Largest global shark biomass found in the northern Galápagos Islands of Darwin and Wolf

León, Pelayo Salinas de; Acuña-Marrero, David; Rastoin, Etienne; Friedlander, Alan M.; Donovan, Mary K.; Sala, Enric

doi:10.7717/peerj.1911

Cited by 57 publications

(30 citation statements)

References 81 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The positive effect of full protection identified for Carangidae (jacks) is also consistent with global findings that jacks are not dependent on isolation and age for recovery but receive considerable protection from fishing mortality within large, well-enforced, no-take MPAs . The high biomass of sharks we found inside fishing closures was consistent with global findings that these fishes receive considerable protection from fishing mortality within large, well-enforced, and old no-take MPAs Salinas de León et al 2016) and was somewhat contrary to concerns that the mobility of large pelagic species impedes recovery in fully protected MPAs (Gruss et al 2011). Both families are highly targeted for commercial export and domestic markets, and our findings imply that fishing-gear and size restrictions and quotas to limit fishing effort could be key strategies to building sustainable fishing practices.…”

Section: Discussionsupporting

confidence: 87%

Fishing‐gear restrictions and biomass gains for coral reef fishes in marine protected areas

Campbell¹,

Edgar

Stuart‐Smith

et al. 2018

Conservation Biology

View full text Add to dashboard Cite

Considerable empirical evidence supports recovery of reef fish populations with fishery closures. In countries where full exclusion of people from fishing may be perceived as inequitable, fishing-gear restrictions on nonselective and destructive gears may offer socially relevant management alternatives to build recovery of fish biomass. Even so, few researchers have statistically compared the responses of tropical reef fisheries to alternative management strategies. We tested for the effects of fishery closures and fishing gear restrictions on tropical reef fish biomass at the community and family level. We conducted 1,396 underwater surveys at 617 unique sites across a spatial hierarchy within 22 global marine ecoregions that represented 5 realms. We compared total biomass across local fish assemblages and among 20 families of reef fishes inside marine protected areas (MPAs) with different fishing restrictions: no-take, hook-and-line fishing only, several fishing gears allowed, and sites open to all fishing gears. We included a further category representing remote sites, where fishing pressure is low. As expected, full fishery closures, (i.e., no-take zones) most benefited community- and family-level fish biomass in comparison with restrictions on fishing gears and openly fished sites. Although biomass responses to fishery closures were highly variable across families, some fishery targets (e.g., Carcharhinidae and Lutjanidae) responded positively to multiple restrictions on fishing gears (i.e., where gears other than hook and line were not permitted). Remoteness also positively affected the response of community-level fish biomass and many fish families. Our findings provide strong support for the role of fishing restrictions in building recovery of fish biomass and indicate important interactions among fishing-gear types that affect biomass of a diverse set of reef fish families.

show abstract

Section: Discussionsupporting

confidence: 87%

Fishing‐gear restrictions and biomass gains for coral reef fishes in marine protected areas

Campbell¹,

Edgar

Stuart‐Smith

et al. 2018

Conservation Biology

View full text Add to dashboard Cite

show abstract

“…ecosystems also present high abundances of sharks and other top predators (e.g., jacks, wahoos, tunas, and groupers) and thus support a higher biomass than near-shore insular and coastal environments (Friedlander et al, 2012;Salinas de León et al, 2016). Due to the prevailing oceanic conditions and presence of large pelagic species, these sites are ideal for activities such as diving and sport fishing.…”

mentioning

confidence: 99%

Reef fish structure assemblages in oceanic islands of the eastern tropical Pacific: Revillagigedo Archipelago and Clipperton atoll

et al. 2019

View full text Add to dashboard Cite

Revillagigedo Archipelago and Clipperton atoll are oceanic islands located in the eastern tropical Pacific. The composition and trophic structure of their fish assemblages have never been characterized in detail, and the aim of this study was therefore to analyse the community structure and assess the similarity of fish assemblages between these two areas. Underwater visual fish censuses were conducted using band transects at two depth levels in three islands of the Revillagigedo Archipelago (Socorro, San Benedicto, and Roca Partida) and at Clipperton atoll. We calculated ecological indices (density, richness, Shannon diversity, Pielou evenness, and taxonomic distinctiveness) for each transect. These were compared in order to determine quantitative differences among the islands and bathymetric levels. Qualitative analyses (ANOSIM, nMDS, and SIMPER) were also performed. Finally, we analysed the trophic structure of the assemblages and the functional diversity of the four studied sites. The results showed significant differences for all indices, except diversity (H′). Roca Partida was the site with greatest abundance and richness due to the presence of pelagic species in large numbers. No significant differences were found in functional diversity, suggesting a high degree of ecological redundancy. Lower‐level carnivores with mean trophic level values of between 3.3 and 3.8 dominated both areas. The ordination analysis did not show a clear difference in fish composition among the islands, although Clipperton atoll has a particular fauna characterized by endemic species (Thalassoma robertsoni and Stegastes baldwini). In conclusion, the fish communities of the studied areas seem quite similar, but their assemblage structure differs. In particular, Clipperton is differentiated by the influence of endemic species.

show abstract

“…The evidence used to support so called 'inverted biomass' or trophic pyramids, in which greatest biomass occurs at the top of the food chain, comes primarily from diver-based (belt-transect) underwater visual surveys at remote atolls and islands (Newman et al 2006, DeMartini et al 2008, Sandin et al 2008b, Salinas de León et al 2016, Bradley et al 2017b. Toplevel predator systems can be sustained through subsidiary inputs, i.e.…”

Section: Discussionmentioning

confidence: 99%

Is seeing believing? Diver and video-based censuses reveal inconsistencies in roving predator estimates between regions

Asher¹,

Williams²,

Harvey³

2019

Mar. Ecol. Prog. Ser.

View full text Add to dashboard Cite

Coral reef research programs in Hawaii primarily use diver-based underwater visual censuses in ≤30 m depths to assess roving predator populations between the Main (MHI) and North western Hawaiian Islands (NWHI). As a probable consequence of survey biases, results from some methods imply remarkably top-heavy trophic pyramids that potentially inflate the scale of differences between remote and populated regions. Other limitations include the absence of predator information in > 30 m depths. To better understand regional differences, we compared shallow-water roving predator abundances and estimated predator length-frequencies between 2 diver-based visual assessment methods (stationary point count ['SPC'] and towed-diver) and 2 video sampling techniques (unbaited and baited remote underwater stereo-video systems: RUVS and BRUVS). We also surveyed 30−100 m ('mesophotic') roving predators using RUVS and BRUVS. As with diver-based assessments, RUVS and BRUVS sampled considerably more roving predators in the NWHI versus the MHI, with patterns remaining consistent between methods. However, the NWHI:MHI scales of difference for RUVS and BRUVS tended to be substantially lower than for diver surveys. The largest discrepancies were recorded for the giant trevally Caranx ignobilis, where NWHI:MHI abundance ratios varied by > 2 orders of magnitude between diver SPC and all other methods. Although our results corroborate substantially higher roving predator densities in the NWHI, this study demonstrates that the application of different methods can result in strikingly dissimilar predator estimates. Continued assessments among survey techniques, coupled with the inclusion of mesophotic surveys, remain vital to improving understanding of pre dator populations, providing information that is properly aligned with management and conservation needs.

show abstract

Largest global shark biomass found in the northern Galápagos Islands of Darwin and Wolf

Cited by 57 publications

References 81 publications

Fishing‐gear restrictions and biomass gains for coral reef fishes in marine protected areas

Fishing‐gear restrictions and biomass gains for coral reef fishes in marine protected areas

Reef fish structure assemblages in oceanic islands of the eastern tropical Pacific: Revillagigedo Archipelago and Clipperton atoll

Is seeing believing? Diver and video-based censuses reveal inconsistencies in roving predator estimates between regions

Contact Info

Product

Resources

About