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Marine biota are redistributing at a rapid pace in response to climate change and shifting seascapes. While changes in fish populations and community structure threaten the sustainability of fisheries, our capacity to adapt by tracking and projecting marine species remains a challenge due to data discontinuities in biological observations, lack of data availability, and mismatch between data and real species distributions. To assess the extent of this challenge, we review the global status and accessibility of ongoing scientific bottom trawl surveys. In total, we gathered metadata for 283,925 samples from 95 surveys conducted regularly from 2001 to 2019. We identified that 59% of the metadata collected are not publicly available, highlighting that the availability of data is the most important challenge to assess species redistributions under global climate change. Given that the primary purpose of surveys is to provide independent data to inform stock assessment of commercially important populations, we further highlight that single surveys do not cover the full range of the main commercial demersal fish species. An average of 18 surveys is needed to cover at least 50% of species ranges, demonstrating the importance of combining multiple surveys to evaluate species range shifts. We assess the potential for combining surveys to track transboundary species redistributions and show that differences in sampling schemes and inconsistency in sampling can be overcome with spatio-temporal modeling to follow species density redistributions. In light of our global assessment, we establish a framework for improving the management and conservation of transboundary and migrating marine demersal species. We provide directions to improve data availability and encourage countries to share survey data, to assess species vulnerabilities, and to support management adaptation in a time of climate-driven ocean changes.

The jumbo squid Dosidicus gigas was recently claimed to be an iteroparous species with ovaries returning to an immature, resting stage after spawning. Analysis of the data and figures presented in two recent articles revealed that this claim was based on misinterpretation of histological information and that Dosidicus is not iteroparous. Having consensus on the reproductive strategy of Dosidicus is important for the management of fisheries for this species. KEY WORDS: Dosidicus gigas, jumbo squid, oogenesis, iteroparity, reproduction, Recently, two articles on the reproductive biology of the large nektonic jumbo squid Dosidicus gigas (d'Orbigny, 1835) (Ommastrephidae) have been published: Hernandez-Munoz et al. (2016) and Perez-Palafox et al. (2019). [...]

Fishery discards supplement food for many seabirds, but the impacts of declining discards are poorly understood. Discards may be beneficial for some populations but have negative impacts by increasing bycatch risk or because they are junk-food. The Falkland Islands support > 70% of global black-browed albatross Thalassarche melanophris populations, which feed on discards. However, the effect of discards on population demographics, and implications of fishery management changes, are unknown. We analysed stomach contents of black-browed albatross chicks across eight breeding seasons (2004–2020) from New Island, Falkland Islands, to assess variation in discard consumption and how this relates to foraging conditions and breeding success. Across years, 68%–98% of samples contained natural prey, whilst 23%–88% of samples contained fishery discards. Discard consumption was positively related to fishery catches of hoki Macruronus magellanicus and sea surface temperature anomalies SSTA (°C), and negatively related to breeding success. These results suggest a diet-switching behaviour for Falkland Islands albatrosses, whereby birds switch from preferred natural prey to suboptimal discards when environmental conditions, and hence natural feeding opportunities, are unfavourable. Crucially, this study highlights that fishery discards do not compensate for poor natural foraging conditions for breeding albatrosses in the long term. [ABSTRACT FROM AUTHOR]

The eastern Pacific jumbo squid (Dosidicus gigas) is one of the largest and most abundant squid of the world ocean. To reveal possible interannual variability in the life span, statoliths were used to determine the age of mature females belonging to two modal size groups (500 mm mantle length) collected before (1991-1996), during (1997-1998), and after (1999-2011) a strong El Nino event in Peruvian waters. We found that water temperatures encountered between the third and sixth months of ontogenesis had the strongest negative effect on age. Together with a weaker but significant negative effect of temperatures encountered during early life (first to third months) and later ontogenesis (seventh and eighth months), these temperature parameters (along with other environmental factors) were important in determining whether a given animal had a 1-year life cycle (early maturation and small size) or a 1.5- to 2-year life cycle (delayed maturation and large size). The possible cause of a sudden increase in abundance of large D. gigas in 2000-2001 is discussed. L'encornet geant (Dosidicus gigas) du Pacifique oriental est un des calmars les plus grands et les plus abondants des oceans de la Terre. Afin de cerner une eventuelle variabilite interannuelle de sa duree de vie, nous avons determine l'age de statolithes de femelles matures appartenant a deux groupes modaux de tailles (longueur 500 mm) prelevees avant (1991-1996), durant (1997-1998) et apres (1999-2011) un fort evenement El Nino en eaux peruviennes. Nous avons demontre que les temperatures de l'eau rencontrees entre le troisieme et le sixieme mois de l'ontogenese avaient le plus grand effet negatif sur l'age. Combines aux effets negatifs plus faibles, bien que significatifs, des temperatures rencontrees en debut de vie (du premier au troisieme mois) et plus tard au cours de l'ontogenese (septieme et huitieme mois), ces parametres de temperature (en plus d'autres facteurs ambiants) etaient importants pour determiner si un animal avait un cycle biologique de 1 an (maturite precoce et de petite taille) ou de 1, 5-2 ans (maturite retardee et taille plus grande). La cause possible d'une augmentation soudaine de l'abondance du grand groupe de D. gigas en 2000-2001 est abordee. [Traduit par la Redaction], Introduction Squid are short-lived animals having mostly annual or subannual life cycles, high growth and maturation rates, and a single spawning period (semelparity) (Boyle and Rodhouse 2005). Compared with long-lived, [...]

The Falkland Islands conduct one of the few targeted skate fisheries in the world with total annual catches of several thousand tonnes.  This bottom trawl fishery is characterized by relatively low catch volumes and product yield that challenge commercial profitability. Recently, one Falkland Islands fishing company acquired a large proportion of the skate ITQ, and to optimise its fishing operations, proposed a research collaboration with the Falkland Islands Fisheries Department for assessing the performance of trawls equipped with either standard 110 mm codend mesh, or larger 300 and 400 mm meshes. The results of the trial confirmed the efficiency of larger mesh codends to decrease finfish bycatch by 97–98%. Additionally, trawls with 400 mm mesh significantly decreased the bycatch of commercially valueless small skates that would experience high discard mortality. As a result of the trial, the Falkland Islands Government implemented a regulatory licence condition of 400 mm codend mesh for targeted skate fishing. Besides greater production efficiency, vessel operators are incentivized by possible wider access throughout the fishing zone. Further initiatives are anticipated to develop management measures by individual species, continue improving conservation through bycatch mitigation in all fisheries, and diversify Falklands skate products in global markets. [ABSTRACT FROM AUTHOR]