The FAO deep-sea guidelines recognise that ‘Merely detecting the presence of an element itself is not sufficient to identify a VME’. (FAO 2008, Annex 1). Single encounters with evidence of a VME indicate the presence of a vulnerable species at some point in the area fished during the tow or set, but may not indicate the presence of a vulnerable ecosystem in the area. Further analyses are required to designate areas known to support VMEs based on repetitive encounters with vulnerable species in a particular area, prediction of areas likely to support VMEs based on information on habitat suitability for vulnerable deepwater benthic species, or seabed biodiversity surveys.
While an encounter with evidence of a VME at a single site may not indicate presence of an actual VME, multiple or repetitive encounters with such evidence in an area provide an increasing likelihood that the area does support a benthic VME. Data on evidence of VMEs gathered during fishing operations, and reported to the SPRFMO Secretariat, should be regularly analysed to identify, map and characterise areas in which multiple or repetitive encounters with VME species are found. The following guidelines on what constitutes repetitive encounters with vulnerable taxa indicating presence of a VME are provided by Rogers et al. (2008):
Two or more consecutive hauls containing > 2kgs each of live corals, or > 5kg sponges or other habitat-forming epifauna, on the same trawl track or setting area, or where consecutive trawling tracks or sets intersect.
> 4 encounters of > 2kg of corals, or > 10 encounters of > 2kg of sponges or other habitat-forming epifauna, within an area (1km2) within one year.
> 4 corals per 1000 hooks in a long line fishery within one year within an area (10km2).
> 15% of hauls of any gear within an area (10 - 100km2) containing corals, sponges or other habitat forming epifaunal taxa.
Prediction of Habitat Suitability and Likelihood of VMEs
Data on seabed biodiversity are lacking for most deep sea benthic areas, except for a few specifically surveyed seamount systems, and seabed biodiversity surveys are likely to remain unaffordable for all but a few areas of particular interest. . In the absence of such data, biologically important physical factors (Clark 2008, Penney et al. in press) can be used to indicate suitability of specific areas for vulnerable benthic species, and to stratify measures such as spatial closures to protect such areas. Important seabed characteristics are listed in Section 4.4 - Biologically Important Factors.
Physical seabed factors can be combined with physical / chemical factors such as temperature, salinity, depth, chlorophyll, oxygen, currents, productivity and water chemistry using habitat suitability models and environmental niche factor analysis (Hirzel et al. 2002) to predict suitability of particular areas or features as habitats for VME species. Analyses of this type have been conducted for the South Pacific region by Clark et al. (2006), classifying the original Kitchingman and Lai (2004) seamounts in terms of suitability as habitats for coldwater corals, and by Allain et al. (2008), classifying validated South Pacific seamounts in terms of depth suitability for various deepwater fish species. Taxonomic distinctness indices (Warwick and Clark 1998, Clark and Warwick 1998, 2001) can be used to evaluate comparative uniqueness, and therefore vulnerability, of communities on different features.
In addition to data on interactions with evidence of a VME, SPRFMO participants should collect and contribute data potentially useful to niche factor and habitat suitability analyses to a SPRFMO geospatial database (see Section 9 - Provision of Geospatial Data). These data should be used in periodic analyses coordinated by the SWG to develop habitat suitability indices, predict and map locations of seabed areas with a high likelihood of supporting VMEs in the SPRFMO Area.
The most reliable data on seabed biodiversity and presence of VMEs will be provided by scientific seabed biodiversity surveys, either using seabed sampling equipment designed to quantitatively sample the fauna concerned (such as benthic sampling sleds), or using photographic or video imagery (Constable and Holt 2007, CCAMLR 2007) along planned surveys transects. Where feasible, efforts should be made to conduct such sampling in areas of particular interest or concern, such as those predicted from habitat suitability and niche factor analyses to be highly likely to support VMEs.
Particular efforts should be made to survey areas proposed for long-term and large-scale spatial closures, to ensure that such areas do contain substantial VME communities, and that they are representative (in terms of biodiversity and VME abundance) of areas to be left open to possible fishing. Such surveys could be conducted as internationally collaborative surveys between SPRFMO participants.
Where scientific surveys are not considered to be cost effective, Industry fishing vessels may be suitable platforms for conducting opportunistic seabed imaging using drop cameras or net-mounted video systems. Simultaneous collection of seabed images and benthic bycatch analyses by scientific observers would provide a particularly useful data set for improving understanding of the relationship between seabed biodiversity and benthic bycatches by various fishing gears.
Designation of VME Areas
Information and data on interactions with VME species, predictive analyses of habitat suitability and results of seabed biodiversity surveys should form the basis for mapping and designation of areas known or likely to support VMEs within the SPRFMO Area. The SWG should develop recommendations for measures to protect such areas from significant adverse impacts of bottom fishing. Such recommendations should include recommendations for large-scale permanent spatial closures to protect adequate and representative VME areas from further impact.
When preparing impact assessments for proposed fishing activities, Participants are to specifically take account of all such advice or recommendations on occurrence of areas likely to support VMEs in the SPRFMO Area, and are to detail what management and mitigation measures will be implemented to prevent significant adverse impacts in areas designated as being known or likely to contain VMEs.