Managing fisheries to conserve ground fish and benthic invertebrate species diversity' :

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Managing fisheries to conserve ground fish and
benthic invertebrate species diversity.

• MAFCONS

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Mafcons project

• EC financed project
• Partners University of Wales Swansea
• Fisheries Research
  Services (Scotland)
• RIVO
• Ghent University
• Forshungsinstitut
  Senckenberg (Germany)
• Institute for Sea
  Fisheries
• Institute of Marine
  Research ( Norway)
• Workshop 6 January 2003
• First steps and
  Methodology

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Objectives

• Provide a framework that links the respons of
  fish and benthic communities, expressed in terms
  of changes in species diversity, to variation in
  fishing disturbance.
• For it an ecological theory is needed that uses
  these relevant variables and enables the
  ecosystem consequences of fisheries managment
  actions to be predicted and quantified.

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Hustons Dynamic equilibrium model.

• Huston uses two unimodal relationships concerning
  species diversity that are known from theoretical
  ecology. diversity-disturbance /
  diversity-productivity

• He created a new model that combines these two
  relationships and related the species
  diversity simultaneously to both productivity and
  disturbance.

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This model expresses that the relationship
between disturbance and diversity is depending on
the level of productivity.
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Disturbance

• Workshop in Aberdeen May 2003
• Changes in Disturbance mortality
  associated with a specific level of fishing
  effort
• workshop in Wilhelmshaven february
  04 acces and processing of effort
  data
• Fish landed and discarded data
• Benthic species mortality in towpath
• of fishinggear data from
• Cost-Impact project

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Diversity and Productivity

• Collecting the data for productivity and
  diversity estimation by the ICES rectangle
  each partner approx. 23 stations
• Coinciding the yearly IBTS survey
• Fish data 8 and 2 m beam trawl
• Infauna data Van Veen grab
• sediment data core
• Epifauna data 2m beam trawl
  (mesh size 2mm knot to knot)
• Vessel Tridens

Tridens in Aberdeen
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North sea stations sampled during the IBTS survey
18 August-18 September

• stations where Van Veen Grab, 2 m and 8m
  Beamtrawl were used

• stations where 8m beamtrawl was used

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IBTS survey 8m beamtrawl, benthos and groundfish
sampling
port 8 m beamtrawl
Beamtrawl frame
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Catch 8 m beamtrawl
Melanogrammus aeglefinus Haddock
Raja naevus Cuckoos ray
Lophius piscatorius Angler, Monk
Cyclopterus lumpus Lumpsucker
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Porania pulvillus
Psolus phantapus
Lithodes maja
Pecten maximus
Actinauge richardi
Eledone cirrhosa
Pycnogonum littorale
Nephrops norvegicus
Echinus spec.
Loligo forbesi
Scaphander lignarius
Epimeria cornigera
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Van Veen Grab Infauna sampling
Sampling proces
Wilson autosiever sievetower with 1mm and 0.250
mm sieve
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Groundfish

• Diversity 2m beam trawl and 8 m beam
  trawl species determination on board
• Productivity information from IBTS survey

Wet weight (blotted) five animals per species
(individual weight) Measuring
species Length frequency distribution Length/weigh
t relationships
Data processed during campaign.
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Epifauna

• Diversity 5 mm sieve species
  diversity
• 2mm sieve
  diversity at Phylum level
  
• Spatial productivity (ICES rectangle)
• Wet weight
  (blotted) five animals per species
  (individual weight)
• Measuring
  species
• Length frequency distribution
• 
  Length/weight relationships

The 5 mm sieve was analysed on board, the 2mm
sieve is processed by RIVO (IJmuiden)
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Infauna

• Diversity 4-2-1 mm sieves species
  diversity
• 500-250µm sieves diversity at a
  higher level according to Brey
• Spatial productivity (ICES rectangle)
• Using the sieves as
  different size classes
• Wet weight (blotted)
  per species per size class ( 4
  -2-1 mm) per Brey level ( 0.5-0.25mm)
• Conversion to dry
  weight
•     Edgars method (1990)
• Brey uses this breakdown of
  taxa for his wet weight dry weight conversion
  factors.

All in the lab
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Edgar 1990, Use of the size structure of benthic
macrofaunal communities to estimate faunal
biomass and secundairy productivity.
J.Ex.Ma.Biol.
Ecol 137195-214

• Production the mean
  ash-free dry weight of animals
  retained by
  sieves of differing mesh size
• 
  ( 4-2-1-0.5-0.25mm)
• 
  the abundances of animals
• 
  in different sieve size classes
• Equation P 0.0049 B0.80 T0.89
• P (µg day-1) macrobenthic production
• B (µg) ash-free dry weight
• T (C) water temperature

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Past
Future
4mm-2mm-1mm sieves

• Diversity determination
  
• Productivity blotted wet weight
• Sedimentsamples

• Diversity determination
  
• Productivity blotted wet weight
• Sedimentsamples groups
• (as i dont want to call it pakketjes)

55 samples
45 samples
15 samples
85 samples
two
three groups
500µm-250µm sieves
Workshop Wilhelmshaven february 2004
o.a.Problems picking animals out of 2-7litres of
sediment
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