Challenges in monitoring mobile populations: Applying bayesian multi‐site mark–recapture abundance estimation to the monitoring of a highly mobile coastal population of bottlenose dolphins

Nykänen, Milaja; Oudejans, Machiel G.; Rogan, Emer; Durban, John W.; Ingram, Simon

doi:10.1002/aqc.3355

Cited by 5 publications

(2 citation statements)

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“…For instance, assessments of survey effort of terrestrial, avian and marine vertebrates using established monitoring approaches (e.g., line transect surveys, constant-effort-search surveys, capture-recapture) have demonstrated significant geographical and seasonal heterogeneity (e.g., wetland birds, Calladine et al, 2009;Wiest and Shriver, 2016; fin and sperm whales, Mannocci et al, 2018;bottlenose dolphins, Symons et al, 2018). Specifically, boat-based transects to quantify the size of cetacean populations range from six times a month at some locations (Smith et al, 2016) to two times a month during summer months only (Nykänen et al, 2020), with the latter potentially impeding records of recruitment and/or detection of growth/decline and associated factors (Wilson et al, 1999;Symons et al, 2018). For marine turtles, UASs provide an unprecedented opportunity to estimate the actual size of breeding populations empirically, including both males and females, which is not possible when using beach-monitoring counts alone that are based only on the female component of the population (i.e., track, nest or female counts), and typically require modelling approaches to infer population size (Jolly-Seber models [POPAN] or multi-state open robust design [MSORD]) (Chaloupka and Limpus, 2004;Pfaller et al, 2013;Schofield et al, 2017;Whiting et al, 2020).…”

Section: Discussionmentioning

confidence: 99%

Aerial Drones Reveal the Dynamic Structuring of Sea Turtle Breeding Aggregations and Minimum Survey Effort Required to Capture Climatic and Sex-Specific Effects

Dickson

Tugwell

Katselidis³

et al. 2022

Front. Mar. Sci.

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Quantifying how animals use key habitats and resources for their survival allows managers to optimise conservation planning; however, obtaining representative sample sizes of wildlife distributions in both time and space is challenging, particularly in the marine environment. Here, we used unoccupied aircraft systems (UASs) to evaluate temporal and spatial variation in the distribution of loggerhead sea turtles (Caretta caretta) at two high-density breeding aggregations in the Mediterranean, and the effect of varying sample size and survey frequency. In May–June of 2017 to 2019, we conducted 69 surveys, assimilating 10,075 inwater turtle records at the two sites. Optimal time interval between surveys to capture the dynamics of aggregations over the breeding period was <2-week intervals and >500 turtles (from the combined surveys). This minimum threshold was attributed to the core-area use of female turtles shifting across surveys in relation to wind direction to access warmer nearshore waters and male presence. Males were more widely distributed within aggregations than females, particularly in May when mating encounters were high. Most males were recorded swimming and oriented parallel to shore, likely to enhance encounter rates with females. In contrast, most females were generally stationary (resting on the seabed or basking), likely to conserve energy for reproduction, with orientation appearing to shift in relation to male numbers at the breeding area. Thus, by identifying the main factors regulating the movement and distribution of animals, appropriate survey intervals can be selected for appropriate home range analyses. Our study demonstrates the versatility of UASs to capture the fine-scale dynamics of wildlife aggregations and associated factors, which is important for implementing effective conservation.

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Section: Discussionmentioning

confidence: 99%

Aerial Drones Reveal the Dynamic Structuring of Sea Turtle Breeding Aggregations and Minimum Survey Effort Required to Capture Climatic and Sex-Specific Effects

Dickson

Tugwell

Katselidis³

et al. 2022

Front. Mar. Sci.

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“…A multi-site approach would also allow the application of alternative mark-recapture models, e.g. using a Bayesian framework (Durban et al, 2005;Nykänen et al, 2020) or other spatially explicit approaches (Borchers & Efford, 2008). Ideally, line transect surveys specifically designed to ensure equal coverage probability in combination with distance sampling would be employed to conduct regular monitoring of cetacean abundance and distribution, as were conducted under the SCANS projects in the European Atlantic shelf waters, for example (Hammond et al, 2013).…”

Section: Implications For Conservation Biology and Future Workmentioning

confidence: 99%

Population Biology of Fin Whales: Applying Demographic and Evolutionary Approaches to Studying Populations

Schleimer¹

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Acknowledgements 6'population' is used for all these concepts, so it is not amazing that confusion has arisen. This confusion is the more dangerous, since 'population' (in the meaning of local breeding population) plays an important part in the theory of (micro-) evolution.Jonckers (1973) 2005). Tulloch et al. (2019) aimed to quantify the effect of climate change on the recovery of baleen whale populations. Their ecosystem-modelling approach accounted for predatorprey interactions, projected changed in sea surface temperature, changing prey availability, changing distribution of whales, shifts in migration patterns, and inter-specific competition. Baleen whale populations in the Southern Hemisphere were predicted to decline in response to reduced prey availability from increased sea surface temperature and increasing interspecific competition (Tulloch et al., 2019). The study serves as an example of the complex dynamics between predator and prey populations and their physical environment. Statistical models may not succeed in the exact representation of natural systems, but they can offer useful approximations of the real world or in the words of George Box ( 1979) "all models are wrong but some are useful". Conservation biologyConservation biology integrates conservation policy with theories developed in population ecology and evolutionary biology to mitigate anthropogenic impacts on biological diversity and to prevent the extinction of species (Soulé, 1985). Populations are the primary target of management and policy directives that aim to provide effective protection to small or declining populations (Shaffer, 1981). In this context, the terms 'management unit' or 'stock' are frequently used to refer to "geographical areas with restricted interchange of the individuals of interest with adjacent areas" (Taylor & Dizon, 1999). How this definition translates to delineating management units in natural populations is a matter of debate (Palsbøll et al., 2007;Taylor & Dizon, 1999). While population genetics provide a means of quantifying population differentiation, the decision on the threshold level of interchange, in this case gene flow, mainly depends on the demographic context and management objectives (Palsbøll et al., 2007;Taylor & Dizon, 1999). A statistical test on whether the null hypothesis of panmixia can be rejected at an arbitrary level is rarely sufficient to delineate meaningful management units (Palsbøll et al., 2007;Taylor & Dizon, 1999). Weakly structured populations or those following a stepping-stone model pose a particular challenge as to where to draw the line (Spies et al., 2015).Once a management unit has been defined, population viability analysis (PVA) can be employed to estimate the likelihood of reaching a threshold level, e.g. extinction, under current or managed conditions (Boyce, 1992). PVAs are generally quantitative model-based assessments of extinction/persistence that can incorporate elements of spatially-explicit and/or individual-based models, sensitivity analysis, or genetic ef...

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The longest recorded movement of an inshore common bottlenose dolphin (Tursiops truncatus)

Genov

Železnik²,

Bruno

et al. 2022

Mamm Biol

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Information on movements and connectivity among populations of animals is important for the delineation of units to conserve, so that demographic parameters, such as abundance, fecundity and mortality, can be placed in an appropriate population and conservation context. Common bottlenose dolphins (Tursiops truncatus) are often considered relatively ‘resident’ and demonstrating strong site fidelity to specific areas. However, this perception may partly be an artefact of the distribution and ‘habitat use’ of cetacean researchers, rather than animals themselves, and bottlenose dolphins have been shown to be capable of substantial movements, often in relatively short periods of time. Here, we report on two long-distance movements of a common bottlenose dolphin within the Mediterranean Sea, across the Tyrrhenian, Ionian and Adriatic Seas, and subsequently back across all three seas to Ligurian Sea, making these the two longest recorded movement for this species in the Mediterranean Sea to date and some of the longest in the world. We also review published records of long-distance movements in this species worldwide. This study highlights the utility of photo-identification and the importance of regional data sharing. We argue that photo-identification comparisons are always worthwhile and the results are informative regardless of the presence or absence of matches, especially with the ongoing advances in automated matching software.

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Challenges in monitoring mobile populations: Applying bayesian multi‐site mark–recapture abundance estimation to the monitoring of a highly mobile coastal population of bottlenose dolphins

Abstract: Challenges in monitoring mobile populations -Applying Bayesian multi-site mark-recapture abundance estimation to the monitoring of a highly mobile coastal population of bottlenose dolphins Ingram, S

Cited by 5 publications

References 84 publications

Aerial Drones Reveal the Dynamic Structuring of Sea Turtle Breeding Aggregations and Minimum Survey Effort Required to Capture Climatic and Sex-Specific Effects

Aerial Drones Reveal the Dynamic Structuring of Sea Turtle Breeding Aggregations and Minimum Survey Effort Required to Capture Climatic and Sex-Specific Effects

Population Biology of Fin Whales: Applying Demographic and Evolutionary Approaches to Studying Populations

The longest recorded movement of an inshore common bottlenose dolphin (Tursiops truncatus)

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