Population Structures and Levels of Connectivity for Scyphozoan and Cubozoan Jellyfish

Abstract

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.

Offshore aquaculture of finfish: Big expectations at sea

“…The damage they inflict is particularly pronounced in the gills of the fish. This topic has been reviewed by Callaway et al 225 and recently by Clinton et al 226 In offshore waters, jellyfish may be less abundant due to the distance to the hard substrate where polyps live, despite the large range of dispersion of some species (10s to 1000s of km) 227 . However, offshore structures can serve as propagators of jellyfish 228 and offshore farms are affected by jellyfish blooms 229 …”

Use of eDNA to Determine Source Locations of Deadly Jellyfish (Cubozoa) in an Open Coastal System

“…Considerable knowledge gaps, namely, understanding surrounding population dynamics, distribution limits, and the locality of benthic life history stages (polyps), exist surrounding the ecology of cubozoan jellyfish [11,14,17]. Importance is placed upon understanding the locality of polyps as they are the source of stinging medusa and, given their asexual characteristics [18], play a major role in the population dynamics and distributional limits of cubozoans [11,[17][18][19][20].…”

“…Considerable knowledge gaps, namely, understanding surrounding population dynamics, distribution limits, and the locality of benthic life history stages (polyps), exist surrounding the ecology of cubozoan jellyfish [11,14,17]. Importance is placed upon understanding the locality of polyps as they are the source of stinging medusa and, given their asexual characteristics [18], play a major role in the population dynamics and distributional limits of cubozoans [11,[17][18][19][20]. Additionally, growing evidence suggests that population stocks of some of the ~50 cubozoan species [21] are of small spatial scales and therefore the locality of the polyp stage is central to this understanding [17,[22][23][24][25][26].…”

“…Importance is placed upon understanding the locality of polyps as they are the source of stinging medusa and, given their asexual characteristics [18], play a major role in the population dynamics and distributional limits of cubozoans [11,[17][18][19][20]. Additionally, growing evidence suggests that population stocks of some of the ~50 cubozoan species [21] are of small spatial scales and therefore the locality of the polyp stage is central to this understanding [17,[22][23][24][25][26]. The ability to study these aspects of cubozoan ecology, however, are logistically challenging to undertake.…”

“…Further, as C. fleckeri medusae have largely been observed along the north side of Magnetic Island, primarily within Horseshoe Bay, it is possible that the area may represent a local stock of the jellyfish. This provides an opportunity to test a developing paradigm that C. fleckeri commonly have population stocks of small spatial scales [17,22,26,28].…”