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MSC - Marine Stewardship Council
Consultation Document – Benthic ImpactsBackground Paper 1: Defining “Habitat”, “Habitat
Structure”, and “Habitat Function”
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Consultation Dates: 20 July-31 August, 2012
MSC Contact: Jodi Bostrom <[email protected]>
Purpose
The purpose of this paper is to recommend changes to the MSC Certification Requirements
(CR) and Guidance to the CR (GCR) for comment during stakeholder consultation.
Introduction
The MSC asked a team of consultants to prepare a report on the global best practices for
managing, measuring, and mitigating the impacts of fishing on benthic habitats (Grieve et al.,
2011). One of the findings from this report is that the MSC does not clearly define the terms
“habitat”, “habitat structure”, and “habitat role”, despite the use of these terms in the Habitats
Performance Indicators (PIs) language. This, therefore, could be an issue when trying to
ensure consistent and robust assessments. Following the Grieve et al. (2011) finding, the
MSC drafted definitions for those three terms and provided them for feedback at the March
stakeholder workshop and the March to April public consultation.
Key Points from Grieve et al. (2011)
For its Risk-Based Framework (RBF) in the GCR, the MSC uses the Substratum,
Geomorphology, and Fauna (SGF) method to identify the benthic habitat units being
assessed. Substratum refers to sediment type, geomorphology to the seafloor topography,
and fauna to the dominant faunal group.
“The SGF implies that the habitat includes the organisms living therein. However,
while habitat refers to an area inhabited by a particular organism, a biotope refers to
both the habitat and its associated species (Costello, 2009). Often a species and a
habitat are indistinguishable (e.g., coral reefs and other biogenic structures) and are
at the very least dependent” (Grieve et al., 2011).
Grieve et al. (2011) proposed the following definition for “habitat”:
“…the chemical and bio-physical environment where an organism resides. The basic
units are pelagic habitats (the water column) or benthic habitats (the seafloor
structure including attached flora and invertebrate fauna)”.
In relation to benthic habitat particularly, the consultants pointed out that attached flora (and
fauna) can have important habitat-forming or functional properties that may be impacted
significantly by fishing. The consultants suggested that the above proposed definition
offered a practical definition of habitats that is consistent with that which appears in the RBF
sections of the CR and GCR (Grieve et al., 2011).
Grieve et al. (2011) suggested that “habitat structure” is the amount, composition, and threedimensional arrangement of biological and physical matter in an area, providing refuge and
surface area for food production within a marine ecosystem (after Warfe and Barmuta, 2004).
In simpler terms, habitat structure is the physical arrangement of matter that supports plant
and animal life (ibid).
Based on Warfe and Barmuta (2004), an applicable definition for “habitat role” might be “the
range of services provided to an organism or ecosystem, including, but not limited to,
FOR CONSULTATION -20th JULY-31st AUGUST 2012
mediating trophic interactions between predator and prey and between predators, providing
refugia, and influencing behaviour of organisms” (Grieve et al., 2011).
“For example, seagrasses or mangroves may provide predator refuge, whilst
adjacent soft-bottom environments may provide foraging opportunities. It is
important to note that these services may be life-stage and size dependent and can
change according to the density of biotic and abiotic physical matter within the habitat
structure itself” (Grieve et al., 2011).
Original Proposed Definitions
The following definitions were proposed for discussion at the March workshop and for
consideration during the subsequent consultation period:
 Habitat is the chemical and bio-physical area where an organism lives, which may
include attached flora or fauna such as (but not limited to) corals or seagrasses and
other attached non-target species.
 Habitat structure is the arrangement of physical structures that support plant and
animal communities.
 Habitat role is the range of services provided to an organism, including, but not
limited to, mediating trophic interactions between predators and predators and prey,
providing refuge, and influencing the behaviour of organisms.
Comments from First Stakeholder Workshop and Public Consultation
Habitat
The workshop attendees generally felt that the proposed definition for “habitat” was good,
but some felt that oceanographic dynamics should be recognised and included, as well as
habitat-forming flora, redrafting to something like:
“The chemical, bio-physical, oceanographic conditions including associated habitat-forming
flora and fauna where target organism exists.”
Others felt that the proposed “habitat” definition was organism-centric and scale dependent
and contrasts with the SGF approach used in the RBF. They suggested that the definition’s
starting point should be the SGF approach, but include flora, given the MSC’s potential
implementation of a default RBF-like process. These sentiments were echoed in a comment
received during public consultation. It was also noted that it would be helpful if the definition
clarified whether or not fauna is in reference to sessile habitat forming species only.
However, expressing concern that revised definitions could add unnecessary complexity,
another public consultation comment suggested the following definition:
“Habitat is an area with similar chemical and bio-physical characteristics.”
Habitat Structure and Habitat Function
Some workshop attendees stated that the proposed definition for “habitat structure” was
acceptable but wondered if defining “habitat role” was necessary. A public consultation
comment voiced the opinion that “habitat structure” is the more important term. Workshop
attendees and public consultation comments also noted that there are inconsistencies
between the use of “function” and “role” within the PI language that need to be addressed.
Technical Advisory Board Working Group Discussion
Consultation Document – Benthic Impacts: Background Paper 1: Defining “Habitat”, “Habitat Structure”, and
“Habitat Function”
FOR CONSULTATION -20th JULY-31st AUGUST 2012
During the May Technical Advisory Board (TAB) working group meeting, the group
discussed the outcomes and comments from the stakeholder workshop and public
consultation in some detail. The TAB proposed some wording changes to the definitions in
preparation for the second public consultation.
Recommendations
New Proposed Definitions and CR and GCR Changes
Based on the above information, the MSC is recommending the definitions and changes to
the CR and GCR as outlined below in Appendix 1. In short, the MSC is recommending a
definition for “habitat” that attempts to incorporate as many of the stakeholder views as
possible while reducing complexity and is recommending definitions for “habitat structure”
and “habitat function” since both of these terms appear in the PI language. Additionally, it is
recommended that all instances of “habitat role” be changed to “habitat function” (in line with
the terminology of the PI language) to decrease confusion and increase consistency.
References
Costello, M.J. 2009. Distinguishing marine habitat classification concepts for ecological
data management. Marine Ecology Progress Series 397:253-268.
Grieve, C., D.C. Brady, and H. Polet. 2011. Best Practices for Managing, Measuring, and
Mitigating the Benthic Impacts of Fishing: Final Report to the Marine Stewardship
Council. Unpublished work.
Warfe, D.M. and L.A. Barmuta. 2004. Habitat structural complexity mediates the foraging
success of multiple predator species. Oecologia 141:171-178.
Consultation Document – Benthic Impacts: Background Paper 1: Defining “Habitat”, “Habitat Structure”, and
“Habitat Function”
FOR CONSULTATION -20th JULY-31st AUGUST 2012
Appendix 1
Certification Requirements
CB3.14
Habitats Outcome PI (PI 2.4.1)◙
Table CB17: PI2.4.1 Habitats outcome PISGs
Component
Habitats
PI
Outcome
Status
Scoring
issues
a. Habitat
status
2.4.1
The fishery
does not
cause serious
or irreversible
harm to
habitat
structure,
considered on
a regional or
bioregional
basis, and
function.
SG60
The fishery is
unlikely to
reduce habitat
structure and
function to a
point where
there would be
serious or
irreversible
harm.
SG80
SG100
The fishery is
highly unlikely
to reduce
habitat structure
and function to
a point where
there would be
serious or
irreversible
harm.
There is
evidence that
the fishery is
highly unlikely
to reduce
habitat structure
and function to
a point where
there would be
serious or
irreversible
harm.
CB3.14.1
The team shall assess the habitats component in relation to the effects of the fishery on
the structure and rolefunction of the habitats impacted by the fishery. ◙
CB3.14.2
The team shall use these interpretations:◙
CB3.14.2.1 Serious harm means gross change in habitat types or abundances, and disruption of
the functionrole of the habitats.
CB3.14.2.2 Irreversibility means changes that are expected to take much longer to recover than
the dynamics in un-fished situations would imply, some sort of regime change is
implied from which recovery may not automatically occur.
CB3.14.3
The team shall consider the full extent of the habitats when assessing the status of
habitats and the impacts of fishing, and not just the part of the habitats that overlap with
the fishery. ◙
CB3.14.4
The team should score the fishery at SG100 if evidence shows that the fishery has no
impact on habitats.
CB3.14.5
The team shall interpret the terms ”unlikely”, ”highly unlikely” and ”evidence for” in SG60,
SG80 and SG100 as in Table CB18.
Guidance to the Certification Requirements
GCB3.14
Habitats Outcome PI (PI 2.4.1)
GCB3.14.1 Guidance to Annex CB clause CB3.14.1.
Usually habitats impacted by the fishery are bottom habitats rather than pelagic habitats,
but impacts on the biotic aspects of pelagic habitats could be considered. If a benthic
habitat is being assessed, the team may consider the following points:
Consultation Document – Benthic Impacts: Background Paper 1: Defining “Habitat”, “Habitat Structure”, and
“Habitat Function”
FOR CONSULTATION -20th JULY-31st AUGUST 2012
a.
b.
a.c.
Substratum – sediment type (e.g., hard substrate)
Geomorphology – seafloor topography (e.g., flat rocky terrace)
Biota – dominant floral and/or faunal group(s) (e.g., kelp forest and mixed
epifauna, respectively)
While the productivity and regenerative ability of biogenic habitats would affect their
resilience under fishing, and may be useful surrogates for consideration of status and
reversibility, it is the ecological rolefunction of the habitat and the ecosystem services
that it provides that is the intent of assessment.
a.
For example particular habitats may determine the carrying capacity of target,
bycatch or ETP species, and a mosaic of habitats may be necessary for some
species to complete their life cycle or determine the overall composition of the
ecological community.
GCB3.14.2 Guidance to Annex CB clause CB3.14.2.
Examples of serious or irreversible harm include the loss (extinction) of habitat types,
depletion of key habitat forming species or associated species to the extent that they
meet criteria for high risk of extinction, and significant alteration of habitat cover/mosaic
that causes major change in the structure or diversity of the associated species
assemblages.
GCB3.14.3 Guidance to Annex CB clause CB3.14.3.
For example if a habitat extends beyond the area fished then the full range of the habitat
should be considered when evaluating the effects of the fishery. The ‘full range’ of a
habitat shall include areas that may be spatially disconnected from the area affected by
the fishery and may include both pristine areas and areas affected by other fisheries.
GCB3.14.4 Knowledge of the structure and rolefunction of habitats is often limited, and there is not
general or widespread agreement on the equivalence of targets and limits for fishery
impacts.
Annex AA
AA3
Vocabulary
Term
Habitat
Habitat Structure
Habitat Function
Definition
The chemical, bio-physical environment
including biogenic structures where fishing
takes place.
The arrangement of physical, biogenic
formations that support plant and animal
communities.
The range of services provided to an
organism, including, but not limited to,
mediating trophic interactions,
reproduction, shelter, and feeding, and
influencing the behaviour of organisms.
Consultation Document – Benthic Impacts: Background Paper 1: Defining “Habitat”, “Habitat Structure”, and
“Habitat Function”