Unaccounted mortality in northern Baltic Sea herring fishery—magnitude and effects on estimates of stock dynamics

Rahikainen, Mika; Peltonen, Heikki; Pönni, Jukka

doi:10.1016/j.fishres.2003.09.047

Cited by 17 publications

(12 citation statements)

References 14 publications

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“…However, the most of the herring that escape die shortly after. Furthermore, the results reported by Rahikainen et al [29] showed that the herring of the age group 0 and 1 are discarded underwater in larger numbers than landed while the actual fishing mortality at age 1 is estimated to be more than twice higher than its estimates based on the unadjusted data.…”

Section: Effect Of Fishingmentioning

confidence: 96%

Central Baltic Sea herring: effect of environmental trends and fishery management

Aps

Fetissov

Holmgren

et al. 2011

WIT Transactions on Ecology and the Environment

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Uncertainty is an endemic condition of the Baltic Sea herring (Clupea harengus membras, L) fishery management. It is a condition exacerbated by the fishing fleet overcapacity and consequent exploitation of the herring stock at a level believed to be unsustainable. Some sources of uncertainty are mainly related to biology and fishing technique: the unsolved problem of herring assessment and management units, the recruitment-environment relationship and the reduction in mean weights-at-age, uncertain ageing of fish, the problem of unaccounted fishing mortality caused by the fish selection through the trawl net. Fishing fleet overcapacity is believed to be behind of the regulatory overfishing when setting the Total Allowable Catches (TACs) higher than the scientific advice (decision overfishing) and tolerating the extensive underreporting of catches (implementation overfishing). Two scenarios for the Central Baltic Sea herring fishery management options are constructed and the Bayesian networks are used to represent and update uncertainties encountered in the process of the management related situation assessment. First scenario represents the current status of the fishery management resulting in fishing mortality (F) higher than F MSY -the fishing mortality that corresponds to the Maximum Sustainable Yield (MSY). The second scenario demonstrates the assumed potential impact of economic incentives (e.g. zoning, individual transferable quotas (ITQs), territorial use rights etc.) on the reduction of excessive fishing capacity and bringing actual fishing mortality closer to F MSY .

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Section: Effect Of Fishingmentioning

confidence: 96%

Central Baltic Sea herring: effect of environmental trends and fishery management

Aps

Fetissov

Holmgren

et al. 2011

WIT Transactions on Ecology and the Environment

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“…Herring and sprat were treated differently, as they are caught in pelagic fisheries regarded as fairly 'clean' with not much discards. Herring and sprat suffer from under-water discards (Rahikainen et al 2004), which is a type of discard not considered here 3 . Therefore, herring and sprat have a discard rate of zero.…”

Section: Discardsmentioning

confidence: 99%

Report of the 3rd working group meeting on optimization of fishing pressure in the Northeast Atlantic, Rhode Island March 2018

Sparholt

Hilborn

Horbowy

et al. 2019

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“…E093‐075‐A1 for details on the sigmoidal function S i ), including mortality both among fish trapped in and escaping from (i.e. underwater discarding) trawl gears, parameterized according to Rahikainen et al ().

…”

Section: Model Descriptionmentioning

confidence: 99%

Facilitation of fisheries by natural predators depends on life history of shared prey

Huss

Roos

Leeuwen

et al. 2014

Oikos

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Predators commonly share prey with human exploiters, intuitively suggesting that there is an inherent human-predator conflict through competition for prey. Here we studied the effects of fishing and predation mortality on biomass distributions and yields of shared prey using a size-structured model of competing populations, describing the life histories of Baltic Sea sprat and herring. Whereas both species responded in a similar fashion to increased fishing mortality, with decreasing juvenile and adult biomasses, we found that responses to predation mortality differed between species. Sprat only display weak compensatory responses with increasing predation mortality, while over a substantial range of mortalities there was a strong increase in adult (and total) herring biomass, i.e. overcompensation. The observed biomass overcompensation results from relaxed intraspecific competition as predation mortality increased, allowing for faster individual growth rates that in turn lead to a change in population composition (juvenile:adult biomass ratio). Our results suggest that the potential for biomass overcompensation is higher for species exhibiting substantial growth after maturation. Differences in size-selectivity of predators and fishing mortality resulted in a positive effect of predation mortality on fisheries yields, which can be explained by an overcompensatory response in adult herring biomass. Thus, somewhat counter intuitive, our results suggest that fishermen, depending on prey life history, may actually benefit from allowing for a higher abundance of predators, despite competing for shared prey.

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Unaccounted mortality in northern Baltic Sea herring fishery—magnitude and effects on estimates of stock dynamics

Cited by 17 publications

References 14 publications

Central Baltic Sea herring: effect of environmental trends and fishery management

Central Baltic Sea herring: effect of environmental trends and fishery management

Report of the 3rd working group meeting on optimization of fishing pressure in the Northeast Atlantic, Rhode Island March 2018

Facilitation of fisheries by natural predators depends on life history of shared prey

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