A review of the fisheries, life history and stock structure of tropical tuna (skipjack Katsuwonus pelamis, yellowfin Thunnus albacares and bigeye Thunnus obesus) in the Indian Ocean

Probably not a substantial claim: may not pass S2 (checkable).

Understanding life history strategies and stock structure is essential to determine species resilience and how they might respond to exploitation.

“Understanding life history strategies and stock structure is essential to determine species resilience and how they might respond to exploitation.”

• Also stated in: § 1. Introduction · p. 3 · plain

  “Understanding life history strategies and stock structure is essential in determining how a species might respond to fishing pressure”

• cites Jennings et al., 1998 sourceNot checked — no full text of the source
• cites Begg et al., 1999Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

• cites Juan-Jordá et al., 2013 sourcePartly supported

  The Introduction (page unavailable) says life history strategies are fundamental to understanding how species respond to human exploitation, and the Discussion (page unavailable) applies them to management of exploited scombrids. The passages do not establish that understanding stock structure is essential for determining resilience or responses to exploitation. (LLM, conf=0.87)

  Experimental — accuracy not yet measured

May combine two claims.

Tropical tunas are oviparous, have asynchronous oocyte development, and spawn multiple batches of oocytes each spawning season.

“Tropical tunas are oviparous, have an asynchronous oocyte development and spawn multiple batches of oocytes each spawning season (Joseph, 1963; Hunter et al., 1986; Stéquert and Ramcharrun, 1995; Schaefer, 2001).”

• cites Joseph, 1963Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

• cites Hunter et al., 1986Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

• cites Stéquert and Ramcharrun, 1995 sourcePartly supported

  In “Structure de la gonade” (page unavailable), the paper describes skipjack ovaries containing oocytes at different developmental stages. In “Fréquence de ponte des individus” (page unavailable), it infers repeated egg releases during a spawning period, but presents that inference cautiously. The findings concern western Indian Ocean skipjack, not tropical tunas generally, and the paper does not explicitly classify them as oviparous. (LLM, conf=0.86)

  Experimental — accuracy not yet measured

May combine two claims.

Koya et al. (2012) observed year-round spawning of skipjack tuna in Indian waters but reported a peak in activity between December-March and a smaller peak from June to August.

“Koya et al., (2012) also observed year-round spawning in Indian waters but reported a peak in activity between December-March and a smaller peak from June to August.”

• cites Koya et al., 2012Supported

May combine two claims.

Genomic analyses have revealed asymmetrical dispersal from the Indian Ocean yellowfin tuna into the Atlantic and highlighted that yellowfin tuna found along all the South African coast are derived from the Indian population.

“Moreover, genomic analyses have revealed asymmetrical dispersal from the Indian Ocean yellowfin tuna into the Atlantic and highlighted that yellowfin tuna found along all the South African coast are derived from the Indian population (Barth et al., 2017; Mullins et al., 2018).”

• cites Barth et al., 2017 sourcePartly supported

  The Discussion section, “Demographic Histories and Asymmetric Gene Flow,” reports migration estimates about ten times higher from the Indo-Pacific to the Atlantic than in the reverse direction. But the Sample Collection section lists only one South African site, Cape Town, and the Results section says all except one of its seven specimens grouped with the Indo-Pacific clade. The paper therefore does not establish that yellowfin tuna along all of South Africa’s coast derive from the Indian population. (LLM, conf=0.89)

  Experimental — accuracy not yet measured
• cites Mullins et al., 2018 sourceSupported

May combine two claims.

Microsatellite loci supported a single worldwide panmictic bigeye tuna population, whereas mitochondrial markers show genetic differentiation between Atlantic and Indo-Pacific bigeye tuna populations.

“Microsatellite loci supported a single worldwide panmictic bigeye tuna population, whereas mitochondrial markers show genetic differentiation between Atlantic and Indo-Pacific bigeye tuna populations, as previous studies did.”

• cites Gonzalez et al., 2008 sourceSupported

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

Skipjack tuna has undergone distribution range reduction in the Indian Ocean, contrary to what occurred in the Pacific Ocean.

“Worm and Tittensor (2011) reported that skipjack tuna has undergone distribution range reduction in the Indian Ocean, contrary to what occurred in the Pacific Ocean.”

• cites Worm and Tittensor (2011) sourceSupported

Probably not a substantial claim: may not pass S4 (based).

High fishing pressure over the past three decades has raised concerns about the sustainability of skipjack, yellowfin and bigeye tuna in the Indian Ocean.

“High fishing pressure over the past three decades has raised concerns about their sustainability.”

Probably not a substantial claim: may not pass S3 (load-bearing).

Mean batch fecundity of bigeye tuna in the western Indian Ocean is estimated at 0.75±0.52 million oocytes.

“Finally, mean batch fecundity of bigeye tuna in the western Indian Ocean has been estimated at 0.75±0.52 million oocytes (Zudaire et al., 2016).”

• cites Zudaire et al., 2016Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

May combine two claims.

The difficulty of monitoring the fisheries within the Indian Ocean not only affects the stock assessment process, but also the implementation of the agreed management measures in the IOTC area.

“The difficulty of monitoring the fisheries within the Indian Ocean not only affects the stock assessment process, but also the implementation of the agreed management measures in the IOTC area.”

Probably not a substantial claim: may not pass S2 (checkable).

Regional stock structure studies indicate that the panmictic population assumption of these stocks should be investigated further.

“regional stock structure studies indicate that the panmictic population assumption of these stocks should be investigated further.”

May combine two claims.

Spatial structure is recognized in current stock assessments, which need to determine relative abundances among regions.

“although spatial structure is recognized in current stock assessments, which need to determine relative abundances among regions”

• cites Hoyle, 2018Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

• cites Hoyle and Langley, 2020 sourceNot checked — no full text of the source

Classified as probably not a substantial claim.

Understanding of stock structure helps determine the appropriate units for stock assessment and suitable spatial scale for management.

“the understanding of stock structure helps determine the appropriate units for stock assessment and suitable spatial scale for management (Kerr et al., 2016)”

• cites Kerr et al., 2016Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

May combine two claims.

In the eastern and west-central Indian Ocean, L50 for female yellowfin tuna has been estimated at 109.6 cm and 114.0 cm respectively, and for males at 104.9 cm and 120.0 cm FL.

“In the eastern and west-central Indian Ocean, L50 for females has been estimated at 109.6 cm and 114.0 cm respectively, whereas L50 reported for males was at 104.9 cm and 120.0 cm FL (Nootmorn et al., 2005; Zhu et al., 2008).”

• cites Nootmorn et al., 2005Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

• cites Zhu et al., 2008 sourceNot checked — no full text of the source

May combine two claims.

Tropical tuna show an indeterminate fecundity type, with oocyte maturation continuous during extended spawning periods.

“Tropical tuna show an indeterminate fecundity type (i.e., oocyte maturation is continuous during their extended spawning periods) (Grande et al., 2012; Zudaire et al., 2013b).”

• cites Grande et al., 2012 sourceNot checked — no full text of the source
• cites Zudaire et al., 2013bNot matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

May combine two claims.

Since 2008, Indian Ocean yellowfin tuna assessments used a spatial stratification, and so did recent bigeye assessments.

“Since 2008, Indian Ocean yellowfin tuna assessments used a spatial stratification (Langley et al., 2008; Fu et al., 2018), and so did recent bigeye assessments (Langley, 2016; Fu, 2019).”

• cites Langley et al., 2008Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

• cites Fu et al., 2018Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

• cites Langley, 2016Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

Classified as probably not a substantial claim.

Each tropical tuna species is considered to form a single stock in the Indian Ocean for management purposes.

“Each tropical tuna species is considered to form a single stock in the Indian Ocean for management purposes”

• cites IOTC, 2017aNot matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

• cites IOTC, 2017bNot matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

• cites IOTC, 2017cNot matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

May combine two claims.

Although catch limitations of yellowfin tuna in the Indian Ocean were agreed due to the overfished status of the stock, the measure failed to achieve its goal as catches has increased by around 9% in 2018 from 2014/2015 levels despite limitations.

“although catch limitations of yellowfin tuna in the Indian Ocean were agreed due to the overfished status of the stock (IOTC Resolution 19/01), the measure failed to achieve its goal as catches has increased by around 9% in 2018 from 2014/2015 levels despite limitations (IOTC, 2019b).”

• cites IOTC, 2019bNot matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

May combine two claims.

In the western Indian Ocean, spawning of skipjack tuna occurs throughout the year, with peaks of intensity between November-March and June-July, coinciding with the northeastern and southwestern monsoon periods respectively.

“In the western Indian Ocean, spawning of skipjack tuna occurs throughout the year, with peaks of intensity between November-March and June-July, coinciding with the northeastern and southwestern monsoon period respectively (Stéquert et al., 2001; Grande et al., 2014).”

• cites Stéquert et al., 2001 sourceNot checked — no full text of the source
• cites Grande et al., 2014 sourceNot checked — no full text of the source

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

Sardenne et al. (2017) suggested an income-capital breeding strategy for bigeye tuna after concluding that liver neutral fatty acids levels were similar to those from yellowfin.

“However, Sardenne et al., 2017 suggested an income-capital breeding strategy for bigeye tuna after concluding that liver neutral fatty acids levels were similar to those from yellowfin.”

• cites Sardenne et al., 2017 sourceNot checked — no full text of the source

May combine two claims.

These models consider spatial differences in catches but assume a single-stock recruitment relationship (i.e. a unique spawning population with no reproductively isolated units).

“These models consider spatial differences in catches but assume a single-stock recruitment relationship (i.e. a unique spawning population with no reproductively isolated units).”

Probably not a substantial claim: may not pass S3 (load-bearing).

Grande et al. (2010) estimated batch fecundity from 100,828 to 627,325 oocytes in female skipjack ranging from 32 to 68 cm FL.

“Grande et al. (2010) estimated batch fecundity from 100,828 oocytes to 627,325 oocytes in female skipjack ranging from 32 to 68 cm FL.”

• cites Grande et al., 2010Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

Probably not a substantial claim: may not pass S2 (checkable).

Scientific evidence on how tropical tuna are structured in the Indian Ocean is required to validate the adequacy of the divisions used in this approach and to resolve the single stock hypothesis assumption, as different scenarios may lead to different management strategies and implications.

“However, scientific evidence on how tropical tuna are structured in the Indian Ocean is required to validate the adequacy of the divisions used in this approach and to resolve the single stock hypothesis assumption, as different scenarios may lead to different management strategies and implications”

Probably not a substantial claim: may not pass S3 (load-bearing).

In the Pacific Ocean, mean spawning interval has been determined as 1.18, 1.53 and 1.09 days for skipjack, yellowfin and bigeye tuna respectively.

“in the Pacific Ocean the mean spawning interval has been determined as 1.18 , 1.53 and 1.09 days for skipjack, yellowfin and bigeye tuna respectively (Schaefer, 2001).”

• cites Schaefer, 2001 sourceNot checked — no full text of the source

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

Proctor et al. (2019) proposed that the observed pattern of differentiation may indicate limited gene flow between the central and eastern Indian Ocean, with more pronounced gene flow among Indonesian and Western Pacific regions.

“Proctor et al. (2019) proposed that the observed pattern of differentiation may indicate limited gene flow between the central and eastern Indian Ocean, with more pronounced gene flow among Indonesian and Western Pacific regions.”

• cites Proctor et al., 2019Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

May combine two claims.

In the eastern Indian Ocean, the spawning season of bigeye tuna is reported from December to January, with another peak in June.

“In the eastern Indian Ocean, the spawning season is reported from December to January, with another peak in June (Nootmorn, 2004), whereas in the western Indian Ocean, high reproductive activity has been observed from January to March (Zudaire et al., 2016).”

• cites Nootmorn, 2004Not checked — no full text of the source

Classified as probably not a substantial claim. May combine two claims.

Current stock assessments are conducted assuming that there are single, Indian-wide stocks of skipjack, yellowfin, and bigeye tuna, and that there is no exchange of fish among Atlantic, Indian and Pacific Oceans.

“Current stock assessments are conducted assuming that there are single, Indianwide stocks of skipjack, yellowfin, and bigeye tuna; and that there is no exchange of fish among Atlantic, Indian and Pacific Oceans.”

Probably not a substantial claim: may not pass S3 (load-bearing).

Morita and Koto (1970) suggested a two-stock structure for Indian Ocean yellowfin tuna, with western and eastern stocks separated approximately at 100°E and possibly mixing in adjacent waters.

“Similarly, analysing Japanese longline fishery data (1961-1965), Morita and Koto, (1970) suggested a twostock structure for the Indian Ocean yellowfin tuna; the western and eastern stocks separated approximately at 100°E and possibly mixing in adjacent waters.”

• cites Morita and Koto, 1970Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

May combine two claims.

Results from genome wide SNPs indicate a marked genetic difference between yellowfin tuna samples from the central Indian Ocean (Maldives) and the western Pacific Ocean, but not between samples from eastern Indian Ocean (Indonesia) and the western Pacific Ocean.

“Results from genome wide SNPs also indicate a marked genetic difference between samples from the central Indian Ocean (Maldives) and the western Pacific Ocean, but not between samples from eastern Indian Ocean (Indonesia) and the western Pacific Ocean (Proctor et al., 2019).”

• cites Proctor et al., 2019Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

May combine two claims.

Yellowfin tuna predominantly spawn from November to February in equatorial waters, primarily on spawning grounds west of 75°E.

“Yellowfin tuna predominantly spawn from November to February in equatorial waters, primarily on spawning grounds west of 75°E (Shung, 1973; Hassani and Stéquert, 1991; Zudaire et al., 2013a).”

• cites Shung, 1973Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

• cites Hassani and Stéquert, 1991Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

• cites Zudaire et al., 2013aNot matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

Probably not a substantial claim: may not pass S3 (load-bearing).

Nishida (1992) concluded that there were two major and two minor stocks of yellowfin tuna in the Indian Ocean, using CPUE, age-specific CPUE and size variations from longline fishery data.

“Later, Nishida (1992) concluded that there were two major and two minor stocks of yellowfin tuna in the Indian Ocean, using catch-per-unit-effort (CPUE), agespecific CPUE and size variations obtained from longline fishery data.”

• cites Nishida, 1992 sourceNot checked — no full text of the source

May combine two claims.

Secondary spawning peaks for yellowfin tuna have been described in June for the western Indian Ocean, between April and June around Sri Lanka, and from October to December off northern Australia and Madagascar.

“Secondary spawning peaks have also been described; in June for the western Indian Ocean, between April and June around Sri Lanka, and from October to December off northern Australia and Madagascar (Stéquert and Marsac, 1989; Stéquert et al., 2001; Zudaire et al., 2013a).”

• cites Stéquert and Marsac, 1989Not checked — no full text of the source
• cites Stéquert et al., 2001 sourceNot checked — no full text of the source
• cites Zudaire et al., 2013aNot matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

May combine two claims.

For bigeye tuna, a single stock was suggested for the Indian Ocean based on distribution, size composition and sexual maturity, although some differences between eastern and western bigeye tuna were reported.

“In the case of the bigeye tuna, a single stock was suggested for the Indian Ocean, based on the distribution, size composition and sexual maturity of the fish, although some differences between eastern and western bigeye tuna were reported (Kume et al., 1971).”

• cites Kume et al., 1971Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

The two major yellowfin tuna stocks were defined at 40°-80°E and 80°-120°E, and the two minor stocks were defined westward 40°E and eastward of 120°E, named far western and far eastern respectively, with the latter possibly being part of the Pacific stock.

“The two major stocks (named western and eastern) were defined at 40°-80°E and 80°-120°E respectively. The two minor stocks were defined westward 40°E and eastward of 120°E, and named far western and far eastern respectively, with the latter possibly being part of the Pacific stock.”

• cites Nishida, 1992 sourceNot checked — no full text of the source

May combine two claims.

This may lead to biased results and data misinterpretation.

“This may lead to biased 615 results and data misinterpretation.”

Probably not a substantial claim: may not pass S4 (based).

There is still not a consensus on spawning time and location of tropical tuna in the Indian Ocean, which is important to inform assumptions about total reproductive output.

“Similarly, there is still not a consensus on spawning time and location of tropical tuna in the Indian Ocean, which is important to inform assumptions about total reproductive output.”

May combine two claims.

Despite rapid movements described for skipjack tuna tagged in the Mozambique Channel, most tagged tuna returned to this area within one year, coinciding with the March-May fishing season, a pattern recurrent over the studied years.

“Despite the rapid movements described for skipjack tuna tagged in the Mozambique Channel, most tagged tuna returned to this area within one year, coinciding with the March-May fishing season, a pattern that was recurrent over the studied years (Fonteneau and Hallier, 2015).”

• cites Fonteneau and Hallier, 2015 sourceNot checked — no full text of the source

May combine two claims.

Results obtained from the RTTP-IO describe fast and large-scale bigeye movements, with an average monthly distance between tagging and recovery positions of 918 miles in the first year, with distances increasing slowly in subsequent years.

“Results obtained from the RTTP-IO also describe fast and large-scale bigeye movements. The average monthly distance between tagging and recovery positions is 918 miles in the first year, with distances increasing slowly in subsequent years (Fonteneau and Hallier, 2015).”

• cites Fonteneau and Hallier, 2015 sourceNot checked — no full text of the source

May combine two claims.

Despite strong evidence of sexual-dimorphism in yellowfin and bigeye tuna growth, which can lead to elevated sex-biased fishing mortality rates, this is not currently being considered in stock assessments due to a lack of the necessary data.

“Despite strong evidence of sexual-dimorphism in yellowfin and bigeye tuna growth (Eveson et al., 2015), which can lead to elevated sex-biased fishing mortality rates, this is not currently being considered in stock assessments due to a lack of the necessary data.”

• cites Eveson et al., 2015 sourceNot checked — no full text of the source

Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing).

Overall, results obtained from the application of a single type of molecular marker should be interpreted with caution.

“Overall, it seems that results obtained from the application of a single type of molecular marker should be interpreted with caution.”

May combine two claims.

Most studies are regionally limited, which impedes a global overview of the complex interaction between the environment and these species and makes it difficult to incorporate life-history parameters at the appropriate scale into stock assessment models.

“Most studies are regionally limited, which impedes a global overview of the complex interaction between the environment and these species and makes it difficult to incorporate life-history parameters at the appropriate scale into stock assessment models.”

May combine two claims.

Very few tags have been returned from the eastern Indian Ocean, which may reflect a lack movement from west to east, but more certainly, this is a consequence of poor reporting rates by longliners operating in the east Indian Ocean.

“For instance 617 very few tags have been returned from the eastern Indian Ocean (Murua et al., 2015), which may reflect a 618 lack movement from west to east, but more certainly, this is a consequence of poor reporting rates by 619 longliners operating in the east Indian Ocean.”

• cites Murua et al., 2015 sourceNot checked — no full text of the source

Probably not a substantial claim: may not pass S3 (load-bearing).

Fonteneau and Hallier (2015) advised that current tagging programs targeting tropical tuna may still not be adequate to estimate the potential stock mixing rates.

“Fonteneau and Hallier (2015) advised that current tagging programs 616 targeting tropical tuna, may still not be adequate to estimate the potential stock mixing rates.”

• cites Fonteneau and Hallier, 2015 sourceNot checked — no full text of the source

May combine two claims.

There are discrepancies regarding the growth and reproduction parameters of skipjack, yellowfin and bigeye tuna in the Indian Ocean, which increases uncertainties in assessments of their status and advice for their management.

“However, there are discrepancies regarding the growth and reproduction parameters of these key species in the Indian Ocean, which increases uncertainties in assessments of their status and advice for their management.”

Probably not a substantial claim: may not pass S3 (load-bearing).

Electronic tags may present a complementary platform to elucidate tropical tuna real movements.

“Electronic tags may present a complementary platform to 621 elucidate tropical tuna real movements.”

May combine two claims.

Conventional tagging studies depend on tag-recapture efforts, and can be sensitive to the distribution of releases and assumptions related to the tagged population (e.g. random selection, independence and complete mixing).

“Conventional tagging studies, however, depend on tag-recapture efforts, and can be sensitive to the 613 distribution of releases and assumptions related to the tagged population (e.g. random selection, 614 independence and complete mixing) (Pollock and Pine, 2007; Berger et al., 2014).”

• cites Pollock and Pine, 2007 sourceNot checked — no full text of the source
• cites Berger et al., 2014Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

May combine two claims.

Skipjack tagged in Tanzania showed the larger and fastest migrations (average distances of 1129 miles after one month at liberty), followed by skipjack tagged in Mozambique Channel (an average of 894 miles travelled).

“Skipjack tagged in Tanzania showed the larger and fastest migrations (e.g. average distances of 1129 miles after one month at liberty), followed by skipjack tagged in Mozambique Channel (an average of 894 miles travelled).”

• cites Fonteneau and Hallier, 2015 sourceNot checked — no full text of the source

Classified as probably not a substantial claim.

Langley and Million (2012) suggested that the 28-29oC SST isotherm may limit the eastward dispersal of the tagged fish.

“Langley and Million (2012) suggested that the 28-29ºC SST isotherm may limit the eastward dispersal of the tagged fish.”

• cites Langley and Million, 2012Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

May combine two claims.

Skipjack tuna have fast growth rates and reach sexual maturity the fastest among three tropical tuna species.

“For example, skipjack tuna have fast growth rates and reach sexual maturity the fastest among three tropical tuna species (Murua et al., 2017)”

• cites Murua et al., 2017 sourceNot checked — no full text of the source

May combine two claims.

A recent study using SNP data proved restricted connectivity between Indian Ocean (central and eastern) and the western Pacific Ocean bigeye tuna, with samples from central Indonesia having limited connectivity also with the previous areas.

“However, a recent study using SNP data proved restricted connectivity between Indian Ocean (central and eastern) and the western Pacific Ocean bigeye tuna, with samples from central Indonesia having limited connectivity also with the previous areas (Proctor et al., 2019).”

• cites Proctor et al., 2019Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

The reported fast and extensive movements of bigeye tuna in the Indian Ocean led to the assumption that its population is highly mobile, supporting the current assumption of a single stock for the Indian Ocean.

“The reported fast and extensive movements of bigeye tuna in the Indian Ocean led to the assumption that its population is highly 611 mobile, supporting the current assumption of a single stock for the Indian Ocean (IOTC, 2017a).”

• cites IOTC, 2017aNot matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

Classified as probably not a substantial claim. May combine two claims.

Growth, mortality and reproduction are determinant factors for population productivity and key variables for stock assessment and management advice.

“Growth, mortality and reproduction are determinant factors for population productivity and, thus, key variables for stock assessment and management advice (Maunder et al., 2015).”

• cites Maunder et al., 2015Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

May combine two claims.

Most studies carried out to describe the structure of bigeye tuna in the Indian Ocean did not observe signs of heterogeneity, supporting the existence of a single panmictic population in this ocean.

“Few studies have been carried out to describe the structure of bigeye tuna in the Indian Ocean. Most of them did not observe signs of heterogeneity, supporting the existence of a single panmictic population in this ocean.”

Probably not a substantial claim: may not pass S2 (checkable).

A holistic study that integrates results gained from several methods including different spatial and temporal scales will be beneficial in defining appropriate units for the management of tropical tuna species in the Indian Ocean.

“Thus, a holistic study that integrates results gained from several methods including different spatial and temporal scales, will be beneficial in defining appropriate units for the management of tropical tuna species in the Indian Ocean.”

Classified as probably not a substantial claim.

Natural markers can contribute valuable insights of population structuring and highlight migration behaviours or population dynamics that might be sufficiently independent to guarantee spatially structured management.

“Therefore, they can contribute valuable insights of population structuring and highlight migration behaviours or population dynamics that might be sufficiently independent to guarantee spatially structured management.”

• AssumptionRests on an assumption: Natural markers such as parasite tags or otolith microchemistry can inform about the degree of connectivity over an ecological time scale (individual life span).
• AssumptionRests on an assumption: Natural markers can provide information on the environmental history experienced by individuals throughout different life stages.