Push net fishing seems to be responsible for injuries and post fishing mortality in glass eel in the Vilaine estuary (France) in 2007

Cikaso and Cimandiri estuaries are well known as the central area of glass eel fisheries in Sukabumi Regency. Local fishermen catch glass eels using two main fishing gears, namely traps and lift nets. Although both fishing gears' target operation is glass eels, many other fish species are also caught as bycatch. The present study aimed to identify glass eels and bycatch ichthyofauna in glass eel fisheries of the Cikaso and Cimandiri estuaries, Sukabumi. The research was carried out monthly from November 2020 to January 2021. Glass eels fishing gears collected a total of 21 fish species belonging to 15 families in both estuaries. According to the percentage ano-dorsal length measurement to total length (AD/TL), 3 species of glass eel were identified, i.e. Anguilla bicolor bicolor, A. nebulosa, and A. marmorata. These three species were the most abundant fish catches in both estuaries. More than 18 bycatch ichthyofauna were recorded and most of them are economically important fish, such as Ambassidae, Eleotridae, Engraulidae, Gobiidae, and Polinemidae. To sustain fishery management, the recording bycatch from glass eel fishery in the Cikaso and Cimandiri estuaries is necessary to be done regularly because they contribute to fishing mortality.

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Environmental influences on fish and shellfish production in the Northwest Atlantic

Environmental Reviews ◽

10.1139/a94-002 ◽

1994 ◽

Vol 2 (1) ◽

pp. 16-32 ◽

Cited By ~ 36

Author(s):

K.H. Mann ◽

K.F. Drinkwater

Keyword(s):

Environmental Factors ◽

Gadus Morhua ◽

Cold Water ◽

Climatic Factors ◽

Homarus Americanus ◽

Fishing Mortality ◽

Poor Growth ◽

Northwest Atlantic ◽

Grand Banks ◽

Fish And Shellfish

Evidence is reviewed, linking physical oceanographic processes in the marine environment to changes in fish and shellfish stocks in the Northwest Atlantic. A case history study of the cod (Gadus morhua) stock of the northern Grand Banks and Labrador Shelf indicates a long slow amelioration of the environment between about 1945 and 1965, followed by a deterioration in the period 1965–1992. The most important environmental factors for the cod stocks appear to have been salinity and temperature. The trends can be traced back to climatic factors involving the Icelandic Low and the Azores–Bermuda High. When the atmospheric pressure difference in winter tended to be high, there was a progressive increase in the area of sea ice off Labrador and in the volume of cold water at depth. These factors have been shown to affect temperature and salinity conditions on the Grand Banks in spring and summer and are associated with poor growth and recruitment in the cod stocks. A similar case study of lobster (Homarus americanus) stocks indicates that temperature and river discharge are important environmental correlates, but neither can be shown to fully account for the recent trends in the stocks. Evidence is reviewed to show that physical environmental processes also influence recruitment and distribution of stocks of haddock, capelin, and squid. Some of the problems with correlational analysis are also discussed. It is recognized that factors other than the environment are influencing the stocks. Fishing mortality (detailed consideration of which is not included in this review) has clearly been important. Interactions between environmental factors and fishing mortality are probably of major importance.Key words: ocean environment, fish production, recruitment, northern cod, American lobster.

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Among-stock comparisons for improving stock assessments of data-poor stocks: the “Robin Hood” approach

ICES Journal of Marine Science ◽

10.1093/icesjms/fsr039 ◽

2011 ◽

Vol 68 (5) ◽

pp. 972-981 ◽

Cited By ~ 72

Author(s):

André E. Punt ◽

David C. Smith ◽

Anthony D. M. Smith

Keyword(s):

Marine Science ◽

Fishing Mortality ◽

Robin Hood ◽

Estimated Parameters ◽

Stock Assessments ◽

Time Information

Abstract Punt, A. E., Smith, D. C., and Smith, A. D. M. 2011. Among-stock comparisons for improving stock assessments of data-poor stocks: the “Robin Hood” approach. – ICES Journal of Marine Science, 68: 972–981. An approach is outlined for conducting stock assessments in which parameters are estimated for multiple stocks at the same time. Information from data-rich stock assessments, e.g. trends in fishing mortality, and values for parameters of selectivity functions are provided to data-poor assessments in the form of penalties on the estimated parameters, which leads to stock assessments for the most data-poor stocks being informed by those for the most data-rich stocks. The method is applied for example purposes to data for nine stocks in Australia's southern and eastern scalefish and shark fishery. The results of the application confirm that results for data-rich stocks are little impacted by being assessed in conjunction with data-poor stocks and that the results for data-poor stocks can be qualitatively different when information for data-rich stocks is taken into account.

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Depleted marine fish stocks and ecosystem-based management: on the road to recovery, we need to be precautionary

ICES Journal of Marine Science ◽

10.1093/icesjms/fsq158 ◽

2010 ◽

Vol 68 (1) ◽

pp. 212-220 ◽

Cited By ~ 14

Author(s):

Anna Gårdmark ◽

Anders Nielsen ◽

Jens Floeter ◽

Christian Möllmann

Keyword(s):

Fisheries Management ◽

Marine Fish ◽

Assessment Model ◽

Fishing Mortality ◽

Fish Stocks ◽

The Road ◽

Stock Status ◽

Ecosystem Based Management ◽

Management Plans ◽

On The Road

Abstract Gårdmark, A., Nielsen, A., Floeter, J., and Möllmann, C. 2011. Depleted marine fish stocks and ecosystem-based management: on the road to recovery, we need to be precautionary. – ICES Journal of Marine Science, 68: 212–220. Precautionary management for fish stocks in need of recovery requires that likely stock increases can be distinguished from model artefacts and that the uncertainty of stock status can be handled. Yet, ICES stock assessments are predominantly deterministic and many EC management plans are designed for deterministic advice. Using the eastern Baltic cod (Gadus morhua) stock as an example, we show how deterministic scientific advice can lead to illusive certainty of a rapid stock recovery and management decisions taken in unawareness of large uncertainties in stock status. By (i) performing sensitivity analyses of key assessment model assumptions, (ii) quantifying the uncertainty of the estimates due to data uncertainty, and (iii) developing alternative stock and ecosystem indicators, we demonstrate that estimates of recent fishing mortality and recruitment of this stock were highly uncertain and show that these uncertainties are crucial when combined with management plans based on fixed reference points of fishing mortality. We therefore call for fisheries management that does not neglect uncertainty. To this end, we outline a four-step approach to handle uncertainty of stock status in advice and management. We argue that it is time to use these four steps towards an ecosystem-based approach to fisheries management.

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Challenges to quantifying glass eel abundance from large and dynamic estuaries

ICES Journal of Marine Science ◽

10.1093/icesjms/fsx182 ◽

2017 ◽

Vol 75 (2) ◽

pp. 727-737 ◽

Cited By ~ 1

Author(s):

Sarah Walmsley ◽

Julie Bremner ◽

Alan Walker ◽

Jon Barry ◽

David Maxwell

Keyword(s):

Large Scale ◽

Anguilla Anguilla ◽

Commercial Fishing ◽

European Eel ◽

Estuarine System ◽

Glass Eel ◽

The North ◽

Adequate Sampling ◽

South Shore ◽

Glass Eels

Abstract European eel Anguilla anguilla recruitment into the rivers of the northeastern Atlantic has declined substantially since the 1980s. Monitoring of recruiting juveniles, or glass eels, is usually undertaken in small estuaries and rivers. Sampling of large-scale estuaries is rare, due to the size of the sampling area and the resources needed to provide adequate sampling levels. Here we describe surveys for glass eels in the UK’s largest estuarine system, the Severn Estuary/Bristol Channel. We sampled across a 20 km-wide stretch of the estuary in 2012 and 2013, using a small-meshed net deployed from a commercial fishing trawler, and the surveys yielded over 2500 glass eels. Eels were more abundant in the surface layer (0–1.4 m depth) than at depth (down to 8.4 m depth), were more abundant close to the south shore than along the north shore or middle of the estuary, and were more abundant in lower salinity water. Numbers were higher in the second year than in the first and eels were more abundant in February than April. The difficulties and logistics of sampling in such a large estuary are discussed, along with the level of resources required to provide robust estimates of glass eel abundance.

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The influence of increased line-fishing mortality on the sex ratio and age of sex reversal of the venus tusk fish

Journal of Fish Biology ◽

10.1111/j.1095-8649.2002.tb00281.x ◽

2002 ◽

Vol 60 (2) ◽

pp. 301-318 ◽

Cited By ~ 27

Author(s):

J. R. Platten ◽

I. R. Tibbetts ◽

M. J. Sheaves

Keyword(s):

Sex Ratio ◽

Sex Reversal ◽

Fishing Mortality

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Stock assessment and projections incorporating discard estimates in some years: an application to the hake stock in ICES Divisions VIIIc and IXa

ICES Journal of Marine Science ◽

10.1093/icesjms/fsq029 ◽

2010 ◽

Vol 67 (6) ◽

pp. 1185-1197 ◽

Cited By ~ 16

Author(s):

C. Fernández ◽

S. Cerviño ◽

N. Pérez ◽

E. Jardim

Keyword(s):

Time Series ◽

Stock Assessment ◽

Reference Points ◽

Assessment Model ◽

Marine Science ◽

Fishing Mortality ◽

Change Over Time ◽

Age Structured ◽

Available Information ◽

Over Time

Abstract Fernández, C., Cerviño, S., Pérez, N., and Jardim, E. 2010. Stock assessment and projections incorporating discard estimates in some years: an application to the hake stock in ICES Divisions VIIIc and IXa. – ICES Journal of Marine Science, 67: 1185–1197. A Bayesian age-structured stock assessment model is developed to take into account available information on discards and to handle gaps in the time-series of discard estimates. The model incorporates mortality attributable to discarding, and appropriate assumptions about how this mortality may change over time are made. The result is a stock assessment that accounts for information on discards while, at the same time, producing a complete time-series of discard estimates. The method is applied to the hake stock in ICES Divisions VIIIc and IXa, for which the available data indicate that some 60% of the individuals caught are discarded. The stock is fished by Spain and Portugal, and for each country, there are discard estimates for recent years only. Moreover, the years for which Portuguese estimates are available are only a subset of those with Spanish estimates. Two runs of the model are performed; one assuming zero discards and another incorporating discards. When discards are incorporated, estimated recruitment and fishing mortality for young (discarded) ages increase, resulting in lower values of the biological reference points Fmax and F0.1 and, generally, more optimistic future stock trajectories under F-reduction scenarios.

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What are the best upland river characteristics for glass eel restocking practice?

The Science of The Total Environment ◽

10.1016/j.scitotenv.2021.147042 ◽

2021 ◽

pp. 147042

Author(s):

Billy Nzau Matondo ◽

Jean-Philippe Benitez ◽

Arnaud Dierckx ◽

Séverine Renardy ◽

Xavier Rollin ◽

...

Keyword(s):

Glass Eel

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Partial fishing mortality per fishing trip: a useful indicator of effective fishing effort in mixed demersal fisheries

ICES Journal of Marine Science ◽

10.1016/j.icesjms.2005.10.003 ◽

2006 ◽

Vol 63 (3) ◽

pp. 556-566 ◽

Cited By ~ 65

Author(s):

Adriaan D. Rijnsdorp ◽

Niels Daan ◽

Willem Dekker

Keyword(s):

Fishing Effort ◽

Fine Tuning ◽

Positive Trend ◽

Fishing Mortality ◽

Auxiliary Equipment ◽

Solea Solea ◽

Seasonal And Spatial Variations ◽

Sea Beam ◽

Quota Management ◽

Engine Power

Abstract Effort management has been proposed as an alternative for quota management in mixed demersal fisheries. It requires a metric to estimate the fishing mortality imposed by a given quantity of nominal fishing effort. Here, we estimate the partial fishing mortality rate imposed by one unit of fishing effort (Fpue) during individual fishing trips and explore the usefulness of this indicator for managing North Sea beam trawlers >300 hp targeting sole (Solea solea) and plaice (Pleuronectes platessa). Fpue is positively related to vessel engine power, and increased annually by 2.8% (sole) and 1.6% (plaice). The positive trend was due to an increase in skipper skills and investment in auxiliary equipment, the replacement of old vessels by new ones and, to a lesser extent, to upgrade engines. The average Fpue imposed per day at sea by a 2000 hp beam trawler was estimated to be 1.0 × 10−5 (sole) and 0.6 × 10−5 (plaice), and it showed substantial seasonal and spatial variations. The Fpue of sole and plaice were negatively related in summer and showed no relationship in winter. The existence of predictive seasonal and spatial patterns in Fpue opens up the possibility of fine-tuning management by directed effort restrictions and uncoupling management of plaice and sole.

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Can stock–recruitment points determine which spawning potential ratio is the best proxy for maximum sustainable yield reference points?

ICES Journal of Marine Science ◽

10.1093/icesjms/fst105 ◽

2013 ◽

Vol 70 (6) ◽

pp. 1075-1080 ◽

Cited By ~ 6

Author(s):

Christopher M. Legault ◽

Elizabeth N. Brooks

Keyword(s):

Life History ◽

Mortality Rate ◽

Maximum Sustainable Yield ◽

Reference Points ◽

Sustainable Yield ◽

Marine Science ◽

Fishing Mortality ◽

Scatter Plots ◽

Stock Recruitment ◽

Spawning Potential Ratio

Abstract Legault, C. M., and Brooks, E. N. 2013. Can stock–recruitment points determine which spawning potential ratio is the best proxy for maximum sustainable yield reference points? – ICES Journal of Marine Science, 70: 1075–1080. The approach of examining scatter plots of stock–recruitment (S–R) estimates to determine appropriate spawning potential ratio (SPR)-based proxies for FMSY was investigated through simulation. As originally proposed, the approach assumed that points above a replacement line indicate year classes that produced a surplus of spawners, while points below that line failed to achieve replacement. In practice, this has been implemented by determining Fmed, the fishing mortality rate that produces a replacement line with 50% of the points above and 50% below the line. A new variation on this approach suggests FMSY proxies can be determined by examining the distribution of S–R points that are above or below replacement lines associated with specific SPRs. Through both analytical calculations and stochastic results, we demonstrate that this approach is fundamentally flawed and that in some cases the inference is diametrically opposed to the method's intended purpose. We reject this approach as a tool for determining FMSY proxies. We recommend that the current proxy of F40% be maintained as appropriate for a typical groundfish life history.

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