Assessing fishery and ecological consequences of alternate management options for multispecies fisheries

Demands for management advice on mixed and multispecies fisheries pose many challenges, further complicated by corresponding requests for advice on the environmental impacts of alternate management options. Here, we develop, and apply to North Sea fisheries, a method for collectively assessing the effects of, and interplay between, technical interactions, multispecies interactions, and the environmental effects of fishing. Ecological interactions involving 21 species are characterized with an ensemble of 188 plausible parameterizations of size-based multispecies models, and four fleets (beam trawl, otter trawl, industrial, and pelagic) characterized with catch composition data. We use the method to evaluate biomass and economic yields, alongside the risk of stock depletion and changes in the value of community indicators, for 10 000 alternate fishing scenarios (combinations of rates of fishing mortality F and fleet configuration) and present the risk vs. reward trade-offs. Technical and multispecies interactions linked to the beam and otter trawl fleets were predicted to have the strongest effects on fisheries yield and value, risk of stock collapse and fish community indicators. Increasing beam trawl effort led to greater increases in beam trawl yield when otter trawl effort was low. If otter trawl effort was high, increases in beam trawl effort led to reduced overall yield. Given the high value of demersal species, permutations of fleet effort leading to high total yield (generated primarily by pelagic species) were not the same as permutations leading to high catch values. A transition from F for 1990 to 2010 to FMSY, but without changes in fleet configuration, reduced risk of stock collapse without affecting long-term weight or value of yield. Our approach directly addresses the need for assessment methods that treat mixed and multispecies issues collectively, address uncertainty, and take account of trade-offs between weight and value of yield, state of stocks and state of the environment

Report of the working group on fisheries acoustics science and technology (WGFAST)

The Working Group on Fisheries Acoustics Science and Technology (WGFAST) met at the Food and Agricultural Organisation of the United Nations in Rome, Italy, from 19–22 April 2005. David A. Demer, USA, was Chair, Alex De Robertis, USA, was Rapporteur and Jessica D. Lipsky, USA, was the Recorder. There were 83 participants from 16 countries. a ) The first topic was “Measuring underwater radiated noise from survey vessels and its effects on fish”. Quiet vessels have distinct advantages over conventional vessels. It has been shown that herring did not respond to a vessel which com-plies with the ICES Cooperative Research Report No. 209 specification for radi-ated noise. Reductions in high frequency vessel noise have also increased acous-tic detection ranges for fish and zooplankton. However, it is clear that some spe-cies, under some circumstances, avoid even quiet survey vessels. Thus, a variety of stimuli produced by vessels such as light and particle motion, as well as radi-ated noise, may cause fish to react to a survey vessel. Noise reduced vessels pro-vide new opportunities to investigate these stimuli. WGFAST recommends that research in this area should proceed swiftly and focus on: i) determining which species of fish react to conventional and quiet survey vessels and under what cir-cumstances; ii) the stimuli for their behaviours; and iii) the design requirements for vessels surveying these species in sensitive situations. Additionally, for cases in which fish avoidance is inescapable, survey biases should be estimated. Devel-opment of economical and portable noise measurement systems is also encour-aged. b ) The second topic was “Technologies for remote species identification (low-frequency, Doppler, multi-frequency, broad bandwidth, data integration, optical sensors)”. Species identification can be one of the major sources of uncertainty in acoustic surveys of fish and zooplankton abundance, and it is vital to multi-species and ecosystem studies. Substantial progress was reported on a variety of methods for remote species identification. Such methods enable more automated and objective data processing, reduced uncertainty in acoustic estimates of fish biomass, economical ecosystem investigations and studies of predator-prey inter-actions, and may also facilitate a reduction of by-catch during commercial fishing operations. It was noted that further progress towards species identification will likely require a combination of acoustic and other measurements. Because net sampling is typically used to identify acoustic scatterers, gear selectivity can add substantial uncertainty to acoustic surveys. Thus, the WGFAST encourages re-search on random and systematic error in net sampling, and development of new methods for verifying acoustic scatterers. Particularly promising are underwater stereo video instrumentation and analysis methods. c ) The third topic was “Alternative technologies (small-craft, buoys, ROV, AUV, gliders, fishing vessels, multi-beam sonar, acoustic cameras), with special atten-tion to shallow water and near boundary assessments (coastal, riverine, demersal and epipelagic species, and bottom typing)”. Measurement platforms other than research vessels are being used to economically make measurements on ecologi-cally important temporal and spatial scales. For example, acoustic instruments are being deployed on buoys, landers, autonomous underwater vehicles, remotely op-erated vehicles, and fishing vessels. Expanded use of these platforms is impera-tive for successful ecosystem-based fisheries management. Progress was also re-ported on development of multi-beam sonars, and analyses of their data for bio-mass estimation. Finally, productive collaborations between commercial manu-facturers and the scientific community were reported and encouraged. d ) The fourth topic was “Target strength (modelling and measurements)”. There is a growing body of evidence indicating that a first-order approximation of TS ver-sus log-length is generally insufficient to accurately and precisely estimate fish TS. It was shown that factors such as fish orientation (tilt, roll, and yaw), age-dependent changes in morphology, and region-dependent relations between fish mass, length, and swimbladder volumes can eclipse the effect of fish length on their TS. Exemplifying this point was another study showing a bimodal TS distri-bution from herring characterized with a unimodal length distribution. e ) WGFAST recommends that it next meets at CSIRO in Hobart, Tasmania, on 27, 28, 29, and 30 March, 2006 to examine works in the following research areas: i) Fish behaviour in response to noise and other vessel related stimuli; ii) Survey techniques for epi-benthic, epi-pelagic and shallow water species; iii) Acoustical species ID techniques for multi-species assessments, ecosystem studies, by-catch reduction, and objective and automated data processing; iv) Instrumentation, survey design, and data analysis techniques for studying aquatic ecosystems, with special attention to the estimation and use of meas-urement uncertainty in statistical analyses of multi-variate time series, and techniques for integrating multi-disciplinary data to elucidate functional rela-tionships; and v) Target strength (modelling and measurements). f ) WGFAST recommends that SGASC and SGTSEB both be extended for another year, retaining their current Chairs, to complete their respective CRRs; and SGAFV and SGASC also meet in Hobart on 25–26 March, and 31 March-2 April, respectively. g ) WGFAST recommends research on: 1) noise and other vessel related stimuli for fish behaviour; 2) video and still camera instrumentation and data processing; and 3) instrumentation and methods for remote species identification. These topics should be considered for one or more new Study Group at the 2006 meeting. h ) WGFAST and WGFTFB jointly recommend that a Task Force be formed, lead by David Somerton, USA, to: evaluate the state-of-the-art in optical imaging and analysis technologies and define the ICES community’s requirements for addi-tional optical technology. i ) WGFAST recommends a review of the ecosystem-based fisheries management strategies developed and employed over the past two decades by international communities such as CCAMLR. Accordingly, one or more keynote speakers from CCAMLR and or CSIRO will be invited to the 2006 WGFAST meeting. j ) WGFAST recommends that the ICES sponsored “2008 Symposium on Fisheries Acoustics and Technology for Aquatic Ecosystem Investigations,” is held from in June 2008 at Grieg Hall, Bergen, Norway. k ) WGFAST Recommends the following theme sessions for the 2006 Annual Sci-ence Conference: i) Joint FTC-RMC Theme Session on “Quantifying, summariz-ing and integrating total uncertainty in fisheries resource surveys.” Co-Conveners: David Demer, U.S.A.; and Stephen Smith, Canada; ii) Joint FTC/LRC Theme Session on “Spatio-temporal characteristics of fish populations and their environmental forcing functions as components of ecosystem-based as-sessments.” Co-Conveners: François Gerlotto (France), and someone from LRC; and iii) Joint FTC/LRC Theme Session on “Technologies for monitoring fishing activities and observing catch.” Co-Conveners: Bill Karp, USA, and Kjell Nedre-aas, Norway

Report of Working Group on the Establishment of an International Herring Research Scheme

Herring Committee. Contributors: Finn Devold, Ole Johan Østvedt, Olav Dragesund, Oddvar Dahl, O. Aasen

Report of the Workshop on estimation of maturity ogive in Norwegian spring spawning herring (WKHERMAT) [1-3 March 2010 Bergen, Norway]

Cotributors: Knut Korsbrekke, Richard D.M. Nash, Michael Pennigton, Aril Slotte, Erling Kåre Stenevik and Øyvind Tange

Preliminary Report of the International 0-group fish survey in the Barents Sea and adjacent waters August-September 1972

Contributors: T. Monstad, R. Saetre, O. Smedstad, L. Midttun, P. Hognestad, O. Nakke