Selecting MPAs to conserve groundfish biodiversity: the consequences of failing to account for catchability in survey trawls

Abstract Fraser, H. M., Greenstreet, S. P. R., and Piet, G. J. 2009. Selecting MPAs to conserve groundfish biodiversity: the consequences of failing to account for catchability in survey trawls. – ICES Journal of Marine Science, 66: 82–89. Fishing has affected North Sea groundfish species diversity. Defining Marine Protected Areas (MPAs) to address this will rely on groundfish surveys. Species-specific catch efficiencies vary between trawl gears, and apparent species diversity distributions are influenced by the type of gear used in each survey. It may be that no single survey depicts actual diversity distributions. Two MPA scenarios designed to protect groundfish species diversity are described, the first based on unadjusted International Bottom Trawl Survey data and the second based on the same data adjusted to take account of catchability. Spatial overlap between these scenarios is low. Assuming that the adjusted data best describe the actual species diversity distribution, the level of diversity safeguarded by MPAs, based on unadjusted data, is determined. A fishing effort redistribution model is used to estimate the increase in fishing activity that is likely to occur in MPAs that take catchability into account, if closed areas based solely on the unadjusted groundfish data were implemented. Our results highlight the need to take survey-gear catchability into account when designating MPAs to address fish-species diversity issues.

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The impact of marine protected areas on temporal stability of fish species diversity

Conservation Biology ◽

10.1111/cobi.13815 ◽

2021 ◽

Author(s):

Amanda K. Pettersen ◽

Ezequiel M. Marzinelli ◽

Peter Steinberg ◽

Melinda A. Coleman

Keyword(s):

Species Diversity ◽

Protected Areas ◽

Fish Species ◽

Marine Protected Areas ◽

Temporal Stability ◽

The Impact ◽

Fish Species Diversity

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Do Norway pout (Trisopterus esmarkii) die from spawning stress? Mortality of Norway pout in relation to growth, sexual maturity, and density in the North Sea, Skagerrak, and Kattegat

ICES Journal of Marine Science ◽

10.1093/icesjms/fss001 ◽

2012 ◽

Vol 69 (2) ◽

pp. 197-207 ◽

Cited By ~ 8

Author(s):

J. Rasmus Nielsen ◽

Gwladys Lambert ◽

Francois Bastardie ◽

Henrik Sparholt ◽

Morten Vinther

Keyword(s):

North Sea ◽

Sexual Maturity ◽

Life History Traits ◽

Trawl Survey ◽

Older Individuals ◽

Fishing Activity ◽

The North ◽

Spawning Areas ◽

The North Sea ◽

New Evidence

Abstract Nielsen, J. R., Lambert, G., Bastardie, F., Sparholt, H., and Vinther, M. 2012. Do Norway pout (Trisopterus esmarkii) die from spawning stress? Mortality of Norway pout in relation to growth, sexual maturity, and density in the North Sea, Skagerrak, and Kattegat. – ICES Journal of Marine Science, 69: 197–207. The mortality patterns of Norway pout (NP) are not well understood. It has been suggested that NP undergo heavy spawning mortality, and this paper summarizes and provides new evidence in support of this hypothesis. The very low–absent fishing activity in recent years provides a unique opportunity to analyse the natural life-history traits of cohorts in the NP stock in the North Sea. Based on the ICES trawl survey abundance indices, cohort mortality is found to significantly increase with age. We argue that this cannot be explained by selectiveness in the fishery, potential size-specific migrations out of the area, higher predation pressure on older individuals, or differences in survey catchability by NP age from before to after spawning and that it is higher in the main spawning areas than outside. We found that natural mortality (M) is significantly correlated with sexual maturity, sex, growth, and intraspecific stock density. All of this is consistent with a greater mortality occurring mainly from the first to the second quarter of the year, i.e. spawning mortality, which is discussed as being a major direct and indirect cause of stock mortality.

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Spatiotemporal variation among demersal ichthyofauna in a subtropical estuary bordering World Heritage-listed and marine protected areas: implications for resource management

Marine and Freshwater Research ◽

10.1071/mf15345 ◽

2017 ◽

Vol 68 (4) ◽

pp. 703 ◽

Cited By ~ 5

Author(s):

Fernanda E. Possatto ◽

Matt K. Broadhurst ◽

Charles A. Gray ◽

Henry L. Spach ◽

Marcelo R. Lamour

Keyword(s):

Marine Protected Areas ◽

Fishing Effort ◽

Spatiotemporal Variation ◽

South American ◽

Important Species ◽

Prey Preferences ◽

Subtropical Estuary ◽

Species Specific ◽

Total Species ◽

Trawl Surveys

Benthic trawl surveys were performed to quantify the spatiotemporal distributions of teleosts and key abiotic associations throughout an ecologically important estuary within Brazil’s Atlantic Forest biosphere. Approximately 52000 fish (51% juveniles) representing 75 species were sampled, with residents accounting for 36 and 61% of total species and individuals respectively. Five artisanally important species comprised 77 and 81% of individuals and biomass respectively. Cathorops spixii was most abundant (>40% of total), whereas Stellifer rastrifer, Aspistor luniscutis, Sphoeroides greeleyi and S. testudineus collectively contributed towards 37 and 34% of individuals and biomass respectively. The abundance of A. luniscutis, C. spixii and S. rastrifer was negatively associated with salinity, whereas the presence of the latter two species was also positively associated with temperature, and S. greeleyi and S. testudineus (mostly adults) were more abundant in deeper areas. These relationships seemed to be affected by species-specific reproductive (S. rastrifer, C. spixii and A. luniscutis), habitat (S. greeleyi and S. testudineus) and prey preferences (juvenile C. spixii and A. luniscutis). Protection for these various species may be achieved via immediate fishing effort regulations, but more research is required to manage other anthropogenic effects. Such work should be a priority to ultimately preserve what is one of the most important South American biodiversity areas.

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Using MPAs to address regional-scale ecological objectives in the North Sea: modelling the effects of fishing effort displacement

ICES Journal of Marine Science ◽

10.1093/icesjms/fsn214 ◽

2009 ◽

Vol 66 (1) ◽

pp. 90-100 ◽

Cited By ~ 38

Author(s):

Simon P. R. Greenstreet ◽

Helen M. Fraser ◽

Gerjan J. Piet

Keyword(s):

Species Diversity ◽

North Sea ◽

Benthic Invertebrates ◽

Regional Scale ◽

Fishing Effort ◽

Fishing Mortality ◽

Total Allowable Catch ◽

The North ◽

The North Sea ◽

Ecological Objectives

Abstract Greenstreet, S. P. R., Fraser, H. M., and Piet, G. J. 2009. Using MPAs to address regional-scale ecological objectives in the North Sea: modelling the effects of fishing effort displacement. – ICES Journal of Marine Science, 66: 90–100. The use of Marine Protected Areas (MPAs) to address regional-scale objectives as part of an ecosystem approach to management in the North Sea is examined. Ensuring that displacement of fishing activity does not negate the ecological benefits gained from MPAs is a major concern. Two scenarios are considered: using MPAs to safeguard important areas for groundfish species diversity and using them to reduce fishing impacts on benthic invertebrates. Appropriate MPAs were identified using benthic invertebrate and fish abundance data. Fishing effort redistribution was modelled using international landings and fishing effort data. Closing 7.7% of the North Sea to protect groundfish species diversity increased the fishing impact on benthic invertebrates. Closing 7.3% of the North Sea specifically to protect benthic invertebrates reduced fishing mortality by just 1.7–3.8%, but when combined with appropriate reductions in total allowable catch (TAC), 16.2–17.4% reductions in fishing mortality were achieved. MPAs on their own are unlikely to achieve significant regional-scale ecosystem benefits, because local gains are largely negated by fishing effort displacement into the remainder of the North Sea. However, in combination with appropriate TAC reductions, the effectiveness of MPAs may be enhanced.

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Mapping spatial variation in demersal fish species diversity and composition in the North Sea: accounting for species- and size-related catchability in survey trawls

ICES Journal of Marine Science ◽

10.1093/icesjms/fsn036 ◽

2008 ◽

Vol 65 (4) ◽

pp. 531-538 ◽

Cited By ~ 26

Author(s):

Helen M. Fraser ◽

Simon P. R. Greenstreet ◽

Rob J. Fryer ◽

Gerjan J. Piet

Keyword(s):

Species Diversity ◽

Spatial Variation ◽

North Sea ◽

Fish Species ◽

Environmental Parameters ◽

Demersal Fish ◽

Marine Biodiversity ◽

The North ◽

The North Sea ◽

Fish Species Diversity

Abstract Fraser, H. M., Greenstreet, S. P. R., Fryer, R. J., and Piet, G. J. 2008. Mapping spatial variation in demersal fish species diversity and composition in the North Sea: accounting for species- and size-related catchability in survey trawls. – ICES Journal of Marine Science, 65: 531–538. The paper maps spatial patterns of groundfish species diversity. It considers how the catchability of different fish species in two different types of bottom trawls, the IBTS GOV and the 8-m beam trawl, influences the estimates of species diversity. Maps of groundfish species diversity derived from these two survey trawls are compared to determine the extent to which the maps of spatial variation in groundfish species diversity are influenced by gear type. Catchability-at-length coefficients were applied to the IBTS data to raise the observed catches to estimates of “actual” numbers of fish present in the path of the trawl, which are then used to produce maps of “actual” species diversity across the North Sea. Finally, these raised maps of “actual” groundfish species diversity are shown to be more explainable based on physical environmental parameters such as depth. We suggest that species diversity maps that take account of catchability provide more reliable information on which to base management decisions than “gear-biased” views. The implications for management are discussed, with particular emphasis on using closed areas to conserve marine biodiversity.

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Evidence from survey data for regional variability in cod dynamics in the North Sea and West of Scotland

ICES Journal of Marine Science ◽

10.1093/icesjms/fsm192 ◽

2008 ◽

Vol 65 (2) ◽

pp. 206-215 ◽

Cited By ~ 22

Author(s):

Steven J. Holmes ◽

Peter J. Wright ◽

Robert J. Fryer

Keyword(s):

Survey Data ◽

North Sea ◽

Gadus Morhua ◽

Temporal Trends ◽

Trawl Survey ◽

Regional Variability ◽

The North ◽

Spawning Areas ◽

General Decline ◽

The North Sea

Abstract Holmes, S. J., Wright, P. J., and Fryer, R. J. 2008. Evidence from survey data for regional variability in cod dynamics in the North Sea and West of Scotland. – ICES Journal of Marine Science, 65: 206–215. Although cod (Gadus morhua) in the North Sea and ICES Division VIa are assessed as single units, recent research suggests that the stocks consist of reproductively isolated subpopulations within a metapopulation. We investigate whether temporal trends in stock indicators are asynchronous across subpopulations, which would support the metapopulation hypothesis. First quarter trawl survey data for the years 1983–2005 were aggregated into putative areas of high spawner fidelity (three in VIa, seven in the North Sea) to obtain indices of spawning–stock biomass (SSB) and recruitment (numbers-at-age 1). Asynchrony was investigated by fitting a smoother to the data for each of the ten spawning areas and testing whether the smoothers were parallel. Trends in SSB differed between spawning areas in both VIa and the North Sea. In VIa, SSB collapsed in the most southwesterly area, but remained more constant elsewhere. In the North Sea, there was a general decline in SSB, but areas thought to contain resident inshore populations showed more rapid declines than those in adjacent offshore areas. Recruitment results offered less support for a metapopulation, although recruitment in the southern North Sea declined rapidly before any trend was seen for the North Sea as a whole.

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Biology and Management of Dogfish Sharks

Biology and Management of Dogfish Sharks ◽

10.47886/9781934874073.ch10 ◽

2009 ◽

Keyword(s):

Survey Data ◽

North Pacific ◽

Fishery Management ◽

Gulf Of Alaska ◽

Spiny Dogfish ◽

Trawl Survey ◽

Fisheries Science ◽

The North ◽

Abstract Data ◽

Species Specific

Abstract.—Data from research surveys conducted by the National Marine Fisheries Service’s (NMFS) Alaska Fisheries Science Center and the International Pacific Halibut Commission (IPHC) were examined along with catch data from NMFS’s North Pacific Groundfish Observer Program to determine the distribution, abundance, and status of spiny dogfish <em>Squalus acanthias </em>in Alaska. Dogfish are present in the Gulf of Alaska, Bering Sea, and Aleutian Islands but survey and observer data indicate they are most abundant in the central and eastern Gulf of Alaska in waters less than 200 m deep. All data sources indicate that dogfish have increased in abundance in the Gulf of Alaska in recent years. Log-transformed catch per unit effort (CPUE) of dogfish calculated from the NMFS trawl survey data ranged from 0.47 sharks/km2 in 1984 to 0.91 sharks/km2 in 2007, with a peak of 1.17 sharks/km2 in 2003. Log-transformed CPUE of spiny dogfish calculated from the NMFS longline survey data ranged from 0.041 sharks/100 hooks in 1979 to 0.16 sharks/100 hooks in 2007, with peaks in abundance of 0.23 sharks/100 hooks in 1983 and 1998. Log-transformed CPUE of dogfish calculated from the IPHC annual longline survey data showed a similar trend and ranged from 0.84 sharks/100 hooks in 1997 to 1.18 sharks/100 hooks in 2006, with a peak value of 1.38 sharks/100 hooks in 2003. Estimates of the incidental catch of dogfish by Alaska fisheries in the Gulf of Alaska calculated from NMFS observer data from 1990 to 2007 were variable and ranged from 140 to 865 metric tons (mt), with peak values of over 650 mt in years 1998, 1999, 2006, and 2007. Dogfish are currently managed as a member of the “other species” complex by the North Pacific Fishery Management Council in Alaska waters. The increasing abundance of this species in the Gulf of Alaska in recent years and the increasing probability of a fishery developing may necessitate a species-specific management strategy for dogfish in Alaska waters.

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