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  • 1
    Publication Date: 2018-11-20
    Description: Atlantic cod (Gadus morhua) is an important recreational and commercial fisheries target species in the Northern hemisphere. Release rates are high in the recreational fishery due to regulatory and voluntary catch-and-release practice. Although post-release mortality of cod is relatively low, there is potential for further reductions. The most effective way to reduce post-release mortality is to minimize the catch of sublegal fish or non-target species and to reduce hooking injuries by using more selective fishing methods. This study investigated the influence of the lure/bait type on: (1) size of fish, (2) catch and harvest, (3) proportion of bycatch, (4) hooking location, and (5) injury (bleeding) in the western Baltic Sea recreational cod fishery. Data were collected via random onboard sampling of 35 charter vessel angling trips (778 anglers) and during two supplementary studies in the western Baltic Sea. Overall, the median total length was significantly higher for cod caught on artificial lures (39 cm) than for cod caught on natural bait (28 cm), leading to a 43% higher proportion of sublegal (〈38 cm) cod for bait than for lure. Median catch-per-unit-efforts (number of captured cod per angling hour) did not differ significantly between lure and bait angling (both: 0.49 cod per hour), whereas the median harvest-per-unit-effort (number of captured cod ≥ minimum landing size (38 cm) per angling hour) was significantly higher for lure (0.24 cod ≥38 cm per hour) than for bait angling (0.06 cod ≥38 cm per hour). The incidence of deep hooking and severe bleeding was significantly higher for bait angling. Furthermore, bait angling significantly increased bycatch of other species dominated by whiting (Merlangius merlangus) and European flounder (Platichthys flesus). Cod anglers can reduce the catch of sublegal cod and non-target species and minimize hooking injuries of released fish by using lures instead of bait in the western Baltic Sea. Thus, voluntary terminal gear recommendations may be an effective tool for anglers and managers to increase selectivity in recreational cod fisheries.
    Type: Article , PeerReviewed
    Format: text
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  • 2
    ISSN: 1365-2427
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: 1. Research has often focused on the pelagic areas of lakes; the littoral zone has received less attention. The few studies concerning fish distribution in littoral habitats have concentrated on stands of submersed macrophytes, whereas other littoral habitat types have seldom been investigated.2. This study aimed to predict the occurrence of juvenile fish in several littoral habitats of a shallow lake as a function of food availability, complexity of habitat structure, water depth and substrate. Habitats comprising reed, woody structures, and two open water areas differing in depth were sampled for fish and invertebrate biomasses on two shores, over 6 months and during both daylight and at night.3. The juvenile fish community consisted almost exclusively of 0+ and 1+ roach and perch. There was a strong diel component in habitat use, with a predominant occurrence of fish in complex habitats (mainly woody structures) during the day, and a partial migration towards the open habitats at night, more strongly expressed in roach than in perch.4. The diet of all fish groups was relatively constant over the seasonal cycle, and was independent of habitat. There was a higher degree of planktivory in roach than in perch, but both species fed on benthic macroinvertebrates to a substantial extent.5. According to a logistic regression model, the biomass of potential food organisms in the different habitats had little predictive effect on the spatial distribution of the fish, whereas the structural complexity of the habitats combined with the diel cycle explained about 28% of the occurrence patterns in 0+ and 1+ perch and 1+ roach.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Freshwater biology 50 (2005), S. 0 
    ISSN: 1365-2427
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: 1. Research has often focused on pelagic food chains and processes of lakes; less is known about the contribution of benthic energy flows to whole-lake ecosystem energetics. This stems from the fact that the shoreline and littoral habitats, which provide a key linkage between sediment and water column, have only recently become a significant focus for study.2. This study aimed to quantify the feeding and phosphorus allocation of a juvenile fish community in a littoral zone of a shallow lake in response to the biomass succession of the invertebrate prey community. Habitats comprising reed and adjacent open water were sampled over two consecutive years during day and night.3. Although there were substantial year-to-year differences in the biomass of invertebrates, the fish community composition, diet consumption rates and phosphorus allocations were very similar in both study years. Biomasses and predation impacts by juvenile fish on prey groups were substantially higher within the reeds than in the adjacent open water habitat. This may be explained by the refuge-seeking behaviour of the fish.4. In general, invertebrates were negligibly influenced by fish feeding, with the exception for a strong top-down control of large cladocerans. In response to the resulting low Daphnia biomass, fish were forced to switch to a higher degree of benthivory. Consequently, juvenile fish in littoral reed stands may shift benthic-derived energy and phosphorus via the excretion of soluble reactive phosphorus into the open water.
    Type of Medium: Electronic Resource
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