New insights into ocean sunfish (Mola mola) abundance and seasonal distribution in the northeast Atlantic

Breen, Paul P.; Cañadas, Ana; Cadhla, Oliver Ó; Mackey, Mick; Scheidat, Meike; Geelhoed, S.C.V.; Rogan, Emer; Jessopp, Mark

doi:10.1038/s41598-017-02103-6

Cited by 18 publications

(20 citation statements)

References 33 publications

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“…Seasonal migratory movements of M. mola between low (winter) and high (summer) latitudes in the north Atlantic have been described in several studies (e.g. Sims et al 2009;Potter et al 2011;Sousa et al 2016a;Breen et al 2017). It is possible that similar seasonal movements in our study area could have caused an over-or underrepresentation of one or more sunfish species in our longline samples, thereby potentially explaining the surprising paucity of M. mola.…”

Section: Potential Bias In Interpreting Distribution Patternsmentioning

confidence: 55%

Giant jelly eaters on the line: Species distribution and bycatch of three dominant sunfishes in the Southwest Pacific

Nyegaard

Loneragan

Hall

et al. 2018

Estuarine, Coastal and Shelf Science

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The ocean sunfishes have a long and confusing taxonomic legacy, clouding the global zoogeography of each species and hindering fisheries bycatch assessments. The traditional view of Mola mola as the most common sunfish species worldwide is challenged by our findings from Australia and New Zealand, revealing that three large sunfishes, Masturus lanceolatus, Mola alexandrini and Mola tecta, dominate the tropical/subtropical, warm-temperate and coldtemperate waters here, respectively, while Mola mola-both Pacific and Atlantic clades-is relatively rare. These findings were based on phylogenetic (mtDNA D-loop) and/or morphological species identification of sunfish from longline bycatches (n = 106), natural history museum collections (n = 45) and other sources (n = 12), informed by recent advances in the taxonomy of the genus Mola. Furthermore, separation in species distributions were seen when comparing sampling latitude and sea surface temperature. The findings imply that the longline fisheries observer sunfish data from Australia and New Zealand is a mix of species, and not dominated by M. mola as previously assumed. Mean catch per unit Effort (2001-13) in 1° latitude/longitude grids off Pacific Australia and New Zealand were predominantly < 1 sunfish.1,000 hooks-1 (up to 6.5 in some areas) with no statistical significant upwards or downwards trends detected over time in four fishing ground subareas, each presumably dominated by either Masturus lanceolatus, Mola alexandrini or Mola tecta. Widespread specimen identification errors had previously obscured a more complex Molidae zoogeography in the area, highlighting that phylogenetic analyses of sunfish bycatch globally would benefit species-level conservation status evaluations. 1 Introduction The ocean sunfishes (genera Mola and Masturus, Family Molidae) are a somewhat overlooked group of large teleosts, infamous for their odd shape resembling 'swimming heads' without tails, and for including the world's heaviest bony fish (Sawai et al. 2018). They are difficult to study, but with the advances in modern technology they have experienced a surge in research in recent years, revealing they are not the peculiar, sluggish oddities of nature they have traditionally been considered (e.g. Cartamil and Lowe, 2004; Watanabe and Sato, 2008). Instead, their diet and evidently high numbers worldwide suggest they play an important ecological role as predators of gelatinous zooplankton (Breen et al. 2017; Grémillet et al., 2017; Phillips et al. 2017). Advances in telemetry, digital imagery and other technologies continue to confirm that ocean sunfish are active predators, hunting at depth in dynamic frontal systems (Nakamura et al. 2015; Thys et al. 2015; Sousa et al. 2016a, b). However much of their life history is still unknown, as is the global zoogeography of all taxa in the family. including the generic use of M. mola, are also common in longline fisheries in other parts of the world (e.g.

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Section: Potential Bias In Interpreting Distribution Patternsmentioning

confidence: 55%

Giant jelly eaters on the line: Species distribution and bycatch of three dominant sunfishes in the Southwest Pacific

Nyegaard

Loneragan

Hall

et al. 2018

Estuarine, Coastal and Shelf Science

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“…First, we were successful in characterising the habitats available within our study region thanks to the use of a PCA based on in-situ environmental conditions monitored simultaneously to the megafauna survey (Lambert et al, 2018). The quality of models was reasonable to fairly good regarding the standard of habitat modelling for these organisms (good deviances and good predictions-sightings adequacy; see for comparison: Vilchis et al, 2006;Becker et al, 2014;Breen et al, 2017;Lambert et al, 2017a). The habitat modelling highlighted a range of habitat strategies based on the specificity and inter-annual stability of species preferences.…”

Section: Discussionmentioning

confidence: 99%

The persistence in time of distributional patterns in marine megafauna impacts zonal conservation strategies

Lambert

eacutemus

Ridoux

2019

Preprint

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The main type of zonal conservation approaches corresponds to Marine Protected Areas (MPAs), which are spatially defined and generally static entities aiming at the protection of some target populations by the implementation of a management plan. For highly mobile species the relevance of an MPA over time might be hampered by temporal variations in distributions or home ranges. In the present work, we used habitat model-based predicted distributions of cetaceans and seabirds within the Bay of Biscay from 2004 to 2017 to characterise the aggregation and persistence of mobile species distributional patterns and the relevance of existing MPA network. We explored the relationship between population abundance and spatial extent of distribution to assess the aggregation level of species distribution. Specific core areas of distributions were determined, based on predicted distributions, as the smallest spatial extent including 50% of the population present in the Bay of Biscay and their persistence was calculated over the 14 studied years. The relevance of MPA network was assessed regarding aggregation and persistence. The potential to zonal conservation was confirmed for spatially aggregated and persistent species, as bottlenose dolphins or auks. We showed that aggregation level alone is not sufficient to determine candidates to zonal conservation, since some species might be aggregated in space, but poorly persistent in time (black-legged kittiwake). Nonetheless, some loosely distributed species with strong persistence might not benefit from existing zonal conservation due to poor overlap between existing MPA networks and their core areas of distribution (great skuas). We thus have demonstrated that both aggregation and persistence have potential impact on the amount of spatiotemporal distributional variability encompassed within static MPAs. Our results exemplified the need to have access to a minimal temporal depth in the species distribution data when aiming to designate new site boundaries for the conservation of mobile species.

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“…Aerial surveys have become widely used in cetacean abundance estimation, especially over large or remote areas, and they have recently been applied to other marine taxa ranging from sharks [ 20 – 22 ] and rays [ 23 ] to bony fish [ 57 , 58 ] and turtles [ 59 ]. Furthermore, dedicated aerial surveys for marine mammals provide platforms of opportunity for recording and estimating the abundance of vulnerable or data-poor marine species.…”

Section: Discussionmentioning

confidence: 99%

Using tagging data and aerial surveys to incorporate availability bias in the abundance estimation of blue sharks (Prionace glauca)

et al. 2018

Self Cite

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There is worldwide concern about the status of elasmobranchs, primarily as a result of overfishing and bycatch with subsequent ecosystem effects following the removal of top predators. Whilst abundant and wide-ranging, blue sharks (Prionace glauca) are the most heavily exploited shark species having suffered marked declines over the past decades, and there is a call for robust abundance estimates. In this study, we utilized depth data collected from two blue sharks using pop-up satellite archival tags, and modelled the proportion of time the sharks were swimming in the top 1-meter layer and could therefore be detected by observers conducting aerial surveys. The availability models indicated that the tagged sharks preferred surface waters whilst swimming over the continental shelf and during daytime, with a model-predicted average proportion of time spent at the surface of 0.633 (SD = 0.094) for on-shelf, and 0.136 (SD = 0.075) for off-shelf. These predicted values were then used to account for availability bias in abundance estimates for the species over a large area in the Northeast Atlantic, derived through distance sampling using aerial survey data collected in 2015 and 2016 and modelled with density surface models. Further, we compared abundance estimates corrected with model-predicted availability to uncorrected estimates and to estimates that incorporated the average time the sharks were available for detection. The mean abundance (number of individuals) corrected with modelled availability was 15,320 (CV = 0.28) in 2015 and 11,001 (CV = 0.27) in 2016. Depending on the year, these estimates were ~7 times higher compared to estimates without the bias correction, and ~3 times higher compared to the abundances corrected with average availability. When the survey area contains habitat heterogeneity that may affect surfacing patterns of animals, modelling animals’ availability provides a robust alternative to correcting for availability bias and highlights the need for caution when applying “average” correction factors.

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New insights into ocean sunfish (Mola mola) abundance and seasonal distribution in the northeast Atlantic

Cited by 18 publications

References 33 publications

Giant jelly eaters on the line: Species distribution and bycatch of three dominant sunfishes in the Southwest Pacific

Giant jelly eaters on the line: Species distribution and bycatch of three dominant sunfishes in the Southwest Pacific

The persistence in time of distributional patterns in marine megafauna impacts zonal conservation strategies

Using tagging data and aerial surveys to incorporate availability bias in the abundance estimation of blue sharks (Prionace glauca)

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