MEASO Biota Assessment pages should be titled: MEASO Biota: Species name/group The purpose of these assessment pages is to summarise basic information for a species or taxonomic group and how the status and ecology of the group may be changing over time (link here to the framework for assessing biota within the MEASO framework):
Authors are encouraged to use the spatial partitioning of the marine ecosystem assessment (sectors etc - link here), as well as circumpolar information where available. Assessments of change can include, where possible, historical change, current trends and prognoses for future change. Generalities should be avoided and, instead, replaced with specific quantities of change and parameters, including error/uncertainty. Qualitative statements are acceptable provided the reasons for the qualitative conclusions are given, along with the scope for the application of the statements, and the uncertainty surrounding them. In the case of Parameter Tables, authors are asked to include estimates of parameters and their error, wherever possible. Delete parameters that are not relevant. Add parameters that are relevant but not included in the tables. The reference/s estimating the parameters should be cited, along with any statements as to the maturity of the estimates if known (e.g. under development, personal communications, future work is examining.....). For some species, life history information and parameters are co-opted from areas outside of the subject area, e.g. from outside the Southern Ocean. This proxy information is reasonable to include. Please include also the rationale for co-opting these data, and citations. Biota pages need to be written concisely, well-referenced, and using the uncertainty language of the IPCC. In the first instance, references can be from peer-reviewed literature, reports that are publicly available or references in the grey literature that could be obtained from repositories. If the information is known but the references cannot be sourced in the first instance that put a placeholder for filling in the citation. This is useful for translating common ideas into this assessment without worrying about the pedigree of the idea in the first instance. Under each heading is a list of information (in red italics) that is desirable for that section. Please do not change these main headings. If needed, a section can be further subdivided. Please delete the red italics and the instructions window from the page when it is completed (when the page is in edit mode you can select it for deletion). On photographs, figures and tables: If these are taken from publications or libraries that require recognition of copyright then we need to secure the necessary permissions to include them on these pages. Put a placeholder with a reference to the material and then seek permission for use. Or contact us and we will undertake this process. All materials taken from libraries or references need to be cited appropriately, including photographs and text from web sites. See citation instructions (link here) Other finalised MEASO Biota pages provide good examples of how to populate these assessments. MEASO Assessment pages should be titled: MEASO Biota: Species name/group The purpose of these assessment pages is to summarise basic information for a species or taxonomic group and how the status and ecology of the group may be changing over time (link here to the framework for assessing biota within the MEASO framework). Authors are encouraged to use the partitioning of the marine ecosystem assessment (sectors etc - link here) as well as circumpolar information. Assessments of change can include historical change, current trends and/or prognoses for future change. Ideally, assessments will be quantitative but can include qualitative statements as well. Estimates of error and points of critical uncertainty need to be identified where possible. Final assessments need to be written concisely, well-referenced, and using the uncertainty language of the IPCC. In the first instance, references can be from peer-reviewed literature, reports that are publicly available or references in the grey literature that could be obtained from repositories. Under each heading is a list of information (in red italics) that is desirable for that section. Please do not change these main headings. If needed, a section can be further subdivided. Please delete the red italics and this window from the page when you have completed it (when the page is in edit mode you can select it for deletion). Other finalised MEASO Biota pages provide good examples of how to populate these assessments. |
General description Brief description of the body form and size, recognisable attributes Why do scientists study these organisms and why are they important to the public at large (e.g. important to CCAMLR policy-makers) Why are they included in MEASO? Conspicuous group of zooplanktonic crustaceans and a key prey group in most oceans and seas; neritic and oceanic. This section is devoted information pertaining to species other than the most abundant krill species in the Southern Ocean, Antarctic krill (Euphausia superba), which can be accessed here. Krill are collectively known as Euphausids, and are considered a homogenous taxon exhibiting only slight differences in chomosomal morphology (Thiriot-Quiévreux et al. 1998). Among the 85 species of Euphausiidae distributed globally,
Typical photograph/s |
Summary role in ecosystem
Summary statement of role in ecosystems, global significance and known/expected significance in Southern Ocean
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Summarise the autecology of the group and whether this differs between sectors, and/or over years
Auteology is the ecology of an individual species, and includes its life history, movement, food, energetics, and rate processes. Here we summarise the autecology of the group and whether this differs between sectors, and/or over years.
Include at the beginning a general description of the important features of the group's autecology. As far as possible, include this general detail in figures (rather than text) illustrating the life cycle, phenology (timing of events) and other general attributes. (please put figures in placeholders in the template)
The following sections provide specific estimates/conclusions about how to represent these attributes in models of this group, which may be qualitative network models or dynamic models.
Include in the table only available estimates of life history parameters and their error, wherever possible. Delete parameters that are not relevant. Add parameters that are relevant but not included in the tables. The reference/s estimating the parameters should be cited, along with any statements as to the maturity of the estimates if known (e.g. under development, personal communications, future work is examining.....). For some species, life history information and parameters are co-opted from areas outside of the subject area, e.g. from outside the Southern Ocean. This proxy information is reasonable to include. Please include also the rationale for co-opting these data, and citations. If the parameters are different between locations/sectors then include those differences in the table.
Variable depending on species. See Chapter 5 Population Parameters (Siegel and Nicol) in Everson ed. 2008 Krill: Biology, Ecology and Fisheries. J. Wiley and Sons; also Kawaguchi special volume on krill.
E. superba capable of living to 5+ years in the wild, up to 11 years in captivity. Juvenile at year 1, sub-adult at year two, although some females may be sexually mature, sexually mature at year 3, but both females and males can regress to non-sexual stage.
E. crystallorophias, T. macrua, probably 2-4 years life span.
E. triacantha mainly found below euphotic zone, but can migrate into surface waters. The others are predominantly epipelagic, but can also be found deep.
Parameters | Values | Notes | References |
|---|---|---|---|
Maximum age | T. vicina: max. length: 17 mm | ||
Average adult size | |||
Age at maturity | |||
Size at maturity | |||
Spawning/breeding area | |||
Spawning/breeding season | |||
Larval/gestation period | |||
Location of recruits | |||
Size of recruits | |||
| Overall natural mortality rate | |||
Non-predation natural mortality rates |
Depending on species group - this could be large movements of populations in and out of the region (e.g. whales) or it could detail diurnal vertical migration of fish/plankton species.
Population scale - need to include time of year when migration/movement might be more prevalent. Small scale migration - time of day, depths etc
All euphausiids appear to show diurnal vertical migration (DVM).
Adult females, males and juvenile E. superba may show different DVM patterns. Not clear how much E. crystallorophias vertically migrates. It appears not to migrate into the uppers surface layers because of elevated temperature (surface warming).
E. frigida - performs diel vertical migrations from 250–500 m depth by day to 50 m by night.
E. triacantha - Migrates from 750 m depth at day to 250 m at night but does not form large swarms and is not recorded as prey for whales.
N. megalops - The species performs diel vertical migrations down to 300 m at night.
E. vallentini - Swarming behaviour and diel vertical migrations from 100 m to 250 m depth by day, to near surface waters at night.
Summary dietary information - e.g. "This species feeds predominantly on krill, with a small percentage of it's diet made up of mesopelagic fish species. Winter diets are predominantly fish based and located north of 60degS." Summaries from the Southern Ocean Dietary Database would be useful to include here. If there are variations in diet between sectors or locations then include those differences as well. Also include assessment of change in diet, when available, seasonally and over years. Isotopic or genetic analyses would be useful to include.
Euphausiids have varying levels of omnivory depending on time of year and availability of food.
Many of the other species also eat detritus as well as being omnivores.
E. longirostris - Epipelagic and carnivorous euphausiid, feeds on the copepod Oithona sp.
N. megalops - Carnivorous, feeding preferentially on copepods, Oithona sp.
The Southern Ocean dietary database is a compilation of trophic data from across the Southern Ocean. Data have been drawn from published literature, existing trophic data collections, AADC data sets and unpublished collections. The table below provides a summary of prey items by family (or higher) for Euphausiids (not including Euphausia superba).2 .
FRACTION_DIET_BY_WEIGHT: The fraction (by weight) of the predator diet that this prey type made up (e.g. if Euphausia superba contributed 50% of the total mass of prey items, this value would be 0.5).
FRACTION_DIET_BY_PREY_ITEMS: The fraction (by number) of prey items that this prey type made up (e.g. if 1000 Euphausia superba were found out of a total of 2000 prey items, this value would be 0.5).
FRACTION_OCCURRENCE: The number of times this prey item occurred in a predator sample, as a fraction of the number of non-empty samples (e.g. if Euphausia superba occurred in half of the non-empty stomachs examined, this value would be 0.5). Empty stomachs are ignored for the purposes of calculating fraction of occurrence. For gut content analyses (and any other study types where 'no prey' can occur in a sample), the fraction of empty stomachs is also given (using prey_name 'None' - e.g. if predator_total_count was 10 and 3 stomachs were empty, this will be 0.3).
Note that families listed in the table are only included if the family represents more than 10% of the diet. This restricted value is to avoid "trace" or very small dietary contributions. It can be altered if required.
Include basic estimates for energetic calculations here. If measures of these parameters are available for considering changes over time then this may help identification of system-level change.
The summary table here can have references to more detailed tables compiled from many references etc.
Parameters | |
|---|---|
| Ingestion rate | Insert values and short citations here |
| Metabolism | |
Fecundity | |
Length-weight relationships | |
Growth rate | |
Size at age | |
| Population Productivity (average life time) |
In the introduction to this section, provide a general description of the locations where the group is expected to be found, including depth, proximity to the continent/islands/shelf areas. Also introduce the physical and biological dependencies of the group. e.g. distribution is constrained by the temperature range, or the group is only found in sedimentary environments and so on.
E. crystallorophias - Coastal species found in waters below 0°C and under ice-cover swarms in the top 500 m of the water column on the shelf. Adults restricted to the cold waters of the neritic zone of Antarctic (Hosie 1994a). Unlikely to be found in surface warmed waters, more likely stays below T-min layer. Larvae can be carried off-shore by currents/gyre but probably unlikely to survive.
E. frigida - Species found in waters above 0°C. Species has not been found under pack ice.
Present the relationships between the group and physical and biological environmental attributes. These may be qualitative and/or quantitative relationships, including descriptions/estimates of uncertainties. Justification will be needed for the qualitative relationships. Critical thresholds/ranges/non-linear relationships of the group with habitat variables are important to identify if present, including how they will affect the ecology of the species/group. Express uncertainties in these relationships as confidence intervals, and/or descriptive uncertainties (such as adopted proxies from measurements elsewhere)
Here we ask that you endeavour to characterise the relationships of the taxon with the habitat as a function relationship, i.e. the response of the taxon (life stage)(y-axis) relative to the magnitude of the habitat (x-axis). We provide icons below to paste into the table. If possible, add the values of the parameters of the relationship and detail the uncertainty around them.
Functional responses of taxon (y-axis) to habitat variables (x-axis) are described here (with citations to the evidence). Options for response types may be:
= increase
= threshold then increase
= threshold separating inhospitable habitat (low values) from hospitable habitat (high values)
= gradual decrease
= threshold decrease
= threshold separating hospitable habitat (low values) from inhospitable habitat (high values)
= non linear
(If no image showing type available then please make one).
Parameters for a response type are to be given with their attendant uncertainties/errors/range, with references.
| Variable | Taxon size/stage impacted | Functional response (icon) | Parameters and uncertainties | Risk areas/regions impacted | Notes |
|---|---|---|---|---|---|
Paste icon here | |||||
Placeholder for content, please contact us if you have data or information you would like to contribute to Soki. Summarise the population status, trends and prognoses for the species/group and whether this differs between sectors, and/or over years. Consideration of threshold population sizes, the location of local populations with respect to the range (habitat conditions) etc. will be beneficial.
McLeod et al. (2010) describe a zooplankton atlas of the Southern Ocean developed from the SCAR SO Continuous Plankton Recorder survey (1991-2008). This details the distribution and abundance of the 50 most abundant zooplankton taxa amongst the 200+ taxa sampled. Individual species distribution maps are available from the Australian Antarctic Data Centre.
E.superba – Most abundant euphausiid in relation to biomass, nominally ~200 million tonnes. Evidence from Atkinson et al. (2004) that krill stocks have declined (mainly area 48) in the 70’s. CPR shows perhaps very slight decline between 1990 and 2000 (between 60°E and 160°E), otherwise steady (see individual Antarctic krill profile for further information).
T. macrura – most abundant in terms of numbers, but as a smaller species (~30 mm max length), its biomass is less than E. superba. CPR data show steady decline in adult numbers (between 60°E and 160°E), although there is a corresponding slight increase in furcilia larval stage.
E. crystallorophias – very abundant and dominate species in neritic zone. Their small size (~35 mm max size) compared with E. superba and their restricted geographic distribution means that they are less abundant in relation to numbers and biomass compared to the previous two species. Nonetheless, it is an important prey species in coastal waters.
E. frigida – common species north of the sea-ice zone, but particularly abundant in relation to biomass (small species), third most numerically species in CPR counts after T. macrura and E. superba.
E. vallentini – common species in SAZ and PFZ, notably around HIMI, numerically fourth most common species in CPR.
E. triacantha – frequent in CPR samples, but as a meso-pelagic species it is more common and abundant below the euphotic zone. Its biomass is not well known.
The remaining species have relatively low abundances, most would be classed as rare to low frequency of occurrence.
Distribution and abundance of the population. Consideration of the abundances relative to an assessed range of the species would be beneficial.
Include here
E. crystallorophias - Coastal species with adults restricted to the cold waters of the neritic zone of Antarctic, usually <-1.5 and never north of the continental shelf edge (Hosie 1994a).
E. frigida - More common north of the sea-ice zone, up to the SAF.
E. lucens - Found mostly in the Atlantic, Indian and Pacific Oceans.
E. similis - Distribution extends widely out of the Southern Ocean.
E. similis var. armata - Distributed further North in the Southern Ocean than the typical form.
E. spinifera - Distribution is mostly out of the Southern Ocean.
E. triacantha – Wide circumpolar distribution north of continental shelf and south of SAF, meso-pelagic.
N. megalops - Distribution extends into the Pacific and Indian Ocean and the north Atlantic.
T. gregaria - Mostly found north of the Sub-Antarctic Front (SAF).
T. macrura - Wide, circumpolar distribution from the SAF to the Antarctic coast.
E. vallentini – mainly SAZ and PFZ, but can be found south of PF.
T. vicina - Found within the SO, around the Falkland Islands, South of New Zealand and off Kerguelen Islands.
Others:
Sub-Antarctic/sub-tropical: Euphausia longirostris, Nematoscelis megalops, Euphausia lucens (some specimens south of PF), Euphausia spinifera, Thysanoessa gregaria, Euphausia similis, Euphausia recurva, Euphausia hanseni.
Australian and New Zealand neritic waters: Nyctiphanes australis
Numerous papers on distribution, e.g. Atkinson, Nicol papers, plus CPR atlas for other species (McLeod et al. 2010)
Larvae generally have the same distribution as the adults, but have less mobility. Some species such as T. macrura exhibit very strong latitudinal phenological change in the start of spawning and larval development. Spawning starts earlier in the lower latitudes and northern larvae are more advanced than high latitude larvae (Hosie 1991 and 1994b).
E. superba eggs sink to 1000-2000 m and larvae have deep-water developmental ascent. E. crystallorophias eggs float.
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Assessments of variability, trends over time and prognoses. Analyses of possible links to drivers (habitat, food web) to be included here.
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Synecology refers to the ecology of interactions between species, including food webs (consumers), competition, disease and so on.
Include here, 2-3 sentence summary of the type of interactions with other species. Also describe differences in the relationships between sectors/locations.
2-3 sentence summary of the type of consumers at different times of the year, including evidence of whether these have changed over time.
E. vallentini - Potential prey for small predators.
T. vicina - Prey for whales.
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When known, include this section and present information on direct human impacts on this group. For example, from fisheries, polIution and tthe like.
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Add the following table or simply say 'None of these species has been assessed for the Red List'
| Year of classification: | |
| Red List Category & Criteria: | |
| Assessment Justification: | include description and link to the web site |
Include assessments from other bodies if available.
A list of references referred to on this page.
Please use Ecology style, for more information and examples see:
https://besjournals.onlinelibrary.wiley.com/hub/journal/13652745/author-guidelines
Atkinson, A., Siegel, V., Pakhomov, E., & Rothery, P. (2004). Long-term decline in krill stock and increase in salps within the Southern Ocean. Nature, 432, 100-103.
Hosie, G.W. (1991). Distribution and abundance of euphausiid larvae in the Prydz Bay region, Antarctica (January 1985). Antarctic Science, 3(2),167-180
Hosie, G.W. (1994a). The macrozooplankton communities in the Prydz Bay region, Antarctica. In: S.Z. El-Sayed (Ed.) Southern Ocean Ecology: The BIOMASS Perspective (pp.99-123). Cambridge, UK: Cambridge University Press.
Hosie, G.W. (1994b). Multivariate analyses of the macrozooplankton community and euphausiid larval ecology in the Prydz Bay region, Antarctica. ANARE Reports, 137.
Marchant, H.J., Watanabe, K. & Kawachi, M. (1996). Marine snow in Antarctic coastal waters. Proceedings of the NIPR Symposium on Polar Biology, 9, 75-83.
McLeod, DJ, Hosie, GW, Kitchener, JA, Takahashi, KT, Hunt, BPV (2010) Zooplankton Atlas of the Southern Ocean: The Southern Ocean Continuous Plankton Recorder Survey (1991-2008) Polar Science 4(2): 353-385. doi: 10.1016/j.polar.2010.03.004
Thiriot-Quiévreux et al. 1998
| Name | Affiliation |
|---|---|
| Graham Hosie | AAD |
| So Kawaguchi | AAD |
| Kerrie Swadling | IMAS |
| Madeleine Brasier | IMAS/ACE CRC |
Version number | Date of creation * | Expert reviewers | Peer reviewers | Date of completion* |
|---|---|---|---|---|
| 1.0 | 2019.05.06 | |||
* Date format is YYYY.MM.DD