Modeling population dynamics of scyphozoan jellyfish (Aurelia spp.) in the Gulf of Mexico

2018 ◽  
Vol 591 ◽  
pp. 167-183 ◽  
Author(s):  
N Henschke ◽  
CA Stock ◽  
JL Sarmiento
Keyword(s):  
Population Dynamics ◽  
Gulf Of Mexico ◽  
Scyphozoan Jellyfish

scholarly journals Population Structures and Levels of Connectivity for Scyphozoan and Cubozoan Jellyfish

Diversity ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 174
Author(s):  
Michael J. Kingsford ◽  
Jodie A. Schlaefer ◽  
Scott J. Morrissey
Keyword(s):  
Population Dynamics ◽  
Population Structure ◽  
Spatial Scales ◽  
Causal Factors ◽  
Local Populations ◽  
Population Structures ◽  
Elemental Chemistry ◽  
Low Levels ◽  
Scyphozoan Jellyfish ◽  
Few Data

Understanding the hierarchy of populations from the scale of metapopulations to mesopopulations and member local populations is fundamental to understanding the population dynamics of any species. Jellyfish by definition are planktonic and it would be assumed that connectivity would be high among local populations, and that populations would minimally vary in both ecological and genetic clade-level differences over broad spatial scales (i.e., hundreds to thousands of km). Although data exists on the connectivity of scyphozoan jellyfish, there are few data on cubozoans. Cubozoans are capable swimmers and have more complex and sophisticated visual abilities than scyphozoans. We predict, therefore, that cubozoans have the potential to have finer spatial scale differences in population structure than their relatives, the scyphozoans. Here we review the data available on the population structures of scyphozoans and what is known about cubozoans. The evidence from realized connectivity and estimates of potential connectivity for scyphozoans indicates the following. Some jellyfish taxa have a large metapopulation and very large stocks (>1000 s of km), while others have clade-level differences on the scale of tens of km. Data on distributions, genetics of medusa and polyps, statolith shape, elemental chemistry of statoliths and biophysical modelling of connectivity suggest that some of the ~50 species of cubozoans have populations of surprisingly small spatial scales and low levels of connectivity. Despite their classification as plankton, therefore, some scyphozoans and cubozoans have stocks of small spatial scales. Causal factors that influence the population structure in many taxa include the distribution of polyps, behavior of medusa, local geomorphology and hydrodynamics. Finally, the resolution of patterns of connectivity and population structures will be greatest when multiple methods are used.

scholarly journals Population Dynamics Reveal a Core Community of the Common Bottlenose Dolphin (Tursiops truncatus) in Open Waters of the South-Western Gulf of Mexico

2021 ◽  
Vol 8 ◽  
Author(s):  
Jaime Bolaños-Jiménez ◽  
Eduardo Morteo ◽  
Christian A. Delfín-Alfonso ◽  
Pedro F. Fruet ◽  
Eduardo R. Secchi ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Gulf Of Mexico ◽  
Bottlenose Dolphins ◽  
Closed Population ◽  
Quantitative Evidence ◽  
Photo Identification ◽  
The Core ◽  
Mobile Species ◽  
Common Bottlenose Dolphin ◽  
Main Driver

The presence of transient and temporary individuals in capture-mark-recapture studies may violate the assumption on equal catchability, and thus yield biased estimates. We investigated the effects of residency patterns on population parameters of bottlenose dolphins inhabiting the coastal waters off the Alvarado Lagoon System (ALS), Veracruz, Mexico. We hypothesized that this population is open but there exists a “core community” that behaves as a closed population. Between 2006 and 2010, we conducted 75 photo-identification surveys and recorded 263 dolphin group encounters, in which 231 dolphins were identified. Individuals present during only one season, classified as transients (n = 85), were excluded from the study, and a standardized residency index (IH4) was computed for each dolphin that remained in the sample (n = 146). We used the K-means clustering method to split the sample into groups based on individual (seasonal, annual) IH4 values. These clusters were named as regular residents (RR, n = 55), occasional residents (OR, n = 45), and occasional visitors (OV, n = 46). The cumulative frequency of newly identified individuals displayed an asymptotic trend for the whole sample and all clusters, indicating that most of the individuals present in the study area during the study period were identified. The assumption of demographic closure was tested to define the core community, and was rejected for the whole sample and the OV cluster (p < 0.001 in both cases), indicating that the population is open. The closure assumption was not rejected for RR and OR clusters (χ2 = 6.88, DF = 13, p = 0.91, and χ2 = 17.8, DF = 16, p = 0.33, respectively), indicating that these clusters were demographically closed over the 5-year period. Thus, we defined this aggregation of individuals as the “core community”. The closed population model Mth indicated that the total abundance of this core community was 123 individuals (95% CI: 114–133). Our results provide quantitative evidence of the existence of a core community in open waters of the Gulf of Mexico, and points toward residency pattern as a main driver of population dynamics. These results highlight the importance of considering residency patterns when dealing with heterogeneity in the sample of a highly mobile species.

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