Predicting the distribution of the scyphomedusa Chrysaora quinquecirrha in Chesapeake Bay

Abstract

Jellyfish blooms are important events controlling plankton dynamics in coastal waters worldwide, yet factors that influence bloom development are not well understood. We used the scyphomedusa Chrysaora quinquecirrha as a model to examine physical factors that control jellyfish populations and to develop an ecological forecasting system. Over 700 in situ observations collected from Chesapeake Bay and its tributaries during 1987-2000 were used to develop habitat models that predict the probability of occurrence and the likely concentration of medusae as a function of seasurface temperature and salinity. Medusae were found within a relatively narrow range of temperature (26 to 30°C) and salinity (10 to 16). Regression analyses reveal that a combination of temperature and salinity is a significant predictor of medusa occurrence. Assessments of the predictive performance of these models using medusae and environmental data collected at independent survey sites (n = 354) indicated that model-predicted medusa occurrence and concentration correspond well with observations. Our models can be forced with near-real time and retrospective estimates of temperature and salinity to generate probability of occurrence maps of C. quinquecirrha medusa presence and abundance in order to better understand how this top predator varies in space and time, and how this species could potentially affect energy flow through the Chesapeake Bay system.

Development, biological regulation, and fate of ctenophore blooms in the York River estuary, Chesapeake Bay

“…The decline in M. leidyi blooms in the York River estuary appears to be due primarily to predation by C. quinquecirrha scyphomedusae, and not to bottom-up food limitation of M. leidyi. Chrysaora medusae appeared in surface waters early to mid-summer (June-July) at water temperatures > 25°C and salinities ranging from 16 to 20 psu (Decker et al 2007) (Fig. 6).…”

Simulating the effect of hypoxia on bay anchovy egg and larval mortality using coupled watershed, water quality, and individual-based predation models

“…Jung & Houde (2004) found that larval mortality rates in the mainstem of the Chesapeake Bay were lower in years with high salinity (dry years), potentially because of the effects of salinity on predator abundance and spatial distribution (Purcell & Decker 2005). Year types (wet/dry) affect the spatial distribution of sea nettles (Decker et al 2007), as well as the timing of peak sea nettle abundance (Breitburg & Fulford 2006). The potential effect of year types on ctenophores is less clear, as they do not appear to be affected by temperature and salinity, but may be affected by food availability and sea nettle predation (Purcell & Decker 2005).…”

Role of winds and tides in timing of beach strandings, occurrence, and significance of swarms of the jellyfish Crambione mastigophora Mass 1903 (Scyphozoa: Rhizostomeae: Catostylidae) in north-western Australia

“…The reason we chose to do the likelihood test on wind direction and tide as categorical variables, in addition to the more dynamical multivariate approach described below, was to attempt to have a easy to use decision tool for lifeguards patrolling what is a popular tourist beach. Logistic regression analysis has previously been used (Decker et al, 2007) to relate jellyfish presence/ absence data to environmental variables. We used a similar approach using the LOGIT module in SYSTAT (Systat Software Inc., San Jose, USA) to determine which predictor variable contributed the best fit to the regression, and which combination of environmental variables best described the relationship between the occurrence of jellyfish strandings and the potential environmental predictor variables of tide range, model current direction and speed, wind speed and wind direction at Broome.…”