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  • 1
    Publication Date: 2016-07-13
    Description: Balanced harvesting (BH) has been proposed as an alternative to the paradigm of more selective fishing as practiced in most European and North American fisheries management. We examine options for the implementation of BH and evaluate the issues raised in such an implementation. Implementation is considered at the whole ecosystem level, in terms of the patterns of removal for all species, both commercial and bycatch. We suggest that a "laissez-faire" approach analogous to the African lakes where BH was first observed is inappropriate in managed developed world fisheries. We consider two further approaches: focusing on either the species caught or on the sizes of animal alone. We find that aiming to harvest all species with an exploitation rate appropriate to their productivity would require a degree of micro-management that is probably unachievable, with all captured species "choking" the fishery in sequence. The size-based approach works with an exploitation rate appropriate to the productivity at size, with no consideration of the species involved. This might superficially be easier to implement, as management would involve a limited number of size classes only. However, problems may arise due to the likely faster capture of the more easily catchable fish, and also likely targeting of the more valuable species within a size class. We identify a possible third option of "broad brush" métier-based management that may resolve some of these problems. Other issues include the management of protected, endangered, and threatened species (including mammals, reptiles, and birds), the management of already severely depleted stocks, and the capture of benthic invertebrates.
    Print ISSN: 1054-3139
    Electronic ISSN: 1095-9289
    Topics: Biology , Geosciences , Physics
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  • 2
    Publication Date: 2015-01-20
    Description: Demersal fisheries targeting a few high-value species often catch and discard other "non-target" species. It is difficult to quantify the impact of this incidental mortality when population biomass of a non-target species is unknown. We calculate biomass for 14 demersal fish species in ICES Area VIIg (Celtic Sea) by applying species- and length-based catchability corrections to catch records from the Irish Groundfish Survey (IGFS). We then combine these biomass estimates with records of commercial discards (and landings for marketable non-target species) to calculate annual harvesting rates ( HR ) for each study species. Uncertainty is incorporated into estimates of both biomass and HR . Our survey-based HR estimates for cod and whiting compared well with HR -converted fishing mortality ( F ) estimates from analytical assessments for these two stocks. Of the non-target species tested, red gurnard ( Chelidonichthys cuculus ) recorded some annual HR s greater than those for cod or whiting; challenging "Pope's postulate" that F on non-target stocks in an assemblage will not exceed that on target stocks. We relate HR for each species to two corresponding maximum sustainable yield (MSY) reference levels; six non-target species (including three ray species) show annual HR s ≥ HR MSY . This result suggests that it may not be possible to conserve vulnerable non-target species when F is coupled to that of target species. Based on biomass, HR , and HR MSY , we estimate "total allowable catch" for each non-target species.
    Print ISSN: 1054-3139
    Electronic ISSN: 1095-9289
    Topics: Biology , Geosciences , Physics
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  • 3
    Publication Date: 2015-07-15
    Description: The littorinid gastropod Littoraria flammea has been widely quoted as one of only three or four marine molluscs believed to have become extinct in historic times. It is easily recognized by its delicate, elongate, striped shell. We review the literature and available museum material to show that its only recorded locality was Shanghai and that it has not been collected since about 1855. We report the rediscovery of this species in salt marshes near Shanghai, where the habitat is under threat from invasive Spartina . For the first time we describe the penis, pallial oviduct and radula. These are the same as those of L. melanostoma , previously recorded only from Fujian province and southwards, where its shell is different from that of L. flammea . We now report a population of L. aff . melanostoma from between Fujian and Shanghai, with shells of intermediate form and colour. Analyses of sequences of COI, 12S and 28S genes do not support separation of these two Littoraria species, in terms of either reciprocal monophyly or genetic distance. Present evidence suggests that L. flammea could be only a distinctive morphological form or extreme of a cline, at the northern limit of the range of L. melanostoma .
    Print ISSN: 0260-1230
    Electronic ISSN: 1464-3766
    Topics: Biology
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  • 4
    Publication Date: 2013-01-17
    Description: The validity of the muricid subfamily Ergalataxinae has recently been confirmed with molecular data, but its composition and the relationships among its constituent genera remain unclear. In order to investigate this, we use four genes (28S rRNA, 12S rRNA, 16S rRNA and cytochrome c oxidase subunit I) to construct a Bayesian phylogeny of 52 ergalataxine species in 18 genera, representing c. 40% of the currently accepted species and 86% of the genera. This is the most complete phylogeny of this taxonomically confusing subfamily yet produced. Our results indicate the polyphyly of many traditional genera, including Morula , Pascula and Orania . In order to improve the correspondence between classification and phylogeny, we restrict the definition of Morula , resurrect Tenguella and elevate Oppomorus to full genus, but describe no new genera. Several species in this analysis could not be identified and may be new, but we do not describe them. Further molecular and morphological analyses, in the context of this framework, should help to resolve the remaining ambiguities in the classification of this subfamily. The oldest fossil member of the Ergalataxinae known to us is of Early Oligocene age.
    Print ISSN: 0260-1230
    Electronic ISSN: 1464-3766
    Topics: Biology
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  • 5
    Publication Date: 2012-04-10
    Description: Kraak, S. B. M., Reid, D. G., Gerritsen, H. D., Kelly, C. J., Fitzpatrick, M., Codling, E. A., and Rogan, E. 2012. 21st century fisheries management: a spatio-temporally explicit tariff-based approach combining multiple drivers and incentivising responsible fishing. – ICES Journal of Marine Science, 69: 590–601. Traditionally fisheries management has focused on biomass and mortality, expressed annually and across large management units. However, because fish abundance varies at much smaller spatio-temporal scales, fishing mortality can potentially be controlled more effectively if managed at finer scale. The ecosystem approach requires more indicators at finer scales as well. Incorporating ecosystem targets would need additional management tools with potentially conflicting results. We present a simple, integrated, management approach that provides incentives for "good behaviour". Fishers would be given a number of fishing-impact credits, called real-time incentives (RTIs), to spend according to spatio-temporally varying tariffs per fishing day. RTI quotas and tariffs could be based on commercial stocks and ecosystem targets. Fishers could choose how to spend their RTIs, e.g. by limited fishing in high-catch or sensitive areas or by fishing longer in lower-catch or less sensitive areas. The RTI system does not prescribe and forbid, but instead allows fishers to fish wherever and whenever they want; ecosystem costs are internalized and fishers have to take them into account in their business decisions. We envisage no need for traditional landings or catch quotas for the fleets while operating under the scheme. The approach could facilitate further devolution of responsibility to industry.
    Print ISSN: 1054-3139
    Electronic ISSN: 1095-9289
    Topics: Biology , Geosciences , Physics
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  • 6
    Publication Date: 2012-06-14
    Description: Saunders, R. A., O'Donnell, C., Korneliussen, R. J., Fässler, S. M. M., Clarke, M. W., Egan, A, and Reid, D. 2012. Utility of 18-kHz acoustic data for abundance estimation of Atlantic herring ( Clupea harengus ) – ICES Journal of Marine Science, 69: 1086–1098. Current acoustic survey protocols for Atlantic herring ( Clupea harengus ) abundance estimation are principally dependent upon 38-kHz backscatter data. This can constitute a substantial problem for robust stock assessment when 38-kHz data are compromised. Research vessels now typically collect multifrequency data during acoustic surveys, which could be used to remediate such situations. Here, we investigate the utility of using 18- and 120-kHz data for herring abundance estimation when the standard 38-kHz approach is not possible. Estimates of herring abundance/biomass in the Celtic Sea (2007–2010) were calculated at 18, 38, and 120 kHz using the standard 38-kHz target-strength (TS) model and geometrically equivalent TS models at 18 and 120 kHz. These estimates were compared to assess the level of coherence between the three frequencies, and 18-kHz-derived estimates were subsequently input into standard 38-kHz-based population models to evaluate the impact on the assessment. Results showed that estimates of herring abundance/biomass from 18 and 38 kHz acoustic integration varied by only 0.3–5.4%, and acoustically derived numbers-at-age estimates were not significantly ( p 〉 0.05) different from 1:1. Estimates at 120 kHz were also robust. Furthermore, 18-kHz-derived estimates did not significantly change the assessment model output, indicating that 18-kHz data can be used for herring stock assessment purposes.
    Print ISSN: 1054-3139
    Electronic ISSN: 1095-9289
    Topics: Biology , Geosciences , Physics
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  • 7
    Publication Date: 2011-11-24
    Description: Shephard, S., Gerritsen, H. D., Kaiser, M. J., Truszkowska, H. S., and Reid, D. G. 2011. Fishing and environment drive spatial heterogeneity in Celtic Sea fish community size structure. – ICES Journal of Marine Science, 68: 2106–2113. The Large Fish Indicator (LFI) is a univariate size-based indicator of fish community state that has been selected to support the OSPAR fish community Ecological Quality Objective (EcoQO). To operate this EcoQO, a survey-based LFI for each OSPAR region needs to be developed. However, fish communities in these regions are spatially heterogeneous, and there is evidence of within-region spatial variation in the LFI that could confound an overall indicator series. For Celtic Sea trawl-survey sites, spline correlograms indicate positive spatial autocorrelation at a similar range (~40 km) for the LFI and for fishing effort (h year –1 ) from vessel monitoring systems. Statistical models reveal a strong negative effect on annual LFI by site of fishing effort within a radius of 40 km. There was a weak effect of fishing within 20 km and no effect at 10 km. LFI also varied significantly with substratum and with local fish community composition identified by a resemblance matrix derived from the survey data. Finally, there was a weak effect of survey year on LFI. Spatial stratification of LFI calculations may be necessary when developing size-based indicators for OSPAR or Marine Strategy Framework Directive regions.
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    Electronic ISSN: 1095-9289
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  • 8
    Publication Date: 2011-11-24
    Description: Rihan, D., Graham, N., Reid, D. G., and Lordan, C. 2011. The provision of fishery information by ICES–WGFTFB to assessment working groups: use of information and lessons learned. – ICES Journal of Marine Science, 68: 1809–1814. ICES is now asked to provide advice that is more holistic in nature, including information on the influence and effects of human activities on the marine ecosystem. From a fishing-technology perspective, this includes information on how fishers respond and adapt to changes in regulatory frameworks, the impact of technology creep, ecosystem impacts, and changes in fleet dynamics. Recognizing the importance of this, in 2005, the ICES–Food and Agriculture Organization (FAO) Working Group on Fish Technology and Fish Behaviour (WGFTFB) began to collect data and information to support scientific advice on fisheries and ecosystem issues through a questionnaire circulated to its members. The information from the questionnaires was collated by the WGFTFB and submitted in the form of summary documents to various ICES assessment working groups. This paper describes the background to this initiative, the questionnaire structure, the type of information provided, and its utility.
    Print ISSN: 1054-3139
    Electronic ISSN: 1095-9289
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  • 9
    Publication Date: 2011-11-24
    Description: Shephard, S., Reid, D. G., and Greenstreet, S. P. R. 2011. Interpreting the large fish indicator for the Celtic Sea. – ICES Journal of Marine Science, 68: 1963–1972. The large fish indicator (LFI) was developed in the North Sea as a size-based indicator of fish community state. It is now established as OSPAR's fish community Ecological Quality Objective (EcoQO) metric and will be applied across all OSPAR regions. To produce a protocol for use when developing regional LFIs, the North Sea experience is interpreted using data from the Celtic Sea. Differences in fish community species composition and size distribution were reflected in a different species complex and large fish threshold (50 cm) for the Celtic Sea LFI. However, a lag of 12–14 years in the relationship between assemblage-averaged fishing mortality F com, y and the LFI suggested similar underlying ecological mechanisms to the North Sea. The indicator responded to changes in small fish biomass that follow fishing-induced changes in the level of predation by large demersal piscivores. The Celtic Sea LFI showed maximum observed values 〉0.40 before 1990, and 0.40 is here proposed as an EcoQO. Development of regional LFIs demands a flexible process rather than a strictly prescriptive protocol.
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    Electronic ISSN: 1095-9289
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  • 10
    Publication Date: 2011-11-24
    Description: Fitzpatrick, M., Graham, N., Rihan, D. J., and Reid, D. G. 2011. The burden of proof in co-management and results-based management: the elephant on the deck! – ICES Journal of Marine Science, 68: 1656–1662. Results-based management requires that outcomes can be demonstrated by industry and verified by managers on behalf of society. The core questions are: what outcomes, and how can they be proved? Existing fishery approaches to reversing the burden of proof are examined with focus on how proof is demonstrated. Outcomes can be measured in situ (on the vessel) or ex situ (at the stock or ecosystem level). In situ measures are preferable because they give direct measurements, although they can be invasive and costly. Ex situ results are only observable on scales that make it difficult to attribute them to specific management measures, or they may be influenced by external factors. Three main environmental impacts caused by fishing are assessed with respect to how industry can assume the burden of proof. The combined use of vessel-monitoring systems and benthic-impact models may offer a practical solution to the problem of managing fishery impacts on the benthos. Three Irish fisheries are assessed in terms of the feasibility of reversing the burden of proof. There are limits to the extent to which industry can assume the burden of proof, and the concept of sharing the burden of proof could be more realistic.
    Print ISSN: 1054-3139
    Electronic ISSN: 1095-9289
    Topics: Biology , Geosciences , Physics
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