work ◽  
Habitat Preferences ◽  
Fishing Effort ◽  
Otter Trawl ◽  
Historical Records ◽  
China Seas ◽  
Important Species ◽  
Catch Rates ◽  
Abundance And Distribution

Taiwan has a long history of fishery operations and contributes significantly to the global fishery harvest. The East and South China seas are important fishing grounds for which publicly available data are very limited. More efforts are needed to digitise and analyse historical catch rate data to illuminate species and community changes in this region. In this study we digitised historical records of catch and effort from government fishery reports for nine commercial species caught by otter trawl, and reported quarterly from 1970 to 2001, from the East and South China seas. We analysed the four seasons and present abundance indices, distributions and among-species correlations for nine commercially important species from 1970 to 1988 (a period with high fishing effort) using a multispecies spatiotemporal model that estimates both covariation in multispecies catch rates, attributed to spatial habitat preferences and environmental responses, and indices representing trends in abundance and distribution. We found substantial spatial, temporal and spatiotemporal variation in the distribution of fishes and season-specific patterns. We recommend collaborative work from various adjacent countries to digitise historical records of fishing catch rates, because more records would potentially address scientific disagreements regarding trends in the abundance and distribution of commercial fishes in this region through comparative studies.

No fear of bankruptcy: the innate self-subsidizing forces in recreational fishing

2019 ◽  
Vol 77 (6) ◽  
pp. 2304-2307 ◽  
Author(s):  
Alf Ring Kleiven ◽  
Even Moland ◽  
U Rashid Sumaila
Keyword(s):  
Fishing Effort ◽  
The Self ◽  
High Rate ◽  
Recreational Fishing ◽  
Commercial Fishing ◽  
Fishing Industry ◽  
Fishing Sector ◽  
Local Residents

Abstract Recreational fishing, by both local residents and tourists, is a popular activity globally. The behaviour and motivation of recreational fishers is different from those of commercial fishers. Unlike the latter, the former are not dependent on making profits to continue fishing. Rather, the value of recreational fishing to those who engage in it is a combination of catches and experience values. The latter value implies that recreational fishers might continue fishing when they should not, analogous to the effect of subsidy in the commercial fishing sector. Hence, the term “self-subsidizing”: a fishery as one in which fishers subsidize themselves through an economic investment in gear and time from their non-fishery-based earnings. The consequence of which is that recreational fishers can continue fishing long after the commercial fishing industry has stopped fishing because their operations have become economically unviable. There is reason to argue that in many areas, recreational fishing effort, due to the self-subsidizing mechanism, is sustained at a high rate while stocks decrease. In this contribution, we describe the innate self-subsidizing forces in recreational fishing and discuss their implications.

scholarly journals Behavioural adjustment of fish to temporal variation in fishing pressure affects catchability: an experiment with angled trout

2020 ◽  
Vol 77 (1) ◽  
pp. 188-193 ◽  
Author(s):  
Barbara Koeck ◽  
Magnus Lovén Wallerius ◽  
Robert Arlinghaus ◽  
Jörgen I. Johnsson
Keyword(s):  
Temporal Variation ◽  
Internal State ◽  
Empirical Support ◽  
Population Level ◽  
Theoretical Models ◽  
Fishing Effort ◽  
Threat Perception ◽  
Fishing Pressure ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Catch Rates

In passive fisheries, such as angling, the fishing success depends on the ultimate decision of a fish to ingest the bait, based on an individual’s internal state, previous experience, and threat perception. Fish surviving capture by anglers are known to be less vulnerable, and catch rates usually quickly decline with increasing fishing effort. Previous theoretical models have thus suggested fishing closures as a means to recover responsiveness of fish to angling gear and maintain catch rates, yet empirical support remains limited. In a controlled replicated pond experiment, we evaluated the effects of temporal variation in fishing pressure on catch rates of rainbow trout (Oncorhynchus mykiss) by simulating short-term fishing closures. Fishing closures increased catch rates and population-level catchability by reducing threat perception at the population level and allowing released individuals to return to a vulnerable state. Our experimental results show that periodic fishing closures benefit catch rates but at the risk of aggravating the likelihood of overharvesting.

scholarly journals The economic cost of seabird bycatch in Argentinean longline fisheries

2011 ◽  
Vol 22 (1) ◽  
pp. 59-65 ◽  
Author(s):  
PATRICIA GANDINI ◽  
ESTEBAN FRERE
Keyword(s):  
Economic Cost ◽  
High Rate ◽  
Mitigation Measures ◽  
Economic Losses ◽  
Fishing Vessels ◽  
Order Of Magnitude ◽  
Patagonian Toothfish ◽  
Catch Rates ◽  
Longline Fisheries

SummarySeabird mortality in longline fisheries is believed to be an important cause of the reductions in many seabird populations worldwide, and results in reduced fishing efficiency and economic losses for fishing companies. We estimated the economic cost of not using seabird bycatch deterrents in Argentinean longline fisheries, with the intention of encouraging adoption of mitigation measures in those fisheries. We conducted the study in the Argentine ling Genypterus blacodes and Patagonian toothfish Dissostichus eleginoides fisheries from 2001 to 2006 on three fishing vessels. Data on the incidence of seabird bycatch were collected by seabird observers specially trained in seabird identification and data on the catch rates of target species, cost of bait and fish were provided by the fishing company, supervised by Federal Inspectors from the Provincial Fisheries Agency. To estimate the bait loss, we set lines both with and without the use of deterrents (streamer lines, night setting and strategic discharge of offal) in both fisheries. Seabird bycatch varies temporally and geographically, so to estimate economic losses using deterrents in each fishery, we used different bycatch rates/1000 hooks registered for different periods and fishing areas. Bycatch rates in the absence of deterrents were two birds/1000 hooks and 1.53 birds/1000 hooks for the Patagonian toothfish and ling fisheries, respectively. These rates equate to the loss of more than 1.5 and 2 million dollars over a 10 year period for each fishery. When estimations are made with lower mortality rates, economic losses declined abruptly and were in the order of hundreds of dollars/fishing trip, for the same period of time. Results show that using deterrents, long term profits for the fishing company increase at a considerably high rate (the decrease in monetary loss is an order of magnitude), and the mortality of seabirds decreases by the same proportion (CPUE of seabirds decreases from tens of thousands to a few hundred). In these fisheries, the use of mitigation measures that reduce bait loss and seabird mortality represents a win-win situation with benefits to conservation and fishing companies.

Use of Oceanographic Forecasts and Echosounders to Guide and Enhance an Inshore Gillnet Fishery for Atlantic Cod (Gadus morhua)

1993 ◽  
Vol 50 (10) ◽  
pp. 2129-2136 ◽  
Author(s):  
G. A. Rose ◽  
W.C. Leggett
Keyword(s):  
Gadus Morhua ◽  
Atlantic Cod ◽  
Fishing Effort ◽  
Shallow Waters ◽  
Gill Nets ◽  
Rule Of Thumb ◽  
Combined Use ◽  
Catch Rates ◽  
Depth Ranges ◽  
High Fish

Vessels fishing with gill nets for Atlantic cod (Gadus morhua) in the northern Gulf of St. Lawrence in 1985 and 1986 concentrated their fishing effort in shallow waters (<50 m) where cod densities were highest (to 0.5/m3). In both years, seasonal trends (June–August) in mean daily deployment depths of gill nets were positively correlated with mean depths at which cod were surveyed (1985, r = 0.71; 1986, r = 0.51, Ps < 0.05). Daily catch rate variability of individual vessels was accounted for by fish "flux" adjacent to nets (44%), vessel operator skill (19%), and "flux"–skill interaction (8%; total R2 = 0.71). A guided vessel directed to fish at sites predicted to have high fish flux (located down-current from high-density cod aggregations identified by echosounding within depth ranges forecast to be favorable to cod by "rule of thumb" wind-based oceanographic models) had higher catch rates (mean 1.3 t/d) than the fleet average and its own average fishing without guidance (means 0.4 t/d, P's < 0.05). Directed searches were of shorter duration (mean 0.5 h) than searches conducted at random (1.5 h). Combined use of echosounders and air–sea-based forecasts of cod distribution could help stabilize catch rates, especially at times of poor fish availability inshore.

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